P.083 Comparison of Local Carotid and Aortic Stiffness Parameters in Mild Essential Hypertensive Patients

Abstract

Arterial stiffness (AS) can be evaluated by local pulse pressure (PP) and arterial diameter changes. We aimed to compare local AS, by an automatic edge detection system, with pulse wave velocity (PWV), the “gold standard” for AS.

In 27 patients (males 16, age 40 ± 7 years) with mild hypertension (HT) and 15 age and gender matched controls (NT), we measured carotid pulse pressure PP and central PWV by applanation tonometry (SphygmoCor^®). Diameter changes were measured by a contour tracking algorithm applied to B-mode longitudinal scans of common carotid artery. The algorithm is implemented on a stand-alone video processing system which acquires and analyzes video signal showing results in real-time. Distension (D) was calculated as systolic minus diastolic diameter. Stroke change in lumen area (δA) and lumen area (A) were evaluated from diameter and D values. The cross-sectional distensibility coefficient (DC = δA /(A*PP)) was converted (Bramwell-Hill equation) into a parameter (CS = (DC*ρ)^−1/2, ρ = blood density) with same measurement units of PWV.

HTshowed a significantly (p<0.0001) higher PWV (8.48 ± 1.45 m/s) than NT (5.44 ± 0.45 m/s). PP was similar in HT (60 ± 14 mmHg) and NT (58 ± 11). Carotid diameter was higher in HT (7.67 ± 0.67 mm) than NT (6.76 ± 0.40 mm). Carotid stiffness was higher in HT (CS = 7,35 ± 0.93 m/s) than in NT (CS = 5,76 ± 0.74 m/s; p<0.0001). PWV correlated with CS (r = 0.66;p<0.0001).

In conclusion, CS discriminates between HT and NT and is related with PWV. Automatic detection of carotid stiffness from ultrasound provide similar and-or complementary information to central PWV.