Background: In intermediate- and high-risk non-ST elevated acute coronary syndrome (NSTE-ACS) patients, a routine invasive approach is recommended. The timing of coronary angiography remains controversial. To assess whether an immediate (<3 hours) invasive treatment strategy would reduce infarct size and is safe, compared with an early strategy (12-24 hours), for patients admitted with NSTE-ACS while preferably treated with ticagrelor.
Methods: In this single-center, prospective, randomized trial an immediate or early invasive strategy was randomly assigned to patients with NSTE-ACS. At admission, the patients were preferably treated with a combination of aspirin, ticagrelor and fondaparinux. The primary endpoint was the infarct size as measured by area under the curve (AUC) of CK-MB in 48 hours. Secondary endpoints were bleeding outcomes and major adverse cardiac events (MACE): composite of all-cause death, MI and unplanned revascularization. Interim analysis showed futility regarding the primary endpoint and trial inclusion was terminated.
Results: In total 249 patients (71% of planned) were included. The primary endpoint of in-hospital infarct size was a median AUC of CK-MB 186.2 ng/mL in the immediate group (IQR 112-618) and 201.3 ng/mL in the early group (IQR 119-479). Clinical follow-up was 1-year. The MACE-rate was 10% in the immediate and 10% in the early group (hazard ratio [HR] 1.13, 95% CI: 0.52-2.49).
Conclusions: In NSTE-ACS patients randomized to either an immediate or an early-invasive strategy the observed median difference in the primary endpoint was about half the magnitude of the expected difference. The trial was terminated early for futility after 71% of the projected enrollment had been randomized into the trial.
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