Non-invasive monitoring of the dynamic compliance in the carotid artery

A device has been developed to monitor non-invasively, continuously and simultaneously both the intravascular pressure and the vessel diameter of the carotid artery. The intravascular pressure is obtained by using the applanation method. The pressure sensor utilizes the principle that the extravascular pressure necessary to flatten the vessel wall is equal to the intravascular pressure. The vessel diameter is determined by employing the four-electrode bioimpedance method. This approach is based on the principle that the conductivity of blood is much higher than for the surrounding tissue including the vessel wall. The device has been successfully applied in 12 healthy persons of different age and gender, and in a patient with strong atherosclerosis during ballon dilatation of the carotid artery. The results can be utilized for estimating the visco-elastic behaviour of the vessel wall. Pathological changes of the vessel wall structure can be detected