Surviving the remodel: the impact of hypertension during pregnancy.

Abstract

Diverse structural and functional changes occur within blood vessels during hypertension. In relation to vascular structure, hypertension is generally associated with hypertrophy (increased cross-sectional area of the vessel wall) in aorta and other large arteries but inward remodeling (with or without increases in the cross-sectional area) in smaller resistance vessels. Inward vascular remodeling, which represents a rearrangement of the vessel wall around a smaller lumen (Figure), has been described in models of hypertension in brain1 and other vascular beds.2,3 Similar changes occur in humans with hypertension, where inward remodeling is emerging as a potential risk factor for cardiovascular events.4 Figure. Schematic of structural changes in blood vessels shown in cross-section. The starting point is the vessel under control (normotensive) conditions shown on top. During chronic hypertension, vessels exhibit inward remodeling, such that the inner and outer diameter are reduced (lower right). This change increases vascular resistance, including minimal vascular resistance, and reduces transmission of pressure to the microcirculation. With hypertension during pregnancy, there is reversal (regression) of inward remodeling such that the vessel diameter returns largely to normal (bottom left). As a consequence of this outward remodeling, vascular resistance is reduced, and increases in microvascular pressure and permeability will be greater during acute hypertension or seizures. See text for additional details. Although the term “vascular remodeling” is sometimes used rather imprecisely in studies of blood vessels, experts in the field consider inward vascular remodeling to reflect reductions in vessel diameter that are present over a range of intravascular pressures and …