Hill's sign in aortic regurgitation: enhanced pressure wave transmission or artefact?

Hill's sign (an exaggerated difference in systolic arterial pressure between upper and lower limbs) is described in current textbooks of cardiology as an indicator of the severity of aortic insufficiency.

To evaluate the clinical value of Hill's sign in the assessment of aortic insufficiency. A further aim was to review arterial pressure transmission in health and disease to indicate whether aortic insufficiency might be associated with abnormalities of pressure wave transmission.

Observational study of central and peripheral arterial hemodynamics from five patients with severe aortic insufficiency compared with sphygmomanometrically recorded upper and lower limb pressures.

Diagnostic cardiac catheterization laboratory.

In five patients with proven severe aortic insufficiency, intra-arterial pressure measurements did not demonstrate any exaggerated difference in systolic pressure between either aortic and femoral or axillary and femoral arteries. Noninvasive sphygmomanometric pressures in the upper limb correlated well with axillary arterial recordings. However, lower limb noninvasive measurements gave systolic pressures well above the intraarterial recording, and in three patients the Korotkoff sounds over the popliteal artery could not be eliminated by high thigh cuff pressures.

A review of publications of arterial pressure transmission in health and disease does not indicate any physiological basis for Hill's sign. Therefore, on the basis of the present observations it is concluded that Hill's sign is an artefact of sphygmomanometric lower limb pressure measurement, has no physiological basis, and appears to be absent in some patients with severe aortic insufficiency. Hill's sign should, therefore, be removed from the list of diagnostic signs for aortic insufficiency.