Carotid Artery Phenotyping Using High-Resolution Radiofrequency-Based Echotracking System In Patients With Multifocal Fibromuscular Dysplasia. A Cross-Sectional Study

Objective: Fibromuscular dysplasia (FD) is a rare idiopathic, segmental, non-atherosclerotic, non-inflammatory vascular disease, which occurs mostly in middle-aged patients and affects medium-sized arteries (renal and carotid arteries). We previously showed that renal FD is associated with supernumerary echo interfaces (triple signal pattern) detectable on echotracking tracings of the carotid artery (CA) compared to healthy subjects (HS), but we did not study patients with essential hypertension (EH). Design and method: In a cross sectional study, we compared the geometry and the mechanical properties of CA between 50 patients with multifocal FD of renal/carotid arteries, 50 patients with EH matched for age, sex, ethnicity and BP and 50 HS matched for age, sex and ethnicity. We used 1) a high-resolution radiofrequency–based echotracking system to perform a semiquantitative arterial phenotypic scoring and to detect additional interface at the level of the CA wall, and 2) Sphygmocor® to measure carotid-to-femoral pulse wave velocity (PWV). All measurements were performed blind to the diagnosis. Results: FD, EH and HS were well matched (52yrs, 85% women, 80%caucasian). SBP was higher in FD (125 ± 15 mmHg) and EH (121 ± 12 mmHg) than EH (113 ± 10 mmHg) despite antihypertensive treatments. The FD score was significantly higher and the triple signal pattern was observed more frequently in both FD and EH than in HS, with no difference between FD and EH. This was also the case for PWV. All other parameters (CA diameter, distensibility and intima-media thickness [IMT]) did not significantly differ between the 3 groups.Conclusions: In conclusion, even though the FD score is much higher and the prevalence of the triple signal is largely more frequent at the level of CA and PWV is higher in FD than in age, sex-, ethnicity-matched HS, this arterial phenotype is not specific for FD when compared to age-, sex- and BP-matched EH.