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.

• Keywords
• Drug, Heart failure, Pulmonary hypertension, Therapy, Translational,
• MeSH
• Ventricular Function, Right * physiology   MeSH
• Humans MeSH
• Hypertension, Pulmonary * physiopathology   etiology   therapy   MeSH
• Pulmonary Circulation * physiology   MeSH
• Heart Failure * physiopathology   complications   therapy   MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH

AIMS: Pulmonary hypertension (PH) represents an important phenotype among the broader spectrum of patients with heart failure with preserved ejection fraction (HFpEF), but its mechanistic basis remains unclear. We hypothesized that activation of endothelin and adrenomedullin, two counterregulatory pathways important in the pathophysiology of PH, would be greater in HFpEF patients with worsening PH, and would correlate with the severity of haemodynamic derangements and limitations in aerobic capacity and cardiopulmonary reserve. METHODS AND RESULTS: Plasma levels of C-terminal pro-endothelin-1 (CT-proET-1) and mid-regional pro-adrenomedullin (MR-proADM), central haemodynamics, echocardiography, and oxygen consumption (VO2) were measured at rest and during exercise in subjects with invasively-verified HFpEF (n = 38) and controls free of HF (n = 20) as part of a prospective study. Plasma levels of CT-proET-1 and MR-proADM were highly correlated with one another (r = 0.89, P < 0.0001), and compared to controls, subjects with HFpEF displayed higher levels of each neurohormone at rest and during exercise. C-terminal pro-endothelin-1 and MR-proADM levels were strongly correlated with mean pulmonary artery (PA) pressure (r = 0.73 and 0.65, both P < 0.0001) and pulmonary capillary wedge pressure (r = 0.67 and r = 0.62, both P < 0.0001) and inversely correlated with PA compliance (r = -0.52 and -0.43, both P < 0.001). As compared to controls, subjects with HFpEF displayed right ventricular (RV) reserve limitation, evidenced by less increases in RV s' and e' tissue velocities, during exercise. Baseline CT-proET-1 and MR-proADM levels were correlated with worse RV diastolic reserve (ΔRV e', r = -0.59 and -0.67, both P < 0.001), reduced cardiac output responses to exercise (r = -0.59 and -0.61, both P < 0.0001), and more severely impaired peak VO2 (r = -0.60 and -0.67, both P < 0.0001). CONCLUSION: Subjects with HFpEF display activation of the endothelin and adrenomedullin neurohormonal pathways, the magnitude of which is associated with pulmonary haemodynamic derangements, limitations in RV functional reserve, reduced cardiac output, and more profoundly impaired exercise capacity in HFpEF. Further study is required to evaluate for causal relationships and determine if therapies targeting these counterregulatory pathways can improve outcomes in patients with the HFpEF-PH phenotype. CLINICAL TRIAL REGISTRATION: NCT01418248; https://clinicaltrials.gov/ct2/results? term=NCT01418248&Search=Search.

• Keywords
• Biomarker, Exercise, Heart failure, Pulmonary circulation,
• MeSH
• Pulmonary Artery physiology   MeSH
• Arterial Pressure physiology   MeSH
• Atrial Natriuretic Factor blood   MeSH
• Exercise physiology   MeSH
• Echocardiography methods   MeSH
• Endothelin-1 blood   MeSH
• Hemodynamics physiology   MeSH
• Middle Aged MeSH
• Humans MeSH
• Peptide Fragments blood   MeSH
• Hypertension, Pulmonary etiology   metabolism   physiopathology   MeSH
• Prospective Studies MeSH
• Cross-Sectional Studies MeSH
• Aged MeSH
• Oxygen Consumption physiology   MeSH
• Heart Failure complications   physiopathology   MeSH
• Case-Control Studies MeSH
• Stroke Volume physiology   MeSH
• Exercise Tolerance physiology   MeSH
• Check Tag
• Middle Aged MeSH
• Humans MeSH
• Male MeSH
• Aged MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Clinical Trial MeSH
• Research Support, Non-U.S. Gov't MeSH
• Research Support, N.I.H., Extramural MeSH
• Names of Substances
• Atrial Natriuretic Factor MeSH
• C-terminal proendothelin-1 MeSH Browser
• Endothelin-1 MeSH
• midregional pro-atrial natriuretic peptide, human MeSH Browser
• Peptide Fragments MeSH