Redfield, Margaret M.

Myofiber passive stiffness is lowered by phosphorylation of the giant sarcomeric protein titin, with beneficial effects on diastolic function. Titin can be phosphorylated by cGMP-activated protein kinase (PK)G, a pathway stimulated by B-type natriuretic peptide (BNP) or PDE-5A inhibitor (sildenafil). Whether titin phosphorylation and stiffness are affected by PKG activation in vivo had not been studied. Here we examined how dogs with experimental hypertension and diastolic dysfunction, induced by renal wrapping, respond to treatment with β-blockers, sildenafil, and BNP, in terms of altered titin phosphorylation and passive stiffness. Isolated permeabilized cardiomyocytes from left ventricular (LV) biopsies untreated (n=5), treated with β-blockers (n=7), followed by sildenafil (n=7) and BNP (n=7) were attached to a force transducer and the passive length tension relation (F pas ) was measured between 1.8 and 2.4µm sarcomere length (SL) before and after PKA and PKG administration. We also assessed phosphorylation of myofilament proteins including titin, cMyBPC, desmin, cTnT, cTnI and MLC2 by gel electrophoresis (SYPRO Ruby and ProQ Diamond stain) and expression of titin PEVK, phospho-PEVK, cTnI, phospho-cTnI (at Ser 23/24), PKCα and phospho-PKCα by Western blotting. Compared to untreated cardiomyocytes, F pas was unaltered with β-blocker therapy, but significantly reduced with sildenafil; with BNP F pas did not change further. Ex-vivo administration of PKG lowered F pas of untreated and β-blocker cardiomyocytes to the levels measured in sildenafil and BNP samples, and additional administration of PKA did not further change F pas . Total titin phosphorylation was low in untreated samples and with β-blockade, but significantly increased with sildenafil and BNP. Total cTnI phosphorylation and phospho-cTnI at Ser 23/24 were low in untreated compared to treated samples but were similar between β-blocker, sildenafil and BNP groups. Phospho-PEVK and phospho-PKCα were high in untreated samples and with β-blockade, but reduced with sildenafil and BNP. Acute cGMP enhancing therapy with sildenafil and BNP improves LV diastolic function through correction of a titin phosphorylation deficit, thereby reducing cardiomyocyte passive stiffness.

Background: Pulmonary hypertension is common in HFpEF and is associated with increased mortality. Pulmonary hypertension can lead to right ventricular systolic dysfunction. However, the magnitude and prognostic significance of RV dysfunction in the HFpEF population are unclear. Hypothesis: RV systolic dysfunction is common in HFpEF and is associated with increased mortality. Methods: RV size and systolic function were assessed qualitatively (as normal or abnormal) and pulmonary artery systolic pressure (PASP) was estimated using echocardiography in 548 consecutive HFpEF subjects (Framingham criteria and EF ≥50%) from a prospective population based study (Olmsted County, Minnesota). Control group was a retrospectively identified random sample of age and sex matched hypertensive (N=360) and normotensive subjects (N=168) from Olmsted County. HFpEF group was followed for up to 5 years (median follow up 4.4 years). Results: See table and figure. RV enlargement and systolic dysfunction were more prevalent in HFpEF compared with age and sex matched hypertensive and normotensive controls. In HFpEF subjects with PASP above the median, RV systolic dysfunction was associated with poor survival compared with normal RV function. RV systolic dysfunction was a significant predictor of mortality even after adjustment for age and PASP in a Cox regression model (Hazard Ratio=1.4, p=0.02). Conclusions: In the community, RV systolic dysfunction is common in HFpEF and is associated with higher mortality. Although quantitative assessment of RV function is difficult owing to its complex geometry, qualitative assessment is feasible on the majority of subjects and provides significant prognostic information.

Background: C-type natriuretic peptide (CNP) is of endothelial cell origin and represents the most potent anti-fibrotic peptide of the natriuretic peptide family and is important for extracellular matrix homeostasis including mediating bone growth in the young. Cardiorenal aging is associated with altered cardiac and renal structure and function that may contribute to the development of heart and kidney failure, particularly in the elderly. The impact of aging on circulating CNP and associated changes in cardiorenal structure and function are undefined. Hypothesis: We hypothesized that a decrease in endogenous plasma CNP occurs with aging and is associated with an increase in cardiorenal fibrosis and altered left ventricular (LV) and renal structure and function. Methods: Studies were performed in 2, 11 and 20 month old male Fischer rats (n = 8 –10/group). Echo was used to assess LV structure and function. Blood pressure (BP), urinary protein excretion, plasma B-type natriuretic peptide (BNP) and CNP were measured. Kidneys and LV were harvested for gross and histology analysis. Mean±SE, *p<0.05. Results: Aging from 2 to 20 months was associated with progressive reductions in plasma CNP (30±3 to 21±1* to 9±1*pg/ml). Significant and progressive cardiac and renal fibrosis were observed with aging (LV: 9±0.3 to 15±0.7* to 21±1*% and kidney: 1±0.3 to 8±2* to 17±1* %). In contrast to CNP, plasma BNP was modestly increased from the 2 to 20 month old group (21±2 to 26±1*pg/ml). The reduction in CNP and increase in BNP, the latter a biomarker for LV dysfunction, were associated with decreased EF (88±1 to 80±1*%) and increased LVEDd (6.61±0.09 to 7.48±0.09*mm). BP and urinary protein excretion were mildly elevated with aging (91±1 to 101±3* mmHg and 8±0.3 to 20±3* mg/day, respectively). Conclusion: We report for the first time that aging is associated with a progressive decline in circulating CNP and progressive cardiorenal fibrosis, systolic dysfunction and proteinuria. Further studies are warranted to explore the hypothesis that a mechanism of cardiorenal aging with altered cardiorenal structure and function may include a decrease in the bioavailability of CNP.

Abstract Pulmonary hypertension (PH) associated with left heart failure (LHF) (PH-LHF) is one of the most common causes of PH. It directly contributes to symptoms and reduced functional capacity and negatively affects right heart function, ultimately leading to a poor prognosis. There are no specific treatments for PH-LHF, despite the high number of drugs tested so far. This scientific document addresses the main knowledge gaps in PH-LHF with emphasis on pathophysiology and clinical trials. Key identified issues include better understanding of the role of pulmonary venous versus arteriolar remodelling, multidimensional phenotyping to recognize patient subgroups positioned to respond to different therapies, and conduct of rigorous pre-clinical studies combining small and large animal models. Advancements in these areas are expected to better inform the design of clinical trials and extend treatment options beyond those effective in pulmonary arterial hypertension. Enrichment strategies, endpoint assessments, and thorough haemodynamic studies, both at rest and during exercise, are proposed to play primary roles to optimize early-stage development of candidate therapies for PH-LHF.

Abstract Aims Left ventricular (LV) subclinical impairment has been described in heart failure with preserved ejection fraction (HFpEF). We assessed the relationship between LV myocardial deformation by strain imaging and recurrent hospitalization for heart failure (HF) or cardiovascular death in a large international HFpEF population. Methods and results We assessed two-dimensional speckle-tracking based global longitudinal strain (GLS) in 790 patients (mean age 74 ± 8 years, 54% female) with adequate image quality enrolled in the PARAGON-HF echocardiography study. We examined the relationship of GLS with total HF hospitalizations and cardiovascular death (the primary composite outcome) after accounting for clinical confounders. Approximately 47% of the population had evidence of LV subclinical dysfunction, defined as absolute GLS &lt;16%. Impaired GLS was significantly associated with higher values of circulating baseline N-terminal pro-B-type-natriuretic peptide. After a median follow-up of 3.0 years, there were 407 total HF hospitalizations and cardiovascular deaths. After multivariable adjustment, worse GLS was associated with a greater risk for the primary composite outcome (adjusted hazard ratio per 1% decrease: 1.06; 95% confidence interval 1.02–1.11; p = 0.008). GLS did not modify the treatment effect of sacubitril/valsartan compared with valsartan for the composite outcome (p for interaction &gt;0.1). Conclusions In a large HFpEF population, impaired LV function was observed even among patients with preserved ejection fraction, and was associated with an increased risk of total HF hospitalizations or cardiovascular death, accounting for clinical confounders. These findings highlight the key role of subtle LV systolic impairment in the pathophysiology of HFpEF.

Abstract Aims We aimed to clarify the extent to which cardiac and peripheral impairments to oxygen delivery and utilization contribute to exercise intolerance and risk for adverse events, and how this relates to diversity and multiplicity in pathophysiologic traits. Methods and results Individuals with heart failure with preserved ejection fraction (HFpEF) and non-cardiac dyspnoea (controls) underwent invasive cardiopulmonary exercise testing and clinical follow-up. Haemodynamics and oxygen transport responses were compared. HFpEF patients were then categorized a priori into previously-proposed, non-exclusive descriptive clinical trait phenogroups, including cardiometabolic, pulmonary vascular disease, left atrial myopathy, and vascular stiffening phenogroups based on clinical and haemodynamic profiles to contrast pathophysiology and clinical risk. Overall, patients with HFpEF (n = 643) had impaired cardiac output reserve with exercise (2.3 vs. 2.8 L/min, p = 0.025) and greater reliance on peripheral oxygen extraction augmentation (4.5 vs. 3.8 ml/dl, p &lt; 0.001) compared to dyspnoeic controls (n = 219). Most (94%) patients with HFpEF met criteria for at least one clinical phenogroup, and 67% fulfilled criteria for multiple overlapping phenogroups. There was greater impairment in peripheral limitations in the cardiometabolic group and greater cardiac output limitations and higher pulmonary vascular resistance during exertion in the other phenogroups. Increasing trait multiplicity within a given patient was associated with worse exercise haemodynamics, poorer exercise capacity, lower cardiac output reserve, and greater risk for heart failure hospitalization or death (hazard ratio 1.74, 95% confidence interval 1.08–2.79 for 0–1 vs. ≥2 phenogroup traits present). Conclusions Though cardiac output response to exercise is limited in patients with HFpEF compared to those with non-cardiac dyspnoea, the relative contributions of cardiac and peripheral limitations vary with differing numbers and types of clinical phenotypic traits present. Patients fulfilling criteria for greater multiplicity and diversity of HFpEF phenogroup traits have poorer exercise capacity, worsening haemodynamic perturbations, and greater risk for adverse outcome.

Introduction: Common genetic variation has been linked to an increased risk of developing dilated cardiomyopathy (DCM). However, the phenotypic profile, outcomes, and biological mechanisms by which such genetic background may predispose individuals to DCM are still unknown. Hypothesis: The primary objectives of this study were to develop a DCM polygenic risk score (PRS) based on prior case control-DCM GWAS and to apply this PRS to a well clinical characterized general population. Methods: The DCM-PRS was derived from 13 DCM risk alleles that were assayed in an unselected cohort (n=1897) of unrelated Olmsted County residents age >45 years who did not have a history of heart failure (HF) or CM and underwent physical examination, echocardiography, and blood analyses. Results: The entire population was equally divided into quartiles based on the DCM-PRS. No significant differences were present in terms of age (median 62 years) and sex (48% male). However, a significant correlation was detected between the DCM-PRS and left ventricle ejection fraction (LVEF) (Beta: -2.68, p<0.001), LV end-systolic diameter (Beta: 0.22, p<0.001), and LV end-diastolic diameter (Beta: 0.14, p=0.01). During a follow-up of 16 years (IQR: 15-17), 47 subjects developed DCM. Using a 3:1 non-DCM vs DCM matched cohort, a logistic regression analysis, found a significant correlation between median DCM-PRS and DCM development [OR=2.27 (1.06, 4.85), p=0.03]. However, there was no association between the DCM-PRS and HF biomarkers (aldosterone, natriuretic peptides, ST2, Galectin-3). Conclusions: DCM-PRS correlates with decreased LVEF, increased LV dimensions, and DCM development in a general population without significant differences in baseline clinical features. The absence of correlation between the DCM-PRS and available HF biomarkers suggests that this genetic background affects LV traits and DCM development independent of these biological mechanisms.

Introduction: The epidemiology and pathophysiology of heart failure (HF) differs in women and men. However, it is not well defined whether these differences extend to the subgroup of patients that develop advanced HF or if they translate to differences in outcomes. Aim: To compare the clinical characteristics and outcomes of advanced HF in women and men. Methods: This is a retrospective cohort study of all adult residents of Olmsted County, Minnesota with advanced HF (as defined by European Society of Cardiology Criteria) from 2007-2017. Differences in survival and hospitalization risks following advanced HF development in women and men were examined using Cox proportional hazard regression and Andersen Gill models, respectively. Results: Of 936 individuals with advanced HF, 417 (44.6%) were women and 519 (55.4%) were men. Women were older (mean 79 vs 75 years) with a lower overall comorbidity burden (Charlson comorbidity index 4.7 vs 5.2), less often had coronary artery disease (60% vs 79%) and hyperlipidemia (69% vs 77%), but more often had hypertension (91% vs 87%) and depression (32% vs 24%), and more often had advanced HF with preserved ejection fraction (60% vs. 30%) compared with men ( p<0.05 for each). After adjustment for age, ejection fraction and comorbidities, there were no differences in risks of survival or hospitalizations ( Figure ) between women and men (p> 0.10 for each). Conclusion: While advanced HF can occur in both women and men, their phenotypes differ; women more often present with advanced HFpEF and men with more atherosclerotic disease and advanced HFrEF. Despite these differences, survival is similar in women and men with advanced HF.

Introduction: Impaired tricuspid annular plane systolic excursion (TAPSE), fractional area change (FAC) and right ventricular free wall longitudinal strain (RVFWLS) have been individually associated with a worse prognosis in patients with heart failure with preserved ejection fraction (HFpEF). However, these parameters measure different aspects of RV function and understanding their cumulative effect may provide insights into the overall impact of RV dysfunction (RVD) in HFpEF patients. Goal: Assess the association between the number of echocardiographic RVD parameters and clinical outcomes. Methods: Patients from the echocardiographic sub-study of the PARAGON-HF trial with adequate image quality (N=809, 53% women, mean age 74±8 years) were categorized based on the number of measures of RVD, which included TAPSE <1.7 cm, FAC <35% or RVFWLS <20% (absolute value). Associations with total HF hospitalizations (HFH) and CV death, total HFH alone, first HFH or CV death, all-cause death and CV death were assessed by Groups, after accounting for confounders. Results: A total of 348 patients (43%) in Group 0 (no abnormal parameter), 355 (44%) in Group 1 (one abnormal parameter) and 106 (13%) in Group 2 (two or more abnormal parameters) were identified. After multivariable adjustment ( Table ), Group 2 was significantly associated with an increased risk of total HFH and CV death (RR 2.13, 95%CI 1.13-4.01), first HFH or CV death (RR 2.07, 95%CI 1.15-3.73), all-cause death (RR 2.61, 95%CI 1.19-5.74) and CV death (RR 3.08, 95%CI 1.14-8.31). The treatment effect of sacubitril/valsartan for total HFH and CV death was not modified by RVD Group (p-value for interaction=0.94). Conclusions: The presence of two or more RVD parameters was associated with a significantly worse prognosis, while an isolated RVD measure was not. These findings suggest that a more comprehensive approach to assessment of RV function may have better prognostic value in HFpEF.

Introduction: Right ventricular dysfunction (RVD) is a major prognostic factor in patients with heart failure with preserved ejection fraction (HFpEF), however determinants of RVD in HFpEF are not well described. Although sex-specific mechanisms have been incriminated in the development of HFpEF, it is unclear whether this is also true for RVD. Goals: (1) Assess the prevalence of RVD (defined as a tricuspid annular plane systolic excursion [TAPSE] <1.7 cm, a fractional area change [FAC] <35% or a RV free wall longitudinal strain [RVFWLS] <20%, absolute value) in patients with HFpEF; (2) identify determinants of RVD, overall and according to sex, in patients with HFpEF. Methods: We used data from patients enrolled in the echocardiographic sub-study of the PARAGON-HF trial with adequate image quality (N=809, 53% women, mean age 74±8 years). Determinants of RVD, in the whole study population and according to sex, were identified using a multivariable logistic regression model. Results: There were 461 patients (57%) with RVD. After multivariable adjustment, RVD was cross-sectionally associated with a history of atrial fibrillation of flutter (AFF), older age, higher heart rate, greater LV mean wall thickness and higher NT-proBNP values. Systolic blood pressure and LV global longitudinal strain (absolute value) showed an inverse association ( Figure ). These results were consistent between men and women, except for AFF and LV mean wall thickness, which were associated with a greater likelihood of RVD in men (OR 2.46, 95%CI 1.33-4.56, OR 1.61, 95%CI 1.18-2.21 respectively) but not in women (OR 0.99, 95%CI 0.58-1.68, OR 0.90 95%CI 0.69-1.17 respectively, p-values for interaction=0.028 and 0.006). Conclusions: RVD was highly prevalent in our study population. Determinants of RVD included AFF, LV remodeling and systolic impairment, and increased NT-proBNP levels. Differences between men and women suggest gender-specific mechanisms in the development of RVD in HFpEF.