What question did this study set out to answer?

This research aims to compare different methods of measuring carotid-femoral pulse wave velocity (PWV) under various conditions.

January 11, 2005

Evaluation of Carotid-Femoral Pulse Wave Velocity

Q: What is the clinical evidence from this study?

Study design: Other. Intervention: Foot-to-foot method (SphygmoCor system) vs. Maximum slope method (Complior system). Primary outcome: Carotid-femoral pulse wave velocity (PWV) (MD 1.7).

Key Result

The foot-to-foot method for measuring carotid-femoral pulse wave velocity yielded values 1.7 m/s higher than the maximum slope method, though both detected PWV increases with heart rate.

Key Points

This research aims to compare different methods of measuring carotid-femoral pulse wave velocity (PWV) under various conditions.
Measured PWV at rest, during beta-adrenergic stimulation, and pacing-induced tachycardia.
Utilized SphygmoCor and Complior systems for PWV measurement.
Sample size included 43 at rest, 10 under isoprotenerol, and 11 with pacing.
At rest, PWV using the SphygmoCor system was 1.7 m/s greater than Complior (mean value 12 m/s, P<0.001).
Isoprotenerol increased PWV by 0.7 m/s (SphygmoCor) and 0.9 m/s (Complior), confirming heart rate effects (P<0.001).
Pacing led to a notable increase in PWV as well, with SphygmoCor recording 2.1 m/s and Complior recording 1.1 m/s (P<0.001).

PICO

Population

43 subjects evaluated at rest, with subsets undergoing isoprotenerol infusion (n=10) or pacing (n=11) to compare pulse wave velocity measurement methods.

Exposure / Comparator

Foot-to-foot method (SphygmoCor system) vs Maximum slope method (Complior system)

Primary Outcome

Carotid-femoral pulse wave velocity (PWV) — MD 1.7

Main Result

Mean Difference: 1.7

Abstract

Carotid-femoral pulse wave velocity (PWV), a measure of arterial stiffness, is determined from the time taken for the arterial pulse to propagate from the carotid to the femoral artery. Propagation time is measured variously from the foot of the waveform or point of maximum upslope. We investigated whether these methods give comparable values of PWV at rest, during beta-adrenergic stimulation, and pacing-induced tachycardia. In subjects at rest (n=43), values obtained using the foot-to-foot method (SphygmoCor system) were 1.7+/-0.75 m/s (mean+/-SD) greater than those obtained using the maximum slope (Complior system) at a mean value of 12 m/s. Isoprotenerol (0.5 to 1.5 microg/min; n=10), and pacing (in subjects with permanent pacemakers; n=11) increased heart rate but had differential effects on systolic blood pressure and pulse pressure. The increase in heart rate produced by isoprotenerol (18+/-3 bpm) and pacing (40 bpm) was associated with an increase in PWV measured using both systems (increases of 0.7+/-0.2 m/s and 0.9+/-0.2 m/s for SphygmoCor and Complior, respectively, during isoprotenerol and increases of 2.1+/-0.5 m/s and 1.1+/-0.2 m/s for SphygmoCor and Complior, respectively, during pacing, each P<0.001). Reanalysis of waveforms recorded from the Complior system using the foot-to-foot method produced similar values of PWV to those obtained with the SphygmoCor, confirming that the difference between these systems was attributable to the timing algorithm rather than other aspects of signal acquisition. Carotid-femoral PWV is critically dependent on the method used to determine propagation time, but this does not account for variation of PWV with heart rate.