Hypothermic cardiopulmonary bypass for spinal cord protection: Rationale and clinical results

Background. Hypothermic cardiopulmonary bypass with or without circulatory arrest has been used successfully for the treatment of complex aneurysms of the descending thoracic and thoracoabdominal aorta. Hypothermia has a prot ective effect on spinal cord function, and its use has been associated with a low incidence of paraplegia in traditionally high-risk patients. Experim entally, the protective effect of hypothermia has been related to ameliorat ion of excitotoxic injury by reduction of neurotransmitter release and to i nhibition of delayed apoptotic cell death. Methods. During a 12-year period, 114 patients with descending thoracic or thoracoabdominal aortic disease underwent replacement of the involved aorti c segments using hypothermic cardiopulmonary bypass and intervals of circul atory arrest. Results. The hospital mortality was 8% (9 patients). Parapleg ia occurred in 2 and paraparesis in 1 of the 108 patients whose lower limb function was assessed postoperatively (2.8%). None of 40 patients with aort ic dissection and none of the last 81 patients in the series developed para lysis. Conclusions. Our experience with hypothermic cardiopulmonary bypass and cir culatory arrest confirms that hypothermia provides substantial protection a gainst paraplegia, and it allows complex operations on the descending thora cic and thoracoabdominal aorta to be performed with acceptable mortality. ( C) 1999 by The Society of Thoracic Surgeons.