LONG-TERM ANGIOGRAPHIC AND CLINICAL OUTCOME AFTER IMPLANTATION OF A BALLOON-EXPANDABLE STENT IN THE NATIVE CORONARY CIRCULATION

Objectives. The purpose of this study was to examine the long term clinical and angiographic outcome after coronary stent implantation. Background. Previous reports have 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 angiographers utilizing an 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 clo sures, 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 +/- 0.39 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 greater than or equal to 50% diameter stenosis at followup, 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.