Impact of prehospital delay on mortality in patients with acute myocardialinfarction treated with primary angioplasty and intravenous thrombolysis

Background In patients with acute myocardial infarction treated with thromb olysis, longer times to treatment are associated with increasingly worse cl inical outcome. This relation may be different For treatment with primary a ngioplasty. Methods We analyzed the pooled data of the German acute myocardial infarcti on registries Maximal Individual Therapy in Acute Myocardial Infarction (MI TRA) and Myocardial Infarction Registry (MIR) to determine the influence of prehospital delays on hospital mortality rates. Primary angioplasty was pe rformed in 1063 patients and thrombolysis in 7552 patients. Results In patients treated with thrombolysis, in-hospital time to treatmen t was constantly 30 minutes median. In patients treated with primary angiop lasty, in-hospital time to treatment increased from 60 minutes median up to 87 minutes median with increasing prehospital delay. Hospital mortality ra tes slightly decreased with increasing prehospital delays in patients treat ed with primary angioplasty (P for trend =.02). However, in patients treate d with thrombolysis, mortality rate was nonsignificantly increased (P for t rend =.11). Logistic regression analysis showed no significant difference i n mortality rates between primary angioplasty and thrombolysis for prehospi tal delays of <3 hours. However, when prehospital delay was 23 hours, throm bolysis was independently associated with a higher mortality rate compared with primary angioplasty. Conclusions Compared with thrombolysis, primary angioplasty is independentl y associated with a lower mortality rate in prehospital delays of 23 hours. The reason for this may be a time-dependent loss of efficacy to achieve re perfusion for thrombolysis but not for primary angioplasty.