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INTRODUCTION:
Infrarenal aortic cross-clamping is the preferred method of proximal control when achievable due to the risk of renal ischemia and subsequent renal failure associated with suprarenal clamping. However, suprarenal control is increasingly becoming necessary during open repair of aortic pathology given the increasing use of endovascular therapies. The purpose of this study was to evaluate morbidity and mortality with emphasis on the risk of renal dysfunction associated with suprarenal aortic clamping.
METHODS:
A retrospective chart review of all patients undergoing aortic surgery requiring supra renal clamping from January 1990 to April 2016 at a single center, by a single surgeon was performed. Primary endpoints included renal dysfunction and perioperative morbidity and mortality. Survival was estimated by Kaplan-Meier methods and patient demographics and peri-operative factors were analyzed using both univariate and multivariate analysis.
RESULTS:
103 patients requiring supra renal clamping were identified over this time period, with an average age of 68.7 years, and a male predominance (99%). The indication for surgery was aneurysm in 92% with a mean size of 6.4 cm. Pre-operative demographics included creatinine of 1.1 mg/dl, CAD in 54%, COPD in 29%, and previous MI in 26%. Intraoperative features included length of procedure 211 min, mean suprarenal clamp time of 20 min and EBL of 3 liters. Post-operative complications occurred in 35%. 55 patients (53.3%) developed transient renal dysfunction (defined as a creatinine increase >10%), of which only 3 patients (2.9%) required dialysis postoperatively. LOS was 18 days, 81% were discharged to home. Mean follow up was 311 days, 30 day mortality was 5.8%. Factors associated with post-operative renal dysfunction on univariate analysis included age (p = 0.014), increased preoperative creatinine level (p < .001), history of smoking (current smoker, p = .009, ex-smoker, p = .032), coronary artery disease (p = .005), Coumadin use (p = .05), supra renal clamp time (22.1 vs. 18.1 minutes, p = .035), aneurysm size (6.6 vs. 6.0 cm, p = .045), elevated post-operative troponin (p = .009) and increased intraoperative blood loss (p <.001). On multi-variate analysis, aneurysm size (p = .045), age (p = .02) and smoking status (p = .042) persisted. Factors associated with increased perioperative morbidity included length of operation (p= 0.013) and increased blood loss (p= 0.028). Multivariate analysis on mortality was significant for supraceliac clamp location (p = .018) increased estimated blood loss (p = .011), elevated pre-operative creatinine (p<.001) and elevated post-operative troponin (p <.023). Overall survival at 1, 5, and 10 years was 75%, 39%, and 12% respectively.
CONCLUSIONS:
During procedures for aneurysm or aortoiliac occlusive disease, suprarenal clamping can be performed safely with good results and a majority of patients returned home. It does result in renal dysfunction in over 50% of patients. However, the majority of patients recover renal function during the course of their hospitalization with only a small percentage of patients (2.9%) requiring post-operative dialysis. We believe that these data represent a series that can be used for evaluation and comparison against suprarenal endovascular procedures.