Early coronary angiography and survival after out-of-hospital cardiac arrest: a systematic review and meta-analysis

Background Although acute myocardial infarction is a common cause of out-of-hospital cardiac arrest (OHCA), the role of early coronary angiography in OHCA remains uncertain. We conducted a meta-analysis of observational studies to determine the association of early coronary angiography with survival in OHCA. Methods We searched multiple electronic databases for published studies on early coronary angiography in OHCA between 1 January 1990 and 18 January 2017. Studies were included if (1) restricted to only OHCA, (2) included an exposure group that underwent early coronary angiography within 1 day of arrest onset and a concurrent control group that did not undergo early coronary angiography, and (3) reported survival outcomes. We used a random-effects model to obtain pooled OR. I2 statistics and Cochran’s Q test were used to determine between-study heterogeneity. Results A total of 17 studies with 14 972 patients were included, of whom 6424 (44%) received early coronary angiography. Early coronary angiography was associated with higher odds of survival (pooled OR 2.54 (95% CI 1.94 to 3.33)) and survival with favourable neurological outcome (pooled OR 2.37 (95% CI 1.71 to 3.28)). However, there was substantial heterogeneity in our pooled estimate (I2=88% and p value for Cochran’s test <0.0001 for both outcomes). The large heterogeneity in pooled estimates was reduced after including adjusted estimates when available, and was explained by differences in methodological rigour and characteristics of included studies. Conclusion Among patients resuscitated from OHCA, early coronary angiography is associated with increased survival to discharge and favourable neurological outcome.