Obesity, venous capacitance, and venous compliance in heart failure with preserved ejection fraction

Exercise Testing in HFpEF: an Appraisal Through Diagnosis, Pathophysiology and Therapy A Clinical Consensus Statement of the Heart Failure Association (HFA) and European Association of Preventive Cardiology (EAPC) of the European Society of Cardiology (ESC)

Patients with heart failure with preserved ejection fraction (HFpEF) universally complain of exercise intolerance and dyspnoea as key clinical correlates. Cardiac as well as extracardiac components play a role for the limited exercise capacity, including an impaired cardiac and peripheral vascular reserve, a limitation in mechanical ventilation and/or gas exchange with reduced pulmonary vascular reserve, skeletal muscle dysfunction and iron deficiency/anaemia. Although most of these components can be differentiated and quantified through gas exchange analysis by cardiopulmonary exercise testing (CPET), the information provided by objective measures of exercise performance have not been systematically considered in the recent algorithms/scores for HFpEF diagnosis, neither by European nor US groups. The current Clinical Consensus Statement by the HFA and EAPC Association of the ESC aims at outlining the role of exercise testing and its pathophysiological, clinical and prognostic insights, addressing the implication of a thorough functional evaluation from the diagnostic algorithm to the pathophysiology and treatment perspectives of HFpEF. Along with these goals, we provide a specific analysis on the evidence that CPET is the standard for assessing, quantifying, and differentiating the origin of dyspnoea and exercise impairment and even more so when combined with echo and/or invasive hemodynamic evaluation is here provided. This will lead to improved quality of diagnosis when applying the proposed scores and may also help useful to implement the progressive characterization of the specific HFpEF phenotypes, a critical step toward the delivery of phenotype-specific treatments.

Diastolic Filling Time, Chronotropic Response, and Exercise Capacity in Heart Failure and Preserved Ejection Fraction With Sinus Rhythm

Background

Exercise‐induced high heart rate may impair exercise tolerance by reducing diastolic filling time and ventricular filling in heart failure with preserved ejection fraction (HFpEF). Given the importance of chronotropic response, we hypothesized that reduction in diastolic filling time because of exercise‐induced increased heart rate would not impair cardiac output reserve and exercise capacity. We sought to determine the association between heart rate, diastolic filling time, hemodynamics, and exercise capacity in HFpEF.

Methods and Results

Patients with HFpEF (n=66) and controls without HF (n=107) underwent bicycle exercise echocardiography with simultaneous expired gas analysis to measure oxygen consumption. Diastolic filling time was assessed by the overlap time between mitral E‐ and A‐waves (longer overlap time indicates shorter diastolic filling duration). Overlap time increased (ie, diastolic filling time shortened) in HFpEF and controls as heart rate increased with exercise, and the relationship was similar between the groups. Greater heart rate response correlated with higher cardiac output (r=0.51, P<0.0001) and oxygen consumption (r=0.50, P<0.0001) during peak exercise. Shorter diastolic filling time, as assessed by longer overlap time, was correlated with higher cardiac output (r=0.47, P<0.0001) and peak oxygen consumption (r=0.38, P=0.007), not with E/e′ or right ventricular‐pulmonary artery uncoupling. Longer overlap time was associated with mitral A velocity (r=0.53, P<0.0001) and left atrial booster pump strain (r=0.42, P<0.0001).

Conclusions

Shortening of diastolic filling interval in tandem with increased heart rate during exercise does not limit cardiac output reserve or exercise capacity in HFpEF.

Recombinant human brain natriuretic peptide ameliorates venous return function in congestive heart failure

Aims

Recombinant human brain natriuretic peptide (rh‐BNP) is commonly used as a decongestive therapy. This study aimed to investigate the instant effects of rh‐BNP on cardiac output and venous return function in post‐cardiotomy patients with congestive heart failure (CHF).

Methods and results

Twenty‐four post‐cardiotomy heart failure patients were enrolled and received a standard loading dose of rh‐BNP. Haemodynamic monitoring was performed via a pulmonary artery catheter before and after the administration of rh‐BNP. The cardiac output and venous return functions were estimated by depicting Frank‐Starling and Guyton curves. After rh‐BNP infusion, variables reflecting cardiac congestion and venous return function, such as pulmonary artery wedge pressure, mean systemic filling pressure (Pmsf) and venous return resistance index (VRRI), reduced from 15 ± 3 to 13 ± 3 mmHg, from 32 ± 7 to 28 ± 7 mmHg and from 6.7 ± 2.6 to 5.7 ± 1.8 mmHg min m²/L, respectively. Meanwhile, cardiac index, stroke volume index, and the cardiac output function curve remained unchanged per se. The decline in Pmsf [−13% (−22% to −8%)] and VRRI [−12% (−25% to −5%)] was much greater than that in the systemic vascular resistance index [−7% (−14% to 0%)]. In the subgroup analysis of reduced ejection fraction (<40%) patients, the aforementioned changes were more significant.

Conclusions

rh‐BNP might ameliorate venous return rather than cardiac output function in post‐cardiotomy CHF patients.

Endovascular Ablation of the Right Greater Splanchnic Nerve in Heart Failure with Preserved Ejection Fraction: Early Results of the REBALANCE-HF Trial Roll-in Cohort

Aims

In heart failure (HF) with preserved ejection fraction (HFpEF), excessive redistribution of blood volume into the central circulation leads to elevations of intracardiac pressures with exercise limitations. Splanchnic ablation for volume management (SAVM) has been proposed as a therapeutic intervention. Here we present preliminary safety and efficacy data from the initial roll‐in cohort of the REBALANCE‐HF trial.

Methods and results

The open‐label (roll‐in) arm of REBALANCE‐HF will enrol up to 30 patients, followed by the randomized, sham‐controlled portion of the trial (up to 80 additional patients). Patients with HF, left ventricular ejection fraction (LVEF) ≥50%, and invasive peak exercise pulmonary capillary wedge pressure (PCWP) ≥25 mmHg underwent SAVM. Baseline and follow‐up assessments included resting and exercise PCWP, New York Heart Association (NYHA) class, Kansas City Cardiomyopathy Questionnaire (KCCQ), 6‐min walk test, and N‐terminal pro‐B‐type natriuretic peptide (NT‐proBNP). Efficacy and safety were assessed at 1 and 3 months. Here we report on the first 18 patients with HFpEF that have been enrolled into the roll‐in, open‐label arm of the study across nine centres; 14 (78%) female; 16 (89%) in NYHA class III; and median (interquartile range) age 75.2 (68.4–81) years, LVEF 61.0 (56.0–63.2)%, and average (standard deviation) 20 W exercise PCWP 36.4 (±8.6) mmHg. All 18 patients were successfully treated. Three non‐serious moderate device/procedure‐related adverse events were reported. At 1‐month, the mean PCWP at 20 W exercise decreased from 36.4 (±8.6) to 28.9 (±7.8) mmHg (p < 0.01), NYHA class improved by at least one class in 33% of patients (p = 0.02) and KCCQ score improved by 22.1 points (95% confidence interval 9.4–34.2) (p < 0.01).

Conclusion

The preliminary open‐label results from the multicentre REBALANCE‐HF roll‐in cohort support the safety and efficacy of SAVM in HFpEF. The findings require confirmation in the ongoing randomized, sham‐controlled portion of the trial.

Venous Tone and Stressed Blood Volume in Heart Failure: JACC Review Topic of the Week

A number of pathologic processes contribute to the elevation in cardiac filling pressures in heart failure (HF), including myocardial dysfunction and primary volume overload. In this review, we discuss the important role of the venous system and the concepts of stressed blood volume and unstressed blood volume. We review how regulation of venous tone modifies the distribution of blood between these 2 functional compartments, the physical distribution of blood between the pulmonary and systemic circulations, and how these relate to the hemodynamic abnormalities observed in HF. Finally, we review recently applied methods for estimating stressed blood volume and how they are being applied to the results of clinical studies to provide new insights into resting and exercise hemodynamics and therapeutics for HF.

Abdominal Obesity Is Associated with an Increased Risk of All-Cause Mortality in Males but Not in Females with HFpEF

Background. Association between abdominal obesity and development of heart failure (HF) with preserved ejection fraction (HFpEF) between the sexes is not completely understood. Objectives. This study evaluated the association between abdominal obesity and the risk of all-cause mortality in patients with HFpEF while performing a gender outcome comparison. Methods. A post hoc analysis was undertaken from the American cohort of the Treatment of Preserved Cardiac Function Heart Failure with an Aldosterone Antagonist (TOPCAT). The primary outcome (all-cause mortality) and the secondary outcomes (cardiovascular mortality, hospitalization for HF, stroke, and MI) were evaluated via Cox proportional hazards models to compare the hazard ratios (HRs) between sexes in HFpEF patients. Abdominal obesity was defined as a waist circumference of ≥102 cm in men and ≥88 cm in women. Results. A total of 3320 HFpEF patients (1620 men [48.80%] and 1700 women [51.20%]) were included in the analysis. The mean follow-up period was $3.4\pm 1.7$ years, with 503 patients dying during that time. After multivariable adjustment, abdominal obesity was significantly associated with an increased risk of all-cause mortality in males (adjusted HR: 1.32; 95% confidence interval [CI]: 1.02 to 1.71; $p=0.038$ ). Abdominal obesity was associated with hospitalization for HF in both male (adjusted HR: 1.39; 95% CI: 1.01 to 1.93; $p=0.045$ ) and female patients (adjusted HR: 1.15; 95% CI: 1.18 to 3.28; $p=0.010$ ). Conclusions. Abdominal obesity is associated with increased risks of all-cause mortality in the male but not the female HFpEF population and is associated with increased risks of hospitalization for HF in both sexes.

Exercise Stress Echocardiography in the Diagnostic Evaluation of Heart Failure with Preserved Ejection Fraction

More than half of patients with heart failure have a preserved ejection fraction (HFpEF). The prevalence of HFpEF has been increasing worldwide and is expected to increase further, making it an important health-care problem. The diagnosis of HFpEF is straightforward in the presence of obvious objective signs of congestion; however, it is challenging in patients presenting with a low degree of congestion because abnormal elevation in intracardiac pressures may occur only during physiological stress conditions, such as during exercise. On the basis of this hemodynamic background, current consensus guidelines have emphasized the importance of exercise stress testing to reveal abnormalities during exercise, and exercise stress echocardiography (i.e., diastolic stress echocardiography) may be used as an initial diagnostic approach to HFpEF owing to its noninvasive nature and wide availability. However, evidence supporting the use of this method remains limited and many knowledge gaps exist with respect to diastolic stress echocardiography. This review summarizes the current understanding of the use of diastolic stress echocardiography in the diagnostic evaluation of HFpEF and discusses its strengths and limitations to encourage future studies on this subject.

Targeting Preload in Heart Failure: Splanchnic Nerve Blockade and Beyond

Preload augmentation represents a critical mechanism for the cardiovascular system to increase effective circulating blood volume to increase cardiac filling pressures and, subsequently, for the heart to increase cardiac output. The splanchnic vascular compartment is the primary source of vascular capacity and thus the primary target for preload recruitment in humans. Under normal conditions, sympathetic stimulation of these primary venous vessels promotes the shift of blood from the splanchnic to the thoracic compartment and elevates preload and cardiac output. However, in heart failure, since filling pressures may be elevated at rest due to decreased venous capacitance, incremental recruitment of preload to enhance cardiac output may exacerbate congestion and limit exercise capacity. Accordingly, recent attention has focused on therapies designed to regulate splanchnic vascular redistribution to improve cardiac filling pressures and patient-centered outcomes such as quality of life and exercise capacity in patients with heart failure. In this review, we discuss the relevance of splanchnic circulation as a venous reservoir, the contribution of stressed blood volume to heart failure pathogenesis, and the implications for pharmacological therapeutic interventions to prevent heart failure decompensation. Further, we review emerging device-based approaches for cardiac preload reduction such as partial/complete occlusion of the superior vena cava or the inferior vena cava.

Heart Failure with Preserved Ejection Fraction: Mechanisms and Treatment Strategies

Approximately half of all patients with heart failure (HF) have a preserved ejection fraction, and the prevalence is growing rapidly given the aging population in many countries and the rising prevalence of obesity, diabetes, and hypertension. Functional capacity and quality of life are severely impaired in heart failure with preserved ejection fraction (HFpEF), and morbidity and mortality are high. In striking contrast to HF with reduced ejection fraction, there are few effective treatments currently identified for HFpEF, and these are limited to decongestion by diuretics, promotion of a healthy active lifestyle, and management of comorbidities. Improved phenotyping of subgroups within the overall HFpEF population might enhance individualization of treatment. This review focuses on the current understanding of the pathophysiologic mechanisms underlying HFpEF and treatment strategies for this complex syndrome.

Hemodynamics for the Heart Failure Clinician: A State-of-the-Art Review

Heart failure (HF) fundamentally reflects an inability of the heart to provide adequate blood flow to the body without incurring the cost of increased cardiac filling pressures. This failure occurs first during the stressed state, but progresses until hemodynamic derangements become apparent at rest. As such, the measurement and interpretation of both resting and stressed hemodynamics serve an integral role in the practice of the HF clinician. In this review, we discuss conceptual and technical best practices in the performance and interpretation of both resting and invasive exercise hemodynamic catheterization, relate important pathophysiologic concepts to clinical care, and discuss updated, evidence-based applications of hemodynamics as they pertain to the full spectrum of HF conditions.

Echocardiography in the diagnostic evaluation and phenotyping of heart failure with preserved ejection fraction

Heart failure with preserved ejection fraction (HFpEF) represents one of the greatest unmet needs in modern cardiology given its diagnostic difficulty and limited therapeutic options. Echocardiography provides valuable information on cardiac structure, function, and hemodynamics and plays a central role in the evaluation of HFpEF. Echocardiography is crucial in identifying HFpEF among patients with dyspnea, especially when overt congestion is absent. The combination of echocardiographic indices of diastolic function, clinical characteristics, and natriuretic peptide tests has been proposed in the diagnostic evaluation of patients with suspected HFpEF. Echocardiography also provides valuable insight into the pathophysiology and underlying phenotypes of HFpEF. Exercise stress echocardiography can also detect abnormalities that develop only during exercise. This may enhance the diagnosis of HFpEF by demonstrating elevation in the left ventricular filling pressure and may have potential for better pathophysiological characterization. This review focuses on the role of echocardiography in the diagnostic evaluation and phenotyping of HFpEF. We also discuss the potential role of exercise stress echocardiography for the diagnosis and disease phenotyping of HFpEF.

Uncoupling between intravascular and distending pressures leads to underestimation of circulatory congestion in obesity

AIMS

Patients with obesity frequently present with dyspnoea. Biomarkers that reflect wall stress are often used to evaluate circulatory congestion and help determine whether dyspnoea is of cardiac causes. Patients with obesity display greater external restraint on the heart, which may alter relationships between intravascular pressures and stress markers.

METHODS AND RESULTS

Subjects with unexplained dyspnoea (n = 212) underwent cardiac catheterization with simultaneous echocardiography. Blood sampling was performed in a subset (n = 58). Relationships between echocardiographic and blood biomarkers of circulatory congestion and directly-measured haemodynamics were compared between participants with severe obesity [body mass index (BMI) ≥35 kg/m² , Group B) and those without (BMI <35 kg/m² , Group A). Circulatory congestion was assessed by pulmonary capillary wedge pressure (PCWP), and vascular distending pressure was assessed by left ventricular transmural pressure (LVTMP). As compared to Group A, participants in Group B displayed higher PCWP relative to N-terminal pro-B-type natriuretic peptide, mid-regional pro-atrial natriuretic peptide (MR-proANP), troponin T, and growth differentiation factor-15 (all p < 0.01). In contrast, the relationships between LVTMP and the biomarkers were superimposable. Echocardiographic biomarkers revealed the same pattern: PCWP was higher for any E/e' ratio in Group B compared to Group A, but the relationship between LVTMP and E/e' was similar. In contrast, levels of C-terminal pro-endothelin-1 and MR-proADM were more robustly correlated with PCWP (r = 0.67 and r = 0.62, both p < 0.0001), with no differential relationship based upon BMI.

CONCLUSIONS

Non-invasive haemodynamic markers underestimate circulatory congestion in patients with obesity, an effect that appears related to uncoupling between cardiac wall stress and intravascular pressures. This may lead to systematic under-recognition of congestion in patients with obesity.

Effect of Empagliflozin on Blood Volume Redistribution in Patients With Chronic Heart Failure and Reduced Ejection Fraction: An Analysis from the Empire HF Randomized Clinical Trial

Background: Stressed blood volume (SBV) is a major determinant of systemic and pulmonary venous pressures which, in turn, determine left and right ventricular fillings and regulates cardiac output via the Frank-Starling mechanism. It is not known whether inhibition of the sodium-glucose cotransporter-2 (SGLT2) favorably affects SBV. We investigated the effect of empagliflozin on estimated stressed blood volume (eSBV) in patients with heart failure andreduced ejection fraction (HFrEF) compared to placebo. Methods: This was a post-hoc analysis of an investigator-initiated, double-blinded, placebo controlled, randomized trial. Seventy patients were assigned to empagliflozin 10 mg or matching placebo once-daily for 12 weeks. Patients underwent right heart catheterization at rest and during exercise at baseline and follow-up. The outcome was change in eSBV after 12 weeks of empagliflozin treatment over the full range of exercise, determined using a recently introduced analytical approach based on invasive hemodynamic assessment. Results: Patients with HFrEF, mean age, 57 years and mean ejection fraction 27 %, with 47 patients (71%) receiving diuretics were randomized. The effect of empagliflozin on eSBV over the full range of exercise loads showed a statistically significant reduction compared with placebo (-198.4 mL, 95%CI: -317.4; -79.3, p=0.001), a 9% decrease. The decrease in eSBV by empagliflozin was significantly correlated with the decrease in PCWP ((R= ̶ 0.33, p<0.0001). The effect of empagliflozin was consistent across subgroup analysis. Conclusions: Empagliflozin treatment significantly reduced stressed blood volume compared with placebo after 12 weeks of treatment in patients with stable chronic HFrEF during sub maximal exercise. Registration: URL: https://www.clinicaltrials.gov, Unique identifier: NCT03198585.