Neurologic and neuropsychological morbidity following major surgery: comparison of coronary artery bypass and peripheral vascular surgery.

As part of a prospective study of the neurologic and neuropsychological complications of coronary artery bypass graft surgery, 312 patients were compared with a control group of 50 patients undergoing major surgery for peripheral vascular disease. The purpose of comparing the 2 groups was to determine to what extent neurologic complications after heart surgery can be attributed to cardiopulmonary bypass. The 2 groups were similar with respect to age, preoperative neurologic and intellectual status, anesthetic methods, duration of operation, perioperative complications, and time spent in the intensive therapy unit. Certain potential risk factors for cerebrovascular disease were more common in the control than the coronary bypass patients. The important difference between the 2 groups was that only the latter group underwent cardiopulmonary bypass. In this group 191 of 312 (61%) and 235 of 298 (79%), respectively, developed early neurologic and neuropsychological complications. By the time of hospital discharge 17% had neurologic disability and 38% had significant neuropsychological symptoms. In the control group 9 of 50 (18%) developed neurologic complications resulting largely from trauma to lower limb sensory nerves. Two patients developed primitive reflexes. Fifteen of 48 (31%) showed neuropsychological impairment on 1 or 2 subtest scores. Moderate or severe intellectual dysfunction was not seen in the control patients in contrast to the 24% thus affected in the coronary bypass group. The difference in frequency and severity of central nervous system complications between the 2 groups is likely to reflect cerebral injury resulting from cardiopulmonary bypass.