Intraoperative predictors and new risk score for in-hospital mortality in patients undergoing open repair for ruptured abdominal aortic aneurysm

BACKGROUND: The aim of the present study was to identify intraoperative factors affecting early outcomes after open surgical repair (OSR) for ruptured abdominal aortic aneurysms (rAAAs) and to develop and internally validate a novel prognostic risk score for early mortality after OSR for rAAAs (SPARTAN score). METHODS: Three-hundred-sixteen patients were included in the present series from three centers in Italy. Univariate analyses of intraoperative factors affecting in-hospital mortality were performed by means of a log-rank test. Cox regression was applied to all variables with a p level of <0.05. The results of the regression model were presented as the odds ratio (OR) and 95% CI. Independent intraoperative predictors (positive and negative) were used to create a prognostic score for in-hospital mortality. A numerical value of +/-1 was assigned for an approximate OR value of 3. The risk stratification was used to define three subgroups of risk: low, moderate, and high. RESULTS: In-hospital mortality rate was 30.7% (97 cases). Univariate analysis showed hemoperitoneum was the main intraoperative predictor of in-hospital mortality. Suprarenal clamping and operation time >240 min also affected the in-hospital mortality rate. Conversely, the patency of at least one hypogastric artery seemed to have a protective role. The following numerical values could be assigned to the following parameters: +4 hemoperitoneum (OR 13.788); +1 operation time >240 min (OR 4.381); +2 suprarenal clamping (OR 6.187);-2 patency of at least one hypogastric artery (OR 6.450). The risk stratification for in-hospital mortality was carried out by merging the patients with a score value ranging as follows: from-2 to 0: low risk; from 1 to 4: moderate risk; from 5 to 7: high risk. One-hundred-fifty-five patients (49%) could be identified as low risk, 122 patients (38.6%) as moderate risk, and 39 patients (12.4%) as high risk. In-hospital mortality rate was 15.5% for low-risk patients (24 deaths), 39.3% for moderate-risk patients (48 deaths), and 64.1% for high-risk patients (25 deaths). CONCLUSIONS: Hemoperitoneum, suprarenal aortic clamping, and operation time >240 min were negative predictors of in-hospital mortality after OSR for rAAA, whereas the patency of at least one hypogastric artery had a protective role. The SPARTAN risk score may allow surgeons to predict in-hospital mortality stratifying treated patients into three categories (low, intermediate and high risk). Further multicenter experiences with larger population sizes are needed to validate these outcomes in order to create a universal predictive score.