Mannitol Use is Renal Protective in Patients with Chronic Kidney Disease Requiring Suprarenal Aortic Clamping

Background: Mannitol is often administered during open juxtarenal or suprarenal aortic sur-gery to prevent ischemic injury to the kidneys. Prior evidence evaluating the benefits of intrao-perative mannitol in reducing ischemia/reperfusion injury is conflicting and largely based on small, retrospective series. The aim of this study was to evaluate the effect of mannitol in pre-venting postoperative hemodialysis in patients undergoing open abdominal aortic aneurysm (AAA) repair where proximal control involved temporary renal ischemia.Methods: The Society for Vascular Surgery Quality Initiative database was queried for all pa-tients undergoing elective open AAA repair between 2003 and 2020. Patients were included in the current analysis if the proximal aortic clamp was placed above at least one renal artery. Chronic kidney disease (CKD) was defined as Cr > 1.8 mg/dL. Primary end points were 30-day major morbidity (myocardial infarction, respiratory complications, lower extremity or in-testinal ischemia, and the need for temporary or permanent hemodialysis) and mortality. Com-parisons were made between the mannitol and nonmannitol cohorts and stratified by the presence of preexisting CKD.Results: During the study period, 4,156 patients underwent elective open AAA repair requiring clamp placement more than one (32.7%) or both (67.3%) renal arteries; 182 patients (4.4%) had preexisting CKD. Overall, 69.8% of patients received mannitol during their surgery. Mannitol was more frequently used in cases involving clamp placement above both renal arteries (70.3%) than one renal artery (61.5%). While prolonged ischemia time (more than 40 min) was associated with a higher risk of postoperative dialysis in patients without CKD, it was not significant in pa-tients with baseline CKD. On a univariate analysis, mannitol use in patients with CKD was asso-ciated with a lower risk of postoperative dialysis (P = 0.005). This remained significant on a multivariate analysis (P = 0.008). Mannitol use did not appear to confer renal protective effects in patients without baseline CKD.Conclusions: Mannitol use was associated with a decreased risk of need for postoperative he-modialysis in patients with CKD undergoing suprarenal aortic clamping for open aneurysm repair. In appropriately selected patients, particularly those with underlying renal insufficiency, mannitol may confer a renal protective effect in open repair of pararenal AAA requiring suprare-nal clamping.

Automated summary

This study evaluated the effect of intraoperative mannitol on preventing postoperative hemodialysis in patients undergoing open AAA repair. Mannitol use was associated with a decreased risk of postoperative dialysis in CKD patients.