Short Term Spironolactone for Prevention of Acute Kidney Injury After Cardiac Surgery

Adult patients (\>18 years old) were eligible for the study if they were undergoing elective or emergency cardiac surgery requiring CPB and aortic cross clamp. Exclusion criteria were patients with preoperative chronic renal insufficiency (Serum creatinine \>1.6 mg/dl) or on dialysis, hyperkalemia (\>5.0 mEq/L), AKI detected up to 24 hours before the procedure; patients receiving contrast agents 72 hours before surgery, planned off-pump cardiac surgery, hypersensitivity, allergy or known intolerance to spironolactone and pregnancy. Patients that died during the surgical procedure or 24 hours after surgery were eliminated from the analysis, as well as patients that did not receive spironolactone during the postoperative period. Criteria for stopping spironolactone were serum potassium \>5.5 mEq/L, a serum creatinine level ≥2.5 mg/dL and urine output of \<0.3 ml/k/hr during 8 hours. One day prior to the procedure, patients that met the inclusion criteria were invited to participate in the trial, signing an informed consent. Spironolactone was administered orally by a study investigator (100 mg 12-24 hrs before surgery); subsequently three further doses of 25 mg were administered orally in postoperative days 1, 2 and 3. Thus, a total 1 x 100 mg and 3 x 25 mg doses of spironolactone in the intervention group were be given. If the patient had not been extubated, spironolactone was administered nasogastrically. Oral drugs were delayed by up to 4 hours if extubation had just occurred. The patients that decided not to receive spironolactone were followed during the study period and considered as controls. Preexisting ACE inhibitor, angiotensin receptor blocker, or MR antagonist were not suspended before surgery.