Risk factors of postoperative nephropathy in patients undergoing innovative CABG and intraoperative graft angiography

Abstract

Intraoperative graft angiography is considered gold standard in quality control of innovative CABG techniques. Iodixanol, an iso-osmolar, non-ionic contrast agent has been safely applied in patients with impaired renal function. We aimed to quantify postoperative nephropathy in CABG patients undergoing intraoperative angiography and to define associated risk factors. One hundred and thirty-five patients, aged 61 years (range: 43-83), underwent intraoperative angiography following CABG (36 robotically assisted CABG via sternotomy, 41 OPCAB and MIDCAB, 51 AHTECAB, 7 BHTECAB). In all patients iodixanol (Visipaque) was used, median amount: 150 ml (range: 20-500). Nephropathy was defined as an increase in serum creatinine concentration >or= 0.5 mg/dl compared with preoperative values. Nephropathy occured in 19/135 (14%) patients, and was correlated with the following variables: preoperative serum creatinine (p = 0.015, r = 0.208), age (p = 0.008, r = 0.229), postoperative peak troponin T levels (p < 0.001, r = 0.545), postoperative CK-MB peak levels (p = 0.028, r = 0.189), and presence of peripheral vascular disease (p = 0.011). No correlation was found for the contrast agent amount, diabetes mellitus, hypertension, preoperative urea level, cardiopulmonary bypass time, aortic cross clamp time, postoperative CK peak levels. Multivariate analysis showed that postoperative peak troponin T levels (p < 0.001), preoperative serum creatinine (p = 0.031), and patient age (p = 0.043) were independently associated with a postoperative increase of serum creatinine. In all 19 patients with postoperative nephropathy serum creatinine levels returned to preoperative levels. Patients with older age and elevated serum creatinine levels undergoing innovative CABG and intraoperative angiography were at increased risk of postoperative nephropathy. However, no correlation was found between the amount of contrast agent (iodixanol) applied and the nephropathy rate and none of the nephropathy cases persisted.