Recognition of an unsuspected phaeochromocytoma during elective coronary artery bypass surgery.

A patient with a longstanding history of mild hypertension undergoing elective coronary artery bypass grafting exhibited extreme and paroxysmal elevations of systemic blood pressure immediately after separation from cardiopulmonary bypass. Conventional antihypertensive therapy (nitroprusside, hydralazine, propranolol) was ineffective, whereas phentolamine infusion produced a decrease in systemic blood pressure. These observations led to the discovery of a predominantly norepinephrine-secreting phaeochromocytoma. This case is noteworthy in that cardiopulmonary bypass may have served as a stimulus for tumour secretion of catecholamine. Possible mechanisms for this effect are discussed.