How Much Malperfusion Is Too Much in Acute Type A Aortic Dissections?

(1) Background: Malperfusion is a central limiting factor in the setting of acute Type A aortic dissections (AAAD). We sought to find preoperative metabolic acidosis thresholds that might influence decision-making in this setting. (2) Methods: We retrospectively reviewed consecutive patients operated on with AAAD between January 2002 and December 2017. We analyzed preoperative variables that might influence early and long-term outcomes, with particular emphasis on malperfusion markers. (3) Results: Our sample consisted of 153 patients, most of them male (69.2%), with a mean age of 55.89 ± 12.8 years. Malperfusion was present in 20.9% of cases: peripheric 25, renal 7, cerebral 4, and mesenteric 3. Cardiogenic shock was present in 18.9% of patients. Logistic regression revealed entry site (odds ratio (OR) = 2.83, p = 0.03), cardiogenic shock (OR = 3.30, p = 0.03), prebypass pH (OR = 0.93, p = 0.02) as independent risk factors for early death (<30 days). Receiver operating characteristic (ROC) analysis identified a prebypass pH of 7.25 as a cutpoint for an unfavourable early outcome. Patients whose prebypass pH was ≤7.25 had a 2.98 higher relative risk (65.7% vs. 22%, p < 0.001). Prebypass pH 7.25 (hazard ratio (HR) = 4.00, p < 0.01) and entry site (HR = 2.10, p = 0.04) were independent predictors of early phase survival (<30 days), while long-term survival (>30 days) was determined by age >65 years (HR = 3.12, p = 0.02). (4) Conclusions: Patients with a prebypass pH ≤ 7.25 have an unacceptably high early mortality after AAAD repair. Those patients might benefit from a two-stage approach.