Blood lactate predicts survival after percutaneous implantation of extracorporeal life support for refractory cardiac arrest or cardiogenic shock complicating acute coronary syndrome: insights from the CareGem registry

Refractory cardiogenic shock (RCS) or refractory cardiac arrest (RCA) complicating acute coronary syndrome (ACS) is associated with extremely high mortality rate. Veno-arterial extracorporeal life support (VA-ECLS) represents a valuable therapeutic option to stabilize patients’ condition before or at the time of emergency revascularization. We analyzed 29 consecutive patients with RCS or RCA complicating ACS, and implanted with VA-ECLS in two centers who have adopted a similar, structured approach to ECLS implantation. Data were collected from January 2010 to December 2015 and ECLS had to be percutaneously implanted either before (within 48 h) or at the time of attempted percutaneous coronary revascularization (PCI). We investigated in-hospital outcome and factors associated with survival. Twenty-one (72%) were implanted for RCA, whereas 8 (28%) were implanted on ECLS for RCS. All RCA were witnessed and no-flow time was shorter than 5 min in all cases but one. All patients underwent attempted emergency PCI, using radial access in ten cases (34.5%), whereas in three patients a subsequent CABG was performed. Overall, ten patients (34.5%) survived, nine of them with a good neurological outcome. Life threatening complications, including stroke (4 pts), leg ischemia (4 pts), intestinal ischemia (5 pts), and deep vein thrombosis 2 pts), occurred frequently, but were not associated with in-hospital death. Main cause of death was multi-organ failure. PCI variables did not predict survival. Survivors were younger, with shorter low-flow time, and with ECLS mainly implanted for RCS. At multivariate analysis, levels of lactate at ECLS implantation (OR 4.32, 95%CI 1.01–18.51, p = 0.049) emerged as the only variable that independently predicted survival. In patients with RCA or RCS complicating ACS who are percutaneously implanted with ECLS before or at the time of coronary revascularization, in hospital survival rate is higher than 30%. Level of lactate at ECLS implantation appears to be the most important factor to predict survival.