Survival after surgery with cardiopulmonary bypass in low weight patients.

To evaluate risk factors for hospital death in patients weighing < 2.5 kg undergoing open-heart surgery, records of 34 consecutive low-weight patients operated on between December 1997 and November 2004 were reviewed. Mean weight was 2.152 +/- 0.237 kg (range, 1.600 to 2.460 kg). Biventricular repair was achieved in 28 patients. The most frequent procedures were the arterial switch operation in 9 children, ventricular septal defect closure in 6, repair of total anomalous pulmonary venous connection in 5 and truncus arteriosus repair in 5. There were 8 early deaths. Mortality was strongly associated with the Comprehensive Aristotle Complexity Score: mortality was low (2/27; 7.4%) with a score < 19, and high (6/7; 85.7%) with a score >/= 19. Higher mortality was encountered after univentricular repair (4/6; 67%). Hyperlactatemia at the end of cardiopulmonary bypass was also associated with poor survival. A Comprehensive Aristotle score < 19 was the strongest predictor of survival in low-weight patients undergoing open-heart surgery. Biventricular repair, when feasible, should be promoted to improve outcome.