Fig. 1. Categories of Vascular Remodeling.

Remodeling can be hypertrophic, eutrophic, or hypotrophic. In hypertrophic remodeling, the medial cross-sectional area increases. In eutrophic remodeling, total medial cross-sectional area remains unchanged. In hypotrophic remodeling, cross-sectional area decreases. Remodeling that results in a reduction in luminal diameter with constant outside diameter is classified as inward remodeling (left panel). Remodeling that involves an increase in outside arterial diameter with a constant inside diameter is classified as outward remodeling (right panel). In eutrophic remodeling, both inside and outside diameters change. In the above panels, eutrophic remodeling is represented as a change in horizontal position with no vertical change. These combined structural changes profoundly influence the contractile characteristics of the individual smooth muscle cells within the medial layer.