Hemodynamics of the radial artery, the site of traditional pulse diagnosis

Abstract

Background Pulse diagnosis is a method used in traditional medicine around the world, and is mainly performed at the radial artery. However, there are few reports on radial artery hemodynamics because it is difficult to measure the blood flow volume in a thin vessel like this artery. Methods Thirty-three healthy volunteers (mean age: 34.2±7.6 years; 26 men and 7 women) were enrolled. We measured the hemodynamics of the right radial artery for approximately 50 s after 10 min of rest in the supine position. Hemodynamics was assessed with a Prosound α10 ® ultrasound system (Aloka Co., Ltd., Tokyo, Japan). This system had a high-resolution linear array transducer (13 MHz) and computer-assisted analytical software (e-Tracking system ® , Aloka Co., Ltd.) that allowed automatic detection of the vessel edge, as well as continuous measurement of the vessel diameter and blood flow volume. Analysis The mean end-systolic radial artery diameter, mean end-diastolic diameter, mean blood velocity, and mean blood flow volume were calculated each second after smoothing the per-beat values of end-systolic diameter, end-diastolic diameter, mean blood velocity, and mean blood flow volume with MATLAB (Ver.2007b, MathWorks).Then, fast Fourier transformation (FFT) was performed with MATLAB to obtain the power spectra of these indices. Results In all subjects, FFT-end systolic diameter, FFT-end diastolic diameter, FFT-flow velocity, and FFT-flow volume showed peaks of the power spectrum at a low frequency (LF) and a high frequency (HF).The LF and HF peaks of FFT-flow volume were significantly different from the LF and HF peaks of FFT-flow velocity ( p =0.011, p =0.041, respectively).However, the LF and HF peaks of FFT-flow volume were not significantly different from the LF and HF peaks of FFT-end systolic diameter and FFT-end diastolic diameter. Conclusion Two peaks in the power spectrum of flow volume were observed, indicating the existence of fluctuation of radial artery blood flow volume. It is suggested that fluctuation of the blood flow volume is influenced by fluctuation of the end-systolic diameter and end-diastolic diameter.