PERFORMING ENDOVASCULAR SURGERY: New Minimally Invasive Approach to Treating Vascular Disease

The most attractive treatment option for many patients with certain circulatory disorders may be the newest technique available—endovascular surgery. In the summer of 1999, University Hospital became the first hospital in Suffolk County to offer this cutting-edge treatment of vascular disease, and give patients the opportunity to avoid conventional open surgery.

Endovascular surgery is minimally invasive, as the incision is just large enough for the surgeon to insert a catheter (thin tube) into the blood vessel, through which instruments and devices can be inserted to treat diseased blood vessels, clean out blocked vessels, or deliver clot-dissolving medications directly at the problem area. All the surgeon's work is done from within the vessels themselves (endo-, within + vascular, vessel), with the aid of newly developed technology and instrumentation.

Because this surgery involves a smaller incision compared with that used in conventional vascular operations, and because it does not interrupt blood flow to the legs or other vital organs, it causes less disruption of the patient's physiology, or vital processes. Consequently, the hospital stay is usually much shorter and the patient's recovery much faster.

Given that these less invasive methods have been sought for decades, endovascular surgery—originally developed in the mid-1980s—is now a rapidly growing field of therapy. It may be used independently or in combination with conventional operations for treating vascular disease. At present, nearly every vascular bed in the body can be approached intraluminally (from within the vessels).

With the recent advent of several endografts, or "internal bypass" grafts, the minimally invasive techniques of endovascular surgery have been applied successfully to treat aneurysmal as well as occlusive atherosclerotic disease—that is, to correct circulation problems in damaged or blocked arteries without having to resort to open surgery. Since 1999, when the Food and Drug Administration (FDA) approved the use of endografts, a large number of patients nationwide have had successful repair of their abdominal aortic aneurysms (AAAs) without a major open operation.

Endovascular Stent Grafting

Multiple studies conducted in the United States and in Europe have shown excellent short- and mid-term results with the use of endografts for the treatment of AAAs. So far, patients treated with this method have fewer complications at the time of surgery and, when compared with the traditional open surgery for AAA repair, patients have similar survival rates at five years. These very promising results have prompted application of the endovascular method to treat aneurysms in other areas of the body. In 2005, the FDA approved endograft use for the treatment of thoracic aneurysms, after studies showed it to be safe and effective.

The area of largest investigation is for AAA repair. The use of endovascular technology is being compared to standard therapy in clinical trials, and may be particularly beneficial for patients so ill and infirm that the risk of a conventional open repair is excessive.

The abdominal aorta is the main artery that supplies blood to the stomach and legs; an aneurysm, which is potentially life-threatening, is an enlargement or bulge of an artery caused by a weak artery wall. Indeed, AAA is the 13th leading cause of death in the United States, claiming over 15,000 lives annually. In this country alone, more than 190,000 AAAs are diagnosed each year and 45,000 patients undergo surgery.

Aortic stent grafting provides to offer a simpler and safer alternative to open abdominal surgery in the treatment of AAA. It may prove to be one of the biggest advances made in vascular surgery, as it has the potential to save many lives.

Candidates for the new treatment are patients diagnosed with AAAs, as well as others abnormalities of the abdominal aorta, such as ateriovenous fistula (abnormal communication between the artery and a vein) and certain types of aortic blockages.

The traditional approach to AAA repair involves operating on the abdomen, opening the aorta, and inserting a graft—a slender fabric tube—through the middle of the aneurysm, which is then sewn in place. Because the conventional operation generally involves a long abdominal incision and a seven- to ten-day hospital stay, the new endovascular procedure offers significant advantages. This minimally invasive surgery, which can be performed using regional or even local anesthesia, often allows patients otherwise too ill for the conventional operation to be considered for AAA repair.

Endovascular stent grafting enables physicians to accomplish the repair without resorting to open surgery. The stent graft, a self-expanding device, is similar to the traditional Dacron graft but is mounted on a metal stent which helps it to maintain its original shape while conforming to the shape of the aorta. Special hooks and barbs at the ends of the endograft allow it to anchor itself to the inner wall of the blood vessel.

The stent graft is collapsed and loaded into a tube-like delivery system. The arteries in the groin are exposed by the surgeon using two small incisions. A wire is then threaded up from within the blood vessel to a point beyond the diseased part of the blood vessel. This wire acts like a monorail on which the delivery system and other catheters and stents can move up and down the blood vessel.

The delivery system carrying the stent graft within it is threaded up the artery over the wire lying within the blood vessel, and is guided by fluoroscopy (x-ray imaging) into the aneurysm. Once inside the aneurysm, the sheath of the delivery system is gradually withdrawn, allowing the stent graft to re-expand to its original size and anchor itself onto the inside of the arterial wall by the hooks and barbs at either end.

Some stent grafts require a balloon to be inflated within them to push the anchoring hooks into the wall. Accurate placement is essential because the arteries to the kidneys are close by and should not be covered. Since the procedure is minimally invasive, the patient is usually able to eat the same day, walk the next day, and go home in two or three days.

Several types of stents and stent grafts are available and can be used for various procedures. Most of the stents function as supports for the arterial wall and hold blocked or narrowed arteries open after balloon angioplasty. The purpose of the aortic stent graft, on the other hand, is not to brace the artery open, but to create a new passageway for blood, allowing it to bypass the weakened/diseased area. Although this newly developed stent graft is now used only for the repair of AAA, it is anticipated that in the future, the procedure will be used to repair aneurysms at multiple locations.

Our surgeons are skilled not only in the use of aortic stent grafts but in other endovascular procedures as well. These include balloon angioplasty, clot dissolution, and stenting of arteries.

Angioplasty with Stenting

Balloon angioplasty, a procedure which increases the amount of blood flowing through a narrowed area by disrupting and stretching the plaque, has been around for many years. It is successfully used in coronary arteries, renal arteries, and in some of the larger arteries of the body. It is, however, less successful in small leg arteries and in completely-blocked arteries.

To support the work done by an angioplasty balloon that opens up a blocked vessel, the stent—a wire "cage" or "frame"—is placed inside the vessel at the site of the problem. Under some circumstances, the stent increases the durability of angioplasty, yet adds little to the complexity or risk of the procedure.

Our vascular surgery team has been performing angioplasty with stenting as part of open reconstructions and also as a separate procedure. Now, with the latest technology, we can provide the new endovascular stent grafts as well.