INFLUENCE OF APPLIED BRACHIAL RECORDING FORCES ON PULSE-WAVE VELOCITYAND TRANSMISSION IN THE BRACHIO-RADIAL ARTERIAL SEGMENT

Arterial stiffness in hypertension and heart failure may increase afte rload on the left ventricle. Pulse wave velocity and transmission rati o measurements are noninvasive methods to assess arterial stiffness. S ince noninvasive pressure pulse recording requires sufficient applied force to distort the vessel wall, we hypothesized that the pulse wave velocity, transmission ratios, and distal pulse amplitudes and contour s may be altered by the recording technique. Brachial and radial arter ial pressure pulses were recorded simultaneously using a piezoelectric pulse transducer in 14 young, normal, male subjects using 10 brachial artery recording forces (0.35-3.58N, approximate to 0.36N increments) applied in a random order and a constant radial force (2.35N). Pulses were Fourier analyzed. One subject was excluded from analysis because of improper transducer positioning over the brachial artery. In 8 sub jects, no significant changes occurred in any variable over all brachi al recording forces. In the remaining 5 subjects, the measured variabl es remained constant until brachial artery recording forces exceeded 2 .42 +/- 0.03N. The pulse wave velocity (p < 0.04), transmission ratios (harmonics 2-5,p < 0.0001), radial pulse amplitude (p < 0.0003), and relative powers (harmonics 2-5, p < 0.02) then decreased. In these sub jects, brachial artery depths were less than the other subjects (5.9 /- 0.4 vs. 7.7 +/- 0.4 mm, p < 0.05). The brachial and radial artery r ecording forces normally used during clinical measurements by 2 invest igators were 1.43 +/- 0.01N (95% confidence intervals (CI) = 1.23N, 1. 62N) and 1.88 +/- 0.11N (95% CI= 1.65N, 2.10N), respectively. Therefor e, at forces normally used by clinical investigators, the pulse wave v elocity, harmonic transmission ratios, and pulse amplitudes and contou rs obtained at the brachial and radial artery are not significantly in fluenced by forces applied at the brachial artery. However, these vari ables may be decreased in subjects with more superficial arteries when higher recording forces are used.