Objective: The objective of this study was to validate the usefulness of retroperitoneal hematoma volume as a predictor of perioperative mortality after endovascular aneurysm repair (EVAR) for ruptured abdominal aortic aneurysm (rAAA). Methods: We retrospectively reviewed consecutive patients with rAAA who underwent the unified EVAR first protocol between 2012 and 2016 at any one of three participating institutions in Japan and were prospectively registered in a dedicated database. Only patients with preoperative computed tomography scans adequate for three-dimensional volumetric analysis were included. Volumetry was used to measure the retroperitoneal hematoma volume. To adjust for body size differences between patients, the retroperitoneal hematoma volume was divided by the abdominal cavity volume, and the predictive power of this ratio was validated using appropriate statistical methods. Results: Of 114 patients with rAAA managed during the study period, 101 (88.6%) underwent EVAR, 9 (7.9%) underwent open surgical repair, and 4 (3.5%) did not undergo any repair. Finally, 82 of 101 patients treated with EVAR were included in the analysis. Within 30 days after EVAR, the mortality rates for the 82 patients included in the analysis and the 19 excluded patients were 24.4% and 31.6%, respectively, without statistically significant differences (P =.518). The retroperitoneal hematoma volume ratio was 3.59% ± 2.46% and 7.63% ± 3.45% in survivors and nonsurvivors, respectively (P <.001). Univariate analysis of other preoperative demographic and anatomic factors revealed that a Glasgow Aneurysm Score >85, systolic blood pressure <90 mm Hg, loss of consciousness, and mean minimum right external iliac artery diameter were statistically significant. Receiver operating characteristic curve analysis for the prediction of perioperative mortality revealed that retroperitoneal hematoma volume ratio was the best predictor of perioperative mortality in patients with rAAA of type >III in the Fitzgerald classification (area under the curve: retroperitoneal hematoma volume ratio, 0.880; Glasgow Aneurysm Score, 0.587; P <.001). Based on the Youden index, the optimal cutoff for the retroperitoneal hematoma volume ratio was 6.97%, providing a sensitivity of 0.833 and specificity of 0.860. Conclusions: Our study suggests that retroperitoneal hematoma volume may be a good predictor of perioperative mortality after EVAR for rAAA, especially for patients with Fitzgerald classification >III and a best cutoff value of 6.97%.
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