Thirty-two non-randomised studies (4,781 patients) were included in the review. Twenty-two studies were case-series without a comparison group. Ten comparative studies (3,103 patients) were pooled in a meta-analysis; sample size ranged from 72 to 986.
Seven studies were classified as supporting acute coronary angiography, following the return of spontaneous circulation, after out-of-hospital cardiac arrest. Twenty-five studies were neutral.
Fifteen studies (792 patients) reported on acute coronary angiography in patients with ST-segment elevation myocardial infarction. Survival ranged from 41% to 92%.
Five studies (821 patients) on systematic acute coronary angiography in patients without an obvious non-cardiac aetiology reported survival ranging from 31% to 81%.
Two studies (15 and 50 patients) with selective inclusion criteria had survival of 73% and 82%.
The 10 comparative studies reported on patients resuscitated from cardiac arrest of mixed aetiology, with acute coronary angiography only performed for some patients (from 14% to 83%). Those patients undergoing acute coronary angiography had better survival. All studies except the smallest and oldest one had a statistically significant unadjusted odds ratio that favoured acute coronary angiography. The pooled unadjusted odds ratio was 2.78 (95% CI 1.89 to 4.10). There was statistically significant heterogeneity (Ι²=74%).