The annual VEITHSymposium (veithsymposium.org) took place November 18-22, 2014, in New York City, New York.
You are coming from the perspective of an “endocompetent” vascular surgeon. Can you share your thoughts on the treatment of chronic total occlusions (CTOs) in critical limb ischemia (CLI)?
I think that the pendant has swung too much towards endovascular at this point. Too many of us are jumping on the bandwagon to say that all limb salvage procedures, and all patients who have claudication, are candidates for endovascular procedures. However, there are a substantial number of patients where endovascular procedures may not be the most suitable, or at least the most durable, procedure for them. In general, people don’t want to hear about going under the knife when they can have a puncture instead. On the other hand, going under the knife in some circumstances may be the best thing for these patients in the long term, because the cases that I am referring to are very complex. These patients have a very long blockage in the superficial femoral artery that extends into the popliteal artery, and the only runoff is via the small arteries in the leg. The results are much more durable and successful in terms of the patency of the reconstruction and also in limb functionality with a bypass. Of course, the bypass entails going under the knife, as we say; however, these procedures are have a very high, immediate, and long-term success rate, especially if the patient’s vein is of good quality. Here is the critical issue, whether the vein is usable. If the patient has a good vein and has extensive atherosclerotic occlusive disease in the lower extremity, he or she would do much better after undergoing a bypass with a good vein than the angioplasty with whatever method is being used as an adjunctive procedure, be it atherectomy or a drug-eluting stent or balloon. Let me note, however, that I am speaking mostly from experience on non-drug-eluting endovascular adjunctive procedures. It is only recently that the FDA approved drug-eluting stents and drug-coated balloons, and I personally don’t have extensive experience with either treatment. To clarify, the majority of patients today that have claudication or critical limb ischemia are still candidates for an endovascular-first approach. That is what I do in my practice. Ninety percent of my patients undergo endovascular procedures. Fifteen years ago I was considered one of the most aggressive interventionalists. I ran a study for bypass on femoral-popliteal disease, and at some point, I had difficulties finding patients for the study, because I was doing so many angioplasties and so many interventions with acceptable results. So I am not saying that I don’t do endovascular procedures or I am against them. I am saying that some patients with very extensive femoral-popliteal disease are better treated with bypass for the long term, if they are healthy enough and a good vein is present.
What is the likelihood that such a patient would have a usable vein?
Over 80% would have a usable vein. We use the great saphenous vein, ipsilateral to the symptomatic leg. Most of the time, it is possible to find a vein or use some strategies to take another piece of vein from somewhere else and put them together. We may use that same vein in a reverse position, or in a position we call translocated, since there is sometimes a mismatch between the proximal and the distal end of the vein. In those cases, we try to use the larger proximal segment of the vein for the superficial femoral artery as an inflow site, and use the distal portion of the vein, the smaller vein, to the small artery.
What kind of patency would you expect from a bypass and how does it compare to endovascular procedures?
Up to one year, the results between the two procedures are not much different, because some of the drug-eluting stents have a patency rate of over 80% at two years. So even up to two years, the results are very much the same. But I am not talking about a short segment occlusion in the superficial femoral artery. I am talking about more extensive disease. If there is more extensive disease within a subgroup of patients, after a year, the results are clearly in favor of a bypass. However, when we make a decision and offer choices to our patients, we have to include certain things in the decision-making process: their life expectancy, how they feel about perhaps first undergoing an endovascular approach, but recognizing that they would need to have other procedures, because an endovascular reconstruction won’t last that long. In informed consent, we must include not just patency of the reconstruction, but the patient’s overall conditions and feelings about procedures. There is a great fear of surgery among human beings. Some people feel surgery is the culprit, the disease, not the solution. We all associate surgery with pain, immobility, with getting out of our routine or work, and not being able to function properly. But, in my experience, patients are most afraid of pain. They feel that if you just do a puncture, there will be no pain. Anything related to laser is very popular among the lay population, because they feel that laser is painless. However, if you consider the patient and spend an extra period of time explaining the risks, benefits, and alternatives, many will decide that a bypass, for extensive occlusive disease, is probably better than attempting a balloon angioplasty or any other endovascular technique.
What kind of recovery do bypass patients undergo?
Patients will have some swelling of the leg and some pain. One of the major issues with the bypass is that we continue to perform long incisions for harvesting the vein, although a short incision can be done using endoscopic instrumentation. Most of us continue to make those long incisions and you can end up with wound complications as a result. Up to 8% of patients may develop some wound complications, which is very annoying for the patient, because it may take some time to heal. All bypass patients will have some swelling that takes a few months to dissipate. Bypass is not a one-shot deal either, because patients need to have follow-up in order to maintain over 80% patency at 5-10 years. We need to see these patients and do follow-up duplex scans at certain intervals. In the first year, it is every 3 months, then every 6 months, because these veins do develop stenoses, whether at the hookup with the artery at the proximal level or the distal level, or along the vein itself. Occasionally the artery itself will narrow. Once you do a bypass on a patient, basically, you are signing a contract for life. Yet it is the same with endovascular techniques. What we are doing is tricking the disease; we are not solving the intrinsic problem of the patient, which is atherosclerosis or a reaction to what we have done, i.e., intimal hyperplasia. We can ameliorate this problem by giving patients statins, and by making sure their blood pressure and diabetes are controlled. All of that has an overall effect. But the main issue of atherosclerosis and occlusive disease — this is something we have not yet solved. The options we have discussed do have value for symptomatic patients, but are temporary measures only, and these patients need to be carefully followed.
If there is an issue in the future, what procedure do bypass patients undergo?
Most patients will undergo endovascular procedures for maintenance, especially if we detect problems before they thrombose. Once the veins thrombose, then salvage of the graft is very diminished. If you detect it while the veins are still in a failing state, then the results are excellent.
Eighty percent patency at 5-10 years is very good compared to endovascular procedures.
Yes, but this is an operation versus a minimally invasive procedure. You do have to discuss these options with the patients and ask them what they prefer. Also, depending on the experience of the interventionalist, an attempt at opening a very long occlusive artery can be problematic. If the lesion goes into the popliteal below the knee, sometimes situations occur, unfortunately, where you worsen the patient’s condition, because you can damage collaterals or extend the process distally.
There are things you can do to enhance an endovascular reconstruction. We did a study on thrombosis and its relationship to volume flow in the popliteal artery.1 If the volume flow was measured at over 100mL per minute, the rate of thrombosis at 30 days was about 2%. If the volume flow in the popliteal artery was less than 100mL/minute, the rate of thrombosis was significantly higher, >10%. If you already did an intervention, measure volume flow, and it is low, what can you do? It is an indication that perhaps the operator should be more aggressive about opening an additional distal vessel to improve the flow and go beyond that benchmark.
Any final thoughts?
The future is bright for endovascular procedures, because they are rapidly developing. Every month, a new device comes along and a new medication to diminish intimal hyperplasia is being evaluated, and the material becomes more sophisticated. The profiles of the stents get smaller. The radial force increases. It is an evolution, and the materials for endovascular procedures are far better now than only 5 or 6 years ago. As we continue advancing in the endovascular field, we will see less and less bypass procedures performed.
Yet we are not there yet.
For some patients, we are not there yet, and not all patients are candidates for endovascular procedures, and not all patients are candidates for bypass. We must use our judgment and what is in the literature, which supports, for very long lesions in the superficial femoral artery, particularly when the lesions extend into the popliteal artery below the knee, a bypass operation in healthy patients that can withstand an operation and have a good saphenous vein.
- Ascher E, Hingorani AP, Marks NA. Popliteal artery volume flow measurement: a new and reliable predictor of early patency after infrainguinal balloon angioplasty and subintimal dissection. J Vasc Surg. 2007 Jan;45(1):17-23; discussion 2