Therapeutic strategy for extracorporeal life support in patients with acute myocardial infarction complicating cardiopulmonary arrest

Purpose and methods: The therapeutic strategy for extracorporeal life support (ECLS), including the appropriate indication, management, limitation, and timing to switch from ECLS to a ventricular assist device (VAD), has not been fully characterized and remains a controversial issue in patients with AMI complicating cardiopulmonary arrest (CPA). To discuss these issues, the condition of patients before ECLS, subsequent treatment, biochemistry data during ECLS, and complications associated with ECLS were compared between patients who died and those discharged from the hospital. Results: Forty-seven patients with AMI without cardiac rupture or ventricular septum perforation [41 males, 6 females; aged 59.8±12.8 years; age range, 29-80 years] who did not recover from CPA despite extensive therapies, were treated with ECLS. Thirty-nine patients underwent PCI and 3 of these patients subsequently received CABG. Fourteen patients (29.8%) were discharged from the hospital. The outcome was not favorable for out-of-hospital CPA (O-CPA) patients, CPA of in-hospitalized patients and patients with low output syndrome (LOS). A favorable outcome was noted in patients with pulseless VT or Vf (LTA) after arrival at the hospital and those with one diseased vessel. Successful PCI for the responsible segment were essential for discharged patients. Complications associated with ECLS always developed in the patients who died, and the development of multiple organ failure was fatal. In biochemical examination during ECLS, levels of creatine kinase (CK), CK-MB, lactate dehydrogenase (LDH), serum creatinine (Cr), and amylase (AMY) in deceased patients were higher than those of discharged patients after starting ECLS, and increasing Cr and lactic acid (LA) were shown in deceased patients. The total operating time for ECLS was almost the same between the discharged and deceased patients groups, and the average time, about 4.6 days, is assumed to be a threshold level to decide to switch from ECLS to VAD. Conclusion: Patients with AMI who suddenly develop CPA with LTA without deteriorating LOS show the most appropriate indication for ECLS and those with one diseased vessel showed a high probability of recovering with ECLS. However, patients with LOS or O-CPA and CPA of in-hospitalized patients were associated with a poor outcome. In biochemical examination during ECLS, levels of CK, CK-MB, LDH, Cr, and AMY after starting ECLS were very informative to prepare for VAD, and increasing Cr and LA were considered signs to switch from ECLS to VAD. The decision to switch to VAD should be decided up until about 4.6 days from starting ECLS.