Noninvasive assessment of carotid-femoral pulse wave velocity: the influence of body side and body contours

Background: Recently, an expert group advised to measure carotid-femoral (cf) pulse wave velocity (PWV) on the right side of the body, and to use a sliding caliper when tape measure distance cannot be obtained in a straight line. The present study investigates the evidence for this advice by comparing the real travelled cf path lengths (RTPLs) at both body sides and comparing the straight distance (as can be obtained with a sliding caliper) with the tape measure distance. Methods: RTPLs were measured with MRI in 98 individuals (49 men, age 21-76 years). Path lengths from the aortic arch to the carotid (AA-CA) and femoral (AA-FA) sites were determined. RTPL was calculated as (AA-FA) - (AA-CA) and compared between both sides. RTPLs were compared with 80% of the direct cf distance using a tape measure and the straight cf distance obtained from MRI images. Results: RTPL was slightly longer [11mm (12), P < 0.001] at the right side. The 80%-rule overestimated RTPLs with 0.5% at the right and 2.7% at the left side. Straight MRI distance tended (P = 0.09) to perform slightly better than tape measure distance. Conclusion: The travelled cf path is slightly longer at the right than at the left body side and the straight MRI distance tends to perform better than tape measure distance. The present study supports the advice of the expert consensus group to measure cf-PWV at the right body side using a sliding caliper when tape measure distance cannot be obtained in a straight line.