Early invasive versus early conservative strategy in non-ST-elevation acute coronary syndrome: An outcome research study.

Abstract

An early invasive strategy (EIS) has been shown to yield a better clinical outcome than an early conservative strategy (ECS) in patients with non-ST-elevation acute coronary syndromes (NSTEACSs), particularly in those at higher risk according to the GRACE risk score. However, findings of the clinical trials have not been confirmed in registries. To investigate the outcome of patients with NSTEACS treated according to an EIS or a ECS in a real-world all-comers outcome research study. The primary hypothesis of the study was the non-inferiority of an ECS in comparison with an EIS as to a combined primary end-point of death, non-fatal myocardial infarction and hospital readmission for acute coronary syndromes at one year. Participating centres were divided into two groups: those with a pre-specified routine EIS and those with a pre-specified routine ECS. Two statistical analyses were performed: a) an 'intention to treat' analysis: all patients were considered to be treated according to the pre-specified routine strategy of that centre; b) a 'per protocol' analysis: patients were analysed according to the actual treatment applied. Cox model including propensity score correction was applied for all analyses. The intention to treat analysis showed an equivalence between EIS and ECS (11.4% vs. 11.1%) with regard to the primary end-point incidence at one year. In the three subgroups of patients according to the GRACE risk score (⩽ 108, 109-140, > 140), EIS and ECS confirmed their equivalence (5.3% vs. 3.9%, 8.4% vs. 7.6%, and 20.3% vs. 20.9%, respectively). When the per protocol analysis was applied, a reduction of the primary end-point at one year with EIS vs. ECS was demonstrated (6.2% vs. 15.3%, p=0.021); analysis of the subgroups according to the GRACE risk score numerically confirmed these data (3.1% vs. 6.5%, 5.1% vs. 10.0%, and 10.8% vs. 24.5%, respectively). In a real-life registry of all-comers NSTEACS patients, ECS was non-inferior to EIS; however, when EIS was applied according to clinical judgement, a reduction of clinical events at one year was demonstrated.