Clinical Profile of Restenosis

Abstract

The actual number of arterial interventions of one type or another performed each year in the United States is estimated to be between 550,000 and 600,000. This includes bypass grafts, endarterectomies, and a variety of intraluminal procedures which blast, burn or break the plaque. They are about equally divided between the coronary and the rest of the circulation but unequally distributed as to procedure. In the carotid artery surgical endarterectomy is the overwhelming favorite with balloon angioplasty under cautious trial in a handful of centers. In the coronary circulation angioplasty may enjoy a slight edge for the present, but more repeat procedures are being referred for bypass surgery. The renal artery is preferentially treated by angioplasty and, over the years, has yielded the best results for this procedure in any arterial territory. Bypass grafts dominate methods to improve lower extremity circulation and are often combined with balloon angioplasty to relieve a proximal stenosis. The early results with all these techniques are generally excellent. Morbidity and mortality are low, and functional performance is satisfactory in most cases. Over the long term, as short as a few months and as long as ten years, results are disappointing due to recurrence of symptoms and the need for reintervention. In round numbers this amounts to approximately 50% of patients. Secondary procedures as compared to primary are approaching 50% of the case load in many clinics. At least 50% of all recurrences, and much more than this number of early recurrences, are due to an exuberant overgrowth of the myointimal cell and an excessive accumulation of extracellular matrix at the site of the angioplasty or the graft anastomosis. There are two noteworthy exceptions to these generalizations: the internal mammary artery as an aorta-coronary conduit and the synthetic graft in the aorta-iliac position.