Impact of delayed presentation on management and outcome of non–ST-elevation acute coronary syndromes

BackgroundThe impact of delayed presentation on the management and outcomes of patients with non–ST-elevation acute coronary syndromes (NSTE-ACS) has not been well studied. Furthermore, the prognostic value of initial biomarker level in relation to the time of presentation has not been determined.MethodsThe Canadian ACS II registry was a national, multicenter, prospective observational study of 1,956 patients with NSTE-ACS (October 2002-December 2003). We compared the baseline characteristics, treatment, and outcomes in early (within 6 hours of symptom onset) versus late presenters (>6 hours). A logistic regression model was developed to examine the independent association of late presentation with 1-year mortality. We also evaluated the prognostic value of initial biomarker level in relation to early versus late presentation.ResultsA total of 1,219 (62.3%) patients presented early, whereas 727 (37.7%) presented late; their rates of in-hospital revascularization were similar (40.5% vs 42.5%, respectively, P = .39). There was also no significant difference in hospital mortality (1.6% vs 2.2%, P = .30) or 1-year mortality (7.6% vs 5.7%, P = .13) between early and late presenters. After adjusting for other prognosticators, late presentation was not an independent predictor of 1-year mortality (adjusted odds ratio 0.78, 95% confidence interval 0.48-1.26, P = .3). Elevated initial biomarker was independently associated with higher 1-year mortality (adjusted odds ratio 2.17, 95% CI 1.31-3.58, P = .002) regardless of whether hospital presentation was early or late (P for interaction = .74).ConclusionsThere is still considerable delay between symptom onset of NSTE-ACS and hospital presentation in the contemporary era. In contrast to studies of ST-elevation myocardial infarction, we found no significant differences in the management and outcome of early presenters as compared with late presenters with NSTE-ACS. Nevertheless, measures to reduce patient delay time should continue to be implemented. Initial biomarker status is a useful prognosticator irrespective of the delay time.