Primary percutaneous transluminal coronary angioplasty for acute myocardial infarction in patients not included in randomized studies

Patients with acute myocardial infarction included in randomized trials com paring primary percutaneous transluminal coronary angioplasty (pPTCA) with thrombolysis represent a special subgroup of patients with a low event rate . Patients excluded from these trials represent a variety of different subg roups, with different patient characteristics and possibly different clinic al event rates. Primary PTCA was performed in 491 consecutive patients with acute myocardial infarction in the prospective multicenter observational M aximal Individual Therapy in Acute Myocardial Infarction trial. They were d ivided into the following groups: group I, patients fulfilling the inclusio n criteria of the randomized trials (284 of 491, 58%); group II, patients n ot included in these trials (207 of 491, 42%). Of group II the Following su bgroups were defined: group IIa, patients in cardiogenic shock (20 of 491, 4.1%); group IIb, patients with a left bundle branch block (12 of 491, 2,4% ); group IIc, patients with contraindications for thrombolysis (42 of 491, 8.6%); group IId, patients with a nondiagnostic first electrocardiogram (95 of 491, 19.3%); group Ile, patients with a prehospital delay of >12 hours (72 of 491, 14.7%); group IIf, patients with an unknown prehospital delay ( 30 of 491, 6.1%). A comparison of groups I and II showed similar baseline c haracteristics but a higher clinical event rate during hospitalization was seen in group II: combined end point of death, reinfarction, heart failure equal to or greater than NYHA class III, any stroke or postinfarction angin a, 26.6% versus 18%; p 0.022. Hospital deaths were nearly twice as high in these patients, without reaching statistical significance (10.6% vs 6%; p = 0.06). The subgroups of group II showed quite different rates of clinical events. In-hospital death rates were: IIa, 40% (8 of 20); IIb, 8% (1 of 12) ; IIc, 12% (5 of 42); IId, 5% (5 of 95); Ile, 6% (4 of 72); and IIf, 13% (4 of 30), The incidence of the combined end point was 60% (1 2 of 20) in IIa , 33% (4 of 12) in IIb, 29% (12 of 42) in Pie, 16% (15 of 95) in IId, 26% ( 19 of 72) in Ile, and 33% (10 of 30) in IIf. Thus, in clinical practice, ab out half of the patients treated with pPTCA would not have been included in randomized trials comparing pPTCA with thrombolysis. These patients repres ent a population at higher risk for in hospital clinical events. However, t hey do represent very different nonhomogenous subgroups with different clin ical event rates. (C) 1999 by Excerpta Medica, Inc.