Citations

Approximately 50% of patients with heart failure have preserved ejection fraction. Although a wide variety of conditions cause or contribute to heart failure with preserved ejection fraction, elevated left ventricular filling pressures, particularly during exercise, are common to all causes. Acute elevation in left‐sided filling pressures promotes lung congestion and symptoms of dyspnea, while chronic elevations often lead to pulmonary vascular remodeling, right heart failure, and increased risk of mortality. Pharmacologic therapies, including neurohormonal modulation and drugs that modify the nitric oxide/cyclic GMP‐protein kinase G pathway have thus far been limited in reducing symptoms or improving outcomes in patients with heart failure with preserved ejection fraction. Hence, alternative means of reducing the detrimental rise in left‐sided heart pressures are being explored. One proposed method of achieving this is to create an interatrial shunt, thus unloading the left heart at rest and during exercise. Currently available studies have shown 3‐ to 5‐mm Hg decreases of pulmonary capillary wedge pressure during exercise despite increased workload. The mechanisms underlying the hemodynamic changes are just starting to be understood. In this review we summarize results of recent studies aimed at elucidating the potential mechanisms of improved hemodynamics during exercise tolerance following interatrial shunt implantation and the current interatrial shunt devices under investigation.

Heart failure with preserved ejection fraction (HFpEF), a major public health problem that is rising in prevalence, is associated with high morbidity and mortality and is considered to be the greatest unmet need in cardiovascular medicine today because of a general lack of effective treatments. To address this challenging syndrome, the National Heart, Lung, and Blood Institute convened a working group made up of experts in HFpEF and novel research methodologies to discuss research gaps and to prioritize research directions over the next decade. Here, we summarize the discussion of the working group, followed by key recommendations for future research priorities. There was uniform recognition that HFpEF is a highly integrated, multiorgan, systemic disorder requiring a multipronged investigative approach in both humans and animal models to improve understanding of mechanisms and treatment of HFpEF. It was recognized that advances in the understanding of basic mechanisms and the roles of inflammation, macrovascular and microvascular dysfunction, fibrosis, and tissue remodeling are needed and ideally would be obtained from (1) improved animal models, including large animal models, which incorporate the effects of aging and associated comorbid conditions; (2) repositories of deeply phenotyped physiological data and human tissue, made accessible to researchers to enhance collaboration and research advances; and (3) novel research methods that take advantage of computational advances and multiscale modeling for the analysis of complex, high-density data across multiple domains. The working group emphasized the need for interactions among basic, translational, clinical, and epidemiological scientists and across organ systems and cell types, leveraging different areas or research focus, and between research centers. A network of collaborative centers to accelerate basic, translational, and clinical research of pathobiological mechanisms and treatment strategies in HFpEF was discussed as an example of a strategy to advance research progress. This resource would facilitate comprehensive, deep phenotyping of a multicenter HFpEF patient cohort with standardized protocols and a robust biorepository. The research priorities outlined in this document are meant to stimulate scientific advances in HFpEF by providing a road map for future collaborative investigations among a diverse group of scientists across multiple domains.

Abstract Aims Patient-reported quality of life (QOL) is a highly prognostic and clinically relevant endpoint in patients with heart failure (HF) with preserved ejection fraction (HFpEF). The relationships between QOL and different markers of HF severity remain unclear, particularly as they relate to functional capacity and directly measured activity levels. We hypothesized that QOL would demonstrate a stronger relationship with measures of exercise capacity and adiposity compared to other disease measures. Methods and results This is a secondary analysis of the National Heart, Lung, and Blood Institute-sponsored RELAX, NEAT-HFpEF and INDIE-HFpEF trials to determine the relationships between QOL (assessed by the Kansas City Cardiomyopathy Questionnaire and Minnesota Living with Heart Failure Questionnaire) and different domains reflecting HF severity, including maximal aerobic capacity (peak oxygen consumption), submaximal exercise capacity (6-min walk distance), volume of daily activity (accelerometry), physician-estimated functional class, resting echocardiography, and plasma natriuretic peptide levels. A total of 408 unique patients with chronic HFpEF were split into tertiles of QOL scores defined as QOLworst, QOLintermediate, QOLbest. The QOLworst HFpEF group was youngest, with a higher body mass index, greater prevalence of class II obesity and diabetes, and the lowest N-terminal pro-brain natriuretic peptide (NT-proBNP) levels. After adjustment for age, sex and body mass index, poorer QOL was associated with worse physical capacity and activity levels, assessed by peak oxygen consumption, 6-min walk distance and actigraphy, but was not associated with NT-proBNP or indices from resting echocardiography. QOL was similarly reduced in patients with and without prior HF hospitalization. Conclusions Quality of life in HFpEF is poorest in patients who are young, obese and have diabetes, and is more robustly tied to measures reflecting functional capacity and daily activity levels rather than elevations in NT-proBNP or prior HF hospitalization. These findings have major implications for the understanding of QOL in HFpEF and for the design of future clinical trials targeting symptom improvement in HFpEF. Clinical Trial Registration: RELAX, NCT00763867; NEAT-HFpEF, NCT02053493; INDIE-HFpEF, NCT02742129.

ABSTRACT Aims Left atrial (LA) mechanical function may play a significant role in the development and progression of heart failure with preserved ejection fraction (HFpEF). We performed a systematic review and meta-analysis to evaluate association of impaired LA function with outcomes in HFpEF. Methods and results Multiple databases were searched for original studies measuring different phases of LA function in HFpEF patients. Comparative LA function between HFpEF patients and healthy controls was assessed by pooling weighted mean differences (WMD). Adjusted hazard ratios (HRs) with 95% confidence intervals were pooled to evaluate the prognostic utility of LA function. Twenty-two studies (2 trials, 20 observational) comprising 1974 HFpEF patients and 751 healthy controls were included. HFpEF patients had decreased LA reservoir [WMD = −12.21% (−15.47, −8.95); P < 0.001], LA conduit [WMD = −5.68% (−8.56, −2.79); P < 0.001], and pump [WMD = −11.07% (−14.81, −7.34); P < 0.001] emptying fractions compared with controls. LA reservoir [WMD = −13.38% (−16.07, −10.68); P < 0.001], conduit [WMD = −4.09% (−6.77, −1.42); P = 0.003], and pump [WMD = −3.53% (−4.47, −2.59); P < 0.001] strains were also significantly lower in HFpEF patients. Decreased LA reservoir strain [HR 1.24 (1.02, 1.50); P = 0.03] was significantly associated with risk of composite all-cause mortality or heart failure hospitalization. Conclusions Impaired LA function appears to have diagnostic and prognostic value in HFpEF, but whether indices of LA function truly refine discrimination for diagnosis or prognosis remains to be fully determined. Larger studies are needed to better evaluate associations between LA function and clinical outcomes and the role of LA function as a target for novel HFpEF therapies.

Abstract Aims While right ventricular (RV) dysfunction is associated with worse prognosis in co-morbid pulmonary hypertension and heart failure with preserved ejection fraction (PH-HFpEF), the mechanisms driving RV dysfunction are unclear. We evaluated the extent and clinical correlates of diffuse RV myocardial fibrosis in PH-HFpEF, as measured by cardiovascular magnetic resonance-derived extracellular volume (ECV). Methods and results We prospectively enrolled participants with PH-HFpEF (n = 14), pulmonary arterial hypertension (PAH; n = 13), and controls (n = 8). All participants underwent high-resolution cardiovascular magnetic resonance, and case subjects (PH-HFpEF and PAH) additionally underwent right heart catheterization. T1 mapping was performed using high-resolution modified look-locker inversion recovery with a 1 × 1 mm2 in-plane resolution. RV free wall T1 values were quantified, and ECV was calculated. Participants with PH-HFpEF were older and carried higher rates of hypertension and obstructive sleep apnoea than those with PAH. While RV ECV was similar between PH-HFpEF and PAH (33.1 ± 8.0 vs. 34.0 ± 4.5%; P = 0.57), total pulmonary resistance was lower in PH-HFpEF compared with PAH [PH-HFpEF: 5.68 WU (4.70, 7.66 WU) vs. PAH: 8.59 WU (8.14, 12.57 WU); P = 0.01]. RV ECV in PH-HFpEF was associated with worse indices of RV structure (RV end-diastolic volume: r = 0.67, P = 0.01) and RV function (RV free wall strain: r = 0.59, P = 0.03) but was not associated with RV afterload (total pulmonary resistance: r = 0.08, P = 0.79). Conversely, there was a strong correlation between RV ECV and RV afterload in PAH (r = 0.57, P = 0.04). Conclusions Diffuse RV fibrosis, as measured by ECV, is present in PH-HFpEF and is associated with adverse RV structural and functional remodelling but not degree of pulmonary vasculopathy. In PH-HFpEF, diffuse RV fibrosis may occur out of proportion to the degree of RV afterload.

Background: Unlike heart failure with reduced ejection fraction, there is no approved treatment for heart failure with preserved ejection fraction, the predominant phenotype in women. Therefore, there is a greater heart failure therapeutic deficit in women compared with men. Methods: In a prespecified subgroup analysis, we examined outcomes according to sex in the PARAGON-HF trial (Prospective Comparison of ARNI With ARB Global Outcomes in Heart Failure With Preserved Ejection Fraction), which compared sacubitril-valsartan and valsartan in patients with heart failure with preserved ejection fraction. The primary outcome was a composite of first and recurrent hospitalizations for heart failure and death from cardiovascular causes. We also report secondary efficacy and safety outcomes. Results: Overall, 2479 women (51.7%) and 2317 men (48.3%) were randomized. Women were older and had more obesity, less coronary disease, and lower estimated glomerular filtration rate and NT-proBNP (N-terminal pro–B-type natriuretic peptide) levels than men. For the primary outcome, the rate ratio for sacubitril-valsartan versus valsartan was 0.73 (95% CI, 0.59–0.90) in women and 1.03 (95% CI, 0.84–1.25) in men ( P interaction = 0.017). The benefit from sacubitril-valsartan was attributable to reduction in heart failure hospitalization. The improvement in New York Heart Association class and renal function with sacubitril-valsartan was similar in women and men, whereas the improvement in Kansas City Cardiomyopathy Questionnaire clinical summary score was less in women than in men. The difference in adverse events between sacubitril-valsartan and valsartan was similar in women and men. Conclusions: As compared with valsartan, sacubitril-valsartan seemed to reduce the risk of heart failure hospitalization more in women than in men. Whereas the possible sex-related modification of the effect of treatment has several potential explanations, the present study does not provide a definite mechanistic basis for this finding. Clinical Trial Registration: https://www.clinicaltrials.gov . Unique identifier: NCT01920711.

Background Interatrial shunt device (IASD) effects have been described in patients with heart failure and ejection fractions (EFs) ≥40%. However, baseline characteristics that correlate with greatest hemodynamic effects are unknown. On the basis of fundamental principles, we hypothesized that larger pressure gradients between left and right atria would yield greater shunt flow and greater hemodynamic effects. Methods and Results REDUCE LAP-HF (Reduce Elevated Left Atrial Pressure in Patients With Heart Failure) was a multicenter study that investigated IASD safety and performance. Sixty-four patients with EF ≥40% underwent device implantation followed by hemodynamic assessments at rest and exercise, including pulmonary capillary wedge pressure (PCWP, surrogate for left atrial pressure) and central venous pressure (CVP). At 6 months, IASD resulted in an average pulmonary-to-systemic blood flow ratio of 1.27 and increased exercise tolerance. The PCWP-CVP gradient (ie, the driving pressure for shunt flow) decreased at peak exercise from 16.8±6.9 to 11.4±5.5 mm Hg, because of increased CVP (17.5±5.4 to 20.3±7.9 mm Hg; P =0.04) and decreased PCWP (34.1±7.6 to 31.6±8.0 mm Hg; P =0.025). Baseline PCWP-CVP gradient during exercise correlated with changes of both PCWP-CVP and PCWP: Δ(PCWP-CVP)=10.0−0.89·(PCWP-CVP) baseline ( r 2 =0.56) and ΔPCWP=7.54−0.60·(PCWP-CVP) baseline ( P =0.001). Hemodynamics of patients with EF ≥50% and those with EF <50% responded similarly to IASD. Conclusions In heart failure patients with EF ≥40%, IASD significantly reduced PCWP and PCWP-CVP at peak exercise. Patients with higher baseline PCWP-CVP gradient had greater reductions in both parameters at follow-up. Results were sustained through 12 months and were independent of whether EF was ≥50% or between 40% and 49%. Additional studies will help further define the baseline hemodynamic predictors of exercise, hemodynamic, and clinical efficacy of the IASD. Clinical Trial Registration URL: https://www.clinicaltrials.gov . Unique identifier: NCT01913613.

Background: To describe the baseline characteristics of patients with heart failure and preserved left ventricular ejection fraction enrolled in the PARAGON-HF trial (Prospective Comparison of Angiotensin Receptor Neprilysin Inhibitor With Angiotensin Receptor Blocker Global Outcomes in HFpEF) comparing sacubitril/valsartan to valsartan in reducing morbidity and mortality. Methods and Results: We report key demographic, clinical, and laboratory findings, and baseline therapies, of 4822 patients randomized in PARAGON-HF, grouped by factors that influence criteria for study inclusion. We further compared baseline characteristics of patients enrolled in PARAGON-HF with those patients enrolled in other recent trials of heart failure with preserved ejection fraction (HFpEF). Among patients enrolled from various regions (16% Asia-Pacific, 37% Central Europe, 7% Latin America, 12% North America, 28% Western Europe), the mean age of patients enrolled in PARAGON-HF was 72.7±8.4 years, 52% of patients were female, and mean left ventricular ejection fraction was 57.5%, similar to other trials of HFpEF. Most patients were in New York Heart Association class II, and 38% had ≥1 hospitalizations for heart failure within the previous 9 months. Diabetes mellitus (43%) and chronic kidney disease (47%) were more prevalent than in previous trials of HFpEF. Many patients were prescribed angiotensin-converting enzyme inhibitors or angiotensin receptor blockers (85%), β-blockers (80%), calcium channel blockers (36%), and mineralocorticoid receptor antagonists (24%). As specified in the protocol, virtually all patients were on diuretics, had elevated plasma concentrations of N-terminal pro-B-type natriuretic peptide (median, 911 pg/mL; interquartile range, 464–1610), and structural heart disease. Conclusions: PARAGON-HF represents a contemporary group of patients with HFpEF with similar age and sex distribution compared with prior HFpEF trials but higher prevalence of comorbidities. These findings provide insights into the impact of inclusion criteria on, and regional variation in, HFpEF patient characteristics. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov . Unique identifier: NCT01920711.

Background: Patients with combined post- and precapillary pulmonary hypertension due to left heart disease have a worse prognosis compared with isolated postcapillary. However, it remains unclear whether increased mortality in combined post- and precapillary pulmonary hypertension is simply a result of higher total right ventricular load. Pulmonary effective arterial elastance (Ea) is a measure of total right ventricular afterload, reflecting both resistive and pulsatile components. We aimed to test whether pulmonary Ea discriminates survivors from nonsurvivors in patients with pulmonary hypertension due to left heart disease and if it does so better than other hemodynamic parameters associated with combined post- and precapillary pulmonary hypertension. Methods and Results: We combined 3 large heart failure patient cohorts (n=1036) from academic hospitals, including patients with pulmonary hypertension due to heart failure with preserved ejection fraction (n=232), reduced ejection fraction (n=335), and a mixed population (n=469). In unadjusted and 2 adjusted models, pulmonary Ea more robustly predicted mortality than pulmonary vascular resistance and the transpulmonary gradient. Along with pulmonary arterial compliance, pulmonary Ea remained predictive of survival in patients with normal pulmonary vascular resistance. The diastolic pulmonary gradient did not predict mortality. In addition, in a subset of patients with echocardiographic data, Ea and pulmonary arterial compliance were better discriminators of right ventricular dysfunction than the other parameters. Conclusions: Pulmonary Ea and pulmonary arterial compliance more consistently predicted mortality than pulmonary vascular resistance or transpulmonary gradient across a spectrum of left heart disease with pulmonary hypertension, including patients with heart failure with preserved ejection fraction, heart failure with reduced ejection fraction, and pulmonary hypertension with a normal pulmonary vascular resistance.