Carotid Stenosis: Etiology, Examination, Diagnosis

00:01 Welcome back.

00:02 Thanks for joining me on this discussion of carotid stenosis in the section of vascular surgery.

00:10 Carotid stenosis is a very common disease and there are some risk factors, particularly puts you at higher incidence.

00:17 For example, smoking.

00:19 In fact, smoking is a high-risk factor for most vascular diseases.

00:24 There is some association with increased alcohol intake and, of course, like any peripheral vascular disease, when one has one peripheral vascular disease, one is at a higher association for another.

00:38 In this situation, patients with coronary artery disease also may have carotid disease.

00:43 This is an important distinction, because when patients have coronary artery disease, also think about working them up for bilateral carotid diseases.

00:54 Let's discuss the pathophysiology of carotid diseases and atherosclerotic plaques.

01:01 Here's a depiction of a common carotid bifurcation.

01:05 It's, of course, situated in your neck.

01:06 You can feel your own carotid pulses.

01:09 Atherosclerotic plaques are dense in lipids and they usually occur at the carotid bifurcation.

01:17 This is particularly because, at the bifurcation, laminar or straight-line flow becomes turbulent.

01:24 And as turbulent flow occurs at the bifurcation, it perpetuates worsening of the atherosclerotic plaque.

01:32 At some point, the plaque becomes so thick that it actually narrows the lumen of the vessels.

01:38 That's when you become symptomatic.

01:43 What are some common findings of carotid stenosis? One might actually hear a carotid bruit.

01:48 When you listen to a patient who has a carotid stenosis, the carotid bruit actually sounds like, well, turbulent flow, as I previously described.

01:57 Some patients will also describe transient ischemic attacks, also known as TIAs.

02:04 In these select patients, it's a warning sign.

02:07 Patients may have intermittent stroke symptoms that are self-contained.

02:12 They may have completely resolved by the time the patient even presents to your office or the emergency room, but don't lose these patients to follow up.

02:21 They may actually have significant carotid disease.

02:27 This is a depiction of a curtain drawn down or a shade over a window.

02:32 And that's a classic description of amaurosis fugax.

02:36 That's the transient monocular blindness that's associated with plaques.

02:41 And those plaques may be distributing themselves into the ophthalmic artery.

02:45 Next.

02:46 Patients may actually have CVAs or stroke.

02:49 CVA stands for cerebrovascular accidents.

02:54 This is most likely due to portions of the atherosclerotic plaque breaking off and being embolic.

03:01 Also, when the channel is so stenotic that the flow is inadequate, one may actually have a broader distribution ischemic stroke.

03:10 Labs are unlikely to be helpful to you, but it is very important to screen for carotid disease when you have high suspicions.

03:18 How do we screen for carotid disease? I’ll give you a second to think about it.

03:25 That's right.

03:26 Carotid duplex ultrasonography.

03:29 As with all ultrasounds, the results and accuracy of these tests are heavily operator dependent.

03:35 Let's say the clinical scenario is a patient who presents to your office.

03:39 They describe symptoms consistent with TIAs or amaurosis fugax.

03:44 The next step of management will be obtain a carotid duplex ultrasound.

03:50 Duplexes are helpful not only because they give you anatomic information, but more importantly, for stenotic vessels, they give you velocity information.

04:00 Recall, flow through a smaller diameter is usually at higher velocities.

04:06 That’s simple physics. A certain velocity, as described as centimeters per second, is indicative of a percentage of carotid stenosis.

04:16 This is an approximation of course.

04:19 Angiography.

04:21 For many years, angiography was the gold standard.

04:24 I'm talking about the invasive interventional angiography, of course, not the spiral CAT scan angiographies.

04:32 In this representative invasive angiography, the arrow points at an area that’s most likely representative of a plaque.

04:39 Note, it's very close to the bifurcation.