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Insights from the world's best medical minds

Dr.Nishit Choksi

Nishit Choksi, Director,Vascular Interventions WM Beaumont Hospital,USA,Renal Atery Stenting
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Dr.Nishit Choksi

Director,Vascular Interventions

WM Beaumont Hospital,USA


Take home message here would be that if somebody has blockage in the renal arteries and if there is severe recent onset accelerated severe malignant hypertension/pulmonary edema/unstable angina, these patients would benefit a lot from renal artery stenting if appropriate workup with hemodynamic assessment of these lesions have done.


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Dr.Nishit Choksi

I thought that I will deliver few thoughts and teach to the delegates and in the bargain actually I learnt a lot myself. I was thoroughly impressed with the physicians who take care of complex vascular problems in India with very limited resources. Having said that let me give a synopsis of my topic. I have had four topics during this conference and I will give you short synopsis. My first topic was about renal artery stenting. As you know in 1990s and 2000, the renal artery stenting increased in numbers but then a flow of studies came out suggesting that it will not help and therefore it has been on the vein if the renal artery stenting is concerned for treatment of hypertension but there have been few observations (01:00) that has now led to the surgeons of renal artery stenting. There is a study from San Juan, Puerto Rico and my own experience of 76 patients we have done renal stenting in patients who had severe stenosis but they were concerned with some kind of hemodynamic assessment such as FFR and IVUS. In the previous studies, these things were not done and therefore any patient with severe stenosis we stented it hoping that we will help the hypertension and in these patients the stenosis had nothing to do with hypertension and therefore the results were subset. Although some of the trials had lot of fallacies in it which came out later on. For example, in the CORAL trial which was a landmark trial, later than in the study they decided that hypertension was not a criteria (02:00) to do renal artery stenting. They also said that 60% blockage would be all right to do renal artery stenting. Now when that 60% lesion would have any significant impact on the vascular bed of the renal arteries unless it is proven by FFR and/or by what we call hyperemic systolic gradient given from the coronary arteries. We used to do a lot of coronary stenting and we realized after a while that this did not help and then few years ago trials came out that showed that if you did FFR in 60% blockage or an 80% blockage, if the fractional flow reserve was positive and if it was less than 0.8 in that patient we would impact positively with stent and the same analogy works for the renal arteries also. (03:00) In my series of 76 patients and another series of 200 plus patients, if these patients were followed hemodynamically then the outcomes were excellent. So take home message here would be that if somebody has blockage in the renal arteries and if there is severe recent onset accelerated severe malignant hypertension/pulmonary edema/unstable angina, these patients would benefit a lot from renal artery stenting if appropriate workup with hemodynamic assessment of these lesions have done. So that would be the take home message. Moving on to the second topic is about what they are called Blue Toe Syndrome. Many times we see in livedo reticularis where the toes get blue due to embolization of cholesterol crystals (04:00) usually from heavily diseased aorta of the iliac arteries. It generally happens after the procedure. There is really no treatment for that and these patients will have excellent distal pulses because the emboli are microemboli. If it is just in the feet, they will resolve spontaneously, you may use vasodilator, but the key is not to use anticoagulation. But though the situation there will be unilateral blue toes and absence of pulses, in that situation thrombolytic therapy plays a very important role and that was the gist of my topic that is thrombolysis important and does it play a role in Blue Toe Syndrome. Yes, in the certain subset that I just mentioned if they do not have pulses, sudden onset of Blue Toe Syndrome, severe pain, in this case is usually there is an embolus from a lesion within the iliac artery, (05:00)SFA, popliteal artery that goes down and these patients respond very well to lytic therapy because there were fresh thrombi. I generally advise my students not to do thrombectomy particularly if the motor sensory function is intact because when you do thrombectomy in this situation, you may embolize the clot into the different digital vessels and it is very difficult to take care of that. Of course if there is any evidence or sign or symptom of motor sensory loss, then lytic therapy can be done but you should do a manual thrombectomy first. A lytic therapy takes 2 to 4 hours to work and hence there is some time gap and if you have the time, if you have the luxury of time, then just lytic therapy alone will work wonders for these patients within 2 to 4 hours the blue toes syndrome, the blue toes would become pink again and the pain resolves completely and the patient feels better (06:00). The patients can actually go home next day. My next topic was mesenteric artery intervention. Mesenteric arteries generally do not cause problems because they are plethora of connections, collateral circulation between the celiac access, the superior mesenteric arteries, the inferior mesenteric arteries and in acute situation where embolus comes from only from the heart then it is catastrophic problem. Acute mesenteric ischemia usually is a surgical problem, but on occasions, there will be what we would call chronic mesenteric ischemia. Chronic mesenteric ischemia is due to severe stenosis of the mesenteric arteries causing severe abdominal pain. People are afraid to eat that they will lose weight. They will look like a cancer patients. So these patients would benefit a lot (07:00) from percutaneous interventions such as angioplasty and stenting. It is also important to note that mesenteric ischemia can present in many different ways, nausea, vomiting, bloody diarrhea, they can present in inflammatory bowel disease and many a times we climb up the wrong tree looking for gallbladder problems, looking for ulcers in the stomach, but after all the workup is negative, we then try to look for mesenteric ischemia, mesenteric artery stenosis or celiac artery stenosis. The success rate of doing mesenteric intervention percutaneously is very high. All these years the hallmark of treatment, the benchmark for treatment was surgical and bypass surgery. It works very well, but unfortunately the morbidity is in the range of 25-30%. The mortality rate is 8-12%. So on one hand long-term results are good, but on the other hand the (08:00) immediate postoperative timeframe, high morbidity and mortality and therefore now to treat chronic mesenteric ischemia, endovascular treatment first. Now yes there is high rate of restenosis, but on the other hand just like in the renal interventions, if we chose the patients right, if you use the size stent by doing IVUS in these patients and possibly covered stents, the chance of restenosis would be very, very low. Now usually over the years, we have recommended that we only treat patients who are symptomatic, but there are subset patients who have severe mesenteric artery stenosis they may have no symptoms, but you may need to do the interventions. There are two subsets, the patient with severe three-vessel critical stenosis which means celiac artery, superior mesenteric artery and the inferior mesenteric artery (09:00), all three vessels have severe critical stenosis, then it may be reasonable to do interventions because in the long-term follow-up a lot majority of these patients with severe critical three-vessel disease when they were followed up for 5 to 6 years, they develop bowel infection, high percent, more than 80% and that as a result of bowel infection. So to prevent further catastrophic event, we should consider doing intervention even if they are asymptomatic. Another subset of patients who would benefit from mesenteric intervention in patients who has severe disease are patients who are going for some major abdominal surgery, because as you all know, as you are all aware we have encountered these patients, they become hypotensive during surgery and perioperatively and a result of hypotension they get acute bowel ischemia, which equals that (10:00) large majority of the patients die and therefore as part of the workup prior to a major abdominal surgery, a CT angiogram should be done and in the right subset of patients diabetic, smokers, PAD, coronary artery disease, if they have severe three-vessel disease, celiac artery disease, superior and inferior mesenteric artery disease, they should be opened up prior to such interventions prior to this surgery. Because generally we use bare metal stent an elective abdominal surgery can be done within 4 to 6 weeks of such intervention. You do have to wait 9 months to a year like we have to do for drug-coated stent. So that is the take on mesenteric ischemia. One more thing, in the past we were taught that it takes two-vessels at least to be severely stenosed to have symptoms of mesenteric ischemia such as abdominal pain, nausea, vomiting, (11:00), but I have a series of patients not just me, but lot of people single-vessel disease can cause such symptoms, abdominal pain, diarrhea, and after fixing them instantly the same evening, the symptoms resolve. So be cognizant that the patients may have severe mesenteric artery disease and hence they may need to be opened up if they have such symptoms. Finally to wrap up I have a talk on iliac vein stenosis. Lot of patients we see on an outpatient basis who have leg swelling and over the years they were treated for heart failure, but it may have nothing to do with heart failure. We treated them for many other things but iliac vein stenosis. There are two kinds of iliac vein stenosis, thrombotic and non-thrombotic. There is something that we call May-Thurner syndrome or nonspecific iliac vein stenosis (12:00) wherein the iliac artery compresses the iliac vein and over a period of time can cause blockage of the iliac vein and this results in leg edema, leg claudication, ulcers, and ganglion, very difficult to walk. So these patients should be treated. Then iliac vein stenosis can also be a sequelae of DVT. These patients commonly have deep vein thrombosis and hence they have retrograde reflux of the valves in the greater saphenous vein and the deep venous system which causes leg edema, skin changes and ulcers. Now, the key take home point in iliac vein stenosis is that the diagnoses is made #1 by clinical suspicion and #2 not by venogram as they are going to be missing more than 50% of the (13:00) patients. Diagnosis is made by IVUS, intravascular ultrasound. It is the diagnostic tool for iliac vein stenosis. Treatment is very simple. You stent this patient with wall stent, one must extend the stent into the inferior vena cava, it should come out at least 2 to 3 cm into the inferior vena cava otherwise the stent will migrate and you will have poor outcome. So to wrap it up great conference, I learnt a lot myself. Great cases are presented.



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