Outcomes in World Health Organization Group II Pulmonary Hypertension: Mortality and Readmission Trends With Systolic and Preserved Ejection Fraction–Induced Pulmonary Hypertension

Pulmonary hypertension associated to left heart disease: Phenotypes and treatment

Pulmonary hypertension associated to left heart disease (PH-LHD) refers to a clinical and haemodynamic condition of pulmonary hypertension associated with a heterogeneous group of diseases affecting any of the compartments that form the left ventricle and left atrium. PH-LHD is the most common cause of PH, accounting for 65-80 % of diagnoses. Based on the haemodynamic phase of the disease, PH-LDH is classified into three subgroups: postcapillary PH, isolated postcapillary PH and combined pre-postcapillary PH (CpcPH). Several signaling pathways involved in the regulation of vascular tone are dysfunctional in PH-LHD, including nitric oxide, MAP kinase and endothelin-1 pathways. These pathways are the same as those altered in PH group 1, however PH-LHD can heardly be treated by specific drugs that act on the pulmonary circulation. In this manuscript we provide a state of the art of the available clinical trials investigating the safety and efficacy of PAH-specific drugs, as well as drugs active in patients with heart failure and PH-LHD. We also discuss the different phenotypes of PH-LHD, as well as molecular targets and signaling pathways potentially involved in the pathophysiology of the disease. Finally we will mention some new emerging therapies that can be used to treat this form of PH.

Novel insights into the pathobiology of pulmonary hypertension in heart failure with preserved ejection fraction

Heart failure (HF) with preserved ejection fraction (HFpEF) is the most common cause of pulmonary hypertension (PH) worldwide and is strongly associated with adverse clinical outcomes. The American Heart Association recently highlighted a call to action regarding the distinct lack of evidence-based treatments for PH due to poorly understood pathophysiology of PH attributable to HFpEF (PH-HFpEF). Prior studies have described cardiophysiological mechanisms to explain the development of isolated postcapillary PH (ipc-PH); however, the consequent increase in pulmonary vascular (PV) resistance (PVR) may lead to the less understood and more fatal combined pre- and postcapillary PH (cpc-PH). Metabolic disease and inflammatory dysregulation have been suggested to predispose PH, yet the molecular mechanisms are unknown. Although PH-HFpEF has been studied to partly share vasoactive neurohormonal mediators with primary pulmonary arterial hypertension (PAH), clinical trials that have targeted these pathways have been unsuccessful. The increased mortality of patients with PH-HFpEF necessitates further study into viable mechanistic targets involved in disease progression. We aim to summarize the current pathophysiological and clinical understanding of PH-HFpEF, highlight the role of known molecular mechanisms in the progression of PV disease, and introduce a novel concept that lipid metabolism may be attenuating and propagating PH-HFpEF.NEW & NOTEWORTHY Our review addresses pulmonary hypertension (PH) attributable to heart failure (HF) with preserved ejection fraction (HFpEF; PH-HFpEF). Current knowledge gaps in PH-HFpEF pathophysiology have led to a lack of therapeutic targets. Thus, we address identified knowledge gaps in a comprehensive review, focusing on current clinical epidemiology, known pathophysiology, and previously studied molecular mechanisms. We also introduce a comprehensive review of polyunsaturated fatty acid (PUFA) lipid inflammatory mediators in PH-HFpEF.

The Impact of Diabetes on Haemodynamic and Cardiometabolic Responses in Heart Failure With Preserved Ejection Fraction

AIMS

Heart failure with preserved ejection (HFpEF) and diabetes mellitus (DM) commonly co-exist. However, it is unclear if DM modifies the haemodynamic and cardiometabolic phenotype in patients with HFpEF. We aimed to interrogate the haemodynamic and cardiometabolic effects of DM in HFpEF.

METHODS

We compared the haemodynamic and metabolic profiles of non-DM patients and patients with DM-HFpEF at rest and during exercise using right heart catheterisation and mixed venous blood gas analysis.

RESULTS

Of 181 patients with HFpEF, 37 (20%) had DM. Patients with DM displayed a more adverse exercise haemodynamic response vs HFpEF alone (mean pulmonary arterial pressure: 47 mmHg [interquartile range {IQR} 42-55] vs 42 [38-47], p<0.001; workload indexed pulmonary capillary wedge pressure indexed: 0.80 mmHg/W [0.44-1.23] vs 0.57 [0.43-1.01], p=0.047). HFpEF-DM patients had a lower mixed venous oxygen saturation at rest (70% [IQR 66-73] vs 72 [69-75], p=0.003) and were unable to enhance O2 extraction to the same extent (Δ-28% [-33 to -15] vs -29 [-36 to -21], p=0.029), this occurred at a 22% lower median workload. Resting mixed venous lactate levels were higher in those with DM (1.5 mmol/L [IQR 1.1-1.9] vs 1 [0.9-1.3], p<0.001), and during exercise indexed to workload (0.09 mmol/L/W [0.06-0.13] vs 0.08 [0.05-0.11], p=0.018).

CONCLUSION

Concurrent diabetes and HFpEF was associated with greater metabolic responses at rest, with enhanced wedge driven pulmonary hypertension and relative lactataemia during exercise without appropriate augmentation of oxygen consumption.

The future of group 2 pulmonary hypertension: Exploring clinical trials and therapeutic targets

Pulmonary hypertension due to left heart disease (PH-LHD) or group 2 PH is the most common and lethal form of PH, occurring secondary to left ventricular systolic or diastolic heart failure (HF), left-sided valvular diseases, and congenital abnormalities. It is subdivided into isolated postcapillary PH (IpcPH) and combined pre- and post-capillary PH (CpcPH), with the latter sharing many similarities with group 1 PH. CpcPH is associated with worse outcomes and increased morbidity and mortality when compared to IpcPH. Although IpcPH can be improved by treatment of the underlying LHD, CpcPH is an incurable disease for which no specific treatment exists, likely due to the lack of understanding of its underlying mechanisms. Furthermore, drugs approved for PAH are not recommended for group 2 PH, as they are either ineffective or even deleterious. With this major unmet medical need, a better understanding of mechanisms and the identification of effective treatment strategies for this deadly condition are urgently needed. This review presents relevant background of the molecular mechanisms underlying PH-LHD that could translate into innovative therapeutic targets and explores novel targets currently being evaluated in clinical trials.

The emerging role of sacubitril/valsartan in pulmonary hypertension with heart failure

Pulmonary hypertension due to left heart disease (PH-LHD) represents approximately 65%-80% of all patients with PH. The progression, prognosis, and mortality of individuals with left heart failure (LHF) are significantly influenced by PH and right ventricular (RV) dysfunction. Consequently, cardiologists should devote ample attention to the interplay between HF and PH. Patients with PH and HF may not receive optimal benefits from the therapeutic effects of prostaglandins, endothelin receptor antagonists, or phosphodiesterase inhibitors, which are specific drugs for pulmonary arterial hypertension (PAH). Sacubitril/valsartan, the angiotensin receptor II blocker-neprilysin inhibitor (ARNI), was recommended as the first-line therapy for patients with heart failure with reduced ejection fraction (HFrEF) by the 2021 European Society of Cardiology Guidelines. Although ARNI is effective in treating left ventricular (LV) enlargement and lower ejection fraction, its efficacy in treating individuals with PH and HF remains underexplored. Considering its vasodilatory effect at the pre-capillary level and a natriuretic drainage role at the post-capillary level, ARNI is believed to have a broad range of potential applications in treating PH-LHD. This review discusses the fundamental pathophysiological connections between PH and HF, emphasizing the latest research and potential benefits of ARNI in PH with various types of LHF and RV dysfunction.

The prevalence and survival of pulmonary hypertension due to left heart failure: A retrospective analysis of a multicenter prospective cohort study

Background

Pulmonary hypertension due to left heart failure (PH-LHF) is currently the most common form of pulmonary hypertension (PH) encountered in clinical practice. Despite significant advances that have improved our understanding of PH-LHF over the past two decades, the mortality is still high in recent decades. This study aimed to describe the prevalence and survival of patients with PH-LHF, and explored the potential risk factors which may predict the prognosis of PH-LHF.

Methods

A retrospective analysis of a prospective cohort study of left heart failure (LHF) patients who underwent right heart catheterization (RHC) between January 2013 and November 2016 was performed. The endpoint was all-cause mortality. Follow-ups were performed every 6 months ± 2 weeks.

Results

A total of 480 patients with LHF were enrolled, with 215 (44.8%) having PH-LHF. The proportion of PH-LHF was significantly lower in coronary artery disease (CAD) group than without CAD (41.3 vs. 57.8%, p = 0.003). However, multivariable logistic regression analysis revealed that CAD was not associated with PH-LHF (Adjusted OR: 1.055, 95% CI: 0.576 – 1.935, p = 0.862). 75 of 215 (34.9%) patients with PH-LHF died during a median follow-up period of 84.6 months. The 1-, 3-, 5-, and 8-year survival rates of all PH-LHF patients were 94.3, 76.9, 65.8, and 60.2%, respectively. New York Heart Association Functional Class (NYHA FC), hemoglobin, and systolic pulmonary artery pressure (sPAP) were associated with mortality of PH-LHF in multivariate Cox analysis.

Conclusion

PH is commonly identified in patients with LHF, with a prevalence of approximately 45%. The mortality is still high in patients with PH-LHF. NYHA FC, hemoglobin, and sPAP are independent risk predictors of mortality for PH-LHF. These findings may be useful for risk stratification in future clinical trial enrollment.

Emerging therapies: The potential roles SGLT2 inhibitors, GLP1 agonists, and ARNI therapy for ARNI pulmonary hypertension

Pulmonary hypertension (PH) is a highly morbid condition. PH due to left heart disease (PH-LHD) has no specific therapies and pulmonary arterial hypertension (PAH) has substantial residual risk despite several approved therapies. Multiple lines of experimental evidence link metabolic dysfunction to the pathogenesis and outcomes in PH-LHD and PAH, and novel metabolic agents hold promise to improve outcomes in these populations. The antidiabetic sodium-glucose cotransporter 2 (SGLT2) inhibitors and glucagon-like peptide-1 (GLP1) agonists targeting metabolic dysfunction and improve outcomes in patients with LHD but have not been tested specifically in patients with PH. The angiotensin receptor/neprilysin inhibitors (ARNIs) produce significant improvements in cardiac hemodynamics and may improve metabolic dysfunction that could benefit the pulmonary circulation and right ventricle function. On the basis of promising preclinical work with these medications and clinical rationale, we explore the potential of SGLT2 inhibitors, GLP1 agonists, and ARNIs as therapies for both PH-LHD and PAH.

Reduction of Pulmonary Hypertension After Transition to Sacubitril/Valsartan in Patients With Heart Failure With Preserved Ejection Fraction

Objectives: Although the PARAGON-HF trial failed to reach its primary endpoint, subgroups of patients with heart failure with preserved ejection fraction (HFpEF) still appear to benefit from Sacubitril/Valsartan therapy. As HFpEF patients with pulmonary hypertension display a specifically high mortality and morbidity, we evaluated the effect of Sacubitril/Valsartan in this subgroup of HFpEF patients.

Methods: In this retrospective case-series of 18 patients with HFpEF and pulmonary hypertension, right heart catheterisation (RHC) for determination of invasive pulmonary pressure were performed at baseline (pre-Sacubitril/Valsartan) and 99 (71–156) days after transition from angiotensin-converting enzyme inhibitors and angiotensin receptor blockers to Sacubitril/Valsartan (post-Sacubitril/Valsartan). Results are given as median and interquartile range.

Results: After conversion to Sacubitril/Valsartan, RHC showed significantly reduced pulmonary artery pressure (PAP) and mean pulmonary capillary wedge pressure (PCWP) compared to pre-Sacubitril/Valsartan [PAP systolic/diastolic/mean 44 (38–55)/15 (11–20)/27 (23–33) mm Hg vs. 51 (41–82)/22 (13–29)/33 (28–52) mm Hg, p < 0.05 and p < 0.01, respectively; PCWP 16 (12–20) mm Hg vs. 22 (15–27) mm Hg, p < 0.05]. Median Sacubitril/Valsartan dosage was 24/26 mg BID (24/26 BID−49/51 mg BID). Clinically, New York Heart Association functional class improved in 12 of the 18 patients (p < 0.01) after conversion to Sacubitril/Valsartan. Echocardiographic parameters of left ventricular function and cardiovascular co-medication did not differ markedly between pre- and post-Sacubitril/Valsartan.

Conclusion: Sacubitril/Valsartan therapy is associated with an improvement of pulmonary hypertension in HFpEF patients.

Phosphodiesterase-5 Inhibitors and Outcomes During Left Ventricular Assist Device Support: A Systematic Review and Meta-Analysis

BACKGROUND

Phosphodiesterase-5 inhibitors (PDE5i) have been used to treat pulmonary hypertension and right ventricular failure in patients with left ventricular assist devices (LVAD). The effects of PDE5i on post-LVAD outcomes including hemocompatibility-related adverse events are not well-established. This systematic review and meta-analysis aims to evaluate the effects of PDE5i on post-LVAD outcomes.

METHODS AND RESULTS

A comprehensive literature search was conducted using Pubmed and Embase databases from inception through November 25, 2020, to compare post-LVAD outcomes in patients with or without PDE5i use. Pooled odds ratio (OR) with 95% confidence intervals (CI) and I² statistic were calculated. Thirteen observational studies were included in this analysis. The use of PDE5i was not significantly associated with lower postoperative right ventricular failure (OR 0.38, 95% CI 0.02-5.96, P = .41). There was no significant association between PDE5i and gastrointestinal bleeding (OR 1.23, 95% CI 0.76-1.98, P = .2), overall stroke (OR 0.60, 95% CI 0.21-1.68, P = .17), ischemic stroke (OR 0.61, 95% CI 0.09-4.07, P = .38), or pump thrombosis (OR 0.71, 95% CI 0.14-3.54, P = .46).

CONCLUSIONS

Our meta-analysis showed no significant association between PDE5i and post-LVAD right ventricular failure. Despite the antiplatelet effects of PDE5i, there was no significant association between PDE5i and gastrointestinal bleeding, overall stroke, ischemic stroke, or pump thrombosis. Randomized controlled studies are warranted to evaluate the net benefits or harms of PDE5i in the LVAD population.

Computed Tomography Angiography-Based Pulmonary Artery Volumetry as a Diagnostic Tool for Pulmonary Hypertension

OBJECTIVES

We evaluated use of three-dimensional pulmonary artery volumes derived from computed tomography pulmonary angiography (CTPA) in a group with pulmonary hypertension (PH) compared with healthy controls as a tool for the diagnosis of PH.

METHODS

Retrospective analysis was performed of 40 CTPA scans obtained within 90 days of right heart catheterization demonstrating PH. The CTPA scans of 40 age- and sex-matched patients without cardiopulmonary disease were used as comparison. Diameters and volumes of the pulmonary arteries were compared.

RESULTS

Adjusted total volume of the main, right, and left proximal pulmonary arteries (PAvol) demonstrated area under the curve of 0.918 (95% confidence interval, 0.860-0.975) for detection of PH, comparable to main pulmonary artery diameter measurement. Area under the curve values for PAvol were higher in subgroups divided by sex and PH severity.

CONCLUSIONS

Volumetric analysis of the proximal pulmonary arteries using CTPA is a promising diagnostic tool for PH in a real-world cohort.

Metformin in Pulmonary Hypertension in Left Heart Disease

Metformin is ubiquitously used in the management of Type II Diabetes Mellitus (DMII). Over the years, our growing knowledge of its therapeutic potential has broadened its use to the treatment of infertility in polycystic ovarian syndrome, gestational diabetes, and even obesity. Recently, it has been suggested as a novel therapy in cardiovascular disease (CVD). Given that CVD is the leading cause of death in patients with DMII, with ~ 75% dying from a cardiovascular event, the intersection of DMII and CVD provides a unique therapeutic target. In particular, pulmonary hypertension (PH) related to CVD (Group II PH) may be an optimal target for metformin therapy. The objective of this review article is to provide an overview of the pathophysiology of PH related to left heart disease (PH-LHD), outline the proposed pathophysiologic mechanism of insulin resistance in heart failure and PH-LHD, and evaluate the role metformin may have in heart failure and PH-LHD.

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.

Transcriptome-wide analysis associates ID2 expression with combined pre- and post-capillary pulmonary hypertension

Heart failure with preserved ejection fraction (HFpEF) patients who develop pulmonary hypertension (PH) have an increased risk of death, with combined pre- and post-capillary PH (CpcPH) having the highest risk. However, the mechanism behind PH development in HFpEF is poorly understood. We aimed to identify transcriptomic associations with PH development in HFpEF. Blood was collected from 30 HFpEF patients: 10 without PH, 10 with isolated post-capillary PH, and 10 with CpcPH. Gene expression measurements were completed using transcriptome-wide RNA sequencing. Gene expression differences were compared using a quasi-likelihood method adjusting for age, sex, race, and smoking-status. Biological pathways were compared using global gene expression differences. A replication in 34 additional heart failure patients and a validation in lung tissue from a representative mouse model were completed using quantitative PCR. Six differentially expressed genes were identified when comparing transcriptomics between subjects with CpcPH and those without PH. When tested in additional subjects, only the association with ID2 replicated. Consistent with clinical findings, Id2 expression was also upregulated in mice with HFpEF and PH. Pathway analysis identified proliferative and mitochondrial pathways associated with CpcPH. Thus, these patients may possess systemic pathophysiological differences similar to those observed in pulmonary arterial hypertension patients.

Association Between Hemodynamic Markers of Pulmonary Hypertension and Outcomes in Heart Failure With Preserved Ejection Fraction

Importance

Heart failure with preserved ejection fraction (HFpEF) is highly prevalent, yet there are no specific therapies, possibly due to phenotypic heterogeneity. The development of pulmonary hypertension (PH) in patients with HFpEF is considered a high-risk phenotype in need of targeted therapies, but there have been limited hemodynamic and outcomes data.

Objective

To identify the hemodynamic characteristics and outcomes of PH-HFpEF.

Design, Setting, and Participants

Cohort study of participants who had a right heart catheterization from January 2005 to September 2012 (median [interquartile range] follow-up time, 1578 [554-2513] days) were analyzed. Hemodynamic catheterization data was linked to the clinical data repository of all inpatient and outpatient encounters across a health system. Single tertiary referral center for heart failure and PH within a large health care network using a common clinical data repository was studied. There were 19 262 procedures in 10 023 participants.

Exposures

Participants were classified as having no PH, precapillary PH, or PH in the setting of left heart disease (reduced or preserved ejection fraction). Pulmonary hypertension associated with HFpEF was defined as mean pulmonary artery pressure of 25 mm Hg or more, pulmonary artery wedge pressure of 15 mm Hg or more, and left ventricular ejection fraction of 45% or more. Pulmonary hypertension severity was quantified by the hemodynamic parameters transpulmonary gradient, pulmonary vascular resistance, and diastolic pulmonary gradient.

Main Outcomes and Measures

The primary outcome was time to all-cause mortality. Secondary outcomes were time to acute hospitalization and cardiovascular hospitalization.

Results

The mean (SD) of all study individuals was 65 (38) years. Of 10 023 individuals, 2587 (25.8%) had PH-HFpEF. Mortality was 23.6% at 1 year and 48.2% at 5 years. Cardiac hospitalizations occurred in 28.1% at 1 year and 47.4% at 5 years. The frequency of precapillary PH using clinically defined cut-offs for transpulmonary gradient (>12 mm Hg), pulmonary vascular resistance (3 Woods units), and diastolic pulmonary gradient (≥7 mm Hg) were 12.6%, 8.8%, and 3.5%, respectively. Transpulmonary gradient, pulmonary vascular resistance, and diastolic pressure gradient were predictive of mortality and cardiac hospitalizations.

Conclusions and Relevance

In a large cohort referred for invasive hemodynamic assessment, PH-HFpEF was common. Transpulmonary gradient, pulmonary vascular resistance, and diastolic pulmonary gradient are all associated with mortality and cardiac hospitalizations.

Relationship between pulmonary hypertension and outcomes among patients with heart failure with reduced ejection fraction

Objectives: To identify predictors of pulmonary hypertension (PHT) and the predictive value of PHT for rehospitalization among patients with heart failure with reduced ejection fraction (HFrEF). Methods: A retrospective study of 351 hospitalized patients with heart failure (HF). Patients 18 years and above with HFrEF secondary to non-ischemic cardiomyopathy were reviewed. Patients with coronary artery disease, preserved ejection fraction and other secondary causes of PHT apart from HF were excluded. PHT as a predictor of 30-day and six-month re-admission was assessed as well as important possible predictors of PHT. Cox regression analysis, multiple linear regression as well as other statistical tools were employed as deemed appropriate. Results: Thirty-seven (37) and 99 patients were re-hospitalized within 30 days and 6 months after discharge for decompensated HF, respectively. After Cox regression analysis, higher hemoglobin reduced the odds of rehospitalization for decompensated HF (p = 0.015) within 30 days after discharge while higher pulmonary artery systolic pressure (PASP) (p = 0.002) and blood urea nitrogen (BUN) (p = 0.041) increased the odds of rehospitalization within 6 months of discharge. The predictors of the PHT among patients with HFrEF after multiple linear regression were low BMI (p = 0.027), increasing age (p = 0.006) and increased left atrial diameter (LAD) on echocardiography (p = 0.0001). Conclusion: Patients with HFrEF have a high predisposition to developing PHT if at admission, they have low BMI, dilated left atrium or are older. Patients with one or more of these attributes may need more intensive therapy to reduce the risk of developing PHT and in turn reduce readmission rates.

Effect of beraprost on pulmonary hypertension due to left ventricular systolic dysfunction

Beraprost is used to treat peripheral chronic arterial occlusive disease. However, the efficacy and safety of beraprost in patients with pulmonary hypertension (PH) due to left ventricular systolic dysfunction (PH-HFrEF) remains unknown. The primary objective of this study was to determine the effects of beraprost on PH-HFrEF.We prospectively recruited patients with PH-HFrEF as determined by echocardiography and right cardiac catheterization. Beraprost sodium was given orally (1 μg/kg/d) added to the usual treatment, and patients were evaluated at 1-year follow-up.Twenty-five patients were recruited with baseline systolic pulmonary artery pressure (PAP) of 49.5 ± 10.8 mm Hg. Systolic PAP results at 3, 6, 9, and 12 months were 39.1 ± 8.1, 30.4 ± 5.2, 27.7 ± 3.0, and 27.0 ± 4.7 mm Hg, respectively, which were all significantly lower than systolic PAP at baseline (P < .05). Left ventricular ejection fraction results at 6 months (43.5 ± 7.0%), 9 months (47.0 ± 5.5%), and 12 months (48.2 ± 4.8%) were significantly higher than at baseline (34.7 ± 9.2%) (P < .05). Six-minute walking distance at 3 months (282.8 ± 80.6 m), 6 months (367.1 ± 81.2 m), 9 months (389.8 ± 87.1 m), and 12 months (395.7 ± 83.4 m) increased with time, and all were significantly higher than baseline (190.1 ± 75.5 m) (P < .05). One patient developed atrial fibrillation and recovered to sinus rhythm after intravenous administration of amiodarone. There were no instances of cardiac-related death, severe bleeding, or severe impairment of liver function.Routine oral administration of beraprost sodium added to the usual treatment may improve cardiopulmonary hemodynamics and exercise capacityin patients with PH-HFrEF.

Insights into the pulmonary vascular complications of heart failure with preserved ejection fraction

Pulmonary hypertension in the setting of heart failure with preserved ejection fraction (PH-HFpEF) is a growing public health problem that is increasing in prevalence. While PH-HFpEF is defined by a high mean pulmonary artery pressure, high left ventricular end-diastolic pressure and a normal ejection fraction, some HFpEF patients develop PH in the presence of pulmonary vascular remodelling with a high transpulmonary pressure gradient or pulmonary vascular resistance. Ageing, increased left atrial pressure and stiffness, mitral regurgitation, as well as features of metabolic syndrome, which include obesity, diabetes and hypertension, are recognized as risk factors for PH-HFpEF. Qualitative studies have documented that patients with PH-HFpEF develop more severe symptoms than those with HFpEF and are associated with more significant exercise intolerance, frequent hospitalizations, right heart failure and reduced survival. Currently, there are no effective therapies for PH-HFpEF, although a number of candidate drugs are being evaluated, including soluble guanylate cyclase stimulators, phosphodiesterase type 5 inhibitors, sodium nitrite and endothelin receptor antagonists. In this review we attempt to provide an updated overview of recent findings pertaining to the pulmonary vascular complications in HFpEF in terms of clinical definitions, epidemiology and pathophysiology. Mechanisms leading to pulmonary vascular remodelling in HFpEF, a summary of pre-clinical models of HFpEF and PH-HFpEF, and new candidate therapeutic strategies for the treatment of PH-HFpEF are summarized.

Pulmonary Hypertension Due to Left Ventricular Cardiomyopathy: Is it the Result or Cause of Disease Progression?

PURPOSE OF REVIEW

The purpose of this review is to define pulmonary hypertension in the setting of left heart disease (PH-LHD), discuss its epidemiology and pathophysiology, and highlight the cause and effect relationship it has with disease progression in the setting of cardiomyopathy.

RECENT FINDINGS

Both pulmonary hypertension (PH) and heart failure are becoming increasingly common. As such, PH-LHD is now the most common form of PH. The pathophysiology of the condition relates to backward transmission of elevated left ventricular filling pressures into the pulmonary circulation and, ultimately, right ventricular (RV) strain/dysfunction. It is evident that these pathophysiologic processes are both the effect and cause of left heart disease progression. In this review, we describe the complex relationship between disease progression in left ventricular cardiomyopathy and PH-LHD. Clinicians and researchers should take note of the importance of PH-LHD and RV dysfunction to appropriately risk stratify patients and develop therapies for the condition.

Management of pulmonary hypertension from left heart disease in candidates for orthotopic heart transplantation

Pulmonary hypertension in left heart disease (PH-LHD) commonly complicates prolonged heart failure (HF). When advanced, the PH becomes fixed or out of proportion and is associated with increased morbidity and mortality in patients undergoing orthotopic heart transplant (OHT). To date, the only recommended treatment of out of proportion PH is the treatment of the underlying HF by reducing the pulmonary capillary wedge pressure (PCWP) with medications and often along with use of mechanical circulatory support. Medical therapies typically used in the treatment of World Health Organization (WHO) group 1 pulmonary arterial hypertension (PAH) have been employed off-label in the setting of PH-LHD with varying efficacy and often negative outcomes. We will discuss the current standard of care including treating HF and use of mechanical circulatory support. In addition, we will review the studies published to date assessing the efficacy and safety of PAH medications in patients with PH-LHD being considered for OHT.

Epidemiology of Pulmonary Hypertension in Left Heart Disease

Pulmonary hypertension (PH) in the setting of left side heart disease is associated with adverse outcomes. The exact prevalence of PH in the different pathologies that affect the left ventricle, however, is difficult to access with the current literature. The lack of a standard definition of PH in older studies, the different modalities to assess pulmonary artery pressures and the varying disease severity, all account for the great variability in the reported prevalence of PH. PH can accompany heart failure (HF) with reduced (HFrEF) or preserved ejection fraction (HFpEF) as well as mitral and aortic valve disease; in any of these instances it is important to recognize whether the elevation of pulmonary pressures is driven by elevated left ventricular pressures only (isolated post-capillary PH) or if there is an accompanying remodeling component in the pulmonary arterioles (combined post-capillary and pre-capillary PH). The objective of this review is to describe the definitions, prevalence and the risk factors associated with the development of PH in the setting of HFrEF, HFpEF and valvular heart disease.

Development of Pulmonary Hypertension in Heart Failure With Preserved Ejection Fraction

Pulmonary hypertension (PH) is common in patients with heart failure with preserved ejection fraction (HFpEF). While PH-HFpEF may affect more than a million patients in the United States alone, it has been difficult to study its epidemiology and response to treatment due to difficulty in properly defining the illness. While chronic remodeling of the pulmonary vasculature is related to chronic passive congestion of the pulmonary circulation from the pulmonary veins, there are likely other contributors to the development of PH-HFpEF. We explore the potential direct contributions of obesity, diabetes mellitus, genetics, and sleep apnea on the pulmonary circulation in those with PH-HFpEF, and we discuss the potential role of exercise testing or fluid challenge during diagnostic testing.

Left Atrial Intrinsic Strain Rate Correcting for Pulmonary Wedge Pressure Is Accurate in Estimating Pulmonary Vascular Resistance in Breathless Patients

OBJECTIVES

We hypothesized that left atrial deformation during atrial systole (LASRa) correlates with pulmonary capillary wedge pressure (PCWP), thus enabling echo-derived pulmonary vascular resistance (PVR) estimation in a wide range of different subsets of patients.

BACKGROUND

Various etiologies of pulmonary hypertension (PH) have different mechanisms and treatments for breathlessness. Irrespective of the location of the underlying pulmonary vascular pathology, pre- or postcapillary, the resulting PH is fairly easy to assess by Doppler echocardiography, but PVR remains a challenge.

METHODS

We prospectively included 46 patients (mean age 61 ± 13 years) in sinus rhythm, who underwent right heart catheterization because of dyspnea. According to the NICE guidelines classification, 22 belonged to group 1 pulmonary artery hypertension (PAH), 19 belonged to group 2 congestive heart failure (CHF), 1 belonged to group 4 chronic thromboembolic pulmonary hypertension (CTEPH), and 4 had normal hemodynamics. Simultaneous Doppler echocardiography using spectral, tissue Doppler, and speckle tracking echocardiography techniques for assessing LA structure and function was performed.

RESULTS

PCWPrhc correlated with LASRa (r(2) = 0.65, P < 0.001). PCWPecho was calculated using the equation (PCWPecho = 26.12 - 11.09 × LASRa), and the resulting PVR echo strongly correlated with the respective catheter-based measurements PVRrhc (r(2) = 0.69. P < 0.001) with a sensitivity of 85% and specificity of 74% identifying a PVR ≥ 3 WU.

CONCLUSIONS

Left atrial strain rate during atrial systole correlates closely with pulmonary capillary wedge pressure and consequently the calculated pulmonary vascular resistance, irrespective of the etiology of PH.

Understanding Heart Failure

Heart failure (HF) is a growing global health concern that affects more than 20 million people worldwide. With an ever-growing segment of the population over the age of 65, the prevalence of HF and its associated costs are expected to increase exponentially over the next decade. Advances in the understanding of the pathophysiology and treatment of HF have resulted in the ability to enhance both the quantity and the quality of life of patients with HF. This article reviews the current understanding of the pathophysiology, cause, classification, and treatment of HF and describes areas of uncertainty that demand future study.

Cardio-Pulmonary-Renal Interactions: A Multidisciplinary Approach

Over the past decade, science has greatly advanced our understanding of interdependent feedback mechanisms involving the heart, lung, and kidney. Organ injury is the consequence of maladaptive neurohormonal activation, oxidative stress, abnormal immune cell signaling, and a host of other mechanisms that precipitate adverse functional and structural changes. The presentation of interorgan crosstalk may include an acute, chronic, or acute on chronic timeframe. We review the current, state-of-the-art understanding of cardio-pulmonary-renal interactions and their related pathophysiology, perpetuating nature, and cycles of increased susceptibility and reciprocal progression. To this end, we present a multidisciplinary approach to frame the diverse spectrum of published observations on the topic. Assessment of organ functional reserve and use of biomarkers are valuable clinical strategies to screen and detect disease, assist in diagnosis, assess prognosis, and predict recovery or progression to chronic disease.

Pulmonary hypertension in heart failure with preserved ejection fraction

In heart failure with preserved ejection fraction (HFpEF), an entity that remains challenging and difficult to treat, the development of pulmonary hypertension (PH), via an increase in left atrial pressure, is the direct consequence of reduced relaxation and enhanced stiffness of the left ventricle and is now viewed as an important contributor to clinical worsening and increased mortality. PH becomes a relevant clinical phenotype in approximately 50% of patients with HFpEF and represents a true challenge in the clinical follow-up and management of these patients. Along with these epidemiologic insights, there has been increasing recognition of the pathophysiology of PH and its consequences on the right ventricle in patients with HFpEF. Novel and effective therapeutic interventions aimed at preventing and reversing PH are highly relevant in the attempt to modify the poor clinical trajectory and growing health care burden of HFpEF. Many theoretical rationales as well as progressively accumulating evidence support the usefulness of nitric oxide pathway-potentiating compounds in targeting the lung vasculature through phosphodiesterase 5 inhibitors or guanylate cyclase stimulators to produce vasodilation and potentially a biologic effect. These pharmacologic strategies may be clinically effective options for the treatment of PH in patients with HFpEF; however, large controlled trials are necessary to address definitively the safety, tolerability, and potential impact on morbidity and mortality. This review details the pathophysiologic process, prevalence, and consequences of HFpEF-associated PH and discusses current and emerging treatment strategies to prevent or treat this deleterious sequela when present.

Pathophysiology and clinical relevance of pulmonary remodelling in pulmonary hypertension due to left heart diseases

Pulmonary hypertension (PH) in left heart disease, classified as group II, is the most common form of PH that occurs in approximately 60% of cases of reduced and preserved left ventricular ejection fraction. Although relatively much is known about hemodynamic stages (passive or reactive) and their consequences on the right ventricle (RV) there is no consensus on the best hemodynamic definition of group II PH. In addition, the main pathways that lead to lung capillary injury and impaired biology of small artery remodelling processes are largely unknown. Typical lung manifestations of an increased pulmonary pressure and progressive RV-pulmonary circulation uncoupling are an abnormal alveolar capillary gas diffusion, impaired lung mechanics (restriction), and exercise ventilation inefficiency. Of several classes of pulmonary vasodilators currently clinically available, oral phosphodiesterase 5 inhibition, because of its strong selectivity for targeting the cyclic guanosine monophosphate pathway in the pulmonary circulation, is increasingly emerging as an attractive opportunity to reach hemodynamic benefits, reverse capillary injury, and RV remodelling, and improve functional capacity. Guanylate cyclase stimulators offer an additional intriguing opportunity but the lack of selectivity and systemic effects might preclude some of the anticipated benefits on the pulmonary circulation. Future trials will determine whether new routes of pharmacologic strategy aimed at targeting lung structural and vascular remodelling might affect morbidity and mortality in left heart disease populations. We believe that this therapeutic goal rather than a pure hemodynamic effect might ultimately emerge as an important challenge for the clinician.