Coronary angiography is essential for patients admitted with non-ST-elevation acute coronary syndrome, since it allows physicians to confirm the diagnosis, stratify the risk, and define the revascularization and antithrombotic management strategies.

There is no doubt that these patients should be studied invasively, but the timing for that is still uncertain.

Coronary catheterization within 72 hours from admission resulted in a reduction of mortality rates, ischemic recurrence, and hospital stay, compared with selective angiography as preferred strategy.

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A decrease in time up to a mere 24 hours was still associated with a reduction in the number of events, but only for high-risk patients (Global Registry of Acute Coronary Events [GRACE] score >140). Further attempts at reducing time may benefit this patient group.

This work assessed the outcomes for high-risk patients with non-ST-elevation ACS who were brought to the cath lab very early (<12 h), early (12-24 h), or late (>24 h).

These patients were included in the TAO (Treatment of Acute Coronary Syndrome with Otamixaban) Trial and randomized to receive heparin plus eptifibatide vs. otamixaban. Per protocol, they all were to be studied invasively within 72 hours.

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The primary endpoint was a composite of all-cause death and infarction within 180 days of randomization.

Coronary angiography was performed in 4071 patients. Among them, 1648 (40.5%) were admitted within 12 h, 1420 (34.9%) between the first 12 and 24 h, and 1003 were admitted after the first 24 h.

Compared to patients studied after the first 24 h, there was no benefit for those who underwent catheterization between the first 12 and 24 h, but there was benefit for patients studied very early (odds ratio [OR]: 0.71; 95% confidence interval [CI]: 0.55-0.91).

No difference was observed regarding bleeding complications.

Conclusion

Patients with non-ST-elevation ACS studied with coronary catheterization within 12 h from hospital admission experience a lower risk for death or infarction than those studied later (between the first 12 and 24 h, or after the first 24 h).

Editorial

While no difference was observed regarding bleeding complications with a very early invasive strategy, a reduction in these events (besides ischemic events) would be expected, since the use of anticoagulant agents is usually interrupted after revascularization. This work was unable to prove a reduction in bleeding complications, something that other studies (such as TIMACS, RIDDLE NSTEMI, and ACUITY) also failed to do. Differences in antiplatelet regimes, anticoagulant agents, and proportions of transradial access among the different studies may have influenced the outcomes.

Original title: Timing of Angiography and Outcomes in High-Risk Patients with Non-ST Segment Elevation Myocardial Infarction Managed Invasively: Insights from the TAO Trial.

Reference: Pierre Deharo et al. Circulation. 2017 Sep 11. Epub ahead of print.

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