Surgery and Anesthesiology – Renal Complications
Renal Dysfunction After Myocardial Revascularization; Risk Factors, Adverse Outcomes and Hospital Resource Utilization
Ann Intern Med 128: 194-203, 1998
The effects of Cardiac surgery on renal function remain unclear. Renal function abnormalities can result from nonpulsatile blood flow, increased catecholamine and inflammatory mediator levels, renal embolic insults and release of free hemoglobin from traumatized erythrocytes. Renal function was studied in a large population of patients undergoing cardiopulmonary bypass and myocardial revascularization.
The study included 2222 patients undergoing myocardial revascularization at 24 research hospitals. Their rates of postoperative renal failure [defined as a need for dialysis] and of renal dysfunction [defined as a postoperative serum creatinine level of 177 (mol/L or greater and an increase in serum creatinine of 62 (mol/L or greater from the preoperative to postoperative period] were assessed.
Postoperative renal dysfunction ocurred in 7.7% and renal failure in 1.4% of patients. The mortality rate of 0.9% for patients with no renal complications was 19% for those with renal dysfunction and 63% for those with renal failure. The risk of renal failure increased with age: it doubled for those in their 70s and trebled for those in their 80s. Factors associated with renal dysfunction were Type I diabetes mellitus, a preoperative glucose level of greater than 16.6 (mol/L. Congestive heart failure, previous coronary bypass grafting and a preoperative creatinine level of 124 to 177 ( mol/L. More than 80% of patients with renal dysfunction had intraoperative or postoperative hemodynamic instability or hemorrhage.
The study shows an 8% rate of renal dysfunction or failure in patients undergoing myocardial revascularization. Renal risk is associated with patient related factors, probably reflecting diffuse atherosclerosis. These findings have implications for preoperative communication of risk, treatment with potential nephrotoxic drugs and surgical technique.