Conduit arterial stiffness is associated with impaired left ventricular subendocardial function.

Longitudinal function of the left ventricle is governed by the subendocardial myocardial fibres, whereas radial function is due mainly to contraction of circumferential fibres, localised in the subepicardial layer of the myocardium. In patients with diabetes or hypertension the subendocardial fibres are more likely to be affected by microvascular ischaemia. This can be caused by structural changes in the coronary vasculature that reduce myocardial perfusion such as arterial wall thickening, decreased capillary density, and periarteriolar fibrosis, and by haemodynamic changes such as increased wall stress, and the microcirculatory effects of endothelial dysfunction. Since tissue Doppler echocardiography can now assess longitudinal and radial myocardial velocities separately, we tested the further hypothesis that subendocardial dysfunction is related to conduit arterial stiffness.