Primary angioplasty versus intravenous thrombolysis in patients with acutemyocardial infarction not included in randomized studies - Results from the MITRA trial

There have been some prospective randomized studies which compared primary angioplasty with intravenous thrombolysis in patients with an acute myocard ial infarction (AMI). However, a substantial number of patients with AMI wh o would not have been included in those trials are treated with one of thes e two therapeutic options. To describe the proportions, characteristics, an d outcome of these patients treated with primary angioplasty or thrombolysi s we analyzed the data of the prospective "Maximal Individual Optimized The rapy for Acute Myocardial Infarction" (MITRA) trial. Out of 3308 patients treated with primary angioplasty or thrombolysis, 737 (22.3 %) belonged to one of the following groups, not included in current r andomized trials: Left bundle branch block, non-diagnostic first EGG, pre-h ospital delay > 12 hours or unknown pre-hospital delay. Primary angioplasty was performed in 158/737 (21.4 %) and thrombolysis received 579/737 (78.6 %) of the patients. There were only minor differences regarding patients' characteristics and c oncomitant diseases between the two groups. Patients treated with primary a ngioplasty were 3 years younger (62 years median versus 65 years median (p < 0.036). They also more often showed overt heart failure at admission comp ared to patients treated with thrombolysis (primary angioplasty: 3.2 % vers us thrombolysis: 8.9 %, OR = 0.34, 95 % CI: 0.13-0.86). In-hospital time to intervention was 1 1/2 hours longer in patients treated with primary angio plasty (156 minutes median versus 47 minutes median, p = 0.001). beta-block ers were more often used with primary angioplasty compared to thrombolysis (70.31 % versus 55.9 %; OR = 1.87, 95 % CI: 1.28-2.72), as well as ACE inhi bitors (62 % versus 49.9 %; OR = 1.64, 95 % CI:1.14-2.35). Hospital mortali ty (8.2 % versus 16.4 %; OR = 0.46, 95 % CI: 0.25-0.84), as well as a combi ned endpoint of death, reinfarction, postinfarction angina, advanced heart failure, and stroke (24.1% versus 42.3 %, OR = 0.43, 95 % CI: 0.29-0.64) we re lower in patients treated with primary angioplasty compared to those tre ated with thrombolysis. Logistic regression analysis showed primary angiopl asty to be independently associated with a lower rate of the combined endpo int (OR = 0.73, 95 % CI: 0.59-0.91), after adjusting for confounding parame ters. All subgroups showed a more favorable outcome in patients treated wit h primary angioplasty. In clinical practice, patients with AMI, not included in current randomized trials comparing primary angioplasty with thrombolysis, account for 22 % o f all patients with AMI treated with one of those two therapies. Primary an gioplasty seems to be associated with a lower event rate compared to thromb olysis in these patients. This has to be confirmed by a prospective randomi zed trial.