Cardiovascular surgery in the hypothyroid patient.

The management of hypothyroid patients requiring major cardiovascular surgery is difficult and often controversial. We prospectively studied 500 patients requiring cardiac surgery with cardiopulmonary bypass and found ten with previously undiagnosed mild to moderate hypothyroidism. All ten tolerated surgery well without preoperative thyroid hormone replacement. Our experience with these patients plus an additional five seen in our clinical practice suggests that major cardiovascular surgery can be performed safely in most patients with mild to moderate hypothyroidism. We conclude that untreated hypothyroidism in patients with ischemic heart disease should not be an absolute contraindication to coronary artery bypass surgery.