Early angiography is not associated with a reduction in mortality compared with a more delayed invasive strategy in patients with non-ST-elevation acute coronary syndrome (NSTE-ACS). However, a new meta-analysis published by The Lancet supports the idea that certain high-risk patients would benefit from it.

Patients with elevated cardiac biomarkers, a high GRACE score, diabetes, or advanced age might obtain a decrease in their mortality rate with early angiography, as opposed to a delayed strategy.

This benefit as regards mortality had not been proved, thus perpetuating over time the debate on the optimal moment to bring patients with NSTE-ACS to the cath lab. Furthermore, both American and European guidelines timidly recommend studying patients with elevated troponin levels or a GRACE score >140 within the first 24 hours.

Read also: “Follow-up at 10 years for invasive vs. conservative strategy for non-ST-segment elevation infarction”.

It should be acknowledged that the outcome of this meta-analysis as regards the global population was neutral. In consequence, this benefit as regards mortality for these specific risk sub-groups should be considered as a hypothesis to be tested in future studies.

The meta-analysis recently published in The Lancet included 8 studies with over 5300 patients. The range of angiography timing was wide among works, from the ABOARD study, in which patients were brought to the cath lab immediately, to the TIMACS study, in which early strategy was defined as that implemented within 24 hours.

Similarly, the range of delayed invasive strategy timing was also wide, from the ABOARD study, in which all patients were studied at the following work day, to studies that allowed for up to 72 hours from the onset of symptoms. The mean follow-up, considering all studies, was 180 days.

Read also: “CTO in patients with acute myocardial infarction increases long term mortality”.

Globally, there was no significant reduction in mortality among patients randomized to an early invasive strategy vs. a delayed invasive strategy (hazard ratio [HR]: 0.81; 95% confidence interval [CI]: 0.64-1.03).

However, in the pre-specified analysis of high-risk patients, there was lower mortality in patients with elevated troponin (HR: 0.76; 95% CI: 0.58-1.00), diabetes (HR: 0.67; 95% CI: 0.45-0.99), a GRACE score >140 (HR: 0.70; 95% CI: 0.52-0.95), and aged 75 years or older (HR: 0.65; 95% CI: 0.46-0.93).

European guidelines recommend invasive angiography within 24 hours for high-risk patients with NSTE-ACS, and within 72 hours for intermediate-risk patients. Immediate invasive strategy is recommended only for extremely-high-risk patients, such as those with refractory angina or hemodynamic instability. ACC/AHA guidelines recommend similar management options, and that is as far as evidence goes. This meta-analysis presents too many limitations to become the foundations for a guideline update.

The eight studies included randomized patients from 2000 to 2016, which represents a long time interval. Anti-platelet drugs have evolved, stents have evolved, biomarker analysis has evolved, and there will be no definitive conclusion without a new study comparing early invasive strategy vs. delayed invasive strategy in patients with non-ST-elevation acute coronary syndrome.

Original title: Optimal Timing of an Invasive Strategy in Patients with Non-ST-Elevation Acute Coronary Syndrome: A Meta-Analysis of Randomised Trials.

Reference: Jobs A et al. Lancet. 2017; Epub ahead of print.

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