P80: Identification of Radial Vascular Wall Abnormalities by Very-High Frequency Ultrasound in Patients with Fibromuscular Dysplasia: The Fuchsia Study

Abstract

Aim

This case-control study is aimed at identifying radial vascular wall abnormalities in patients with fibromuscular dysplasia (FMD).

Methods

High-frequency ultrasound scans of radial arteries were obtained by VevoMD (70 MHz probe, FUJIFILM, VisualSonics). Radial wall showed two echogenic interfaces: the 1^st (lumen-media) and the 2^nd (media-adventitia). Intima-media (IMT), adventitia (AT), and global thickness (IMAT) and wall cross-sectional area (WCSA) Measured. Vascular wall disarray was assessed calculating the root mean square error (RMSE) between 20 gray-level profiles crossing the two interfaces and the profile obtained averaging them, normalized for the maximum value of the corresponding mean profile (RMSE/mean).

Results

11 treated hypertensive female FMD patients and 8 healthy controls (C) were enrolled (age 52 ± 5 vs 45 ± 13years, p = 0.51; BMI 26 ± 3 vs 23 ± 3kg/mg, p = 0.12; mean BP 97 ± 7 vs 85 ± 10 mmHg, p = 0.01). Radial lumen was similar; IMT (0.166 ± 0.037 vs 0.128 ± 0.022mm, p = 0.03), AT (0.114 ± 0.029 vs 0.083 ± 0.019mm, p = 0.008) and IMAT (0.281 ± 0.042 vs 0.211 ± 0.027mm, p = 0.003) were higher in FMD. Wall/lumen ratio was similar and WCSA increased in FMD.

The maximum values of 1^st (121 ± 43 vs 157 ± 22, p = 0.09) and 2^nd interface 109 ± 44 vs133 ± 18, p = 0.09) tended to be lower, whereas RMSE/mean was higher in FMD (1^st 1.31 ± 0.24 vs 0.83 ± 0.32, p = 0.006; 2^nd 1.37 ± 0.38 vs 0.94 ± 0.32, p = 0.03). The difference was attenuated for the 1^st but not for the 2^nd interface when considering age and mean BP as covariates (p = 0.054 and p = 0.016 respectively).

Conclusions

The radial artery wall of hypertensive FMD patients shows increased thickness and its ultrastructure is characterized of loss of echogenicity and inhomogeneity of the two echogenic layers.