Abdominal Compartment Syndrome After Abdominal Aortic Aneurysm Repair: Subgroups, Risk Factors and Outcome

Abstract

Introduction - Abdominal compartment syndrome (ACS) remains a lethal complication after abdominal aortic aneurysm (AAA) repair. The aim of this population-based cohort study was to investigate factors associated with outcome. Methods - Since 2008, postoperative ACS and decompression laparotomy after AAA repair are registered prospectively in the National vascular registry. The case records of all patients registered for ACS 2008-2015 were reviewed. The main pathophysiological mechanism seen at laparotomy was defined and the duration of intra-abdominal hypertension (IAH) prior to decompression was registered. Results - In all 119 patients from 24 vascular centres were included in the study. Among 82 repairs for ruptured AAA (rAAA), there were 44 Open surgical repairs (OSR) and 38 endovascular aortic repair (EVAR), and among 37 repairs for intact AAA (iAAA), there were 30 OSR and 7 EVAR. Mortality did not differ between EVAR and OSR for rAAA but was higher after EVAR for iAAA at one-year (6/7 [85.7%] versus 9/30 [30.0%], p=.011). Patients treated with EVAR for rAAA reached peak intra-abdominal pressure (IAP) values, and had DL earlier, than those treated with OSR (Both p<.001). Decompressive laparotomy (DL) was performed within twenty-four hours in 55 (48.2%) patients, between twenty-four and forty-eight hours in 30 (26.3%) and after forty-eight hours in 29 (25.4%). There were three main findings at DL: bowel ischemia in 27 (23.5%), postoperative bleeding in 34 (29.6%) and general oedema/fluid overload in 54 (47.0%). Mortality did not differ depending on findings at DL, figure 1, or timing of DL. Ninety-day non-survivors (60/119, 50.4%) were older (p<.001), had larger aneurysms (p=.045), received more intraoperative blood transfusions (p=.001) and were more often treated with suprarenal clamping/balloon occlusion (p<.001), compared to those who survived 90 days or longer after surgery. In multivariable regression analysis, only age was a predictor for one-year mortality (p=.026). Duration of intra-abdominal pressure ≥15 and ≥20 mmHg prior to DL were independent predictors for the need of renal replacement therapy (RRT) (p=.041 and p=.031). Open abdomen treatment was performed in 106 patients of whom 98 (92.5%) received negative pressure wound therapy (NPWT), which in a majority also was combined with mesh-mediated traction. Among 85 patients with NPWT who survived until the abdomen was closed, 81 (95.3%) achieved primary delayed fascial closure. Conclusion - Mortality in ACS did not differ depending on the cause of ACS or on whether DL was performed early, intermediate or late. The duration of IAH prior to DL affected the need for RRT, suggesting the value of close monitoring and early treatment of IAH to prevent renal failure. ACS after EVAR for rAAA developed early after surgery, and in this clinical scenario monitoring of IAP may be life-saving.