The acute effect of hyperglycaemia on vessel wall properties

Arterial distensibility is a marker of functional and structural vessel wall properties. A decreased distensibility is an important risk factor for cardiovascular disease. In insulin-dependent diabetes mellitus of short duration, arterial stiffness has been reported to be increased, decreased or the same as in healthy control subjects. The influence of acute hyperglycaemia on arterial stiffness is unclear and might be one of the factors responsible for the divergent results which have been observed. We investigated arterial distensibility locally in the carotid artery during hyper- and normoglycaemia using a glucose clamp technique. Eleven healthy normotensive men underwent both a hyperglycaemic and a euglycaemic clamp on separate days. Before and after 2 h of clamping, arterial diameter (D) and change in arterial diameter during the heart cycle (dD) were measured with a non-invasive vessel wall movement detector system. Blood pressure (BP), pulse pressure (dP) and heart rate (HR) were recorded with a semi-automated device. Distensibility coefficients (DC), reflecting the intrinsic vascular wall elasticity, and compliance coefficients (CC), reflecting the buffering capacity of the vessel, were calculated from D, dD and dP. (DC = 2*dD/ D*dP, CC = pi*dD*D/2*dP). There were no significant differences between the hyperglycaemic and the euglycaemic clamp for D, DC and CC. These results suggest that an acute systemic hyperglycaemia is not responsible for changes in diameter, distensibility and compliance of the carotid artery.