 I'm Dr. Nitin Sobel and I'm going to talk on peripheral arterial disease. So typically, there are two broad indications for peripheral arterial disease. One is you get patients who are suspected to have arterial disease and you need to answer questions like, is it an arterial problem? If it is, then where is it? How much is it? What is the nature of disease? What is the status of co-laterals? How is the distilled runoff? So when you do the test at the back of your mind, we need to keep, we need to plan therapeutic options so that your test is more relevant as far as the clinical situation is concerned. There is another group of patients who typically bear an intervention has been done and you are asked to evaluate. This is becoming more common like post-operative, post-tentative or post-bypass grafts. We'll see some example. And then there is another group like, for example, evaluating sugar aneurysms, aneurysms, etc. We won't go into that today. Now, in a peripheral artery is always take a history, diabetes, smoking, very, very important, chlorocation, then pulpit all the pulses. And most importantly, at least an ankle to brachial index is very simple. You don't need such sophisticated tests. You need to do a pressure at a level of the ankle and at a level of the upper arm. So typically the ankle brachial index is more than one. Lower the ankle brachial index more is the severity of the ischemia. And this gives us a clue that, okay, something is definitely wrong and we need to look at it properly. We can also take segmental pressures in the upper thigh, lower thigh, upper calf, lower calf. And this also, it is a fall in the segmental pressure. This again gives us a clue as to where the disease is. Typically, as we know that if there's a fall at one point, the disease is likely to be proximal to that. So with this clues, we go ahead. Now, why is this important? This is important because a treatment of peripheral arterial disease is basically symptom-based and not anatomically based. That means at times anatomically, you can have a large lesions. Patient may not be symptomatic and then we don't treat them aggressively. Whereas sometimes anatomically lesion is small, but the symptoms are more and we need to treat them aggressively, especially when the patient is young. So remember, the anatomically again, we have, of course, we start with the aorta, the nileax and the femorrhoidinus. Some areas are difficult. For example, the aileax bifurcation can be difficult. The adacta canal can be difficult. The trafication of the pulmonary artery can be difficult. But we will see how to overcome these difficult areas. Always begin with the aorta in a longitudinal plane and in a transverse plane. Now transverse plane is again very important because sometimes the aorta becomes ecstatic or you might have focal aneurysm and you might miss on a part of the aorta. In fact, if you do it only longitudinally. So this again gives us a good idea about the walls of the aorta. The longitudinal again is very, very important because you can pick up atherosclerosis. You can look at pulsatory of the aorta, which can be a clue to several diseases. Then we can trace go right up to the bifurcation of aorta. The bifurcation of aorta is very important because that's a common site of atherosclerosis. It's a common site of aneurysms. That's where aneurysms start. So that is very, very important. For the aileax, I like to tilt the patient typically right side up for the right side, left side up for the left. This because usually I have a lot of gasses in this area and once you tilt the patient, then you can overcome this and you can actually look at the vessels in a much, much better way. And it's easy to interrogate this way also. For the femoralis, we like to externally rotate the leg and go medially. And it's very important to expose the entire leg, right? Expose the one in the area because looking at common femoral artery, the bifurcation of common femoral artery is again very, very important. So expose the patient properly. Do a good grayscale because very often you have plaques which will be missed if you directly switch on color Doppler. There is oversaturation of color. So I always prefer to do a grayscale whether it's peripheral artery carotid or of course whether it's veins. Typically, when we switch on color, when you are in the proximal portion of the SCFA or the proximal SCFA, we like to tilt the probe on this side until the beam on this side. Once we go to sleep, we like to tilt the beam on the other side. That's the normal color. We see red, blue, red, blue. This blue in the center of the red is because of aliasing, because of high velocities as we know. And the blue coming up intermittently is because of the reversal of flow. So peripheral arteries have a triphysic flow forward, one reversal of diastolic and then a forward diastolic flow. That's a classical of a peripheral artery disease. It's very often referred to as a multi-physic waveform. When we go to the adducta canal, sometimes it is difficult to see the adducta canal with a linear probe and therefore we might use a convex probe which has a lower frequency. Popliteal, we can ask the patient to lie down prone. Sometimes the patient has a bandage or is not able to lie down prone. We can just tilt them on one side and look at the popliteary artery from the sides. The bifurcation of the popliteary artery is very, very important to evaluate. So for the posterior artery, we can place it right from origin. We go medially of course. And usually the posterior artery will be accompanied by two veins on either side and it becomes very easy. And then once you spot it, you can go down right up to the medial malleolus or at the ankle joint. Sometimes it is easy to locate it here and then go up. So whatever very you want you can do. This is important, the tibia peroneal trunk. That is the anterior tibial artery which comes straight onto the probe. You do not have to do angle correction for that. And the peroneal artery which is deeper. These are both very, very important arteries. So here we are tracing the peroneal artery which as I said is relatively deeper and you can go right down. Fortunately, all three arteries have accompanying veins and that makes them easy to identify. We can look at dorsal spades again, which is again a continuation of anterior tibial artery. Again, typically a high resistance waveform. And then we can look at planters also. Nowadays, it is easy to look at planters. Typically, but it is difficult to look at toes as compared to the fingers in the abdomen. But we can go right up to the veins of the toes. Now, why is it important to look at aorta? Because very often the clue is in the aorta. You can have atrosclerosis, you can have thrombosis, you can have aneurysms, you can have dissections, anything. So if you miss this, then your examination goes haywire. There is an example of a patient who has got an iliac artery occlusion. There are a lot of collaterals. And again, is distal external iliac or the common femoral is filling through collaterals. So if someone is very new and sees this waveform and may feel oh, this looks like normal and can miss on an iliac operation. This is happening in practice. So the normal waveform in a peripheral artery is a triphysic waveform. We have a quick systolic upslope, one downward flow, one forward and then absent diastolic flow. And this is because of course, the limbs do not require blood flow throughout the kidney exactly. So that's when the blood is normal, of course, that's the basics. Then we have a laminar flow with a clear window. Moment there is a plaque, there is turbulence. We have the entire window filling up with multiple dots that tells us that there is something wrong here. But the velocities will not increase if the stenosis is not significant. Moment the stenosis becomes significant, associated with all filling of the window. We have increase in velocity, which is directly proportional to the degree of stenosis. So typically, if the velocity increase 100%, then we know that we are dealing with more than 50% stenosis. If the velocity is increased by 4 times the proximal segment, then we know it is 75%. So what is very important in all Dopplers is comparison with proximal segment. So because typically upstream 2 cm above the site of evaluation if the velocity is say 100 and then it becomes 200, we know it is 50% stenosis. So there are no shortcuts, we have to take multiple readings at multiple points. And you'll see why we do it in practice. So here's a classical day-to-day example. This patient has a gangrene and as we go down from into the femoral artery, as we go to the mid-portional femoral artery, we can see this aliasing and narrowing there on color Doppler and on pulse Doppler. Approximately we can see this monophysic waveform instead of a triphysic. This again tells us that something is going to go wrong, I think has gone wrong approximately. And rightly so at the site of stenosis, we can see that the velocities have increased to 400 cm per second from 70s or 80s, telling us it's more than 50%, almost like 75%, almost like 475% stenosis. So there again on color Doppler, you can see aliasing, you can see perivascular tissue vibration, telling us that this is a very, very significant stenosis. So further down in the same patient, we look at a popliteal, we look at the posterior tibial. We can see that there are severe atherosclerotic changes. There is hardly any flow on color Doppler there happening. And we traced right, and you can see that the flow is monophysic. It is classically tired as power Sicily, telling us that this blood has come through severely atherosclerotic stenosis. And that's what we saw approximately. And we traced it right up to the end. The anterior tibial arteries was partly part of the anterior tibial arteries are occluded. There are some collaterals happening there. And we can trace it right up to the foot. And when we look at it, our cell speed is again, we can see some flow, but the flow is dampened, monophysic or tired as powers. And that's the patient who had gangrene. We could see this flow right up to the base of the tooth. So that's a very important information which you can give to the clinician. Usually they want to know how the flow is, whether the plant planter arches are patent and whether this flow right up to the base of the tooth. That's another example against stenosis of the SFA with aliasing with very high velocities, almost 75% stenosis. So normally we have a dry phasic waveform. If it becomes biphasic instead of multiphasic, that means there is an arterial vessel of constriction or an obstruction distilled to the sampling site. If it becomes monophysic, then we again know that there is an arterial occlusion distilled to the sampling site. Or sometimes this can happen in a combined proximal and severe arterial disease. And if it is monophysic, tired as powers with increased time taken to reach a peak system, we know that there has been a proximal stenosis or occlusion. So that's a classical example of a tired as powers waveform seen in the distilled T-bellatory in a patient who had a poly-bellatory occlusion. Sometimes in ischemia, the traficity of course is lost because now the tissues want more blood to come before there is distilled vasotylation. And you can see a high diastolic flow in the peripheral arteries. Sometimes the waveform in the peripheral arteries become almost like a vein. That is because the arteries lose their tone, they no longer often in resistance. They become like a vein and you can see a continuous flow like this telling us that there is a distilled vasodilatation in ischemia. Then of course you can have thrombus. This video is not running. But typically when you have a thrombus, you see perivascular tissue vibration or the tissues around the thrombus vibrate. Because the blood comes with a lot of kinetic energy hits against the dead wall and the energy basically spreads to the surrounding tissue. And that's a classical way for which you get prior and distilled to the occlusion. Look out for colatils. That's a profunda artery which is dilated because the SFA is blocked. And that's an SFA which is totally occluded, but there's a very good colatils. And I was saying that if you have such good colatils and the patient is old and does not have much of symptoms. And if the physiological tests are fairly good, then one may not be very aggressive about such long-sablon occlusions also. Look at the extent of disease here. You can see a line of demarcation of ischemia and rightly so on. Now, colorably we can see that the profunda is quite okay, but the SFA is totally blocked. And that explains why this part of the thigh shows a good color. Cause of the disease are common, of course, is atherosclerosis, diabetic atherosclerosis, typically with lot of calcification in the wall. Burgers are not very common in the lower limb, but occasionally, of course, we see typically the arteries are markedly thick walled. And they look like an almost like an umbilical arteries. Off-lead, we have been seeing COVID-19 presenting as lower limb ischemia atherosclerosis because of the multiple factors which are active in a COVID situation. Here's an example of a young person who came with from Rajesh's clinic, who came with ischemia in the leg. And he had symptoms which were there only for few hours. He had a total occlusion of the SFA and most subsequently a COVID positive case. So normally, there are a lot of interventions which are done, angioplasty is done, STEN support. We can have thrombolytic therapy, which is again becoming popular. We can have grafts. So let's see just some examples. That's a patient who's got an autofumeral graft and you can see that on the right side it is blocked. And it's very important whenever a patient has come to you after intervention to look at the history to find out what sort of a graft or scent has been put because otherwise examination can be difficult. Venus grafts are very difficult to evaluate because they're very thin and very often if they're normal, they collapse when you put pressure on your probe. Venus grafts have valves. There are two types as we know one is in situ and one is reverse vein graft. But it's very important to monitor Venus grafts. Then that's a stent and you can see that there is a stent stenosis. That's a perivascular tissue vibration, mosaic color telling us that there is a segment of stenosis. We can have patients after trauma coming with edema and this is a classical compartment syndrome. What we see here is a pan reversal of flow in the femoral artery and the proximal portion of the posterior artery. This is very diagnostic of a compartment syndrome, telling us that there's a very high resistance. That's another example of a compartment syndrome. On the left side, on the right side, we can see a normal trapezoid waveform in the femoral artery. On the left side, we can see a pan reversal of flow, telling us that there is soft tissue removal. You can see some fluid there and you need to do face shot on me and release the pressure. Sometimes after orthopedic surgery, the patients lose their pulse. The clinician wants to know is it compartment syndrome or is it a block here? For example, we have a tibia peroneal block and the patient had to be opened up again. Sometimes after trauma, patients may have vasospasm, particularly which may last for quite some time. There's a young girl who had a trauma of the actually of her fingers and there was a vasospasm which lasted for quite some time. But after some time, when we looked at the radial artery, it opened up and we see a good taste of the flow. So at the end of it, give a chart and answer the fundamental questions that is it an arterial problem? Where is it? How much is it? What is the length of the legion? What is the status of colateral? What is the sort of disease? And what is the status of distiller? So all these points are very, very important for the clinician to make a decision. Thank you so much for your attention.