Wave intensity analysis (WIA): flow velocity lags influence calculated ascending aortic wave speed and reflected wave intensity during beta-adrenergic stimulation

The study of wave propagation at different points in the arterial circulation may provide useful information regarding ventriculoarterial interactions. We describe a number of hemodynamic parameters in the carotid, brachial, and radial arteries of normal subjects by using noninvasive techniques and wave-intensity analysis (WIA). Twenty-one normal adult subjects (14 men and 7 women, mean age 44 ± 6 yr) underwent applanation tonometry and pulsed-wave Doppler studies of the right common carotid, brachial, and radial arteries. After ensemble averaging of the pressure and flow-velocity data, local hydraulic work was determined and a pressure-flow velocity loop was used to determine local wave speed. WIA was then applied to determine the magnitude, timings, and energies of individual waves. At all sites, forward-traveling (S) and backward-traveling (R) compression waves were observed in early systole. In mid- and late systole, forward-traveling expansion waves (X and D) were also seen. Wave speed was significantly higher in the brachial (6.97 ± 0.58 m/s) and radial (6.78 ± 0.62 m/s) arteries compared with the carotid artery (5.40 ± 0.34 m/s; P < 0.05). S-wave energy was greatest in the brachial artery (993.5 ± 87.8 mJ/m2), but R-wave energy was greatest in the radial artery (176.9 ± 19.9 mJ/m2). X-wave energy was significantly higher in the brachial and radial arteries (176.4 ± 32.7 and 163.2 ± 30.5 mJ/m2, respectively) compared with the carotid artery (41.0 ± 9.4 mJ/m2; P < 0.001). WIA illustrates important differences in wave patterns between peripheral arteries and may provide a method for understanding ventriculo-arterial interactions in the time domain.

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Wave intensity analysis of left atrial mechanics and energetics in anesthetized dogs

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.00837.2006 ◽

2007 ◽

Vol 292 (3) ◽

pp. H1533-H1540 ◽

Cited By ~ 8

Author(s):

Tracy N. Hobson ◽

Jacqueline A. Flewitt ◽

Israel Belenkie ◽

John V. Tyberg

Keyword(s):

Mitral Valve ◽

Pulmonary Veins ◽

Left Ventricular ◽

Wave Intensity ◽

Intensity Analysis ◽

Wave Intensity Analysis ◽

Volume Loading ◽

Forward Movement ◽

Reflected Wave ◽

Left Atrial Mechanics

The left atrium (LA) acts as a booster pump during late diastole, generating the Doppler transmitral A wave and contributing incrementally to left ventricular (LV) filling. However, after volume loading and in certain disease states, LA contraction fills the LV less effectively, and retrograde flow (i.e., the Doppler Ar wave) into the pulmonary veins increases. The purpose of this study was to provide an energetic analysis of LA contraction to clarify the mechanisms responsible for changes in forward and backward flow. Wave intensity analysis was performed at the mitral valve and a pulmonary vein orifice. As operative LV stiffness increased with progressive volume loading, the reflection coefficient (i.e., energy of reflected wave/energy of incident wave) also increased. This reflected wave decelerated the forward movement of blood through the mitral valve and was transmitted through the LA, accelerating retrograde blood flow in the pulmonary veins. Although total LA work increased with volume loading, the forward hydraulic work decreased and backward hydraulic work increased. Thus wave reflection due to increased LV stiffness accounts for the decrease in the A wave and the increase in the Ar wave measured by Doppler.

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Wave speed in human coronary arteries is not influenced by microvascular vasodilation: implications for wave intensity analysis

Basic Research in Cardiology ◽

10.1007/s00395-014-0405-1 ◽

2014 ◽

Vol 109 (2) ◽

Cited By ~ 18

Author(s):

M. Cristina Rolandi ◽

Kalpa Silva ◽

Matthew Lumley ◽

Timothy P. E. Lockie ◽

Brian Clapp ◽

...

Keyword(s):

Coronary Arteries ◽

Wave Speed ◽

Wave Intensity ◽

Intensity Analysis ◽

Wave Intensity Analysis

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The role of wave speed in wave intensity analysis: a sensitivity study in coronary arterial data

Journal of Biomechanics ◽

10.1016/s0021-9290(06)85554-5 ◽

2006 ◽

Vol 39 ◽

pp. S614-S615

Author(s):

J. Aguado-Sierra ◽

J. Davies ◽

J. Mayet ◽

D. Francis ◽

A.D. Hughes ◽

...

Keyword(s):

Wave Speed ◽

Sensitivity Study ◽

Wave Intensity ◽

Intensity Analysis ◽

Wave Intensity Analysis

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Differences in cardiac microcirculatory wave patterns between the proximal left mainstem and proximal right coronary artery

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.00510.2008 ◽

2008 ◽

Vol 295 (3) ◽

pp. H1198-H1205 ◽

Cited By ~ 33

Author(s):

Nearchos Hadjiloizou ◽

Justin E. Davies ◽

Iqbal S. Malik ◽

Jazmin Aguado-Sierra ◽

Keith Willson ◽

...

Keyword(s):

Coronary Artery ◽

Flow Velocity ◽

Coronary Arteries ◽

Right Coronary Artery ◽

Coronary Flow ◽

Wave Intensity ◽

Intensity Analysis ◽

Wave Intensity Analysis ◽

Coronary Flow Velocity ◽

Proximal Right Coronary Artery

Despite having almost identical origins and similar perfusion pressures, the flow-velocity waveforms in the left and right coronary arteries are strikingly different. We hypothesized that pressure differences originating from the distal (microcirculatory) bed would account for the differences in the flow-velocity waveform. We used wave intensity analysis to separate and quantify proximal- and distal-originating pressures to study the differences in velocity waveforms. In 20 subjects with unobstructed coronary arteries, sensor-tipped intra-arterial wires were used to measure simultaneous pressure and Doppler velocity in the proximal left main stem (LMS) and proximal right coronary artery (RCA). Proximal- and distal-originating waves were separated using wave intensity analysis, and differences in waves were examined in relation to structural and anatomic differences between the two arteries. Diastolic flow velocity was lower in the RCA than in the LMS (35.1 ± 21.4 vs. 56.4 ± 32.5 cm/s, P < 0.002), and, consequently, the diastolic-to-systolic ratio of peak flow velocity in the RCA was significantly less than in the LMS (1.00 ± 0.32 vs. 1.79 ± 0.48, P < 0.001). This was due to a lower distal-originating suction wave (8.2 ± 6.6 × 103 vs. 16.0 ± 12.2 × 103 W·m−2·s−1, P < 0.01). The suction wave in the LMS correlated positively with left ventricular pressure ( r = 0.6, P < 0.01) and in the RCA with estimated right ventricular systolic pressure ( r = 0.7, P = 0.05) but not with the respective diameter in these arteries. In contrast to the LMS, where coronary flow velocity was predominantly diastolic, in the proximal RCA coronary flow velocity was similar in systole and diastole. This difference was due to a smaller distal-originating suction wave in the RCA, which can be explained by differences in elastance and pressure generated between right and left ventricles.

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Usefulness of Proximal Coronary Wave Speed for Wave Intensity Analysis in Diseased Coronary Vessels

Frontiers in Cardiovascular Medicine ◽

10.3389/fcvm.2020.00133 ◽

2020 ◽

Vol 7 ◽

Author(s):

Lorena Casadonte ◽

Jan Baan ◽

Jan J. Piek ◽

Maria Siebes

Keyword(s):

Wave Speed ◽

Coronary Vessels ◽

Wave Intensity ◽

Intensity Analysis ◽

Wave Intensity Analysis

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Wave Intensity Analysis of Left Ventricular Filling

Journal of Biomechanical Engineering ◽

10.1115/1.1992534 ◽

2005 ◽

Vol 127 (5) ◽

pp. 862-867 ◽

Cited By ~ 3

Author(s):

L. L. Lanoye ◽

J. A. Vierendeels ◽

P. Segers ◽

P. R. Verdonck

Keyword(s):

Left Ventricle ◽

Flow Velocity ◽

Three Dimensional ◽

Left Ventricular ◽

Elastic Tube ◽

Wave Intensity ◽

Time Interval ◽

Intensity Analysis ◽

Wave Intensity Analysis ◽

Intensity Pattern

Wave intensity analysis (WIA) is a powerful technique to study pressure and flow velocity waves in the time domain in vascular networks. The method is based on the analysis of energy transported by the wave through computation of the wave intensity dI=dPdU, where dP and dU denote pressure and flow velocity changes per time interval, respectively. In this study we propose an analytical modification to the WIA so that it can be used to study waves in conditions of time varying elastic properties, such as the left ventricle (LV) during diastole. The approach is first analytically elaborated for a one-dimensional elastic tube-model of the left ventricle with a time-dependent pressure-area relationship. Data obtained with a validated quasi-three dimensional axisymmetrical model of the left ventricle are employed to demonstrate this new approach. Along the base-apex axis close to the base wave intensity curves are obtained, both using the standard method and the newly proposed modified method. The main difference between the standard and modified wave intensity pattern occurs immediately after the opening of the mitral valve. Where the standard WIA shows a backward expansion wave, the modified analysis shows a forward compression wave. The proposed modification needs to be taken into account when studying left ventricular relaxation, as it affects the wave type.

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Non-invasive assessment of ventriculo-arterial coupling using aortic wave intensity analysis combining central blood pressure and phase-contrast cardiovascular magnetic resonance

European Heart Journal - Cardiovascular Imaging ◽

10.1093/ehjci/jez227 ◽

2019 ◽

Vol 21 (7) ◽

pp. 805-813 ◽

Cited By ~ 5

Author(s):

Anish N Bhuva ◽

A D’Silva ◽

C Torlasco ◽

N Nadarajan ◽

S Jones ◽

...

Keyword(s):

Blood Pressure ◽

Compression Wave ◽

Phase Contrast ◽

Wave Speed ◽

Wave Intensity ◽

Intensity Analysis ◽

Wave Intensity Analysis ◽

Reflection Index ◽

Non Invasive ◽

Local Wave

Abstract Background Wave intensity analysis (WIA) in the aorta offers important clinical and mechanistic insight into ventriculo-arterial coupling, but is difficult to measure non-invasively. We performed WIA by combining standard cardiovascular magnetic resonance (CMR) flow-velocity and non-invasive central blood pressure (cBP) waveforms. Methods and results Two hundred and six healthy volunteers (age range 21–73 years, 47% male) underwent sequential phase contrast CMR (Siemens Aera 1.5 T, 1.97 × 1.77 mm2, 9.2 ms temporal resolution) and supra-systolic oscillometric cBP measurement (200 Hz). Velocity (U) and central pressure (P) waveforms were aligned using the waveform foot, and local wave speed was calculated both from the PU-loop (c) and the sum of squares method (cSS). These were compared with CMR transit time derived aortic arch pulse wave velocity (PWVtt). Associations were examined using multivariable regression. The peak intensity of the initial compression wave, backward compression wave, and forward decompression wave were 69.5 ± 28, −6.6 ± 4.2, and 6.2 ± 2.5 × 104 W/m2/cycle2, respectively; reflection index was 0.10 ± 0.06. PWVtt correlated with c or cSS (r = 0.60 and 0.68, respectively, P < 0.01 for both). Increasing age decade and female sex were independently associated with decreased forward compression wave (−8.6 and −20.7 W/m2/cycle2, respectively, P < 0.01) and greater wave reflection index (0.02 and 0.03, respectively, P < 0.001). Conclusion This novel non-invasive technique permits straightforward measurement of wave intensity at scale. Local wave speed showed good agreement with PWVtt, and correlation was stronger using the cSS than the PU-loop. Ageing and female sex were associated with poorer ventriculo-arterial coupling in healthy individuals.

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WAVE SPEED IN THE HUMAN CORONARY ARTERY DOES NOT DECREASE WITH VASODILATION: EXTENDING THE LIMITS OF VALIDITY OF THE SINGLE–POINT TECHNIQUE FOR WAVE INTENSITY ANALYSIS

Journal of the American College of Cardiology ◽

10.1016/s0735-1097(13)61761-1 ◽

2013 ◽

Vol 61 (10) ◽

pp. E1761 ◽

Cited By ~ 1

Author(s):

Cristina Rolandi ◽

Kalpa de Silva ◽

Matt Lumley ◽

Tim Lockie ◽

Brian Clapp ◽

...

Keyword(s):

Coronary Artery ◽

Wave Speed ◽

Single Point ◽

Wave Intensity ◽

Intensity Analysis ◽

Wave Intensity Analysis ◽

Human Coronary Artery

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Feasibility of estimation of aortic wave intensity using non-invasive pressure recordings in the absence of flow velocity in man

10.1101/2020.01.22.20018457 ◽

2020 ◽

Author(s):

A.D. Hughes ◽

C. Park ◽

A. Ramakrishnan ◽

J. Mayet ◽

N. Chaturvedi ◽

...

Keyword(s):

Flow Velocity ◽

Ventricular Outflow Tract ◽

Left Ventricular ◽

Wave Intensity ◽

Intensity Analysis ◽

Wave Intensity Analysis ◽

S Wave ◽

Widespread Application ◽

Non Invasive ◽

Velocity Waveform

AbstractBackgroundWave intensity analysis provides valuable information on ventriculo-arterial function, hemodynamics and energy transfer in the arterial circulation. Widespread use of wave intensity analysis is limited by the need for concurrent measurement of pressure and flow waveforms. We describe a method that can estimate wave intensity patterns using only non-invasive pressure waveforms, and its reproducibility.MethodsRadial artery pressure and left ventricular outflow tract (LVOT) flow velocity waveforms were recorded in 12 participants in the Southall and Brent Revisited (SABRE) study. Pressure waveforms were analysed using custom-written software to derive the excess pressure (Pxs) which was compared with the LVOT flow velocity waveform, and used to calculate wave intensity. In a separate study, repeat measures of wave intensity and other wave and reservoir parameters were performed on 34 individuals who attended 2 clinic visits at an interval of approximately 1 month to assess reproducibility and reliability of the method.ResultsPxs waveforms were similar in shape to aortic flow velocity waveforms and the time of peak Pxs and maximum aortic velocity agreed closely (mean difference = 0.00 (limits of agreement −0.02, 0.02)s). Wave intensity patterns when scaled to peak LVOT velocity gave credible estimates of wave intensity similar to values reported previously in the literature. The method showed fair to good reproducibility for most parameters.ConclusionsThe Pxs is a surrogate of LVOT flow velocity allowing estimation of aortic wave intensity with acceptable reproducibility. This enables widespread application of wave intensity analysis to large studies.

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