The function of the right ventricle determines the fate of patients with pulmonary hypertension. Since right heart failure is the consequence of increased afterload, a full physiological description ...of the cardiopulmonary unit consisting of both the right ventricle and pulmonary vascular system is required to interpret clinical data correctly. Here, we provide such a description of the unit and its components, including the functional interactions between the right ventricle and its load. This physiological description is used to provide a framework for the interpretation of right heart catheterisation data as well as imaging data of the right ventricle obtained by echocardiography or magnetic resonance imaging. Finally, an update is provided on the latest insights in the pathobiology of right ventricular failure, including key pathways of molecular adaptation of the pressure overloaded right ventricle. Based on these outcomes, future directions for research are proposed.
The pathobiology of pulmonary arterial hypertension (PAH) is complex and incompletely understood. Although three pathogenic pathways have been relatively well characterised, it is widely accepted ...that dysfunction in a multitude of other cellular processes is likely to play a critical role in driving the development of PAH. Currently available therapies, which all target one of the three well-characterised pathways, provide significant benefits for patients; however, PAH remains a progressive and ultimately fatal disease. The development of drugs to target alternative pathogenic pathways is, therefore, an attractive proposition and one that may complement existing treatment regimens to improve outcomes for patients. Considerable research has been undertaken to identify the role of the less well-understood pathways and in this review we will highlight some of the key discoveries and the potential for utility as therapeutic targets.
Pulmonary vascular disease, including pulmonary arterial hypertension (PAH), is increasingly recognized to be affected by systemic alterations including up‐regulation of the ...renin‐angiotensin‐aldosterone system and perturbations to metabolic pathways, particularly glucose and fat metabolism. There is increasing preclinical and clinical data that each of these pathways can promote pulmonary vascular disease and right heart failure and are not simply disease markers. More recently, trials of therapeutics aimed at neurohormonal activation or metabolic dysfunction are beginning to shed light on how interventions in these pathways may affect patients with PAH. This review will focus on underlying mechanistic data that supports neurohormonal activation and metabolic dysfunction in the pathogenesis of PAH and right heart failure as well as discussing early translational data in patients with PAH.
Right ventricular (RV) adaptation to acute and chronic pulmonary hypertensive syndromes is a significant determinant of short- and long-term outcomes. Although remarkable progress has been made in ...the understanding of RV function and failure since the meeting of the NIH Working Group on Cellular and Molecular Mechanisms of Right Heart Failure in 2005, significant gaps remain at many levels in the understanding of cellular and molecular mechanisms of RV responses to pressure and volume overload, in the validation of diagnostic modalities, and in the development of evidence-based therapies.
A multidisciplinary working group of 20 international experts from the American Thoracic Society Assemblies on Pulmonary Circulation and Critical Care, as well as external content experts, reviewed the literature, identified important knowledge gaps, and provided recommendations.
This document reviews the knowledge in the field of RV failure, identifies and prioritizes the most pertinent research gaps, and provides a prioritized pathway for addressing these preclinical and clinical questions. The group identified knowledge gaps and research opportunities in three major topic areas: 1) optimizing the methodology to assess RV function in acute and chronic conditions in preclinical models, human studies, and clinical trials; 2) analyzing advanced RV hemodynamic parameters at rest and in response to exercise; and 3) deciphering the underlying molecular and pathogenic mechanisms of RV function and failure in diverse pulmonary hypertension syndromes.
This statement provides a roadmap to further advance the state of knowledge, with the ultimate goal of developing RV-targeted therapies for patients with RV failure of any etiology.
Abstract Background Pulmonary hypertension and associated right ventricular (RV) dysfunction are important determinants of morbidity and mortality, which are optimally characterized by invasive ...hemodynamic measurements. Objectives This study sought to determine whether metabolite profiling could identify plasma signatures of right ventricular-pulmonary vascular (RV-PV) dysfunction. Methods We measured plasma concentrations of 105 metabolites using targeted mass spectrometry in 71 individuals (discovery cohort) who underwent comprehensive physiological assessment with right-sided heart catheterization and radionuclide ventriculography at rest and during exercise. Our findings were validated in a second cohort undergoing invasive hemodynamic evaluations (n = 71), as well as in an independent cohort with or without known pulmonary arterial (PA) hypertension (n = 30). Results In the discovery cohort, 21 metabolites were associated with 2 or more hemodynamic indicators of RV-PV function (i.e., resting right atrial pressure, mean PA pressure, pulmonary vascular resistance PVR, and PVR and PA pressure-flow response ΔPQ during exercise). We identified novel associations of RV-PV dysfunction with circulating indoleamine 2,3-dioxygenase (IDO)–dependent tryptophan metabolites (TMs), tricarboxylic acid intermediates, and purine metabolites and confirmed previously described associations with arginine–nitric oxide metabolic pathway constituents. IDO-TM levels were inversely related to RV ejection fraction and were particularly well correlated with exercise PVR and ΔPQ. Multisite sampling demonstrated transpulmonary release of IDO-TMs. IDO-TMs also identified RV-PV dysfunction in a validation cohort with known risk factors for pulmonary hypertension and in patients with established PA hypertension. Conclusions Metabolic profiling identified reproducible signatures of RV-PV dysfunction, highlighting both new biomarkers and pathways for further functional characterization.
Abstract Background Pulmonary hypertension (PH) is a common and morbid complication of left heart disease with 2 subtypes: isolated post-capillary pulmonary hypertension (Ipc-PH) and combined ...post-capillary and pre-capillary pulmonary hypertension (Cpc-PH). Little is known about the clinical or physiological characteristics that distinguish these 2 subphenotypes or if Cpc-PH shares molecular similarities to pulmonary arterial hypertension (PAH). Objectives The goal of this study was to test the hypothesis that the hemodynamic and genetic profile of Cpc-PH would more closely resemble PAH than Ipc-PH. Methods Vanderbilt University’s electronic medical record linked to a DNA biorepository was used to extract demographic characteristics, clinical data, invasive hemodynamic data, echocardiography, and vital status for all patients referred for right heart catheterization between 1998 and 2014. Shared genetic variants between PAH and Cpc-PH compared with Ipc-PH were identified by using pre-existing single-nucleotide polymorphism data. Results A total of 2,817 patients with PH (13% Cpc-PH, 52% Ipc-PH, and 20% PAH) were identified. Patients with Cpc-PH were on average 6 years younger, with more severe pulmonary vascular disease than patients with Ipc-PH, despite similar comorbidities and prevalence, severity, and chronicity of left heart disease. After adjusting for relevant covariates, the risk of death was similar between the Cpc-PH and Ipc-PH groups (hazard ratio: 1.14; 95% confidence interval: 0.96 to 1.35; p = 0.15) when defined according to diastolic pressure gradient. We identified 75 shared exonic single-nucleotide polymorphisms between Cpc-PH and PAH enriched in pathways involving cell structure, extracellular matrix, and immune function. These genes are expressed, on average, 32% higher in lungs relative to other tissues. Conclusions Patients with Cpc-PH develop pulmonary vascular disease similar to patients with PAH, despite younger age and similar prevalence of obesity, diabetes mellitus, and left heart disease compared with patients with Ipc-PH. An exploratory genetic analysis in Cpc-PH identified genes and biological pathways in the lung known to contribute to PAH pathophysiology, suggesting that Cpc-PH may be a distinct and highly morbid PH subphenotype.
Phosphodiesterase-5 inhibitors (PDE-5I) have demonstrated improvement in disease symptoms and quality of life for patients with pulmonary arterial hypertension (PAH). Despite these benefits, reported ...adherence to PDE-5I therapy is sub-optimal. Clinical pharmacists at an integrated practice site are in a unique position to mitigate barriers related to PAH therapy including medication adherence and costs. The primary objective of this study was to assess medication adherence to PDE-5I therapy within an integrated care model at an academic institution. The secondary objective was to assess the impact of out-of-pocket (OOP) cost, frequency of dosing, adverse events (AE) and PAH-related hospitalizations on medication adherence. We performed a retrospective cohort analysis of adult patients with PAH who were prescribed PDE-5I therapy by the center's outpatient pulmonary clinic and who received medication management through the center's specialty pharmacy. We defined optimal medication adherence as proportion of days covered (PDC) ≥ 80%. Clinical data including AEs and PAH-related hospitalizations were extracted from the electronic medical record, and financial data from pharmacy claims. Of the 131 patients meeting inclusion criteria, 94% achieved optimal adherence of ≥ 80% PDC. In this study population, 47% of patients experienced an AE and 27% had at least one hospitalization. The median monthly OOP cost was $0.62. Patients with PDC<80% were more likely to report an AE compared to patients with PDC≥ 80% (p = 0.002). Hospitalization, OOP cost, and frequency of dosing were not associated with adherence in this cohort. Patients receiving PDE-5I therapy through an integrated model achieved high adherence rates and low OOP costs.
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Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The authors demonstrated that CD44v+ cells may have a survival advantage via CD44-mediated stabilization of a cystine-glutamate antiporter, xCT, a cell-surface receptor that is known to promote ...antioxidant glutathione synthesis via cystine import and thus to enhance the scavenging of reactive oxygen species. ...using a well-established model of chronic hypoxia and vascular endothelial growth factor inhibitor–induced pulmonary hypertension (Sugen + hypoxia), the authors demonstrate that treatment with sulfasalazine, which functions in part by inhibiting xCT-mediated cystine transport, prevented and partially reversed pulmonary hypertension by reducing vascular remodeling in vivo. ...given that EndMT has been implicated in the microvasculature of many organs beyond the lung (18), it would be intriguing to study whether sulfasalazine or a similar therapy could be beneficial for treating other PAH-related complications, such right ventricular failure. If they are truly effective in altering multiorgan dysfunction in PAH, sulfasalazine and other immunomodulatory therapies may also have a role in altering disease pathogenesis in other groups of patients with pulmonary hypertension who do not derive a benefit from known PAH-specific vasodilating therapies, i.e., patients with World Health Organization Group 2 pulmonary hypertension due to primary cardiac disease (19–21).
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