The Strongest Risk Factor for Operative Mortality in Acute Type A Aortic Dissection is Acidosis: Validation of Risk Model

Multiple risk factors for operative mortality in the setting of acute type A aortic dissection (ATAAD) have been described. Recently, the combination of severe acidosis and malperfusion was found to significantly impact operative mortality following surgery for ATAAD and a treatment algorithm was proposed. The purpose of this study is to validate these findings in our institution. A retrospective chart review was performed for patients who underwent ATAAD repair between Feb 1997 and Jan 2018. Preoperative nadir pH, bicarbonate, base deficit, organ malperfusion, and other relevant parameters were collected. Multivariable logistic regression was performed to evaluate operative mortality. A total of 298 patients underwent ATAAD repair. The highest operative mortality (18/49; 37%) was noted in patients with severe acidosis (base deficit ≤ −10). There were 96 patients (32%) with malperfusion. In patients with abdominal malperfusion, this trend is even more pronounced. Multivariable logistic regression showed that severe acidosis is associated with higher operative mortality, odds ratio of 13.9 (P = 0.001). The presence of diabetes and advanced age were also associated with higher operative mortality. These findings validate the previously reported findings that severe acidosis is a strong predictor of operative mortality, and risk increases with associated organ malperfusion. This supports the suggestion that base deficit, which is easily performed at the bedside, should be used clinically to predict operative mortality and should be collected in aortic dissection databases.