Left Ventricular Unloading During Extracorporeal Membrane Oxygenation in Patients With Cardiogenic Shock

Abstract

Background: Venoarterial extracorporeal membrane oxygenation (VA-ECMO) is a widely used form of mechanical circulatory support in patients with refractory cardiogenic shock. A common drawback of this modality is a resultant increase in left ventricular afterload. Objectives: The purpose of this meta-analysis was to examine the efficacy and safety of left ventricular unloading strategies during VA-ECMO in adult patients with cardiogenic shock. Methods: The authors performed a systematic search of studies examining left ventricular unloading during VA-ECMO in Medline, EMBASE, and the Cochrane library. The primary outcome was all-cause mortality. Secondary outcomes included limb ischemia, bleeding, need for renal replacement therapy, multiorgan failure, stroke or transient ischemic attack, and hemolysis. Results: Of 2,221 publications identified, 17 observational studies met the inclusion criteria. In total, outcomes in 3,997 patients were included with 1,696 (42%) receiving a concomitant left ventricular unloading strategy while on VA-ECMO (intra-aortic balloon pump 91.7%, percutaneous ventricular assist device 5.5%, pulmonary vein or transseptal left atrial cannulation 2.8%). There were 2,412 deaths (60%) in the total cohort. Mortality was lower in patients with (54%) versus without (65%) left ventricular unloading while on VA-ECMO (risk ratio: 0.79; 95% confidence interval: 0.72 to 0.87; p < 0.00001). Hemolysis was higher in patients who underwent VA-ECMO with left ventricular unloading. Otherwise, secondary outcomes were not demonstrably different in patients treated with VA-ECMO with versus without left ventricular unloading. Conclusions: In observational studies, left ventricular unloading was associated with decreased mortality in adult patients with cardiogenic shock treated with VA-ECMO. In the absence of prospective randomized data, left ventricular unloading may be considered for appropriately selected patients undergoing VA-ECMO support.