Abstract
A novel apparatus for non-invasive, in vivo evaluation of arterial mechanical properties was developed. A rigid airtight chamber with an ultrasound probe was attached to the forearm to manipulate transmural pressure (TP) of the radial artery by changing the pressure in the chamber. Pressure-diameter relationship of the radial artery was obtained by measuring the diameter with the probe while pressurizing and depressurizing the chamber. Pressure-diameter relationship of the radial artery could be obtained reproducibly over a wide range of TP. Contrary to intuition, the diameter decreased and increased when TP increased and decreased, respectively, in some TP ranges. This phenomenon disappeared when pressur-diameter relationship was obtained after taking alcohol, indicating that it was caused by the myogenic response of smooth muscle cells.This apparatus may be useful to measure not only pressure-diameter relationship but also contractility of smooth muscle cell.
