Optimal Strategy and Timing of Left Ventricular Venting During Veno-Arterial Extracorporeal Life Support for Adults in Cardiogenic Shock A Systematic Review and Meta-Analysis

Background: Veno-arterial extracorporeal life support (VA-ECLS) is widely used to treat refractory cardiogenic shock. However, increased left ventricular (LV) afterload in VA-ECLS can worsen pulmonary congestion and compromise myocardial recovery. Our objectives were to explore the efficacy, safety, and optimal timing of adjunctive LV venting strategies. Methods: A systematic search was performed on Medline, EMBASE, PubMed, CDSR, CCRCT, CINAHL, ClinicalTrials.Gov, and WHO ICTRP from inception until January 2019 for all relevant studies, including LV venting. Data were analyzed for mortality and weaning from VA-ECLS on the basis of timing of LV venting, along with adverse complications. Results: A total of 7995 patients were included from 62 observational studies, wherein 3458 patients had LV venting during VA-ECLS. LV venting significantly improved weaning from VA-ECLS (odds ratio, 0.62 [95% CI, 0.47-0.83]; P=0.001) and reduced short-term (30 day; risk ratio [RR], 0.86 [95% CI, 0.77-0.96]; P=0.008) but not in-hospital (RR, 0.92 [95% CI, 0.83-1.01] P=0.09) or long-term (6 months; RR, 0.96 [95% CI, 0.90-1.03]; P=0.27) mortality. Early (<12 hours; RR, 0.86 [95% CI, 0.75-0.99]; P=0.03) but not late (>= 12 hours; RR, 0.99 [95% CI, 0.71-1.38]; P=0.93) LV venting significantly reduced short-term mortality. Patients with LV venting spent more time on VA-ECLS (3.6 versus 2.8 days, P<0.001), and mechanical ventilation (7.1 versus 4.6 days, P=0.013). With the exception of hemolysis (RR, 2.18 [95% CI, 1.58-3.01]; P<0.00001), overall adverse events did not differ. Conclusions: LV venting, especially if done early (<12 hours), appears to be associated with an increased success of weaning and reduced short-term mortality. Future studies are required to delineate the importance of any or early LV venting adjuncts on mortality and morbidity outcomes.