Successfully Resuscitated Cardiac Arrest is Associated with Reduced In-hospital, but not Long-term Survival in Acute Coronary Syndrome

Introduction: Acute coronary syndrome (ACS) complicated by pre-hospital cardiac arrest (CA) is commonly associated with poor clinical outcomes. Data regarding longer term prognosis and the effects of contemporary therapies are lacking in this cohort. We sought to assess the impact of successfully resuscitated cardiac arrest on ACS outcomes in routine clinical practice. Methods: The Australian Collaborative Acute Coronary Syndromes Prospective Audit (ACACIA, n = 3402, PM_L_0051) is a prospective multi-centre registry of ST-segment elevation myocardial infarction and intermediate to high-risk non-ST-segment elevation ACS patients, involving 39 Australian metropolitan and rural sites. ACS patients presenting following successfully resuscitated cardiac arrest were the focus of this investigation. Patient characteristics, management and clinical outcomes were assessed. Results: In the seventy-nine patients assessed, successfully resuscitated, pre-hospital CA strongly predicted in-hospital mortality (HR 17.2, 95% CI 8.9–33.1, p < 0.0001). Admission glomerular filtration rate (eGFR) <60 mL/min was strongly associated with increased in-hospital mortality following CA (HR 4.7, 2.5–8.8, p < 0.0001). An invasive management strategy was associated with a marked reduction in in-hospital mortality (HR 0.42, 0.23–0.79, p = 0.007) despite multivariate adjustment and exclusion of patients dying within 24-h of hospital presentation. Notwithstanding a poor short-term prognosis, no incremental hazard was seen at 12-month follow-up in ACS patients surviving to hospital discharge following CA (HR 1.2, 0.29–4.9, p = 0.79). Conclusions: Resuscitated CA prior to hospitalisation strongly predicted in-hospital mortality, but not post-discharge survival. The substantial in-hospital survival advantage conferred by early invasive therapy lends further support to the routine invasive management of high-risk ACS patients.