Acute coronary angiography in patients resuscitated from out-of-hospital cardiac arrest-A systematic review and meta-analysis

INTRODUCTION: Out-of-hospital cardiac arrest has a poor prognosis. The main aetiology is ischaemic heart disease. AIM: To make a systematic review addressing the question: "In patients with return of spontaneous circulation following out-of-hospital cardiac arrest, does acute coronary angiography with coronary intervention improve survival compared to conventional treatment?" METHODS: Peer reviewed articles written in English with relevant prognostic data were included. Comparison studies on patients with and without acute coronary angiography were pooled in a meta-analysis. RESULTS: Thirty-two non-randomised studies were included of which 22 were case-series without patients with conservative treatment. Seven studies with specific efforts to control confounding had statistical evidence to support the use of acute coronary angiography following resuscitation from out-of-hospital cardiac arrest. The remaining 25 studies were considered neutral. Following acute coronary angiography, the survival to hospital discharge, 30 days or six months ranged from 23% to 86%. In patients without an obvious non-cardiac aetiology, the prevalence of significant coronary artery disease ranged from 59% to 71%. Electrocardiographic findings were unreliable for identifying angiographic findings of acute coronary syndrome. Ten comparison studies demonstrated a pooled unadjusted odds ratio for survival of 2.78 (1.89; 4.10) favouring acute coronary angiography. CONCLUSION: No randomised studies exist on acute coronary angiography following out-of-hospital cardiac arrest. An increasing number of observational studies support feasibility and a possible survival benefit of an early invasive approach. In patients without an obvious non-cardiac aetiology, acute coronary angiography should be strongly considered irrespective of electrocardiographic findings due to a high prevalence of coronary artery disease.