Intestinal ischaemia following cardiac surgery: a multivariate risk model.

OBJECTIVE Intestinal ischaemia following cardiac surgery is a serious complication, which carries a high mortality rate. Several studies have examined pre-operative and intra-operative risk factors. We aimed to develop a multivariate risk model to identify those patients at highest risk of intestinal ischaemia. METHODS Data was prospectively collected for 10,976 consecutive cardiac surgery patients from our institution between April 1997 and March 2004. Fifty (0.5%) patients developed post-operative intestinal ischaemia. A forward stepwise multivariate logistic regression analysis was undertaken to identify predictors of developing intestinal ischaemia. Intra-operative and post-operative variables were censored at the time of onset of intestinal ischaemia. RESULTS The predictors of post-operative intestinal ischaemia were: post-op inotrope and dialysis support (OR 6.7; p < 0.001), post-op ventilation >48 h (OR 5.1; p < 0.001), age at operation (OR 1.06 [for each additional year]; p < 0.001), post-op atrial fibrillation (OR 2.3; p = 0.014) and blood loss in intensive care unit (ICU) >700 ml (OR 2.0; p = 0.037). The predictive ability of this model was very good with an area under the receiver operating characteristic curve of 0.93. In-hospital mortality for the patients who developed intestinal ischaemia was 94% (47/50) compared to 3.6% (390/10,926) for the other patients (p < 0.001). CONCLUSIONS Although the incidence of intestinal ischaemia following cardiac surgery is low, the prognosis for these patients is very poor. We have identified several risk factors, and developed a multivariate prediction tool, which may be useful in identifying patients at high-risk of developing intestinal ischaemia.