INTRACORONARY STENTING WITHOUT ANTICOAGULATION ACCOMPLISHED WITH INTRAVASCULAR ULTRASOUND GUIDANCE

Background The placement of stents in coronary arteries has been shown to reduce restenosis in comparison to balloon angioplasty. However, c linical use of intracoronary stents is impeded by the risk of subacute stent thrombosis and complications associated with the anticoagulant regimen. To reduce these complications, the hypothesis that systemic a nticoagulation is not necessary when adequate stent expansion is achie ved was prospectively evaluated on a consecutive series of patients wh o received intracoronary stents. Methods and Results From March 1993 t o January 1994, 359 patients underwent Palmaz-Schatz coronary stent in sertion. After an initial successful angiographic result with <20% ste nosis by visual estimation had been achieved, intravascular ultrasound imaging was performed. Further balloon dilatation of the stent was gu ided by observation of the intravascular ultrasound images. All patien ts with adequate stent expansion confirmed by ultrasound were treated only with antiplatelet therapy (either ticlopidine for 1 month with sh ort-term aspirin for 5 days or only aspirin) after the procedure. Clin ical success (procedure success without early postprocedural events) a t 2 months was achieved in 338 patients (94%). With an inflation press ure of 14.9+/-3.0 atm and a balloon-to-vessel ratio of 1.17+/-0.19, op timal stent expansion was achieved in 321 of the 334 patients (96%) wh o underwent intravascular ultrasound evaluation, with these patients r eceiving only antiplatelet therapy after the procedure. Despite the ab sence of anticoagulation, there were only two acute stent thromboses ( 0.6%) and one subacute stent thrombosis (0.3%) at 2-month clinical fol low-up. Follow-up angiography at 3 to 6 months documented two addition al occlusions (0.6%) at the stent site. At 6-month clinical follow-up, angiographically documented stent occlusion had occurred in 5 patient s (1.6%). At 6-month clinical follow-up, there was a 5.7% incidence of myocardial infarction, a 6.4% rate of coronary bypass surgery, and a 1.9% incidence of death. Emergency intervention (emergency angioplasty or bailout stent) for a stent thrombosis event was performed in 3 pat ients (0.8%). The overall event rate was relatively high because of in traprocedural complications that occurred in 16 patients (4.5%). Intra procedural complications, however, decreased to 1% when angiographical ly appropriately sized balloons were used for final stent dilations. T here was one ischemic vascular complication that occurred st the time of the procedure and one ischemic vascular complication that occurred at the time of angiographic follow-up. By 6 months, repeat angioplasty for symptomatic restenosis was performed in 47 patients (13.1%). Conc lusions The Palmaz-Schatz stent can be safely inserted in coronary art eries without subsequent anticoagulation provided that stent expansion is adequate and there are no other flow-limiting lesions present. The use of high-pressure final balloon dilatations and confirmation of ad equate stent expansion by intravascular ultrasound provide assurance t hat anticoagulation therapy can be safely omitted. This technique sign ificantly reduces hospital time and vascular complications and has a l ow stent thrombosis rate.