Confined Acute Type A Aortic Dissection is Characterized by Atherosclerosis

Abstract

Objectives: Ascending aortic atherosclerosis and degeneration may influence surgical management and outcome following surgery for acute Type A aortic dissection (ATAAD). The aim of this study was to evaluate the association between histologically confirmed ascending aortic atherosclerosis and postoperative outcome in patients undergoing surgery for ATAAD. Methods: We retrospectively evaluated 104 patients without connective tissue disorders undergoing surgery for ATAAD at Tampere University Hospital between January 2005 and November 2019. Resected ascending aortic specimens were processed for histopathology, assessing atherosclerosis, medial degeneration, and inflammation. Patients were divided into groups based on the presence (n = 58) or absence (n = 46) of histologically confirmed atherosclerosis and compared over a median follow-up of 5.9 years (interquartile range [IQR]: 0.9–8.0). Results: The median age for all patients was 67.0 years (IQR: 57.0–73.0). Patients with atherosclerosis had more frequent primary intimal tears in the aortic root (62.1% vs. 39.1%, p = 0.020), but less frequent limb malperfusion (5.2% vs. 32.6%, p < 0.001), and DeBakey I dissections (53.4% vs. 76.1%, p = 0.017) as compared to those without atherosclerosis, respectively. The presence and severity of medial degeneration were significantly greater in patients with atherosclerosis (98.3% vs. 87.0%, p = 0.042; mean severity score 2.2 vs. 1.8, p = 0.044). Postoperatively, the incidence of stroke was significantly higher in the atherosclerosis group (41.4% vs. 21.7%, p = 0.034), but the rate of aortic reintervention was significantly lower (5.2% vs. 19.6%, p = 0.023). Survival did not differ significantly between the groups (log-rank p = 0.683), and limb malperfusion was the only strong independent risk factor for all-cause mortality according to multivariable Cox regression analysis. Conclusion: Ascending aortic atherosclerosis including severe medial degeneration during ATAAD is associated with distinct clinical features such as the presence of proximal aortic root tear. Instead, limb malperfusion, DeBakey I classification, and presence of ascending aortic tear suggest an ascending aorta without atherosclerosis, often associated with increased risk of aortic reinterventions after surgery for ATAAD.