One-year follow-up of the ASSENT-2 trial: a double-blind, randomized comparison of single-bolus tenecteplase and front-loaded alteplase in 16,949 patients with ST-elevation acute myocardial infarction.

BACKGROUND: Single-bolus tenecteplase and accelerated alteplase were shown to be equivalent for 30-day mortality rates in the double-blind Assessment of the Safety of a New Thrombolytic (ASSENT-2) study. The aim of this study is to assess mortality rates after 1-year follow-up.

METHODS AND RESULTS: One-year vital status was obtained from 92.8% of the patients initially enrolled in the ASSENT-2 trial. Completeness of follow-up was similar for both groups. At 1 year, mortality rates were 9.1% for alteplase and 9.2% for tenecteplase (risk ratio, 1.01; 95% CI, 0.91-1.12). The mortality rate between 30 and 365 days after enrollment was 2.6% for alteplase and 2.8% for tenecteplase (risk, 1.07; 95% CI, 0.88-1.30). A lower 30-day mortality rate in patients treated with tenecteplase after 4 hours of symptom-onset persisted at 1-year follow-up (10.9% vs 12.6% for alteplase), but was no longer statistically significant. There were also no significant differences in mortality rates between the 2 treatments in other major subgroups. In a Cox regression model, no significant interaction was observed between treatment assignment and age, sex, time-to-treatment, Killip class, body weight, and history of previous myocardial infarction, infarction location, systolic blood pressure, or heart rate.

CONCLUSIONS: One year after randomization, mortality rates remain similar in patients with acute myocardial infarction treated with an accelerated infusion of alteplase or a single bolus of tenecteplase.