Hypothermic circulatory arrest and hypothermic perfusion for extensive disease of the thoracic and thoracoabdominal aorta.

Abstract

Hypothermic cardiopulmonary bypass with or without an interval of circulatory arrest has been evaluated for the treatment of complex aortic disease of the descending thoracic and thoracoabdominal aorta. Hypothermia has a protective effect on spinal cord function, and its use should reduce the incidence of paraplegia and paraparesis in traditionally high-risk patients. Experimentally, the protective effect of hypothermia has been related to amelioration of excitotoxic injury by reduction of neurotransmitter release and to inhibition of delayed apoptopic cell death. During a 12-year period, 114 patients with descending thoracic or thoracoabdominal aortic disease underwent replacement of the involved aortic segments using hypothermic cardiopulmonary bypass and intervals of circulatory arrest. The mean age of the patients was 60 years (range 22 to 79 years). Acute or chronic dissection was present in 40 patients (35%). Sixty-four patients (56%) had Crawford Types I, II, or III thoracoabdominal aneurysms. The hospital mortality was 8% (9 patients). Paraplegia occured in 2 and paraparesis in 1 of the 108 patients whose lower limb function was assessed postoperatively (2.8%). None of 40 patients with aortic dissection and none of the last 81 patients in the series developed paralysis. One patient developed renal failure that required dialysis. Our experience with hypothermic cardiopulmonary bypass and circulatory arrest confirms that hypothermia provides substantial protection against spinal cord ischemic injury. It allows complex operations on the descending thoracic and thoracoabdominal aorta to be performed with acceptable mortality, a low incidence of renal failure, and an incidence of other complications that does not exceed that reported with other techniques.