Long-term angiographic and clinical outcome after implantation of a ballon-expandable stent in the native coronary circulation

Abstract

Objectives. The purpose of this study was to examine the long-term clinical and angiographic outcome after coronary implantation. Background. Previous reports haw shown a discordance between the excellent initial angiographic results and subsequent adverse clinical events after coronary artery stenting. Methods. Single Palmaz-Schatz stents were electively implanted in the native coronary arteries of 300 consecutive patients. Angiograms were obtained at baseline, after balloon angioplasty, after stent implantation and at 6 months after implantation. Films were analyzed by a panel of engiographers utilizing en automated edge detection program, Clinical events, including death, myocardial infarction, coronary bypass surgery and repeat angioplasty, were recorded for 1 year. Results. Although there were no acute in-laboratory vessel closures, stent thrombosis occurred in 14 patients (4.7%) at a mean ±SD of 5 ± 3 days after implantation. Two hundred fifty-eight (90%) of 286 eligible patients had follow-up angiography at 6.1 ± 2.2 months after stent implantation. Minimal lumen diameter increased from 0.80 ± 039 mm at baseline to 1.65 +- 0.51 mm after angioplasty and further increased to 2.55 ± 0.49 mm after stent placement (p = 0.0001). At follow-up there was a 0.85-mm late loss in lumen diameter, with a final minimal lumen diameter at 6 months of 1.70 ± 0.71 mm. Restenosis, defined as ≥ 50% diameter stenosis at follow-up, occurred in 14% of patients with previously untreated lesions and in 39% of patients with previous angioplasty (p < 0.001). Clinical events after 1 year for the entire group of 300 patients included death in 0.7%, myocardial infarction in 3.7%, bypass grafting in 8% and repeat angioplasty in 13%. Freedom from any adverse clinical event was 80% for all treated patients and 87% for those with previously untreated lesions. Conclusions. Elective use of this balloon-expandable stent in the native coronary circulation is associated with a low restenosis rate by quantitative angiography in previously untreated lesions and a favorable clinical outcome with an excellent event-free survival rate at 1 year. © 1994.