Redefining the histopathologic profile of acute aortic syndromes: clinical and prognostic implications

Objectives: The study objectives were to describe the aortic histopathologic substrates in patients with type A surgically treated acute aortic syndromes, to provide clinico-pathological correlations, and to identify the possible prognostic role of histology. Methods: We assessed the aortic wall degenerative or inflammatory alterations of 158 patients according to the histopathologic consensus documents. Moreover, we correlated these histologic patterns with the patients' clinical data and long-term follow-up for mortality, major aorta-related events, and nonaorta-related events (including cardiovascular ones). Results: We identified 2 histopathologic patterns: 122 patients (77%) with degenerative alterations and 36 patients (23%) with mixed degenerative-atherosclerotic lesions. Patients with mixed alterations were older (mean 69.6 ± 8.7 years vs 62.2 ± 12.4 years, P = .001) and more hypercholesterolemic (33.3% vs 13.9%, P = .017). The degenerative subgroup showed more intralamellar-mucoid extracellular matrix accumulation (86% vs 66.7%, P = .017) and a lower prevalence of translamellar collagen increase (9.8% vs 50%, P < .001). Patients with mixed degenerative-atherosclerotic abnormalities more frequently had long-term nonaorta-related events compared with those with degenerative abnormalities alone (P = .046); no differences were found between the groups with respect to mortality, major aorta-related events, and cardiovascular nonaorta-related events. Conclusions: Although degenerative lesions of the medial layer were present in all specimens, substantial atherosclerosis coexisted in approximately one quarter of cases. Patients with mixed degenerative-atherosclerotic abnormalities had a coherent clinical risk profile, a clinical presentation frequently mimicking acute coronary syndrome, and a higher incidence of nonaorta-related events during follow-up. Histopathologic characterization may improve the long-term prognostic stratification of patients after surgical treatment. © 2018 The American Association for Thoracic Surgery