Objective: To investigate the safety of discharge of patients deemed at low risk of cardiac events after evaluation in a chest pain unit and to determine the prognostic effect of revascularization of patients deemed at high risk.
Patients and methods: The study population consisted of 1088 patients presenting at the emergency department from January 15, 2001, to September 1, 2006, with chest pain but without ischemia on electrocardiography or troponin elevation. Patients were managed by a chest pain unit protocol that included early exercise testing. Three groups of patients were distinguished: (1) those discharged after exercise testing (424 [39%]); (2) those in whom unstable angina was ruled out after in-hospital evaluation (208 [19%]); and (3) those in whom unstable angina was confirmed or not ruled out (456 [42%]). Of the 456 patients in group 3, 183 (40%) were revascularized at the index episode. The primary end point was the occurrence of myocardial infarction or death within 1 year. Adjustments were made for patient characteristics and a propensity score for revascularization (c statistic [0.83]).
Results: Groups 1 and 2 showed lower rates of the primary end point than group 3 (group 1: 7 [1.7%]; group 2: 1 [0.5%]; group 3: 62 [13.6%]; P=.001). In group 3, revascularization at the index episode did not reduce the primary end point in the univariate (22 [12%] vs 29 [11%]; P=.80) and multivariate (hazard ratio, 1.4; 95% confidence interval, 0.7-2.5; P=.40) analyses. In-hospital revascularization decreased the need for postdischarge revascularization (hazard ratio, 0.3; 95% confidence interval, 0.1-0.7; P=.01).
Conclusion: Chest pain unit protocols are associated with safe patient discharge. Although early revascularizations may decrease the need for postdischarge revascularizations, they may not improve 1-year outcomes by reducing the number of myocardial infarctions or deaths.