Surgically remediable cardiovascular complications are common in patients with renal failure treated by dialysis. 20 such patients were operated in our department (16 men and 4 women), aged 27 to 61 years (mean 44.5 years). 12 patients had undergone haemodialysis for 1 to 84 months; 4 patients were treated by peritoneal dialysis; the remaining four patients all had severe renal failure with creatinine clearances of less than 10 ml per minute. All patients were operated immediately after a session of dialysis. Particular attention was paid to preserving the peripheral arterial and venous vessels during anaesthesia and cardiopulmonary bypass. The jugular veins were used whenever possible to spare the upper limb veins and the dorsalis pedis arteries were used for the monitoring of systemic blood pressure to spare the radial arteries for eventual arteriovenous fistulae. Weight gain during the operation was limited by cardiopulmonary bypass techniques. The circuit was filled with 200 cc of B 21, 500 cc of isotonic bicarbonate solution and 800 cc of frozen plasma with potassium supplements. Mean weight gain was moderate (1.1 +/- 0.4 kg). 12 patients underwent valve replacement. The surgical indication was acute endocarditis in 6 cases. The aortic valve was replaced in 10 cases and the mitral valve in 2 cases by mechanical valve prostheses because of the high risk of calcification of bioprostheses in severe renal failure. 8 patients underwent coronary bypass graft surgery. Arterial blood pressure was maintained at over 60 mmHg and large doses of heparin were used to protect the arteriovenous shunts.(ABSTRACT TRUNCATED AT 250 WORDS)