Kinematic Modeling-based Left Ventricular Diastatic (Passive) Chamber Stiffness Determination with In-Vivo Validation

Mossahebi, Sina; Kovács, Sándor J.

doi:10.1007/s10439-011-0458-3

Cited by 11 publications

(7 citation statements)

References 43 publications

(68 reference statements)

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“…The lack of correlation of the deceleration time with passive PV curve parameters observed in our study is probably related to its sensitivity to relaxation (32). Operating stiffness during diastasis can also be accurately determined by fitting the transmitral flow spectrogram to a kinematic mathematical model (19). Despite the fact that LV relaxation is still frequently not completed during this phase (Fig.…”

Section: Discussionmentioning

confidence: 84%

“…Moreover, our method has an additional advantage over these previous single-beat approximations. Because the algorithm processes data from multiple beats in an integral fashion, the spontaneous variations in load caused by breathing (19) can be incorporated in future developments. For these reasons, we believe that global optimization is the most accurate method available to date to characterize diastolic properties in vivo without the need of occluding the vena cava.…”

Section: Discussionmentioning

confidence: 99%

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Diastolic chamber properties of the left ventricle assessed by global fitting of pressure-volume data: improving the gold standard of diastolic function

Bermejo

Yotti

Villar

et al. 2013

Journal of Applied Physiology

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.-In cardiovascular research, relaxation and stiffness are calculated from pressurevolume (PV) curves by separately fitting the data during the isovolumic and end-diastolic phases (end-diastolic PV relationship), respectively. This method is limited because it assumes uncoupled active and passive properties during these phases, it penalizes statistical power, and it cannot account for elastic restoring forces. We aimed to improve this analysis by implementing a method based on global optimization of all PV diastolic data. In 1,000 Monte Carlo experiments, the optimization algorithm recovered entered parameters of diastolic properties below and above the equilibrium volume (intraclass correlation coefficients ϭ 0.99). Inotropic modulation experiments in 26 pigs modified passive pressure generated by restoring forces due to changes in the operative and/or equilibrium volumes. Volume overload and coronary microembolization caused incomplete relaxation at end diastole (active pressure Ͼ 0.5 mmHg), rendering the end-diastolic PV relationship method ill-posed. In 28 patients undergoing PV cardiac catheterization, the new algorithm reduced the confidence intervals of stiffness parameters by one-fifth. The Jacobian matrix allowed visualizing the contribution of each property to instantaneous diastolic pressure on a per-patient basis. The algorithm allowed estimating stiffness from single-beat PV data (derivative of left ventricular pressure with respect to volume at end-diastolic volume intraclass correlation coefficient ϭ 0.65, error ϭ 0.07 Ϯ 0.24 mmHg/ml). Thus, in clinical and preclinical research, global optimization algorithms provide the most complete, accurate, and reproducible assessment of global left ventricular diastolic chamber properties from PV data. Using global optimization, we were able to fully uncouple relaxation and passive PV curves for the first time in the intact heart. diastolic function; hemodynamics; relaxation; diastolic stiffness; mechanical properties; left ventricle; pressure; diastole DIASTOLIC DYSFUNCTION is present to some degree in virtually all structural myocardial diseases, and, independent of its primary cause, this condition per se has become a major source of cardiovascular morbidity and mortality (23). Although the physiology of diastole has been a key field of preclinical research for decades, all treatments aimed to improve clinical outcome on the basis of modifying diastolic properties have been unsuccessful (8). Diastolic dysfunction is a generic term designating diverse abnormalities of left ventricular (LV) mechanical chamber properties, which all share a final stage of elevated left atrial pressure, pulmonary congestion, and heart failure. To improve therapeutic strategies, it is recognized that developing independent, unbiased, and robust indexes of each intrinsic diastolic property is mandatory (16).At the full-organ integration level, the analysis of LV pressure-volume (PV) data obtained during acute load manipulation is the current gold standard method for assessing di...

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Section: Discussionmentioning

confidence: 84%

Section: Discussionmentioning

confidence: 99%

Diastolic chamber properties of the left ventricle assessed by global fitting of pressure-volume data: improving the gold standard of diastolic function

Bermejo

Yotti

Villar

et al. 2013

Journal of Applied Physiology

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“…43 In contrast, the PDF approach accurately predicts elevated ventricular filling pressures in patients with normal ejection fraction and diastolic dysfunction. 21–23 This technique is causality based (on the suction pump attribute of the left ventricle), and is unique in its ability to quantify diastolic function in terms of relaxation, stiffness, and load as determinants of transmitral flow.…”

Section: Discussionmentioning

confidence: 99%

Low-Sodium DASH Diet Improves Diastolic Function and Ventricular–Arterial Coupling in Hypertensive Heart Failure With Preserved Ejection Fraction

Hummel

Seymour

Brook

et al. 2013

Circ: Heart Failure

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159

107

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Background Heart failure with preserved ejection fraction (HFPEF) involves failure of cardiovascular reserve in multiple domains. In HFPEF animal models, dietary sodium restriction improves ventricular and vascular stiffness and function. We hypothesized that the sodium-restricted Dietary Approaches to Stop Hypertension diet (DASH/SRD) would improve left ventricular diastolic function, arterial elastance, and ventricular-arterial (V-A) coupling in hypertensive HFPEF. Methods and Results Thirteen patients with treated hypertension and compensated HFPEF consumed the DASH/SRD (target sodium 50 mmol/2100 kcal) for 21 days. We measured baseline and post-DASH/SRD brachial and central BP (via radial arterial tonometry), and cardiovascular function with echocardiographic measures (all previously invasively validated). Diastolic function was quantified via the Parametrized Diastolic Filling formalism, which yields relaxation/viscoelastic (c) and passive/stiffness (k) constants through analysis of Doppler mitral inflow velocity (E-wave) contours. Effective arterial elastance (Ea) end-systolic elastance (Ees), and V-A coupling (defined as the ratio Ees:Ea) were determined using previously published techniques. Wilcoxon matched-pairs tests were used for pre-post comparisons. The DASH/SRD reduced clinic and 24-hour brachial systolic pressure (155±35 to 138±30 and 130±16 to 123±18 mmHg, both p=.02) and central end-systolic pressure trended lower (116±18 to 111±16 mmHg, p=.12). In conjunction, diastolic function improved (c, 24.3±5.3 to 22.7±8.1 s−1;p=.03; k, 252±115 to 170±37 s−1;p=.03), Ea decreased (2.0±0.4 to 1.7±0.4 mmHg/ml;p=.007), and V-A coupling improved (Ees:Ea, 1.5±0.3 to 1.7±0.4;p=.04). Conclusions In hypertensive HFPEF patients, the sodium-restricted DASH diet was associated with favorable changes in ventricular diastolic function, arterial elastance, and V-A coupling.

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“…39 Beat-to-beat variation in diastatic volume and pressure generates a locus of P, V points whose slope via linear regression defines in vivo passive chamber stiffness, 39 easily determined directly from E-wave analysis. 40 Although pioneering work indicated that DT and stiffness 16 are inversely related, subsequent PDF analysis has refined that view by showing that E-wave DT is determined jointly by stiffness and relaxation (k and c PDF Figure 3. E-waves of 2 selected subjects (normal pattern, pseudonormal pattern) with indistinguishable E-wave duration, E peak , E/A ratio but significantly different values for PDF parameters (k and c) and stiffness and relaxation components of DT (DT s and DT r ).…”

Section: Pdf Analysis Of E-waves Diastolic Function and Dt Fractionmentioning

confidence: 99%

Fractionating E-Wave Deceleration Time Into Its Stiffness and Relaxation Components Distinguishes Pseudonormal From Normal Filling

Mossahebi

Zhu

Kovács

2015

Circ: Cardiovascular Imaging

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Background-Pseudonormal Doppler E-wave filling patterns indicate diastolic dysfunction but are indistinguishable from the normal filling pattern. For accurate classification, maneuvers to alter load or to additionally measure peak E′ are required. E-wave deceleration time (DT) has been fractionated into its stiffness (DT s ) and relaxation (DT r ) components (DT=DT s +DT r ) by analyzing E-waves via the parametrized diastolic filling formalism. The method has been validated with DT s and DT r correlating with simultaneous catheterization-derived stiffness (dP/dV) and relaxation (τ) with r=0.82 and r=0.94, respectively. We hypothesize that DT fractionation can (1) distinguish between unblinded (E′ known) normal versus pseudonormal age-matched groups with normal left ventricular ejection fraction, and (2) distinguish between blinded (E′ unknown) normal versus pseudonormal groups, based solely on E-wave analysis. Methods and Results-Data (763 E-waves) from 15 age-matched, pseudonormal (elevated E/E′) and 15 normal subjects were analyzed. Conventional echocardiographic and parametrized diastolic filling stiffness (k) and relaxation (c) parameters and DT s and DT r were compared. Conventional diastolic function parameters did not differentiate between unblinded groups, whereas k, c (P<0.001) and DT s , DT r (P<0.001) did. Independent, blinded (E′ not provided) analysis of 42 subjects (30 subjects from unblinded training set and 12 additional subjects from validation set, 581 E-waves) showed that R (=DT r /DT) had high sensitivity (0.90) and specificity (0.86) in differentiating pseudonormal from normal once E′ revealed actual classification. Conclusions-Parametrized diastolic filling-based E-wave analysis (k, c or DT s and DT r ) can differentiate normal versus pseudonormal filling patterns without requiring knowledge of E′. (Circ Cardiovasc Imaging. 2015;8:e002177.

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Kinematic Modeling-based Left Ventricular Diastatic (Passive) Chamber Stiffness Determination with In-Vivo Validation

Cited by 11 publications

References 43 publications

Diastolic chamber properties of the left ventricle assessed by global fitting of pressure-volume data: improving the gold standard of diastolic function

Diastolic chamber properties of the left ventricle assessed by global fitting of pressure-volume data: improving the gold standard of diastolic function

Low-Sodium DASH Diet Improves Diastolic Function and Ventricular–Arterial Coupling in Hypertensive Heart Failure With Preserved Ejection Fraction

Fractionating E-Wave Deceleration Time Into Its Stiffness and Relaxation Components Distinguishes Pseudonormal From Normal Filling

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