Early risk stratification of acute type A aortic dissection: development and validation of a predictive score.

Abstract

The performance of published preoperative risk scores for acute type A aortic dissection (aTAAD) is suboptimal. So, the predictive power of these scores were externally validated in order to develop and validate a more reliable preoperative score for identification of patients at high risk of mortality. Potential preoperative risk variables of consecutively admitted patients with aTAAD were prospectively collected. Seven published risk scores were validated with our dataset. For derivation and internal validation, the original population was divided at a ratio of 7:3. Logistic regression was used to identify variables for the new score. A 50-patient retrospective dataset was used for external validation. The predictive accuracy for post-operative mortality was evaluated using the area under the receiver operating characteristic (AUROC) curve. During the study period, 225 patients with aTAAD were admitted preoperatively. Of these, 209 underwent surgical repair and 29 died postoperatively. The AUROCs of the seven published pre-operative risk scores for post-operative mortality ranged from 0.57 to 0.77. Four variables were derived for the new score system, i.e., Acute myocardial ischemia, Lactate, Iliac arteries involved, and CreatininE (the ALICE score). The AUROCs for post-operative mortality in the derivation, internal and external validation populations were 0.85, 0.88 and 0.83, respectively. At a cutoff value of 3, the ALICE score for post-operative mortality had a sensitivity of 71% to 88% and specificity of 78% to 86%. The ALICE score comprising four components might help bedside clinicians in early detection of the most severe aTAAD patients.