Pulse Wave Velocity Assessment by External Noninvasive Devices and Phase-Contrast Magnetic Resonance Imaging in the Obese

Abstract

Abstract-Carotid-femoral pulse wave velocity (PWV) is considered the gold-standard measurement of arterial stiffness.Obesity, however, can render inaccurate the measurement of PWV by external noninvasive devices. Phase-contrast MRI allows the determination of aortic PWV in multiple aortic locations with intra-arterial distance measurements, as well as the assessment of aortic mechanical properties. Key Words: arterial stiffness Ⅲ pulse wave velocity Ⅲ obesity Ⅲ MRI Ⅲ aortic distensibility A rterial stiffness assessed by pulse wave velocity (PWV) measurement is now well accepted as an independent predictor of cardiovascular mortality and morbidity. 1 Rapid and reproducible external noninvasive methods are the gold standard for measuring PWV by recording the pressure waves at respective carotid and femoral sites. 2 Several recent studies have indicated an effect of obesity on arterial stiffness, especially when associated with metabolic disorders. [3][4][5] Therefore, measurements of PWV in overweight and obese subjects may be of major interest in assessing cardiovascular risk. However, obesity is a well known factor of technical operator bias when assessing PWV. 2,6 This concerns both difficulties in obtaining pressure curves of good quality and technical difficulties in measuring distance. In this context, PWV assessment is questionable in overweight and obese subjects [2][3][4]6,7 ; therefore, a comparison between external PWV-recording transcutaneous devices and internal noninvasive methods, eg, phase-contrast MRI, could prove valuable, while also providing morphological information. 8 -10 In fact, the acquisition of cross-sectional MRI aortic vascular structural indices, provided by combined high spatial and temporal resolutions, should not be affected by either body composition or imaging plane.The current study was designed to assess the relationship between PWV values obtained with 2 well-validated transcutaneous devices (Complior II and PulsePen) and MRI acquisition of PWV along with aortic cross-sectional mechanical properties estimated by aortic distensibility and compliance, aortic elastic modulus, and stiffness index in a population presenting isolated abdominal obesity considered to reflect a high disease risk and defined by a waist circumference Ͼ102 cm for men and Ͼ88 cm for women in overweight and obese patients (body mass index from 27 to 35 kg m Ϫ2 ). Methods Subject SelectionEighteen male and 14 female subjects presenting with isolated abdominal obesity were prospectively recruited by local press

Determination of Travel Distance for Noninvasive Measurement of Pulse Wave Velocity: Case Closed?

“…Precise determination of the distance traveled by the pulse wave is easily feasible with the latter 2 methods but has been a matter of debate for noninvasive techniques for the last few years. 1 Therefore, we are pleased to find that absolute values for aortic pulse wave velocity, measured using MRI, were in good agreement with absolute cfPWV values, obtained by state-of-the-art noninvasive devices, in the study by Joly et al 2 Of note, pulse wave travel distance for noninvasive cfPWV assessment was measured by subtracting the distance from the carotid location to the suprasternal notch from the distance between this notch and the femoral site of measurement. This is in agreement with our recent invasive study 3 in a similar age group (55.7 versus 60.3 years), where the same approach to travel distance estimation provided the closest similarity with invasive aortic pulse wave velocity, as measured during catheter withdrawal from the ascending aorta to the bifurcation.…”

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

“…A study by Lalande et al (21) presented a method for Dt estimation based on a least squares minimization considering the entire shape of the velocity curves, and reported a mean value of arch-PWV of 3.6 6 0.64 m/s (age, 25 6 5 years; n ¼ 21). Furthermore, this wave-to-wave method is used in dedicated software (Giuseppe Lio, DiaTecne, Milan, Italy) (36). A recent study (28), used an upslopeto-upslope method, which estimated Dt by minimizing the area between systolic upslope portions of velocity curves by temporal shifts of 1 ms.…”

Changes in Subendocardial Viability Ratio With Acute High-Altitude Exposure and Protective Role of Acetazolamide

“…This is a validated, easy-to-use, and high-fidelity applanation tonometer, described in detail in previous articles 17,18 and in the online-only Data Supplement. Pulse pressure waveforms were recorded with patients resting supine and in temperature-controlled environment in accordance with consensus recommendations.…”