Renal function changes after snorkel/chimney repair of juxtarenal aneurysms

Objective: The snorkel approach for endovascular aneurysm repair (EVAR) has been found to be a safe and viable alternative to open repair for juxtarenal abdominal aortic aneurysms with good short-term outcomes. Concerns about long-term durability and renal branch patency with this technique have been raised with the increasing availability of fenestrated devices. We sought to evaluate renal function changes in patients undergoing "snorkel" EVAR (sn-EVAR). Methods: Patients who underwent sn-EVAR from 2009 to 2012 were included in this analysis. Creatinine values were obtained throughout the patient's preoperative, perioperative, and postoperative course. Glomerular filtration rate (GFR) was estimated by the simplified Modification of Diet in Renal Disease formula. Acute renal dysfunction was analyzed according to the RIFLE (Risk, Injury, Failure, Loss, End stage) criteria, whereas chronic renal dysfunction was stratified by the chronic kidney disease staging system. Results: Forty-three consecutive patients underwent sn-EVAR (31 double renal, 12 single renal) for juxtarenal aortic aneurysms. Mean follow-up time was 21 months. Mean aneurysm size was 6.6 cm (range, 5.1-10.5 cm) with anatomy not suitable for treatment with standard EVAR (mean neck length, 1.6 mm); 74 renal snorkel stents were placed in these patients with a 2-year primary patency of 95%. On average, the cohort at baseline was stratified as having moderate renal dysfunction. Mean baseline, maximum postoperative, and latest follow-up creatinine concentrations were 1.20, 1.49, and 1.43, respectively (P = .004). Mean baseline, maximum postoperative, and latest follow-up GFRs were 57.4, 47.8, and 49.2, respectively (P = .014). With use of RIFLE criteria, 14 patients (32.6%) experienced some form of acute kidney injury, although 10 of these patients (23.3%) were classified as mild (25%-50% decline in GFR). On analysis without the RIFLE criteria, 21.4% of patients had postoperative creatinine concentration > 1.5 mg/dL, 28.6% had postoperative creatinine concentration increase > 30%, and 28.6% had postoperative GFR decline > 30%. For the entire study cohort at latest follow-up, 51% experienced no decline of chronic renal dysfunction and 8.1% had improvement in renal function. Renal function declined by one stage in 35.2% of the cohort and by two stages in 5.4%. On analysis without chronic kidney disease staging, 24.3% of patients had latest follow-up creatinine concentration > 1.5 mg/dL, 29.7% had latest follow-up creatinine concentration increase > 30%, and 24.3% had latest follow-up GFR decline > 30%. Mean survival time from significant renal decline was 23.4 months. Conclusions: sn-EVAR continues to demonstrate a high rate of technical success and results in only mild rates of acute and midterm renal function decline according to a number of established definitions for renal dysfunction. Continued monitoring of renal function, renal stent behavior, and abdominal aortic aneurysm sac changes remains critically important in the long-term management of patients undergoing sn-EVAR, particularly given the high comorbidities associated with juxtarenal aortic aneurysms.