Whether coronary angiography was performed more or less than 24 hours after non-ST-elevation acute coronary syndrome did not affect patient mortality, according to a meta-analysis.
Researchers compiled data from eight trials with 5,324 patients and a median follow-up of 180 days to compare early versus delayed invasive strategies in patients presenting with non-ST-elevation acute coronary syndrome. They found an insignificant reduction in mortality in the early invasive group compared to the late one (hazard ratio [HR], 0.81; 95% CI, 0.64 to 1.03). Results were published online Aug. 1 by The Lancet.
Certain subgroups of high-risk patients did appear to have lower mortality with an early invasive strategy, including those with elevated cardiac biomarkers at baseline (HR, 0.761; 95% CI, 0.581 to 0.996), diabetes (HR, 0.67; 95% CI, 0.45 to 0.99), a GRACE (Global Registry of Acute Coronary Events) risk score more than 140 (HR, 0.70; 95% CI, 0.52 to 0.95), or age 75 years or older (HR, 0.65; 95% CI, 0.46 to 0.93). The study authors concluded that the early invasive strategy did not reduce mortality overall but that it might be beneficial for certain high-risk patients.
The authors noted that guidelines currently recommend immediate angiography for all unstable very high-risk patients and angiography within 24 hours for patients with positive biomarkers, dynamic ST-T changes, or a GRACE score more than 140. This study's results might suggest adding older patients and patients with diabetes to that group, but the authors cautioned that tests for interaction were negative in all of their subgroup analyses, so these findings should be considered exploratory and hypothesis-generating.
The study was limited by a number of factors, including relying heavily on the TIMACS (Timing of Intervention in Acute Coronary Syndromes) trial (which contributed 56.9% of patients) and variation in timing of angiography. The median time to angiography with the early invasive strategy was less than three hours in most of the included trials but 14 hours in TIMACS, the authors reported. Most of the data were also gathered before high-sensitivity troponin assays became standard.
An accompanying comment noted that adding older patients and those with diabetes to the group recommended for early treatment has “enormous logistic implications.” The commenters also observed that “the lack of a difference in mortality between invasive strategies suggests that most patients with acute coronary syndrome can be treated safely with either early intervention or delayed intervention.”