Background: Limited progress has been made in the management of cardiogenic shock (CS). Morbidity and mortality of refractory CS remain high. The effects of mechanical circulatory support (MCS) are promising, although many aspects are elusive. We evaluated efficacy and safety of early combined MCS (Impella microaxial pump + venoarterial extracorporeal membrane oxygenation [VA-ECMO]) in refractory CS and aimed to determine factors for decision-making in combined MCS.
Methods and results: We analyzed 69 consecutive patients with refractory CS from our registry requiring combined MCS. In 12 cases, therapy was actively withdrawn according to patient's will. Patients were severely sick (Survival After Venoarterial ECMO score mean±SD, -8.9±4.4) predicting 30% in-hospital survival; ventilation 94%, dialysis 56%. Impella pumps and VA-ECMO were combined early (duration of combined MCS: median 94 hours; interquartile range, 49-150 hours). Early MCS escalation stabilized patients rapidly, reducing number and doses of catecholamines (P<0.05 versus baseline) while hemodynamics improved. Reflecting an improved microcirculation, lactate levels normalized within 24 hours (P<0.05 versus baseline). Despite refractory CS and disease severity, survival was favorable (on MCS 61%, 30 days 49%, 6 months 40%). In multivariate Cox-regression, duration of shock-to-first device (hours, hazard ratio, 1.05 [95% CI, 1.01-1.08]; P=0.007) and lactate levels after 12 hours of MCS (hazard ratio, 1.28 [95% CI, 1.09-1.51]; P=0.002) independently predicted survival. Additional right ventricular failure predisposed to futility (hazard ratio, 8.48 [95% CI, 1.85-38.91]; P=0.006).
Conclusions: The early and consequent combination of MCS by Impella microaxial pumps and VA-ECMO enables stabilization and may rescue high-risk patients with refractory CS at low overall risk. Independent predictors of survival may guide prognostication, decision-making, and allocation of medical resources.
Keywords: catecholamine; decision-making; extracorporeal membrane oxygenation; hemodynamics; shock.