Extracorporeal cardiopulmonary resuscitation for out-of-hospital cardiac arrest: A systematic review and meta-analysis of randomized and propensity score-matched studies.

BACKGROUND: In selected patients with refractory out-of-hospital cardiac arrest, extracorporeal cardiopulmonary resuscitation represents a promising approach when conventional cardiopulmonary resuscitation fails to achieve return of spontaneous circulation. This systematic review and meta-analysis aimed to compare extracorporeal cardiopulmonary resuscitation to conventional cardiopulmonary resuscitation. METHODS: We searched PubMed, EMBASE, and the Cochrane Central Register of Controlled Trials up to November 28, 2021, for randomized trials and observational studies reporting propensity score-matched data and comparing adults with out-of-hospital cardiac arrest treated with extracorporeal cardiopulmonary resuscitation with those treated with conventional cardiopulmonary resuscitation. The primary outcome was survival with favorable neurological outcome at the longest follow-up available. Secondary outcomes were survival at the longest follow-up available and survival at hospital discharge/30 days. RESULTS: We included six studies, two randomized and four propensity score-matched studies. Patients treated with extracorporeal cardiopulmonary resuscitation had higher rates of survival with favorable neurological outcome (81/584 [14%] vs. 46/593 [7.8%]; OR = 2.11; 95% CI, 1.41-3.15; p < 0.001, number needed to treat 16) and of survival (131/584 [22%] vs. 102/593 [17%]; OR = 1.40; 95% CI, 1.05-1.87; p = 0.02) at the longest follow-up available compared with conventional cardiopulmonary resuscitation. Survival at hospital discharge/30 days was similar between the two groups (142/584 [24%] vs. 122/593 [21%]; OR = 1.26; 95% CI, 0.95-1.66; p = 0.10). CONCLUSIONS: Evidence from randomized trials and propensity score-matched studies suggests increased survival and favorable neurological outcome in patients with refractory out-of-hospital cardiac arrest treated with extracorporeal cardiopulmonary resuscitation. Large, multicentre randomized studies are still ongoing to confirm these findings.