Recently an expert consensus group advised to measure carotid-femoral (cf) pulse wave velocity (PWV) on the right side of the body, using 80% of the distance between the carotid and femoral measurement site measured with a tape (80% rule). The present study investigated the real travelled cf path lengths at the left and right body side and compared the tape measure distance with the straight distance as obtained using an anthropometer.

Real travelled cf path lengths were measured with MRI in 98 healthy subjects (49 men, age 21–76 years). Path lengths from the aortic arch to the carotid (AA-CA) and femoral (AA-FA) sites were determined. The real travelled path length was calculated as (AA-FA)-(AA-CA). Straight distances between carotid and femoral sites were derived from the MRI images.

The real travelled cf path was slightly longer [11 mm (12), p<0.001] at the right side compared to the left. The proposed 80% rule overestimated real travelled cf path lengths with 0.5% at the right and 2.7% at the left side. Straight distance resembled more closely the real travelled distance (Right: 0.2 %, Left: 2.0 %), although not significantly different from tape measure (p=0.085).

The travelled cf path is slightly longer at the right than at the left body side. The present study supports the advice of the expert consensus group to preferentially measure cf-PWV at the right body side and suggests that the highest level of accuracy may be obtained using the straight distance, which supports the use of an anthropometer.