Yoshinobu Nagasawa

MPS 13-04 EFFECTS OF VASODILATORS ON THE CARDIO-ANKLE VASCULAR INDEX (CAVI) IN ANESTHETIZED RABBITS

Objective: The arterial stiffness is known to be a good predictor of cardiovascular events in hypertensive patients. Cardio-ankle vascular index (CAVI) has been developed for measurement of vascular stiffness from the aorta to tibial artery, which is clinically utilized for assessing the progress of arteriosclerosis. Our recent study has demonstrated that the CAVI is decreased by a vasodilator affecting conduit and muscular arteries. In this study, we compared acute effects of various types of vasodilators on the CAVI in anesthetized rabbits. Design and Method: New Zealand White rabbits were anesthetized with halothane. For measurements of the heart-ankle pulse wave velocity (haPWV) and CAVI, the signals of electrocardiogram, phonocardiogram and blood pressure were fed to the VaSera system to be automatically calculated from the following well-established basic equation: CAVI = (2&rgr;/&Dgr;P) × ln(Ps/Pd) × haPWV2, where Ps is systolic blood pressure, Pd is diastolic blood pressure, haPWV is heart-ankle pulse wave velocity, &Dgr;P is Ps–Pd, &rgr; is blood density. Results: Intravenous administration of nitroglycerin or acetylcholine decreased the CAVI accompanied with hypotensive action and reduction of the haPWV. Intravenous administration of nifedipine, nicardipine or cilnidipine unaffected the CAVI, whereas each drug decreased the blood pressure and haPWV. On the other hand, intravenous administration of nicorandil increased the CAVI but decreased the blood pressure and haPWV. Conclusions: Acute effects on the CAVI were different among the vasodilators examined. Pharmacological properties like nitroglycerin and acetylcholine will be beneficial for the prevention of arteriosclerotic diseases of the large artery.