Abstract P17: Risk Analysis of Patients With Acute Myocardial Infarction Complicated by Deep Cardiogenic Shock Receiving Emergency Coronary Artery Bypass Grafting and Perioperative ECMO Support
Background: Cardiogenic shock (CS) is the most common cause of death in patients hospitalized with acute myocardial infarction (AMI). In profound CS coronary revascularization and temporary circulatory support are mandatory to allow recovery in these otherwise doomed patients. Aim of the study was to evaluate risk factors for hospital mortality of patients suffering from AMI+CS undergoing coronary artery bypass graft surgery (CABG) and ECMO support.
Methods: Between 01/2000 and 12/2007 45/302 (14.9%) surgical AMI+CS patients required perioperative ECMO support for acute heart failure. We evaluated 44 pre-, 18 intra- and 28 postoperative risk factors for mortality by logistic regression models. Cumulative survival was estimated by Kaplan-Meier analysis.
Results: Age was 65.3y, 86.7% were male, ejection fraction was 32.3±14.9%, logEuroScore was 43.1±17.9%, 53.3% STEMI. Preoperative ventilation was required in 57.7%, inotropic support was necessary in 82.2% and 48.8% received preoperative IABP support. Mean distal anastomosis were 2.71±0.90/pts. ECMO was established by thoracic (62.2%) or extrathoracic (37.7%) cannulation. ECMO support was 99.2±72.8 hours. IABP implantation was inserted in 91.1%. Mean drainage loss was 4.0 liter/48h. Weaning from ECMO was successful in 25 pts (55.6%), six patients were bridged to left ventricular assist device (13.3%) and 14 pts (31.1%) died on ECMO. Mean postoperative stay was 21.6 days. Overall hospital mortality was 73.3% (33 pts.). Significant univariate risk factors for hospital mortality were peripheral vascular disease (p=0.018) and pre-existing renal insufficiency (p=0.007). All patients presenting these risk factors died. Postoperative CK-MB levels on POD 1 (364.3U/l vs.164.3U/l, p=0.018) and POD 2 (199.1U/l vs. 64.6U/l, p=0.024) were significantly higher in hospital dead. Cumulative survival was 35.6% after 30 days and 16.7% after 1 and 5 years, respectively.
Conclusion: ECMO support is an acceptable option for patients with refractory CS in AMI after CABG that otherwise would die allowing a fourth of all patients to survive. ECMO is justified by good long-term survival of hospital survivors. Because of high morbidity and mortality, ECMO indication has to be made on an individual risk profile.