Noninvasive method for measuring local pulse wave velocity by dual pulse wave Doppler: in vitro and in vivo studies.

Yan Li,Yun-you Duan,Zhen Wang,Yong Yang,Tie-sheng Cao,Jie Liu,Li-jun Yuan

doi:10.1371/journal.pone.0120482

Abstract

ObjectivesTo evaluate the validity and reproducibility of a noninvasive dual pulse wave Doppler (DPWD) method, which involves simultaneous recording of flow velocity of two independent sample volumes with a measurable distance, for measuring the local arterial pulse wave velocity (PWV) through in vitro and in vivo studies.MethodsThe DPWD mode of Hitachi HI Vision Preirus ultrasound system with a 5–13MHz transducer was used. An in vitro model was designed to compare the PWV of a homogeneous rubber tubing with the local PWV of its middle part measured by DPWD method. In the in vivo study, local PWV of 45 hypertensive patients (25 male, 49.8±3.1 years) and 45 matched healthy subjects (25 male, 49.3±3.0 years) were investigated at the left common carotid artery (LCCA) by DPWD method.ResultsIn the in vitro study, the local PWV measured by DPWP method and the PWV of the homogeneous rubber tubing did not show statistical difference (5.16 ± 0.28 m/s vs 5.03 ± 0.15 m/s, p = 0.075). The coefficient of variation (CV) of the intra- and inter- measurements for local PWV were 3.46% and 4.96%, for the PWV of the homogeneous rubber tubing were 0.99% and 1.98%. In the in vivo study, a significantly higher local PWV of LCCA was found in the hypertensive patients as compared to that in healthy subjects (6.29±1.04m/s vs. 5.31±0.72m/s, P = 0.019). The CV of the intra- and inter- measurements in hypertensive patients were 2.22% and 3.94%, in healthy subjects were 2.07% and 4.14%.ConclusionsThis study demonstrated the feasibility of the noninvasive DPWD method to determine the local PWV, which was accurate and reproducible not only in vitro but also in vivo studies. This noninvasive echocardiographic method may be illuminating to clinical use.

Highlights

The arterial pulse wave velocity (PWV) is defined as the speed of pressure pulse wave generated by the contraction of the left ventricle propagating down the arterial tree
In the in vivo study, a significantly higher local PWV of left common carotid artery (LCCA) was found in the hypertensive patients as compared to that in healthy subjects (6.29±1.04m/s vs. 5.31± 0.72m/s, P = 0.019)
This study demonstrated the feasibility of the noninvasive dual pulse wave Doppler (DPWD) method to determine the local PWV, which was accurate and reproducible in vitro and in vivo studies

Summary

Introduction

The arterial pulse wave velocity (PWV) is defined as the speed of pressure pulse wave generated by the contraction of the left ventricle propagating down the arterial tree. The aortic PWV only provides the average PWV over a long segment composed of arteries with different mechanical characteristics and with a major source of inaccurate estimation due to the poor distance measurement on the body surface[10, 11] It may cause inaccuracy when local arteries are differently affected by aging and some diseases, for example, in early stage atherosclerosis [12]. Great emphasis has been placed on local or regional PWV in recent years [13, 14], since it may provide some diagnostic information of biomechanical properties for local artery wall, the mechanical characteristics of which vary along the arterial tree They are differently affected by aging and disease. Among the current noninvasive methods, none could be directly used to measure local PWV with accuracy and simplicity in clinical settings

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Conclusion