Risk of acute kidney injury after minimally invasive transapical aortic valve implantation in 270 patients

Abstract

Contrast agent is a potential risk factor for acute kidney injury (AKI). Little is known about the incidence of contrast-induced nephropathy (CIN) after trans-apical aortic valve implantation (TA-AVI) and on the impact of contrast exposure during preoperative computed tomography (CT) scan and cardiac catheterization. A total of 270 consecutive high-risk patients received TA-AVI for symptomatic aortic valve stenosis during a 3-year period. Different preoperative, peri-procedural, and postoperative variables were analyzed by uni- and multivariate logistic regression concerning incidence of early (<7 days) AKI and need for renal replacement therapy (RRT). Nine patients on chronic preoperative dialysis were excluded. Mean age was 82 ± 5.8 years, 71% were female. LogEuroSCORE (European System for Cardiac Operative Risk Evaluation) and STS Score were 31.4 ± 15.6% and 12.1 ± 7.4%, respectively. Preoperative estimated glomerular filtration rate (eGFR) <60 ml min(-1) was present in 35.2%. CT scan and cardiac catheterization within 7 days before TA-AVI were performed in 43.7% and 20.3% of the patients and were associated with a mean contrast-agent exposition of 110 ± 21 ml for CT scans and 91 ± 65 ml for cardiac catheterization. Regarding the postoperative renal outcome, an improved or at least stable eGFR was seen in more than 50% of the patients. Intra-operative contrast-agent application was 99 ± 64 ml and correlated significantly to the development of postoperative AKI and need for RRT (p=0.013 and p=0.003). Postoperative RRT was required in 15.7%. Chronic renal insufficiency (odds ratio (OR)=6.8, p=0.025) and number of blood transfusions (OR=8.8, p=0.009) were independent risk factors for RRT. Postoperative AKI occurred in 16.1% and intra-operative contrast-agent burden >99 ml (OR=2.3, p=0.038), new thrombocytopenia (OR=4.4, p=0.005) and pathological leucocyte count (OR=2.8, p=0.009) were independent risk factors for this event. Early (within 1-7 days before TA-AVI) preoperative CT and cardiac catheterization did not significantly increase incidence of RRT or AKI. Short-term and long-term survival was explicitly lower in the AKI and in the RRT groups (p<0.001 each). GFR improves after TA-AVI. Postoperative AKI and RRT depend on the amount of intra-operative contrast agent. These results strongly support the need for intra-operative tools to reduce contrast-agent exposition during TA-AVI.