Abstract

Objectives: To study the clinical significance of infarct location during long term follow up in a trial comparing thrombolysis with primary angioplasty.

Design: Retrospective longitudinal cohort analysis of prospectively entered data.

Setting: Patients with acute ST elevation myocardial infarction (STEMI) treated with primary percutaneous coronary intervention (PCI).

Patients: In the Zwolle trial 395 patients with acute STEMI were randomly assigned to intravenous streptokinase or PCI.

Main outcome measures: Survival according to infarct location and treatment after 8 (2) years of follow up.

Results: 105 patients died: 63 patients in the streptokinase group and 42 patients in the primary PCI group (relative risk (RR) 1.6, 95% confidence interval (CI) 1.0 to 2.6; p  =  0.03). In patients with non-anterior STEMI there was no difference in mortality between streptokinase and PCI treated patients (RR 1.1, 95% CI 0.6 to 2.1; p  =  0.68) but the streptokinase group had significantly more major adverse cardiac events (MACE) than the PCI group (RR 2.1, 95% CI 1.2 to 3.6). The number needed to treat to prevent one MACE was four. In patients with anterior STEMI, mortality was higher in the streptokinase group than in the PCI group (RR 2.7, 95% CI 1.4 to 5.5; p  =  0.004). The number needed to treat to prevent one death was five. Kaplan-Meier analysis confirmed the benefits of primary angioplasty in the first year and showed additional benefit of PCI compared with streptokinase between 1–8 years after the acute event.

Conclusions: Patients with anterior STEMI have better long term survival when treated with PCI than with streptokinase. In patients alive one year after the acute event, PCI confers a significant additional survival benefit, probably due to better preserved residual left ventricular function.