Three-Year Impact of Immediate Invasive Strategy in Patients With Non-ST-Segment Elevation Myocardial Infarction (from the RIDDLE-NSTEMI Study)

Previous studies compared clinical outcomes of early versus delayed invasive strategy in patients with non-ST-elevation acute coronary syndrome up to 1-year follow-up, but long-term data remain scarce. Our aim was to evaluate the long-term effects of immediate invasive intervention in patients with Non-ST-Segment Elevation Myocardial Infarction (NSTEMI). The Randomized Study of Immediate Versus Delayed Invasive Intervention in Patients With Non-ST-Segment Elevation Myocardial Infarction (RIDDLE-NSTEMI) was a randomized, investigator-initiated, parallel-group trial that assigned 323 patients with NSTEMI (1:1) to either immediate (median time to intervention 1.4 hours) or delayed invasive strategy (61.0 hours). The primary end point was the composite of death or new myocardial infarction (MI). At 3 years, immediate invasive intervention was associated with a lower rate of death or new MI, compared with a delayed invasive strategy (12.3% vs 22.5%, hazard ratio 0.50, 95% confidence interval 0.29 to 0.87, p = 0.014). The observed benefit of immediate intervention was mainly driven by an increased early reinfarction risk in delayed strategy, with similar new MI rates beyond 30 days (4.4% in the immediate and 5.6% in the delayed group, p = 0.61). Three-year mortality was 9.3% in the immediate invasive strategy, and 10.0% in the delayed strategy (p = 0.83). High baseline Global Registry of Acute Coronary Events score (>140) was associated with a significant increase in long-term mortality, regardless of the timing of invasive intervention. In conclusion, whereas immediate invasive intervention significantly reduced the early risk of new MI, the timing of invasive intervention appears to have no significant impact on clinical outcomes beyond 30 days, which seem to mostly be related to the baseline clinical risk profile.