OBSERVED VERSUS PREDICTED MORTALITY IN PATIENTS WITH ACUTE CORONARY SYNDROMES AND LOW-RISK GRACE SCORES

Abstract

Guidelines recommend that patients with low-risk acute coronary syndromes (ACS) can be monitored in chest pain units or in hospital telemetry wards; however, up to two-thirds of patients with ACS are admitted to coronary care units (CCU). The outcomes of patients with low-risk ACS admitted to CCUs have not been well described. We examined the observed versus predicted mortality rates in patients with low-risk ACS admitted to CCUs. We created a linked administrative database using a population-based cohort of hospitalized patients (n = 6232) with an ACS admitted to a CCU in the province of Alberta between November 1, 2014 and June 30, 2016. We examined the observed versus GRACE score predicted mortality rates amongst 1290 patients with low-risk ACS defined as a GRACE score ≤ 110. The secondary outcome was critical care restricted therapies. The predicted number of in-hospital deaths was 7 (0.5%), but no in-hospital deaths were observed. In the entire cohort, no in-hospital deaths were observed among patients with a GRACE score < 119 (Figure). Of the 1290 low-risk patients, 579 (45%) required critical care restricted intravenous therapies; but, this was almost exclusively intravenous nitroglycerin (578 patients). Only one patient required dopamine. A total of 10 (0.8%) required non-invasive mechanical ventilation; none required invasive mechanical ventilation. In a large cohort of patients with low-risk GRACE scores admitted to a CCU, no in-hospital mortality was observed. In addition, there was no need for need for advanced critical care therapies beyond intravenous nitroglycerin. These findings support the routine admission of low-risk ACS patients to low-intensity hospital telemetry wards when critical care restricted therapies are not required. Future initiatives designed to decrease unnecessary low-risk CCU admissions have the potential to reduce critical care capacity strain and hospital costs.