Open surgical abdominal aortic aneurysm (AAA) repair (OSR) is often reserved in contemporary practice for complex aneurysms requiring supra-renal or supra-celiac proximal clamp level. This study investigates the associated 30-day outcomes of different proximal clamp levels in OSR of complex infra-renal/juxta-renal AAA in patients with normal renal function and those with chronic renal insufficiency (CRI).
All patients undergoing elective OSR of infra-renal and juxta-renal AAA were identified in the American College of Surgeons – National Surgical Quality Improvement Program (ACS-NSQIP) Targeted-AAA database from 2012-2018. Patients were stratified into two cohorts: normal renal function (eGFR≥60ml/min) and CRI (eGFR <60ml/min; non-dialysis), before further sub-stratification into groups by proximal clamp level (infra-renal, inter-renal, supra-renal, and supra-celiac). Rates of 30-day outcomes including mortality, renal and pulmonary complications, and major adverse cardiovascular events (MACE) were compared within each renal function cohort between proximal clamp level groups using the infra-renal clamp group as reference. Supra-celiac clamping was also compared to supra-renal clamping.
There were 1284 normal renal function and 524 CRI patients. Proximal clamp levels were: infra-renal (n=1080; 59.7%), inter-renal (n=337; 18.6%), supra-renal (n=279; 15.4%), and supra-celiac (n=112; 6.2%). In the normal renal function cohort, there was no difference in 30-day mortality with any clamp level. Increased 30-day acute renal failure was only observed with the supra-celiac versus infra-renal clamp level comparison (5.9% vs. 1.5%; aOR=3.97; 95% CI=1.04-5.18; P=.044). In the CRI cohort, supra-celiac clamping was associated with increased renal composite complications (22.7% vs. 5.6%; aOR=8.81; 95% CI=3.17-24.46; P<.001), and ischemic colitis (13.6% vs. 3.0%; aOR=4.78; 95% CI=1.38-16.62; P=.014) versus infra-renal clamping, and greater 30-day mortality (13.6% vs. 2.4%; aOR=6.00; 95% CI=1.14-31.55; P=.034) and renal composite complications (22.7% vs. 10.8%; aOR=2.87; 95% CI=1.02-8.13; P=.047) versus supra-renal clamping. Supra-renal clamping was associated with greater renal dysfunction (10.8% vs. 5.6%; aOR=2.77; 95% CI=1.08-7.13; P=.035) versus infra-renal clamping, with no difference in mortality. Inter-renal clamping had no difference in 30-day mortality or morbidity versus infra-renal clamping in either cohort. There was no difference in MACE with higher clamp levels in either cohort.
In elective OSR of infra-renal and juxta-renal AAA for CRI patients there is a heightened mortality risk with supra-celiac clamping, and increased renal morbidity with supra-renal clamping, which are not present in normal renal function patients. Every effort should be made to keep proximal clamp level as low as possible, particularly in CRI patients.

Copyright © 2020. Published by Elsevier Inc.