A thousand pericardial valves in aortic position: risk factors for postoperative acute renal function impairment in...

Postoperative renal dysfunction after aortic valve replacement is a serious complication. To minimize its occurrence, risk factors have to be identified, and if possible eliminated.

Of 1000 consecutive patients, who underwent AVR, a file study was performed chi(2)nd logistic regression analysis were performed to study the effect of 24 preoperative, 7 peroperative and 7 postoperative factors on the occurrence of 30-day postoperative worsening of renal function.

Fifty-three patients had a 30-day postoperative decrease of renal function. Nine of these patients died, which is significantly more than the mortality without this complication (P<0.0001). In those nine patients, another complication (postoperative heart failure, thromboembolism or respiratory failure) was present. Thirteen factors were significant in an univariate analysis: preoperative renal dysfunction (P<0.001), age>80 (P<0.001), atrial fibrillation (P<0.001) , preoperative pulmonary edema (P=0.001), conduction defect (P=0.002), diabetes (P=0.006), myocardial infarction (P=0.006), postoperative heart failure (P=0.007), cross clamp time >75 min (P=0.015), previous coronary artery bypass grafting (CABG) (P=0.018), concomitant CABG (P=0.031), ejection fraction <50% (P=0.033) and CVA (P=0.035). Four factors were identified as independent predictors in a multivariate analysis: renal dysfunction (P<0.001, Odds ratio [OR] 5.5; 95% confidence interval [CI] 2.9-10.4), preoperative atrial fibrillation (P=0.010, OR=2.3, 95% CI=1.2-4.2), age>80 (P=0.014, OR=2.2, 95% CI=1.2-4.1) and myocardial infarction (P=0.022, OR=2.2, 95% CI=1.1-4.4).

Few factors are liable for therapeutic intervention, especially in elderly and patients with comorbidity. In patients with risk factors, shortening of cross clamping time or installation of minimal extracorporeal circulation might be beneficial.