Autopsy findings in patients on postcardiotomy extracorporeal membrane oxygenation (ECMO)

Abstract

Objectives: To assess the clinical sensitivity of causes of death, concomitant diseases and postoperative complications including thromboembolic events in ECMO patients.

Methods: Between January 2000 and December 2004 154/202 patients (76.2%) died after postcardiotomy ECMO circulatory support. Autopsy was performed in 78 (50.6%) consecutive patients. Clinical and post-mortem data were prospectively recorded and compared concerning causes of death and postoperative complications including venous and arterial thromboembolisms and significant comorbidities.

Results: Mean age was 62.1+/-11.3 years, ejection fraction was 43.4+/-17.3%. 39.7% were emergency operations including acute coronary syndrome in 25.6% and preoperative cardiogenic shock in 28.2%. Successful ECMO weaning rate was 43.6%. Mean postoperative survival was 11.3 days. Premortem unknown concomitant diseases were found in 63 patients (80.8%) with clinical relevance in 9 patients (11.5%). Clinically unrecognized postoperative complications were found in 59 patients (75.6%) including acute cerebral infarction (n=7), acute bowel ischemia (1), intestinal perforation (3), pneumonia (4), venous thrombus formation (25) and systemic thromboembolic events (24). Clinically based causes of death were cardiac in 62.8%, multi-organ failure in 10.3%, cerebral in 5.1%, respiratory in 10.3%, fatal pulmonary embolism in 2.6%, technical in 5.1%, and others in 3.8%. Unexpected causes of death were found by autopsy in 22 patients (28.2%) including myocardial infarction (n=5), acute heart failure (4), fatal pulmonary embolism (2), pneumonia (2), ARDS (1), lung bleeding (1), fatal cerebrovascular event (4) and multiorgan failure (3).

Conclusions: In ECMO patients major discrepancies between clinical and post-mortem examination were found. The true incidence of thromboembolic events is highly underestimated by clinical evaluation.