A magnetic resonance perspective of the pulse wave transit time by the Arteriograph device and potential for improving aortic length estimation for central pulse wave velocity

BACKGROUND: Simple reproducible methods of measuring arterial stiffness, a powerful index of prognosis, are becoming available. AIM: To compare the pulse wave transit time (TT) and pulse wave velocity (PWV) between MRI and an arm cuff-based oscillometric method, the Arteriograph. MATERIALS AND METHODS: MRI phase-contrast data were acquired at the aortic arch and just above the aortic bifurcation in 49 men (age 53±6 years). Supine left-arm Arteriograph measurements were made after MRI using the surface sternal notch to symphysis pubis pathway length. RESULTS: MRI TT and PWV covered 86% of aortic root-bifurcation length omitting a mean 4.7 cm of proximal ascending aorta. Arteriograph TT (71±9 ms) was 6.6 ms [95% confidence interval (CI) 3.9-9.4] or 10% higher than MRI (64±10 ms). Arteriograph PWV (7.9±1.3 m/s) was 1.33 m/s (95% CI 0.95-1.70) higher than MRI (6.6±1.2 m/s), primarily because the surface aortic length was 70 mm (95% CI 59-81) longer than MRI. Arteriograph-MRI PWV difference decreased to 0.31 m/s (95% CI 0.01-0.61) when Arteriograph PWV was calculated using the MRI aortic path length and to 0.25 m/s (95% CI -0.05 to 0.55) after correcting for the aortic segments omitted in the MRI method. After similar TT corrections for MRI, the Arteriograph-MRI difference in TT reduced to 3.2 ms (95% CI 0.2-6). CONCLUSION: TT estimations by Arteriograph and MRI are close. More accurate length estimation from MRI-derived models improves Arteriograph PWV measurement.