Risk factors for intestinal ischaemia in cardiac surgical patients

Mesenteric ischaemia is an uncommon (<1%) but serious complication of cardiac surgery associated with a mortality >50%. Predictors of this complication are not well defined, and diagnosis can be difficult and prompt surgical intervention can be lifesaving.

In a retrospective case-note analysis from May 1994 through to May 2000, we identified mesenteric ischaemia in 39 of 5349 consecutive patients (0.07%) undergoing cardiac surgery with cardiopulmonary bypass. By logistic multivariate analysis, we have identified six possible predictors of intestinal ischaemia: duration of cross-clamp, use of significant inotropic support, intra-aortic balloon counterpulsation for low cardiac output, need for blood transfusions, triple vessel disease and peripheral vascular disease. In all patients a combination of four predictors were present. Patients who survived this complication had surgical intervention earlier (6.4+/-3.8 h) than those who did not (16.9+/-10 h).

The diagnosis and prompt treatment of mesenteric ischaemia post cardiac surgery requires a high degree of awareness. These predictors may be useful in alerting medical staff to the possibility of gastro-intestinal ischaemic complications after cardiac surgery particularly that early surgical intervention reduces mortality.