A roadmap for therapeutic discovery in pulmonary hypertension associated with left heart failure. A scientific statement of the Heart Failure Association (HFA) of the ESC and the ESC Working Group on Pulmonary Circulation & Right Ventricular Function

Pulmonary hypertension (PH) associated with left heart failure (LHF) (PH-LHF) is one of the most common causes of PH. It directly contributes to symptoms and reduced functional capacity and negatively affects right heart function, ultimately leading to a poor prognosis. There are no specific treatments for PH-LHF, despite the high number of drugs tested so far. This scientific document addresses the main knowledge gaps in PH-LHF with emphasis on pathophysiology and clinical trials. Key identified issues include better understanding of the role of pulmonary venous versus arteriolar remodelling, multidimensional phenotyping to recognize patient subgroups positioned to respond to different therapies, and conduct of rigorous pre-clinical studies combining small and large animal models. Advancements in these areas are expected to better inform the design of clinical trials and extend treatment options beyond those effective in pulmonary arterial hypertension. Enrichment strategies, endpoint assessments, and thorough haemodynamic studies, both at rest and during exercise, are proposed to play primary roles to optimize early-stage development of candidate therapies for PH-LHF.

Toward a Universal Definition of Etiologies in Heart Failure: Categorizing Causes and Advancing Registry Science

Heart failure (HF) is a well-described final common pathway for a broad range of diseases however substantial confusion exists regarding how to describe, study, and track these underlying etiologic conditions. We describe (1) the overlap in HF etiologies, comorbidities, and case definitions as currently used in HF registries led or managed by members of the global HF roundtable; (2) strategies to improve the quality of evidence on etiologies and modifiable risk factors of HF in registries; and (3) opportunities to use clinical HF registries as a platform for public health surveillance, implementation research, and randomized registry trials to reduce the global burden of noncommunicable diseases. Investment and collaboration among countries to improve the quality of evidence in global HF registries could contribute to achieving global health targets to reduce noncommunicable diseases and overall improvements in population health.

Venous Tone and Stressed Blood Volume in Heart Failure: JACC Review Topic of the Week

A number of pathologic processes contribute to the elevation in cardiac filling pressures in heart failure (HF), including myocardial dysfunction and primary volume overload. In this review, we discuss the important role of the venous system and the concepts of stressed blood volume and unstressed blood volume. We review how regulation of venous tone modifies the distribution of blood between these 2 functional compartments, the physical distribution of blood between the pulmonary and systemic circulations, and how these relate to the hemodynamic abnormalities observed in HF. Finally, we review recently applied methods for estimating stressed blood volume and how they are being applied to the results of clinical studies to provide new insights into resting and exercise hemodynamics and therapeutics for HF.

Levosimendan in intensive care and emergency medicine: literature update and expert recommendations for optimal efficacy and safety

The inodilator levosimendan, in clinical use for over two decades, has been the subject of extensive clinical and experimental evaluation in various clinical settings beyond its principal indication in the management of acutely decompensated chronic heart failure. Critical care and emergency medicine applications for levosimendan have included postoperative settings, septic shock, and cardiogenic shock. As the experience in these areas continues to expand, an international task force of experts from 15 countries (Austria, Belgium, China, Croatia, Finland, France, Germany, Greece, Hungary, Italy, the Netherlands, Spain, Sweden, Switzerland, and the USA) reviewed and appraised the latest additions to the database of levosimendan use in critical care, considering all the clinical studies, meta-analyses, and guidelines published from September 2019 to November 2021. Overall, the authors of this opinion paper give levosimendan a "should be considered" recommendation in critical care and emergency medicine settings, with different levels of evidence in postoperative settings, septic shock, weaning from mechanical ventilation, weaning from veno-arterial extracorporeal membrane oxygenation, cardiogenic shock, and Takotsubo syndrome, in all cases when an inodilator is needed to restore acute severely reduced left or right ventricular ejection fraction and overall haemodynamic balance, and also in the presence of renal dysfunction/failure.

Prevalence, incidence, and survival of pulmonary arterial hypertension: A systematic review for the global burden of disease 2020 study

Pulmonary arterial hypertension (PAH) is characterized by increased resistance in the pulmonary arterioles as a result of remodeled blood vessels. We sought all available epidemiologic data on population‐based prevalence, incidence, and 1‐year survival of PAH as part of the Global Burden of Disease Study. We performed a systematic review searching Global Index Medicus (GIM) for keywords related to PAH between 1980 and 2021 and identified population‐representative sources of prevalence, incidence, and mortality for clinically diagnosed PAH. Of 6772 articles identified we found 65 with population‐level data: 17 for prevalence, 17 for incidence, and 58 reporting case fatality. Reported prevalence ranged from 0.37 cases/100,000 persons in a referral center of French children to 15 cases/100,000 persons in an Australian study. Reported incidence ranged from 0.008 cases/100,000 person‐years in Finland, to 1.4 cases/100,000 person‐years in a retrospective chart review at a clinic in Utah, United States. Reported 1‐year survival ranged from 67% to 99%. All studies with sex‐specific estimates of prevalence or incidence reported higher levels in females than males. Studies varied in their size, study design, diagnostic criteria, and sampling procedures. Reported PAH prevalence, incidence, and mortality varied by location and study. Prevalence ranged from 0.4 to 1.4 per 100,000 persons. Harmonization of methods for PAH registries would improve efforts at disease surveillance. Results of this search contribute to ongoing efforts to quantify the global burden of PAH.

EXPRESS: Prevalence, Incidence, and Survival of Pulmonary Arterial Hypertension: A Systematic Review for the Global Burden of Disease 2020 Study

Background: Pulmonary arterial hypertension (PAH) is characterized by increased resistance in the pulmonary arterioles as a result of remodeled blood vessels. We sought to establish the baseline level of PAH by assembling all available epidemiologic data on population-based prevalence, incidence, and one-year survival of PAH as part of the Global Burden of Disease Study.

Methods: We performed a systematic review searching Global Index Medicus (GIM) for key words related to PAH between 1980 and 2021, and identified population-representative sources of prevalence, incidence, and mortality for clinically diagnosed PAH.

Results: Of 6,772 identified we found 65 with population-level data: 17 for prevalence, 17 for incidence, and 58 reporting case fatality. Reported prevalence ranged from 0.37 cases/100,000 persons in a referral center of French children to 150 cases/100,000 persons in an Australian echocardiography study. Reported incidence ranged from 0.008 cases/100,000 person-years in a study of hospital discharge records in Finland, to 1.4 cases/100,000 person-years in a retrospective chart review at a clinic in Utah, USA. Reported one-year survival ranged from 67% to 99%. All studies with sex-specific estimates reported higher levels in females than males. Studies varied in their size, study design, diagnostic criteria, and sampling procedures.

Conclusions: Reported PAH prevalence, incidence, and mortality varied by location and study. Prevalence ranged from 0.4 to 1.4 per 100,000 persons. Harmonization of methods for PAH registries would improve efforts at disease surveillance. Results of this search contribute to ongoing efforts to quantify the global burden of PAH.

Levosimendan-induced venodilation is mediated by opening of potassium channels

Unique vascular responses adhere to the cardiovascular efficacy of the inodilator levosimendan. In particular, selective venodilation appears to explain its clinical benefit during pulmonary hypertension complicated by heart failure with preserved ejection fraction. Vasodilators increase vessel diameter in various parts of the vascular system to different degrees and thereby influence blood pressure, its distribution, and organ perfusion depending on their mechanisms of action. Levosimendan and its long‐lived active metabolite OR‐1896 mobilize a set of vasodilatory mechanisms, that is, the opening of the ATP‐sensitive K⁺ channels and other K⁺ channels on top of a highly selective inhibition of the phosphodiesterase III enzyme. A vessel‐specific combination of the above vasodilator mechanisms—in concert with cardiac effects and cardiovascular reflex regulations—illustrates the pharmacological profile of levosimendan in various cardiovascular disorders. While levosimendan has been known to be an inotrope, its properties as an activator of ATP‐sensitive K⁺ channels have gone largely ignored with respect to clinical applications. Here, we provide a summary of what is known about the ATP‐sensitive K⁺ channel properties in preclinical studies and now for the first time, its ATP‐sensitive K⁺ channel properties in a clinical trial.

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

Right ventricular dysfunction is a hallmark of advanced pulmonary vascular, lung parenchymal, and left heart disease, yet the underlying mechanisms that govern (mal)adaptation remain incompletely characterized. Owing to the knowledge gaps in our understanding of the right ventricle (RV) in health and disease, the National Heart, Lung, and Blood Institute (NHLBI) commissioned a working group to identify current challenges in the field. These included a need to define and standardize normal RV structure and function in populations; access to RV tissue for research purposes and the development of complex experimental platforms that recapitulate the in vivo environment; and the advancement of imaging and invasive methodologies to study the RV within basic, translational, and clinical research programs. Specific recommendations were provided, including a call to incorporate precision medicine and innovations in prognosis, diagnosis, and novel RV therapeutics for patients with pulmonary vascular disease.

A13 Phylodynamic analysis of HIV in Florida

We are interested in using phylodynamics to better understand molecular clusters of HIV within the state of Florida, USA. To our knowledge, there is currently no study using such methodology to understand the epidemic in Florida. Viral sequences collected from 2007 to 2017 (about 50,000) will be linked with individual-level data (demographics—sex, race/ethnicity—and mode of transmission) accessed through the Patient Reporting Investigating Surveillance Manager (PRISM), and the Enhanced HIV/AIDS Reporting System (eHARS) via the Florida Department of Health (FDOH). Through the use of HIV-TRACE, which analyzes genetic distance matrices, we will create molecular transmission networks including data on mode of transmission, race/ethnicity, and sex. Furthermore, a maximum likelihood phylogenetic tree will be created using software (e.g. IQ-Tree, PhyML, and FastTree2) run on a high-performance cluster. Phylogenetic comparative analysis will be performed to assess the association between phylogenetic clades and demographics (including extended demographics like syphilis and other comorbidities queried from PRISM and eHARS).

The use of a durable right ventricular assist device for isolated right ventricular failure due to combined pre- and postcapillary pulmonary hypertension

Patients with isolated right ventricular (RV) failure have poor outcomes and minimal treatment options. We report a case where a durable RV assist device (RVAD) was implanted for end-stage RV failure from combined pre- and postcapillary pulmonary hypertension (PH) due in part to chronic thromboembolic PH using a temporary percutaneous RVAD as a bridging strategy. While the patient ultimately died from non-cardiovascular causes, there was significant improvement in markers of cardiogenic shock and hemodynamic RV function parameters without adverse effects from increased pulmonary artery pressures. More research is needed to identify an appropriate long-term mechanical support strategy for this patient population.

Are anticoagulants still indicated in pulmonary arterial hypertension?

Pulmonary arterial hypertension (PAH) is a type of pulmonary hypertension that is a progressive, fatal disease. Multiple underlying mechanisms for PAH have been identified, including vasoconstriction, intimal proliferation, medial hypertrophy, inflammation, mitochondrial dysfunction, and in situ thrombosis. Because it is an uncommon disease, it has been challenging to identify a specific treatment that targets the dominant disease mechanism in a given patient. Early success demonstrating that some patients (approximately 10%) possess pulmonary vasoreactivity at diagnosis has driven the development of pulmonary vasodilators as the mainstay of treatment. However, while they improve exercise tolerance in clinical trials, their effect on survival is limited. Therapies that target underlying disease mechanisms that affect a majority of patients are clearly needed if we are to significantly improve overall survival.

In the actual guidelines, chronic anticoagulation is no longer recommended in patients with idiopathic, hereditary, and drug-induced PAH although there is much indirect evidence for this.

There are data from over 40 years which include: (1) pathology studies showing the presence of thrombotic lesions in a majority of patients with PAH, both idiopathic and associated with many other conditions; (2) a similar frequency of thrombotic lesions in patients treated with pulmonary vasodilators as was seen in the years before their use; (3) mechanistic studies showing that procoagulant conditions predispose to the development of intraluminal thrombosis that contributes to vascular remodeling and the progressive nature of the pathologic changes; and (4) observational studies that, with one exception, have demonstrated a substantial survival advantage in patients with PAH treated with oral anticoagulation.

Acknowledging that no prospective randomized trial with anticoagulants has ever been done, we recommend a pragmatic approach to the use of anticoagulants in PAH. We suggest that the risks and benefits of chronic anticoagulation be considered in individual patients, and that warfarin be prescribed in patients with PAH, unless they have an increased risk of bleeding.

The question of whether direct oral anticoagulants (DOACs) would provide the same benefit as vitamin K antagonists is valid, but presently there are no data at all regarding their use in PAH. However, in patients with PAH in whom warfarin anticoagulation management proves problematic, it is reasonable to switch the patient to a DOAC as is current practice for other conditions.

Critical Genomic Networks and Vasoreactive Variants in Idiopathic Pulmonary Arterial Hypertension

RATIONALE

Idiopathic pulmonary arterial hypertension (IPAH) is usually without an identified genetic cause, despite clinical and molecular similarity to bone morphogenetic protein receptor type 2 mutation-associated heritable pulmonary arterial hypertension (PAH). There is phenotypic heterogeneity in IPAH, with a minority of patients showing long-term improvement with calcium channel-blocker therapy.

OBJECTIVES

We sought to identify gene variants (GVs) underlying IPAH and determine whether GVs differ in vasodilator-responsive IPAH (VR-PAH) versus vasodilator-nonresponsive IPAH (VN-PAH).

METHODS

We performed whole-exome sequencing (WES) on 36 patients with IPAH: 17 with VR-PAH and 19 with VN-PAH. Wnt pathway differences were explored in human lung fibroblasts.

MEASUREMENTS AND MAIN RESULTS

We identified 1,369 genes with 1,580 variants unique to IPAH. We used a gene ontology approach to analyze variants and identified overrepresentation of several pathways, including cytoskeletal function and ion binding. By mapping WES data to prior genome-wide association study data, Wnt pathway genes were highlighted. Using the connectivity map to define genetic differences between VR-PAH and VN-PAH, we found enrichment in vascular smooth muscle cell contraction pathways and greater genetic variation in VR-PAH versus VN-PAH. Using human lung fibroblasts, we found increased stimulated Wnt activity in IPAH versus controls.

CONCLUSIONS

A pathway-based analysis of WES data in IPAH demonstrated multiple rare GVs that converge on key biological pathways, such as cytoskeletal function and Wnt signaling pathway. Vascular smooth muscle contraction-related genes were enriched in VR-PAH, suggesting a potentially different genetic predisposition for VR-PAH. This pathway-based approach may be applied to next-generation sequencing data in other diseases to uncover the contribution of unexpected or multiple GVs to a phenotype.

Enhancing Insights into Pulmonary Vascular Disease through a Precision Medicine Approach. A Joint NHLBI-Cardiovascular Medical Research and Education Fund Workshop Report

The Division of Lung Diseases of the NHLBI and the Cardiovascular Medical Education and Research Fund held a workshop to discuss how to leverage the anticipated scientific output from the recently launched "Redefining Pulmonary Hypertension through Pulmonary Vascular Disease Phenomics" (PVDOMICS) program to develop newer approaches to pulmonary vascular disease. PVDOMICS is a collaborative, protocol-driven network to analyze all patient populations with pulmonary hypertension to define novel pulmonary vascular disease (PVD) phenotypes. Stakeholders, including basic, translational, and clinical investigators; clinicians; patient advocacy organizations; regulatory agencies; and pharmaceutical industry experts, joined to discuss the application of precision medicine to PVD clinical trials. Recommendations were generated for discussion of research priorities in line with NHLBI Strategic Vision Goals that include: (1) A national effort, involving all the stakeholders, should seek to coordinate biosamples and biodata from all funded programs to a web-based repository so that information can be shared and correlated with other research projects. Example programs sponsored by NHLBI include PVDOMICS, Pulmonary Hypertension Breakthrough Initiative, the National Biological Sample and Data Repository for PAH, and the National Precision Medicine Initiative. (2) A task force to develop a master clinical trials protocol for PVD to apply precision medicine principles to future clinical trials. Specific features include: (a) adoption of smaller clinical trials that incorporate biomarker-guided enrichment strategies, using adaptive and innovative statistical designs; and (b) development of newer endpoints that reflect well-defined and clinically meaningful changes. (3) Development of updated and systematic variables in imaging, hemodynamic, cellular, genomic, and metabolic tests that will help precisely identify individual and shared features of PVD and serve as the basis of novel phenotypes for therapeutic interventions.

Persistence of complex vascular lesions despite prolonged prostacyclin therapy of pulmonary arterial hypertension

AIMS

Continuous infusion of prostacyclin analogues improves survival in advanced pulmonary arterial hypertension. In addition to its vasodilatory effects, prostacyclin has the potential to decrease inflammation, thrombosis, and smooth muscle proliferation. The aim of this retrospective study was to determine whether pathological data support the ability of prostanoids to prevent progression of vascular disease.

METHODS AND RESULTS

Twenty-two autopsied patients with World Health Organization category 1 pulmonary arterial hypertension (primarily idiopathic and connective tissue disease-associated) were divided into those who received long-term prostacyclin (n = 12, PG-long, mean treatment 3.9 years) and those who received 0-1 month of prostacyclin (n = 10, PG-short). Surprisingly, PG-long patients had larger plexiform lesions (P < 0.05), with no decrease in medial and intimal thicknesses as compared with PG-short patients. Plexiform lesion size and density increased with increasing treatment time. Also, PG-long patients had fewer platelet thrombi and more frequent acute diffuse alveolar haemorrhage. Quantification of macrophages and T cells revealed no differences in inflammatory infiltrates.

CONCLUSION

Although long-term prostacyclin therapy may have an antithrombotic effect in addition to its vasodilatory actions, it was not associated with the prevention of advanced vascular lesions. The mechanism by which prostacyclin analogues improve survival in pulmonary arterial hypertension remains uncertain.

Persistence of complex vascular lesions despite prolonged prostacyclin therapy of pulmonary arterial hypertension

AIMS

Continuous infusion of prostacyclin analogues improves survival in advanced pulmonary arterial hypertension. In addition to its vasodilatory effects, prostacyclin has the potential to decrease inflammation, thrombosis, and smooth muscle proliferation. The aim of this retrospective study was to determine whether pathological data support the ability of prostanoids to prevent progression of vascular disease.

METHODS AND RESULTS

Twenty-two autopsied patients with World Health Organization category 1 pulmonary arterial hypertension (primarily idiopathic and connective tissue disease-associated) were divided into those who received long-term prostacyclin (n = 12, PG-long, mean treatment 3.9 years) and those who received 0-1 month of prostacyclin (n = 10, PG-short). Surprisingly, PG-long patients had larger plexiform lesions (P < 0.05), with no decrease in medial and intimal thicknesses as compared with PG-short patients. Plexiform lesion size and density increased with increasing treatment time. Also, PG-long patients had fewer platelet thrombi and more frequent acute diffuse alveolar haemorrhage. Quantification of macrophages and T cells revealed no differences in inflammatory infiltrates.

CONCLUSION

Although long-term prostacyclin therapy may have an antithrombotic effect in addition to its vasodilatory actions, it was not associated with the prevention of advanced vascular lesions. The mechanism by which prostacyclin analogues improve survival in pulmonary arterial hypertension remains uncertain.

Comparison of molecular detection methods for pertussis in children during a state-wide outbreak

A state-wide pertussis outbreak occurred in Washington during the winter–spring months of 2012, concurrent with respiratory viral season. We compared performance characteristics of a laboratory-developed pertussis PCR (LD-PCR for Bordetella pertussis, Bordetella parapertussis, and Bordetella holmesii) and rapid multiplex PCR (RM-PCR) for respiratory viruses (FilmArray™, BioFire, B. pertussis data unblinded following FDA approval post outbreak). We analyzed three cohorts of patients using physician testing orders as a proxy for clinical suspicion for pertussis or respiratory viruses: Cohort 1, tested by LD-PCR for pertussis pathogens only by nasopharyngeal swab; Cohort 2, by RM-PCR for respiratory viruses only by mid-nasal turbinate swab; and Cohort 3, by both methods. B. pertussis was detected in a total of 25 of the 490 patients in Cohort 3 in which LD-PCR detected 20/25 (80 %) cases and the RM-PCR detected 24/25 (96 %; p = 0.2). Pertussis pathogens were detected in 21/584 (3.6 %) of samples from Cohort 1 where clinicians had a relatively strong suspicion for pertussis. In contrast, B. pertussis was detected in only 4/3071 (0.1 %) specimens from Cohort 2 where suspicion for pertussis was lower (p < 0.001 for comparison with Cohort 1). In summary, the two laboratory methods were comparable for the detection of B. pertussis.

Peripheral blood signature of vasodilator-responsive pulmonary arterial hypertension

BACKGROUND

Heterogeneity in response to treatment of pulmonary arterial hypertension (PAH) is a major challenge to improving outcome in this disease. Although vasodilator-responsive PAH (VR-PAH) accounts for a minority of cases, VR-PAH has a pronounced response to calcium channel blockers and better survival than vasodilator-nonresponsive PAH (VN-PAH). We hypothesized that VR-PAH has a different molecular cause from VN-PAH that can be detected in the peripheral blood.

METHODS AND RESULTS

Microarrays of cultured lymphocytes from VR-PAH and VN-PAH patients followed at Vanderbilt University were performed with quantitative polymerase chain reaction performed on peripheral blood for the 25 most different genes. We developed a decision tree to identify VR-PAH patients on the basis of the results with validation in a second VR-PAH cohort from the University of Chicago. We found broad differences in gene expression patterns on microarray analysis including cell-cell adhesion factors and cytoskeletal and rho-GTPase genes. Thirteen of 25 genes tested in whole blood were significantly different: EPDR1, DSG2, SCD5, P2RY5, MGAT5, RHOQ, UCHL1, ZNF652, RALGPS2, TPD52, MKNL1, RAPGEF2, and PIAS1. Seven decision trees were built with the use of expression levels of 2 genes as the primary genes: DSG2, a desmosomal cadherin involved in Wnt/β-catenin signaling, and RHOQ, which encodes a cytoskeletal protein involved in insulin-mediated signaling. These trees correctly identified 5 of 5 VR-PAH patients in the validation cohort.

CONCLUSIONS

VR-PAH and VN-PAH can be differentiated with the use of RNA expression patterns in peripheral blood. These differences may reflect different molecular causes of the 2 PAH phenotypes. This biomarker methodology may identify PAH patients who have a favorable treatment response.

[Pulmonary arterial hypertension: epidemiology and registries]

Registries of patients with pulmonary arterial hypertension (PAH) have been instrumental in characterizing the presentation and natural history of the disease and provide a basis for prognostication. Since the initial accumulation of data conducted in the 1980s, subsequent registry databases have yielded information about the demographic factors, treatment, and survival of patients and have permitted comparisons between populations in different eras and environments. Inclusion of patients with all subtypes of PAH has also allowed comparisons of these subpopulations. We describe herein the basic methodology by which PAH registries have been conducted, review key insights provided by registries, summarize issues related to interpretation and comparison of the results, and discuss the utility of data to predict survival outcomes. Potential sources of bias, particularly related to the inclusion of incident and/or prevalent patients and missing data, are addressed. A fundamental observation of current registries is that survival in the modern treatment era has improved compared with that observed previously and that outcomes among PAH subpopulations vary substantially. Continuing systematic clinical surveillance of PAH will be important as treatment evolves and as understanding of mechanisms advance. Considerations for future directions of registry studies include enrollment of a broader population of patients with pulmonary hypertension of all clinical types and severity and continued globalization and collaboration of registry databases. (J Am Coil Cardiol 2013;62:D51-9) ©2013 by the American College of Cardiology Foundation.

Pharmacologic therapy for pulmonary arterial hypertension in adults: CHEST guideline and expert panel report

OBJECTIVE

Choices of pharmacologic therapies for pulmonary arterial hypertension (PAH) are ideally guided by high-level evidence. The objective of this guideline is to provide clinicians advice regarding pharmacologic therapy for adult patients with PAH as informed by available evidence.

METHODS

This guideline was based on systematic reviews of English language evidence published between 1990 and November 2013, identified using the MEDLINE and Cochrane Library databases. The strength of available evidence was graded using the Grades of Recommendations, Assessment, Development, and Evaluation methodology. Guideline recommendations, or consensus statements when available evidence was insufficient to support recommendations, were developed using a modified Delphi technique to achieve consensus.

RESULTS

Available evidence is limited in its ability to support high-level recommendations. Therefore, we drafted consensus statements to address many clinical questions regarding pharmacotherapy for patients with PAH. A total of 79 recommendations or consensus statements were adopted and graded.

CONCLUSIONS

Clinical decisions regarding pharmacotherapy for PAH should be guided by high-level recommendations when sufficient evidence is available. Absent higher level evidence, consensus statements based upon available information must be used. Further studies are needed to address the gaps in available knowledge regarding optimal pharmacotherapy for PAH.

The WHO classification of pulmonary hypertension: A case-based imaging compendium

Pulmonary hypertension (PH) is defined as a resting mean pulmonary artery pressure greater than 25 mmHg. The World Health Organization (WHO) classifies PH into five categories. The WHO nomenclature assumes shared histology and pathophysiology within categories and implies category-specific treatment. Imaging of the heart and pulmonary vasculature is critical to assigning a patient's PH syndrome to the correct WHO category and is also important in predicting outcomes. Imaging studies often reveal that the etiology of PH in a patient reflects contributions from several categories. Overlap between Categories 2 and 3 (left heart disease and lung disease) is particularly common, reflecting shared risk factors. Correct classification of PH patients requires the combination of standard imaging (chest roentgenograms, ventilation-perfusion scans, echocardiography, and the 12-lead electrocardiogram) and advanced imaging (computed tomography, cardiac magnetic resonance imaging, and positron emission tomography). Despite the value of imaging, cardiac catheterization remains the gold standard for quantification of hemodynamics and is required before initiation of PH-specific therapy. These cases illustrate the use of imaging in classifying patients into WHO PH Categories 1-5.

Current practice for determining pulmonary capillary wedge pressure predisposes to serious errors in the classification of patients with pulmonary hypertension

BACKGROUND

Accurate measurement of left ventricular filling pressure is important to distinguish between category 1 pulmonary arterial hypertension (PAH) and category 2 pulmonary hypertension (PH) from left heart diseases (PH-HFpEF). We hypothesized that the common practice of relying on the digitized mean pulmonary capillary wedge pressure (PCWP-digital) results in erroneous recordings, whereas end-expiratory PCWP measurements (PCWP-end Exp) provide a reliable surrogate measurement for end-expiratory left ventricular end-diastolic pressure (LVEDP-end Exp-end Exp).

METHODS

We prospectively performed left and right cardiac catheterization on 61 patients referred for evaluation of PH and compared the LVEDP-end Exp to end-expiration to the (a) PCWP-end Exp and (b) PCWP-digital.

RESULTS

The PCWP-end Exp was a more reliable reflection of LVEDP-end Exp (mean 13.2 mm Hg vs 12.4 mm Hg; P, nonsignificant) than PCWP-digital (mean 8.0 mm Hg vs 12.4 mm Hg, P < .05). Bland-Altman analysis of PCWP-digital and LVEDP-end Exp revealed a mean bias of -4.4 mm Hg with 95% limits of agreement of -11.3 to 2.5 mm Hg. Bland-Altman analysis of PCWP-end Exp and LVEDP-end Exp revealed a mean bias of 0.9 mm Hg with 95% limits of agreement of -5.2 to 6.9 mm Hg. If PCWP-digital were used to define LVEDP-end Exp, 14 (27%) of 52 patients would have been misclassified as having PAH rather than PH-HFpEF. Patients with obesity and hypoxia were particularly more likely to be misclassified as PAH instead of PH-HFpEF if PCWP-digital was used to define LVEDP-end Exp (odds ratio 8.1, 95% CI 1.644-40.04, P = .01).

CONCLUSIONS

The common practice of using PCWP-digital instead of PCWP-end Exp results in a significant underestimation of LVEDP-end Exp. In our study, this translated to nearly 30% of patients being misclassified as having PAH rather than PH from HFpEF.

Late gadolinium enhancement cardiovascular magnetic resonance predicts clinical worsening in patients with pulmonary hypertension

BACKGROUND

Late gadolinium enhancement (LGE) occurs at the right ventricular (RV) insertion point (RVIP) in patients with pulmonary hypertension (PH) and has been shown to correlate with cardiovascular magnetic resonance (CMR) derived RV indices. However, the prognostic role of RVIP-LGE and other CMR-derived parameters of RV function are not well established. Our aim was to evaluate the predictive value of contrast-enhanced CMR in patients with PH.

METHODS

RV size, ejection fraction (RVEF), and the presence of RVIP-LGE were determined in 58 patients with PH referred for CMR. All patients underwent right heart catheterization, exercise testing, and N-terminal pro-brain natriuretic peptide (NT-proBNP) evaluation; results of which were included in the final analysis if performed within 4 months of the CMR study. Patients were followed for the primary endpoint of time to clinical worsening (death, decompensated right ventricular heart failure, initiation of prostacyclin, or lung transplantation).

RESULTS

Overall, 40/58 (69%) of patients had RVIP-LGE. Patients with RVIP- LGE had larger right ventricular volume index, lower RVEF, and higher mean pulmonary artery pressure (mPAP), all p < 0.05. During the follow-up period of 10.2 ± 6.3 months, 19 patients reached the primary endpoint. In a univariate analysis, RVIP-LGE was a predictor for adverse outcomes (p = 0.026). In a multivariate analysis, CMR-derived RVEF was an independent predictor of clinical worsening (p = 0.036) along with well-established prognostic parameters such as exercise capacity (p = 0.010) and mPAP (p = 0.001).

CONCLUSIONS

The presence of RVIP-LGE in patients with PH is a marker for more advanced disease and poor prognosis. In addition, this study reveals for the first time that CMR-derived RVEF is an independent non-invasive imaging predictor of adverse outcomes in this patient population.

Plasma von Willebrand factor as a predictor of survival in pulmonary arterial hypertension associated with congenital heart disease

Biomarkers have been identified for pulmonary arterial hypertension, but are less well defined for specific etiologies such as congenital heart disease-associated pulmonary arterial hypertension (CHDPAH). We measured plasma levels of eight microvascular dysfunction markers in CHDPAH, and tested for associations with survival. A cohort of 46 inoperable CHDPAH patients (age 15.0 to 60.2 years, median 33.5 years, female:male 29:17) was prospectively followed for 0.7 to 4.0 years (median 3.6 years). Plasma levels of von Willebrand factor antigen (VWF:Ag), tissue plasminogen activator (t-PA) and its inhibitor (PAI-1), P-selectin, reactive C-protein, tumor necrosis factor alpha, and interleukin-6 and -10 were measured at baseline, and at 30, 90, and 180 days in all subjects. Levels of six of the eight proteins were significantly increased in patients versus controls (13 to 106% increase, P < 0.003). Interleukin-10 level was 2.06 times normal (P = 0.0003; Th2 cytokine response). Increased levels of four proteins (t-PA, PAI-1, P-selectin, and interleukin-6) correlated with disease severity indices (P < 0.05). Seven patients died during follow-up. An average VWF:Ag (mean of four determinations) above the level corresponding to the 95th percentile of controls (139 U/dL) was independently associated with a high risk of death (hazard ratio = 6.56, 95%CI = 1.46 to 29.4, P = 0.014). Thus, in CHDPAH, microvascular dysfunction appears to involve Th2 inflammatory response. Of the biomarkers studied, plasma vWF:Ag was independently associated with survival.