Acute renal failure following cardiac surgery

Area of Science:

• Nephrology
• Cardiology
• Cardiovascular Surgery

Background:

• Cardiac operations carry a risk of acute renal failure (ARF) and renal dysfunction (RD).
• Preoperative left ventricular dysfunction and prolonged cardiopulmonary bypass (CPB) are identified as significant predictors of postoperative renal complications.
• CPB pressure itself is not a predictor of RD/ARF.

Purpose of the Study:

• To evaluate the incidence of ARF and RD in patients undergoing cardiac operations.
• To identify predictors of postoperative renal dysfunction.
• To assess the effectiveness of low flow, low pressure CPB in preserving renal function.

Main Methods:

• A prospective study of 204 patients undergoing cardiac operations.
• Analysis of preoperative factors and CPB parameters.
• Physiological and clinical studies in 51 selected patients to evaluate CPB techniques and renal function.
• Monitoring of glomerular filtration rate (GFR) and cardiac function postoperatively.

Main Results:

• 2.5% of patients developed ARF, and 2.5% had documented RD.
• Preoperative left ventricular dysfunction and prolonged CPB were associated with increased risk of RD/ARF.
• Low flow, low pressure CPB demonstrated effectiveness in preserving postoperative renal function.
• Patients with ARF had a 65% mortality rate, while those with severe RD without ARF had a 17% mortality rate.

Conclusions:

• Cardiac surgery patients are susceptible to renal dysfunction, particularly those with preoperative left ventricular dysfunction or requiring prolonged CPB.
• Low flow, low pressure CPB appears to be a protective strategy for renal function.
• Further insults on already compromised kidneys are often required for the development of ARF.