Two hundred two units of Palmaz-Schatz coronary stents(PSS) were implanted to 194 patients, 156 male and 38 female, at 12 hospitals. Their clinical characteristics were ; 89 cases(46%) of unstable angina, 55 cases(28%) of stable angina, 46 cases(24%) of acute myocardial infarction(MI, Q:35 cases, non-Q:11 cases) and 4 cases of mixed angina with over 70% stenosis. The coronary angiographic findings were 121 single vessel(62%), 51 two vessel(26%) and 22 three vessel diseases(11%). Primary elective was indicated for 141 cases(70%), 112 for de nove and 29 for restenosis after PTCA. Stenting was performed as a bailout for 36 cases, 27 threatened closures and 9 acute closures. PSS were implanted in 25 cases with suboptimal result after PTCA. There were 8 acute closures. PSS were implanted in 25 cases with suboptimal result after PTCA. There were 8 cases for which 2 PSS were implanted, 4 for de novo and 4 for bailout. In 43 out of 46 acute MI cases, PSS were implanted inside infarct-related arteries. The coronary artery branches taken for this study were 102 left anterior descending coronary arteries(51%), 77 right coronary arteries(38%), 22 left circumflex arteries(11%) and 1 saphenous vein graft. PSS with diameter of larger than 3.5mm were implanted for 118 cases(58%). Success rates were 98% angiographically and 97% clinically. Complications during hospital stay were 2 Q-wave MIs, 1 emergency coronary bypass surgery, 1 acute closure, 1 sub-acute closure, 2 cardiac tamponade due to ruptured coroanry artery, 4 stent embolisms, 13 bleeding complications that required transfusion and 2 deaths.

Coronary artery angiographies were taken for 100 vessel sites of 98 patients traced, 77 male and 21 female, 6 months after stenting. Narrowing of inner diameter of 50% or more was defined as angiographic restenosis and 31 sites(31%) were subject to this catagory, 25% for PSS larger than 3.5mm and 39% for PSS smaller than 3.5mm(p<0.05). There were no differences in clinical characteristics of patient group that showed restenosis. However, the restenosis rate of Type A(classified before stenting) stenosis was noticeable low at 11.1% and the rate of restenois in left circumflex coronary artery was also low at 10%(p<0.05). The restenosis rates of elective and bailout stentings were 26% and 31% respectively. The rate of restenosis in de nove sites was 27%, which was significantly lower than that(46%) in restenosis sites(p<0.05).

PSS, when implanted to selected patients, can reduce the restenosis rate and is considered as a safe means for bailout.