According to a new study, the rate of renal morbidity following either fenestrated endovascular aortic aneurysm repair (EVAR) or branched EVAR is low. However, through a univariate analysis, the study showed that branched EVAR was associated with a significantly increased rate of renal composite events than fenestrated EVAR.
Presenting the data at the European Society for Vascular Surgery meeting (23–26 September, Stockholm, Sweden), Teresa Martín González (CHRU, Université Lille Nord de France, Lille, France) said that although postoperative renal impairment was one of the most common complications after complex EVAR, long-term renal outcomes following complex EVAR were “poorly described”. Therefore, she and her co-authors conducted the study to “analyse the immediate and long-term renal outcomes—renal function and renal events—after fenestrated EVAR and branched EVAR in a high-volume centre.”
Martín González, using data from hospital chart reviews, examined outcomes following all fenestrated and branched EVAR procedures that took place at their centre between October 2002 and October 2012. They defined acute renal failure by the RIFLE (Risk, injury, failure, loss, endstage renal disease) criteria, and assessed renal volume and the estimated glomerular filtration rate (eGFR) before the procedure, before discharge, 12 months after the procedure and yearly thereafter. Additionally, there was a composite endpoint of renal outcomes that included occlusion, dissection, stenosis, endoleak, fracture, kinking and secondary procedures.
The investigators identified 225 patients who had undergone fenestrated or branched EVAR during the study period, which represented 433 target vessels that had been treated (374 fenestrations; 53 branches). The average follow-up period was 3.1 years.
Sixty-four (29%) patients developed postoperative acute renal failure and 13 (5.9%) of these patients required haemodialysis with one requiring permanent haemodialysis. Martín González reported: “There was a significantly increased risk of mortality before six months in patients who had acute renal failure and required haemodialysis.” She added that another four patients required haemodialysis during follow-up but that all of these patients had established chronic kidney disease prior to the fenestrated/branched EVAR procedure, commenting that “preoperative chronic kidney disease was associated with an increased risk of acute renal failure (p<0.0001).” In the overall study population, the freedom from renal composite events was 98.1%, 95%, and 87.5% at 30 days, one year, and five years after the procedure, respectively.
A comparison between patients who underwent fenestrated EVAR and those who underwent branched EVAR found that significantly more patients in the branched EVAR group had preoperative renal stenosis (p<0.021). Also, although there was a significant decrease in the eGFR (compared with baseline levels) in the overall patient group (p<0.0001) during the follow-up period, there was a significantly greater decrease in the branched EVAR group compared with the fenestrated EVAR group (p=0.01). Furthermore, in a univariate analysis, there was a significantly higher rate of renal composite events in the branched EVAR group (p=0.02 for the comparison) but this was not confirmed in a multivariate analysis.
Another finding in the study was that (in the overall patient group) renal volume was significantly decreased over time (p=0.0006 for the comparison) and a significantly higher volume decrease was found in patients with a more than 20% decrease in the eGFR during the follow-up period (p=0.03). According to Martín González, these data indicate that renal volume—unlike decrease in renal length, which was not found to be associated with a decrease in eGFR of more than 20%—was as accurate as eGFR as “depicting renal dysfunction during follow-up”. She concluded: “Fenestrated EVAR and branched EVAR are durable options with low renal morbidity.”
Study author Stéphan Haulon told Vascular News: “Acute renal failure following complex EVAR significantly increases early mortality. To reduce the risk of renal failure, routine implementation of a specific perioperative renal protocol is mandatory, especially in chronic kidney disease patients. Our protocol includes acetylcysteine at a dose of 600mg twice daily on the both the day before and the day of operation and saline (0.45%) intravenously at a rate of 1ml per kilogram of body weight per hour for 12 hours before and 12 hours after administration of the contrast agent.”
