LAUSR

BACKGROUND Abdominal compartment syndrome (ACoS) is a devastating complication after endovascular aneurysm repair for ruptured abdominal aortic aneurysms (rEVAR). This study sought to develop a risk score for ACoS to identify patients who would benefit from early decompressive laparotomy. METHODS Model derivation was performed with VQI data for rEVAR from 2013-2020. The primary outcome was evacuation of abdominal hematoma. Multivariable logistic regression was used to create and validate a scoring system to predict ACoS. The model was validated using institutional data for rEVAR from 1998-2019. RESULTS The derivation cohort included 2,310 patients with rEVAR. Abdominal hematoma evacuation occurred in 265 patients (11.5%). Factors associated with abdominal hematoma evacuation on multivariable analysis included transfer from an outside hospital, preoperative creatinine ≥1.4 mg/dl, preoperative systolic blood pressure ≤85 mmHg, preoperative altered mental status, ≥3.0 liters intraoperative crystalloid, and ≥4 units of red blood cells transfused intraoperatively. The validation cohort consisted of 67 rEVAR; ACoS occurred in 8 patients (11.9%). The c-statistic was 0.84 in the derivation and 0.87 in the validation cohort, while Hosmer-Lemeshow was p= 0.15 in the derivation and 0.84 in the validation cohorts, suggesting good model discrimination and calibration. Points were applied based on β-coefficients to produce a risk score ranging from -1 to 13. A cutoff of risk score ≥8 resulted in a sensitivity and specificity of 87.5% and 83.1% for detecting patients with ACoS, respectively. ACoS conveyed a significantly higher mortality in both the derivation (ACoS: 49.8% vs No ACoS: 17.8%; p<0.001) and validation cohorts (ACoS: 75.0% vs No ACoS: 15.2%; p<0.001). CONCLUSION In patients with equivocal signs/symptoms of ACoS, this scoring system can be used to guide surgeons on when to perform decompressive laparotomy prior to leaving the operating room for rEVAR. Patients with a risk score ≥8 would benefit from decompressive laparotomy at index rEVAR.