Diagnosis and Treatment of Right Heart Failure in Pulmonary Vascular Diseases: A National Heart, Lung, and Blood Institute Workshop

Venopulmonary extracorporeal membrane oxygenation for right ventricular support as a bridge to lung transplantation: A narrative review

This review evaluates the effectiveness of veno-pulmonary support with an oxygenator using extracorporeal membrane oxygenation as a bridge to lung transplantation strategy in patients undergoing veno-venous extracorporeal membrane oxygenation while awaiting lung transplantation. Examining indications, contraindications, and clinical outcomes, the study highlights potential benefits, drawing insights from successful cases in South Korea and the United States. Despite limited sample sizes, veno-pulmonary support with an oxygenator using extracorporeal membrane oxygenation emerges as a promising approach for further investigation in lung transplantation support. The review emphasizes its role in improving hemodynamic status, preventing complications during extended waiting periods, and presenting a cost-effective alternative to traditional methods, especially in developing countries. While in-hospital mortality rates range from 0% to 10%, comparable to other approaches, cautious optimism surrounds veno-pulmonary support with an oxygenator using extracorporeal membrane oxygenation, urging expanded research to solidify its standing in enhancing patient outcomes, reducing costs, and promoting transplant success.

Incidence of Right Ventricular Dysfunction in an Echocardiographic Referral Cohort

Introduction

Incidence rates (IRs) of RV dysfunction (RVD) are unknown. We examined the rates, risk factors, and heart failure (HF) hospitalization hazard associated with incident RVD in patients referred for Transthoracic Echocardiogram (TTE).

Methods

In this retrospective cohort study, we extracted tricuspid regurgitant velocity (TRV) and tricuspid annular systolic plane excursion (TAPSE) from TTEs at Vanderbilt (2010-2023). We followed patients from their earliest TTE with normal RV function (TAPSE≥17mm) and a reported TRV. The primary outcome was new RVD (TAPSE<17mm), and the secondary outcome was HF hospitalization after second TTE. Poisson regression and multivariable cox models estimated IRs and hazard ratios, adjusted for demographics, comorbidities, and TTE measures.

Results

Among 45,753 patients (63 years [IQR 50-72], 45% Male, 13% Black) meeting inclusion criteria, 13,735 (30.1%) underwent a follow up TTE and 4,198 (9.2%) developed RVD. The IR of RVD in the full cohort was 3.2/100 person/years (95%CI 3.1-3.3) and 8.2 (95%CI 8.0-8.5) in the repeat TTE cohort. IRs increased with rising RVSP. Risk factors for incident RVD were most prominently HF (HR 1.88; 95%CI 1.75-2.03), left-sided valvular disease (HR 1.68; 95%CI 1.53-1.85), and other cardiovascular comorbidities. Baseline RVSP >35 mmHg associated with TAPSE decline over time. Incident RVD increased hazard of HF hospitalization (HR 2.02; 95%CI 1.85-2.21). Hazard of HF hospitalization increased when TAPSE declined by ≥5mm.

Conclusions

RVD incidence is substantial among patients referred for TTE. Clinical monitoring is warranted if RVSP >35mmHg. Cardiovascular comorbidities drive RVD in this population. Incident RVD associates with increased hazard of HF hospitalization.

Pathophysiology of the right ventricle and its pulmonary vascular interaction

The right ventricle and its stress response is perhaps the most important arbiter of survival in patients with pulmonary hypertension of many causes. The physiology of the cardiopulmonary unit and definition of right heart failure proposed in the 2018 World Symposium on Pulmonary Hypertension have proven useful constructs in subsequent years. Here, we review updated knowledge of basic mechanisms that drive right ventricular function in health and disease, and which may be useful for therapeutic intervention in the future. We further contextualise new knowledge on assessment of right ventricular function with a focus on metrics readily available to clinicians and updated understanding of the roles of the right atrium and tricuspid regurgitation. Typical right ventricular phenotypes in relevant forms of pulmonary vascular disease are reviewed and recent studies of pharmacological interventions on chronic right ventricular failure are discussed. Finally, unanswered questions and future directions are proposed.

Defining Echocardiographic Degrees of Right Heart Size and Function in Pulmonary Vascular Disease from the PVDOMICS Study

Background

Defining qualitative grades of echocardiographic metrics of right heart chamber size and function is critical for screening, clinical assessment, and measurement of therapeutic response in individuals with pulmonary vascular disease (PVD). In a population enriched for PVD, we sought to establish qualitative grades and prognostic value of right heart chamber size and function.

Methods

We investigated 1053 study participants in the Redefining Pulmonary Hypertension through PVD Phenomics program (PVDOMICS) to determine clinical and echocardiographic differences associated with increasing pulmonary vascular resistance (PVR) severity. Right heart chamber size and function were qualitatively assessed using a percentile-based approach above the median values to create a clinical grading system for right heart adaptation. The relationship between echocardiographic categories and all-cause mortality was examined using survival analyses adjusted for potential confounders.

Results

A stepwise increase in adverse right heart remodeling was observed with a concomitant decrease in functional parameters by PVR strata (p<0.001 for all). Mild, moderate, and severe categories of right heart chamber size and dysfunction were defined using a percentile-based approach across the spectrum of PVD. During a median follow up of 2.07 years (interquartile range 1.23 - 3.01 years), 130 participants died (11.4%). Progressive PVR increase and 2DE evidence of right heart dysfunction inclusive of fractional area change, and right ventricular (RV) global longitudinal strain were independently associated with increased all-cause mortality risk in multivariate analysis adjusted for age, disease duration and male sex.

Conclusions

In this well-characterized sample of adults with diverse etiologies and varying PVD severity, we define categories of abnormal right heart chamber size and function. Further, we demonstrate a stepwise relationship between these categories of abnormal morphology and function and all-cause mortality. Defining grades of RV dysfunction in individuals with known PVD has important clinical implications for monitoring disease progression and response to therapies.

Prognostic Significance of Proteomics-Discovered Circulating Inflammatory Biomarkers in Patients With Pulmonary Arterial Hypertension

BACKGROUND

Pulmonary arterial hypertension (PAH) ultimately leads to right ventricular failure and premature death. The identification of circulating biomarkers with prognostic utility is considered a priority. As chronic inflammation is recognized as key pathogenic driver, we sought to identify inflammation-related circulating proteins that add incremental value to current risk stratification models for long-term survival in patients with PAH.

METHODS AND RESULTS

Plasma levels of 384 inflammatory proteins were measured with the proximity extension assay technology in patients with PAH (n=60) and controls with normal hemodynamics (n=28). Among these, 51 analytes were significantly overexpressed in the plasma of patients with PAH compared with controls. Cox proportional hazard analyses and C-statistics were performed to assess the prognostic value and the incremental prognostic value of differentially expressed proteins. A panel of 6 proteins (CRIM1 [cysteine rich transmembrane bone morphogenetic protein regulator 1], HGF [hepatocyte growth factor], FSTL3 [follistatin-like 3], PLAUR [plasminogen activator, urokinase receptor], CLSTN2 [calsyntenin 2], SPON1 [spondin 1]) were independently associated with death/lung transplantation at the time of PAH diagnosis after adjustment for the 2015 European Society of Cardiology/European Respiratory Society guidelines, the REVEAL (Registry to Evaluate Early and Long-Term PAH Disease Management) 2.0 risk scores, and the refined 4-strata risk assessment. CRIM1, PLAUR, FSTL3, and SPON1 showed incremental prognostic value on top of the predictive models. As determined by Western blot, FSTL3 and SPON1 were significantly upregulated in the right ventricle of patients with PAH and animal models (monocrotaline-injected and pulmonary artery banding-subjected rats).

CONCLUSIONS

In addition to revealing new actors likely involved in cardiopulmonary remodeling in PAH, our screening identified promising circulating biomarkers to improve risk prediction in PAH, which should be externally confirmed.

Insights Into Differences in Pulmonary Hemodynamics in Hispanic Patients With Pulmonary Arterial Hypertension

Background

Emerging data suggest that Hispanic patients with pulmonary arterial hypertension (PAH) exhibit improved survival rates compared to individuals of other ethnicities with similar baseline hemodynamics. However, the underlying reasons for this survival advantage remain unclear. This study focused on comparing pulmonary hemodynamics in Hispanic and non-Hispanic PAH patients and how these differences may contribute to varied clinical outcomes.

Methods

A retrospective analysis of right heart catheterization data was conducted on a treatment-naive PAH patient cohort from a single center.

Results

Over a 10-year period, a total of 226 PAH patients were identified, of which 138 (61%) were Hispanic and 88 (39%) were non-Hispanic. Hispanic patients presented with lower pulmonary artery pressures, lower pulmonary vascular resistance, and exhibited significantly higher pulmonary arterial compliance (PAc). Hispanic patients had better 5-year survival rates.

Conclusions

This study highlights the importance of exploring phenotypic differences in ethnically diverse PAH cohorts.

Extrapulmonary manifestations of pulmonary arterial hypertension

INTRODUCTION

Extrapulmonary manifestations of pulmonary arterial hypertension (PAH) may play a critical pathobiological role and a deeper understanding will advance insight into mechanisms and novel therapeutic targets. This manuscript reviews our understanding of extrapulmonary manifestations of PAH.

AREAS COVERED

A group of experts was assembled and a complimentary PubMed search performed (October 2023 - March 2024). Inflammation is observed throughout the central nervous system and attempts at manipulation are an encouraging step toward novel therapeutics. Retinal vascular imaging holds promise as a noninvasive method of detecting early disease and monitoring treatment responses. PAH patients have gut flora alterations and dysbiosis likely plays a role in systemic inflammation. Despite inconsistent observations, the roles of obesity, insulin resistance and dysregulated metabolism may be illuminated by deep phenotyping of body composition. Skeletal muscle dysfunction is perpetuated by metabolic dysfunction, inflammation, and hypoperfusion, but exercise training shows benefit. Renal, hepatic, and bone marrow abnormalities are observed in PAH and may represent both end-organ damage and disease modifiers.

EXPERT OPINION

Insights into systemic manifestations of PAH will illuminate disease mechanisms and novel therapeutic targets. Additional study is needed to understand whether extrapulmonary manifestations are a cause or effect of PAH and how manipulation may affect outcomes.

Right Ventricular Dysfunction on Transthoracic Echocardiography and Long-Term Mortality in the Critically Unwell: A Systematic Review and Meta-Analysis

OBJECTIVE

Right ventricular dysfunction (RVD) is common in the critically ill. To date studies exploring RVD sequelae have had heterogenous definitions and diagnostic methods, with limited follow-up. Additionally much literature has been pathology specific, limiting applicability to the general critically unwell patient.

METHOD AND STUDY DESIGN

We conducted a systematic review and meta-analysis to evaluate the impact of RVD diagnosed with transthoracic echocardiography (TTE) on long-term mortality in unselected critically unwell patients compared to those without RVD. A systematic search of EMBASE, Medline and Cochrane was performed from inception to March 2022. All RVD definitions using TTE were included. Patients were those admitted to a critical or intensive care unit, irrespective of disease processes. Long-term mortality was defined as all-cause mortality occurring at least 30 days after hospital admission. A priori subgroup analyses included disease specific and delayed mortality (death after hospital discharge/after the 30th day from hospital admission) in patients with RVD. A random effects model analysis was performed with the Dersimionian and Laird inverse variance method to generate effect estimates.

RESULTS

Of 5985 studies, 123 underwent full text review with 16 included (n = 3196). 1258 patients had RVD. 19 unique RVD criteria were identified. The odds ratio (OR) for long term mortality with RVD was 2.92 (95% CI 1.92-4.54, I2 76.4%) compared to no RVD. The direction and extent was similar for cardiac and COVID19 subgroups. Isolated RVD showed an increased risk of delayed mortality when compared to isolated left/biventricular dysfunction (OR 2.01, 95% CI 1.05-3.86, I2 46.8%).

CONCLUSION

RVD, irrespective of cause, is associated with increased long term mortality in the critically ill. Future studies should be aimed at understanding the pathophysiological mechanisms by which this occurs. Commonly used echocardiographic definitions of RVD show significant heterogeneity across studies, which contributes to uncertainty within this dataset.

Approach to Decompensated Right Heart Failure in the Acute Setting

Acute right heart failure (ARHF) arises when the right ventricle fails to pump blood efficiently to the pulmonary circulation. This inefficiency leads to a decreased blood supply to various organs. ARHF is a significant health concern, often leading to increased hospital admissions and being associated with a higher risk of mortality. This condition underscores the importance of effective cardiac care and timely intervention to manage its complications and improve patient outcomes. Diagnosing ARHF involves a comprehensive approach that includes a physical examination to evaluate the patient's fluid status and heart-lung function, blood tests to identify potential triggers and help forecast patient outcomes and various imaging techniques. These imaging techniques include electrocardiograms, point-of-care ultrasounds, computed tomography, cardiac magnetic resonance imaging, and other advanced monitoring methods. These diagnostic tools collectively aid in a detailed assessment of the patient's cardiac and pulmonary health, essential for effective management of ARHF. The management of ARHF focuses on addressing the underlying causes, regulating fluid balance, and enhancing cardiac function through pharmacological treatments or mechanical support aimed at boosting right heart performance. This management strategy includes the use of medications that modulate preload, afterload, and inotropy; vasopressors; anti-arrhythmic drugs; ensuring proper oxygenation and ventilation; and the utilization of heart and lung assist devices as a bridge to potential transplantation. This review article is dedicated to exploring the pathophysiology of ARHF, examining its associated morbidity and mortality, evaluating the various diagnostic tools available, and discussing the diverse treatment modalities. The article seeks to provide a comprehensive understanding of ARHF, its impact on health, and the current strategies for its management.

Classification and Predictors of Right Ventricular Functional Recovery in Pulmonary Arterial Hypertension

BACKGROUND

Normative changes in right ventricular (RV) structure and function have not been characterized in the context of treatment-associated functional recovery (RV functional recovery [RVFnRec]). The aim of this study is to assess the clinical relevance of a proposed RVFnRec definition.

METHODS

We evaluated 63 incident patients with pulmonary arterial hypertension by right heart catheterization and cardiac magnetic resonance imaging at diagnosis and cardiac magnetic resonance imaging and invasive cardiopulmonary exercise testing following treatment (≈11 months). Sex, age, ethnicity matched healthy control subjects (n=62) with 1-time cardiac magnetic resonance imaging and noninvasive cardiopulmonary exercise testing were recruited from the PVDOMICS (Redefining Pulmonary Hypertension through Pulmonary Vascular Disease Phenomics) project. We examined therapeutic cardiac magnetic resonance imaging changes relative to the evidence-based peak oxygen consumption (VO2peak)>15 mL/(kg·min) to define RVFnRec by receiver operating curve analysis. Afterload was measured as mean pulmonary artery pressure, resistance, compliance, and elastance.

RESULTS

A drop in RV end-diastolic volume of -15 mL best defined RVFnRec (area under the curve, 0.87; P=0.0001) and neared upper 95% CI RV end-diastolic volume of controls. This cutoff was met by 22 out of 63 (35%) patients which was reinforced by freedom from clinical worsening, RVFnRec 1 out of 21 (5%) versus no RVFnRec 17 out of 42, 40% (log-rank P=0.006). A therapy-associated increase of 0.8 mL/mm Hg in compliance had the best predictive value of RVFnRec (area under the curve, 0.76; [95% CI, 0.64-0.88]; P=0.001). RVFnRec patients had greater increases in stroke volume, and cardiac output at exercise.

CONCLUSIONS

RVFnRec defined by RV end-diastolic volume therapeutic decrease of -15 mL predicts exercise capacity, freedom from clinical worsening, and nears normalization. A therapeutic improvement of compliance is superior to other measures of afterload in predicting RVFnRec. RVFnRec is also associated with increased RV output reserve at exercise.

Classification and Predictors of Right Ventricular Functional Recovery in Pulmonary Arterial Hypertension

Background

Normative changes in right ventricular (RV) structure and function have not been characterized in the context of treatment-associated functional recovery (RVFnRec). The aim of this study is to assess the clinical relevance of a proposed RVFnRec definition.

Methods

We evaluated 63 incident patients with PAH by right heart catheterization and cardiac MRI (CMR) at diagnosis and CMR and invasive cardiopulmonary exercise (CPET) following treatment (∼11 months). Sex, age, race/ethnicity matched healthy control subjects (n=62) with one-time CMR and non-invasive CPET were recruited from the PVDOMICS project. We examined therapeutic CMR changes relative to the evidence-based peak oxygen consumption (VO2 peak )>15mL/kg/min to define RVFnRec by receiver operating curve analysis. Afterload was measured in the as mean pulmonary artery pressure, resistance, compliance, and elastance.

Results

A drop in RV end-diastolic volume of -15 mL best defined RVFnRec (AUC 0.87, P=0.0001) and neared upper 95% CI RVEDV of controls. 22/63 (35%) of subjects met this cutoff which was reinforced by freedom from clinical worsening, RVFnRec 1/21 (5%) versus no RVFnRec 17/42, 40%, (log rank P=0.006). A therapy-associated increase of 0.8 mL/mmHg in compliance had the best predictive value of RVFnRec (AUC 0.76, CI 0.64-0.88, P=0.001). RVFnRec subjects had greater increases in stroke volume, and cardiac output at exercise.

Conclusions

RVFnRec defined by RVEDV therapeutic decrease of -15mL predicts exercise capacity, freedom from clinical worsening, and nears normalization. A therapeutic improvement of compliance is superior to other measures of afterload in predicting RVFnRec. RVFnRec is also associated with increased RV output reserve at exercise.

Clinical Perspective

What is new?: Right ventricular functional recovery (RVFnRec) represents a novel endpoint of therapeutic success in PAH. We define RVFnRec as treatment associated normative RV changes related to function (peak oxygen consumption). Normative RV imaging changes are compared to a well phenotyped age, sex, and race/ethnicity matched healthy control cohort from the PVDOMICS project. Previous studies have focused on RV ejection fraction improvements. However, we show that changes in RVEDV are perhaps more important in that improvements in LV function also occur. Lastly, RVFnRec is best predicted by improvements in pulmonary artery compliance versus pulmonary vascular resistance, a more often cited metric of RV afterload.What are the clinical implications?: RVFnRec represents a potential non-invasive assessment of clinical improvement and therapeutic response. Clinicians with access to cardiac MRI can obtain a limited scan (i.e., ventricular volumes) before and after treatment. Future study should examine echocardiographic correlates of RVFnRec.

Right ventricular function across the spectrum of health and disease

Knowledge of right ventricular (RV) structure and function has historically lagged behind that of the left ventricle (LV). However, advancements in invasive and non-invasive evaluations, combined with epidemiological analyses, have advanced the current understanding of RV (patho)physiology across the spectrum of health and disease, and reinforce the centrality of the RV in contributing to clinical outcomes. In the healthy heart, ventricular-arterial coupling is preserved during rest and in response to increased myocardial demand (eg, exercise) due to substantial RV contractile reserve. However, prolonged exposure to increased myocardial demand, such as endurance exercise, may precipitate RV dysfunction, suggesting that unlike the LV, the RV is unable to sustain high levels of contractility for extended periods of time. Emerging data increasingly indicate that both LV and RV function contribute to clinical heart failure. Reductions in quality-of-life, functional capacity and overall clinical outcomes are worsened among patients with heart failure when there is evidence of RV dysfunction. In addition, the RV is adversely impacted by pulmonary vascular disease, and among affected patients, overall RV function differs based on mechanisms of the underlying pulmonary hypertension, which may result from variations in sarcomere function within RV cardiomyocytes.

A Comprehensive Assessment of Right Ventricular Function in Chronic Thromboembolic Pulmonary Hypertension

While chronic thromboembolic pulmonary hypertension (CTEPH) results from macroscopic and microscopic obstruction of the pulmonary vascular bed, the function of the right ventricle (RV) and increased RV afterload are the main determinants of its symptoms and prognosis. In this review, we assess RV function in patients diagnosed with CTEPH with a focus on the contributions of RV afterload and dysfunction to the pathogenesis of this disease. We will also discuss changes in RV function and geometry in response to treatment, including medical therapy, pulmonary endarterectomy, and balloon pulmonary angioplasty.

Coronary blood flow in heart failure: cause, consequence and bystander

Heart failure is a clinical syndrome where cardiac output is not sufficient to sustain adequate perfusion and normal bodily functions, initially during exercise and in more severe forms also at rest. The two most frequent forms are heart failure of ischemic origin and of non-ischemic origin. In heart failure of ischemic origin, reduced coronary blood flow is causal to cardiac contractile dysfunction, and this is true for stunned and hibernating myocardium, coronary microembolization, myocardial infarction and post-infarct remodeling, possibly also for the takotsubo syndrome. The most frequent form of non-ischemic heart failure is dilated cardiomyopathy, caused by genetic mutations, myocarditis, toxic agents or sustained tachyarrhythmias, where alterations in coronary blood flow result from and contribute to cardiac contractile dysfunction. Hypertrophic cardiomyopathy is caused by genetic mutations but can also result from increased pressure and volume overload (hypertension, valve disease). Heart failure with preserved ejection fraction is characterized by pronounced coronary microvascular dysfunction, the causal contribution of which is however not clear. The present review characterizes the alterations of coronary blood flow which are causes or consequences of heart failure in its different manifestations. Apart from any potentially accompanying coronary atherosclerosis, all heart failure entities share common features of impaired coronary blood flow, but to a different extent: enhanced extravascular compression, impaired nitric oxide-mediated, endothelium-dependent vasodilation and enhanced vasoconstriction to mediators of neurohumoral activation. Impaired coronary blood flow contributes to the progression of heart failure and is thus a valid target for established and novel treatment regimens.