Pilot Study of Endothelin Receptor Blockade in Heart Failure with Diastolic Dysfunction and Pulmonary Hypertension (BADDHY-Trial). Heart Lung Circ. 2017;26:433-441. [PMID: 27816421 DOI: 10.1016/j.hlc.2016.09.004]

Treg Cells Attenuate Pulmonary Venous Remodeling in PH-LHD via NLRC3 Signaling

BACKGROUND

Pulmonary venous remodeling is a key pathological feature of pulmonary hypertension associated with left heart disease (PH-LHD). This study aims to investigate the role of regulatory T (Treg) cells in this process.

METHODS

We used mouse models with transverse aortic constriction and cell depletion of Foxp3-DTR/tdTomato mice to examine Treg cells' function around pulmonary veins in PH-LHD in vivo. To confirm the effect of Nlrc3-/- Treg cells on PH-LHD, we utilized 3 mouse models: Nlrc3 knockout mice, athymic mice, and endothelial cell lineage tracing Cdh5CreERT2+/--mT/mG+/- mice. The interaction proteins and signaling pathways of Treg cells during endothelial-to-mesenchymal transition were elucidated by protein docking prediction, coimmunoprecipitation and cocultivation of Treg cells with venous endothelial cells.

RESULTS

Treg cells were abundant around pulmonary veins of transverse aortic constriction-induced PH-LHD and were essential for promoting inflammation resolution and inhibiting pulmonary venous remodeling. Nlrc3 expression was reduced in mice and patients with PH-LHD. NLRC3 (nucleotide-oligomerization domain-like receptor family CARD domain containing 3) deficiency inhibited Treg cell proliferation and impaired their immunosuppressive and endothelial-to-mesenchymal transition-protective effects. Mechanistically, NLRC3 interacted with TRAM (TRIF-related adaptor molecule) and regulated IRF3/NF-κB (nuclear factor-κB) p65 signaling in CD4+ T cells. NLRC3-deficient Treg cells promoted IL (interleukin)-18 expression through IRF3/NF-κB p65 signaling, and thus IL-18 secretion activated endothelial RTK (receptor tyrosine kinase) signaling, favoring endothelial-to-mesenchymal transition progression in pulmonary veins and PH-LHD progress. This process was reversible with IL-18 binding protein in vivo.

CONCLUSIONS

NLRC3 is crucial for Treg cells to prevent pulmonary venous remodeling in PH-LHD, primarily by modulating IL-18 secretion, which inhibits endothelial-to-mesenchymal transition and thereby improves disease progression and prognosis.

Pulmonary Hypertension: Pharmacological and Non-Pharmacological Therapies

Pulmonary hypertension (PH) is a severe and chronic disease characterized by increased pulmonary vascular resistance and remodeling, often precipitating right-sided heart dysfunction and death. Although the condition is progressive and incurable, current therapies for the disease focus on multiple different drugs and general supportive therapies to manage symptoms and prolong survival, ranging from medications more specific to pulmonary arterial hypertension (PAH) to exercise training. Moreover, there are multiple studies exploring novel experimental drugs and therapies including unique neurostimulation, to help better manage the disease. Here, we provide a narrative review focusing on current PH treatments that target multiple underlying biochemical mechanisms, including imbalances in vasoconstrictor-vasodilator and autonomic nervous system function, inflammation, and bone morphogenic protein (BMP) signaling. We also focus on the potential of novel therapies for managing PH, focusing on multiple types of neurostimulation including acupuncture. Lastly, we also touch upon the disease's different subgroups, clinical presentations and prognosis, diagnostics, demographics, and cost.

New Therapies in Outpatient Pulmonary Medicine

Newer medications and devices, as well as greater understanding of the benefits and limitations of existing treatments, have led to expanded treatment options for patients with lung disease. Treatment advances have led to improved outcomes for patients with asthma, chronic obstructive pulmonary disease, interstitial lung disease, pulmonary hypertension, and cystic fibrosis. The risks and benefits of available treatments are substantially variable within these heterogeneous disease groups. Defining the role of newer therapies mandates both an understanding of these disorders and overall treatment approaches. This section will review general treatment approaches in addition to focusing on newer therapies for these conditions..

Management of Pulmonary Hypertension in the Context of Heart Failure with Preserved Ejection Fraction

PURPOSE OF REVIEW

To review the current evidence and modalities for treating pulmonary hypertension (PH) in heart failure with preserved ejection fraction (HFpEF).

RECENT FINDINGS

In recent years, several therapies have been developed that improve morbidity in HFpEF, though these studies have not specifically studied patients with PF-HFpEF. Multiple trials of therapies specifically targeting the pulmonary vasculature such as phosphodiesterase (PDE) inhibitors, prostacyclin analogs, endothelin receptor antagonists (ERA), and soluble guanylate cyclase stimulators have also been conducted. However, these therapies demonstrated lack of consistency in improving hemodynamics or functional outcomes in PH-HFpEF. There is limited evidence to support the use of pulmonary vasculature-targeting therapies in PH-HFpEF. The mainstay of therapy remains the treatment of the underlying HFpEF condition. There is emerging evidence that newer HF therapies such as sodium-glucose transporter 2 inhibitors and angiotensin-receptor-neprilysin inhibitors are associated with improved hemodynamics and quality of life of patients with PH-HFpEF. There is also a growing realization that more robust phenotyping PH and right ventricular (RV) function may hold promise for therapeutic strategies for patients with PH-HFpEF.

Biomarkers Correspond with Echocardiographic Phenotypes in Heart Failure with Preserved Ejection Fraction: A Secondary Analysis of the RELAX Trial

Background

Little is known about the relationship between structural phenotypes in in heart failure with preserved ejection fraction (HFpEF) and cardiac biomarkers. We used cluster analysis to identify cardiac structural phenotypes and their relationships to biomarkers in HFpEF.

Methods and results

Latent class analysis (LCA) was applied to echocardiographic data including left atrial enlargement (LAE), diastolic dysfunction (DD), E/e', EF≤55%, and right ventricular dysfunction from 216 patients enrolled in the RELAX trial. Three structural phenotypes were identified. Phenotype A had the most grade II DD. Phenotype B had the most grade III DD, worst LAE, elevated E/e' and right ventricular dysfunction. Phenotype C had the least DD and moderate LAE. Phenotypes B and C had prevalent atrial fibrillation (AF). Phenotype B patients had increased carboxy-terminal telopeptide of collagen type I (CITP), cystatin-c (CYSTC), endothelin-1 (ET1), NT-proBNP, and high-sensitivity troponin I (TNI). Type A had the next highest CITP and CYSTC levels while Type C had next highest NT-proBNP.

Conclusions

Structural HFpEF phenotypes demonstrated different characteristics including cardiac biomarkers. These findings may help explain phenotype-specific differences in natural history and prognosis, and they may represent phenotype-specific pathophysiology that could be amenable to targeted therapy.

Advance in the pharmacological and comorbidities management of heart failure with preserved ejection fraction: evidence from clinical trials

The prevalence of heart failure with preserved ejection fraction (HFpEF) accounts for approximately 50% of the total heart failure population, and with the aging of the population and the increasing prevalence of hypertension, obesity, and type 2 diabetes (T2DM), the incidence of HFpEF continues to rise and has become the most common subtype of heart failure. Compared with heart failure with reduced ejection fraction, HFpEF has a more complex pathophysiology and is more often associated with hypertension, T2DM, obesity, atrial fibrillation, renal insufficiency, pulmonary hypertension, obstructive sleep apnea, and other comorbidities. HFpEF has generally been considered a syndrome with high phenotypic heterogeneity, and no effective treatments have been shown to reduce mortality to date. Diuretics and comorbidity management are traditional treatments for HFpEF; however, they are mostly empirical due to a lack of clinical evidence in the setting of HFpEF. With the EMPEROR-Preserved and DELIVER results, sodium-glucose cotransporter 2 inhibitors become the first evidence-based therapies to reduce rehospitalization for heart failure. Subgroup analyses of the PARAGON-HF, TOPCAT, and CHARM-Preserved trials suggest that angiotensin receptor-neprilysin inhibitors, spironolactone, and angiotensin II receptor blockers may be beneficial in patients at the lower end of the ejection fraction spectrum. Other potential pharmacotherapies represented by non-steroidal mineralocorticoid receptor antagonists finerenone and antifibrotic agent pirfenidone also hold promise for the treatment of HFpEF. This article intends to review the clinical evidence on current pharmacotherapies of HFpEF, as well as the comorbidities management of atrial fibrillation, hypertension, T2DM, obesity, pulmonary hypertension, renal insufficiency, obstructive sleep apnea, and iron deficiency, to optimize the clinical management of HFpEF.

Post-Capillary Pulmonary Hypertension: Clinical Review

Pulmonary hypertension (PH) caused by left heart disease, also known as post-capillary PH, is the most common etiology of PH. Left heart disease due to systolic dysfunction or heart failure with preserved ejection fraction, valvular heart disease, and left atrial myopathy due to atrial fibrillation are causes of post-capillary PH. Elevated left-sided filling pressures cause pulmonary venous congestion due to backward transmission of pressures and post-capillary PH. In advanced left-sided heart disease or valvular heart disease, chronic uncontrolled venous congestion may lead to remodeling of the pulmonary arterial system, causing combined pre-capillary and post-capillary PH. The hemodynamic definition of post-capillary PH includes a mean pulmonary arterial pressure > 20 mmHg, pulmonary vascular resistance < 3 Wood units, and pulmonary capillary wedge pressure > 15 mmHg. Echocardiography is important in the identification and management of the underlying cause of post-capillary PH. Management of post-capillary PH is focused on the treatment of the underlying condition. Strategies are geared towards pharmacotherapy and guideline-directed medical therapy for heart failure, surgical or percutaneous management of valvular disorders, and control of modifiable risk factors and comorbid conditions. Referral to centers with advanced heart and pulmonary teams has shown to improve morbidity and mortality. There is emerging interest in the use of targeted agents classically used in pulmonary arterial hypertension, but current data remain limited and conflicting. This review aims to serve as a comprehensive summary of postcapillary PH and its etiologies, pathophysiology, diagnosis, and management, particularly as it pertains to advanced heart failure.

Is Pulmonary Capillary Wedge Pressure a Reliable Indicator of Postcapillary Pulmonary Hypertension?

Although current pulmonary hypertension (PH) guidelines recommend a pulmonary capillary wedge pressure (PCWP) >15 mm Hg for the detection of a postcapillary component, the rationale of this recommendation may not be quite compatible with the peculiar hemodynamics of PH. We hypothesize that a high PCWP alone does not necessarily indicate left-sided disease, and this diagnosis can be improved using left ventricle transmural pressure difference (∆ PTM). In this 2-center, retrospective, observational study, we enrolled 1,070 patients with PH who underwent heart catheterization, with the final study population comprising 961 cases. ∆ PTM was calculated as PCWP minus right atrial pressure. The patients with group II PH had significantly higher ∆ PTM values (12.6 ± 6.6 mm Hg) compared with the other groups (1.1 ± 4.8 in group I, 12.4 ± 6.6 in group II, 2.5 ± 6.4 in group III, and 0.8 ± 8.0 in group IV, p <0.001) despite overlapping PCWP values. A ∆ PTM cutoff of 7 mm Hg identifies left heart disease when PCWP is >15 (area under curve 0.825, 95% confidence interval 0.784 to 0.866, p <0.001). Five-year mortality was significantly higher in patients with high ∆ PTM and PCWP subgroups compared with low ∆ PTM plus high PCWP (26.1% vs 18.5%, p = 0.027) and low ∆ PTM and PCWP subgroups (26.1% vs 15.6%, p <0.001). ∆ PTM has supplementary discriminatory power in distinguishing patients with and without postcapillary PH. In conclusion, a new approach utilizing ∆ PTM may improve our understanding of PH pathophysiology and may identify a subpopulation that may potentially benefit from PH-specific treatments.

[Pulmonary hypertension associated with left heart disease (group 2)]

Pulmonary hypertension associated with left heart disease (PH-LHD) corresponds to group two of pulmonary hypertension according to clinical classification. Haemodynamically, this group includes isolated post-capillary pulmonary hypertension (IpcPH) and combined post- and pre-capillary pulmonary hypertension (CpcPH). PH-LHD is defined by an mPAP > 20 mmHg and a PAWP > 15 mmHg, pulmonary vascular resistance (PVR) with a cut-off value of 2 Wood Units (WU) is used to differentiate between IpcPH and CpcPH. A PVR greater than 5 WU indicates a dominant precapillary component. PH-LHD is the most common form of pulmonary hypertension, the leading cause being left heart failure with preserved (HFpEF) or reduced ejection fraction (HFmrEF, HFrEF), valvular heart disease and, less commonly, congenital heart disease. The presence of pulmonary hypertension is associated with increased symptom burden and poorer outcome across the spectrum of left heart disease. Differentiating between group 1 pulmonary hypertension with cardiac comorbidities and PH-LHD, especially due to HFpEF, is a particular challenge. Therapeutically, no general recommendation for the use of PDE5 inhibitors in HFpEF-associated CpcPH can be made at this time. There is currently no reliable rationale for the use of PAH drugs in IpcPH, nor is therapy with endothelin receptor antagonists or prostacyclin analogues recommended for all forms of PH-LHD.

Pulmonary Hypertension in Left Heart Diseases: Pathophysiology, Hemodynamic Assessment and Therapeutic Management

Pulmonary hypertension (PH) associated with left heart diseases (PH-LHD), also termed group 2 PH, represents the most common form of PH. It develops through the passive backward transmission of elevated left heart pressures in the setting of heart failure, either with preserved (HFpEF) or reduced (HFrEF) ejection fraction, which increases the pulsatile afterload of the right ventricle (RV) by reducing pulmonary artery (PA) compliance. In a subset of patients, progressive remodeling of the pulmonary circulation resulted in a pre-capillary phenotype of PH, with elevated pulmonary vascular resistance (PVR) further increasing the RV afterload, eventually leading to RV-PA uncoupling and RV failure. The primary therapeutic objective in PH-LHD is to reduce left-sided pressures through the appropriate use of diuretics and guideline-directed medical therapies for heart failure. When pulmonary vascular remodeling is established, targeted therapies aiming to reduce PVR are theoretically appealing. So far, such targeted therapies have mostly failed to show significant positive effects in patients with PH-LHD, in contrast to their proven efficacy in other forms of pre-capillary PH. Whether such therapies may benefit some specific subgroups of patients (HFrEF, HFpEF) with specific hemodynamic phenotypes (post- or pre-capillary PH) and various degrees of RV dysfunction still needs to be addressed.

Management of heart failure with preserved ejection fraction: from neurohormonal antagonists to empagliflozin

Heart failure with preserved ejection fraction (HFpEF) is a highly prevalent syndrome with multifaceted pathophysiology. All approaches to neurohormonal modulation were shown not to improve survival in HFpEF, despite their well-established efficacy in heart failure with reduced ejection fraction (HFrEF). This might be attributed to suboptimal study design, inadequate diagnostic criteria, or statistical power, but is also likely to reflect a lack of consideration for its clinical heterogeneity. The attention then shifted to the phenotypic heterogeneity of HFpEF, with the ultimate goal of developing therapies tailored to individual patient phenotypes. Recently, the sodium-glucose co-transporter-2 inhibitor (SGLT2i) empagliflozin has been found to reduce the combined risk of cardiovascular death or hospitalization for HF in patients with HFpEF, a result driven by a reduction in HF hospitalizations. This paper recapitulates the journey from the failure of trials on neurohormonal antagonists to the attempts of personalized approaches and the new perspectives of SGLT2i therapy for HFpEF.

Updates in the Pharmacotherapy of Pulmonary Hypertension in Patients with Heart Failure with Preserved Ejection Fraction

Pulmonary hypertension (PH) associated with left heart disease (LHD) is a complex cardiopulmonary condition where a variable degree of pulmonary congestion, arterial vasoconstriction and vascular remodeling can lead to PH and right heart strain. Right heart dysfunction has a significant prognostic impact on these patients. Therefore, preserving right ventricular (RV) function is an important treatment goal. However, the treatment of PH in patients with left heart disease has produced conflicting evidence. The transition from pure LHD to LHD with PH is a continuum and clinically challenging. The heart failure with preserved ejection fraction (HFpEF) patient population is heterogeneous when it comes to PH and RV function. Appropriate clinical and hemodynamic phenotyping of patients with HFpEF and concomitant PH is paramount to making the appropriate treatment decision. This manuscript will summarize the current evidence for the use of pulmonary arterial vasodilators in patients with HFpEF.

Left Ventricular Fibrosis Assessment by Native T1, ECV, and LGE in Pulmonary Hypertension Patients

Cardiac magnetic resonance imaging (MRI) is emerging as an alternative to right heart catheterization for the evaluation of pulmonary hypertension (PH) patients. The aim of this study was to compare cardiac MRI-derived left ventricle fibrosis indices between pre-capillary PH (PrePH) and isolated post-capillary PH (IpcPH) patients and assess their associations with measures of ventricle function. Global and segmental late gadolinium enhancement (LGE), longitudinal relaxation time (native T1) maps, and extracellular volume fraction (ECV) were compared among healthy controls (N = 25; 37% female; 52 ± 13 years), PH patients (N = 48; 60% female; 60 ± 14 years), and PH subgroups (PrePH: N = 29; 65% female; 55 ± 12 years, IpcPH: N = 19; 53% female; 66 ± 13 years). Cardiac cine measured ejection fraction, end diastolic, and end systolic volumes and were assessed for correlations with fibrosis. LGE mural location was qualitatively assessed on a segmental basis for all subjects. PrePH patients had elevated (apical-, mid-antero-, and mid-infero) septal left ventricle native T1 values (1080 ± 74 ms, 1077 ± 39 ms, and 1082 ± 47 ms) compared to IpcPH patients (1028 ± 53 ms, 1046 ± 36 ms, 1051 ± 44 ms) (p < 0.05). PrePH had a higher amount of insertional point LGE (69%) and LGE patterns characteristic of non-vascular fibrosis (77%) compared to IpcPH (37% and 46%, respectively) (p < 0.05; p < 0.05). Assessment of global LGE, native T1, and ECV burdens did not show a statistically significant difference between PrePH (1.9 ± 2.7%, 1056.2 ± 36.3 ms, 31.2 ± 3.7%) and IpcPH (2.7 ± 2.7%, 1042.4 ± 28.1 ms, 30.7 ± 4.7%) (p = 0.102; p = 0.229 p = 0.756). Global native T1 and ECV were higher in patients (1050.9 ± 33.8 and 31.0 ± 4.1%) than controls (28.2 ± 3.7% and 1012.9 ± 29.4 ms) (p < 0.05). Cardiac MRI-based tissue characterization may augment understanding of cardiac involvement and become a tool to facilitate PH patient classification.

Heart Failure with Preserved Ejection Fraction and Pulmonary Hypertension: Focus on Phosphodiesterase Inhibitors

Pulmonary hypertension (PH) is common in patients with heart failure with preserved ejection fraction (HFpEF). A chronic increase in mean left atrial pressure leads to passive remodeling in pulmonary veins and capillaries and modest PH (isolated postcapillary PH, Ipc-PH) and is not associated with significant right ventricular dysfunction. In approximately 20% of patients with HFpEF, "precapillary" alterations of pulmonary vasculature occur with the development of the combined pre- and post-capillary PH (Cpc-PH), pertaining to a poor prognosis. Current data indicate that pulmonary vasculopathy may be at least partially reversible and thus serves as a therapeutic target in HFpEF. Pulmonary vascular targeted therapies, including phosphodiesterase (PDE) inhibitors, may have a valuable role in the management of patients with PH-HFpEF. In studies of Cpc-PH and HFpEF, PDE type 5 inhibitors were effective in long-term follow-up, decreasing pulmonary artery pressure and improving RV contractility, whereas studies of Ipc-PH did not show any benefit. Randomized trials are essential to elucidate the actual value of PDE inhibition in selected patients with PH-HFpEF, especially in those with invasively confirmed Cpc-PH who are most likely to benefit from such treatment.

Corrected MRI Pulmonary Transit Time for Identification of Combined Precapillary and Postcapillary Pulmonary Hypertension in Patients With Left Heart Disease

BACKGROUND

The identification of combined precapillary and postcapillary pulmonary hypertension (CpcPH) in patients with pulmonary hypertension (PH) due to left heart disease (LHD) can influence therapy and outcome and is currently based on invasively determined hemodynamic parameters.

PURPOSE

To investigate the diagnostic value of MRI-derived corrected pulmonary transit time (PTTc) in PH-LHD sub-grouped according to hemodynamic phenotypes.

STUDY TYPE

Prospective observational study.

POPULATION

A total of 60 patients with PH-LHD (18 with isolated postcapillary PH [IpcPH] and 42 with CpcPH), and 33 healthy subjects.

FIELD STRENGTH/SEQUENCE

A 3.0 T/balanced steady-state free precession cine and gradient echo-train echo planar pulse first-pass perfusion.

ASSESSMENT

In patients, right heart catheterization (RHC) and MRI were performed within 30 days. Pulmonary vascular resistance (PVR) was used as the diagnostic "reference standard." The PTTc was calculated as the time interval between the peaks of the biventricular signal-intensity/time curve and corrected for heart rate. PTTc was compared between patient groups and healthy subjects and its relationship to PVR assessed. The diagnostic accuracy of PTTc for distinguishing IpcPH and CpcPH was determined.

STATISTICAL TESTS

Student's t-test, Mann-Whitney U-test, linear and logistic regression analysis, and receiver-operating characteristic curves. Significance level: P < 0.05.

RESULTS

PTTc was significantly prolonged in CpcPH compared with IpcPH and normal controls (17.28 ± 7.67 vs. 8.82 ± 2.55 vs. 6.86 ± 2.11 seconds), and in IpcPH compared with normal controls (8.82 ± 2.55 vs. 6.86 ± 2.11 seconds). Prolonged PTTc was significantly associated with increased PVR. Furthermore, PTTc was a significantly independent predictor of CpcPH (odds ratio: 1.395, 95% confidence interval: 1.071-1.816). The area under curve was 0.852 at a cut-off value of 11.61 seconds for PTTc to distinguish between CpcPH and IpcPH (sensitivity 71.43% and specificity 94.12%).

DATA CONCLUSION

PTTc may be used to identify CpcPH. Our findings have potential to improve selection for invasive RHC for PH-LHD patients.

EVIDENCE LEVEL

3 TECHNICAL EFFICACY: Stage 2.

Sacubitril/valsartan affects pulmonary arterial pressure in heart failure with preserved ejection fraction and pulmonary hypertension

AIMS

Prior studies have not fully characterized the haemodynamic effects of the angiotensin receptor-neprilysin inhibitor (ARNI) sacubitril/valsartan in heart failure with preserved ejection fraction and pulmonary hypertension (HFpEF-PH). The aim of the Treatment of PH With Angiotensin II Receptor Blocker and Neprilysin Inhibitor in HFpEF Patients With CardioMEMS Device (ARNIMEMS-HFpEF) study is to assess pulmonary artery pressure (PAP) dynamics by means of implanted PAP monitors in patients with HFpEF-PH treated with sacubitril/valsartan.

METHODS AND RESULTS

This single-arm, investigator-initiated, interventional study included 14 consecutive ambulatory symptomatic HFpEF-PH patients who underwent CardioMEMS implantation prior to enrolment [mean ejection fraction 60.4 ± 7.2%, baseline mean PAP (mPAP) 33.9 ± 7.6 mmHg]. Daily PAP values were examined during three periods: a 6 week period after CardioMEMS implantation and before sacubitril/valsartan treatment (pre-ARNI), a 6 week period with sacubitril/valsartan treatment (ARNI ON), and a 6 week period of sacubitril/valsartan withdrawal (ARNI OFF). The primary endpoint was change in mPAP with and without sacubitril/valsartan. Secondary endpoints included changes in 6 min walking distance, B-line sum in lung ultrasound, and quality of life (QoL). During the study period, 1717 mPAP measurements were recorded. Between pre-ARNI vs. ARNI ON, mPAP significantly declined by -4.99 mmHg [95% confidence interval (CI) -5.55 to -4.43]. Between ARNI ON vs. ARNI OFF, mPAP significantly increased by +2.84 mmHg [95% CI +2.26 to +3.42]. Between pre-ARNI vs. ARNI ON, we found an improvement in 6 min walking distance, B-lines, and QoL. Mean loop diuretic management did not differ between periods.

CONCLUSIONS

Sacubitril/valsartan significantly reduced mPAP in patients with HFpEF-PH, independent of loop diuretic management, together with improvement in functional capacity, lung congestion, and QoL. Sacubitril/valsartan may be a therapeutic alternative in HFpEF-PH.

Left Heart Disease-Related Pulmonary Hypertension

Pulmonary hypertension (PH) due to left heart disease (LHD; group 2 PH) is a common complication of heart failure with reduced ejection fraction and heart failure with preserved ejection fraction and is often related to disease severity and duration of these diseases. PH due to LHD is associated with negative impact on outcomes in addition to worse symptoms and exercise capacity. Risk factors for group 2 PH are older age, hypertension, atrial fibrillation, and features of metabolic syndrome. The main mechanisms for group 2 PH are believed to be vascular remodeling secondary to sustained elevated intravascular pressure.

Impaired pulmonary vasomotor control in exercising swine with multiple comorbidities

Pulmonary hypertension is common in heart failure with preserved ejection fraction (HFpEF). Here, we tested the hypothesis that comorbidities [diabetes mellitus (DM, streptozotocin), hypercholesterolemia (HC, high-fat diet) and chronic kidney disease (CKD, renal microembolization)] directly impair pulmonary vasomotor control in a DM + HC + CKD swine model. 6 months after induction of DM + HC + CKD, pulmonary arterial pressure was similar in chronically instrumented female DM + HC + CKD (n = 19) and Healthy swine (n = 18). However, cardiac output was lower both at rest and during exercise, implying an elevated pulmonary vascular resistance (PVR) in DM + HC + CKD swine (153 ± 10 vs. 122 ± 9 mmHg∙L^-1∙min∙kg). Phosphodiesterase 5 inhibition and endothelin receptor antagonism decreased PVR in DM + HC + CKD (- 12 ± 12 and - 22 ± 7 mmHg∙L^-1∙min∙kg) but not in Healthy swine (- 1 ± 12 and 2 ± 14 mmHg∙L^-1∙min∙kg), indicating increased vasoconstrictor influences of phosphodiesterase 5 and endothelin. Inhibition of nitric oxide synthase produced pulmonary vasoconstriction that was similar in Healthy and DM + HC + CKD swine, but unmasked a pulmonary vasodilator effect of endothelin receptor antagonism in Healthy (- 56 ± 26 mmHg∙L^-1∙min∙kg), whereas it failed to significantly decrease PVR in DM + HC + CKD, indicating loss of nitric oxide mediated inhibition of endothelin in DM + HC + CKD. Scavenging of reactive oxygen species (ROS) had no effect on PVR in either Healthy or DM + HC + CKD swine. Cardiovascular magnetic resonance imaging, under anesthesia, showed no right ventricular changes. Finally, despite an increased contribution of endogenous nitric oxide to vasomotor tone regulation in the systemic vasculature, systemic vascular resistance at rest was higher in DM + HC + CKD compared to Healthy swine (824 ± 41 vs. 698 ± 35 mmHg∙L^-1∙min∙kg). ROS scavenging induced systemic vasodilation in DM + HC + CKD, but not Healthy swine. In conclusion, common comorbidities directly alter pulmonary vascular control, by enhanced PDE5 and endothelin-mediated vasoconstrictor influences, well before overt left ventricular backward failure or pulmonary hypertension develop.

Management of Pulmonary Hypertension in Left Heart Disease

Pulmonary hypertension due to left heart diseases (PH-LHD) is the most prevalent form of pulmonary hypertension. It frequently complicates heart failure with reduced ejection fraction (HFrEF) or preserved ejection fraction (HFpEF) and negatively impacts prognosis, particularly when a precapillary component is present.

PH-LHD is distinctive from pulmonary arterial hypertension (PAH) even though both conditions may share some common characteristics. In addition, the mechanisms involved in the development of a precapillary component are yet to be fully clarified, in particular in PH due to HFpEF.

Several studies have been exploring PAH pathways as potential therapies for PH-LHD, but no PAH-approved drug has demonstrated efficacy in PH-LHD. Rather, some classes of drugs, such as endothelin-receptor antagonists or prostacycline-analogues, have been found to be harmful in patients with HF. Therefore, at present, the only established treatments for PH-LHD are those that target the heart as recommended in the international guidelines for HF. Based on current knowledge, off-label prescription of PAH-approved drugs in PH-LHD patients must be strongly discouraged.

Pulmonary Hypertension in Left Heart Disease

Pulmonary hypertension is common in left heart disease and is related most commonly to passive back transmission of elevated left atrial pressures. Some patients, however, may develop pulmonary vascular remodeling superimposed on their left-sided heart disease. This review provides a contemporary appraisal of existing criteria to diagnose a precapillary component to pulmonary hypertension in left heart disease as well as discusses etiologies, management issues, and future directions.

Pulmonary Hypertension in Patients With Heart Failure With Mid-Range Ejection Fraction

Pulmonary hypertension (PH) is common in patients with heart failure (HF). The role of PH in patients with HF with reduced (HFrEF) and preserved (HFpEF) left ventricular ejection fraction (LVEF) has been extensively characterized during the last years. In contrast, the pathophysiology of HF with mid-range LVEF (HFmrEF), and in particular the role of PH in this context, are largely unknown. There is a paucity of data in this field, and the prevalence of PH, the underlying mechanisms, and the optimal therapy are not well-defined. Although often studied together there is increasing evidence that despite similarities with both HFrEF and HFpEF, HFmrEF also differs from both entities. The present review provides a summary of the current concepts of the mechanisms and clinical impact of PH in patients with HFmrEF, a proposal for the non-invasive and invasive diagnostic approach required to define the pathophysiology of PH and its management, and a discussion of future directions based on insights from mechanistic studies and randomized trials. We also provide an outlook regarding gaps in evidence, future clinical challenges, and research opportunities.

Right Heart Phenotype in Heart Failure With Preserved Ejection Fraction

The health burden of heart failure with preserved ejection fraction is increasingly recognized. Despite improvements in diagnostic algorithms and established knowledge on the clinical trajectory, effective treatment options for heart failure with preserved ejection fraction remain limited, mainly because of the high mechanistic heterogeneity. Diagnostic scores, big data, and phenomapping categorization are proposed as key steps needed for progress. In the meantime, advancements in imaging techniques combined to high-fidelity pressure signaling analysis have uncovered right ventricular dysfunction as a mediator of heart failure with preserved ejection fraction progression and as major independent determinant of poor outcome. This review summarizes the current understanding of the pathophysiology of right ventricular dysfunction in heart failure with preserved ejection fraction covering the different right heart phenotypes and offering perspectives on new treatments targeting the right ventricle in its function and geometry.

Endothelin receptor antagonists for pulmonary arterial hypertension

BACKGROUND

Pulmonary arterial hypertension is a devastating disease that leads to right heart failure and premature death. Endothelin receptor antagonists have shown efficacy in the treatment of pulmonary arterial hypertension.

OBJECTIVES

To evaluate the efficacy of endothelin receptor antagonists (ERAs) in pulmonary arterial hypertension.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, and the reference sections of retrieved articles. The searches are current as of 4 November 2020.

SELECTION CRITERIA

We included randomised trials and quasi-randomised trials involving participants with pulmonary arterial hypertension.

DATA COLLECTION AND ANALYSIS

Two of five review authors selected studies, extracted data and assessed study quality according to established criteria. We used standard methods expected by Cochrane. The primary outcomes were exercise capacity (six-minute walk distance, 6MWD), World Health Organization (WHO) or New York Heart Association (NYHA) functional class, Borg dyspnoea scores and dyspnoea-fatigue ratings, and mortality.

MAIN RESULTS

We included 17 randomised controlled trials involving a total of 3322 participants. Most trials were of relatively short duration (12 weeks to six months). Sixteen trials were placebo-controlled, and of these nine investigated a non-selective ERA and seven a selective ERA.   We evaluated two comparisons in the review: ERA versus placebo and ERA versus phosphodiesterase type 5 (PDE5) inhibitor. The abstract focuses on the placebo-controlled trials only and presents the pooled results of selective and non-selective ERAs. After treatment, participants receiving ERAs could probably walk on average 25.06 m (95% confidence interval (CI) 17.13 to 32.99 m; 2739 participants; 14 studies; I2 = 34%, moderate-certainty evidence) further than those receiving placebo in a 6MWD. Endothelin receptor antagonists probably improved more participants' WHO functional class (odds ratio (OR) 1.41, 95% CI 1.16 to 1.70; participants = 3060; studies = 15; I2 = 5%, moderate-certainty evidence) and probably lowered the odds of functional class deterioration (OR 0.43, 95% CI 0.26 to 0.72; participants = 2347; studies = 13; I2 = 40%, moderate-certainty evidence) compared with placebo. There may be a reduction in mortality with ERAs (OR 0.78, 95% CI 0.58, 1.07; 2889 participants; 12 studies; I2 = 0%, low-certainty evidence), and pooled data suggest that ERAs probably improve cardiopulmonary haemodynamics and may reduce Borg dyspnoea score in symptomatic patients. Hepatic toxicity was not common, but may be increased by ERA treatment from 37 to 67 (95% CI 34 to 130) per 1000 over 25 weeks of treatment (OR 1.88, 95% CI 0.91 to 3.90; moderate-certainty evidence). Although ERAs were well tolerated in this population, several cases of irreversible liver failure caused by sitaxsentan have been reported, which led the licence holder for sitaxsentan to withdraw the product from all markets worldwide.  As planned, we performed subgroup analyses comparing selective and non-selective ERAs, and with the exception of mean pulmonary artery pressure, did not detect any clear subgroup differences for any outcome.

AUTHORS' CONCLUSIONS

For people with pulmonary arterial hypertension with WHO functional class II and III, endothelin receptor antagonists probably increase exercise capacity, improve WHO functional class, prevent WHO functional class deterioration, result in favourable changes in cardiopulmonary haemodynamic variables compared with placebo. However, they are less effective in reducing dyspnoea and mortality. The efficacy data were strongest in those with idiopathic pulmonary hypertension. The irreversible liver failure caused by sitaxsentan and its withdrawal from global markets emphasise the importance of hepatic monitoring in people treated with ERAs. The question of the effects of ERAs on pulmonary arterial hypertension has now likely been answered.. The combined use of ERAs and phosphodiesterase inhibitors may provide more benefit in pulmonary arterial hypertension; however, this needs to be confirmed in future studies.

Practice patterns of pulmonary hypertension secondary to left heart disease among pediatric pulmonary hypertension providers

Development of pulmonary hypertension (PH) in patients with left side heart disease (LHD) is a predictor of poor prognosis. The use of pulmonary vasodilators in PH associated with LHD (PH-LHD) is controversial. In this study, we describe the practice patterns regarding the use of pulmonary vasodilators in PH-LHD among a group of international pediatric PH specialists. A survey was distributed to the members of three pediatric PH networks: PPHNet, PVRI, and REHIPED. The survey queried participants on the rationale, indications, and contraindications of the use of pulmonary vasodilators in children with PH-LHD. Forty-seven PH specialists from 39 PH centers completed the survey. Participants included PH specialists from North America (57%), South America (15%), and Europe (19%). The majority of participants (74%) recommended the use of pulmonary vasodilators only in patients with combined pre-capillary and post-capillary pulmonary hypertension. Participants required the presence of clinical symptoms or signs of heart failure (68%) or right ventricular dysfunction by echocardiography (51%) in order to recommend pulmonary vasodilator therapy. There was no agreement regarding hemodynamic criteria used to recommend pulmonary vasodilators or the etiologies of LHD considered contraindications for using pulmonary vasodilators to manage PH-LHD. Of the available PH-targeted drugs, most participants preferred the use of phosphodiesterase-5-inhibitors for this indication. In conclusion, the practice of recommending pulmonary vasodilators in PH-LHD is highly variable among international pediatric PH specialists. Most specialists of those surveyed (57% in North America) would consider the use of pulmonary vasodilators in PH-LHD only if pre-capillary pulmonary hypertension and right ventricular dysfunction are present.

Sex-Related Differences in Dynamic Right Ventricular-Pulmonary Vascular Coupling in Heart Failure With Preserved Ejection Fraction

BACKGROUND

Right ventricular (RV) dysfunction is associated with poorer outcomes in heart failure with preserved ejection fraction (HFpEF). Although female subjects are more likely to have HFpEF, male subjects have worse prognosis and resting RV function. The contribution of dynamic RV-pulmonary arterial (RV-PA) coupling between sex and its impact on peak exercise capacity (VO₂) in HFpEF is not known.

RESEARCH QUESTION

The goal of this study was to investigate the differential effects of sex on RV-PA coupling during maximum incremental exercise in patients with HFpEF.

STUDY DESIGN AND METHODS

This study examined rest and exercise invasive pulmonary hemodynamics in 22 male patients with HFpEF and 27 female patients with HFpEF. To further investigate the discrepancy in RV-PA response between sex, 26 age-matched control subjects (11 male subjects and 15 female subjects) were included. Single beat analysis of RV pressure waveforms was used to determine the end-systolic elastance (Ees) and pulmonary arterial elastance. RV-PA coupling was determined as the ratio of end-systolic elastance/PA elastance.

RESULTS

Both HFpEF groups experienced decreased peak VO₂ (% predicted). However, male patients with HFpEF experienced a greater decrement in peak VO₂ compared with female patients (58 ± 16% vs 70 ± 15%; P < .05). Male patients with HFpEF had a more pronounced increase in RV afterload, Ea (1.8 ± 0.6 mm Hg/mL/m² vs 1.3 ± 0.4 mm Hg/mL/m²; P < .05) and failed to increase RV contractility during exercise, resulting in dynamic RV-PA uncoupling (0.9 ± 0.4 vs 1.2 ± 0.4; P < .05) and subsequent reduced stroke volume index augmentation. In contrast, female patients with HFpEF were able to augment RV contractility in the face of increasing afterload, preserving RV-PA coupling during exercise.

INTERPRETATION

Male patients with HFpEF were more compromised regarding dynamic RV-PA uncoupling and reduced peak VO₂ compared with female patients. This finding was driven by both RV contractile impairment and afterload mismatch. In contrast, female patients with HFpEF had preserved RV-PA coupling during exercise and better peak exercise VO₂ compared with male patients with HFpEF.

The Diagnostic and Therapeutic Value of Multimarker Analysis in Heart Failure. An Approach to Biomarker-Targeted Therapy

Background: Heart failure is a pathophysiological state, which is still associated with high morbidity and mortality despite established therapies. Diverse well-known biomarkers fail to assess the variety of individual pathophysiology in the context of heart failure. Methods: An analysis of prospective, multimarker-specific therapeutic approaches to heart failure based on studies in current literature was performed. A total of 159 screened publications in the field of biomarkers in heart failure were hand-selected and found to be eligible for this study by a team of experts. Results: Established biomarkers of the inflammatory axis, matrix remodeling, fibrosis and oxidative stress axis, as well as potential therapeutic interventions were investigated. Interaction with end organs, such as cardio-hepatic, cardio-renal and cardio-gastrointestinal interactions show the complexity of the syndrome and could be of further therapeutic value. MicroRNAs are involved in a wide variety of physiologic and pathophysiologic processes in heart failure and could be useful in diagnostic as well as therapeutic setting. Conclusion: Based on our analysis by a biomarker-driven approach in heart failure therapy, patients could be treated more specifically in long term with a consideration of different aspects of heart failure. New studies evaluating a multimarker - based therapeutic approach could lead in a decrease in the morbidity and mortality of heart failure patients.

Pulmonary Hypertension Due to Left Heart Disease-A Practical Approach to Diagnosis and Management

Pulmonary hypertension (PH) due to left heart disease (LHD) is a frequent complication of heart failure (HF) and is associated with exercise intolerance, poor quality of life, increased risk of hospitalisations, and reduced overall survival. Since the recent Sixth World Symposium on Pulmonary Hypertension in 2018, there have been significant changes in the hemodynamic definitions and clinical classification of PH-LHD. PH-LHD can be subdivided into (1) isolated postcapillary PH (IpcPH) and (2) combined precapillary and postcapillary PH (CpcPH). This categorisation of PH-LHD is important because CpcPH shares certain pathophysiologic, clinical, and hemodynamic characteristics with pulmonary arterial hypertension and is associated with worse outcomes compared with IpcPH. A systematic approach using clinical history and noninvasive investigations is required in the diagnosis of PH-LHD. Right heart catheterisation with and without provocative testing is performed in expert centres and is indicated in selected individuals. Although the definition of IpcPH and CpcPH is based on measurements made with right heart catheterisation, distinguishing between these two entities is not always necessary. Despite strong evidence for medical therapy in patients with pulmonary arterial hypertension, those options have limited benefit in PH-LHD. Expert PH centres in Canada have been established to provide ongoing care for the more complex patient subgroups.

Targeted therapy with phosphodiesterase 5 inhibitors in patients with pulmonary hypertension due to heart failure and elevated pulmonary vascular resistance: a systematic review

Pulmonary Hypertension due to left heart disease is the most common type of Pulmonary Hypertension. Morbidity and mortality significantly increase once Pulmonary Hypertension is present. Treatment is aimed toward optimizing the underlying condition. Targeted therapy has been evaluated in small studies with mixed results. The goal of this systematic review is to identify the possible benefit and safety of Phosphodiesterase 5 inhibitors in Pulmonary Hypertension due to left heart disease with elevated pulmonary vascular resistance, diagnosed by right heart catheterization. Electronic searches using MEDLINE/PREMEDLINE, EMBASE, and The Cochrane Library were searched on 21 October 2018. Randomized clinical trials comparing Phosphodiesterase 5 inhibitors versus placebo in patients with proven Pulmonary Hypertension by right heart catheterization secondary to left heart disease (both heart failure with reduced ejection fraction and with preserved ejection fraction) and reported pulmonary vascular resistance were included. We identified 436 potentially relevant studies. After reviewing the titles and abstracts to exclude irrelevant articles, five randomized clinical trials were considered for the study. Sildenafil was well tolerated among all studies. Sildenafil was found to improve hemodynamics, exercise capacity, and quality of life in patients with elevated pulmonary vascular resistance. Phosphodiesterase 5 inhibitors therapy in patients with proven Pulmonary Hypertension due to left heart disease and elevated pulmonary vascular resistance by right heart catheterization may improve the quality of life, exercise capacity, and pulmonary hemodynamics. Further prospective randomized controlled studies are needed to confirm.

Current Understanding of Circulating Biomarkers in Pulmonary Hypertension Due to Left Heart Disease

Pulmonary hypertension due to left heart disease (PH-LHD; Group 2), especially in the setting of heart failure with preserved ejection fraction (HFpEF), is the most frequent cause of PH. Despite its prevalence, no effective therapies for PH-LHD are available at present. This is largely due to the lack of a concise definition for hemodynamic phenotyping, existence of significant gaps in the understanding of the underlying pathology and the impact of associated comorbidities, as well as the absence of specific biomarkers that can aid in the early diagnosis and management of this challenging syndrome. Currently, B-type natriuretic peptide (BNP) and N-terminal proBNP (NT-proBNP) are guideline-recommended biomarkers for the diagnosis and prognosis of heart failure (HF) and PH. Endothelin-1 (ET-1), vascular endothelial growth factor-D (VEGF-D), and microRNA-206 have also been recently identified as new potential circulating biomarkers for patients with PH-LHD. In this review, we aim to present the current state of knowledge of circulating biomarkers that can be used to guide future research toward diagnosis, refine specific patient phenotype, and develop therapeutic approaches for PH-LHD, with a particular focus on PH-HFpEF. Potential circulating biomarkers identified in pre-clinical models of PH-LHD are also summarized here.

Emerging therapies for right ventricular dysfunction and failure

Therapeutic options for right ventricular (RV) dysfunction and failure are strongly limited. Right heart failure (RHF) has been mostly addressed in the context of pulmonary arterial hypertension (PAH), where it is not possible to discern pulmonary vascular- and RV-directed effects of therapeutic approaches. In part, opposing pathomechanisms in RV and pulmonary vasculature, i.e., regarding apoptosis, angiogenesis and proliferation, complicate addressing RHF in PAH. Therapy effective for left heart failure is not applicable to RHF, e.g., inhibition of adrenoceptor signaling and of the renin-angiotensin system had no or only limited success. A number of experimental studies employing animal models for PAH or RV dysfunction or failure have identified beneficial effects of novel pharmacological agents, with most promising results obtained with modulators of metabolism and reactive oxygen species or inflammation, respectively. In addition, established PAH agents, in particular phosphodiesterase-5 inhibitors and soluble guanylate cyclase stimulators, may directly address RV integrity. Promising results are furthermore derived with microRNA (miRNA) and long non-coding RNA (lncRNA) blocking or mimetic strategies, which can target microvascular rarefaction, inflammation, metabolism or fibrotic and hypertrophic remodeling in the dysfunctional RV. Likewise, pre-clinical data demonstrate that cell-based therapies using stem or progenitor cells have beneficial effects on the RV, mainly by improving the microvascular system, however clinical success will largely depend on delivery routes. A particular option for PAH is targeted denervation of the pulmonary vasculature, given the sympathetic overdrive in PAH patients. Finally, acute and durable mechanical circulatory support are available for the right heart, which however has been tested mostly in RHF with concomitant left heart disease. Here, we aim to review current pharmacological, RNA- and cell-based therapeutic options and their potential to directly target the RV and to review available data for pulmonary artery denervation and mechanical circulatory support.

Pulmonary hypertension due to left heart disease with pulmonary arterial wedge pressure ≤15 mm Hg

BACKGROUND

Pulmonary hypertension due to left heart disease (PH-LHD) is the most prevalent type of pulmonary hypertension (PH). The hemodynamic diagnostic standard of pulmonary arterial wedge pressure (PAWP) >15 mm Hg that is traditionally recommended by guidelines is being challenged.

METHODS

To address this problem, we analyzed the data of 154 patients with PH-LHD admitted to our center from April 2013 to March 2018. Pharmacological or nonpharmacological treatment of underlying left heart disease was offered to all 154 patients.

RESULTS

In total, there were 24 patients (15.6%) with PAWP ≤15 mm Hg. Comparison of echocardiography and right heart catheterization parameters between the two groups (PAWP >15 mm Hg and PAWP ≤15 mm Hg) showed that the group with PAWP ≤15 mm Hg had smaller left ventricular diameter, higher cardiac output, lower pressure and higher oxygen saturation in the pulmonary artery, right atrium, right ventricle, and superior vena cava. No significant difference was found regarding dilated cardiomyopathy, diabetes mellitus, hypertension, atrial fibrillation, and left heart valvular disease, but a significant difference was found for coronary heart disease (higher morbidity in group with PAWP ≤15 mm Hg) between the two groups.

CONCLUSION

We found that 15.6% of the patients with PH-LHD under pharmacological or nonpharmacological treatment had PAWP ≤15 mm Hg. These results suggest that the diagnostic criterion of PAWP and the characteristics for this group of patients should be further investigated.

Sympathetic nervous system activation and heart failure: Current state of evidence and the pathophysiology in the light of novel biomarkers

Heart failure (HF) is a complex clinical syndrome characterized by the activation of at least several neurohumoral pathways that have a common role in maintaining cardiac output and adequate perfusion pressure of target organs and tissues. The sympathetic nervous system (SNS) is upregulated in HF as evident in dysfunctional baroreceptor and chemoreceptor reflexes, circulating and neuronal catecholamine spillover, attenuated parasympathetic response, and augmented sympathetic outflow to the heart, kidneys and skeletal muscles. When these sympathoexcitatory effects on the cardiovascular system are sustained chronically they initiate the vicious circle of HF progression and become associated with cardiomyocyte apoptosis, maladaptive ventricular and vascular remodeling, arrhythmogenesis, and poor prognosis in patients with HF. These detrimental effects of SNS activity on outcomes in HF warrant adequate diagnostic and treatment modalities. Therefore, this review summarizes basic physiological concepts about the interaction of SNS with the cardiovascular system and highlights key pathophysiological mechanisms of SNS derangement in HF. Finally, special emphasis in this review is placed on the integrative and up-to-date overview of diagnostic modalities such as SNS imaging methods and novel laboratory biomarkers that could aid in the assessment of the degree of SNS activation and provide reliable prognostic information among patients with HF.

Pulmonary Hypertension Due to Left Heart Disease

Pulmonary hypertension (PH) due to left heart disease (LHD) is the most common type of PH and is defined as mean pulmonary artery systolic pressure of >20 mm Hg and pulmonary capillary wedge pressure >15 mm Hg during right heart catheterization. LHD may lead to elevated left atrial pressure alone, which in the absence of intrinsic pulmonary vascular disease will result in PH without changes in pulmonary vascular resistance. Persistent elevation in left atrial pressure may, however, also be associated with subsequent pulmonary vascular remodeling, vasoconstriction, and an increase in pulmonary vascular resistance. Hence, there are 2 subgroups of PH due to LHD, isolated postcapillary PH and combined post- and precapillary PH, with these groups have differing clinical implications. Differentiation of pulmonary arterial hypertension and PH due to LHD is critical to guide management planning; however, this may be challenging. Older patients, patients with metabolic syndrome, and patients with imaging and clinical features consistent with left ventricular dysfunction are suggestive of LHD etiology rather than pulmonary arterial hypertension. Hemodynamic measures such as diastolic pressure gradient, transpulmonary gradient, and pulmonary vascular resistance may assist to differentiate pre- from postcapillary PH and offer prognostic insights. However, these are influenced by fluid status and heart failure treatment. Pulmonary arterial hypertension therapies have been trialed in the treatment with concerning results reflecting disease heterogeneity, variation in inclusion criteria, and mixed end point criteria. The aim of this review is to provide an updated definition, discuss possible pathophysiology, clinical aspects, and the available treatment options for PH due to LHD.

Treatment With Treprostinil and Metformin Normalizes Hyperglycemia and Improves Cardiac Function in Pulmonary Hypertension Associated With Heart Failure With Preserved Ejection Fraction

OBJECTIVE

Pulmonary hypertension (PH) due to left heart disease (group 2), especially in the setting of heart failure with preserved ejection fraction (HFpEF), is the most common cause of PH worldwide; however, at present, there is no proven effective therapy available for its treatment. PH-HFpEF is associated with insulin resistance and features of metabolic syndrome. The stable prostacyclin analog, treprostinil, is an effective and widely used Food and Drug Administration-approved drug for the treatment of pulmonary arterial hypertension. While the effect of treprostinil on metabolic syndrome is unknown, a recent study suggests that the prostacyclin analog beraprost can improve glucose intolerance and insulin sensitivity. We sought to evaluate the effectiveness of treprostinil in the treatment of metabolic syndrome-associated PH-HFpEF. Approach and Results: Treprostinil treatment was given to mice with mild metabolic syndrome-associated PH-HFpEF induced by high-fat diet and to SU5416/obese ZSF1 rats, a model created by the treatment of rats with a more profound metabolic syndrome due to double leptin receptor defect (obese ZSF1) with a vascular endothelial growth factor receptor blocker SU5416. In high-fat diet-exposed mice, chronic treatment with treprostinil reduced hyperglycemia and pulmonary hypertension. In SU5416/Obese ZSF1 rats, treprostinil improved hyperglycemia with similar efficacy to that of metformin (a first-line drug for type 2 diabetes mellitus); the glucose-lowering effect of treprostinil was further potentiated by the combined treatment with metformin. Early treatment with treprostinil in SU5416/Obese ZSF1 rats lowered pulmonary pressures, and a late treatment with treprostinil together with metformin improved pulmonary artery acceleration time to ejection time ratio and tricuspid annular plane systolic excursion with AMPK (AMP-activated protein kinase) activation in skeletal muscle and the right ventricle.

CONCLUSIONS

Our data suggest a potential use of treprostinil as an early treatment for mild metabolic syndrome-associated PH-HFpEF and that combined treatment with treprostinil and metformin may improve hyperglycemia and cardiac function in a more severe disease.

Pulmonary Hypertension in Heart Failure Patients

The development of pulmonary hypertension (PH) in patients with heart failure is associated with increased morbidity and mortality. In this article, the authors examine recent changes to the definition of PH in the setting of left heart disease (PH-LHD), and discuss its epidemiology, pathophysiology and prognosis. They also explore the complexities of diagnosing PH-LHD and the current evidence for the use of medical therapies, promising clinical trials and the role of left ventricular assist device and transplantation.

Endothelin: 30 Years From Discovery to Therapy

Discovered in 1987 as a potent endothelial cell-derived vasoconstrictor peptide, endothelin-1 (ET-1), the predominant member of the endothelin peptide family, is now recognized as a multifunctional peptide with cytokine-like activity contributing to almost all aspects of physiology and cell function. More than 30 000 scientific articles on endothelin were published over the past 3 decades, leading to the development and subsequent regulatory approval of a new class of therapeutics-the endothelin receptor antagonists (ERAs). This article reviews the history of the discovery of endothelin and its role in genetics, physiology, and disease. Here, we summarize the main clinical trials using ERAs and discuss the role of endothelin in cardiovascular diseases such as arterial hypertension, preecclampsia, coronary atherosclerosis, myocardial infarction in the absence of obstructive coronary artery disease (MINOCA) caused by spontaneous coronary artery dissection (SCAD), Takotsubo syndrome, and heart failure. We also discuss how endothelins contributes to diabetic kidney disease and focal segmental glomerulosclerosis, pulmonary arterial hypertension, as well as cancer, immune disorders, and allograft rejection (which all involve ET_A autoantibodies), and neurological diseases. The application of ERAs, dual endothelin receptor/angiotensin receptor antagonists (DARAs), selective ET_B agonists, novel biologics such as receptor-targeting antibodies, or immunization against ET_A receptors holds the potential to slow the progression or even reverse chronic noncommunicable diseases. Future clinical studies will show whether targeting endothelin receptors can prevent or reduce disability from disease and improve clinical outcome, quality of life, and survival in patients.

Challenges in pulmonary hypertension associated with left heart disease

Introduction: Pulmonary hypertension (PH) secondary to left-sided heart disease (Group 2 PH) is a frequent complication of heart failure (HF) and is a heterogeneous phenotypic disorder that worsens exercise capacity, increases risk for hospitalization and survival independent of left ventricular ejection fraction (LVEF) or stage of HF. Areas covered: In this review, an update of the current knowledge and some potential challenges about the pathophysiology and treatments of group 2 PH in patients with HF of either preserved or reduced ejection fraction are provided. Also, this review discusses the epidemiology and provides hints for the optimal evaluation and diagnosis of these patients to prevent misclassification of their pulmonary hypertension. Expert opinion: There are many of areas lacking knowledge and understanding in the field of pulmonary hypertension associated to left heart disease (PH-LHD) that should be addressed in the future. Further research should be performed, in terms of pathobiology, and understanding the predisposition (genetic susceptibility and contributing factors) of the different phenotypes of this disorder. More clinical trials targeting new therapeutic options and specific PH therapies are warranted to help this increasing important patient group as the current guidelines recommend to only treat the underlying left-sided heart disease.

Pulmonary vascular disease in the setting of heart failure with preserved ejection fraction

Heart failure with preserved ejection fraction (HFpEF) is defined as clinical features of heart failure, ideally with biomarker evidence such as elevated plasma natriuretic peptide levels, in the setting of an ejection fraction (EF) greater than 50% and imaging evidence of diastolic left ventricular dysfunction [1,2]. In the absence of cardiac imaging or invasive hemodynamics, this is a clinical syndrome that is often indistinguishable from heart failure with reduced ejection fraction (HFrEF). HFpEF and HFrEF present with a cadre of comparable signs and symptoms including jugular venous distention, pulmonary rales on auscultation, breathlessness, orthopnea, exercise intolerance, exertional dyspnea, fatigue and peripheral edema. HFpEF accounts for at least half of all diagnoses of heart failure [1,2]. Pulmonary hypertension (PH) is a common complication of HFpEF that is linked to worse disease morbidity and mortality. In fact, mortality has been linked to increases in the intrinsic pulmonary vascular resistance in the setting of increased left ventricular end diastolic pressure, characterized hemodynamically by rises in the transpulmonary pressure gradient, pulmonary vascular resistance or diastolic pressure gradient. Despite being the most common form of PH, there are no approved therapies for the treatment of PH secondary to HFpEF. This review will summarize the hemodynamic classifications of PH in the setting of HFpEF, mechanisms of disease, the potential contribution of pulmonary vascular disease to poor outcomes in patients with HFpEF, and new approaches to therapy.

Endothelial cell-cardiomyocyte crosstalk in heart development and disease

The crosstalk between endothelial cells and cardiomyocytes has emerged as a requisite for normal cardiac development, but also a key pathogenic player during the onset and progression of cardiac disease. Endothelial cells and cardiomyocytes are in close proximity and communicate through the secretion of paracrine signals, as well as through direct cell-to-cell contact. Here, we provide an overview of the endothelial cell-cardiomyocyte interactions controlling heart development and the main processes affecting the heart in normal and pathological conditions, including ischaemia, remodelling and metabolic dysfunction. We also discuss the possible role of these interactions in cardiac regeneration and encourage the further improvement of in vitro models able to reproduce the complex environment of the cardiac tissue, in order to better define the mechanisms by which endothelial cells and cardiomyocytes interact with a final aim of developing novel therapeutic opportunities.