Coupling between the heart and arterial system in heart failure

doi:10.1016/0002-9343(91)90267-2

The American Journal of Medicine

Volume 90, Issue 5, Supplement 2, 29 May 1991, Pages S14-S18

https://doi.org/10.1016/0002-9343(91)90267-2 Get rights and content

Abstract

A number of experimental studies have demonstrated the optimal coupling between the ventricle and arterial load, under physiologic and pathologic circumstances, directed to produce maximal stroke work. We investigated matching of the ventricular properties, quantified by the slope of end-systolic pressure-volume relationship, with arterial load properties, expressed by the slope of end-systolic pressurestroke volume relationship. In normal subjects, with ejection fraction of ≥60%, ventricular elastance was nearly twice as large as arterial elastance. This condition affords maximal mechanical efficiency. In patients with moderate heart failure, with ejection fraction of 40–59%, ventricular elastance was almost equal to arterial elastance. This condition affords maximal stroke work from a given end-diastolic volume. In patients with severe heart failure, with ejection fraction of <40%, ventricular elastance was less than half of arterial elastance, which resulted in increased potential energy and decreased work efficiency. Ventriculoarterial coupling is normally set toward higher left ventricular work efficiency, whereas in patients with moderate cardiac dysfunction, ventricular and arterial properties are matched, in order to maximize stroke work at the expense of work efficiency. Neither the stroke work nor work efficiency is near maximum for patients with severe cardiac dysfunction.

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Cited by (20)

Decreased Pulmonary Arterial Proportional Pulse Pressure After Pulmonary Artery Catheter Optimization for Advanced Heart Failure Is Associated With Adverse Clinical Outcomes
2016, Journal of Cardiac Failure
This study evaluated the novel index pulmonary arterial proportional pulse pressure (PAPP) in the Evaluation Study of Congestive Heart Failure and Pulmonary Artery Catheterization Effectiveness (ESCAPE) trial.
Multivariable Cox proportional hazards and logistical regression were used to model 6-month death; death, transplantation, or left ventricular assist device (DTLVAD); and DTLVAD or heart failure rehospitalization (DTLVADHF) with respect to PAPP. Among 175 patients with final hemodynamic data, 15.5% and 33.9%, respectively, died in optimal PAPP (PAPP >0.50) and nonoptimal PAPP (PAPP ≤0.50) groups (P = .008), and PAPP was independently associated with death, DTLVAD, and DTLVADHF (P < .01 for all outcomes). The hypothesized logistic regression model with pulmonary capillary wedge pressure, creatinine, and nonoptimal PAPP had an area under the curve of 0.818 (P < .0001) for death. Furthermore, PAPP as a continuous variable was the most powerful predictor of DTLVADHF (hazard ratio 0.793 per 0.1 increase in PAPP [95% confidence interval 0.659–0.955], chi square 8.80; P = .01) in the Cox model, with no other clinical, laboratory, or hemodynamic parameters significant after adjustment for PAPP.
PAPP, a novel parameter for right-sided proportional pulse pressure, is an independent and powerful predictor of adverse clinical outcomes in advanced HF. Increased PAPP promises to be a useful therapeutic target in patients with pulmonary arterial pressure assessment.
Ventricular-arterial coupling, remodeling, and prognosis in chronic heart failure
2013, Journal of the American College of Cardiology
Citation Excerpt :
For maximal cardiac work, power, and efficiency, the coupling ratio of Ea/Ees typically resides between 0.5 and 1.2 (15,16). In failing hearts, this ratio increases as cardiac function declines and arterial load increases to maintain systolic pressure (17–20). At excessively high ratios, ventricular-vascular matching is significantly compromised, leading to inefficient and ineffective contraction (21).
The objective of this study was to compare the physiological determinants of ejection fraction (EF)—ventricular size, contractile function, and ventricular-arterial (VA) interaction—and their associations with clinical outcomes in chronic heart failure (HF).
EF is a potent predictor of HF outcomes, but represents a complex summary measure that integrates several components including left ventricular size, contractile function, and VA coupling. The relative importance of each of these parameters in determining prognosis is unknown.
In 466 participants with chronic systolic HF, we derived quantitative echocardiographic measures of EF: cardiac size (end-diastolic volume [EDV]); contractile function (the end-systolic pressure volume relationship slope [Ees_sb] and intercept [V₀]); and VA coupling (arterial elastance [Ea]/Ees_sb). We determined the association between these parameters and the following adverse outcomes: 1) the combined endpoint of death, cardiac transplantation, or ventricular assist device (VAD) placement; and 2) cardiac hospitalization.
Over a median follow-up of 3.4 years, there were 76 deaths, 52 transplantations, 14 VAD placements, and 684 cardiac hospitalizations. EF was independently associated with death, transplantation, and VAD placement (adjusted hazard ratio [HR]: 3.0; 95% confidence interval [CI]: 1.8 to 5.0 comparing third and first tertiles), as were EDV (HR: 2.6; 95% CI: 1.5 to 4.2); V₀ (HR: 3.6; 95% CI: 2.1 to 6.1); and Ea/Ees_sb (HR: 2.1; 95% CI: 1.3 to 3.3). EDV, V₀, and Ea/Ees_sb were also associated with risk of cardiac hospitalization. Ees_sb was not significantly associated with any adverse outcomes in adjusted analyses.
Left ventricular size, V₀, and VA coupling are associated with prognosis in systolic HF, but end-systolic elastance (Ees_sb) is not. Assessment of VA coupling via Ea/Ees_sb is an additional noninvasively derived metric that can be used to gauge prognosis in human HF.
Characterizing the right ventricle: Advancing our knowledge
2012, American Journal of Cardiology
Citation Excerpt :
In the normal LV, the aorta acts as an energy reservoir during systole and delivers energy back during diastole, which allows the LV to be relatively well coupled with the aorta. Studies in multiple animal models and humans have demonstrated that, despite the pulsatile nature of LV pump function, virtually all the energy expended is ultimately converted into flow energy as a consequence of the elastic recoil of the aorta.36,37 In contrast, in the RV 25%–40% of energy used by the RV is not converted to flow.38,39
Our ability to evaluate the right ventricle (RV) in pulmonary hypertension has traditionally been quite limited: the RV's complex anatomy is not adequately represented by 2-dimensional imaging, and our understanding of what is an adaptive and maladaptive RV response is incomplete. However, measures of RV function appear to be a strong predictor of survival in pulmonary hypertension. This is, therefore, a promising area for future study. To more fully understand the challenges and opportunities in this area, this article provides a review of RV embryology and anatomy, current assessment of the RV function, animal models of RV function, RV–pulmonary artery coupling, and how translating lessons from studies of the left ventricle may increase our knowledge of the RV.
Chronic cardiac failure: Physiology and treatment
2010, Paediatric Cardiology
Arterial elastance and heart-arterial coupling in aortic regurgitation are determined by aortic leak severity
2002, American Heart Journal
Citation Excerpt :
For all other cases, pump efficiency is lower than the theoretically predicted value based on Ea/Emax. The use of effective arterial elastance and of Ea/Emax has been promoted by theoretical and experimental studies linking Ea/Emax to LV mechanico-energetics.3,4,6-10,12 Note, however, that Ea/Emax is mainly a “geometrical” parameter related to ventricular volume.
Background In aortic valve regurgitation (AR), aortic leak severity modulates left ventricle (LV) arterial system interaction. The aim of this study was to assess (1) how arterial elastance (E_a), calculated as the ratio of LV end-systolic pressure and stroke volume, relates to arterial properties and leak severity and (2) the validity of E_a/E_max (with E_max the slope of the end-systolic pressure-volume relation) as a heart-arterial coupling parameter in AR. Methods and Results Our work is based on human data obtained from a study on vascular adaptation in chronic AR. These data allowed us to assess the parameters of a computer model of heart-arterial interaction. In particular, total peripheral resistance (R) and aortic leak severity—expressed as leak resistance (R_L,ao)—were quantified for different patient subgroups (group I/IIa/IIb: E_max = 2.15/0.62/0.47 mm Hg/mL; E_a = 1.24/0.66/0.90 mm Hg/mL; R = 1.9/0.6/0.85 mm Hg·s/mL, R_L,ao = 0.35/0.05/0.20 mm Hg·s/mL). A parameter study demonstrated that R_L,ao was the main determinant of E_a. With all other parameters constant, valve repair would increase E_a to 2.81, 1.08, and 1.54 mm Hg/mL in groups I, IIa, and IIb, respectively. For a given E_a/E_max, LV pump efficiency (estimated as the ratio of stroke work and LV systolic pressure-volume area) was lower than the theoretical predicted value, except for the simulations with intact aortic valve. Conclusions In AR, E_a is determined by aortic leak severity rather than by arterial system properties. Using E_a/E_max as a coupling parameter in general or as a mechanico-energetic regulatory parameter in particular is questionable. (Am Heart J 2002;144:568-76.)
Ventriculo-arterial coupling detects occult RV dysfunction in chronic thromboembolic pulmonary vascular disease
2017, Physiological Reports

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Coupling between the heart and arterial system in heart failure

Abstract

Am J Cardiol

Does normal pulmonary impedance constitute the optimal load for the right ventricle?

Am J Physiol

Interaction between heart as a pump and artery as a load

Jpn Circ J

Left ventricular interaction with arterial load studied in isolated canine heart

Am J Physiol

Flow and power output of right ventricle facing load with variable input impedance

Am J Physiol

Optimal power generation by the left ventricle: A study in the anesthetized open thorax cat

Circ Res