The aim of this meta-analysis, which included all randomized studies carried out to date, was to compare an early invasive strategy vs. a delayed invasive strategy in patients undergoing non ST elevation myocardial infarction (NSTEMI).

Even though there is no doubt invasive strategies reduce events rate such as death and re-infarction in NSTEMI patients, the adequate time for intervention remains controversial. Waiting too long may cause events (mainly repeat angina and infarction) and rushing may be associated to periprocedural events, because plaques are too unstable, since antiaggregation and anticoagulants have had not acted yet.

A previous meta-analysis on early invasive strategy vs. delayed invasive strategy had included 7 randomized studies; since then there have been 3 new studies, and the present work aims at updating the information with 10 randomized studies and 6,397 patients.

Mean time between randomization and PCI was between 30 minutes and 14 hours in the early invasive strategy group vs. 18.3 to 86 hours in the delayed invasive strategy group.

There were no differences in mortality primary end point (4% early invasive vs. 4.7% delayed; CI 95%: 0.67 to 1.09; p=0.20). Acute myocardial infarction rate was also similar (6.7% vs. 7.7%; CI 95%: 0.53 to 1.45; p=0.62).

The early invasive strategy was associated to a reduction of recurrent ischemia and refractory angina (3.8% vs. 5.8%; CI 95%: 0.40 to 0.74; p<0.01) and also to a shorter hospital stay (mean 112 hours vs. 168 hours; p<0.01).

Mayor bleeding was similar between both groups (3.9% vs. 4.2%; p=0.64).

Conclusion

An early invasive strategy does not reduce the risk of death or acute myocardial infarction compared to a delayed strategy. A reduction of hospital stay and refractory angina was observed.

Editorial Comment

The RIDDLE-NSTEMI, published by J Am Coll Cardiol Intv. 2016, randomized 323 patients undergoing non ST elevation myocardial infarction to immediate intervention (<2 hrs. after randomization) vs. delayed intervention (2 to 72 hrs. after randomization) observing, at 30 days, primary end point of death and repeat MI was less frequent in the immediate intervention group (4.3% vs. 13%; p= 0.008).

This study was the first to provide evidence in favor of hard points such as death or infarction, but based only on 323 included patients, several randomized studies and 2 meta-analysis (including the present one) with contradicting results that seem insufficient to change the daily practice.

Original Title: Timing of Coronary Invasive Strategy in Non–ST-Segment Elevation Acute Coronary Syndromes and Clinical Outcomes And Updated Meta-Analysis.

Reference: Laurent Bonello et al. J Am Coll Cardiol Intv. 2016;9(22):2267-2276.

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