Noninvasive pulmonary artery wave intensity analysis in pulmonary hypertension

Quail, Michael A.; Knight, Delvin R.; Steeden, Jennifer A.; Taelman, Liesbeth; Moledina, Shahin; Taylor, Andrew M.; Segers, Patrick; Coghlan, J. Gerry; Muthurangu, Vivek

doi:10.1152/ajpheart.00480.2014

Cited by 60 publications

(94 citation statements)

References 37 publications

(46 reference statements)

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“…We elected to use changes in proximal aortic distension to derive changes in central aortic pressure over the cardiac cycle as this had previously been validated using CMR [8]. This assumes linearity between pressure and area [30]. Compared to vessel diameter changes, which was the technique employed for ultrasound-derived wave intensity in the carotid arteries, measurement of cross sectional area changes offered several advantages.…”

Section: Discussionmentioning

confidence: 99%

Feasibility of cardiovascular magnetic resonance derived coronary wave intensity analysis

Raphael

Keegan

Parker

et al. 2016

Journal of Cardiovascular Magnetic Resonance

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BackgroundWave intensity analysis (WIA) of the coronary arteries allows description of the predominant mechanisms influencing coronary flow over the cardiac cycle. The data are traditionally derived from pressure and velocity changes measured invasively in the coronary artery. Cardiovascular magnetic resonance (CMR) allows measurement of coronary velocities using phase velocity mapping and derivation of central aortic pressure from aortic distension. We assessed the feasibility of WIA of the coronary arteries using CMR and compared this to invasive data.MethodsCMR scans were undertaken in a serial cohort of patients who had undergone invasive WIA. Velocity maps were acquired in the proximal left anterior descending and proximal right coronary artery using a retrospectively-gated breath-hold spiral phase velocity mapping sequence with high temporal resolution (19 ms). A breath-hold segmented gradient echo sequence was used to acquire through-plane cross sectional area changes in the proximal ascending aorta which were used as a surrogate of an aortic pressure waveform after calibration with brachial blood pressure measured with a sphygmomanometer. CMR-derived aortic pressures and CMR-measured velocities were used to derive wave intensity. The CMR-derived wave intensities were compared to invasive data in 12 coronary arteries (8 left, 4 right). Waves were presented as absolute values and as a % of total wave intensity. Intra-study reproducibility of invasive and non-invasive WIA was assessed using Bland-Altman analysis and the intraclass correlation coefficient (ICC).ResultsThe combination of the CMR-derived pressure and velocity data produced the expected pattern of forward and backward compression and expansion waves. The intra-study reproducibility of the CMR derived wave intensities as a % of the total wave intensity (mean ± standard deviation of differences) was 0.0 ± 6.8%, ICC = 0.91. Intra-study reproducibility for the corresponding invasive data was 0.0 ± 4.4%, ICC = 0.96. The invasive and CMR studies showed reasonable correlation (r = 0.73) with a mean difference of 0.0 ± 11.5%.ConclusionThis proof of concept study demonstrated that CMR may be used to perform coronary WIA non-invasively with reasonable reproducibility compared to invasive WIA. The technique potentially allows WIA to be performed in a wider range of patients and pathologies than those who can be studied invasively.Electronic supplementary materialThe online version of this article (doi:10.1186/s12968-016-0312-8) contains supplementary material, which is available to authorized users.

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Section: Discussionmentioning

confidence: 99%

Feasibility of cardiovascular magnetic resonance derived coronary wave intensity analysis

Raphael

Keegan

Parker

et al. 2016

Journal of Cardiovascular Magnetic Resonance

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“…However, PWVs in the main, proximal left and proximal right pulmonary arteries were again approximately doubled in patients with PH compared with age-matched healthy volunteers. By extending the analysis of the relationship between the flow and cross-sectional area, Quail et al 63 were moreover able to demonstrate the altered wave reflection behaviour present in PH. 53,58 …”

Section: Advanced Pc Parameters Of the Pulmonary Arterial Vasculaturementioning

confidence: 96%

“…Authors reported shortened acceleration times (ATs) (time interval from the beginning of the anterograde flow in systole to peak systolic flow) and reduced passing blood volumes during that time (AccV, acceleration volume) in PH, reflecting increased PVR and the impairment of the right ventricular ejection function. 27,62,63 Mousseaux et al 62 documented a strong correlation between PVR and the quotient of maximum change in flow rate during ejection by AccV ( r = 0.89). Moreover, Sugimoto et al 64 found that the maximum change in flow rate during ejection, when normalized to the body surface area, was significantly higher in children with PH than in children without PH and correlated strongly with pulmonary-to-systemic blood pressure ratio in children with PH ( r = 0.90); the parameters AT, ET, AT/ET, AccV and v peak revealed no significant differences between the PH and non-PH groups.…”

Section: Standard Pc Parameters Of the Main Pulmonary Artery In Phmentioning

confidence: 98%

“…Quail et al 63 derived substantially lower PWVs in the pulmonary artery by the QA approach, which possibly might be explained by differences in the time resolution of the employed PC imaging protocols or duration of the early systolic phase used for fitting. However, PWVs in the main, proximal left and proximal right pulmonary arteries were again approximately doubled in patients with PH compared with age-matched healthy volunteers.…”

Section: Advanced Pc Parameters Of the Pulmonary Arterial Vasculaturementioning

confidence: 99%

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MR phase-contrast imaging in pulmonary hypertension

Reiter

Fuchsjäger

2016

BJR

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Pulmonary hypertension (PH) is a life-threatening, multifactorial pathophysiological haemodynamic condition, diagnosed when the mean pulmonary arterial pressure equals or exceeds 25 mmHg at rest during right heart catheterization. Cardiac MRI, in general, and MR phase-contrast (PC) imaging, in particular, have emerged as potential techniques for the standardized assessment of cardiovascular function, morphology and haemodynamics in PH. Allowing the quantification and characterization of macroscopic cardiovascular blood flow, MR PC imaging offers non-invasive evaluation of haemodynamic alterations associated with PH. Techniques used to study the PH include both the routine two-dimensional (2D) approach measuring predominant velocities through an acquisition plane and the rapidly evolving four-dimensional (4D) PC imaging, which enables the assessment of the complete time-resolved, three-directional blood-flow velocity field in a volume. Numerous parameters such as pulmonary arterial mean velocity, vessel distensibility, flow acceleration time and volume and tricuspid regurgitation peak velocity, as well as the duration and onset of vortical blood flow in the main pulmonary artery, have been explored to either diagnose PH or find non-invasive correlates to right heart catheter parameters. Furthermore, PC imaging-based analysis of pulmonary arterial pulse-wave velocities, wall shear stress and kinetic energy losses grants novel insights into cardiopulmonary remodelling in PH. This review aimed to outline the current applications of 2D and 4D PC imaging in PH and show why this technique has the potential to contribute significantly to early diagnosis and characterization of PH.

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“…The forward wave pattern contains an early systolic FCW and a late diastolic FEW, which is in line with previously found patterns in human pulmonary artery. The backward wave pattern contains a late systolic BCW, whereas in vivo studies report both backward expansion waves (BEW) and BCW [17,32,33]. It is hypothesised that a BEW is due to the considerable branching of the pulmonary artery and the result of an increase in total cross-sectional area [17,33], and a decrease in impedance, which is not included in our pulmonary model.…”

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confidence: 99%

A Mock Circulatory System Incorporating a Compliant 3D‐Printed Anatomical Model to Investigate Pulmonary Hemodynamics

Knoops

Biglino

Hughes³

et al. 2016

Artificial Organs

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A realistic mock circulatory system (MCS) could be a valuable in vitro testbed to study human circulatory hemodynamics. The objective of this study was to design a MCS replicating the pulmonary arterial circulation, incorporating an anatomically representative arterial model suitable for testing clinically relevant scenarios. A second objective of the study was to ensure the system's compatibility with magnetic resonance imaging (MRI) for additional measurements. A latex pulmonary arterial model with two generations of bifurcations was manufactured starting from a 3D-printed mold reconstructed from patient data. The model was incorporated into a MCS for in vitro hydrodynamic measurements. The setup was tested under physiological pulsatile flow conditions and results were evaluated using wave intensity analysis (WIA) to investigate waves traveling in the arterial system. Increased pulmonary vascular resistance (IPVR) was simulated as an example of one pathological scenario. Flow split between right and left pulmonary artery was found to be realistic (54 and 46%, respectively). No substantial difference in pressure waveform was observed throughout the various generations of bifurcations. Based on WIA, three main waves were identified in the main pulmonary artery (MPA), that is, forward compression wave, backward compression wave, and forward expansion wave. For IPVR, a rise in mean pressure was recorded in the MPA, within the clinical range of pulmonary arterial hypertension. The feasibility of using the MCS in the MRI scanner was demonstrated with the MCS running 2 h consecutively while Address correspondence and reprint requests to: Paul Knoops, 30 Guilford Street, London WC1N 1EH, UK. paul.knoops. 14@ucl.ac.uk. Author ContributionsConception and design of the work: PGMK, GB, ADH, SS, RT; experimental setup, data acquisition and analysis: PGMK, GB, LX; interpretation of the data: PGMK, GB, ADH, KHP, RT; drafting the manuscript: PGMK, GB, RT; all authors critically revised the manuscript, read and approved the final manuscript. Conflict of InterestThe authors declare no conflict of interest. Europe PMC Funders GroupAuthor Manuscript Artif Organs. Author manuscript; available in PMC 2017 July 15. Published in final edited form as:Artif Organs. 2017 July ; 41(7): 637-646. doi:10.1111/aor.12809. Europe PMC Funders Author ManuscriptsEurope PMC Funders Author Manuscripts acquiring preliminary MRI data. This study shows the development and verification of a pulmonary MCS, including an anatomically correct, compliant latex phantom. The setup can be useful to explore a wide range of hemodynamic questions, including the development of patientand pathology-specific models, considering the ease and low cost of producing rapid prototyping molds, and the versatility of the setup for invasive and noninvasive (i.e., MRI) measurements.Mock circulatory systems (MCS) are widely used to gather hydrodynamic data in vitro. They allow investigation of the cardiovascular system in both healthy and pathological scenarios, with t...

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Noninvasive pulmonary artery wave intensity analysis in pulmonary hypertension

Cited by 60 publications

References 37 publications

Feasibility of cardiovascular magnetic resonance derived coronary wave intensity analysis

Feasibility of cardiovascular magnetic resonance derived coronary wave intensity analysis

MR phase-contrast imaging in pulmonary hypertension

A Mock Circulatory System Incorporating a Compliant 3D‐Printed Anatomical Model to Investigate Pulmonary Hemodynamics

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