The profound impact of combined severe acidosis and malperfusion on operative mortality in the surgical treatment of type A aortic dissection

Objectives: Surgery for type A aortic dissection is associated with a high operative mortality, and a variety of predictive risk factors have been reported. We hypothesized that a combination of risk factors associated with organ malperfusion and severe acidosis that are not currently documented in databases would be associated with a level of extreme operative risk that would warrant the consideration of treatment paradigms other than immediate ascending aortic surgery. Methods: Charts of patients undergoing repair of acute type A aortic dissection between January 1, 1996, and May 1, 2016, were queried for preoperative malperfusion, preoperative base deficit, pH, bicarbonate, cardiopulmonary resuscitation, severe aortic insufficiency, redo status, and preoperative intubation. Multivariable logistic analyses were considered to evaluate interested variables and operative mortality. Results: Between January 1, 1996, and May 1, 2016, 282 patients underwent surgical repair of type A aortic dissection. A total of 66 patients had a calculated base deficit -5 or greater. Eleven of 12 patients (92%) with severe acidosis (base deficit >= -10) with malperfusion had operative mortality. No patient with severe acidosis with abdominal malperfusion survived. Multivariable analyses identified base deficit, intubation, congestive heart failure, dyslipidemia/statin use, and renal failure as predictors of operative death. The most significant predictor was base deficit -10 or greater (odds ratio, 9.602; 95% confidence interval, 2.649-34.799). Conclusions: The combination of severe acidosis (base deficit >= -10) with abdominal malperfusion was uniformly fatal. Further research is needed to determine whether the identification of extreme risk warrants consideration of alternate treatment options to address the cause of severe acidosis before ascending aortic procedures.