Use and Timing of Coronary Angiography and Associated In-hospital Outcomes in Canadian Non-ST-Segment Elevation Myocardial Infarction Patients: Insights from the Canadian Global Registry of Acute Coronary Events

Background: Although an early invasive approach has become standard strategy for the management of non-ST-segment elevation myocardial infarction (NSTEMI), the frequency and timing in Canada is uncertain. Methods: We examined the use and timing of coronary angiography, revascularization, and cardiovascular outcomes of NSTEMI patients: (1) admitted on weekdays vs weekends; and (2) stratified according to presentation risk level, in the Canadian Global Registry of Acute Coronary Events (GRACE)/Expanded GRACE (GRACE(2))/Canadian Registry of Acute Coronary Events (CANRACE) population. Results: Of 6711 NSTEMI patients, 1956 (29.1%) were admitted on the weekend. The median (interquartile range) wait time for coronary angiography was 58 (32-106) and 70 (50-112) hours for weekday and weekend patients, respectively (P 0.32). Compared with lowerintermediate risk, higher-risk patients were less likely to undergo angiography (44.7% vs 69.7% for weekdays and 45.2% vs 69.6% for weekends; both P < 0.0001) and waited longer for angiography (median 71 vs 61 hours; P < 0.0001). Weekend admission was independently associated with higher mortality (adjusted odds ratio [OR], 1.52; 95% confidence interval [CI], 1.15-2.01; P = 0.004), recurrent ischemia (adjusted OR, 1.16; 95% CI, 1.01-1.32; P = 0.03), and heart failure (adjusted OR, 1.28; 95% CI, 1.00-1.63; P = 0.048) but not with reinfarction. Conclusions: Median wait time for angiography in Canadian NSTEMI patients admitted on the weekend was not significantly longer than for those who presented on a weekday. Patients admitted on weekends had higher adjusted mortality and cardiovascular event rates. Higher-risk patients were less likely to undergo angiography and waited longer, with higher observed in-hospital event rates. Systematic, guideline-recommended risk stratification should be considered to ensure that optimal management strategies (eg, timely coronary angiography in higher-risk patients) are matched to level of risk.