Acute Aortic Disease.. - Index of

230 Sanz et al.
will summarize current recommendations for the medical management in subjects
with acute aortic dissection, with special emphasis on drug therapy.
AORTIC WALL STRUCTURE
The aortic wall is composed of three layers: the intima, the media, and the adventitia
(Fig. 1). The intima consists of a thin monolayer of endothelial cells resting
on a basal membrane and a variable amount of subendothelial space that contains
fibroblasts and connective tissue. The contribution of the endothelial layer to
modulation of wall tension is considered negligible (4).
The media is constituted by cellular elements (mostly smooth muscle cells)
and extracellular matrix that contains a variety of structural proteins, of which collagen
and elastin are the most important. Elastin forms fibers that organize in circumferential
layers with interspersed cells and collagen, a structure known as a
Figure 1 Transverse section of the wall of a large elastic artery demonstrating the welldeveloped
tunica media containing elastic lamellae (pararosaniline–toluidine blue stain;
medium magnification). Source: From Ref. 97.