Compliance and pulse wave velocity assessed by MRI detect early aortic impairment in young patients with mutation of the smooth muscle myosin heavy chain

Abstract

Purpose:To evaluate aortic elasticity with MRI on young asymptomatic individuals with mutation of the smooth muscle myosin heavy chain in whom aortic enlargement is not present. Materials and Methods:Aortic compliance, aortic distensibility, and pulse wave velocity (PWV) were semiautomatically measured from MRI in 8 asymptomatic subjects having a mutation of the MYH11 gene (Mϩ) and 21 nonmutated relatives (MϪ) of similar age, sex, and blood pressure characteristics.Results: Despite a similar aortic diameter in both groups, the aortic compliance and distensibility were significantly lower in Mϩ subjects compared with MϪ (0.84 Ϯ 0.33 versus 2.03 Ϯ 0.54 mm 2 /mmHg, 1.18 Ϯ 0.62 10 Ϫ3 versus 5.11 Ϯ 1.58 10 Ϫ3 mmHg Ϫ1 , respectively), and PWV was significantly higher (5.35 Ϯ 1.53 versus 3.60 Ϯ 0.64 m.s Ϫ1 ). A threshold aortic compliance value of 1.3 mm 2 /mmHg separated the two groups. The receiver operating characteristics curve analysis indicated an optimal threshold of 2.9 10 Ϫ3 mmHg Ϫ1 for aortic distensibility (sensitivity: 87.5%, specificity: 90%), and of 4.4 m.s Ϫ1 for PWV (sensitivity: 75%, specificity: 100%). Conclusion:Young asymptomatic adults with MYH11 mutation have an aortic compliance impairment which is not detectable by the sole measurement of the aortic size. Aortic compliance measurement might be part of routine examination in patients suspected of inherited aortic disease even with a normal aortic diameter.

Assessment of thoracic aortic elasticity: a preliminary study using electrocardiographically gated dual-source CT

“…Practically, the arterial blood volume is defined as the aortic cross-sectional area multiplied by the slice thickness. As the slice thickness is constant for the same study, the change in aortic cross-sectional area or diameter is the only parameter to consider in evaluation of elastic properties [8]. Therefore, cross-sectional area and diameter were used in the calculation of the elastic parameters such as relative diameter change (%Ao), distensibility (AoD, mm Hg −1 ), compliance (AoC, mm 2 /mm Hg) and stiffness index (AoSI).…”

“…Therefore, cross-sectional area and diameter were used in the calculation of the elastic parameters such as relative diameter change (%Ao), distensibility (AoD, mm Hg −1 ), compliance (AoC, mm 2 /mm Hg) and stiffness index (AoSI). The evaluated parameters were calculated as defined below and as previously published [8,12]:…”

“…Aortic elasticity is an important functional parameter of the aortic wall and decreases correlate with high blood pressure [3], future atherosclerotic diseases [4], coronary artery disease [5] and some arteriolar narrowing [6]. Aortic elasticity is widely accepted as an independent predictor of adverse cardiovascular outcomes at an early stage [7,8]. Therefore, the ability to evaluate aortic elasticity non-invasively early on is of great interest.…”

Measurement of aortic arch pulse wave velocity in cardiovascular MR: Comparison of transit time estimators and description of a new approach

“…Furthermore, tonometry uses body surface measurements to approximate artery length and does not take into account the often torturous route of the vessels. Cardiovascular MR (CMR) is increasingly used for measuring aortic arch PWV (arch-PWV) by using accurate aortic length and transit time between flow waves (16)(17)(18)(19)(20)(21)(22)(23)(24)(25). If robust aortic length measurement is an obvious strength of CMR thanks to many threedimensional (3D) imaging approaches available (26), transit time measurement remains a major challenge.…”

“…PC acquisitions are currently hampered by low temporal resolutions relative to tonometric methods. Consequently, different methods have been previously described to estimate the transit time using CMR (16,(18)(19)(20)(21)(22)(23)(24)(25)27), but there is to date no fully standardized method for its determination.…”