Effect of olprinone, a phosphodiesterase III inhibitor, on arterial wall distensibility: Differentiation between aorta and common carotid artery

Although the effects of phosphodiesterase III (PDE III) inhibitors as vasorelaxants have been well documented, there are only few data on the wall response of different arteries. We evaluated the arteryspecific effect of olprinone (OP), one of the PDE III inhibitors, on the major branches of human arteries and peripheral circulation. In 14 healthy subjects (average age: 57.5 ± 21.2 years), systolic and diastolic diameters (Ds andDd, respectively) and the time velocity integral (VI) of flow velocity patterns were measured by M-mode and Doppler echocardiography in the carotid artery (CA), the ascending aorta (asAo), the abdominal aorta (abAo), and the left ventricular outflow tract. Blood pressure (BP) was simultaneously measured using a cuff sphygmomanometer. Measurements were taken before and 20min after a bolus injection of OP (0.2µg/kg). Distensibility (Ds −Dd), stiffness parameter β (ln(systolic BP/diastolic BP)/(Ds/Dd − 1)), cardiac output (CO: (Flow Area) × VI × HR at left ventricular outflow), selective flow volume (FV: (Flow Area) × VI × HR at CA or abAo), and vascular resistance (VR: mean BP/(CO or FV)) were then calculated. The distensibility increased significantly after OP administration (P = 0.0015), but that of the asAo or abAo did not change. Although there was a significant increase in CO (P = 0.001) and a significant decrease in systemic VR (P = 0.001) following OP administration, the FV and VR of both CA and abAo did not change significantly. The selectiveness of the effect of OP was demonstrated in terms of the CA wall distensibility. This was thought to be attributable to the differences in the structural components or the reactivity of smooth muscle cells to OP.