[Heart surgery with cardiopulmonary bypass in patients on chronic dialysis treatment: our experience]

To determine the mortality and the morbidity of cardiac surgery in patients on chronic hemodialysis, we retrospectively reviewed eighteen adult patients (13 males and 5 females) with a mean age of 54.7 years (range: 30-67 years) who underwent cardiopulmonary bypass procedures between 1987 and 1995. The operations included: isolated coronary artery bypass grafting in 12 patients, coronary artery bypass grafting plus mitral ring annuloplasty in 1 patient, mitro aortic valve replacement in 2 patients, isolated aortic valve replacement in 1 patient, aortic valved conduit implantation in 1 patients and mitral valve replacement plus tricuspid annuloplasty in 1 patient. There were 10 and 3 patients in CCS functional classification III and IV respectively; 1 and 4 patients were in NYHA classification II and III respectively. All of them were hemodialyzed the day before surgery: the average time they had been on hemodialysis was 6.5 years. Anesthesia and the cardiopulmonary bypass (CPB) in these patients required attention in order to provide the optimal fluids and electrolytes balance: particularly intravenously administered fluids were kept to a minimum and drug dosages were reduced to recommended levels for anephric patients. An hemoconcentrator was used in all patients during the CPB and, in the last 4 cases, we used a dialysis filter and a sterilized perfusional solution to reduce the level of potassium and to put off postoperative dialysis.

In three patients there were major bleeding problems resulting in reoperation; 5 perioperative deaths occurred: two of them due to myocardial infarction and three due to irreversible low cardiac output state. In our experience there were four late deaths: one patient died four months after surgery for chronic heart failure, another one died twelve months after surgery for dilated cardiomyopathy and two patients died respectively seventeen and seventy two months after discharge for myocardial infarction. Two of the remaining patients reported recurrence of angina while the others achieved symptomatic improvement.

In conclusion, cardiac surgery is performed on chronic renal dialysis patients with high mortality and morbidity and it's indicated only if medical treatment is ineffective. The successful surgical results, obtained with an adequate management between surgeons, anesthesiologists and nephrologists, don't assure the long-term survival of the patients.