Gastrointestinal complications after cardiac surgery are often difficult to diagnose, and are associated with high morbidity and mortality rates. The aim of this study was to determine risk factors for these complications.

Between 1996 and 2001 data were collected prospectively from 6119 patients who underwent 6186 cardiac surgical procedures. Data from patients who experienced major gastrointestinal complications were analysed retrospectively by univariate and multivariate analysis.

Fifty major gastrointestinal complications were identified in 47 patients (incidence 0·8 per cent). Thirteen of these patients died within 30 days. The most common complication was upper gastrointestinal bleeding (16 patients). Intestinal ischaemia was the most lethal complication (eight of ten patients died). Abdominal surgical operations were performed in 12 patients. Multivariate analysis identified nine variables that independently predicted major gastrointestinal complications: age over 80 years, active smoker, need for preoperative inotropic support, New York Heart Association class III–IV, cardiopulmonary bypass time more than 150 min, postoperative atrial fibrillation, postoperative heart failure, reoperation for bleeding and postoperative vascular complications.

Nine risk factors for the development of major gastrointestinal complications after cardiac surgery were identified. Gastrointestinal complications were often lethal but did not independently predict death within 30 days.