scholarly journals The Use of Maximum Entropy to Enhance Wave Intensity Analysis: An Application to Coronary Arteries in Hypertrophic Obstructive Cardiomyopathy

2021 ◽  
Vol 8 ◽  
Author(s):  
Nadine Francis ◽  
Peter P. Selwanos ◽  
Magdi H. Yacoub ◽  
Kim H. Parker
Keyword(s):  
Maximum Entropy ◽  
Coronary Arteries ◽  
Hypertrophic Obstructive Cardiomyopathy ◽  
Entropy Method ◽  
Wave Intensity ◽  
Positive Sign ◽  
Intensity Analysis ◽  
Wave Intensity Analysis ◽  
Compression Waves ◽  
Naming Convention

Background: Wave intensity analysis is useful for analyzing coronary hemodynamics. Much of its clinical application involves the identification of waves indicated by peaks in the wave intensity and relating their presence or absence to different cardiovascular events. However, the analysis of wave intensity peaks can be problematic because of the associated noise in the measurements. This study shows how wave intensity analysis can be enhanced by using a Maximum Entropy Method (MEM).Methods: We introduce a MEM to differentiate between “peaks” and “background” in wave intensity waveforms. We apply the method to the wave intensity waveforms measured in the left anterior descending coronary artery from 10 Hypertrophic Obstructive Cardiomyopathy (HOCM) and 11 Controls with normal cardiac function. We propose a naming convention for the significant waves and compare them across the cohorts.Results: Using a MEM enhances wave intensity analysis by identifying twice as many significant waves as previous studies. The results are robust when MEM is applied to the log transformed wave intensity data and when all of the measured data are used. Comparing waves across cohorts, we suggest that the absence of a forward expansion wave in HOCM can be taken as an indication of HOCM. Our results also indicate that the backward compression waves in HOCM are significantly larger than in Controls; unlike the forward compression waves where the wave energy in Controls is significantly higher than in HOCM. Comparing the smaller secondary waves revealed by MEM, we find some waves that are present in the majority of Controls and absent in almost all HOCM, and other waves that are present in some HOCM patients but entirely absent in Controls. This suggests some diagnostic utility in the clinical measurement of these waves, which can be a positive sign of HOCM or a subgroup with a particular pathology.Conclusion: The MEM enhances wave intensity analysis by identifying many more significant waves. The method is novel and can be applied to wave intensity analysis in all arteries. As an example, we show how it can be useful in the clinical study of hemodynamics in the coronary arteries in HOCM.

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

2014 ◽  
Vol 109 (2) ◽  
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

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

2008 ◽  
Vol 295 (3) ◽  
pp. H1198-H1205 ◽  
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.

Direct and series transmission of left atrial pressure perturbations to the pulmonary artery: a study using wave-intensity analysis

2004 ◽  
Vol 286 (1) ◽  
pp. H267-H275 ◽  
Author(s):  
Ellen H. Hollander ◽  
Gary M. Dobson ◽  
Jiun-Jr Wang ◽  
Kim H. Parker ◽  
John V. Tyberg
Keyword(s):  
Pulmonary Artery ◽  
Left Ventricular ◽  
Wave Intensity ◽  
Pulmonary Vasculature ◽  
Pressure Waves ◽  
Intensity Analysis ◽  
Wave Intensity Analysis ◽  
Compression Waves ◽  
In Series ◽  
Late Systole

Pressure waves are thought to travel from the left atrium (LA) to the pulmonary artery (PA) only retrogradely, via the vasculature. In seven anesthetized open-chest dogs, a balloon was placed in the LA, which was rapidly inflated and deflated during diastole, early systole, and late systole. High-fidelity pressures were measured within and around the heart. Measurements were made at low volume [LoV; left ventricular end-diastolic pressure (LVEDP) = 5–9 mmHg], high volume (HiV; LVEDP = 16–19 mmHg), and HiV with the pericardium removed. Wave-intensity analysis demonstrated that, except during late systole, balloon inflation created forward-going PA compression waves that were transmitted directly through the heart without measurable delay; backward PA compression waves were transmitted in-series through the pulmonary vasculature and arrived after delays of 90 ± 3 ms (HiV) and 103 ± 5 ms (LoV; P < 0.05). Direct transmission was greater during diastole, and both direct and series transmission increased with volume loading. Pressure waves from the LA arrive in the PA by two distinct routes: rapidly and directly through the heart and delayed and in-series through the pulmonary vasculature.

scholarly journals Potential and limitations of wave intensity analysis in coronary arteries

2009 ◽  
Vol 47 (2) ◽  
pp. 233-239 ◽  
Author(s):  
Maria Siebes ◽  
Christina Kolyva ◽  
Bart-Jan Verhoeff ◽  
Jan J. Piek ◽  
Jos A. Spaan
Keyword(s):  
Coronary Arteries ◽  
Wave Intensity ◽  
Intensity Analysis ◽  
Wave Intensity Analysis

Angiographic evidence of backward compression wave: systolic compression of septal perforators in a child with hypertrophic cardiomyopathy

2020 ◽  
pp. 1-2
Author(s):  
Rupesh Natarajan ◽  
Rebecca Ameduri ◽  
Massimo Griselli ◽  
Varun Aggarwal
Keyword(s):  
Hypertrophic Cardiomyopathy ◽  
Coronary Arteries ◽  
Compression Wave ◽  
Poor Prognosis ◽  
Wave Intensity ◽  
Compressive Deformation ◽  
Intensity Analysis ◽  
Wave Intensity Analysis ◽  
Angiographic Evidence

Abstract Intracoronary wave intensity analysis in hypertrophic cardiomyopathy has shown a large backward compression wave due to compressive deformation of the intramyocardial coronary arteries in systole. The authors describe the angiographic evidence of this backward compression wave, which has not been described in this physiological context and can be a marker of poor prognosis.

scholarly journals Noninvasive wave intensity analysis predicts functional worsening in children with pulmonary arterial hypertension

2018 ◽  
Vol 315 (4) ◽  
pp. H968-H977 ◽  
Author(s):  
Michal Schäfer ◽  
Neil Wilson ◽  
D. Dunbar Ivy ◽  
Richard Ing ◽  
Steven Abman ◽  
...  
Keyword(s):  
Pulmonary Arterial Hypertension ◽  
Arterial Hypertension ◽  
Wave Intensity ◽  
Vascular Stiffness ◽  
Intensity Analysis ◽  
Wave Intensity Analysis ◽  
Compression Waves ◽  
Control Subjects ◽  
Healthy Control ◽  
Pulmonary Arterial

The purpose of the present study was to characterize pulmonary vascular stiffness using wave intensity analysis (WIA) in children with pulmonary arterial hypertension (PAH), compare the WIA indexes with catheterization- and MRI-derived hemodynamics, and assess the prognostic ability of WIA-derived biomarkers to predict the functional worsening. WIA was performed in children with PAH ( n = 40) and healthy control subjects ( n = 15) from phase-contrast MRI-derived flow and area waveforms in the main pulmonary artery (MPA). From comprehensive WIA spectra, we collected and compared with healthy control subjects forward compression waves (FCW), backward compression waves (BCW), forward decompression waves (FDW), and wave propagation speed ( c-MPA). There was no difference in the magnitude of FCW between PAH and control groups (88 vs. 108 mm5·s−1·ml−1, P = 0.239). The magnitude of BCW was increased in patients with PAH (32 vs. 5 mm5·s−1·ml−1, P < 0.001). There was no difference in magnitude of indexed FDW (32 vs. 28 mm5·s−1·ml−1, P = 0.856). c-MPA was increased in patients with PAH (3.2 vs. 1.6 m/s, P < 0.001). BCW and FCW correlated with mean pulmonary arterial pressure, right ventricular volumes, and ejection fraction. Elevated indexed BCW [heart rate (HR) = 2.91, confidence interval (CI): 1.18–7.55, P = 0.019], reduced indexed FDW (HR = 0.34, CI: 0.11–0.90, P = 0.030), and increased c-MPA (HR = 3.67, CI: 1.47–10.20, P = 0.004) were strongly associated with functional worsening of disease severity. Our results suggest that noninvasively derived biomarkers of pulmonary vascular resistance and stiffness may be helpful for determining prognosis and monitoring disease progression in children with PAH. NEW & NOTEWORTHY Wave intensity analysis (WIA) studies are lacking in children with pulmonary arterial hypertension (PAH) partially because WIA, which is necessary to assess vascular stiffness, requires an invasive pressure-derived waveform along with simultaneous flow measurements. We analyzed vascular stiffness using WIA in children with PAH who underwent phase-contrast MRI and observed significant differences in WIA indexes between patients with PAH and control subjects. Furthermore, WIA indexes were predictive of functional worsening and were associated with standard catheterization measures.

scholarly journals Estimation of coronary wave intensity analysis using noninvasive techniques and its application to exercise physiology

2016 ◽  
Vol 310 (5) ◽  
pp. H619-H627 ◽  
Author(s):  
Christopher J. Broyd ◽  
Sukhjinder Nijjer ◽  
Sayan Sen ◽  
Ricardo Petraco ◽  
Siana Jones ◽  
...  
Keyword(s):  
Coronary Circulation ◽  
Exercise Physiology ◽  
Left Ventricular ◽  
Wave Intensity ◽  
Concordance Correlation Coefficient ◽  
Intensity Analysis ◽  
Wave Intensity Analysis ◽  
Concordance Correlation ◽  
Decompression Wave ◽  
Pulsed Wave Doppler

Wave intensity analysis (WIA) has found particular applicability in the coronary circulation where it can quantify traveling waves that accelerate and decelerate blood flow. The most important wave for the regulation of flow is the backward-traveling decompression wave (BDW). Coronary WIA has hitherto always been calculated from invasive measures of pressure and flow. However, recently it has become feasible to obtain estimates of these waveforms noninvasively. In this study we set out to assess the agreement between invasive and noninvasive coronary WIA at rest and measure the effect of exercise. Twenty-two patients (mean age 60) with unobstructed coronaries underwent invasive WIA in the left anterior descending artery (LAD). Immediately afterwards, noninvasive LAD flow and pressure were recorded and WIA calculated from pulsed-wave Doppler coronary flow velocity and central blood pressure waveforms measured using a cuff-based technique. Nine of these patients underwent noninvasive coronary WIA assessment during exercise. A pattern of six waves were observed in both modalities. The BDW was similar between invasive and noninvasive measures [peak: 14.9 ± 7.8 vs. −13.8 ± 7.1 × 104 W·m−2·s−2, concordance correlation coefficient (CCC): 0.73, P < 0.01; cumulative: −64.4 ± 32.8 vs. −59.4 ± 34.2 × 102 W·m−2·s−1, CCC: 0.66, P < 0.01], but smaller waves were underestimated noninvasively. Increased left ventricular mass correlated with a decreased noninvasive BDW fraction ( r = −0.48, P = 0.02). Exercise increased the BDW: at maximum exercise peak BDW was −47.0 ± 29.5 × 104 W·m−2·s−2 ( P < 0.01 vs. rest) and cumulative BDW −19.2 ± 12.6 × 103 W·m−2·s−1 ( P < 0.01 vs. rest). The BDW can be measured noninvasively with acceptable reliably potentially simplifying assessments and increasing the applicability of coronary WIA.

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

2007 ◽  
Vol 292 (3) ◽  
pp. H1533-H1540 ◽  
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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