Meta-Analysis Comparing Venoarterial Extracorporeal Membrane Oxygenation With or Without Impella in Patients With Cardiogenic Shock

Cardiogenic shock is associated with high short-term mortality. Venoarterial extracorporeal membrane oxygenation (VA-ECMO) is increasingly used as a mechanical circulatory support strategy for patients with refractory cardiogenic shock. A drawback of this hemodynamic support strategy is increased left ventricular (LV) afterload, which is mitigated by concomitant use of Impella (extracorporeal membrane oxygenation with Impella [ECPELLA]). However, data regarding the benefits of this approach are limited. We conducted a systematic search of Medline, EMBASE, and Cochrane databases to identify studies including patients with cardiogenic shock reporting clinical outcomes with Impella plus VA-ECMO compared with VA-ECMO alone. Primary outcome was short-term all-cause mortality (in-hospital or 30-day mortality). Secondary outcomes included major bleeding, hemolysis, continuous renal replacement therapy, weaning from mechanical circulatory support, limb ischemia, and transition to destination therapy with LV assist device (LVAD) or cardiac transplant. Of 2,790 citations, 7 observational studies were included. Of 1,054 patients with cardiogenic shock, 391 were supported with ECPELLA (37%). Compared with patients on only VA-ECMO support, patients with ECPELLA had a lower risk of short-term mortality (risk ratio [RR] 0.89 [0.80 to 0.99], I² = 0%, p = 0.04) and were significantly more likely to receive a heart transplant/LVAD (RR 2.03 [1.44 to 2.87], I² = 0%, p <0.01). However, patients with ECPELLA had a higher risk of hemolysis (RR 2.03 [1.60 to 2.57], I² = 0%, p <0.001), renal failure requiring continuous renal replacement therapy (RR 1.46 [1.23 to 174], I² = 11%, p <0.0001), and limb ischemia (RR 1.67 [1.15 to 2.43], I² = 0%, p = 0.01). In conclusion, among patients with cardiogenic shock requiring VA-ECMO support, concurrent LV unloading with Impella had a lower likelihood of short-term mortality and a higher likelihood of progression to durable LVAD or heart transplant. However, patients supported with ECPELLA had higher rates of hemolysis, limb ischemia, and renal failure requiring continuous renal replacement therapy. Future prospective randomized are needed to define the optimal treatment strategy in this high-risk cohort.