MODERATE HYPOTHERMIA, WITH PARTIAL BYPASS AND SEGMENTAL SEQUENTIAL REPAIR FOR THORACOABDOMINAL AORTIC-ANEURYSM

Purpose: Ischemic injury to the spinal cord, kidneys, and viscera occu rs in a significant number of patients undergoing surgical repair of t horacoabdominal aortic aneurysms. Partial bypass has been used to perf use the arterial system distal to the cross-clamp, but the primary det erminant of ischemic morbidity remains the duration of aortic cross-cl amping. Hypothermia may favorably affect outcome during these procedur es, but moderate or deep hypothermia has traditionally required full c ardiopulmonary bypass with cardiac arrest. Methods: In a series of pat ients undergoing thoracoabdominal (n = 14) or thoracic (n = 4) aneurys m repair, we used moderate hypothermia (30 degrees C) and partial bypa ss (aortofemoral or atriofemoral) while maintaining an intrinsic cardi ac rhythm. Body temperature was controlled with a heat exchanger in th e bypass circuit, which allowed for rapid cooling and rewarming. In ad dition to hypothermia and bypass, a segmental sequential surgical repa ir was used to minimize the duration of ischemia to any given vascular bed. Results: All patients survived the surgical procedure, and 16 pa tients survived until discharge from the hospital. None of the 18 pati ents had paraplegia or significant renal dysfunction. The only complic ation related to hypothermia was atrial fibrillation, which occurred i n three patients and was amenable to therapeutic measures. Conclusions : We conclude that moderate hypothermia, partial bypass, and segmental sequential repair may reduce ischemic injury. This combination of adj uncts was not associated with significant complications in this series of patients.