Ventricular-vascular interaction in heart failure

Percent Predicted Peak Exercise Oxygen Pulse Provides Insights Into Ventricular-Vascular Response and Prognosticates HFpEF

Background

Peak oxygen consumption and oxygen pulse along with their respective percent predicted measures are gold standards of exercise capacity. To date, no studies have investigated the relationship between percent predicted peak oxygen pulse (%PredO2P) and ventricular-vascular response (VVR) and the association of %PredO2P with all-cause mortality in heart failure with preserved ejection fraction (HFpEF) patients.

Objectives

The authors investigated the association between: 1) CPET measures of %PredO2P and VVR; and 2) %PredO2P and all-cause mortality in HFpEF patients.

Methods

Our cohort of 154 HFpEF patients underwent invasive CPET and were grouped into %PredO2P tertiles. The association between percent predicted Fick components and markers of VVR (ie, proportionate pulse pressure, effective arterial elastance) was determined with correlation analysis. The Cox proportional hazards model was used to identify predictors of mortality.

Results

The participants' mean age was 57 ± 15 years. Higher %PredO2P correlated with higher exercise capacity. In terms of VVR, higher %PredO2P correlated with a lower pressure for a given preload (effective arterial elastance r = -0.45, P < 0.001 and proportionate pulse pressure r = -0.22, P = 0.008). %PredO2P distinguished normal and abnormal percent predicted peak stroke volume and correlated positively with %PredVO2 (r = 0.61, P < 0.001). Participants had a median follow-up time of 5.6 years and 15% death. Adjusted for age and body mass index, there was a 5% relative reduction in mortality (HR: 0.95, 95% CI: 0.92-0.98, P = 0.003) for every percent increase in %PredO2P.

Conclusions

In HFpEF, %PredO2P is a VVR marker that can stratify invasive parameters such as percent predicted peak stroke volume. %PredO2P is an independent prognostic marker for all-cause mortality and those with higher %PredO2P exhibited longer survival.

Cardiorespiratory Instability after Percutaneous Patent Ductus Arteriosus Closure: A Multicenter Cohort Study

OBJECTIVE

To evaluate postprocedural clinical characteristics of preterm infants undergoing transcatheter patent ductus arteriosus (PDA) closure, including oxygenation/ventilation failure and cardiovascular compromise.

STUDY DESIGN

Multicenter retrospective cohort study of preterm infants who were ≤2 kg at the time of percutaneous PDA closure between August 2018 and July 2021. Indices of cardiorespiratory stability were collected pre-closure, immediately post-closure, and subsequently averaged every 4 hours for the first 24 hours post-procedure. The primary outcome was incidence of post-transcatheter cardiorespiratory syndrome: composite of hemodynamic instability (defined by systemic hypotension, systemic hypertension, or use of new inotropes/vasopressors in the first 24 hours after catheterization) and at least one of the following: (i) ventilation failure or (ii) oxygenation failure.

RESULTS

A total of 197 patients were included with a median [IQR] age and weight at catheterization of 34 [25, 43] days and 1090 [900, 1367] grams, respectively. The primary composite outcome of post-transcatheter cardiorespiratory syndrome was reported in 46 (23.3%).

CONCLUSION

Post-transcatheter cardiorespiratory syndrome is characterized primarily by systemic hypertension and oxygenation failure, with a very low incidence of hypotension and need for inotropes.

Identifying the Mechanisms of a Peripherally Limited Exercise Phenotype in Patients With Heart Failure With Preserved Ejection Fraction

BACKGROUND

We identified peripherally limited patients using cardiopulmonary exercise testing and measured skeletal muscle oxygen transport and utilization during invasive single leg exercise testing to identify the mechanisms of the peripheral limitation.

METHODS

Forty-five patients with heart failure with preserved ejection fraction (70±7 years, 27 females) completed seated upright cardiopulmonary exercise testing and were defined as having a (1) peripheral limitation to exercise if cardiac output/oxygen consumption (VO2) was elevated (≥6) or 5 to 6 with a stroke volume reserve >50% (n=31) or (2) a central limitation to exercise if cardiac output/VO2 slope was ≤5 or 5 to 6 with stroke volume reserve <50% (n=14). Single leg knee extension exercise was used to quantify peak leg blood flow (Doppler ultrasound), arterial-to-venous oxygen content difference (femoral venous catheter), leg VO2, and muscle oxygen diffusive conductance. In a subset of participants (n=36), phosphocreatine recovery time was measured by magnetic resonance spectroscopy to determine skeletal muscle oxidative capacity.

RESULTS

Peak VO2 during cardiopulmonary exercise testing was not different between groups (central: 13.9±5.7 versus peripheral: 12.0±3.1 mL/min per kg; P=0.135); however, the peripheral group had a lower peak arterial-to-venous oxygen content difference (central: 13.5±2.0 versus peripheral: 11.1±1.6 mLO2/dL blood; P<0.001). During single leg knee extension, there was no difference in peak leg VO2 (P=0.306), but the peripherally limited group had greater blood flow/VO2 ratio (P=0.024), lower arterial-to-venous oxygen content difference (central: 12.3±2.5 versus peripheral: 10.3±2.2 mLO2/dL blood; P=0.013), and lower muscle oxygen diffusive conductance (P=0.021). A difference in magnetic resonance spectroscopy-derived phosphocreatine recovery time was not detected (P=0.199).

CONCLUSIONS

Peripherally limited patients with heart failure with preserved ejection fraction identified by cardiopulmonary exercise testing have impairments in oxygen transport and utilization at the level of the skeletal muscle quantified by invasive knee extension exercise testing, which includes an increased blood flow/V̇O2 ratio and poor muscle diffusive capacity.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT04068844.

Reduced dynamic changes in pulmonary artery compliance during isometric handgrip exercise in patients with heart failure

Exercise intolerance is a debilitating symptom in heart failure (HF), adversely affecting both quality of life and long-term prognosis. Emerging evidence suggests that pulmonary artery (PA) compliance may be a contributing factor. This study aims to non-invasively assess PA compliance and its dynamic properties during isometric handgrip (HG) exercise in HF patients and healthy controls, using cardiovascular magnetic resonance (CMR). We prospectively enrolled 36 subjects, comprising 17 HF patients (NYHA class II and III) and 19 healthy controls. Participants performed an HG test, and we assessed changes in PA compliance and hemodynamic flow parameters using advanced CMR techniques. We also explored the relationship between CMR-derived PA compliance metrics and established clinical indicators, ensuring the validity of our findings through intra- and interobserver agreements. HF patients had significantly lower resting PA compliance compared to controls (28.9% vs. 50.1%, p < 0.01). During HG exercise, HF patients exhibited a dampened adaptability in PA compliance. Hemodynamic responses, including heart rate and blood pressure, were not significantly different between the groups. Further analyses revealed a significant correlation between changes in PA compliance and functional capacity, and an inverse relationship with NYHA class. Our study demonstrates a marked difference in PA vascular responses during HG exercise between HF patients and healthy controls. The compromised adaptability in PA compliance in HF patients is correlated with diminished functional capacity. These findings have significant clinical implications and may guide future interventional strategies in HF management.

Postoperative alterations in ventriculoarterial coupling are an indicator of cardiovascular outcomes in liver transplant recipients

BACKGROUND

Liver transplantation (LT) increases the heart and vessel workload in patients with cirrhotic cardiomyopathy. While the interaction of the left ventricle (LV) with the arterial system (ventriculoarterial coupling, VAC) is a key determinant of cardiovascular performance, little is known about changes in VAC after LT. Therefore, we evaluated the relationship between VAC after LT and cardiovascular outcomes.

METHODS

344 consecutive patients underwent echocardiographic assessments before and within 30 days after LT. Non-invasive arterial elastance (Ea), LV end-systolic elastance (Ees), and LV end-diastolic elastance (Eed) were calculated. The postoperative outcomes included the development of major adverse cardiovascular events (MACE) and the length of stay in the intensive care unit and hospital.

RESULTS

A total of 240 patients were included in the analyses. After LT, Ea increased by 16% (P < 0.001), and Ees and contractility index of systolic velocity (S') increased by 18% (P < 0.001) and 7% (P < 0.001), respectively. The Eed increased by 6% (P < 0.001). The VAC remained unchanged (0.56 to 0.56, P = 0.912). Of these patients, 29 had MACE, and those with MACE had significantly higher postoperative VAC. Additionally, a higher postoperative VAC was an independent risk factor for a longer postoperative hospital stay (P = 0.038).

CONCLUSIONS

These data suggest that ventriculoarterial decoupling is associated with poor postoperative outcomes after LT.

Update on the Use of Pulse Wave Velocity to Measure Age-Related Vascular Changes

PURPOSE OF REVIEW

Pulse wave velocity (PWV) is an important and well-established measure of arterial stiffness that is strongly associated with aging. Age-related alterations in the elastic properties and integrity of arterial walls can lead to cardiovascular disease. PWV measurements play an important role in the early detection of these changes, as well as other cardiovascular disease risk factors, such as hypertension. This review provides a comprehensive summary of the current knowledge of the effects of aging on arterial stiffness, as measured by PWV.

RECENT FINDINGS

This review highlights recent findings showing the applicability of PWV analysis for investigating heart failure, hypertension, and other cardiovascular diseases, as well as cerebrovascular diseases and Alzheimer's disease. It also discusses the clinical implications of utilizing PWV to monitor treatment outcomes, various challenges in implementing PWV assessment in clinical practice, and the development of new technologies, including machine learning and artificial intelligence, which may improve the usefulness of PWV measurements in the future. Measuring arterial stiffness through PWV remains an important technique to study aging, especially as the technology continues to evolve. There is a clear need to leverage PWV to identify interventions that mitigate age-related increases in PWV, potentially improving CVD outcomes and promoting healthy vascular aging.

Understanding clinical complexity in organ and organizational systems: Challenges local and global

INTRODUCTION

Complexity in healthcare systems has been arbitrarily defined as tasks or systems ranging from complicated to intractable, with a general view of these not being 'simple'. Complexity in healthcare systems in first-world countries has been well elucidated, however, data from third-world countries is still scant. MATERIALS AND METHODS: We present four cases each from three different organ systems-chronic kidney disease, alcohol use disorder, and heart failure-in the backdrop of our healthcare organization. We present our analysis of the complexities faced clinically and, in our local healthcare system which led to these events.

RESULTS

Analysis of these cases showed that patients with chronic kidney disease had vertebral-spinal pathologies due to poor infection control measures during haemodialysis. All these patients were young with a long history of secondary hypertension. In patients with alcohol use disorder, a common theme of how government regulations and peer pressure promote alcohol use is analysed. In the four patients with unexplained heart failure, vascular health is viewed as a fractal dimension and the various factors affecting vascular health are elaborated.

CONCLUSION

Complexities exist clinically in making a diagnosis, and organizationally, in the variables and nodes dictating patient outcomes. Clinical complexities cannot be simplified but have to be navigated in an optimized way to improve clinical outcomes.

Echocardiography Assessment of Left Ventricular Function in Extremely Preterm Infants, Born at Less Than 28 Weeks' Gestation, With Bronchopulmonary Dysplasia and Systemic Hypertension

BACKGROUND

The survival of smaller and more immature premature infants has been associated with lifelong cardiorespiratory comorbidities. Infants with bronchopulmonary dysplasia (BPD) undergo routine screening echocardiography to evaluate for development of chronic pulmonary hypertension, a late manifestation of pulmonary vascular disease.

METHODS

Our aim was to evaluate left ventricular (LV) performance in infants with BPD and pulmonary vascular disease who developed systemic hypertension. We hypothesized that infants with hypertension were more likely to have impaired LV performance. We present a single-center cross-sectional study of premature infants born at less than 28 0/7 weeks' gestational age with a clinical diagnosis of BPD. Infants were categorized by the systolic arterial pressure (SAP) at time of echocardiography as hypertensive (SAP ≥90 mm Hg) or normotensive (SAP <90 mm Hg). Sixty-four patients were included.

RESULTS

Infants with hypertension showed altered LV diastolic function with prolonged tissue Doppler imaging-derived isovolumic relaxation time (54.2 ± 5.1 vs 42.9 ± 8.2, P < .001), lower E:A, and higher E:e'. Indices of left heart volume/pressure loading (left atrium:aorta and LV end-diastolic volume [6.1 ± 2 vs 4.2 ± 1.2, P < .001]) were also higher in the hypertensive group. Finally, infants in the hypertensive group had higher pulmonary vascular resistance index (4.42 ± 1.1 vs 3.69 ± 0.8, P = .004).

CONCLUSIONS

We conclude that extremely preterm infants with BPD who develop systemic hypertension are at risk of abnormal LV diastolic dysfunction. Increased pulmonary vascular resistance index in the hypertensive group may relate to pulmonary venous hypertension secondary to LV dysfunction. This is an important consideration in this cohort when selecting the physiologically most appropriate treatment.

Effects of aging and endurance exercise training on cardiorespiratory fitness and cardiac structure and function in healthy midlife and older women

Cardiovascular disease (CVD) remains the leading cause of morbidity and mortality in women in developed societies. Unfavorable structural and functional adaptations within the heart and central blood vessels with sedentary aging in women can act as the substrate for the development of debilitating CVD conditions such as heart failure with preserved ejection fraction (HFpEF). The large decline in cardiorespiratory fitness, as indicated by maximal or peak oxygen uptake (V̇o2max and V̇o2peak, respectively), that occurs in women as they age significantly affects their health and chronic disease status, as well as the risk of cardiovascular and all-cause mortality. Midlife and older women who have performed structured endurance exercise training for several years or decades of their adult lives exhibit a V̇o2max and cardiac and vascular structure and function that are on par or even superior to much younger sedentary women. Therefore, regular endurance exercise training appears to be an effective preventative strategy for mitigating the adverse physiological cardiovascular adaptations associated with sedentary aging in women. Herein, we narratively describe the aging and short- and long-term endurance exercise training adaptations in V̇o2max, cardiac structure, and left ventricular systolic and diastolic function at rest and exercise in midlife and older women. The role of circulating estrogens on cardiac structure and function is described for consideration in the timing of exercise interventions to maximize beneficial adaptations. Current research gaps and potential areas for future investigation to advance our understanding in this critical knowledge area are highlighted.

Understanding heterogeneous mechanisms of heart failure with preserved ejection fraction through cardiorenal mathematical modeling

In contrast to heart failure (HF) with reduced ejection fraction (HFrEF), effective interventions for HF with preserved ejection fraction (HFpEF) have proven elusive, in part because it is a heterogeneous syndrome with incompletely understood pathophysiology. This study utilized mathematical modeling to evaluate mechanisms distinguishing HFpEF and HFrEF. HF was defined as a state of chronically elevated left ventricle end diastolic pressure (LVEDP > 20mmHg). First, using a previously developed cardiorenal model, sensitivities of LVEDP to potential contributing mechanisms of HFpEF, including increased myocardial, arterial, or venous stiffness, slowed ventricular relaxation, reduced LV contractility, hypertension, or reduced venous capacitance, were evaluated. Elevated LV stiffness was identified as the most sensitive factor. Large LV stiffness increases alone, or milder increases combined with either decreased LV contractility, increased arterial stiffness, or hypertension, could increase LVEDP into the HF range without reducing EF. We then evaluated effects of these mechanisms on mechanical signals of cardiac outward remodeling, and tested the ability to maintain stable EF (as opposed to progressive EF decline) under two remodeling assumptions: LV passive stress-driven vs. strain-driven remodeling. While elevated LV stiffness increased LVEDP and LV wall stress, it mitigated wall strain rise for a given LVEDP. This suggests that if LV strain drives outward remodeling, a stiffer myocardium will experience less strain and less outward dilatation when additional factors such as impaired contractility, hypertension, or arterial stiffening exacerbate LVEDP, allowing EF to remain normal even at high filling pressures. Thus, HFpEF heterogeneity may result from a range of different pathologic mechanisms occurring in an already stiffened myocardium. Together, these simulations further support LV stiffening as a critical mechanism contributing to elevated cardiac filling pressures; support LV passive strain as the outward dilatation signal; offer an explanation for HFpEF heterogeneity; and provide a mechanistic explanation distinguishing between HFpEF and HFrEF.

Due Diligence of a Diastolic Index as a Prognostic Factor in Heart Failure with Preserved Ejection Fraction

Of the existing non-invasive diastolic indices, none consider arterial load. This article reveals points of caution for determining the diastolic prognostic index using a novel index of vascular resistance-integrated diastolic function in old, real-world patients with heart failure with preserved ejection fraction (HFpEF) in Japan. This index represents the ratio of left ventricular diastolic elastance (Ed) to arterial elastance (Ea), where Ed/Ea = (E/e')/(0.9 × systolic blood pressure), showing a relative ratio of left atrial filling pressure to left ventricular end-systolic pressure. The role of hemodynamic prognostic factors related to diastolic function, such as Ed/Ea, may differ according to the clinical endpoint, follow-up duration, and sex. In HFpEF patients with heterogenous cardiac structure and function, an assessment using a serial echocardiographic diastolic index in clinical care can provide an accurate prognosis.

The evaluation of cardiac functions in deep Trendelenburg position during robotic-assisted laparoscopic prostatectomy

Objective

This study aimed to demonstrate the reliability of the cardiac cycle efficiency value through its correlation with longitudinal strain by observing the effect of the deep Trendelenburg position.

Design

A prospective, observational study.

Setting

Single center.

Participants

Between May and September 2022, the hemodynamic parameters of 30 patients who underwent robotic assisted laparoscopic prostatectomy under general anesthesia were prospectively evaluated.

Measurements and main results

All invasive cardiac monitoring parameters and longitudinal strain achieved transesophageal echocardiography were recorded in pre-deep Trendelenburg position (T3) and 10th minute of deep Trendelenburg position (T4). Delta values were calculated for the cardiac cycle efficiency and longitudinal strain (values at T4 minus values at T3). The estimated power was calculated as 0.99 in accordance with the cardiac cycle efficiency values at T3 and T4 (effect size: 0.85 standard deviations of the mean difference: 0.22, alpha: 0.05). At T4, heart rate, pulse pressure variation, cardiac cycle efficiency, dP/dt and longitudinal strain were significantly lower than those at T3 (p = 0.009, p < 0.001, p < 0.001, and p < 0.001, respectively). There was a positive correlation between the delta-cardiac cycle efficiency and delta-longitudinal strain (R2 = 0.36, p < 0.001).

Conclusion

Although the absence of significant changes in mean arterial pressure and cardiac index after Trendelenburg position suggests that cardiac workload has not changed, changes in cardiac cycle efficiency and longitudinal strain indicate increased cardiac workload due to increased ventriculo-arterial coupling.

Association Between Endothelial Dysfunction and Left Ventricular Diastolic Stiffness - Subanalysis of the Flow-Mediated Dilation Japan (FMD-J) Study

BACKGROUND

Endothelial dysfunction and increased left ventricular (LV) stiffness are associated with the incidence of heart failure with preserved ejection fraction (HFpEF). This study evaluated the association between endothelial dysfunction and LV diastolic stiffness.

METHODS AND RESULTS

Endothelial dysfunction evaluated by flow-medicated vasodilation (FMD) and the reactive hyperemia index (RHI), which reflects endothelial dysfunction in the microvasculature, was measured in 112 subjects with hypertension in the Flow-Mediated Dilation Japan (FMD-J) study. Using transthoracic echocardiography, LV diastolic stiffness was evaluated by measuring diastolic wall strain (DWS) in the LV posterior wall. In this cross-sectional study, associations among FMD, RHI, and DWS were investigated using multiple regression analyses. The mean (±SD) age of the subjects 65±9 years, and 63% were men. DWS was significantly associated with RHI, but not FMD, on multivariate linear regression analysis (β=0.39; P<0.0001). This association was preserved in subjects without LV hypertrophy (β=0.46; P<0.0001). A DWS ≤median, suggesting increased LV diastolic stiffness, was significantly associated with RHI on multivariate logistic regression analysis (odds ratio 20.58; 95% confidence interval 4.83-87.63; P<0.0001). The receiver operating characteristic curve presented a cut-off value of 2.21 for RHI, with a sensitivity of 77% and a specificity of 71%, for DWS ≤median.

CONCLUSIONS

RHI, rather than FMD, was associated with DWS. Endothelial dysfunction in the microvasculature may be associated with increased LV diastolic stiffness.

Impact of Hemodialysis on Left Ventricular-Arterial Coupling in End-Stage Renal Disease Patients

INTRODUCTION

As a key determinant of cardiovascular performance, vascular-arterial coupling (VAC) has been reported to be a predictor of clinical outcomes in various clinical scenarios. However, few studies have explored how acute fluid removal during hemodialysis (HD) impacts the interaction between cardiac function and the arterial system.

METHODS

We recruited 317 HD patients from an established renal dialysis unit for this cross-sectional study and a total of 285 were included in the final analyses. We measured left ventricle end-systolic elastance (Ees), the effective arterial elastance (Ea), and VAC before and after HD using noninvasive echocardiographic measurements. We also compared echocardiographic and hemodynamic parameters in ventriculo-arterial coupling and ventriculo-arterial uncoupling patients.

RESULTS

HD significantly altered partial ventricular and vascular function parameters such as blood pressure, left ventricular end-diastolic volume, stroke volume, left ventricular ejection fraction, and systemic vascular resistance index. Ea increased following HD from 3.5 ± 1.4 to 4.2 ± 1.8 mm Hg/mL (p < 0.0001), Ees increased following HD from 7.9 ± 5.5 to 9.2 ± 6.9 mm Hg/mL (p = 0.04), whereas VAC did not markedly alter as a result of HD. Ventriculo-arterial uncoupling was found to be related to abnormal cardiac structure and worse systolic function.

CONCLUSIONS

VAC obtained from echocardiography is likely to be load-independent and useful as a reliable index for stratifying the risk of cardiovascular diseases in HD patients. Further investigations on larger patient cohorts are needed to further validate our findings.

Biventricular cardiac power reserve in heart failure with preserved ejection fraction

AIMS

Cardiac and extracardiac abnormalities play important roles in heart failure with preserved ejection fraction (HFpEF). Biventricular cardiac power output (BCPO) quantifies the total rate of hydraulic work performed by both ventricles, suggesting that it may help to identify patients with HFpEF and more severe cardiac impairments to better individualize treatment.

METHODS AND RESULTS

Patients with HFpEF (n = 398) underwent comprehensive echocardiography and invasive cardiopulmonary exercise testing. Patients were categorized as low BCPO reserve (n = 199, < median of 1.57 W) or preserved BCPO reserve (n = 199). As compared to those with preserved BCPO reserve, those with low reserve were older and leaner, with more atrial fibrillation, higher N-terminal pro-B-type natriuretic peptide levels, worse renal function, more impaired left ventricular (LV) global longitudinal strain, worse LV diastolic function and right ventricular longitudinal function. Cardiac filling pressures and pulmonary artery pressures at rest were higher in low BCPO reserve, but central pressures were similar during exercise to those with preserved BCPO reserve. Exertional systemic and pulmonary vascular resistances were higher and exercise capacity was more impaired in those with low BCPO reserve. Reduced BCPO reserve was associated with increased risk for the composite endpoint of heart failure hospitalization or death over 2.9 (interquartile range 0.9-4.5) years of follow-up (hazard ratio 2.77, 95% confidence interval 1.73-4.42, p < 0.0001).

CONCLUSIONS

Inability to enhance BCPO during exercise is associated with more advanced HFpEF, increased systemic and pulmonary vascular resistance, reduced exercise capacity and increased adverse events in patients with HFpEF. Novel therapies that enhance biventricular reserve merit further investigation for patients with this phenotype.

A fast computational model for circulatory dynamics: effects of left ventricle-aorta coupling

The course of diseases such as hypertension, systolic heart failure and heart failure with a preserved ejection fraction is affected by interactions between the left ventricle (LV) and the vasculature. To study these interactions, a computationally efficient, biophysically based mathematical model for the circulatory system is presented. In a four-chamber model of the heart, the LV is represented by a previously described low-order, wall volume-preserving model that includes torsion and base-to-apex and circumferential wall shortening and lengthening, and the other chambers are represented using spherical geometries. Active and passive myocardial mechanics of all four chambers are included. The cardiac model is coupled with a wave propagation model for the aorta and a closed lumped-parameter circulation model. Parameters for the normal heart and aorta are determined by fitting to experimental data. Changes in the timing and magnitude of pulse wave reflections by the aorta are demonstrated with changes in compliance and taper of the aorta as seen in aging (decreased compliance, increased diameter and length), and resulting effects on LV pressure-volume loops and LV fiber stress and sarcomere shortening are predicted. Effects of aging of the aorta combined with reduced LV contractile force (failing heart) are examined. In the failing heart, changes in aortic properties with aging affect stroke volume and sarcomere shortening without appreciable augmentation of aortic pressure, and the reflected pressure wave contributes an increased proportion of aortic pressure.

The Role of the Vasculature in Heart Failure

The contribution of the vasculature in the development and progression of heart failure (HF) syndromes is poorly understood and often neglected. Incorporating both arterial and venous systems, the vasculature plays a significant role in the regulation of blood flow throughout the body in meeting its metabolic requirements. A deterioration or imbalance between the cardiac and vascular interaction can precipitate acute decompensated HF in both preserved and reduced ejection fraction phenotypes. This is characterised by the increasingly recognised concept of ventricular-arterial coupling: a well-balanced relationship between ventricular and vascular stiffness, which has major implications in HF. Often, the cause of decompensation is unknown, with international guidelines mainly centred on arrhythmia, infection, acute coronary syndrome and its mechanical complications as common causes of decompensation; the vascular component is often underrecognised. A better understanding of the vascular contribution in cardiovascular failure can improve risk stratification, earlier diagnosis and facilitate earlier optimal treatment. This review focuses on the role of the vasculature by integrating the concepts of ventricular-arterial coupling, arterial stiffness and venous return in a failing heart.

A Doppler-exclusive non-invasive computational diagnostic framework for personalized transcatheter aortic valve replacement

Given the associated risks with transcatheter aortic valve replacement (TAVR), it is crucial to determine how the implant will affect the valve dynamics and cardiac function, and if TAVR will improve or worsen the outcome of the patient. Effective treatment strategies, indeed, rely heavily on the complete understanding of the valve dynamics. We developed an innovative Doppler-exclusive non-invasive computational framework that can function as a diagnostic tool to assess valve dynamics in patients with aortic stenosis in both pre- and post-TAVR status. Clinical Doppler pressure was reduced by TAVR (52.2 ± 20.4 vs. 17.3 ± 13.8 [mmHg], p < 0.001), but it was not always accompanied by improvements in valve dynamics and left ventricle (LV) hemodynamics metrics. TAVR had no effect on LV workload in 4 patients, and LV workload post-TAVR significantly rose in 4 other patients. Despite the group level improvements in maximum LV pressure (166.4 ± 32.2 vs 131.4 ± 16.9 [mmHg], p < 0.05), only 5 of the 12 patients (41%) had a decrease in LV pressure. Moreover, TAVR did not always improve valve dynamics. TAVR did not necessarily result in a decrease (in 9 out of 12 patients investigated in this study) in major principal stress on the aortic valve leaflets which is one of the main contributors in valve degeneration and, consequently, failure of heart valves. Diastolic stresses increased significantly post-TAVR (34%, 109% and 81%, p < 0.001) for each left, right and non-coronary leaflets respectively. Moreover, we quantified the stiffness and material properties of aortic valve leaflets which correspond with the reduced calcified region average stiffness among leaflets (66%, 74% and 62%; p < 0.001; N = 12). Valve dynamics post-intervention should be quantified and monitored to ensure the improvement of patient conditions and prevent any further complications. Improper evaluation of biomechanical valve features pre-intervention as well as post-intervention may result in harmful effects post-TAVR in patients including paravalvular leaks, valve degeneration, failure of TAVR and heart failure.

Left ventricular adaptation to aortic regurgitation in adults with repaired coarctation of aorta

BACKGROUND

Aortic regurgitation (AR) can develop in adults with repaired coarctation of aorta (COA), but there are limited data about left ventricular (LV) remodeling and clinical outcomes in this population. The purpose of the study was to compare LV remodeling (LV mass index [LVMI], LV ejection fraction [LVEF], and septal E/e') and onset of symptoms before aortic valve replacement, and LV reverse remodeling (%-change in LVMI, LVEF and E/e') after aortic valve replacement in patients with versus without repaired COA presenting with AR.

METHODS

Asymptomatic adults with repaired COA presenting with moderate/severe AR (AR-COA group) were matched 1:2 to asymptomatic adults without COA and similar severity of AR (control group).

RESULTS

Although both groups (AR-COA n = 52, and control n = 104) had similar age, sex, body mass index, aortic valve gradient, and AR severity, the AR-COA group had higher LVMI (124 ± 28 versus 102 ± 25 g/m², p < 0.001) and E/e' (12.3 ± 2.3 versus 9.5 ± 2.1, p = 0.02) but similar LVEF (63 ± 9% versus 67 ± 10%, p = 0.4). COA diagnosis (adjusted HR 1.95, 95%CI 1.49-2.37, p < 0.001), older age, E/e', and LV hypertrophy were associated with onset of symptoms. Of 89 patients (AR-COA n = 41, and control n = 48) with echocardiographic data at 1-year post- aortic valve replacement, the AR-COA group had less regression of LVMI (-8% [95%CI -5 to -11] versus -17% [95%CI -15 to -21], p < 0.001) and E/e' (-5% [95% CI -3 to -7] versus -16% [95% CI -13 to -19], p < 0.001).

CONCLUSIONS

Patients with COA and AR had a more aggressive clinical course, and perhaps may require a different threshold for surgical intervention.

An ultrasound-exclusive non-invasive computational diagnostic framework for personalized cardiology of aortic valve stenosis

Aortic stenosis (AS) is an acute and chronic cardiovascular disease and If left untreated, 50% of these patients will die within two years of developing symptoms. AS is characterized as the stiffening of the aortic valve leaflets which restricts their motion and prevents the proper opening under transvalvular pressure. Assessments of the valve dynamics, if available, would provide valuable information about the patient's state of cardiac deterioration as well as heart recovery and can have incredible impacts on patient care, planning interventions and making critical clinical decisions with life-threatening risks. Despite remarkable advancements in medical imaging, there are no clinical tools available to quantify valve dynamics invasively or noninvasively. In this study, we developed a highly innovative ultrasound-based non-invasive computational framework that can function as a diagnostic tool to assess valve dynamics (e.g. transient 3-D distribution of stress and displacement, 3-D deformed shape of leaflets, geometric orifice area and angular positions of leaflets) for patients with AS at no risk to the patients. Such a diagnostic tool considers the local valve dynamics and the global circulatory system to provide a platform for testing the intervention scenarios and evaluating their effects. We used clinical data of 12 patients with AS not only to validate the proposed framework but also to demonstrate its diagnostic abilities by providing novel analyses and interpretations of clinical data in both pre and post intervention states. We used transthoracic echocardiogram (TTE) data for the developments and transesophageal echocardiography (TEE) data for validation.

Change in Systemic Arterial Pulsatility Index (SAPi) during Heart Failure Hospitalization is Associated with Improved Outcomes

Study Objective

To identify Change in Systemic Arterial Pulsatitlity index (ΔSAPi) as a novel hemodynamic marker associated with outcomes in heart failure (HF).

Design

The ESCAPE trial was a randomized controlled trial.

Setting

The ESCAPE trial was conducted at 26 sites.

Participants

134 patients were analyzed (mean age 56.8 ± 13.4 years, 29% female).

Interventions

We evaluated the change in SAPi, ([systemic pulse pressure/pulmonary artery wedge pressure) obtained at baseline and at the final hemodynamic measurement in the ESCAPE trial.

Main Outcome Measures

Change in SAPi, (ΔSAPi), was analyzed for the primary outcomes of death, heart transplant, left ventricular assist device (DTxLVAD) or hospitalization, (DTxLVADHF) and secondary outcome of DTxLVAD using Cox proportional hazards regression.

Results

Median change in SAPi was 0.81 (IQR 0.20-1.68). ΔSAPi in uppermost quartile was associated with reductions in DTxLVADHF (HR 0.55 [95% CI 0.32, 0.93]). ΔSAPi in the uppermost and lowermost quartiles combined was similarly associated with significant reductions in DTxLVADHF (HR 0.62 [95% CI 0.41, 0.94]). ΔSAPi higher than 1.17 was associated with improved DTxLVADHF. ΔSAPi was also associated with troponin levels at discharge (regression coefficient p = 0.001) and trended with 6-minute walk at discharge (Spearman correlation r = 0.179, p = 0.058).

Conclusion

ΔSAPi was strongly associated with improved HF clinical profile and adverse outcomes. These findings support further exploration of Δ SAPi in the risk stratification of HF.

The Effect of Ascending Aortic Repair on Left Ventricular Remodeling

Left ventricular (LV) hypertrophy is common in patients with thoracic aortic diseases and is associated with increased long-term mortality. Thoracic aortic aneurysms are reported to increase LV afterload because of kinetic energy loss within the aneurysm sac, which may improve after surgical repair. However, LV afterload may also increase because of the stiffness of prosthetics used for aortic repair. We sought to investigate the long-term effect of surgical aortic repair with prostheses on postsurgical LV mass. We reviewed patients who underwent ascending aortic replacement with a prosthesis at our institution from January 2008 to December 2018. We calculated the LV mass index based on pre- and postoperative echocardiogram measurements. The primary outcome was the change in LV mass index 6 months after aortic repair. Patients aged <18 years and those who had concomitant cardiac operations, severe aortic valve disease, or who had no echocardiographic data were excluded. Of 1,008 patients who underwent ascending aortic replacement, 134 (51 with acute aortic dissections) were included. The median baseline and follow-up LV mass index were 107 (90 to 135) g/m² and 101 (83 to 123) g/m², respectively. Overall, there was a significant reduction of LV mass index over time (p = 0.03). LV mass index decreased in 77 patients (59%). Presentation due to acute aortic dissection (p = 0.03) and baseline LV mass index (p <0.001) were significant predictors of LV mass reduction. In conclusion, LV mass index may significantly decrease over time after the aortic repair, but the course is highly variable. The largest decrease occurred in patients who presented because of aortic dissections rather than for elective repair of aneurysms.

Blood Pressure Variability and Heart Failure Hospitalization: Results From the Women's Health Initiative

INTRODUCTION

Little is known about the relationships between annual visit-to-visit blood pressure variability and heart failure subphenotypes. The aim of this analysis was to examine the association between blood pressure variability and incident heart failure with preserved and reduced ejection fraction.

METHODS

Data from 23,918 postmenopausal women enrolled in the Women's Health Initiative Hormone Therapy Trials were analyzed. Blood pressure was measured at baseline (1993‒1998) and then annually through 2005. Variability was defined as the SD of the mean blood pressure across visits or the SD of the participant's regression line for blood pressure across visits. The outcome was the first heart failure hospitalization. Heart failure ascertainment and adjudications were through March 31, 2018.

RESULTS

During a mean follow-up of 15.8 years, 913 incident cases of heart failure with preserved ejection fraction and 421 cases of heart failure with reduced ejection fraction were identified. In fully adjusted models, including mean longitudinal systolic and diastolic blood pressure and time-varying coronary events interim to heart failure hospitalization, women in the highest versus in the lowest quartile of SD of the mean systolic blood pressure were at a statistically significantly higher risk of heart failure with preserved ejection fraction (hazard ratio [95% CI]=1.61 [1.12, 2.31]) but not of heart failure with reduced ejection fraction (1.18 [0.70,1.96]). Conversely, the hazard ratio (95% CI) for the highest versus lowest quartile of SD of the mean diastolic blood pressure was 1.56 (0.89, 2.74) for heart failure with reduced ejection fraction and 1.19 (0.85,1.65) for heart failure with preserved ejection fraction. Results attenuated for SD of the participant's regression line when additionally adjusted for the temporal trend of systolic and diastolic blood pressure.

CONCLUSIONS

Greater systolic blood pressure variability was associated with a higher risk of heart failure with preserved ejection fraction independent of mean blood pressure and coronary events interim to heart failure hospitalization.

Time-sensitive prognostic performance of an afterload-integrated diastolic index in heart failure with preserved ejection fraction: a prospective multicentre observational study

OBJECTIVES

The prognostic significance of an afterload-integrated diastolic index, the ratio of diastolic elastance (Ed) to arterial elastance (Ea) (Ed/Ea=[E/e']/[0.9×systolic blood pressure]), is valid for 1 year after discharge in older patients with heart failure with preserved ejection fraction (HFpEF). We aimed to clarify the association with changes in Ed/Ea from enrolment to 1 year and prognosis thereafter in patients with HFpEF.

SETTING

A prospective, multicentre observational registry of collaborating hospitals in Osaka, Japan.

PARTICIPANTS

We enrolled 659 patients with HFpEF hospitalised for acute decompensated heart failure (men/women: 296/363). Blood tests and transthoracic echocardiography were performed before discharge and at 1 year after.

PRIMARY OUTCOME MEASURES

All-cause mortality and/or re-admission for heart failure were evaluated after discharge.

RESULTS

High Ed/Ea assessed before discharge was a significant prognostic factor during the first, but not the second, year after discharge in all-cause mortality or all-cause mortality and/or re-admission for heart failure. When re-analysis was performed using the value of Ed/Ea at 1 year after discharge, high Ed/Ea was significant for the prognosis during the second year for both end points (p=0.012 and p=0.033, respectively). The poorest mortality during 1‒2 years after enrolment was observed in those who showed a worsening Ed/Ea during the first year associated with larger left ventricular mass index and reduced left ventricular ejection fraction. In all-cause mortality and/or re-admission for heart failure, the event rate during 1‒2 years was highest in those with persistently high Ed/Ea even after 1 year.

CONCLUSIONS

Time-sensitive prognostic performance of Ed/Ea, an afterload-integrated diastolic index, was observed in older patients with HFpEF.

TRIAL REGISTRATION NUMBER

UMIN000021831.

N-terminal pro-brain natriuretic peptide predicts hospitalization for ischemic stroke in Japanese hemodialysis patients

BACKGROUND

The association between N-terminal pro-brain natriuretic peptide (NT-proBNP) and stroke in Japanese hemodialysis (HD) outpatients is unclear. Therefore, in this study, we investigate whether high NT-proBNP levels are associated with future stroke events in this population.

METHODS

This was a multicenter prospective observational study with post hoc analysis. Baseline NT-proBNP levels were measured at the first HD session of the week and classified into tertiles (first tertile: < 2255 pg/mL; second tertile: ≥ 2255 and < 5657 pg/mL; third tertile: ≥ 5657 pg/mL). Overall hospitalization-free survival rates were compared using the Kaplan-Meier method. The association between NT-proBNP level and hospitalization for stroke was assessed using the multivariate Cox proportional hazards models.

RESULTS

During a 5-year follow-up of 1,229 patients, 103 (8.4%) were hospitalized and 23 (1.9%) died from stroke. The hospitalization-free survival rate for ischemic stroke was lowest in the third tertile (P < 0.01). The crude hazard ratio (HR) of hospitalization was higher in the third tertile compared with the first tertile for both ischemic stroke (HR: 3.92; 95% confidence interval [CI] 2.08-7.37; P < 0.01) and hemorrhagic stroke (HR: 3.75; 95% CI 1.35-10.43; P = 0.01). On multivariate Cox hazard analysis, the adjusted HRs for ischemic stroke were higher in the third tertile. The hospitalization-free survival rates for hemorrhagic stroke and the adjusted HRs did not differ significantly.

CONCLUSIONS

Elevated NT-proBNP level was associated with hospitalization for ischemic stroke, suggesting that NT-proBNP level is a valid biomarker for predicting hospitalization for ischemic stroke in HD outpatients.

Current Understanding of Molecular Pathophysiology of Heart Failure With Preserved Ejection Fraction

Heart Failure (HF) is the most common cause of hospitalization in the Western societies. HF is a heterogeneous and complex syndrome that may result from any dysfunction of systolic or diastolic capacity. Abnormal diastolic left ventricular function with impaired relaxation and increased diastolic stiffness is characteristic of heart failure with preserved ejection fraction (HFpEF). HFpEF accounts for more than 50% of all cases of HF. The prevalence increases with age: from around 1% for those aged <55 years to >10% in those aged 70 years or over. Nearly 50% of HF patients have HFrEF and the other 50% have HFpEF/HFmrEF, mainly based on studies in hospitalized patients. The ESC Long-Term Registry, in the outpatient setting, reports that 60% have HFrEF, 24% have HFmrEF, and 16% have HFpEF. To some extent, more than 50% of HF patients are female. HFpEF is closely associated with co-morbidities, age, and gender. Epidemiological evidence suggests that HFpEF is highly represented in older obese women and proposed as 'obese female HFpEF phenotype'. While HFrEF phenotype is more a male phenotype. In addition, metabolic abnormalities and hemodynamic perturbations in obese HFpEF patients appear to have a greater impact in women then in men (Sorimachi et al., European J of Heart Fail, 2022, 22). To date, numerous clinical trials of HFpEF treatments have produced disappointing results. This outcome suggests that a "one size fits all" approach to HFpEF may be inappropriate and supports the use of tailored, personalized therapeutic strategies with specific treatments for distinct HFpEF phenotypes. The most important mediators of diastolic stiffness are the cardiomyocytes, endothelial cells, and extracellular matrix (ECM). The complex physiological signal transduction networks that respond to the dual challenges of inflammatory and oxidative stress are major factors that promote the development of HFpEF pathologies. These signalling networks contribute to the development of the diseases. Inhibition and/or attenuation of these signalling networks also delays the onset of disease. In this review, we discuss the molecular mechanisms associated with the physiological responses to inflammation and oxidative stress and emphasize the nature of the contribution of most important cells to the development of HFpEF via increased inflammation and oxidative stress.

Reduced Proteolytic Cleavage of von Willebrand Factor Leads to Aortic Valve Stenosis and Load-Dependent Ventricular Remodeling

We hypothesized that excess endothelial-associated von Willebrand factor (vWF) and secondary platelet adhesion contribute to aortic valve stenosis (AS). We studied hyperlipidemic mice lacking ADAMTS13 (LDLR ^-/- AD13 ^-/- ), which cleaves endothelial-associated vWF multimers. On echocardiography and molecular imaging, LDLR ^-/- AD13 ^-/- compared with control strains had increased aortic endothelial vWF and platelet adhesion and developed hemodynamically significant AS, arterial stiffening, high valvulo-aortic impedance, and secondary load-dependent reduction in LV systolic function. Histology revealed leaflet thickening and calcification with valve interstitial cell myofibroblastic and osteogenic transformation, and evidence for TGFβ1 pathway activation. We conclude that valve leaflet endothelial vWF-platelet interactions promote AS through juxtacrine platelet signaling.

Heart Failure With Preserved Ejection Fraction: Heterogeneous Syndrome, Diverse Preclinical Models

Heart failure with preserved ejection fraction (HFpEF) represents one of the greatest challenges facing cardiovascular medicine today. Despite being the most common form of heart failure worldwide, there has been limited success in developing therapeutics for this syndrome. This is largely due to our incomplete understanding of the biology driving its systemic pathophysiology and the heterogeneity of clinical phenotypes, which are increasingly being recognized as distinct HFpEF phenogroups. Development of efficacious therapeutics fundamentally relies on robust preclinical models that not only faithfully recapitulate key features of the clinical syndrome but also enable rigorous investigation of putative mechanisms of disease in the context of clinically relevant phenotypes. In this review, we propose a preclinical research strategy that is conceptually grounded in model diversification and aims to better align with our evolving understanding of the heterogeneity of clinical HFpEF. Although heterogeneity is often viewed as a major obstacle in preclinical HFpEF research, we challenge this notion and argue that embracing it may be the key to demystifying its pathobiology. Here, we first provide an overarching guideline for developing HFpEF models through a stepwise approach of comprehensive cardiac and extra-cardiac phenotyping. We then present an overview of currently available models, focused on the 3 leading phenogroups, which are primarily based on aging, cardiometabolic stress, and chronic hypertension. We discuss how well these models reflect their clinically relevant phenogroup and highlight some of the more recent mechanistic insights they are providing into the complex pathophysiology underlying HFpEF.

Non-invasive quantification of pressure-volume loops in patients with Fontan circulation

Background

Pressure–volume (PV) loops provide comprehensive information of cardiac function, but commonly implies an invasive procedure under general anesthesia. A novel technique has made it possible to non-invasively estimate PV loops with cardiac magnetic resonance (CMR) and brachial pressure which would enable good volume estimation of often anatomically complex ventricles without the need of anesthesia in most cases. In this study we aimed to compare how hemodynamic parameters derived from PV loops in patients with Fontan circulation differ to controls.

Methods

Patients with Fontan circulation (n = 17, median age 12 years, IQR 6–15) and healthy controls (n = 17, 14 years, IQR 13–22) were examined with CMR. Short axis balanced steady-state free-precession cine images covering the entire heart were acquired. PV loops were derived from left ventricular volumes in all timeframes and brachial blood pressure from cuff sphygmomanometry.

Results

Fontan patients had lower stroke work, ventricular mechanical efficiency and external power compared to controls. Fontan patients with dominant right ventricle had higher potential energy indexed to body surface area but lower contractility (Ees) compared to controls. Fontan patients had higher arterial elastance (Ea) and Ea/Ees ratio than controls. Contractility showed no correlation with ejection fraction (EF) in Fontan patients irrespective of ventricular morphology. No difference was seen in energy per ejected volume between Fontan patients and controls.

Conclusions

This non-invasive PV-loop method could be used in future studies to show the potential prognostic value of these measures and if changes in ventricular function over time can be detected earlier by this method compared to changes in ventricular volumes and EF. In contrast to patients with acquired heart failure, Fontan patients had similar energy per ejected volume as controls which suggests similar ventricular oxygen consumption to deliver the same volume in Fontan patients as in controls.

A novel cardiovascular systems model to quantify drugs effects on the inter‐relationship between contractility and other hemodynamic variables

The use of systems‐based pharmacological modeling approaches to characterize mode‐of‐action and concentration‐effect relationships for drugs on specific hemodynamic variables has been demonstrated. Here, we (i) expand a previously developed hemodynamic system model through integration of cardiac output (CO) with contractility (CTR) using pressure‐volume loop theory, and (ii) evaluate the contribution of CO data for identification of system‐specific parameters, using atenolol as proof‐of‐concept drug. Previously collected experimental data was used to develop the systems model, and included measurements for heart rate (HR), CO, mean arterial pressure (MAP), and CTR after administration of atenolol (0.3–30 mg/kg) from three in vivo telemetry studies in conscious Beagle dogs. The developed cardiovascular (CVS)‐contractility systems model adequately described the effect of atenolol on HR, CO, dP/dtmax, and MAP dynamics and allowed identification of both system‐ and drug‐specific parameters with good precision. Model parameters were structurally identifiable, and the true mode of action can be identified properly. Omission of CO data did not lead to a significant change in parameter estimates compared to a model that included CO data. The newly developed CVS‐contractility systems model characterizes short‐term drug effects on CTR, CO, and other hemodynamic variables in an integrated and quantitative manner. When the baseline value of total peripheral resistance is predefined, CO data was not required to identify drug‐ and system‐specific parameters. Confirmation of the consistency of system‐specific parameters via inclusion of data for additional drugs and species is warranted. Ultimately, the developed model has the potential to be of relevance to support translational CVS safety studies.

Hemodynamic Changes During Physiological and Pharmacological Stress Testing in Patients With Heart Failure: A Systematic Review and Meta-Analysis

Although disease etiologies differ, heart failure patients with preserved and reduced ejection fraction (HFpEF and HFrEF, respectively) both present with clinical symptoms when under stress and impaired exercise capacity. The extent to which the adaptation of heart rate (HR), stroke volume (SV), and cardiac output (CO) under stress conditions is altered can be quantified by stress testing in conjunction with imaging methods and may help to detect the diminishment in a patient’s condition early. The aim of this meta-analysis was to quantify hemodynamic changes during physiological and pharmacological stress testing in patients with HF. A systematic literature search (PROSPERO 2020:CRD42020161212) in MEDLINE was conducted to assess hemodynamic changes under dynamic and pharmacological stress testing at different stress intensities in HFpEF and HFrEF patients. Pooled mean changes were estimated using a random effects model. Altogether, 140 study arms with 7,248 exercise tests were analyzed. High-intensity dynamic stress testing represented 73% of these data (70 study arms with 5,318 exercise tests), where: HR increased by 45.69 bpm (95% CI 44.51–46.88; I2 = 98.4%), SV by 13.49 ml (95% CI 6.87–20.10; I2 = 68.5%), and CO by 3.41 L/min (95% CI 2.86–3.95; I2 = 86.3%). No significant differences between HFrEF and HFpEF groups were found. Despite the limited availability of comparative studies, these reference values can help to estimate the expected hemodynamic responses in patients with HF. No differences in chronotropic reactions, changes in SV, or CO were found between HFrEF and HFpEF. When compared to healthy individuals, exercise tolerance, as well as associated HR and CO changes under moderate-high dynamic stress, was substantially impaired in both HF groups. This may contribute to a better disease understanding, future study planning, and patient-specific predictive models.

Systematic Review Registration

[https://www.crd.york.ac.uk/prospero/], identifier [CRD42020161212].

Ventricular-Vascular Uncoupling in Heart Failure: Effects of Arterial Baroreflex-Induced Sympathoexcitation at Rest and During Exercise

Autonomic alterations in blood pressure are primarily a result of arterial baroreflex modulation of systemic vascular resistance and cardiac output on a beat-by-beat basis. The combined central and peripheral control by the baroreflex likely acts to maintain efficient energy transfer from the heart to the systemic vasculature; termed ventricular-vascular coupling. This level of control is maintained whether at rest or during exercise in healthy subjects. During heart failure, the ventricular-vascular relationship is uncoupled and baroreflex dysfunction is apparent. We investigated if baroreflex dysfunction in heart failure exacerbated ventricular-vascular uncoupling at rest, and during exercise in response to baroreceptor unloading by performing bilateral carotid occlusions in chronically instrumented conscious canines. We observed in healthy subjects that baroreceptor unloading caused significant increases in effective arterial elastance (Ea) at rest (1.2 ± 0.3 mmHg/ml) and during exercise (1.3 ± 0.2 mmHg/ml) that coincided with significant increases in stroke work (SW) (1.5 ± 0.2 mmHg/ml) and (1.6 ± 0.2 mmHg/ml) suggesting maintained ventricular-vascular coupling. Heart Failure significantly increased the effect of baroreceptor unloading on Ea at rest (3.1 ± 0.7 mmHg/ml) and during exercise (2.3 ± 0.5 mmHg/ml) whereas no significant increases in stroke work occurred, thus signifying further ventricular-vascular uncoupling. We believe that the enhanced ventricular-vascular uncoupling observed during baroreceptor unloading only worsens the already challenged orthostatic and exercise tolerance and thereby contributes to poor exercise performance and quality of life for heart failure patients.

Hypertension and Ventricular-Arterial Uncoupling in Collegiate American Football Athletes

Background

Ventricular–arterial (VA) coupling is defined as the ratio between arterial elastance (EA) and left ventricular elastance (ELV). VA uncoupling, as occurs in hypertensive heart disease, is associated with adverse outcomes. This study sought to determine the relationship between American football (AF)–associated hypertension and VA uncoupling.

Methods and Results

This was a multicenter, longitudinal, and repeated measures observational study of collegiate AF athletes across 3 years of AF participation. Of 200 freshman athletes initially enrolled, 142 (67 Black [47%]/75 White [53%], 58 linemen [41%]/84 nonlinemen [59%]) were prospectively studied with echocardiography and applanation tonometry. Primary echocardiographic VA coupling outcome measures were EA/ELV and ΔEA/ELV, with increased EA/ELV indicating VA uncoupling. Adjusting for race and player position, AF athletes demonstrated increased EA/ELV (mean [95% CI]Δ, 0.10 [0.04–0.15]; P=0.001) and systolic blood pressure (SBP) (mean [95% CI]Δ, 11.4 [8.3–14.5] mm Hg, P<0.001) over their collegiate AF careers. In combination with longitudinal VA uncoupling, hypertension prevalence (including both stage 1 and 2) increased from 54% at baseline to 77% (44% stage 2) at the end of the study period (P<0.001). In multivariable mixed‐effects linear regression analysis, higher SBP (β=0.021, P=0.02), lower E′ (β=−0.010, P=0.03), and worse global longitudinal strain (β=0.036, P<0.001) were associated with higher EA/ELV. Increased SBP (ΔSBP, β=0.029, P=0.02) and worsened global longitudinal strain (Δglobal longitudinal strain, β=0.045, P<0.001) also predicted increased ΔEA/ELV.

Conclusions

VA uncoupling is associated with pathologically increased SBP and subclinical impairments in left ventricular systolic function in collegiate AF athletes, indicating a key mechanism underlying maladaptive cardiovascular phenotypes observed in this population. Future studies analyzing whether targeted clinical interventions improve VA coupling and health outcomes are warranted.

Cardiac Power Output Is Independently and Incrementally Associated With Adverse Outcomes in Heart Failure With Preserved Ejection Fraction

BACKGROUND

Cardiac power output is a measure of cardiac performance, and its prognostic significance has been shown in heart failure (HF) with reduced ejection fraction. Patients with HF with preserved ejection fraction may have altered cardiac performance, but the prognostic relevance of cardiac power output is unknown. This study sought to determine the association between cardiac power output and clinical outcomes in HF with preserved ejection fraction and to compare its prognostic effect to other measures of cardiac performance including ventricular-arterial coupling and mechanical efficiency.

METHODS

Cardiac power output normalized to left ventricular mass was assessed by echocardiography in 408 patients with HF with preserved ejection fraction. Load-independent contractility (end-systolic elastance), arterial elastance, its coupling (arterial elastance/end-systolic elastance), left ventricular global longitudinal strain, and mechanical efficiency (stroke work/pressure-volume area) were also estimated noninvasively. The primary end point was a composite of cardiovascular mortality or HF hospitalization.

RESULTS

The primary composite outcome occurred in 84 patients during a median follow-up of 19.4 months. There was a dose-dependent association between cardiac power output and the composite outcomes, in which patients with the lowest tertile of cardiac power output had >3-fold risk than those with the highest tertile (hazard ratio, 3.04 [95% CI, 1.66-5.57]; P=0.0003). In a multivariable model, lower cardiac power output was independently associated with adverse outcomes (hazard ratio, 0.70 per 1 SD [95% CI, 0.49-0.97]; P=0.03). In contrast, left ventricular size, end-systolic elastance, arterial elastance, arterial elastance/end-systolic elastance ratio, and left ventricular mechanical efficiency were not associated with outcomes. Cardiac power output provided an incremental prognostic effect over the model based on clinical (age, gender, diastolic blood pressure, and atrial fibrillation) and echocardiographic markers (left atrial size, pulmonary pressures, global longitudinal strain, and the ratio of early diastolic mitral inflow velocity to early diastolic mitral annular tissue velocity; P=0.03).

CONCLUSIONS

In patients with HF with preserved ejection fraction, cardiac power output was independently and incrementally associated with adverse outcomes whereas other markers of cardiac performance were not.

Matrix Gla Protein Levels Are Associated With Arterial Stiffness and Incident Heart Failure With Preserved Ejection Fraction

OBJECTIVE

Arterial stiffness is a risk factor for cardiovascular disease, including heart failure with preserved ejection fraction (HFpEF). MGP (matrix Gla protein) is implicated in vascular calcification in animal models, and circulating levels of the uncarboxylated, inactive form of MGP (ucMGP) are associated with cardiovascular disease-related and all-cause mortality in human studies. However, the role of MGP in arterial stiffness is uncertain. Approach and Results: We examined the association of ucMGP levels with vascular calcification, arterial stiffness including carotid-femoral pulse wave velocity (PWV), and incident heart failure in community-dwelling adults from the Framingham Heart Study. To further investigate the link between MGP and arterial stiffness, we compared aortic PWV in age- and sex-matched young (4-month-old) and aged (10-month-old) wild-type and Mgp+/- mice. Among 7066 adults, we observed significant associations between higher levels of ucMGP and measures of arterial stiffness, including higher PWV and pulse pressure. Longitudinal analyses demonstrated an association between higher ucMGP levels and future increases in systolic blood pressure and incident HFpEF. Aortic PWV was increased in older, but not young, female Mgp+/- mice compared with wild-type mice, and this augmentation in PWV was associated with increased aortic elastin fiber fragmentation and collagen accumulation.

CONCLUSIONS

This translational study demonstrates an association between ucMGP levels and arterial stiffness and future HFpEF in a large observational study, findings that are substantiated by experimental studies showing that mice with Mgp heterozygosity develop arterial stiffness. Taken together, these complementary study designs suggest a potential role of therapeutically targeting MGP in HFpEF.

Overcoming the Limits of Ejection Fraction and Ventricular-Arterial Coupling in Heart Failure

Left ventricular ejection fraction (LVEF) and ventricular-arterial coupling (VAC) [VAC = Ea/Ees; Ea: effective arterial elastance; Ees: left ventricle (LV) elastance] are both dimensionless ratios with important limitations, especially in heart failure setting. The LVEF to VAC relationship is a divergent non-linear function, having a point of intersection at the specific value of 0.62, where V0 = 0 ml (V0: the theoretical extrapolated value of the volume-axis intercept at end-systolic pressure 0 mmHg). For the dilated LV, both LVEF and VAC are highly dependent on V0 which is inconclusive when derived from single-beat Ees formulas. VAC simplification should be avoided. Revisiting the relationship between systolic time intervals (STI), pressure, and volumes could provide simple-to-use guiding formulas, affordable for daily clinical practice. We have analyzed by echocardiography the hemodynamics of 21 patients with severe symptomatic heart failure with reduced ejection (HFrEF) compared to 12 asymptomatic patients (at risk of heart failure with mild structural disease). The groups were unequivocally separated by ‘classic’ measures (LVEF, LV end-systolic volume (ESV), LV mass, STI). Chen's Ees formula was weakly correlated with LVEF and indexed ESV (ESVi) but better correlated to the pre-ejection period (PEP); PEP/total ejection time (PEP/TET); systolic blood pressure/PEP (SBP/PEP) (P < 0.001). Combining the predictability of the LVEF to the determinant role of SBP/PEP on the Ees variations, we obtained: (SBP^*LVEF)/PEP mm Hg/ms, with an improved R² value (R² = 0.848; P < 0.001). The strongest correlations to VAC were for LVEF (R = −0.849; R² = 0.722) and PEP/TET (R = 0.925; R² = 0.857). By multiple regression, the VAC was strongly predicted (N = 33): (R = 0.975; R² = 0.95): VAC = 0.553–0.009^*LVEF + 3.463^*PEP/TET, and natural logarithm: Ln (VAC) = 0.147–1.4563^*DBP/SBP^*0.9–0.010^*LVEF + 4.207^*PEP/TET (R = 0.987; R² = 0.975; P = 0) demonstrating its exclusive determinants: LVEF, PEP/TET, and DBP/SBP. Considering Ea as a known value, the VAC-derived Ees formula: Ees_d ≈ Ea/(0.553–0.009^*LVEF+3.463^*PEP/TET) was strongly correlated to Chen's Ees formula (R = 0.973; R² = 0.947) being based on SBP, ESV, LVEF, and PEP/TET and no exponential power. Thus, the new index supports our hypothesis, in the limited sample of patients with HFrEF. Indices like SBP/PEP, (SBP^*LVEF)/PEP, PEP/TET, and DBP/SBP deserve further experiments, underlining the major role of the forgotten STI.

Carotid Atherosclerosis Predicts Blood Pressure Control in Patients With Hypertension: The Campania Salute Network Registry

Background

The 2018 European Society of Cardiology/European Society of Hypertension arterial hypertension guidelines do not recommend routine carotid ultrasound as a tool to identify hypertension‐mediated organ damage, unless clinically indicated. However, carotid plaque (CP) is a strong correlate of increased arterial stiffness, which influences blood pressure (BP) control over time. Thus, we assessed whether evidence of CP at first visit could predict BP control during follow‐up.

Methods and Results

From the CSN (Campania Salute Network) Registry, 6684 patients with hypertension had complete carotid ultrasound examination and were categorized by the presence of CP at baseline. Optimal BP control was defined as average BP <140/90 mm Hg and <135/85 during follow‐up for office and home BP, respectively. At baseline, participants with CP (n=3061) were more likely to be men, to be older, to have diabetes, and to exhibit higher systolic BP, lower diastolic BP, worse lipid profile, and higher prevalence of left ventricular hypertrophy (all P<0.0001) than patients without CP. Optimal office BP control was adjudicated in 54% with and 62% without CP (P<0.0001), and optimal home BP in 51% with and 58% without CP (P<0.01). Presence of CP was significantly associated with the reduced probability of controlled office BP during follow‐up (both P<0.0001), independently of significant effect of older age, male sex, higher baseline BP values, classes of medication, and presence of left ventricular hypertrophy, and only attenuated by duration of hypertension.

Conclusions

Presence of CP in treated patients with hypertension is associated with suboptimal BP control during follow‐up, independently of worse metabolic profile and presence of left ventricular hypertrophy.

Management of hypertension associated with cardiovascular failure

Hypertension (HT) treatment should focus on the prevention of new-onset heart failure (HF) or its exacerbation due to the increasing trend of HF incidence in Japan. According to the SPRINT trial, strict control of blood pressure (BP) of approximately 120 mmHg suppresses the progression of HF stages A and B to a more severe stage. However, in stages C and D, the target value for BP reduction differs depending on whether HF is HF reduced ejection fraction (EF) (HFrEF) or HF preserved EF (HFpEF). Additionally, the relationship between BP control and the prognosis of HF mostly showed the J-curve phenomenon in both HFrEF and HFpEF; however, patients with HFpEF need a lower target BP value than those with HFrEF. One reason is that vascular failure is associated with the pathophysiology of HF. Therefore, it is important to utilize an antihypertensive treatment strategy that considers vascular insufficiency. In addition, the presence or absence of compelling indications is important for the selection of antihypertensive (with cardioprotective effects for HF) medications. The uptitration of cardioprotective medications such as angiotensin-converting enzyme inhibitors/angiotensin II type 1a receptor blockers and beta-blockers is recommended in patients with HFrEF; however, it is often not practically possible to increase the dosage. In these cases, the use of medications in combination with other medication classes is also useful. Moreover, it is also useful to properly use medications of the same class considering their onset of action and half-life in the blood. It is still unclear how cardioprotective medications are used in patients with HFrEF, especially on certain age groups. The optimal initiation and continuation of cardioprotective medications should be carefully determined.

Comparison of the Association Between Arterial Stiffness Indices and Heart Failure in Patients With High Cardiovascular Risk: A Retrospective Study

Objective: Study findings of the relationship of each arterial stiffness index with incident heart failure (HF) are conflicting. We aimed to compare the association between the indices of arterial stiffness and the risk of HF. Methods: We analysed 3,034 patients from a prospective cohort that enrolled patients with high cardiovascular risk. They underwent brachial-ankle pulse wave velocity (baPWV), brachial pulse pressure (PP), carotid-femoral pulse wave velocity (cfPWV), and central PP measurements. Results: Over a median follow-up of 4.7 years (interquartile range, 3.4-5.8 years), 65 HF events occurred. The incidence rate of HF was 4.7 per 1,000 person-years [95% confidence interval (CI), 3.7-6.0]. There was no difference in baPWV in those with and without HF events (1,561 ± 401 and 1,520 ± 321 cm/s, respectively, P = 0.415); however, there was a significant difference in brachial PP (63.2 ± 16.9 vs. 52.3 ± 11.5 mmHg, P < 0.001), cfPWV (11.0 ± 3.1 vs. 9.4 ± 2.4 m/s, P < 0.001) and central PP (56.6 ± 19.9 vs. 42.9 ± 13.8 mmHg, P < 0.001). In the multivariable-adjusted model, brachial PP [hazards ratio (HR) per standard deviation unit (SDU), 1.48; 95% CI, 1.19-1.84, P < 0.001], cfPWV (HR per SDU, 1.29; 95% CI, 1.02-1.63, P = 0.032) and central PP (HR per SDU, 1.44; 95% CI, 1.17-1.78; P < 0.001) were associated with incident HF, but baPWV was not (HR per SDU, 0.83; 95% CI, 0.63-1.10; P = 0.198). In the receiver operating characteristic analysis, the area under the curve (AUC) of brachial PP (P < 0.001), cfPWV (P = 0.003) or central PP (P = 0.001) was larger than that of baPWV, and there was no difference in the AUCs of brachial PP, cfPWV and central PP. Conclusion: Among arterial stiffness indices, brachial PWV was less associated with the risk of heart failure, and brachial PP and measures representing central hemodynamics were highly associated with incident HF.

Short-term ventriculo-arterial coupling and myocardial work efficiency in preterm infants undergoing percutaneous patent ductus arteriosus closure

Definitive closure of a patent ductus arteriosus (PDA) causes significant changes in loading conditions of the left ventricle (LV) which can lead to cardiorespiratory instability including hypotension, low cardiac output, oxygenation, and ventilation impairment. Physiological insights of the adaptation of the LV can be gained by looking at ventriculo-arterial coupling (VAC) and myocardial work-energetics. We conducted a retrospective cohort study of preterm infants with echocardiographic assessment of VAC parameters, including end-systolic and arterial elastance (EES , EA ), and myocardial work indices derived from longitudinal strain analysis before and 1-h after percutaneous PDA closure. A total of 35 patients were included with mean [±SD] age at intervention of 30.8 ± 9.9 days and median [IQR] weight of 1130 [995, 1318] grams. There was a reduction in preload and stroke volume, an increase in EA (38.6 ± 11.4 vs. 60 ± 15.1 mmHg/ml/kg, p < 0.001) and in EES (72 [61.5, 109.8] vs. 91.6 [72.2, 125.2] mmHg/ml/kg, p = 0.003) post-closure. Myocardial work indices reduced after PDA closure, including global work efficiency (93.9 ± 2.3 vs. 91.1 ± 3.6%, p < 0.001). A total of 17 (48.6%) patients developed post-closure instability which was associated with younger age, lower preload, and higher EA and EES . Percutaneous PDA closure is associated with major short-term changes in VAC and myocardium energetics, which may provide novel insights on the physiology of PDA closure and on the differential vulnerability to changes in loading conditions.

Sex differences in cardiovascular adaptations in recreational marathon runners

INTRODUCTION

There are well-established sex differences in central hemodynamic and cardiac adaptations to endurance exercise; however, controversial evidence suggests that excessive endurance exercise may be related to detrimental cardiovascular adaptations in marathoners.

PURPOSE

To examine left ventricle (LV) structure, LV function, 24-h central hemodynamics and ventricular-vascular coupling in male and female marathoners and recreationally active adults.

METHODS

52 marathoners (41 ± 5 years, n = 28 female, completed 6 ± 1 marathons/3 years) and 49 recreationally active controls (42 ± 5 years, n = 25 female) participated in the study. Three-Dimensional Echocardiography (3DE) was used to measure LV mass index and LV longitudinal (LS) circumferential (CS), area (AS), and radial strain (RS). An ambulatory blood pressure (BP) cuff was used to measure 24-h central hemodynamics (BP, pulse wave velocity, PWV, wave reflection index, RIx). Hemodynamic and 3DE measures were combined to derive the ratio of arterial elastance (Ea) to ventricular elastance (Elv) as a global measure of ventricular-vascular coupling.

RESULTS

There were no sex or group differences in LS, CS, AS, and RS (p > 0.05). Females marathoners had similar aortic BP (116 ± 9 vs. 113 ± 1 mmHg), and PWV (5.9 ± 0.5 vs. 5.9 ± 1.1 m/s) compared to female controls but lower aSBP (116 ± 9 vs. 131 ± 10 mmHg) and PWV (5.9 ± 0.5 vs. 6.2 ± 0.5 m/s) compared to male marathoners (p < 0.05). Female marathoners had lower Ea/Elv than female controls (0.67 ± 0.20 vs. 0.93 ± 0.36) and male marathoners (0.67 ± 0.20 vs. 0.85 ± 0.42, p < 0.05).

CONCLUSIONS

Women that have completed multiple marathons do not have reduced LV function or increased aortic stiffness and may have better ventricular-vascular coupling compared to male marathoners and their female untrained counterparts.

Association Between Arterial Stiffness and Heart Failure With Preserved Ejection Fraction

Cardiovascular diseases are the leading cause of mortality in the world. Heart failure with preserved ejection fraction (HFpEF) accounts for about half of all heart failure. Unfortunately, the mechanisms of HFpEF are still unclear, leading to little progress of effective treatment of HFpEF. Arterial stiffness is the decrement of arterial compliance. The media of large arteries degenerate in both physiological and pathological conditions. Many studies have proven that arterial stiffness is an independent risk factor for cardiovascular disorders including diastolic dysfunction. In this perspective, we discussed if arterial stiffness is related to HFpEF, and how does arterial stiffness contribute to HFpEF. Finally, we briefly summarized current treatment strategies on arterial stiffness and HFpEF. Though some new drugs were developed, the safety and effectiveness were not adequately assessed. New pharmacologic treatment for arterial stiffness and HFpEF are urgently needed.

Differential Effect of the Morning Blood Pressure Surge on Prognoses Between Heart Failure With Reduced and Preserved Ejection Fractions

BACKGROUND

Rising blood pressure (BP) in the morning, known as the morning BP surge (MBPS), is known to pose a risk for cardiovascular events in hypertensive individuals. It was not known whether the MBPS was associated with a worse prognosis in patients with heart failure (HF) with a reduced (HFrEF) or preserved (HFpEF) ejection fraction.Methods and Results:We performed a prospective, observational cohort study of hospitalized HF patients who underwent ambulatory BP monitoring (ABPM). The MBPS was calculated by subtracting the mean systolic BP (SBP) during the 1 h that included the lowest sleep BP from the mean SBP during the 2 h after waking. The MBPS group was defined as the top decile of MBPS (>40 mmHg). In all, 456 hospitalized HF patients (mean [±SD] age 68±13 years, 63.9% male) were followed-up for a median of 1.67 years. There were 90 events (16.3 per 100 person-years) of the composite outcome (all-cause mortality and worsening HF) in the HFrEF group, compared with 53 events (19.6 per 100 person-years) in the HFpEF group. Multivariate Cox regression analysis showed that MBPS was a significant predictor of outcome (hazard ratio 2.84, 95% confidence interval 1.58-5.10, P<0.01) in the HFrEF but not HFpEF group.

CONCLUSIONS

MBPS was found to be a novel predictor of worsening HF in patients with HFrEF.

Ventricular-arterial coupling: definition, pathophysiology and therapeutic targets in cardiovascular disease

INTRODUCTION

The heart and arterial system are equally affected by arteriosclerosis/atherosclerosis. There is a constant interaction between the left ventricular (LV) function and the arterial system, termed ventricular-arterial coupling (VAC), which reflects the global cardiovascular efficiency. VAC is traditionally assessed by echocardiography as the ratio of effective arterial elastance (E_a) over end-systolic elastance (E_es) (E_a/E_es). However, the concept of VAC is evolving and new methods have been proposed such as the ratio of pulse wave velocity (PWV) to global longitudinal strain (GLS) and myocardial work index.

AREA COVERED

This clinical review presents the hemodynamic background of VAC, its clinical implications and the impact of therapeutic interventions to normalize VAC. The review also summarizes the detrimental effects of cardio-metabolic risk factors on the aorta and LV, and provides an update on arterial load and its impact on LV function. The narrative review is based upon a systemic search of the bibliographic database PubMed for publications on VAC.

EXPERT OPINION

Newer methods such as PWV/GLS-ratio may be a superior marker of VAC than the traditional echocardiographic E_a/E_es in predicting target organ damage and its association with clinical outcomes. Novel anti-diabetic drugs and optimal antihypertensive treatment may normalize VAC in high-risk patients.

Effects of Choice of Medical Imaging Modalities on a Non-invasive Diagnostic and Monitoring Computational Framework for Patients With Complex Valvular, Vascular, and Ventricular Diseases Who Undergo Transcatheter Aortic Valve Replacement

Due to the high individual differences in the anatomy and pathophysiology of patients, planning individualized treatment requires patient-specific diagnosis. Indeed, hemodynamic quantification can be immensely valuable for accurate diagnosis, however, we still lack precise diagnostic methods for numerous cardiovascular diseases including complex (and mixed) valvular, vascular, and ventricular interactions (C3VI) which is a complicated situation made even more challenging in the face of other cardiovascular pathologies. Transcatheter aortic valve replacement (TAVR) is a new less invasive intervention and is a growing alternative for patients with aortic stenosis. In a recent paper, we developed a non-invasive and Doppler-based diagnostic and monitoring computational mechanics framework for C3VI, called C3VI-DE that uses input parameters measured reliably using Doppler echocardiography. In the present work, we have developed another computational-mechanics framework for C3VI (called C3VI-CT). C3VI-CT uses the same lumped-parameter model core as C3VI-DE but its input parameters are measured using computed tomography and a sphygmomanometer. Both frameworks can quantify: (1) global hemodynamics (metrics of cardiac function); (2) local hemodynamics (metrics of circulatory function). We compared accuracy of the results obtained using C3VI-DE and C3VI-CT against catheterization data (gold standard) using a C3VI dataset (N = 49) for patients with C3VI who undergo TAVR in both pre and post-TAVR with a high variability. Because of the dataset variability and the broad range of diseases that it covers, it enables determining which framework can yield the most accurate results. In contrast with C3VI-CT, C3VI-DE tracks both the cardiac and vascular status and is in great agreement with cardiac catheter data.

Non-invasive quantification of pressure-volume loops from cardiovascular magnetic resonance at rest and during dobutamine stress

Non-invasive quantification of pressure-volume (PV) loops from brachial pressure and cardiovascular magnetic resonance is a validated method but its application has been limited to resting heart rates. The aim of this study was to improve the previous method and validate it against invasive left-ventricular pressure measurements in an experimental porcine model, and further apply it to 16 healthy humans at rest and during dobutamine stress. In addition, the improved method calculates the arterial elastance which provides the computation of the ratio of effective arterial (E_a ) to maximal ventricular elastance (E_max ) representing the ventricular-arterial coupling. In the porcine model, the differences between the improved non-invasively derived PV loops and invasively measured PV loops were for stroke work (mean ± SD) 0.00 ± 0.03 J, ventricular efficiency -1.1 ± 0.4%, and contractility 1.1 ± 0.1 mmHg/ml. In human subjects during dobutamine stress, stroke work increased from 1.3 ± 0.3 to 1.7 ± 0.4 J, ventricular efficiency from 71 ± 4 to 82 ± 4%, contractility from 1.3 ± 0.2 to 2.3 ± 0.6 mmHg/ml, and the ratio of arterial to ventricular elastance decreased from 0.96 to 0.56. The improved method for non-invasive PV loops constitutes a more robust diagnostic tool for cardiac disease states in a wider range of study cohorts at both rest and during stress.