Latest Advances in Stroke Treatment

Aug 26, 2023

Latest Advances in Stroke Treatment

For anyone having a stroke, time is everything. Getting help quickly can make the difference between recovery and disability. You will take away an understanding of stroke risk factors and new stroke therapies from this discussion. Speaker: Jeremy Heit, MD

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0 ->

7.064 -> My name's Jeremy Heit.

7.98 -> I'm currently one of the fellows in neuro-interventional

10.313 -> radiology, and I'll describe what that is in just a minute.

13.16 -> And I'll be staying on at Stanford as staff

15.43 -> next year, so I'll be around for hopefully quite a long time.

19.18 -> So a little bit of background about me.

21.46 -> I trained, actually, here at Stanford.

23.23 -> I did an MD and a PhD here at Stanford, ended in 2008.

26.83 -> And then I decided the weather was too nice.

28.73 -> I needed to harden myself up.

30.36 -> So I went to Boston.

31.72 -> I did an internship in internal medicine

33.96 -> at the Brigham and Women's Hospital.

35.77 -> And then I did my radiology residency

37.73 -> at Massachusetts General Hospital.

39.76 -> And then my wife was sick of shoveling all the snow

41.885 -> and decided, actually, the weather is better here,

43.75 -> so we came back here, and we've been here

45.458 -> for two more years while I've been doing my fellowship.

48.37 -> So it's good to be back in California.

50.2 -> And I want to talk to you about a topic that's

52.63 -> very important for our field.

54.53 -> And by way of introduction to neuro-interventional radiology,

58.53 -> it sounds like a mouthful.

60 -> My wife still doesn't think I have a real job,

62.31 -> because it sounds futuristic.

63.81 -> And it kind of is.

65.099 -> But basically, what it is as we are

66.76 -> the specialists of the blood vessels of the brain and spine.

70.07 -> And most of what we do is minimally

71.96 -> invasive surgery in the brain through inside

74.74 -> of blood vessels.

75.87 -> And I'll show you how that pertains to stroke as we

78.62 -> talk about stroke later today.

81.98 -> So I have no financial conflicts of interest.

84.31 -> I'm a fellow.

85.71 -> So I don't have any money, either.

87.69 -> [LAUGHTER]

88.896 -> So what we'll talk about tonight,

90.27 -> a little bit of background about what an ischemic stroke is.

94.11 -> I'll talk about what it is, what causes it, and a little bit

97.29 -> about the biology of how we think about stroke,

99.47 -> in terms of treating it.

100.592 -> And then I want to spend a little bit of time talking

102.8 -> about how we image stroke.

104.4 -> That's become a very important topic,

106.23 -> and very important in how we decide

107.94 -> who we can take for a procedure that we perform

110.87 -> as neuro-interventionalists.

112.51 -> Talk about what those procedures are currently.

114.61 -> It's a very exciting time to be a neuro-interventionalist.

117.026 -> And then talk about, and speculate a little bit about,

119.43 -> what the future might hold for endovascular stroke treatment.

123.52 -> So let's start off by talking about what is ischemic stroke?

126.45 -> Well, this is a picture many of you may have seen before.

128.924 -> It's very popular and put out by the American Heart Association.

131.59 -> And I like it because it's a very nice summary

133.506 -> of what a patient having a stroke might look like.

135.91 -> This is a gentleman who's trying to smile.

138.08 -> And what you can see is that his smiles asymmetric.

141.34 -> This side looks normal.

142.47 -> He's got a good grin.

143.57 -> His cheek is coming up.

144.87 -> But this side, he has a droop.

146.91 -> This cheek is not moving upward.

148.85 -> His eye's a little bit droopy.

150.75 -> And moreover, if this were a very dramatic stroke,

152.97 -> you would find that he has profound weakness

155.06 -> in his right arm, his right leg.

157.34 -> His sensation on the right side of his body may be affected.

160.47 -> These are very profound neurologic symptoms.

162.94 -> And just to keep you straight in going forward,

165.27 -> we think about stroke in opposites.

167.17 -> So this patient, where all the symptoms

169.01 -> are on the right side of his body,

170.55 -> has a problem on the left side of his brain.

173.97 -> Now, patients with these symptoms

175.92 -> can be very severe like that or less severe.

178.21 -> But overall in this country, stroke, every year,

180.62 -> affects 800,000 people.

182.27 -> So it's a very big problem for our medical system.

185.29 -> 140,000 of those people will die.

187.84 -> That's a very high mortality rate.

189.454 -> And it is the leading cause of disability in this country,

191.87 -> so it's a big financial impact to our health care system,

194.39 -> as well.

195.23 -> Expenditures that the US spends treating and caring

198.3 -> for patients with stroke exceed $73 billion a year.

201.75 -> So it's a big problem.

203.75 -> So those are the symptoms that you might see.

206.05 -> There are other variations of that,

207.75 -> but that's sort of a good overall picture.

209.5 -> But what causes that?

210.65 -> Well, a good way to think about stroke

213.132 -> is an analogy to something most of you

214.715 -> are probably familiar with, which is a heart attack.

216.985 -> When you have a heart attack, you

218.36 -> block an artery going to the heart.

220.23 -> Well, similarly, when you have a stroke,

222.51 -> it's a problem with giving blood flow to the brain.

224.839 -> And we think about it as something

226.255 -> that happens very rapidly, and it's usually

228.046 -> a blood clot that blocks a major blood vessel in the brain

231.9 -> or on the way up to the brain.

233.62 -> And this is a nice schematic from a recent review

235.68 -> in the literature.

236.59 -> And what you see here is there are blood vessels in our neck

239.09 -> that run up toward the brain.

240.36 -> This is the internal carotid artery.

242.47 -> And then they turn, they have a very torturous course,

244.97 -> and then this right here represents a small blood

247.13 -> clot blocking a major artery in the brain called

249.51 -> the middle cerebral artery, or MCA.

251.94 -> The MCA provides blood flow to around 80%

254.91 -> of the cerebral hemispheres, and most large strokes

258.209 -> affect this blood vessel.

260.11 -> So in the patient I just showed you,

262.04 -> he would have a blockage in the left middle cerebral artery,

264.719 -> which would account for his symptoms,

266.26 -> including the right-sided weakness,

268.3 -> right-sided facial droop.

271.35 -> So now I want to jump forward to thinking

273.89 -> about-- we see what the blood vessel looks like,

276.01 -> but what's going on in this patient's head?

278.32 -> And I've made some images to try to schematize what this is.

281.03 -> So these are images just from an MRI,

282.71 -> but I've kind of color-coded them

284.299 -> to help us think about, conceptually,

285.84 -> what's going on in the brain.

287.422 -> Normally we're all sitting here with good blood

289.38 -> flow to our brains.

290.28 -> If you interrupt that blood flow,

292.34 -> the effects are very immediate.

294.05 -> You can think of a stroke as an immediate symptom.

296.75 -> You're doing fine.

297.55 -> Suddenly, you're very weak.

298.76 -> It happens like that.

300.47 -> And there's kind of two things that can happen to the brain

302.99 -> when you don't get enough blood flow.

304.89 -> One is that the tissue can die very rapidly.

308 -> Neurons do not tolerate the lack of blood flow for very long.

312.02 -> And if that happens, you get dead tissue.

314.98 -> But not everything that's downstream of the blocked

318.18 -> artery dies right away.

319.489 -> Kind of like if you're driving on a highway

321.28 -> and there's an accident, if you have the right app,

323.48 -> you can get off and kind of go around the back streets

325.37 -> and get back on the highway and keep going.

327.31 -> The brain has a way to reroute blood

329 -> to areas that aren't getting enough blood flow.

331.03 -> But if that route takes too long,

333.22 -> it's not enough to keep the tissue alive.

335.47 -> But you have another whole area of tissue

337.53 -> that's at risk of going on to die

339.87 -> if something's not done to restore

341.41 -> blood flow to the brain.

343.07 -> And in the medical literature, we've

345.3 -> termed these two areas core and penumbra.

348.07 -> Core refers to the core infarction

350.28 -> that happens in a stroke.

351.87 -> That's dead tissue.

353.22 -> We think of it as irreversibly damaged.

355.32 -> It doesn't get better.

356.26 -> It doesn't come back.

357.92 -> By contrast, the penumbra refers to the tissue

361.25 -> that's at risk of injury, but it's not dead yet.

364.58 -> It's not functioning normally.

366.55 -> If we can restore the blood flow to the brain,

369.13 -> we think we can save the penumbra.

372.45 -> We spend a lot of time and appropriate energy

375.93 -> in imaging these two areas, because it

377.85 -> makes tremendous impact, as I'll tell you later,

380.93 -> in how we can treat patients with stroke.

383.102 -> So at Stanford, we've been a leader

384.56 -> in some of the advanced imaging that images core and penumbra,

387.85 -> and here's one example from a recent patient.

389.99 -> This is a patient who's coming in with a stroke.

392.41 -> This is an MRI sequence called the diffusion-weighted

394.85 -> sequence, and what this assesses is the movement of water.

397.67 -> And when brain tissue dies, water doesn't move,

400.13 -> and you can take a picture of that.

401.67 -> And right here in the brain, this is a stroke.

404.6 -> It's a relatively small stroke.

406.639 -> And now in this same patient, we have a way

408.43 -> to quantitatively assess the blood flow up to the brain

411.93 -> by injecting a label that you can see by MRI.

414.68 -> And you can see that although the patient has

416.97 -> a relatively small stroke of core infarction that's there,

420.74 -> there's a large amount of territory that's

423.17 -> not getting enough blood flow, and likely functioning poorly,

426.397 -> which is the patient's penumbra.

427.73 ->

430.417 -> So let's go back to an image that looks like this.

432.5 -> This is the patient that's having a stroke.

434.97 -> And we can see that let's say this part is core.

438.25 -> It's infarcted.

438.96 -> We're not going to get that amount of tissue back.

441.29 -> However, this part of the brain might leave the patients

444.45 -> with relatively less profound symptoms.

448.01 -> However, there's also this area of penumbra

450.49 -> that, if that is not saved, results in much worse symptoms.

454.97 -> If we're able to reperfuse the brain,

457.29 -> meaning restore the blood flow, then everything that's blue

461.28 -> is saved.

461.84 -> It goes back to normal.

463.37 -> And we're left with the same size of core infarction

466.19 -> that the patient came in with.

467.44 -> That's what we want to do as physicians, because that's

469.797 -> giving the patient the best chance at having

471.63 -> a good outcome.

473.45 -> By contrast, if we aren't able to open the blood vessel that's

476.71 -> blocked going to the brain, and there's no reperfusion,

479.98 -> the tissue that is the penumbra will eventually

482.78 -> go on and infarct, and you'll have a larger core infarction.

486.79 -> And as the amount of brain tissue

488.46 -> that dies increases in size, so do the consequences.

493.01 -> So in thinking about that, I think

494.92 -> you can probably understand that reperfusion is really

498.06 -> the goal of all stroke therapy.

499.96 -> We work very rapidly through both medical treatments

502.98 -> and endovascular treatments that I'll describe in a bit

505.31 -> to get the blood vessel open, in order

507 -> to minimize the amount of injury that a brain sustains.

510.586 -> Let me show you a few examples, just

512.085 -> to illustrate these points.

513.419 -> This is from a patient that I took care of,

515.21 -> a 69-year-old woman who was out with some friends

518.49 -> when she very suddenly develop weakness in her left arm

521.559 -> and a droop in her left face.

523.88 -> She came right into Stanford.

525.2 -> She was brought by her friend.

526.45 -> She had a head CT scan that really looked very normal.

529.25 -> There is no evidence of a large infarction here.

531.98 -> There's no evidence of overt injury.

534.41 -> She got perfusion imaging to assess what the penumbra is,

537.31 -> and you can see she has a very large amount of tissue that

540.985 -> is at risk of infarction.

543.4 -> We also were able to image the blood vessels non-invasively.

546.58 -> This is a CT angiogram.

548.61 -> And what you can see is the normal side of the brain,

551.04 -> this is the middle cerebral artery, in white.

553.93 -> And if you look on the other side, it starts off fine,

556.63 -> but there's a hole right there.

558.9 -> That's a blood clot.

560.53 -> So that's the blood clot that's partially blocking this artery,

564.21 -> and the patient does not have very many blood vessels going

566.95 -> to this part of the brain.

568.48 -> Without blood flow in that part of the brain,

570.41 -> she has this large penumbra.

572.29 -> So this is a patient you can help,

573.92 -> because she's not had a big stroke here yet,

576.07 -> of core infarction.

577.22 -> But if we don't get that blood vessel open, she's in trouble.

580.72 -> So she was given a medication called tPA,

583.01 -> which is tissue Plasminogen Activator.

584.96 -> It's a clot-busting medication.

586.97 -> And literally in front of your eyes,

588.7 -> she started moving the left arm.

590.97 -> She regained her strength quite dramatically.

593.56 -> She then got an MRI scan around an hour later.

596.35 -> And an MRI is better at showing where the actual core

599.51 -> infarction is, and she had a very small core infarction.

601.87 -> This is less than a milliliter in volume.

603.89 -> It's very tiny.

605.64 -> Her perfusion had normalized, except in the area immediately

608.37 -> around the stroke, which we expect to see.

610.76 -> And her blood vessel is now open.

613.44 -> The medication worked, and she made a great outcome.

617.61 -> Here's another patient I took care of,

619.62 -> a 68-year-old gentleman who came in with right-sided weakness

623.23 -> and had a very small stroke on an MRI scan.

625.44 -> You can barely even see it, it's happening so quickly.

628.64 -> This is a patient that we took for endovascular stroke

631.02 -> therapy, and we were able to find the blocked

633.34 -> artery in the brain.

634.54 -> And I'll describe this later, but this is an angiogram where

637.039 -> we've injected a black dye.

639.31 -> Looks black by x-ray.

640.89 -> And what we see is that there's nothing here

643.34 -> where there should be a lot of blood vessels.

645.44 -> This is where the middle cerebral artery should be,

647.73 -> and the arrow denotes the blockage.

650.18 -> We were able to get the blood clot out, restore

652.95 -> all this blood flow, and the patient

654.82 -> was left with basically the same size

656.91 -> stroke that he came in with.

658.78 -> Again, that's what you want to do.

660.425 -> Get the blood flow to the brain back, minimize the damage

663.28 -> so it doesn't get bigger.

664.61 -> This gentleman also made an excellent recovery.

667.85 -> Here's a different patient.

669.22 -> This is a little bit bigger core infarction on an MRI,

672.55 -> but you can see it's still not that big, relative to the size

675.64 -> of the brain.

676.789 -> This was another patient that was brought to our endovascular

679.33 -> suite for endovascular stroke therapy.

682.124 -> And this was done before I arrived here,

683.79 -> when some of the technology was older.

685.86 -> And again, you can see, not a lot of blood vessels here

688.469 -> where the middle cerebral artery should be.

690.26 -> And there's a blockage.

691.29 -> This just stops.

692.28 -> It should go like that.

693.88 -> So the doctors worked their best.

696.024 -> They worked very hard.

696.94 -> They could not get this open, despite everything

698.94 -> that they did.

699.93 -> And the consequences of that for this patient

701.92 -> was that the patient went on to have

703.67 -> a much larger stroke and a much worse clinical outcome.

707.16 -> So those are three examples of why

708.875 -> you want to have the blood vessel open, because it really

711.25 -> does maximize the chance of having

712.79 -> a good recovery from a stroke.

715.45 -> So in going forward, keep in mind

717.182 -> that what we're going to be talking about

718.89 -> are ways to reperfuse the brain.

721 -> Get the blood vessel open, restore the blood flow,

723.81 -> minimize the size of the stroke.

725.517 -> And again, I've been speaking a lot about we

727.35 -> want to do this quickly.

728.88 -> This is a widely cited paper in our literature from Dr. saver

732.265 -> at UCLA, where he calculated, well,

734.9 -> how much injury do you get in the brain

737.23 -> on a per-minute basis, on a per-stroke basis?

739.97 -> And a widely quoted number is this one.

742.48 -> Per minute, if you don't restore blood flow,

744.85 -> you lose around two million neurons.

748.08 -> That's a lot.

749.41 -> So you really want to get that blood vessel open.

751.82 -> And I was alarmed to see that one stroke accelerates

754.37 -> your aging by around 36 years.

756.77 -> So these are a little bit of extrapolation,

759.91 -> because he's doing this on just some rough math.

762 -> But the point is that you want to get blood vessel open,

765.74 -> because there are real effects to not doing so, in terms

768.47 -> of how a patient will do.

770.63 -> OK, so what can we do to help patients with a stroke?

774 -> Well, we have a few options.

776.15 -> In 1995, there was a very large study

778.98 -> published in the New England Journal of Medicine

781.01 -> showing that intravenous administration

783.28 -> of the clot-busting medication tPA

785.51 -> was very effective in taking care of patients with stroke.

788.89 -> OK, tPA, again, stands for tissue Plasminogen Activator.

792.1 -> It's injected through an IV, and it acts to find a blood clot

795 -> and actively dissolve it.

796.73 -> So patients that got this drug, compared

798.92 -> to a control group of patients that were just

800.85 -> managed medically, 30% of the patients who got the drug

803.92 -> had a favorable outcome and were functionally independent.

807.26 -> That's very good data.

808.19 -> And this was just a landslide, in terms of stroke therapy.

811.22 -> It was a real game-changer at the time.

813.22 -> Because prior to that, all you could

815.04 -> do were sort of measures to try to increase the blood pressure,

817.977 -> make sure you try to get more blood flow that way.

820.06 -> But you weren't really doing anything

821.601 -> to actively get rid of the blood clot.

824.15 -> Now, the downside of tPA is that the data

827.61 -> shows there's a very limited time window

829.45 -> in which this is helpful.

831.25 -> The original trial said you need to give the medication

833.92 -> within three hours.

835.65 -> And follow-up studies have said you

837.18 -> need to get it into the patient within four and a half hours.

840.55 -> Many patients with strokes do not get to the hospital in time

844.25 -> to get treated with tPA.

845.9 -> In fact, it's only around 7% to 10%

848.04 -> of patients now that are even eligible for tPA.

850.74 -> These are very small numbers in the context

852.64 -> of what I showed you demographically

854.55 -> goes on in the country earlier.

856.51 -> So that's a problem.

858.33 -> That being said, if you can get to the hospital,

860.33 -> it's a good thing.

861.73 -> So subsequent to that, in 1999, there

864.73 -> was another trial called the PROACT II trial, from Japan.

867.22 -> And this trial showed that there's another option.

870.73 -> If you're able to get a catheter, which is just

873.2 -> a hollow plastic tube, from inside the arteries

876.076 -> all the way up into the arteries in the brain

877.95 -> where the blood clot is, and then directly deliver

880.15 -> a similar clot-busting medication,

882.63 -> you can make an improvement in how the patients will do.

885.33 -> And importantly, they extended the time window to six hours.

889.22 -> So this actually increases the number of patients

891.35 -> that you can offer a treatment to pretty significantly.

894.77 -> That being said, these early studies

896.46 -> were also plagued with high rates of complications.

899.82 -> A lot of these patients developed

901.25 -> bleeding in the brain, and that was a significant concern,

904.13 -> in terms of how you care for people.

906.05 -> And it is something that's still limited the use of this therapy

909.38 -> broadly.

911.355 -> Now, more recently, there's been a technique called

913.48 -> mechanical thrombectomy, and this

916.04 -> is a technique that's also an endovascular therapy

918.425 -> from inside blood vessels.

919.81 -> And the goal of this is to mechanically remove the clot.

923.55 -> And you can do that by either putting a device up

926.04 -> to grab the clot and pull it out,

928.34 -> putting a device up to grab the clot

930.02 -> and suck it out like a vacuum.

932.01 -> But these newer devices have actually

934.51 -> begun to be a game-changer, which I'll

936.42 -> talk about more in a minute.

937.84 -> And more importantly, the recent trials

940.29 -> have extended the window in which these devices can be used

942.96 -> from six hours to eight hours.

945.08 -> And many people, including even us,

946.75 -> are taking this beyond eight hours

948.54 -> now and getting very good results.

951.59 -> So we're moving in the right direction,

953.97 -> in terms of being able to fight this clock

956.08 -> and being able to help people.

957.78 -> But we've got to know who will really benefit from what we do,

961.29 -> and that's where imaging has played a big role.

963.73 -> And one of the things we're likely see going forward

966.02 -> is that imaging could be a way to stop the clock.

968.71 -> Wouldn't it be nice if a patient woke up

970.87 -> with a stroke-- we have no idea what time it started.

973.975 -> Maybe it happened five minutes before they woke up.

976.1 -> Maybe it happened two hours after they went to bed,

979.22 -> and it's done.

980.37 -> But what if you had a way to sort that out and say,

982.917 -> you know what?

983.5 -> They're eligible for treatment.

984.791 -> Well, people are working on ways to use advanced imaging,

987.3 -> particularly at places like Stanford,

989.13 -> to say, this is a patient who still can be helped,

991.8 -> even though we don't know when the stroke started.

993.89 -> And I expect that this will be an exciting area

995.848 -> to watch in the years to come.

998.03 -> OK, so how do we use imaging to kind of fight this clock

1001.74 -> and decide who is a good patient to take to the cath lab that

1005.13 -> will benefit from our therapy?

1006.644 -> Well, again, remember, what we're trying to do

1008.56 -> is reperfuse the brain and minimize the amount of injury.

1012.17 -> And in thinking about who is a good patient

1014.49 -> to put through a procedure to try to reperfuse the brain,

1017.54 -> there are three criteria.

1019.39 -> You want to have a patient with a relatively small core,

1022.92 -> a small amount of infarction.

1025.26 -> This patient should also have a large amount

1028.069 -> of tissue at risk of infarction if we are not

1030.48 -> successful in getting the blood vessel open.

1033.069 -> It's that mismatch that's really critical.

1035.73 -> And lastly, there's got to be a blood clot that we can get to.

1038.374 -> There's a big difference in a blood clot

1040.04 -> that's at the base of the skull, where the arteries are just

1042.67 -> coming into the brain, in terms of being able to access it,

1045.39 -> to something that's the way up near the top of the brain.

1047.839 -> The technical difficulties of getting

1050.07 -> further out, and practicality, is very different.

1054.501 -> So we've got to have a way to answer these three

1056.5 -> questions for every patient that we're

1058.11 -> going to consider taking to the cath lab for a procedure.

1061.18 -> And at Stanford, we are very good at doing this

1063.53 -> with two different ways of advanced imaging.

1065.58 -> We can use MRI and we can use CT,

1067.54 -> and there are reasons for each that I'm happy to talk about

1070.28 -> with you guys later.

1071.35 -> But both of these can basically get at the same points.

1073.89 -> An MRI is very good at finding how big is

1076.19 -> the area of infarction?

1078.12 -> It's very good at finding how big is the penumbra?

1080.54 -> Again, by injecting a dye that changes how the MRI senses it,

1084.51 -> and you can quantitatively assess blood flow

1086.37 -> to each side of the brain.

1087.7 -> And it's very good at finding whether there's

1089.62 -> a vessel that's missing.

1091.29 -> Similarly, CT is very good at finding

1095.15 -> early signs of a stroke.

1096.38 -> Not as good as MRI, but good enough.

1098.76 -> It's equally good at perfusion, in terms of assessing

1101.59 -> the size of the penumbra.

1103.21 -> And it's excellent at finding a cut-off

1105.57 -> in a vessel that represents the location of the blood clot.

1109.1 -> So any patient that's going to be considered for stroke

1111.49 -> therapy, by and large, should have these three questions

1114.43 -> answered by CT or MRI scan.

1116.2 -> And that's really becoming the standard of care nationally.

1119.82 -> OK, so now we know how to pick the patients

1122.21 -> that we think we can help.

1123.84 -> We know that we can get them up and do something about it.

1126.84 -> So what exactly can we do?

1128.83 -> Well, endovascular stroke therapy is very, very exciting

1131.99 -> right now.

1132.92 -> And that's because in the last five months--

1135.68 -> almost five months.

1136.61 -> It's almost May-- there have now been five randomized control

1139.66 -> trials, all published in the New England Journal of Medicine,

1142.49 -> showing a remarkable benefit to endovascular stroke therapy,

1146.04 -> compared to medical management alone.

1148.8 -> So I want to put one data slide up.

1151.31 -> So I apologize if it's too much, but I

1153.03 -> think this is a really nice way to illustrate this.

1155.58 -> This slide's inspired by Dr. Albers, one of our stroke

1157.975 -> neurologists, who gave an excellent talk about this

1160.1 -> recently.

1161.04 -> And what you're looking at here, on the y-axis,

1163.65 -> this is the percentage of patients with a good outcome

1166.96 -> after a stroke.

1168.26 -> The medical literature, we usually define

1169.98 -> a good outcome as someone who is functionally independent

1173.14 -> and with minimal symptoms.

1174.94 -> Because that's a patient that overall

1177.06 -> still has a very good quality of life,

1179 -> and maybe even a normal quality of life,

1181.37 -> and is also someone who is not stuck needing assistance,

1186.61 -> and so on and so forth.

1187.64 -> So obviously, that's what you want to be.

1189.08 -> Someone who still has a very good quality of life.

1191.27 -> And then on the x-axis here, these

1193.91 -> are the names of the five trials.

1195.51 -> You can see they give them kind of goofy names.

1197.51 -> And in each trial, there's both a medical arm

1200.53 -> and there's an endovascular arm.

1202.63 -> All the patients that got endovascular therapy

1205.38 -> got equal medical therapy.

1206.77 -> So this is added benefit to what we normally do for patients.

1210.25 -> And you can see, if you look at the patients who

1212.45 -> underwent endovascular stroke therapy, it's really remarkable

1216.67 -> how much better they can do, if you

1218.55 -> select the patients properly by the criteria

1221.54 -> I discussed earlier.

1223.08 -> 33% good outcome to 19%-- this was

1225.33 -> the first study that came out.

1227.64 -> 53% of patients treated have a good outcome compared to 30%.

1232.25 -> 44%, 60%, 71%.

1234.17 -> These are excellent, excellent numbers.

1236.34 -> And this makes a big, big difference

1237.98 -> for each one of these patients.

1239.66 -> And even on a bigger scale, it's a massive difference

1242.51 -> to our society, both in how people are doing,

1245.03 -> how their health is, the financial impact of stroke.

1248.55 -> These are steps in the right direction.

1250.99 -> So again, what is happening to patients

1252.97 -> that are in this red group that were brought for a procedure?

1256.01 -> Well, as I discussed earlier, there's three options.

1258.74 -> We can give tPA, that clot-busting medication,

1262.41 -> directly into the clot to break it apart.

1265.51 -> We can put a big catheter up to the clot

1267.59 -> and try to suck it out.

1269.105 -> Or we can use a device that looks like this.

1271.92 -> This has been termed a stentriever.

1273.93 -> These were initially developed as stents for narrowing

1276.524 -> in the blood vessels, and they weren't very good for that.

1278.94 -> But what we found by accident in testing

1280.68 -> them is that they're very good at grabbing blood clots

1282.93 -> and pulling them back out.

1284.092 -> So as long as you can leave the stent attached to something

1286.55 -> you can pull, you can use it to get a blood clot out

1288.956 -> of a vessel.

1290.42 -> So all these things I'm talking about now

1292.81 -> require things to be inside an artery that's way up here

1296.17 -> in your brain.

1297.31 -> But how do you get it up there?

1298.785 -> Well, everything we do has to have

1301.16 -> a little bit of road-mapping and driving on the highway.

1305.01 -> Basically, we put our equipment into an artery in the leg.

1307.91 -> Again, these are largely catheters,

1309.92 -> which are just long, hollow plastic tubes.

1312.13 -> And then we use x-rays to navigate them

1314.03 -> from an artery in the leg, all the way backwards

1316.029 -> into the neck, up into the arteries in the brain.

1319.19 -> So it's a pretty big distance.

1320.44 -> I'm a short guy, but you can imagine a taller person--

1322.73 -> that's a long way to go.

1324.21 -> And it's really a testament to material science

1326.78 -> that we're able to do this.

1328.55 -> When I first got interested in this field,

1330.84 -> these procedures were not only extremely difficult,

1333.08 -> and in many cases not possible, they took hours to do.

1337.11 -> These procedures now can be done in 20 minutes.

1340.2 -> They can be very, very fast.

1341.48 -> So there's been a remarkable advancement

1343.29 -> in catheter technology biomaterials,

1345.84 -> such that you can have a wire in your hand,

1348.45 -> and by turning it a little bit, you

1349.97 -> can manipulate a device that's all the way up in the brain.

1352.53 -> That's really an amazing feat.

1354.23 -> And it's really made a big difference for patients.

1356.74 -> So what does this look like?

1358 -> Well, here's a patient that we took care of,

1360.15 -> and I thought it would be interesting to show you

1361.39 -> guys how we get a device up there,

1362.83 -> and sort of the curly-course-Q that's required.

1366.01 -> So this is a short movie.

1367.59 -> This is a catheter here that's all the way up

1369.64 -> in the internal carotid artery in the skull.

1372 -> And then there's a smaller catheter

1373.67 -> call a microcatheter that's been put through this,

1376.25 -> that winds its way up into the artery in the brain right here.

1378.87 -> Here's the tip of the microcatheter.

1380.83 -> The blood clot that we're going after is right here.

1383.76 -> So if you watch, you can see, this is the device.

1387.3 -> This is the stentriever getting pushed up.

1390.78 -> And it goes through the microcatheter.

1392.44 -> Look at the turns this thing has to make to get all the way out,

1395.38 -> up into the brain.

1396.84 -> Again, that's really remarkable.

1398.24 -> It's navigating 180-degree turns, 360-degree turns,

1402.47 -> by pushing something down in the leg.

1404.89 -> And once we get the device all the way up

1406.6 -> there, we can basically unsheathe it, expose the stent,

1409.48 -> and then we're able to grip the clot.

1412.89 -> After we do that, you can pull the clot out.

1415.8 -> This is the same patient.

1416.937 -> I'm going to warn you, this is a patient who was awake--

1419.27 -> which we do on purpose.

1420.228 -> I'm happy to talk about that later-- and very confused.

1422.984 -> So you're going to see the head moving around a lot.

1425.15 -> He was very comfortable.

1426.18 -> We don't let our patients hurt.

1427.52 -> But it's going to look funny.

1428.92 -> This is what happens when we start

1430.54 -> to pull the blood clot out.

1432.57 -> So first thing we do is we're moving this big sucking

1435.54 -> catheter up along this stentriever right here.

1439.194 -> And you can see the patient's kind

1440.61 -> of chit-chatting away, moving around, very confused.

1443.057 -> And now you're going to see that we're

1444.64 -> going to start to pull the stentriever

1446.223 -> device into the catheter.

1450.967 -> Here it comes.

1451.55 -> We're moving along, moving along, and almost there.

1455.51 -> Pop-- we got it out.

1457.64 -> Blood clot's gone.

1458.99 -> Patient's doing OK.

1460.78 -> So that's sort of what this looks like.

1462.42 -> And you can kind of appreciate the difficulty of doing it,

1465.14 -> but also the fact we can do it.

1467.54 -> And it's really, I think, quite remarkable.

1469.56 -> All right, so I want to show you a few success stories.

1471.977 -> These are all patients that I've taken

1473.56 -> care of during my fellowship.

1475.29 -> This first one is a 63-year-old surfer girl.

1478.1 -> You heard both the age and the description correctly.

1480.892 -> She was actually running at the gym on the treadmill, which

1483.35 -> she still does every day-- extremely active, very fit--

1486.27 -> when she collapsed.

1487.84 -> She was brought to an outside hospital.

1489.91 -> They thought she was having a stroke.

1491.87 -> They gave her tPA to try to break up the blood clot,

1494.82 -> and they asked us if there was anything else we can do.

1497.58 -> She was put on a helicopter, flown to Stanford,

1499.577 -> and as soon as she landed on the roof,

1501.16 -> she came right down to an MRI scanner,

1503 -> where our whole team was waiting, and she had the scan.

1506.28 -> Her diffusion-weighted imaging shows

1507.99 -> she has a very, very small core infarction.

1510.615 -> It's tiny.

1511.659 -> Could barely even see it.

1512.7 -> You might even miss it.

1514.06 -> There's an arrow to help.

1515.79 -> But look at her perfusion.

1517.51 -> Her penumbra is unbelievably large.

1520.31 -> This is her dominant hemisphere.

1521.73 -> It's actually on the left side.

1523.31 -> These are as if you're looking at the feet of the patient.

1525.86 -> But this is a remarkable penumbra.

1528.85 -> This is a great patient that you can take to the cath lab

1531.39 -> and really help.

1532.79 -> And we know where the blood clot is.

1534.72 -> Here's the normal side.

1535.79 -> Look at all these blood vessels.

1537.123 -> This is the middle cerebral artery,

1538.76 -> and look at the lack of them on this side.

1541.17 -> And this is actually the blood clot itself.

1543.59 -> You can see the blood clot using a different MRI sequence.

1547.11 -> So we've got a patient with a small existing stroke,

1550.18 -> a lot of tissue at risk, and a blood clot that we can get to.

1553.93 -> We go straight to the cath lab.

1556.64 -> So here we are, first picture we've taken.

1558.391 -> The catheter is now in the artery in the neck.

1560.306 -> We've injected the contrast dye, which is black.

1562.4 -> It winds its way up, and boom, stops.

1565.58 -> This is where the blood clot is.

1566.914 -> There should be blood vessels all the way up here,

1568.996 -> and there are not.

1569.8 -> So we know that we've got to get to there.

1572.17 -> We go further up into the arteries in the brain.

1574.58 -> We've got an aspiration catheter here.

1577.25 -> We've got a stentriever across the area of the blood clot.

1581.13 -> We suck, we pull, and we're able to open up the blood vessel.

1586.93 -> This is a great result.

1589.004 -> Here's the blood clot.

1589.92 ->

1592.96 -> This patient did great.

1594.91 -> She was in the hospital for two days, went home.

1597.3 -> She's still running every day.

1599.047 -> This is a different patient we took care of.

1600.88 -> This is a triathlete.

1601.95 -> Not all strokes happen in patients

1603.77 -> who are in their 60s or older.

1605.23 -> He's 50.

1605.87 -> He was training for a triathlon, running, when he collapsed.

1609.4 -> Again, was brought to an outside hospital.

1611.2 -> Was again given tPA.

1612.32 -> He got to the hospital quickly.

1614.34 -> Same thing-- we were called.

1615.514 -> Put him on a helicopter, flew him to Stanford,

1617.43 -> and he went straight to the MRI scan.

1619.52 -> This patient's also had a relatively small stroke.

1621.987 -> Bigger than the last one I showed you,

1623.57 -> but this is still quite small.

1625.4 -> Has a large amount of brain tissue

1626.99 -> at risk of infarcting further if we don't

1629.16 -> get the blood vessel open.

1630.66 -> And again, like the last patient, the normal side.

1633.195 -> You can see the middle cerebral artery,

1634.82 -> and look-- there's a complete absence

1637.029 -> of the middle cerebral artery on this side.

1638.82 ->

1642.01 -> He comes straight up to the cath lab.

1644.32 -> This is an image that was taken 40 minutes after arriving

1647.87 -> at Stanford, 20 minutes of which were the MRI scan.

1651.33 -> So pretty quick.

1652.451 -> And what you can see is a little bit

1653.95 -> of a different picture than what I showed you last time,

1655.66 -> and let me kind of show you what's going on.

1657.88 -> This is looking at the side of the head.

1659.664 -> This other picture here is looking

1661.08 -> at the front of the head.

1662.49 -> All of the contrast dye we've injected is coming up

1665.22 -> and instead of going out to this part of the brain,

1667.4 -> it's actually shooting backwards and going

1669.149 -> to these blood vessels in the back of the brain.

1671.81 -> And that's because there's a blood clot right here,

1674.52 -> where all of the blood vessels that are right

1676.47 -> here are not filling.

1677.7 -> This is a very bad stroke to have.

1679.72 -> This is a blood clot you want to get out.

1681.98 -> Here's another image, kind outlining

1683.57 -> the length of this blood clot.

1685.97 -> This was almost 2 centimeters long.

1689.36 -> So we were able to go across it with our equipment,

1693.67 -> grab it, pull it out, and look at the difference.

1697.21 -> Restored the blood flow.

1698.4 -> This was one pull.

1699.63 -> This whole procedure took 32 minutes.

1702.684 -> Here's the blood clot.

1703.6 ->

1706.39 -> So look what happened after that.

1707.99 -> This is how he started.

1709.98 -> His stroke got a little bit bigger, but not too much.

1712.24 -> There are a little bit of small areas

1713.781 -> of bleeding in here, which is something that can happen.

1716.46 -> Here's what the perfusion looked like, completely normal

1719.79 -> after we opened up the blood vessel.

1722.04 -> And here's what his blood vessels

1723.91 -> looked like on the MRI scan.

1725.27 -> Again, there was nothing here, and now it's normal.

1728.752 -> And I had to put this one in.

1729.96 -> This is just a great picture.

1731.168 -> This is a reconstructed image of the blood vessels from his MRI

1734.78 -> when he came in.

1735.98 -> And again, here's the blood clot right here.

1738.53 -> And there it is now.

1741.51 -> He also did very well.

1743.96 -> One more example.

1745.28 -> This is a 64-year-old gentleman who came in.

1748.27 -> Kind of subtle symptoms-- nausea, some kind

1750.96 -> of funny vision changes.

1752.7 -> And I show this case to kind of hearken

1755.31 -> back to earlier, in that why don't all patients get

1757.94 -> to the hospital quickly?

1759.59 -> Sometimes you don't know you're having a stroke.

1761.99 -> I mean, these are symptoms you've all probably

1763.906 -> had-- blurry vision.

1764.94 -> My wife called me today.

1765.97 -> She said her eyes were a little blurry.

1767.595 -> She has bad allergies.

1769.39 -> Sometimes you don't feel well.

1770.67 -> But you could be missing something that's a big problem.

1773.45 -> And that amount of confusion is to be completely expected,

1776.44 -> and it's going to limit some people getting to the hospital.

1779.12 -> This patient did get to the hospital,

1781.34 -> because the nausea was quite bad.

1783 -> And there's a very, very small stroke

1785.081 -> in the back part of the brain.

1786.33 -> This is the pons.

1787.19 -> This is a very important part of your brain.

1789.264 -> This is the part of the brain that

1790.68 -> controls your level of arousal, consciousness, basic functions

1794.49 -> of breathing and being alive.

1797.132 -> And this patient, different to what I've showed you before,

1799.59 -> has a blockage in an artery in the back of the brain.

1802.37 -> This is the basilar artery, arguably

1804.406 -> the most important artery in your body.

1806.03 -> And there's a blood clot right at the top of it

1808.48 -> that's blocking part of the posterior cerebral artery,

1811.08 -> which goes toward the back of the brain.

1812.9 ->

1815.41 -> This patient was brought right up to the cath lab,

1817.692 -> and here's the picture.

1818.65 -> You kind of see this little fuzzy interface here?

1821.28 -> That's the contrast flowing around the clot

1823.72 -> into the normal side here.

1825.52 -> But there should be something that

1827.02 -> looks like this on this side, and there's not.

1829.53 -> So the blood clot is blocking the top

1831.25 -> of this artery and the artery that goes to-- in this case,

1834.037 -> it's the right side.

1834.87 -> It's opposite.

1836.96 -> So we were able to get the blood clot out, open the patient up.

1840.9 -> Here's the blood clot.

1842.14 -> And again, the patient did very, very well.

1843.99 ->

1846.702 -> OK.

1847.61 -> So those are some examples of what we can do now.

1849.994 -> And again, this is a very exciting time.

1851.66 -> Just to give you some numbers, I mentioned

1854.7 -> that the drug tPA, when it was approved, in 30% of patients

1858.82 -> was able to open up these type of clots, and 30% of patients

1862.17 -> had a good, functionally independent outcome.

1865.28 -> We looked at the numbers that I've

1867 -> been shown for the recent trials for endovascular stroke

1869.52 -> therapy, showing an excellent outcome anywhere

1871.99 -> from 40% to 70% of patients.

1874.33 -> And in terms of how often we're able to get those blood

1877.64 -> clots out and the blood vessel open,

1879.56 -> we're successful between 80% and 85% of the time,

1882.29 -> and sometimes even higher than that.

1884.36 -> So we're very good at getting blood clots out now.

1887.24 -> So that's important to keep in mind, because what does

1889.54 -> that mean for going forward?

1890.73 -> Well, I think we're going to see a few things.

1892.69 -> There's going to be better neuro-imaging triage

1894.648 -> of patients.

1895.634 -> And a large part of this, I think,

1897.05 -> is going to be trying to stop the clock.

1898.896 -> Again, it'd be great if we could just have a standard way

1901.27 -> to scan people, know whether they're

1903.27 -> going to benefit from what we can do,

1904.95 -> and also what they're likely to benefit from.

1907.764 -> I expect there'll be some further improvements

1909.68 -> in the devices that we can use to do

1911.66 -> the mechanical thrombectomy procedures.

1913.88 -> There's been a very rapid advancement already,

1916 -> and I think they can still do better, and they will.

1918.362 -> And I think there's now going to be

1919.82 -> a lot more emphasis on timeliness of these procedures.

1923.3 -> We want to be able to get patients into a hospital,

1925.912 -> get the imaging to make sure that they're the right patient

1928.37 -> to help, and get them up to the procedure room

1930.42 -> as expeditiously as possible, in order to try to help them.

1933.99 -> Those are sort of, I think, obvious next steps.

1936.08 -> And then I think, just it would be

1937.52 -> fun to speculate for a minute, about what

1939.23 -> can a place like Stanford do?

1940.98 -> And this is what I hope that we'll

1942.45 -> be starting to see in the coming, probably, 10 years.

1945.5 -> But we can get catheters to places very quickly

1948.62 -> that really is unprecedented.

1951.12 -> And it's a really unique opportunity

1953.28 -> to start to explore, well, can we

1955.26 -> do something to change the biology of a stroke itself

1957.9 -> and the after-effects?

1959.25 -> What about stem cell therapies?

1960.98 -> What if you could deliver a stem cell?

1962.59 -> Maybe not a neuronal stem cell, maybe a cell

1965.48 -> that supports the environment that the neurons need

1967.7 -> to be nourished, and sort of change the inflammatory

1970.45 -> surroundings that those cells are bathed in,

1973.04 -> in the setting of a stroke.

1974.37 -> That could potentially be a very exciting treatment

1976.52 -> that might really alter the course of even a patient that's

1978.978 -> already had a larger stroke.

1980.65 -> What about the delivery of biologic therapies?

1983.69 -> What we do right now is we give medications.

1985.93 -> It's very effective.

1987.19 -> We've been doing it for years.

1988.81 -> But we also are now in the era where

1991.33 -> we've sequenced the genome-- I was in graduate school

1993.93 -> when that happened-- and we have a better

1996.01 -> understanding of the cellular signaling that goes on

1998.289 -> in the setting of stroke.

1999.33 -> Well, what if we can start to deliver biologic therapies?

2001.87 -> You can deliver RNA that can change gene expression.

2005.19 -> What if you can do that to calm down inflammation,

2007.29 -> promote the survival of neurons?

2009.31 -> Can you deliver these things through nanoparticles?

2011.52 -> Can you package different drugs in nanoparticles

2014.16 -> to promote neuronal survival?

2016.62 -> These are all very interesting questions,

2018.34 -> and I think we're likely to see many of these technologies

2021.4 -> start to explored and exploited.

2023.862 -> And I hope that Stanford will be on the leading edge of it.

2026.32 -> And with the resources we have, I think that we will.

2029.43 -> So just by way of summary, stroke,

2032.02 -> it's a big health problem.

2033.11 -> It's caused by blockage of an artery going in the brain

2036.06 -> or going up to the brain.

2037.76 -> We went over some of the demographic numbers.

2040.14 -> 800,000 strokes in this country alone a year.

2042.74 -> It's a big public health problem,

2044.86 -> and it's a big problem for many patients and many families.

2048.06 -> And we also talked a little bit about some

2049.81 -> of the recent emerging technologies in endovascular

2052.62 -> stroke therapy and the differences

2054.639 -> that they're making for patients.

2056.639 -> And with these changes that are already happening,

2059.392 -> I know at Stanford, we're certainly

2060.85 -> going to start taking one blood clot out at a time.

2063.531 -> Each patient, we're going to do it,

2064.989 -> we're going to do our best to help them.

2066.656 -> And there are many other hospitals that are doing this.

2068.947 -> And if we keep doing this, this can really

2070.719 -> chip away at those big numbers, and that's

2072.53 -> what we're all about.

2075.03 -> If you have friends, if you're near people that you

2077.525 -> see something like this-- this is put out by the American

2079.9 -> Heart Association.

2080.65 -> The acronyms is FAST.

2082.85 -> Do they have a facial droop?

2084.6 -> Do they have arm weakness?

2085.94 -> Do they have speech difficulty?

2087.909 -> Those can be symptoms of a stroke that may be overlooked.

2091 -> And if you see them, time to call 911.

2094 -> So think about that.

2095.46 -> You may be a person who spots that.

2097.127 -> It could happen at a restaurant.

2098.46 -> Someone may look to be drunk, and it's a stroke.

2101.052 -> So keep these things in mind, because you

2102.76 -> may be able to help someone, just by having heard about it.

2106.53 -> OK.

2107.4 -> Thank you.

2107.9 -> I'm happy to take any questions.

2111.654 -> [APPLAUSE]

2114.084 ->

2115.55 -> Sir?

2116.17 -> We talk about all these clots.

2119.04 -> Why do we get the clots in the first place?

2121.49 -> A very good question.

2124.04 -> So my job is to get the clot out.

2125.74 -> The question is, where do the clots come from?

2128.7 -> So that's a big part of taking care of patients with strokes.

2132.73 -> When you come to a place like Stanford,

2134.77 -> you can't just have a couple of people involved

2138.255 -> in the care of the patient.

2139.38 -> You need a whole host of expert people.

2142.31 -> You need neurologists.

2143.42 -> You need neuro-interventionalists.

2144.836 -> You need speech therapists.

2146.14 -> You need intensivists.

2147.75 -> You need medical doctors.

2148.875 -> You need speech therapists.

2150.66 -> And much of what happens after we get the blood clot out

2153.134 -> is getting at your question.

2154.3 -> Why is it there?

2155.57 -> The most common cause is an arrhythmia in the heart.

2158.3 -> Atrial fibrillation is the number one cause of strokes

2161.17 -> that we take care of.

2162.52 -> When the heart normally beats like this,

2164.91 -> atrial fibrillation is an arrhythmia

2166.57 -> where it's irregular.

2167.7 -> It just beats in an erratic and unpredictable manner.

2171.07 -> When that happens, there are pockets

2172.74 -> of the heart where blood is not moving through

2174.94 -> because it's getting squished out in a repeated pattern.

2178.41 -> As blood pools, it forms a clot.

2180.724 -> So there can be little blood clots that hide in the heart,

2183.14 -> and those can break off and fly up and block

2185.225 -> an artery in the brain.

2187.35 -> That's the most common cause.

2189.16 -> Another cause is disease in the arteries in the neck.

2192.412 -> It can be atherosclerotic disease and narrowing

2194.37 -> that are very inflammatory.

2195.732 -> You can get a blood clot that forms

2197.19 -> on it that can fly up and block an artery in the brain.

2199.69 -> A similar process can happen in the brain itself.

2202.42 -> Good question.

2204.448 -> The person with the basilar artery problem,

2209.904 -> because it was in the back of their neck, when

2212.632 -> they were nauseated, did they also have vertigo?

2215.835 -> This patient did not.

2216.71 -> Many of the patients do.

2217.919 -> That's a very common presentation.

2219.335 -> And again, you can imagine how that's a problem.

2222.24 -> A lot of patients have vertigo.

2223.61 -> A lot of patients feel nauseous.

2225.41 -> Good question.

2226.061 -> She was asking about whether there's

2227.56 -> vertigo from a basilar stroke.

2230.69 -> The question is why do these patients have arrhythmias?

2233.33 -> The examples I showed you were, in general,

2235.86 -> younger healthy people.

2237.28 -> Many of the patients we take care of are not.

2240.7 -> Smoking, high blood pressure, diabetes, hyperlipidemia,

2246.4 -> having your cholesterol be out of whack--

2248.28 -> these are the major risk factors for stroke.

2251.18 -> The vast majority of patients have that situation,

2253.53 -> which leads to heart disease and arrhythmias.

2255.99 -> You can also have an arrhythmia just because it's

2258.41 -> the way you were born, or because you've

2260.19 -> had some small damage at some point in your heart

2262.5 -> that's created an arrhythmia focus.

2265.182 -> And those can be things that are just bad luck.

2267.14 ->

2269.767 -> Good question.

2270.35 -> So the question is, well, what is the blood clot made out of?

2273.68 -> There's kind of two different things.

2275.96 -> One is that it can be made up largely fibrin,

2278.74 -> which is sort of a blood breakdown type of product.

2281.534 -> And that's the type of clot that you typically

2283.45 -> get from the heart.

2284.7 -> Some clots are made out of platelets,

2287.42 -> and those are more of the inflammatory type of clots that

2290.22 -> come from an atherosclerotic plaque that's very irritating,

2293.38 -> a lot of inflammatory change, and a platelet

2295.72 -> plug forms there and flies off.

2297.97 -> You can even get other, more goofy types of clots.

2300.87 -> You can get fat.

2301.85 -> Patients with trauma can have injury to bones,

2304.36 -> and fat can fly through and block an artery in the vein.

2307.54 -> So the question is, if you live far away

2310.21 -> from a place like Stanford, how do you

2312.23 -> get to a place like Stanford that can help you?

2315.27 -> How do you get a helicopter to come here?

2317.1 -> So we have a few ways.

2319.47 -> Number one is we actually have a network.

2321.52 -> So we have relationship with hospitals that people know.

2324.55 -> If the stroke comes into the emergency department,

2326.9 -> they can call us.

2327.94 -> Our doctors will be on the phone within five minutes.

2330.58 -> We'll listen to the story, understand what's going on.

2332.86 -> If it sounds like it's someone we can help,

2334.889 -> we can dispatch the helicopter and get them here.

2336.93 -> [INAUDIBLE]

2338.752 -> That's a good question.

2339.71 -> I've taken care of two patients from Eureka

2342.96 -> that were put on a small medical transport plane,

2346.11 -> landed at Moffett or at San Jose,

2347.96 -> and then were helicoptered up.

2349.87 -> It's a longer transport time.

2351.624 -> We were able to help both of them,

2353.04 -> and they both actually did very, very well.

2355.4 -> The unpredictability comes in that each patient's physiology

2358.25 -> is different.

2359.48 -> That transport time, the patients

2361.51 -> we took care of, that penumbra didn't shrink,

2365.22 -> and the core infarct didn't grow.

2367.32 -> You need to be able to make sure that the brain that's

2369.57 -> at risk of dying doesn't die as you're getting a patient here.

2372.294 -> And that's another big part of why we image patients

2374.46 -> when they get here.

2375.882 -> And then one more quick comment about stroke centers.

2378.09 -> Not all stroke centers are stroke centers.

2380.174 -> So there's comprehensive stroke centers,

2381.84 -> and there are stroke centers.

2383.51 -> So Stanford is a comprehensive stroke center.

2385.43 -> It's actually the first comprehensive stroke center.

2387.82 -> And that denotes-- losing my voice.

2391.95 -> That denotes a very high level of care.

2394.231 -> It means there's a neuro-interventionalist

2395.98 -> on call 24/7.

2397.29 -> There are neuro critical care doctors 24/7,

2399.59 -> neurosurgeons 24/7.

2401.54 -> It takes a lot of resources to be a comprehensive stroke

2404.78 -> center, and there are actually relatively

2406.61 -> few of those in the area.

2407.87 -> So the question is most of what I've

2409.41 -> talked about is the actual treatment of the clot when

2411.84 -> patients show up with a stroke.

2413.84 -> But what about preventing a stroke?

2416.31 -> And similar to what we were talking

2418.42 -> about for the other gentleman here, being healthy

2421.48 -> is the most important thing.

2423.96 -> Don't smoke.

2424.947 -> Get your blood pressure under control.

2426.53 -> If you have diabetes, make sure your glucose is well managed.

2429.57 -> Make sure your lipids are low.

2431.15 -> If you have atrial fibrillation, make sure

2433.8 -> that you are put on a medication,

2435.29 -> if it's appropriate when you talk to your doctor,

2437.5 -> to prevent a blood clot from forming in your heart.

2440.12 -> Coumadin-- there are now newer-generation medications

2442.38 -> that do the same thing.

2444.284 -> Those are important discussions to have,

2445.95 -> because a large amount of those efforts

2448.46 -> can prevent something like a stroke.

2450.456 -> We take care of a lot of patients

2451.83 -> that have atrial fibrillation, and they actually

2454.32 -> knew they had it, but for one reason or another,

2456.97 -> either they thought, oh, I don't need to take the medication,

2460.14 -> or they're in financial hardship and they

2462.172 -> can't afford the medication, and they come in with strokes,

2464.63 -> just because they weren't able to be

2466.54 -> on the medication they need.

2468.171 -> How does aspirin work at helping a stroke?

2469.92 -> So we like aspirin.

2471.76 -> It's a very good drug.

2472.685 -> So aspirin inhibits platelets, which

2474.989 -> is very good for blood vessel health.

2476.53 -> It's an anti-inflammatory.

2478.29 -> So a lot of stroke patients will benefit from aspirin.

2482.26 -> That's another drug that's been tried and true over the years.

2485.52 -> It's a very good preventative medicine.

2487.59 -> In the actual acute stroke, once it's happened,

2490.39 -> there's not a large role for it, in terms

2492.31 -> of breaking up the blood clot that caused the stroke.

2494.84 -> It's really a preventative medication,

2496.65 -> and it's a very good one.

2498.43 -> The question is whether you should be on a baby dose

2501.04 -> aspirin or a full dose aspirin.

2502.96 -> Different physicians have different opinions.

2504.92 -> I think many people now would tell you

2507.35 -> that the amount of inhibition of your platelets,

2509.642 -> whether you take a baby aspirin or a full dose,

2511.6 -> is very similar.

2512.76 -> And I would say that.

2513.77 -> So the question is, I showed two examples

2515.69 -> of patients that were exercising when they had their strokes.

2518.4 -> And it's not to discourage you all from exercising.

2520.64 -> What's good for your blood vessels

2522.056 -> is good for preventing a stroke.

2523.67 -> So there is a theoretical question about when you're

2527.73 -> exercising, you get a catecholamine surge,

2530.46 -> which is some of the hormones that help rev your body up

2532.86 -> for exercise.

2534 -> Those can affect your heart rate.

2535.84 -> So there's a theoretical possibility

2538.325 -> that as you're exercising, you may trip yourself

2540.87 -> into an irregular heart rate.

2542.41 -> Or by pumping the heart more, it may theoretically

2545.247 -> cause a blood clot to be more likely to break off.

2547.33 -> That being said, there's no good evidence for that.

2550.2 -> It's all hand-waving explanations.

2552.49 -> Most of the patients that we take care of

2554.51 -> are not these examples.

2556.56 -> But I find it neat to see people who

2558.76 -> are very active have bad luck, and that

2561.31 -> do very well afterwards.

2563.17 -> So the question is patients that get tPA.

2565.28 -> It's effective in one type of stroke--

2566.896 -> and I'll clarify that in a minute-- 30% of the time.

2569.94 -> And what are the risks of using it?

2572.02 -> So most of the strokes that I've been talking about today

2574.45 -> are what we call large vessel occlusion strokes,

2576.77 -> meaning you're blocking the internal carotid artery,

2579.33 -> the middle cerebral artery, very close to the skull base.

2582.47 -> Those are notoriously tough clots for tPA.

2585.25 -> And the 30% reflects what are the chances of tPA breaking up

2588.47 -> a clot in those locations?

2590.76 -> Now, if you have a smaller stroke

2592.55 -> because the blockage is further out,

2594.539 -> meaning you probably have a small blood clot that

2596.58 -> blocks something out here, tPA actually

2598.58 -> is more likely to help you in that situation.

2601.05 -> But it's really these big vessel clots

2603.07 -> that it just is not that effective.

2605.35 -> So people have started to look at this.

2607.26 -> There are a few ideas out there.

2609 -> If an artery this close to the skull is blocked,

2611.2 -> it's a big clot, which means there's a lot more surface area

2614.19 -> to dissolve.

2614.946 -> Which means if you give a drug through an IV,

2616.82 -> it's got to coat all that surface area to break it up,

2619.07 -> which is the taller order.

2620.66 -> That's one explanation.

2621.836 -> There have been studies to look at the length of the blood clot

2624.46 -> and how well it responds to tPA.

2626.312 -> There are very good studies showing

2627.77 -> that if a blood clot is longer than 8 millimeters,

2630.18 -> it actually responds very poorly to tPA.

2632.79 -> So people are looking at that as a criteria for selection

2636.09 -> for stroke therapy.

2637.044 -> One of the studies I showed you actually

2638.71 -> had that as a criteria.

2640.259 -> And then your second part of your questions

2642.05 -> was what is the risk of tPA?

2644.75 -> So the risk of tPA is actually the same risk

2646.86 -> that we tell patients.

2648.202 -> And the major risk I would tell you

2649.66 -> is causing bleeding in the brain.

2651.77 -> One of the examples I showed you,

2653.28 -> the patient, after we pulled the blood clot out,

2655.28 -> had a little bit of bleeding in the brain.

2657.43 -> That can certainly happen for a couple of reasons.

2659.88 -> One is that you have that whole area of brain that's not been

2663.33 -> getting a lot of blood flow.

2665.01 -> The blood vessels in that brain volume are damaged.

2667.69 -> They're leaky.

2668.66 -> So if suddenly, you open up the blood vessel

2670.73 -> and get a lot of blood pressure coming back into it,

2673.182 -> a little bit of blood can leak out.

2674.64 -> And that's what happened to the gentleman I showed you.

2676.98 -> However, you can also be unlucky and have a massive hemorrhage.

2681.24 -> So that's the concern.

2682.3 -> It's a small number of patients, but there

2684.66 -> is a real risk, both with tPA and what we do,

2687.986 -> of causing bleeding in the brain that can, frankly,

2690.11 -> be catastrophic.

2691.525 -> Do you see that happen sometimes?

2693.39 -> Very rarely.

2694.01 -> We've been lucky at Stanford, actually.

2695.634 -> Our numbers are very low for that,

2697.09 -> and we think it's because of the imaging selection that we do.

2700.13 -> But you definitely will see it.

2701.96 -> Yeah, so the question is if you are a patient who's had a TIA,

2705.52 -> does that in any way preclude you

2706.91 -> for being a candidate for endovascular stroke therapy.

2709.204 -> Is that correct?

2709.87 -> What's a TIA?

2711.07 -> A TIA is a Transient Ischemic Attack.

2714.5 -> And this is something that's a precursor, or something that's

2717.52 -> a high-risk sign, for a stroke that could happen.

2720.35 -> And usually what that means is-- I can't connect to [? box-- ?]

2724.43 -> is that it's telling you that you have a situation where

2727.575 -> there's something wrong, and your body's giving you

2729.7 -> a warning sign.

2731.35 -> TIA can be something like your arm is weak,

2734.25 -> and it concerns you.

2735.13 -> You notice it.

2735.63 -> But it gets better after a few seconds, or even

2737.588 -> a couple of minutes.

2738.79 -> You may have a hard time speaking for a few minutes,

2741.03 -> but then it gets better.

2742.77 -> That can be many things.

2743.8 -> That could be a seizure.

2745.69 -> It could be a TIA.

2746.84 -> It could even be a small stroke.

2748.606 -> But if you have those kind of symptoms,

2750.23 -> you need to be evaluated by a physician,

2751.91 -> because that could be a warning sign of something bigger come.

2755.34 -> If you have that, that doesn't preclude you

2757.95 -> for being treated by what we do.

2759.96 -> So the question is, there are many things that

2762.11 -> can cause strokes that we talked about,

2763.94 -> and some of the risk factors.

2764.69 -> What about if you have a problem in your carotid artery and not

2766.86 -> just your heart?

2767.59 -> And what can you do about that?

2769.04 -> How do you know about it?

2770.26 -> So there are classic symptoms that can tip you off

2773.48 -> that you have a problem with your carotid artery.

2775.9 -> A very common one is something called amaurosis fugax.

2778.91 -> And that's described as you suddenly

2781.03 -> have a veil that drops across your eye

2782.89 -> and you lose vision in one eye.

2784.42 -> And then it recovers.

2786.23 -> That's a very common sign of a problem

2787.94 -> with your carotid artery on the same side where

2789.93 -> your visual symptoms are.

2791.43 -> If you have that, that's concerning.

2792.93 -> You need to be evaluated.

2795.4 -> The way you deal with narrowing in the neck,

2798.014 -> there are many things.

2798.93 -> You do medical management.

2800.22 -> So aspirin is good.

2801.96 -> Other antiplatelet medications are

2803.81 -> very good to help with that.

2805.374 -> If the narrowing is too severe and you're having symptoms,

2807.79 -> you need to get it fixed.

2809.32 -> Two ways to fix the narrowing are surgery,

2811.38 -> to kind of go and kind of Roto-Rooter it out, clean it

2814.44 -> up, sew it back together.

2816.21 -> That's call a carotid endarterectomy.

2817.83 -> It's a very good treatment.

2819.17 -> Patients that get it tend to do very, very well.

2821.26 -> The second thing is you could put a stent in it.

2823.26 -> carotid stent.

2824.32 -> That's a procedure that we also do.

2826.019 -> And that's where you come from inside the blood vessels

2828.31 -> and you basically put a little strut to open up the narrowing.

2832.75 -> Those are good treatments for problems in the neck.

2835.38 -> Some patients will have foggy thinking.

2838.27 -> Some patients will get light-headed.

2840.055 -> They'll get weakness when they're dehydrated.

2841.93 -> There are many symptoms that you can--

2843.34 -> Yeah, so the question is, are there

2844.94 -> tests you can do to look for narrowing in the blood

2847.064 -> vessels in the neck?

2848.38 -> There are.

2849.71 -> I would say for in general, for any medical test,

2853.18 -> it should be indicated.

2854.86 -> Because if you go looking for things

2856.47 -> and you don't have a symptom, it's

2858.514 -> not a good use of resources.

2859.68 -> And honestly, it will just turn up trouble

2861.47 -> that you didn't want to know about it.

2863.08 -> But if you are symptomatic, ultrasound is very good.

2866.91 -> CT scans are very good.

2868.48 -> MRI is very good.

2870.07 -> So talk to your doctor.

2871.304 -> So she's talking about what are the risk

2872.97 -> factors for having a stroke that you

2874.469 -> might identify by blood test?

2877.12 -> So the main things are in keeping with the major risk

2880.02 -> factors of stroke.

2881.42 -> So what is your-- are you diabetic?

2883.82 -> What's your sugar?

2884.74 -> What's your hemoglobin A1c?

2886.41 -> Are those normal range?

2888.11 -> What is your lipid profile?

2889.84 -> Also very important.

2891.63 -> Those are the kind of tests that most of us

2893.87 -> will, if we go see our primary care doctor, will look into.

2897.42 -> Things about your heart-- some patients will say, you know,

2900.3 -> I notice I don't have a normal heart rhythm when

2902.8 -> I put my finger on my pulse.

2904.11 -> Or I have palpitations, the sense that my heart's

2906.37 -> skipping a beat.

2907.327 -> Those are symptomatic things that you're not necessarily

2909.66 -> going to see by a blood test, but it's

2911.243 -> similar in terms of identifying a risk factor.

2914.315 -> [INAUDIBLE]

2914.814 ->

2917.56 -> So inflammatory markers right now,

2919.47 -> in terms of stroke risk factors, is not

2921.41 -> something that has been widely studied.

2924.14 -> And it'll be interesting to see if that does come out

2928.22 -> in the future as something that's important.

2932.496 -> Sir?

2933.488 -> When was TIA developed, and how much does it cost?

2936.96 -> tPA?

2937.833 -> tPA.

2938.68 -> So 1995 is when it was approved.

2941.077 -> I'm actually not sure when it was developed before that.

2943.41 -> tPA.

2944.03 -> Yeah.

2944.53 -> And I actually don't know what they charge for it now.

2947.162 -> I would say that anything what they

2948.62 -> charge for, it's very hard to know what it actually costs.

2952.03 -> Yeah, so it's a good question.

2953.43 -> So the question is, you know, there are a lot of delays.

2955.93 -> If you're going to be someone who's going to get tPA,

2958.82 -> there are a lot of delays in getting you to a hospital

2961.76 -> so that you're eligible for the tPA.

2964.06 -> And calling a paramedic, an ambulance transport,

2967.45 -> getting into the ER and being seen, and understanding

2969.7 -> what's going on, those things can add up,

2971.31 -> and what if that pushes you out of the window where

2973.435 -> you can get the medication?

2974.57 -> And so why not just train paramedics

2976.61 -> to identify stroke and give tPA in the field?

2980.61 -> That's a very good thought.

2982.069 -> But I would say there's a few things that we have

2984.11 -> to make sure we understand.

2985.27 -> Number one is not everything that looks

2987.46 -> like a stroke is a stroke.

2989.66 -> So seizures can look like a stroke.

2991.58 -> Low blood sugar can look like a stroke.

2993.83 -> Intracranial tumors can look like a stroke.

2996.34 -> A patient who's had a hypertensive hemorrhage

2998.39 -> in the brain can look like a stroke.

3000.35 -> And it is important to understand

3002.17 -> what you're dealing with, because although the risk

3004.4 -> of tPA is relatively low, if you massively expand

3008.03 -> the number of patients that you're going to treat

3010.517 -> and don't really understand what the diagnosis is,

3012.6 -> you will hurt a lot of people, particularly patients

3014.99 -> with tumors that are causing their symptoms,

3016.93 -> or who have already hemorrhaged.

3018.31 -> Because you're going to make them bleed more.

3021.21 -> But people have started to do what you're asking.

3024.56 -> So in Europe, for example, they have little lands

3027.35 -> that have a CT scanner in them.

3028.81 -> And they can drive these mobile stroke units around,

3031.55 -> scan the patient in the field, have a neuroradiologist

3034.16 -> interpret the image, give the thumbs up,

3036.22 -> and they can start to give the tPA in the field.

3038.94 -> So you can start to think about things like that.

3042.26 -> But that has been tossed around.

3043.76 -> But there are those limitations to it.

3045.54 -> And then just to clarify the numbers-- so fewer than 10%

3048.12 -> of patients are eligible for tPA because of the time

3050.63 -> constraints.

3051.77 -> And of the patients that get tPA compared to that do not,

3057.16 -> 30% will have a good clinical outcome

3059.01 -> and be functionally independent.

3060.46 -> So the question is, what is sort of the communication

3063.61 -> between the imaging, the people looking at the imaging,

3066.089 -> and the neuro-interventionalist who's

3067.63 -> going to go and try to get the blood clot?

3069.66 -> So it's very highly integrated.

3072.9 -> The people that do these procedures

3074.58 -> now come from a variety of backgrounds,

3077.19 -> the most common backgrounds being neuroradiologists

3080.03 -> like myself, neurologists who are trained in stroke,

3083 -> and neurosurgeons who are trained

3085.18 -> in stroke through endovascular techniques.

3089.03 -> So all of those groups are very savvy with neuro-imaging.

3093.07 -> It's very important that we understand

3095.15 -> the anatomy of the brain.

3097.11 -> And all those people that do this

3098.944 -> should have a very good understanding

3100.485 -> of the brain anatomy, as well as of the vasculature anatomy.

3104.73 -> The way it works at Stanford, and I

3106.27 -> don't know how it works everywhere,

3107.728 -> but I think most places try to do this.

3109.91 -> When we are made aware of a patient who's been flown in,

3112.9 -> our team is activated before they arrive.

3115.5 -> So I'm there at the scanner, waiting for the patient

3117.99 -> to show up.

3119.12 -> We clinically evaluate the patient.

3121.305 -> We are there when the patient goes right into the magnet,

3123.68 -> and we're looking at the images in real time

3125.513 -> while they're in the MRI or the CT scan.

3127.57 -> So that interpretation happens by us instantaneously,

3130.52 -> and we make a decision, by the time

3131.997 -> they wheel out of the scanner, whether we're taking them

3134.33 -> with us up to the cath lab or whether they're

3136.47 -> someone that's not likely to benefit

3138.02 -> from what we have to offer.

3139.81 -> Other places have-- they can look at imaging on their phones

3143.62 -> or their computers at home.

3145.346 -> There's a variety of set-ups.

3146.554 ->

3149.458 -> As a stroke preventative, can you give us your thoughts

3152.475 -> on blood thinners?

3154.71 -> If you need one, take it.

3156.488 -> [LAUGHTER]

3158.78 -> So the question is, what is the thought on blood thinners?

3161.95 -> So if you have an indication to take a blood thinner

3165.8 -> and your doctor tells you it's a good idea,

3167.99 -> then I think it's a good idea.

3169.787 -> But you've got to remember, everything

3171.37 -> that we do is not without risk.

3174.5 -> So should we all just take an aspirin?

3177.72 -> Should we all just be on Coumadin to prevent it?

3180.5 -> Well, a certain percentage of us,

3181.937 -> and it's not a small percent, is going

3183.52 -> to have a complication from that.

3184.92 -> And that could even be bleeding in the brain.

3186.9 -> And you want to just make sure you

3188.652 -> have a reason for the medication you're taking,

3190.61 -> because you are accepting a little bit of risk

3192.72 -> any time you put something in your body.

3194.82 -> The question is, is there a benefit

3197.03 -> to drinking red wine to clear out the arteries?

3199.28 -> There are studies that have shown

3202.07 -> moderate consumption of red wine to be

3205.03 -> good for your cardiovascular health.

3207.12 -> I do not know the literature on that,

3208.68 -> in terms of stroke prevention.

3209.93 -> In general, what is good for your cardiovascular health

3212.221 -> is good for stroke prevention.

3214.48 -> But I don't know the data as to whether having

3217.23 -> a glass of red wine a night, what's your decrease stroke

3220.475 -> risk from that.

3221.1 -> It's an interesting question.

3222.82 -> Good question.

3223.42 -> So there's two parts to the question that's being asked.

3225.753 -> One is, what are your options if you

3227.42 -> get to the hospital outside of the time windows we discussed,

3230.2 -> in terms of treating you, because you didn't recognize

3232.45 -> the symptoms, or for some other reason?

3234.482 -> And the second part of the question

3235.94 -> is, well, what about if there's a blood clot that's

3238.54 -> very far away, that's not something

3240.212 -> that's really safe for us to get to

3241.67 -> from inside the blood vessels?

3243.58 -> So first off, if you get to the hospital outside of that four

3246.92 -> and a half-hour time window when you get tPA,

3249.96 -> we can still offer you treatment from an endovascular

3252.9 -> perspective.

3254.75 -> That right now, there are good data for going out

3257.09 -> to six to eight hours.

3259.09 -> That being said, most major academic medical centers

3262.33 -> are now making their decisions based on the imaging

3264.76 -> profile that I talked about.

3266.56 -> So we have taken patients 12-plus hours out,

3269.73 -> because they get here, we do a scan,

3271.49 -> they've got a small stroke, they've got a lot of brain

3273.78 -> at risk, and there's a clot that we can get to.

3275.999 -> And I think increasingly, we're going

3277.54 -> to start to see more of that.

3279.39 -> So you do have options.

3281.41 -> Number two, what if you have a small artery

3283.624 -> that's blocked way out here?

3284.79 -> What can be done?

3286.76 -> There's a little bit of a gray zone.

3288.26 -> And I would say you have to be thoughtful.

3291.42 -> Because which artery is blocked?

3293.43 -> If you come into me and your symptoms are you

3296.58 -> can't speak because your angular artery

3298.587 -> is blocked on your dominant hemisphere

3300.17 -> on the left, that's going to leave you with a pretty

3303 -> significant neurologic deficit.

3305.34 -> A patient like that, we would actually

3307.12 -> consider taking to the procedure room

3308.76 -> and putting a microcatheter into that artery, as far as we can,

3312.26 -> and giving tPA to break up the clot.

3314.549 -> It's not safe to put a device out to pull the clot out,

3316.84 -> in my opinion, that far out.

3318.1 -> But there are options.

3319.66 -> If it's a smaller blood vessel, that maybe your symptoms are

3322.68 -> less profound, it's a cost/benefit.

3325.17 -> The risk of these procedures is not zero.

3327.5 -> And maybe the odds of you recovering some function, or it

3330.42 -> not really limiting what you do, you just say, you know what?

3334.074 -> We're going to keep your blood pressure appropriate place,

3336.49 -> and help you recover.

3337.722 -> That's a good question.

3338.68 -> So the question is among the patients with stroke

3341.8 -> that come in, what's the breakdown of men and women?

3344.96 -> So you know, there are many more patients with stroke that

3347.76 -> come into Stanford than I see.

3349.601 -> So the patients that we see are the ones who are really sick

3352.1 -> and have a blood vessel that's blocked that's really

3354.266 -> close to the brain.

3355.45 -> I've got to for us, it's pretty 50-50.

3358.14 -> We took care of a gentleman today,

3359.8 -> and yesterday we took care of a lady.

3362.38 -> And that kind of pans out.

3363.75 -> It's really pretty close to 50-50 now.

3367.671 -> One more.

3368.17 -> That's it, though, before I get yelled at.

3370.37 -> [LAUGHTER]

3371.238 -> Go ahead.

3372.54 -> Some hospitals offer stroke risk assessment.

3376.774 -> Does Stanford do that?

3378.437 -> That's a good question.

3379.395 -> Nick, are you here?

3381.296 -> Do you know?

3383.398 -> I don't.

3384.48 -> I don't know the answer to that.

3386.328 -> I live in Alameda, and the hospital there

3389.72 -> offers that quarterly.

3391.905 -> So--

3392.924 -> That's something that we should certainly look into.

3395.09 -> I don't know that we have a clinic that does that.

3397.84 -> We certainly have doctors that, you know, everyone

3400.11 -> in our network, if you come in and see your primary care

3403.39 -> physician in the Stanford network,

3404.88 -> you're going to get asked the questions that

3406.24 -> are going to be pertinent to your stroke risk.

3408.46 -> But someone who, you know, a specific stroke

3410.78 -> clinic about what your stroke risk is,

3412.48 -> I don't know if we have that.

3413.688 -> We can find that out for you.

3415.272 -> So.

3416.625 -> Thank you, Dr. Heit.

3418.43 -> My pleasure.

3419.08 -> Thank you all for coming.

3420.28 -> [APPLAUSE]

3421.452 ->

Source: https://www.youtube.com/watch?v=uLH18_y0EIY