Novel therapeutic approaches to preserve the right ventricle

Predictors of mortality in heart failure with reduced ejection fraction: interaction between diabetes mellitus and impaired renal function

BACKGROUND

The harmful effect of diabetes mellitus (DM) on mortality in patients with heart failure with reduced ejection fraction (HFrEF) remains controversial. Furthermore, it seems that no consistent conclusion on whether chronic kidney disease (CKD) modifies the relationship of DM and poor prognosis in patients with HFrEF.

METHODS

We analyzed the individuals with HFrEF from the Cardiorenal ImprovemeNt (CIN) cohort between January 2007 and December 2018. The primary endpoint was all-cause mortality. The patients were divided into four groups (control vs. DM alone vs. CKD alone vs. DM and CKD). Multivariate Cox proportional hazards analysis was conducted to examine the association among DM, CKD and all-cause mortality.

RESULTS

There were 3,273 patients included in this study (mean age: 62.7 ± 10.9 years, 20.4% were female). During a median follow-up of 5.0 years (interquartile range: 3.0-7.6 years), 740 (22.6%) patients died. Patients with DM have a higher risk of all-cause mortality (HR [95% confidence interval (CI)]:1.28[1.07-1.53]) than those without DM. In patients with CKD, DM had a 61% (HR [95% CI]:1.61[1.26-2.06]) increased adjusted risk of death relative to non-DM, while in patients with non-CKD, there was no significantly difference in risk of all-cause mortality (HR [95% CI]:1.01[0.77-1.32]) between DM and non-DM (p for interaction = 0.013).

CONCLUSIONS

Diabetes is a potent risk factor for mortality in patients with HFrEF. Furthermore, DM had a substantially different effect on all-cause mortality depending on CKD. The association between DM and all-cause mortality was only observed in patients with CKD.

Prognostic Implications of Mechanical Phenotypes in Heart Failure Characterized by 3-Chamber Strain Echocardiography

Background Heart failure (HF) involves dysfunction of the left ventricle (LV) as well as left atrium and right ventricle. We characterized mechanical phenotypes of HF using 3-chamber strain echocardiography and compared their clinical outcomes. Methods and Results We retrospectively analyzed 3574 patients (median age, 74 years; male 52.8%) with acute HF who underwent 3-chamber strain echocardiography. Patients were classified as with LV, left atrium, or right ventricle myopathy if their corresponding strain values (LV global longitudinal strain, left atrium reservoir strain, and right ventricle global longitudinal strain) were lower than median cutoffs, respectively. The mechanical phenotypes of individual patients were characterized according to the combined myopathy. The primary outcome was a composite end point of 5-year all-cause mortality and HF hospitalization. During follow-up (median, 25.8 months), the primary outcome occurred in 1877 (52.5%) patients. Three-chamber strain values were independent predictors for the primary outcome. An incremental trend was observed for the primary outcome, along with the increasing numbers of combined myopathy. Each mechanical phenotype exhibited an increased risk of the primary outcome, with the highest risk observed in patients with 3-chamber myopathy (hazard ratio, 1.67 [95% CI, 1.42-1.96]). The prognostic significance of the mechanical phenotypes was feasible across the conventional HF subtypes stratified by LV ejection fraction. In HF with preserved ejection fraction, the presence of left atrium and right ventricle myopathy significantly increased the primary outcome, regardless of combined left ventricle myopathy. Conclusions Assessment of 3-chamber strain in HF enables characterization of distinctive mechanical phenotypes, which provides an independent prognostic value that may support long-term risk stratification.

Influence of Right Ventricular Dysfunction on Outcomes of Left Ventricular Non-compaction Cardiomyopathy

Background

Various adverse outcomes such as mortality and rehospitalization are associated with left ventricular non-compaction (LVNC). Due to data limitations, prospective risk assessment for LVNC remains challenging. This study aimed to investigate the influence of right ventricular (RV) dysfunction on the clinical outcomes of patients with LVNC through accurate and comprehensive measurements of RV function.

Methods and Results

Overall, 117 patients with LVNC (47.6 ± 18.3 years, 34.2% male) were enrolled, including 53 (45.3%) and 64 (54.7%) patients with and without RV dysfunction, respectively. RV dysfunction was defined as meeting any two of the following criteria: (i) tricuspid annular systolic excursions <17 mm, (ii) tricuspid S′ velocity <10 cm/s, and (iii) RV fractional area change (FAC) <35%. The proportion of biventricular involvement was significantly higher in patients with RV dysfunction than in controls (p = 0.0155). After a follow-up period of 69.0 [33.5, 96.0] months, 18 (15.4%) patients reached the primary endpoint (all-cause mortality), with 14 (26.4%) and 4 (6.3%) from the RV dysfunction group and normal RV function group, respectively. The Kaplan–Meier method and log-rank test revealed that patients with RV dysfunction had a higher risk of all-cause mortality than those in the control group (hazard ratio [HR]: 5.132 [2.003, 13.15], p = 0.0013). Similar results were obtained for patients with left ventricular ejection fraction (LVEF) <50% [HR, 6.582; 95% confidence interval (CI), 2.045–21.19; p = 0.0367]. The relationship between RV dysfunction and heart failure rehospitalization and implantation of implantable cardioverter-defibrillator (ICD)/cardiac resynchronization therapy (CRT) was not statistically significant (both p > 0.05). The multivariable Cox proportional hazard modeling analysis showed that RV dysfunction (HR: 4.950 [1.378, 17.783], p = 0.014) and impaired RV global longitudinal strain (RVGLS) (HR: 1.103 [1.004, 1.212], p = 0.041) were independent predictors of mortality rather than increased RV end-diastolic area and decreased LVEF (both p > 0.05).

Conclusions

RV dysfunction is associated with the prognosis of patients with LVNC.

Metabolic endophenotype associated with right ventricular glucose uptake in pulmonary hypertension

Alterations in metabolism and bioenergetics are hypothesized in the mechanisms leading to pulmonary vascular remodeling and heart failure in pulmonary hypertension (PH). To test this, we performed metabolomic analyses on 30 PH individuals and 12 controls. Furthermore, using 2-[18F]fluoro-2-deoxy-D-glucose positron emission tomography, we dichotomized PH patients into metabolic phenotypes of high and low right ventricle (RV) glucose uptake and followed them longitudinally. In support of metabolic alterations in PH and its progression, the high RV glucose group had higher RV systolic pressure (p < 0.001), worse RV function as measured by RV fractional area change and peak global longitudinal strain (both p < 0.05) and may be associated with poorer outcomes (33% death or transplantation in the high glucose RV uptake group compared to 7% in the low RV glucose uptake group at five years follow-up, log-ranked p = 0.07). Pathway enrichment analysis identified key metabolic pathways including fructose catabolism, arginine-nitric oxide metabolism, tricarboxylic acid cycle, and ketones metabolism. Integrative human protein-protein interactome network analysis of metabolomic and transcriptomic data identified key pathobiological pathways: arginine biosynthesis, tricarboxylic acid cycle, purine metabolism, hypoxia-inducible factor 1, and apelin signaling. These findings identify a PH metabolomic endophenotype, and for the first time link this to disease severity and outcomes.

Right ventricular phenotype, function, and failure: a journey from evolution to clinics

The right ventricle has long been perceived as the "low pressure bystander" of the left ventricle. Although the structure consists of, at first glance, the same cardiomyocytes as the left ventricle, it is in fact derived from a different set of precursor cells and has a complex three-dimensional anatomy and a very distinct contraction pattern. Mechanisms of right ventricular failure, its detection and follow-up, and more specific different responses to pressure versus volume overload are still incompletely understood. In order to fully comprehend right ventricular form and function, evolutionary biological entities that have led to the specifics of right ventricular physiology and morphology need to be addressed. Processes responsible for cardiac formation are based on very ancient cardiac lineages and within the first few weeks of fetal life, the human heart seems to repeat cardiac evolution. Furthermore, it appears that most cardiogenic signal pathways (if not all) act in combination with tissue-specific transcriptional cofactors to exert inductive responses reflecting an important expansion of ancestral regulatory genes throughout evolution and eventually cardiac complexity. Such molecular entities result in specific biomechanics of the RV that differs from that of the left ventricle. It is clear that sole descriptions of right ventricular contraction patterns (and LV contraction patterns for that matter) are futile and need to be addressed into a bigger multilayer three-dimensional picture. Therefore, we aim to present a complete picture from evolution, formation, and clinical presentation of right ventricular (mal)adaptation and failure on a molecular, cellular, biomechanical, and (patho)anatomical basis.

Right ventricle and outcome in left ventricular non-compaction cardiomyopathy

BACKGROUND

The risk of adverse events in patients with left ventricular non-compaction cardiomyopathy (LVNC) is substantial. Information on prognostic factors, however, is limited. This study was designed to assess the prognostic value of right ventricular (RV) size and function in LVNC patients.

METHODS

Cox regression analyses were used to determine the association of indexed RV end-diastolic area (RV-EDAI), indexed end-diastolic diameter (RV-EDDI), fractional area change (FAC), and tricuspid annular systolic excursion (TAPSE) with the occurrence of death or heart transplantation (composite endpoint).

RESULTS

Out of 127 patients (53.2 ± 17.8 years; 61% males, median follow-up time was 7.7 years), 17 patients reached the endpoint. In a univariate analysis, RV-EDAI was the strongest predictor of outcome [HR 1.48 (1.24-1.77) per cm²/m²; p < 0.0001]. FAC was predictive as well [HR 1.44 (1.16-1.83) per 5% decrease; p = 0.0009], while TAPSE was not (p=ns). RV-EDAI remained an independent predictor in a bivariable analysis with indexed left ventricular ED volume [HR 1.41 (1.18-1.70) per cm²/m²; p = 0.0002], while analysis of FAC and left ventricular ejection fraction demonstrated that FAC was not independent [HR 1.20 (0.98-1.52); per 5% decrease; p = 0.0721]. RV-EDAI 11.5 cm²/m² was the best cut-off value for separating patients in terms of outcome. Patients with RV-EDAI >11.5 cm²/m² had a survival rate of 18.5% over 12 years as compared to 93.8% in patients with RV-EDAI <11.5 cm²/m² (p < 0.0001).

CONCLUSION

Increased end-diastolic RV size and decreased systolic RV function are predictors of adverse outcome in patients with LVNC. Patients with RV-EDAI >11.5 cm²/m² exhibit a significantly lower survival than those <11.5 cm²/m².

Right ventricular dysfunction and remodeling in diabetic cardiomyopathy

The increasing prevalence of diabetic cardiomyopathy (DCM) is an important threat to health worldwide. While left ventricular (LV) dysfunction in DCM is well recognized, the accurate detection, diagnosis, and treatment of changes in right ventricular (RV) structure and function have not been well characterized. The pathophysiology of RV dysfunction in DCM may share features with LV diastolic and systolic dysfunction, including pathways related to insulin resistance and oxidant injury, although the RV has a unique cellular origin and composition and unique biomechanical properties and is coupled to the lower-impedance pulmonary vascular bed. In this review, we discuss potential mechanisms responsible for RV dysfunction in DCM and review the imaging approaches useful for early detection, protection, and intervention strategies. Additional data are required from animal models and clinical trials to better identify the onset and features of altered RV and pulmonary vascular structure and function during the onset and progression of DCM and to determine the efficacy of early detection and treatment of RV dysfunction on clinical symptoms and outcomes.

Acute Right Heart Failure

Heart failure is defined as a life-threatening complex clinical syndrome with exacerbation of symptoms signifying decompensation and requires emergent treatment. In its acute state it presents within 24 hours with symptoms such as shortness of breath, volume overload including pulmonary edema, sometimes forward failure and even cardiogenic shock. Two forms of acute heart failure exist: newly diagnosed “de novo” or acutely decompensated chronic heart failure. This chapter summarizes the clinical and prognostic classification of acute right heart failure, epidemiology, diagnostic work-up and the principles behind treatment and management options that focus on preload optimization, afterload reduction and improvement of contractility.

Right heart dysfunction and failure in heart failure with preserved ejection fraction: mechanisms and management. Position statement on behalf of the Heart Failure Association of the European Society of Cardiology

There is an unmet need for effective treatment strategies to reduce morbidity and mortality in patients with heart failure with preserved ejection fraction (HFpEF). Until recently, attention in patients with HFpEF was almost exclusively focused on the left side. However, it is now increasingly recognized that right heart dysfunction is common and contributes importantly to poor prognosis in HFpEF. More insights into the development of right heart dysfunction in HFpEF may aid to our knowledge about this complex disease and may eventually lead to better treatments to improve outcomes in these patients. In this position paper from the Heart Failure Association of the European Society of Cardiology, the Committee on Heart Failure with Preserved Ejection Fraction reviews the prevalence, diagnosis, and pathophysiology of right heart dysfunction and failure in patients with HFpEF. Finally, potential treatment strategies, important knowledge gaps and future directions regarding the right side in HFpEF are discussed.

Regulation and function of miR-214 in pulmonary arterial hypertension

Dysregulation of microRNAs (miRNAs) can contribute to the etiology of diseases, including pulmonary arterial hypertension (PAH). Here we investigated a potential role for the miR-214 stem loop miRNA and the closely linked miR-199a miRNAs in PAH. All 4 miRNAs were upregulated in the lung and right ventricle (RV) in mice and rats exposed to the Sugen (SU) 5416 hypoxia model of PAH. Further, expression of the miRNAs was increased in pulmonary artery smooth muscle cells exposed to transforming growth factor β1 but not BMP4. We then examined miR-214(-/-) mice exposed to the SU 5416 hypoxia model of PAH or normoxic conditions and littermate controls. There were no changes in RV systolic pressure or remodeling observed between the miR-214(-/-) and wild-type hypoxic groups. However, we observed a significant increase in RV hypertrophy (RVH) in hypoxic miR-214(-/-) male mice compared with controls. Further, we identified that the validated miR-214 target phosphatase and tensin homolog was upregulated in miR-214(-/-) mice. Thus, miR-214 stem loop loss leads to elevated RVH and may contribute to the heart failure associated with PAH.

Modulation of endothelin receptors in the failing right ventricle of the heart and vasculature of the lung in human pulmonary arterial hypertension

AIMS

In pulmonary arterial hypertension (PAH), increases in endothelin-1 (ET-1) contribute to elevated pulmonary vascular resistance which ultimately causes death by right ventricular (RV) heart failure. ET antagonists are effective in treating PAH but lack efficacy in treating left ventricular (LV) heart failure, where ETA receptors are significantly increased. The aim was to quantify the density of ETA and ETB receptors in cardiopulmonary tissue from PAH patients and the monocrotaline (MCT) rat, which recapitulates some of the pathophysiological features, including increased RV pressure.

MAIN METHODS

Radioligand binding assays were used to quantify affinity, density and ratio of ET receptors.

KEY FINDINGS

In RV from human PAH hearts, there was a significant increase in the ratio of ETA to ETB receptors compared with normal hearts. In the RV of the MCT rat, the ratio also changed but was reversed. In both human and rat, there was no change in LV. In human PAH lungs, ETA receptors were significantly increased in the medial layer of small pulmonary arteries with no change detectable in MCT rat vessels.

SIGNIFICANCE

Current treatments for PAH focus mainly on pulmonary vasodilatation. The increase in ETA receptors in arteries provides a mechanism for the beneficial vasodilator actions of ET antagonists. The increase in the ratio of ETA in RV also implicates changes to ET signalling although it is unclear if ET antagonism is beneficial but the results emphasise the unexploited potential for therapies that target the RV, to improve survival in patients with PAH.