CO-29: Carotid artery phenotyping using high-resolution radiofrequency – based echotracking system in patients with multifocal fibromuscular dysplasia: across-sectional study

Abstract

Background 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). Abstract CO-29 – Table FD EH HS Age, yrs 52 ± 9 52 ± 9 52 ± 9 Women, n (%) 43 (86%) 43 (86%) 42 (84%) Caucasian, n (%) 38 (76%) 38 (76%) 42 (84%) Office SBP, mmHg 125 ± 15 *** 121 ± 12 *** 113 ± 10 Antihypertensive drugs, n (range) 2 (1-4) 2 (1-4) 0 FD score, right CA 3.50 ± 1.43 ** 3.14 ± 1.16 2.84 ± 0.96 FD score, left CA 3.98 ± 1.57 ** 3.56 ± 1.43 ** 2.92 ± 1.07 Right CA triple signal, n (%) 11 (22%) ** 8 (16%) * 1 (2%) Left CA triple signal, n (%) 19 (38%) *** 15 (30%) ** 3 (6%) Right CA external diameter, mm 6.92 ± 0.57 7.10 ± 0.72 6.93 ± 0.66 Left CA external diameter, mm 6.89 ± 0.59 6.99 ± 0.63 6.81 ± 0.59 Right CA distensibility, μm 372 ± 105 381 ± 113 379 ± 116 Left CA distensibility, μm 347 ± 110 360 ± 117 360 ± 105 Right CA IMT, μm 610 ± 107 649 ± 134 601 ± 129 Left CA IMT, μm 655 ± 137 691 ± 171 637 ± 126 PWV, m/s 10.93 ± 2.07 ** 11.13 ± 2.02 *** 9.92 ± 1.70 * P ** P *** P Methods 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 semi-quantitative 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. FD and EH had significantly higher SBP than HS despite antihypertensive treatments. The FD score was significantly higher and the triple signal pattern was observed more frequently in both FD and EH (especially for the left CA) 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.