Understanding the Importance of the Small Artery Media-Lumen Ratio: Past and Present.

The media-lumen diameter ratio of small arteries is increased in hypertension, diabetes and obesity. It is likely that both shear stress on the endothelial cells, transmural pressure and smooth muscle cell tone are important for the altered vascular structure. However, the precise interaction and importance of these factors are incompletely understood. At the molecular level transglutaminases, metalloproteinases, integrins, NO and several other factors have been suggested to be important, but our understanding of how the many factors together control vascular structure is surprisingly limited. The media-lumen diameter ratio of the small arteries has prognostic value, which is independent of the classical risk factors for cardiovascular disease. Importantly this is also the case in patients treated pharmacologically for high blood pressure. It is therefore relevant to consider small artery structure as a potential target in relation to prevention of cardiovascular disease.