The Xience is among several drug-eluting coronary stents used off-label in a study to improve high restenosis rates lesions below the knee.
April 21, 2010 – More than 100,000 amputations are performed each year in the United States on patients with critical limb ischemia (CLI), the most severe form of peripheral arterial disease (PAD). Interventional radiologists have found a subgroup of patients with CLI may avoid amputation through the use of drug-eluting stents on the smaller arteries below the knee, according to a recent single-center study.
"Drug-eluting stents are an emerging technology that offers hope to PAD patients with critical limb ischemia and freedom from major amputations,” said Robert A. Lookstein, M.D., an interventional radiologist and associate director of the division of interventional radiology at Mount Sinai Medical Center in New York. “The placement of drug-eluting stents in the infrapopliteal leg arteries is safe and effective and can significantly impact their care. Our results rival bypass surgery and are better than balloon angioplasty alone."
Primary patency (length of time the blood vessels stayed open and moved blood flow efficiently) for the 53-patient study at 12 months was 81.8 percent, said Dr. Lookstein, who also is an associate professor of radiology and surgery at Mount Sinai School of Medicine. Freedom from major amputation at follow-up was 90.6 percent for the entire group and 100 percent for patients with Rutherford category 4 (ischemic pain at rest) and 5 (lower-extremity ischemia associated with minor tissue loss) disease. The Rutherford categories are a severity classification scale for PAD that can be used to evaluate clinical improvement. Patients were followed for an average of 17 months.
Surgical bypass remains the mainstream therapy for blocked infrapopliteal arteries, but there are a growing number of patients who are unable to undergo this treatment because of their medical problems, said Dr. Lookstein. Attempts to treat CLI in PAD patients with below-the-knee angioplasty are hindered by high rates of restenosis, the need for repeat treatments and the continued progression of atherosclerotic disease. Drug-eluting stents are a potential solution to the limitations of endovascular treatment.
Over a four-year period, Dr. Lookstein's group at Mount Sinai Medical Center in New York studied 53 patients (32 men, 21 women) ranging in age from 43 to 93 who underwent implantation of 94 drug-eluting stents (80 sirolimus, 12 everolimus, 2 paclitaxel) to treat a suboptimal angioplasty result in an infrapopliteal artery. All patients had symptoms of critical limb ischemia with Rutherford grade 4, 5 or 6 disease at presentation prior to treatment. Initial technical success rate was 100 percent with all treated lesions having less than 10 percent residual angiographic stenosis at completion of the procedure. The mean number of stents placed per patient was 1.62 (range, 1-5), with the stent diameter ranging from 2.5 to 4 millimeters.
Angiographic, clinical and noninvasive vascular examination results were collected prospectively at regular intervals. Primary endpoints, including technical success of the revascularization procedure, primary patency, freedom from major amputation and survival at follow-up, rival those of conventional bypass surgery.
"Our study reinforces the fact that when it comes to treating cardiovascular disease, there is a wide range of safe and effective treatments," said Dr. Lookstein.
Multicenter randomized trials are necessary to support such promising results of the value of infrapopliteal drug-eluting stents in critical limb ischemia treatments, he added. In the United States, drug-eluting stents are FDA-approved for the coronary arteries but not for infrapopliteal arteries.
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"Single Center Experience With Drug-eluting Stents for Infrapopliteal Occlusive Disease in Patients With Critical Limb Ischemia," A.M. Fischman, S.S. Shah, E. Kim, P. Stangl, F. Nowakowski, J.L. Weintraub, R. Lookstein, all at Mount Sinai Medical Center, New York, N.Y., Society of Interventional Radiology 35th Annual Scientific Meeting March 13-18, 2010, Tampa, Fla.