235 Pulse wave velocity assessment by external non-invasive devices and phase contrast magnetic resonance imaging in obese subjects

Abstract

Carotid-femoral pulse wave velocity (PWV) is considered as the “gold-standard” measurement of arterial stiffness. Obesity can render inaccurate PWV measurement by external non-invasive devices. This concerns both difficulties in obtaining pressure curves of good quality and technical difficulties in the measurement of distance. Phase-contrast magnetic resonance imaging (PCMRI), permits to determine aortic PWV in multiple aortic locations with intra arterial distance measurements and to assess aortic mechanical properties. The purpose of this study is to assess the reliability of external carotid-femoral PWV values measured by external well-validated devices, compared to PCMRI acquisitions of PWV and aortic mechanical properties in a population of obese subjects. PWV was measured with PulsePen and Complior II devices, in 32 volunteers (18 men), aged 46 to 65 years (mean: 55.7±5.1 ys), presenting an isolated abdominal obesity, waist circumference >102 cm for men and >88 cm for women and BMI from 27-35. These results were compared to the values of PWV and cross-sectional MRI thoracic aorta distensibility values. MRI PWV were correlated to PWV measured with Pulse Pen (r=0.47, p=0.005) and Complior (r=0.43, p=0.01). Also, cross-sectional thoracic aorta MRI distensibility was inversely correlated with Pulse Pen PWV (r= -0.41, p=0.02), and the same trend was found with Complior PWV (r= -0.33, p=0.06). The observed relationships were significant even after adjustment for age, gender, BMI and MAP. This is the first study to compare transcutaneous PWV measurements to PCMRI aortic elastic properties in obese subjects. Our results indicate that for BMI values up to 35 kg.m -2 , PWV measured externally with Complior or Pulse Pen reflects values obtained directly in the thoracic aorta with MRI.