Surgical Therapy in PAD

Surgical therapy has been used to treat patients with peripheral arterial disease (PAD) for many decades. With this long experience, vascular surgeons have learned a tremendous amount about the likelihood of success for individual operations, the durability of these procedures, and which patients are most likely to benefit from surgery. In addition, the risks of the procedures and the consequences of failure are also fairly well understood. It is important to understand that surgery does not cure the patient of PAD. Surgery merely provides more blood flow to the leg involved, but the PAD remains. Operations for PAD can be divided into two groups: endarterectomy and bypass grafting.

Endarterectomy works best for narrow areas or complete blockages in the body that are in the pelvis (iliac arteries) or groin (femoral arteries) and are short in length. The surgeon actually opens the artery along its length and uses tools to peel away the diseased area of the artery. The surgeon will then close the artery with a patch to make the operated artery wider and less likely to narrow from scarring in the months following the surgery. This procedure is now almost always limited to use in the groin area, because angioplasty and stenting are preferred treatments for the pelvic area. Since the surgeon must open the artery along its length, the incision is often fairly large. This technique does not work very well for smaller arteries farther down the leg and is not often used in those areas.

Bypass grafting is routing blood from above an obstruction in the artery to below an obstruction, and is frequently used to treat PAD and its more severe form, critical limb ischemia. Bypasses are called by the combined names of the artery above the blockage and the artery below the blockage. Examples are aortobifemoral (blood routed from the aorta to both femoral arteries), femoropopliteal (blood routed from a femoral to a popliteal artery), and femorotibial (blood routed from a femoral to a tibial artery). Since bypass grafting is a rerouting of the blood flow, a tube (graft or conduit) is required to carry the blood. The most durable conduit depends on where the bypass graft is located. For bypasses in the pelvis, artificial material works best because these are large arteries and there are no large veins to use. For bypasses down the leg, artificial conduit is adequate as long as the bypass graft does not have to cross the knee. However, bypasses below the knee work best with the patient's own vein, preferably the saphenous vein (the same vein from the inner leg that heart surgeons use to bypass the heart blood vessels).

Several things about bypass surgery need to be kept in mind:

1. Placing a bypass permanently changes the artery structure of the leg. That often means that if the bypass clots off, the patient may have worse symptoms than before it was placed. This could include symptoms so bad that without another bypass, the patient may require an amputation.
2. All bypasses have an expected patency (time of continued function as the bypass remains open) that at best is measured at 5 to 15 years. The best results are for bypasses in the pelvis. In general, the farther down the leg a surgeon has to go to bypass the obstructions, the shorter the patency of the bypass.
3. Bypasses are big operations in older patients with PAD. That means that they have some risks in addition to clotting off and not functioning. These risks include death from various causes, most often heart attack (which usually occurs in the days following the operation). In general, the risk of death is one in twenty; younger patients have lower risk and older patients may have greater risk.
4. Leg complications are more common, including infections and breakdown of incisions. The vast majority of these will eventually heal, but it may take weeks and months. Many patients will have swelling of the operated leg, which can be severe. The swelling often gets better with time, but mild permanent swelling is common.

The most important thing for patients to understand is that leg bypass surgery is not like other types of surgery. The surgeon and the patient will develop a lifelong relationship. That is because the bypasses have a much better chance of working long-term if the patient continues to see the surgeon from time to time in clinic. The bypass must be monitored with physical examination and ultrasound to make sure it is not narrowing in areas. The narrowing can occur without any symptoms. If the surgeon is able to detect this narrowing, it can usually be repaired with either balloon techniques or a small surgery. If it is allowed to progress and the bypass fails completely, then the patient may lose the leg or require a large operation. Patients can help enhance the success of their surgery by following their doctors' orders, taking all medications, and ceasing tobacco use.

About the Author: Mark R. Nehler, MD, is a vascular surgeon at the University of Colorado Health Sciences Center and the director of the surgery training program. In addition, he was an original member of the Board of Directors of the Vascular Disease Foundation.

Illustrations for this article are copyrighted by the Society for Vascular Surgery and used with their permission.