[Multicenter results of coronary implantation of balloon expandable Palmaz-Schatz vascular stents].

Intracoronary stenting was designed to handle acute vessel closure after balloon angioplasty and to reduce the rate of restenosis. In three cardiology centers the implantation of 200 balloon-expandable Palmaz-Schatz stents was attempted in 179 patients. The implantation was successful in 170 patients (95%). During bail-out implantation for acute vessel closure or symptomatic dissections after balloon angioplasty, implantation succeeded in 60 (91%) of 66 attempted patients, who recovered immediately from ischemia. Three patients received emergency bypass surgery and three patients were kept on medical therapy. Restenosis after 4 to 6 months, defined as > 50% diameter reduction, was documented angiographically in 18 (15.3%) of 118 presently controlled patients. Patients with single stent implantation (n = 106) presented a late restenosis rate of 10.4% in contrast to patients with multiple stent implantation (n = 12), who presented a restenosis rate of 58.4%. Similar results on restenosis were found for patients with elective and bail-out stent implantation. Acute thrombotic stent occlusion occurred in three patients (1.8%) during the first 24 h after stenting. Three to 9 days after implantation subacute stent thrombosis occurred in 15 (8.8%) of 170 patients. Despite adequate therapy including thrombolysis, balloon angioplasty or emergency bypass surgery in 14 of 15 patients Q-wave myocardial infarction was documented in six patients and non Q-wave myocardial infarction in five patients. The following parameters were identified as risk factors for the development of subacute stent thrombosis: bail-out indication, unstable angina, type C lesion, stenosis length > 1.5 cm, plaque area > 3.5 mm2, symptomatic dissection after balloon angioplasty, incomplete wrapping of the dissection after stenting and residual distal vessel irregularities after stenting. Bleeding complications occurred in 12.4% of the patients and were related to the anticoagulation and antiaggregation therapy. In conclusion, the implantation of Palmaz-Schatz stents is an excellent bail-out device to treat acute vessel closure or symptomatic dissections after angioplasty. Elective and bail-out single stent implantation is associated with a reduced rate of restenosis when compared to conventional balloon angioplasty. At present, subacute stent thrombosis and bleeding complications are the major limitations with a combined rate of 15.9%.