Chronic Type A aortic dissection: could surgical intervention be guided by molecular markers?

摘要

Aortic dissection, occurring following a separation of the layers constituting the complex vascular walls, leads to the formation of a ‘false’ lumen and disrupts the regulation of aortic wall homeostasis and function. This clinical condition still represents an important health problem and is associated with high mortality. Its natural history mandates surgical intervention when exceeding 55 mm in diameter and involving the ascending portion of the aorta (Type A), on the bases of an anatomical classification dated back to 1965. An intriguing question rising is whether a dissection that overcomes that critic acute phase has still the indication to surgical intervention. Molecular analysis of chronic dissected aortic walls could help in understanding how morphology and structure are affected and whether tissue homeostasis is re-established. Thus, pursued by this consideration, we made a histological and immunohistochemical characterization of a chronic Type A dissection, reporting three major findings: endothelial cells line the aortic primitive lumen, as well as the ‘false’ one; walls of primitive and ‘false’ lumina are comparable in thickness; vascular layers in the ‘false’ lumen are made up of terminally differentiated cells. This evidence obtained in a single specimen encourages a meditation on the compulsory indication for surgical intervention.