Extracorporeal membrane oxygenation for refractory cardiogenic shock after cardiac surgery: predictors of early mortality and outcome from 51 adult patients

Abstract

Extracorporeal membrane oxygenation (ECMO) offers temporary haemodynamic support for those with refractory cardiogenic shock after cardiac surgery. We review our 5-year experience regarding ECMO use on those who cannot be weaned from cardiopulmonary bypass after cardiac surgery. We analyse our cases, predict the prognostic factors of survival and compare the short-term and medium-term results. From January 2002 to December 2006, 1764 patients underwent cardiac surgery with cardiopulmonary bypass in our division. Among these, 51 patients (2.9%) required venoarterial-mode ECMO for haemodynamic support because of refractory postcardiotomy cardiogenic shock. The indication of ECMO was refractory cardiogenic shock despite adequate filling volumes, large-dose inotropes and intra-aortic balloon pump support. The following cardiac surgical procedures were performed: coronary artery bypass grafting (CABG), n=27; valvular surgery, n=11; CABG plus valvular surgery, n=7; heart transplantation, n=4 and other procedures, n=2. Average age was 63.0+/-15.7 years. There were 36 male and 15 female patients. Average duration of ECMO was 7.5+/-6.7 days. Twenty-seven (53%) patients could be successfully weaned from ECMO. The 30-day and 3-month mortalities were 49% (25/51) and 65% (33/51). The in-hospital mortality was 67% (34/51 patients). Seventeen (33%) patients could be successfully discharged. Fifteen (29%) patients were still alive at 1-year outpatient department (OPD) follow-up. ECMO provides a good temporary cardiopulmonary support in patients with postcardiotomy shock. The preoperative risk factors of failure to withdraw ECMO are poor left-ventricular ejection fraction, systolic blood pressure <90 mmHg and refractory severe metabolic acidosis. The peri-ECMO predictors of mortality include low serum albumin level, low platelet count, low oxygen pressure of the venous tube of the ECMO and poor cardiac systolic function.