Atrial Arrhythmias in Patients with Pulmonary Hypertension

TOPIC IMPORTANCE

Atrial arrhythmia (AA) are common in patients with pulmonary hypertension (PH) and contribute to morbidity and mortality. Given the growing PH population, it is important to understand the pathophysiology, clinical impact, and management of AA in PH.

REVIEW FINDINGS

AA occurs in PH with a five-year incidence of 10-25%. AA confers a higher morbidity and mortality, and restoration of normal sinus rhythm improves survival and functionality. AA is thought to develop due to structural alterations of the right atrium caused by changes to the right ventricle (RV) due to elevated pulmonary artery pressures. AA can subsequently worsen RV function. Current guidelines do not provide comprehensive recommendations for the management of AA in PH. There is a lack of robust evidence to favor a specific treatment approach. While the role of medical rate or rhythm control, and the use of cardioversion and ablation, can be inferred from other populations, there is a lack of evidence in the PH population. Much remains to be determined regarding the optimal management strategy. We present here our institutional approach and discuss areas for future research.

SUMMARY

This review highlights the epidemiology and pathophysiology of AA in patients with PH, describes the relationship between AA and RV dysfunction, and discusses current management practices. We outline our institutional approach and offer directions for future investigation.

The ALPHA phase 1 study: pulmonary ArteriaL hypertension treated with CardiosPHere-Derived allogeneic stem cells

BACKGROUND

Pulmonary Arterial Hypertension (PAH) is a progressive condition with no cure. Even with pharmacologic advances, survival remains poor. Lung pathology on PAH therapies still shows impressive occlusive arteriolar remodelling and plexiform lesions. Cardiosphere-derived cells (CDCs) are heart-derived progenitor cells exhibiting anti-inflammatory and immunomodulatory effects, are anti -fibrotic, anti-oxidative and anti-apoptotic to potentially impact several aspects of PAH pathobiology. In preclinical trials CDCs reduced right ventricular (RV) systolic pressure, RV hypertrophy, pulmonary arteriolar wall thickness and inflammation.

METHODS

The ALPHA study was a Phase 1a/b study in which CDCs were infused into patients with Idiopathic (I)PAH, Heritable (H) HPAH, PAH-connective tissue disease (CTD) and PAH-human immunodeficiency virus (HIV). The study was IRB approved and DSMB monitored. Phase 1a, was an open label study (n = 6). Phase 1b was a double-blind placebo-controlled study (n = 20) in which half received 100 million CDCs (the maximum feasible dose from manufacturing perspective) and half placebo (PLAC) infusions. Right heart catheterization (RHC) and cardiac MR imaging (cMR) were performed at baseline and at 4 months post infusion. Patients were followed over a year.

FINDINGS

No short-term clinical safety adverse events (AE) were related to the IP, the primary outcome measure. There were no adverse hemodynamic, gas exchange, rhythm or other clinical events following infusion and in the 1st 23 h monitored in hospital. There were no long-term AEs over 12 months noted, including unrelated limited hospitalizations. No immunologic short or long-term AEs were noted. We examined exploratory outcomes across multiple domains to determine encouraging signals to motivate future advanced phase testing. Phase 1a data showed encouraging observations for both 50 and 100 million CDC doses. Several encouraging findings favouring CDCs (n = 16) compared to placebo (n = 10) were noted. On cMR, the RV end diastolic volume (RVEDV) and index (RVEDVI) decreased with CDCs with a rise in the PLAC group. The 6-min walk distance was increased 2 months post infusion in the CDC group compared with PLAC. With PLAC, diffusing capacity (DLCO) decreased at 4 months but was unchanged with CDCs. Serum creatinine decreased with CDCs at 4 months. Encouraging observations favouring CDCs were also noted for RV fractional area change on echo and RV ejection fraction (RVEF) on cMR at 4 months. No differences were observed for mean pulmonary artery pressures or pulmonary vascular resistance. Review of long-term data to 12 months showed continued decline in DLCO for the PLAC cohort at 6 months with no change through 12 months. By contrast, CDC subjects showed an unchanged DLCO over 12-months. For parameters exhibiting early encouraging exploratory findings in CDC subjects, no further improvement was noted in long-term follow up through 12 months.

INTERPRETATION

Intravenous CDCs were safe in both the short and long term in PAH subjects and thus may be safe in larger cohorts, in line with our extensive track record of safety in clinical trials for other conditions. Further, CDCs exhibited encouraging exploratory findings across several domains. Repeat dosing (quarterly, over one year) of intravenous CDCs has been reported to yield highly significant sustained disease-modifying bioactivity in subjects with advanced Duchenne muscular dystrophy. Because only single CDC doses were used here, the findings represent a lower limit estimate of CDC's potential in PAH. Upcoming phase 2 studies would logically use a repeat dosing paradigm.

FUNDING

California Institute for Regenerative Medicine (CIRM). Project Number: CLIN2-09444.

Exercise Stress Echocardiography of the Right Ventricle and Pulmonary Circulation

BACKGROUND

Exercise echocardiography is used for assessment of pulmonary circulation and right ventricular function, but limits of normal and disease-specific changes remain insufficiently established.

OBJECTIVES

The objective of this study was to explore the physiological vs pathologic response of the right ventricle and pulmonary circulation to exercise.

METHODS

A total of 2,228 subjects were enrolled: 375 healthy controls, 40 athletes, 516 patients with cardiovascular risk factors, 17 with pulmonary arterial hypertension, 872 with connective tissue diseases without overt pulmonary hypertension, 113 with left-sided heart disease, 30 with lung disease, and 265 with chronic exposure to high altitude. All subjects underwent resting and exercise echocardiography on a semirecumbent cycle ergometer. All-cause mortality was recorded at follow-up.

RESULTS

The 5th and 95th percentile of the mean pulmonary artery pressure-cardiac output relationships were 0.2 to 3.5 mm Hg.min/L in healthy subjects without cardiovascular risk factors, and were increased in all patient categories and in high altitude residents. The 5th and 95th percentile of the tricuspid annular plane systolic excursion to systolic pulmonary artery pressure ratio at rest were 0.7 to 2.0 mm/mm Hg at rest and 0.5 to 1.5 mm/mm Hg at peak exercise, and were decreased at rest and exercise in all disease categories and in high-altitude residents. An increased all-cause mortality was predicted by a resting tricuspid annular plane systolic excursion to systolic pulmonary artery pressure <0.7 mm/mm Hg and mean pulmonary artery pressure-cardiac output >5 mm Hg.min/L.

CONCLUSIONS

Exercise echocardiography of the pulmonary circulation and the right ventricle discloses prognostically relevant differences between healthy subjects, athletes, high-altitude residents, and patients with various cardio-respiratory conditions. (Right Heart International NETwork During Exercise in Different Clinical Conditions; NCT03041337).

Pathogenesis, clinical features, and phenotypes of pulmonary hypertension associated with interstitial lung disease: A consensus statement from the Pulmonary Vascular Research Institute's Innovative Drug Development Initiative - Group 3 Pulmonary Hypertension

Pulmonary hypertension (PH) is a frequent complication of interstitial lung disease (ILD). Although PH has mostly been described in idiopathic pulmonary fibrosis, it can manifest in association with many other forms of ILD. Associated pathogenetic mechanisms are complex and incompletely understood but there is evidence of disruption of molecular and genetic pathways, with panvascular histopathologic changes, multiple pathophysiologic sequelae, and profound clinical ramifications. While there are some recognized clinical phenotypes such as combined pulmonary fibrosis and emphysema and some possible phenotypes such as connective tissue disease associated with ILD and PH, the identification of further phenotypes of PH in ILD has thus far proven elusive. This statement reviews the current evidence on the pathogenesis, recognized patterns, and useful diagnostic tools to detect phenotypes of PH in ILD. Distinct phenotypes warrant recognition if they are characterized through either a distinct presentation, clinical course, or treatment response. Furthermore, we propose a set of recommendations for future studies that might enable the recognition of new phenotypes.

Outcomes and Prognostic Factors of Pulmonary Hypertension Patients Undergoing Emergent Endotracheal Intubation

Background: Emergent endotracheal intubations (ETI) in pulmonary hypertension (PH) patients are associated with increased mortality. Post-intubation interventions that could increase survivability in this population have not been explored. We evaluate early clinical characteristics and complications following emergent endotracheal intubation and seek predictors of adverse outcomes during this post-intubation period. Methods: Retrospective cohort analysis of adult patients with groups 1 and 3 PH who underwent emergent intubation between 2005-2021 in medical and liver transplant ICUs at a tertiary medical center. PH patients were compared to non-PH patients, matched by Charlson Comorbidity Index. Primary outcomes were 24-h post-intubation and inpatient mortalities. Various 24-h post-intubation secondary outcomes were compared between PH and control cohorts. Results: We identified 48 PH and 110 non-PH patients. Pulmonary hypertension was not associated with increased 24-h mortality (OR 1.32, 95%CI 0.35-4.94, P = .18), but was associated with inpatient mortality (OR 4.03, 95%CI 1.29-12.5, P = .016) after intubation. Within 24 h post-intubation, PH patients experienced more frequent acute kidney injury (43.5% vs. 19.8%, P = .006) and required higher norepinephrine dosing equivalents (6.90 [0.13-10.6] mcg/kg/min, vs. 0.20 [0.10-2.03] mcg/kg/min, P = .037). Additionally, the median P/F ratio (PaO₂/FiO₂) was lower in PH patients (96.3 [58.9-201] vs. 233 [146-346] in non-PH, P = .001). Finally, a post-intubation increase in PaCO₂ was associated with mortality in the PH cohort (post-intubation change in PaCO₂ +5.14 ± 16.1 in non-survivors vs. -18.7 ± 28.0 in survivors, P = .007). Conclusions: Pulmonary hypertension was associated with worse outcomes after emergent endotracheal intubation than similar patients without PH. More importantly, our data suggest that the first 24 hours following intubation in the PH group represent a particularly vulnerable period that may determine long-term outcomes. Early post-intubation interventions may be key to improving survival in this population.

Sex Differences in Outcomes of Percutaneous Pulmonary Artery Thrombectomy in Patients With Pulmonary Embolism

BACKGROUND

The sex differences in use, safety outcomes, and health-care resource use of patients with pulmonary embolism (PE) undergoing percutaneous pulmonary artery thrombectomy are not well characterized.

RESEARCH QUESTION

What are the sex differences in outcomes for patients diagnosed with PE who undergo percutaneous pulmonary artery thrombectomy?

STUDY DESIGN AND METHODS

This retrospective cross-sectional study used national inpatient claims data to identify patients in the United States with a discharge diagnosis of PE who underwent percutaneous thrombectomy between January 2016 and December 2018. We evaluated the demographics, comorbidities, safety outcomes (in-hospital mortality), and health-care resource use (discharge to home, length of stay, and hospital charges) of patients with PE undergoing percutaneous thrombectomy.

RESULTS

Among 1,128,904 patients with a diagnosis of PE between 2016 and 2018, 5,160 patients (0.5%) underwent percutaneous pulmonary artery thrombectomy. When compared with male patients, female patients showed higher procedural bleeding (16.9% vs 11.2%; P < .05), required more blood transfusions (11.9% vs 5.7%; P < .05), and experienced more vascular complications (5.0% vs 1.5%; P < .05). Women experienced higher in-hospital mortality (16.9% vs 9.3%; adjusted OR, 1.9; 95% CI, 1.2-3.0; P = .003) when compared with men. Although length of stay and hospital charges were similar to those of men, women were less likely to be discharged home after surviving hospitalization (47.9% vs 60.3%; adjusted OR, 0.7; 95% CI, 0.50-0.99; P = .04).

INTERPRETATION

In this large nationwide cohort, women with PE who underwent percutaneous thrombectomy showed higher morbidity and in-hospital mortality compared with men.

Expert consensus on the management of systemic sclerosis-associated interstitial lung disease

BACKGROUND

Systemic sclerosis (SSc) is a rare, complex, connective tissue disorder. Interstitial lung disease (ILD) is common in SSc, occurring in 35-52% of patients and accounting for 20-40% of mortality. Evolution of therapeutic options has resulted in a lack of consensus on how to manage this condition. This Delphi study was initiated to develop consensus recommendations based on expert physician insights regarding screening, progression, treatment criteria, monitoring of response, and the role of recent therapeutic advances with antifibrotics and immunosuppressants in patients with SSc-ILD.

METHODS

A modified Delphi process was completed by pulmonologists (n = 13) and rheumatologists (n = 12) with expertise in the management of patients with SSc-ILD. Panelists rated their agreement with each statement on a Likert scale from - 5 (complete disagreement) to + 5 (complete agreement). Consensus was predefined as a mean Likert scale score of ≤  - 2.5 or ≥  + 2.5 with a standard deviation not crossing zero.

RESULTS

Panelists recommended that all patients with SSc be screened for ILD by chest auscultation, spirometry with diffusing capacity of the lungs for carbon monoxide, high-resolution computed tomography (HRCT), and/or autoantibody testing. Treatment decisions were influenced by baseline and changes in pulmonary function tests, extent of ILD on HRCT, duration and degree of dyspnea, presence of pulmonary hypertension, and potential contribution of reflux. Treatment success was defined as stabilization or improvement of signs or symptoms of ILD and functional status. Mycophenolate mofetil was identified as the initial treatment of choice. Experts considered nintedanib a therapeutic option in patients with progressive fibrotic ILD despite immunosuppressive therapy or patients contraindicated/unable to tolerate immunotherapy. Concomitant use of nintedanib with MMF/cyclophosphamide can be considered in patients with advanced disease at initial presentation, aggressive ILD, or significant disease progression. Although limited consensus was achieved on the use of tocilizumab, the experts considered it a therapeutic option for patients with early SSc and ILD with elevated acute-phase reactants.

CONCLUSIONS

This modified Delphi study generated consensus recommendations for management of patients with SSc-ILD in a real-world setting. Findings from this study provide a management algorithm that will be helpful for treating patients with SSc-ILD and addresses a significant unmet need.

Methamphetamine-associated pulmonary arterial hypertension

PURPOSE OF REVIEW

Methamphetamine use is increasing in popularity globally, and chronic users suffer from various drug toxicities, including the development of pulmonary arterial hypertension. Although it was previously thought to be a possible cause of pulmonary arterial hypertension, as of the sixth World Symposium on Pulmonary Hypertension, methamphetamine use is now recognized as a definite cause of pulmonary arterial hypertension. This review will discuss the history of methamphetamine use, the link between methamphetamine use and pulmonary arterial hypertension, and the clinical characteristics of patients with pulmonary hypertension from methamphetamine use.

RECENT FINDINGS

The mechanism by which methamphetamine abuse leads to pulmonary hypertension is unclear. However, recent studies have suggested that reduced expression of carboxylesterase 1 may be implicated due to maladaptation to the environmental injury of methamphetamine abuse. Based on the report of two recent cohort studies, patients with methamphetamine-associated pulmonary arterial hypertension have a worse functional class, less favorable hemodynamics, impaired health-related quality of life, increased health-care utilization, and attenuated survival, as compared to those with idiopathic pulmonary arterial hypertension.

SUMMARY

Future studies are needed to better understand the mechanism by which methamphetamine use leads to pulmonary arterial hypertension. Methamphetamine-associated pulmonary arterial hypertension likely represents a more advanced disease state than idiopathic pulmonary arterial hypertension, however, it is treated less aggressively in clinical practice.

CLINICAL SIGNIFICANCE OF PULMONARY HYPERTENSION IN INTERSTITIAL LUNG DISEASE A Consensus Statement from The Pulmonary Vascular Research Institute's Innovative Drug Development Initiative ‐ Group 3 Pulmonary Hypertension

Pulmonary hypertension (PH) has been linked to worse outcomes in chronic lung diseases. The presence of PH in the setting of underlying Interstitial Lung Disease (ILD) is strongly associated with decreased exercise and functional capacity, an increased risk of hospitalizations and death. Examining the scope of this issue and its impact on patients is the first step in trying to define a roadmap to facilitate and encourage future research in this area. The aim of our working group is to strengthen the communities understanding of PH due to lung diseases and to improve the care and quality of life of affected patients. This introductory statement provides a broad overview and lays the foundation for further in‐depth papers on specific topics pertaining to PH‐ILD.

Screening Strategies for Pulmonary Hypertension in Patients With Interstitial Lung Disease: A Multidisciplinary Delphi Study

BACKGROUND

Pulmonary hypertension (PH) is a common complication of interstitial lung disease (ILD) and is associated with worse outcomes and increased mortality. Evaluation of PH is recommended in lung transplant candidates, but there are currently no standardized screening approaches. Trials have identified therapies that are effective in this setting, providing another rationale to routinely screen patients with ILD for PH.

RESEARCH QUESTION

What screening strategies for identifying PH in patients with ILD are supported by expert consensus?

STUDY DESIGN AND METHODS

The study convened a panel of 16 pulmonologists with expertise in PH and ILD, and used a modified Delphi consensus process with three surveys to identify PH screening strategies. Survey 1 consisted primarily of open-ended questions. Surveys 2 and 3 were developed from responses to survey 1 and contained statements about PH screening that panelists rated from -5 (strongly disagree) to 5 (strongly agree).

RESULTS

Panelists reached consensus on several triggers for suspicion of PH including the following: symptoms, clinical signs, findings on chest CT scan or other imaging, abnormalities in pulse oximetry, elevations in brain natriuretic peptide (BNP) or N-terminal pro-brain natriuretic peptide (NT-proBNP), and unexplained worsening in pulmonary function tests or 6-min walk distance. Echocardiography and BNP/NT-proBNP were identified as screening tools for PH. Right heart catheterization was deemed essential for confirming PH.

INTERPRETATION

Many patients with ILD may benefit from early evaluation of PH now that an approved therapy is available. Protocols to evaluate patients with ILD often overlap with evaluations for pulmonary hypertension-interstitial lung disease and can be used to assess the risk of PH. Because standardized approaches are lacking, this consensus statement is intended to aid physicians in the identification of patients with ILD and possible PH, and provide guidance for timely right heart catheterization.

Quantitative Image Analysis at Chronic Lung Allograft Dysfunction Onset Predicts Mortality

BACKGROUND

Chronic lung allograft dysfunction (CLAD) phenotype determines prognosis and may have therapeutic implications. Despite the clarity achieved by recent consensus statement definitions, their reliance on radiologic interpretation introduces subjectivity. The Center for Computer Vision and Imaging Biomarkers at the University of California, Los Angeles (UCLA) has established protocols for chest high-resolution computed tomography (HRCT)-based computer-aided quantification of both interstitial disease and air-trapping. We applied quantitative image analysis (QIA) at CLAD onset to demonstrate radiographic phenotypes with clinical implications.

METHODS

We studied 47 first bilateral lung transplant recipients at UCLA with chest HRCT performed within 90 d of CLAD onset and 47 no-CLAD control HRCTs. QIA determined the proportion of lung volume affected by interstitial disease and air-trapping in total lung capacity and residual volume images, respectively. We compared QIA scores between no-CLAD and CLAD, and between phenotypes. We also assigned radiographic phenotypes based solely on QIA, and compared their survival outcomes.

RESULTS

CLAD onset HRCTs had more lung affected by the interstitial disease (P = 0.003) than no-CLAD controls. Bronchiolitis obliterans syndrome (BOS) cases had lower scores for interstitial disease as compared with probable restrictive allograft syndrome (RAS) (P < 0.0001) and mixed CLAD (P = 0.02) phenotypes. BOS cases had more air-trapping than probable RAS (P < 0.0001). Among phenotypes assigned by QIA, the relative risk of death was greatest for mixed (relative risk [RR] 11.81), followed by RAS (RR 6.27) and BOS (RR 3.15).

CONCLUSIONS

Chest HRCT QIA at CLAD onset appears promising as a method for precise determination of CLAD phenotypes with survival implications.

Diagnosis and Treatment of Pulmonary Sarcoidosis: A Review

IMPORTANCE

Sarcoidosis is an inflammatory granulomatous disease of unknown cause that affects an estimated 2 to 160 people per 100 000 worldwide and can involve virtually any organ. Approximately 10% to 30% of patients with sarcoidosis develop progressive pulmonary disease.

OBSERVATION

Among patients with pulmonary sarcoidosis, the rate of spontaneous remission without serious sequelae ranges from 10% to 82%. However, lung disease progression occurs in more than 10% of patients and can result in fibrocystic architectural distortion of the lung, which is associated with a mortality rate of 12% to 18% within 5 years. Overall, the mortality rate for sarcoidosis is approximately 7% within a 5-year follow-up period. Worldwide, more than 60% of deaths from sarcoidosis are due to pulmonary involvement; however, more than 70% of deaths from sarcoidosis are due to cardiac involvement in Japan. Up to 70% of patients with advanced pulmonary sarcoidosis develop precapillary pulmonary hypertension, which is associated with a 5-year mortality rate of approximately 40%. Patients with sarcoidosis and precapillary pulmonary hypertension should be treated with therapies such as phosphodiesterase inhibitors and prostacyclin analogues. Although optimal doses of oral glucocorticoids for pulmonary sarcoidosis are unknown, oral prednisone typically starting at a dose of 20 mg/d to 40 mg/d for 2 to 6 weeks is recommended for patients who are symptomatic (cough, dyspnea, and chest pain) and have parenchymal infiltrates and abnormal pulmonary function test results. Oral glucocorticoids can be tapered over 6 to 18 months if symptoms, pulmonary function test results, and radiographs improve. Prolonged use of oral glucocorticoids may be required to control symptoms and stabilize disease. Patients without adequate improvement while receiving a dose of prednisone of 10 mg/d or greater or those with adverse effects due to glucocorticoids may be prescribed immunosuppressive agents, such as methotrexate, azathioprine, or an anti-tumor necrosis factor medication, either alone or with glucocorticoids combined with appropriate microbial prophylaxis for Pneumocystis jiroveci and herpes zoster. Effective treatments are not available for advanced fibrocystic pulmonary disease.

CONCLUSIONS AND RELEVANCE

Sarcoidosis has a mortality rate of approximately 7% within a 5-year follow-up period. More than 10% of patients with pulmonary sarcoidosis develop progressive disease and more than 60% of deaths are due to advanced pulmonary sarcoidosis. Oral glucocorticoids with or without another immunosuppressive agent are the first-line therapy for symptomatic patients with abnormal pulmonary function test results and lung infiltrates. Patients with sarcoidosis and precapillary pulmonary hypertension should be treated with therapies such as phosphodiesterase inhibitors and prostacyclin analogues.

The allograft injury marker CXCL9 determines prognosis of anti-HLA antibodies after lung transplantation

Despite the common detection of non-donor specific anti-HLA antibodies (non-DSAs) after lung transplantation, their clinical significance remains unclear. In this retrospective single-center cohort study of 325 lung transplant recipients, we evaluated the association between donor-specific HLA antibodies (DSAs) and non-DSAs with subsequent CLAD development. DSAs were detected in 30% of recipients and were associated with increased CLAD risk, with higher HRs for both de novo and high MFI (>5000) DSAs. Non-DSAs were detected in 56% of recipients, and 85% of DSA positive tests had concurrent non-DSAs. In general, non-DSAs did not increase CLAD risk in multivariable models accounting for DSAs. However, non-DSAs in conjunction with high BAL CXCL9 levels were associated with increased CLAD risk. Multivariable proportional hazards models demonstrate the importance of the HLA antibody-CXCL9 interaction: CLAD risk increases when HLA antibodies (both DSAs and non-DSAs) are detected in conjunction with high CXCL9. Conversely, CLAD risk is not increased when HLA antibodies are detected with low CXCL9. This study supports the potential utility of BAL CXCL9 measurement as a biomarker to risk stratify HLA antibodies for future CLAD. The ability to discriminate between high versus low-risk HLA antibodies may improve management by allowing for guided treatment decisions.

Venoarterial Versus Venovenous Extracorporeal Membrane Oxygenation as Bridge to Lung Transplantation

BACKGROUND

Veno-venous (VV) extracorporeal membrane oxygenation (ECMO) has been used as a bridge to lung transplantation with acceptable outcomes. We hypothesized that VA ECMO, as part of a multidisciplinary ECMO program, yields similar outcomes as VV ECMO as a bridge in lung transplantation.

METHODS

Records of all patients who had undergone ECMO with the intention to bridge to lung transplantation at University of California Los Angeles from January 1, 2012 to March 31, 2020 were reviewed. Baseline characteristics, in-hospital outcomes, long-term survival, and freedom from bronchiolitis obliterans syndrome (BOS) were assessed.

RESULTS

During this interval, 58 patients were placed on ECMO with the intention to bridge to lung transplantation: 27 on VV ECMO, and 31 on VA ECMO with a median duration of 7 and 17 days of support, respectively(p=0.01). Successful bridge to lung transplantation occurred in 21(78%) VV and 26(84%) VA patients. Incidence of primary graft dysfunction III(PGD III) at 72 hours in the VV and the VA cohorts were 0% and 4%, respectively(p=0.99). In-hospital and 90-day survival of the VV and VA groups were 100% and 96%, respectively(p=0.99). Three-year survival of the two groups were not significantly different from a contemporary cohort of lung transplant recipients not bridged with ECMO.

CONCLUSIONS

VA and VV ECMO can both be used as a bridge to lung transplantation with high success, with short and medium-term survival similar to non-bridged lung transplant recipients. Both modes should be considered effective at bridging select candidates to lung transplantation.

Update on Medical Management of Pulmonary Arterial Hypertension

Pulmonary arterial hypertension is a rare disease characterized by pulmonary microvasculature remodeling leading to right ventricular failure and death. Medical management of pulmonary hypertension has grown increasingly complex as more therapeutic agents have been developed. Evolving treatment strategies leveraging the endothelin, nitric oxide, and prostacyclin pathways lead to improved exercise capacity and outcomes in patients; however, significant opportunities for advancement remain.

Right Heart Pulmonary Circulation Unit Involvement in Left-Sided Heart Failure: Diagnostic, Prognostic, and Therapeutic Implications

Although long neglected, the right heart (RH) is now widely accepted as a pivotal player in heart failure (HF) either with reduced or preserved ejection fraction. The chronic overload of the pulmonary microcirculation results in an initial phase characterized by right ventricular (RV) hypertrophy, right atrial dilation, and diastolic dysfunction. This progresses to overt RH failure when RV dilation and systolic dysfunction lead to RV-pulmonary arterial (RV-PA) uncoupling with low RV output. In the context of its established relevance to progression of HF, clinicians should consider assessment of the RH with information from clinical assessment, biomarkers, and imaging. Notably, no single parameter can predict prognosis alone in HF. Assessments simultaneously should encompass RV systolic function, pulmonary pressures, an estimation of RV-PA coupling, and RH morphologic features. Despite a large volume of evidence indicating the relevance of RH function to the clinical syndrome of HF, evidence-based management strategies are lacking. Targeting RH dysfunction in HF should be an objective of future investigations, being an unmet need in the current management of HF.

Extrapulmonary sarcoidosis with a focus on cardiac, nervous system, and ocular involvement

Sarcoidosis is a poorly understood granulomatous disease that involves the lungs and/or intrathoracic lymph nodes in more than 90% of cases. Although pulmonary sarcoidosis is the leading cause of mortality in this disease, this review focuses on three sites of extrapulmonary involvement (heart, nervous system, and eyes), since involvement of any of these sites can be catastrophic, leading to death, debilitation, or blindness. Patients with cardiac, ocular and neurosarcoidosis necessitate a multidisciplinary approach with careful and long-term follow-up. Prompt diagnosis with imaging and/or biopsy and treatment is required to avoid irreversible damage. Corticosteroids are the mainstay of therapy and are often associated with rapid and durable remissions. Immunosuppressive or biologic agents are reserved for patients failing or experiencing side effects from steroids. Managing sarcoidosis requires vigilance, judgement, and awareness of the vagaries of this fascinating disease.

824 Case Series on the Use of Volume Assured Pressure Support in Patients with Chronic Pulmonary Disease and Progressive Hypercapnia

Introduction

Chronic hypercapnia results from destruction of lung parenchyma which occurs in chronic lung diseases including interstitial lung disease (ILD), bronchiectasis, and chronic lung transplant rejection. Many patients with these diseases will experience progressive respiratory failure eventually requiring consideration of transplantation or re-transplantation. Due to physiologic changes in sleep including reduction in tidal volume, worsening air tapping, and REM atonia, hypoventilation can be exacerbated during the sleeping hours. We present four patients who were prescribed nocturnal Volume Assured Pressure Support VAPS for their progressive hypercapnia.

Report of case(s)

Subject 1 is a 72 year old female with severe bronchiectasis and restrictive lung disease due to TB pneumonia at a young age. Subject 2 is a 45 year old male with history of pulmonary cavitation due to extensive TB disease when he was younger. Subject 3 is a 45-year-old woman with rheumatoid arthritis related ILD with associated pulmonary arterial hypertension. Subject 4 is a 74 year old patient with a bilateral lung transplant for IPF complicated by bronchiolitis obliterans syndrome who presented with progressive dyspnea and hypercapnia. Despite optimal therapy, all of these patients were admitted for hypercapnic and hypoxemic respiratory failure requiring treatment with BPAP then transitioned to nocturnal VAPS on discharge. For all patients, dyspnea and pCO2 improved as outpatients although all patients did eventually experience an exacerbation of their lung disease requiring repeat admission.

Conclusion

Due to the physiologic changes that occur with sleep, patients with severe lung disease may experience worsening CO2 retention while sleeping. There is little data assessing the use of chronic nocturnal non-invasive ventilation (NIV) to treat the hypercapnia of chronic lung diseases other than chronic obstructive pulmonary disease, extra-thoracic restriction, and neuromuscular disease. In this case series, nocturnal VAPS stabilized and/or reduced pCO2 in patients with pulmonary parenchymal disease of various etiologies. Additional studies are needed to assess long term effects of VAPS in these patients, including exacerbations, symptoms, and overall mortality.

Support (if any):

Feasibility of semi-recumbent bicycle exercise Doppler echocardiography for the evaluation of the right heart and pulmonary circulation unit in different clinical conditions: the RIGHT heart international NETwork (RIGHT-NET)

Exercise Doppler echocardiography (EDE) is a well-validated tool in ischemic and valvular heart diseases. However, its use in the assessment of the right heart and pulmonary circulation unit (RH-PCU) is limited. The aim of this study is to assess the semi-recumbent bicycle EDE feasibility for the evaluation of RH-PCU in a large multi-center population, from healthy individuals and elite athletes to patients with overt or at risk of developing pulmonary hypertension (PH). From January 2019 to July 2019, 954 subjects [mean age 54.2 ± 16.4 years, range 16-96, 430 women] underwent standardized semi-recumbent bicycle EDE with an incremental workload of 25 watts every 2 min, were prospectively enrolled among 7 centers participating to the RIGHT Heart International NETwork (RIGHT-NET). EDE parameters of right heart structure, function and pressures were obtained according to current recommendations. Right ventricular (RV) function at peak exercise was feasible in 903/940 (96%) by tricuspid annular plane systolic excursion (TAPSE), 667/751 (89%) by tissue Doppler-derived tricuspid lateral annular systolic velocity (S') and 445/672 (66.2%) by right ventricular fractional area change (RVFAC). RV-right atrial pressure gradient [RV-RA gradient = 4 × tricuspid regurgitation velocity² (TRV)] was feasible in 894/954 patients (93.7%) at rest and in 816/954 (85.5%) at peak exercise. The feasibility rate in estimating pulmonary artery pressure improved to more than 95%, if both TRV and/or right ventricular outflow tract acceleration time (RVOT AcT) were considered. In high specialized echocardiography laboratories semi-recumbent bicycle EDE is a feasible tool for the assessment of the RH-PCU pressure and function.

Single-Cell Study of Two Rat Models of Pulmonary Arterial Hypertension Reveals Connections to Human Pathobiology and Drug Repositioning

Rationale: The cellular and molecular landscape and translational value of commonly used models of pulmonary arterial hypertension (PAH) are poorly understood. Single-cell transcriptomics can enhance molecular understanding of preclinical models and facilitate their rational use and interpretation.Objectives: To determine and prioritize dysregulated genes, pathways, and cell types in lungs of PAH rat models to assess relevance to human PAH and identify drug repositioning candidates.Methods: Single-cell RNA sequencing was performed on the lungs of monocrotaline (MCT), Sugen-hypoxia (SuHx), and control rats to identify altered genes and cell types, followed by validation using flow-sorted cells, RNA in situ hybridization, and immunofluorescence. Relevance to human PAH was assessed by histology of lungs from patients and via integration with human PAH genetic loci and known disease genes. Candidate drugs were predicted using Connectivity Map.Measurements and Main Results: Distinct changes in genes and pathways in numerous cell types were identified in SuHx and MCT lungs. Widespread upregulation of NF-κB signaling and downregulation of IFN signaling was observed across cell types. SuHx nonclassical monocytes and MCT conventional dendritic cells showed particularly strong NF-κB pathway activation. Genes altered in SuHx nonclassical monocytes were significantly enriched for PAH-associated genes and genetic variants, and candidate drugs predicted to reverse the changes were identified. An open-access online platform was developed to share single-cell data and drug candidates (http://mergeomics.research.idre.ucla.edu/PVDSingleCell/).Conclusions: Our study revealed the distinct and shared dysregulation of genes and pathways in two commonly used PAH models for the first time at single-cell resolution and demonstrated their relevance to human PAH and utility for drug repositioning.

Significance of autoimmune disease in severe pulmonary hypertension complicating extensive pulmonary fibrosis: a prospective cohort study

The association of autoimmune disease (AI) with transplant-free survival in the setting of severe Group 3 pulmonary hypertension and extensive pulmonary fibrosis remains unclear. We report cases of severe pulmonary hypertension (mean pulmonary artery pressure ≥35 mmHg and right ventricular dysfunction) and extensive pulmonary fibrosis after pulmonary arterial hypertension-specific therapy. We used multivariate regression to determine the clinical variables associated with transplant-free survival. Of 286 screened patients, 55 demonstrated severe pulmonary hypertension and extensive pulmonary fibrosis and were treated with parenteral prostacyclin therapy. The (+)AI subgroup (n = 34), when compared to the (-)AI subgroup (n = 21), was more likely to be female (77% versus 19%) and younger (58.7 ± 12.1 versus 66.0 ± 10.7 years), and revealed lower forced vital capacity (absolute) (1.9 ± 0.7 versus 2.9 ± 1.1 L), higher DLCO (% predicted) (31.1 ± 15.2 versus 23.2 ± 8.0), and increased unadjusted transplant-free survival (1 year (84.6 ± 6.3% versus 45 ± 11.1%)), 3 years (71 ± 8.2% versus 28.6 ± 11.9%), and 5 years (47.6 ± 9.6% versus 6.4 ± 8.2%); (p = 0.01)). Transplant-free survival was unchanged after adjusting for age and gender. The pulmonary hemodynamic profiles improved after parenteral prostacyclin therapy, independent of AI status. The baseline variables associated with mortality included age at pulmonary hypertension diagnosis (heart rate (HR) 1.23 (confidence interval (CI) 1.03-1.47); p = 0.02) and presence of AI (HR 0.26 (confidence interval (CI) 0.10-0.70); p < 0.01). Gas exchange was not adversely affected by parenteral prostacyclin therapy. In the setting of severe Group 3 pulmonary hypertension and extensive pulmonary fibrosis treated with pulmonary arterial hypertension-specific therapy, AI is independently associated with increased transplant-free survival. Pulmonary hypertension/pulmonary fibrosis associated with AI should be considered in future clinical trials of pulmonary arterial hypertension-specific therapy in Group 3 pulmonary hypertension.

Long-Term Outcomes in Patients With Connective Tissue Disease-Associated Pulmonary Arterial Hypertension in the Modern Treatment Era: Meta-Analyses of Randomized, Controlled Trials and Observational Registries

Objective

Data on the magnitude of benefit of modern therapies for pulmonary arterial hypertension (PAH) in connective tissue disease (CTD)–associated PAH are limited. In this study, we performed meta‐analyses of randomized, controlled trials (RCTs) and registries to quantify the benefit of these modern therapies in patients with CTD‐PAH.

Methods

The PubMed and Embase databases were searched for articles reporting data from RCTs or registries published between January 1, 2000 and November 25, 2019. Eligibility criteria included multicenter studies with ≥30 CTD‐PAH patients. For an RCT to be included, the trial had to evaluate an approved PAH therapy, and long‐term risks of clinical morbidity and mortality or 6‐minute walk distance had to be reported. For a registry to be included, survival rates had to be reported. Random‐effects models were used to pool the data.

Results

Eleven RCTs (total of 4,329 patients; 1,267 with CTD‐PAH) and 19 registries (total of 9,739 patients; 4,008 with CTD‐PAH) were included. Investigational therapy resulted in a 36% reduction in the risk of clinical morbidity/mortality events both in the overall PAH population (hazard ratio [HR] 0.64, 95% confidence interval [95% CI] 0.54, 0.75; P < 0.001) and in CTD‐PAH patients (HR 0.64, 95% CI 0.51, 0.81; P < 0.001) as compared to control subjects. The survival rate was lower in CTD‐PAH patients compared to all PAH patients (survival rate 62%, 95% CI 57, 67% versus 72%, 95% CI 69, 75% at 3 years). The survival rate in CTD‐PAH patients treated primarily after 2010 was higher than that in CTD‐PAH patients treated before 2010 (survival rate 73%, 95% CI 62, 81% versus 65%, 95% CI 59, 71% at 3 years).

Conclusion

Modern therapy provides a similar reduction in morbidity/mortality risk in patients with CTD‐PAH when compared to the PAH population overall. Risk of death is higher in CTD‐PAH patients than in those with PAH overall, but survival has improved in the last 10 years, which may be related to increased screening and/or new treatment approaches. Early detection of PAH in patients with CTD and up‐front intensive treatment are warranted.

Brain Structural Changes in Patients with Pulmonary Arterial Hypertension

BACKGROUND AND PURPOSE

Patients with pulmonary arterial hypertension (PAH) frequently present with anxiety, depression, autonomic, and cognitive deterioration, which may indicate brain changes in regions that control these functions. However, the precise regional brain-injury in sites that regulate cognitive, autonomic, and mood functions in PAH remains unclear. We examined the shifts in regional gray matter (GM) volume, using high-resolution T1-weighted images, and brain tissue alterations, using T2-relaxometry procedures, in PAH compared to healthy subjects.

METHODS

We collected two high-resolution T1-weighted series, and proton-density and T2-weighted images using a 3.0-Tesla magnetic resonance imaging scanner from 9 PAH and 19 healthy subjects. Both high-resolution T1-weighted images were realigned and averaged, partitioned to GM tissue type, normalized to a common space, and smoothed. Using proton-density and T2-weighted images, T2-relaxation maps were calculated, normalized to a common space, and smoothed. Whole-brain GM volume and T2-relaxation maps were compared between PAH and controls using analysis of covariance (covariates, age, sex, and total-brain-volume; false discover rate corrections).

RESULTS

Significantly decreased GM volumes, indicating tissue injury, emerged in multiple brain regions, including the hippocampus, insula, cerebellum, parahippocampus, temporal, frontal, and occipital gyri, cingulate, amygdala, and thalamus. Higher T2-relaxation values, suggesting tissue damage, appeared in the cerebellum, hippocampus, parahippocampus, frontal, lingual, and temporal and occipital gyri, and cingulate areas in PAH compared to healthy subjects.

CONCLUSIONS

PAH patients showed significant GM injury and brain tissue changes in sites that regulate cognition, autonomic, and mood functions. These findings indicate a brain structural basis for functional deficits in PAH patients.

A multicentric quality-control study of exercise Doppler echocardiography of the right heart and the pulmonary circulation. The RIGHT Heart International NETwork (RIGHT-NET)

Purpose

This study was a quality-control study of resting and exercise Doppler echocardiography (EDE) variables measured by 19 echocardiography laboratories with proven experience participating in the RIGHT Heart International NETwork.

Methods

All participating investigators reported the requested variables from ten randomly selected exercise stress tests. Intraclass correlation coefficients (ICC) were calculated to evaluate the inter-observer agreement with the core laboratory. Inter-observer variability of resting and peak exercise tricuspid regurgitation velocity (TRV), right ventricular outflow tract acceleration time (RVOT Act), tricuspid annular plane systolic excursion (TAPSE), tissue Doppler tricuspid lateral annular systolic velocity (S’), right ventricular fractional area change (RV FAC), left ventricular outflow tract velocity time integral (LVOT VTI), mitral inflow pulsed wave Doppler velocity (E), diastolic mitral annular velocity by TDI (e’) and left ventricular ejection fraction (LVEF) were measured.

Results

The accuracy of 19 investigators for all variables ranged from 99.7 to 100%. ICC was > 0.90 for all observers. Inter-observer variability for resting and exercise variables was for TRV = 3.8 to 2.4%, E = 5.7 to 8.3%, e’ = 6 to 6.5%, RVOT Act = 9.7 to 12, LVOT VTI = 7.4 to 9.6%, S’ = 2.9 to 2.9% and TAPSE = 5.3 to 8%. Moderate inter-observer variability was found for resting and peak exercise RV FAC (15 to 16%). LVEF revealed lower resting and peak exercise variability of 7.6 and 9%.

Conclusions

When performed in expert centers EDE is a reproducible tool for the assessment of the right heart and the pulmonary circulation.

Left main coronary artery compression in pulmonary hypertension

Extrinsic compression of the left main coronary artery (LMCA) by a dilated pulmonary artery (PA) in the setting of pulmonary arterial hypertension (PAH) is an increasingly recognized disease entity. LMCA compression has been associated with angina, arrhythmia, heart failure, and sudden cardiac death in patients with PAH. Recent studies suggest that at least 6% of patients with PAH have significant LMCA compression. Screening for LMCA compression can be achieved with computed coronary tomography angiography, with a particular emphasis on assessment of PA size and any associated downward displacement and reduced takeoff angle of the LMCA. Indeed, evidence of a dilated PA (>40 mm), a reduced LMCA takeoff angle (<60°), and/or LMCA stenosis on CCTA imaging should prompt further diagnostic evaluation. Coronary angiography in conjunction with intravascular imaging has proven effective in diagnosing LMCA compression and guiding subsequent treatment. While optimal medical therapy and surgical correction remain in the clinician's arsenal, percutaneous coronary intervention has emerged as an effective treatment for LMCA compression. Given the prevalence of LMCA compression, its associated morbidity, and mortality, and the wide array of successful treatment strategies, maintaining a high degree of suspicion for this condition, and understanding the potential treatment strategies is critical.

Outcomes associated with modern treatment paradigms in connective tissue disease (CTD)-associated pulmonary arterial hypertension (PAH): a meta-analysis of randomized controlled trials (RCTs)

Background

CTD-PAH has historically represented a PAH subtype with poor prognosis. New therapies, as well as combination therapy approaches targeting multiple pathways have been approved for PAH based on RCTs. CTD-PAH patients comprise a subgroup of the RCT populations and efficacy analyses are based on subgroup analyses which can be less reliable than the overall analysis. We conducted a meta-analysis of RCTs of approved PAH therapies to evaluate outcomes of patients with CTD-PAH.

Purpose

To use meta-analysis to determine response to treatment in patients with CTD-PAH.

Methods

The PubMed and EMBASE databases were searched for English-only articles published between January 1, 2000 and November 25, 2019. Inclusion criteria were multicenter RCTs that enrolled adults with WHO group 1 pulmonary hypertension (PAH); enrollment in 2000 or later; long-term clinical morbidity and/or mortality event or 6-minute walk distance (6MWD) as an efficacy endpoint reported for ≥30 patients with CTD-PAH; and evaluation of a US Food and Drug Administration-approved PAH therapy. The primary outcomes were treatment effect as measured by the study time to first morbidity or morality event and change in 6MWD from baseline to between 3–6 months, per the data provided in each article. Results from individual studies were combined using a random-effects model for overall study population (PAH patients) and the subgroup of CTD-PAH patients.

Results

Ten RCTs (N=4329 PAH patients; n=1263 (29%) with CTD-PAH) met inclusion criteria and were included in the meta-analysis. At baseline, PAH patients had a mean age of 50 years, approximately 78% were female, and approximately 58% had functional class III or IV disease. These characteristics were balanced between treatment and control groups. Baseline 6MWD was 356 m for the overall population and 337 m for patients with CTD-PAH. Five RCTs (N=3172; n=941 with CTD-PAH [30%]) reported hazard ratios (HRs) for time to a morbidity or mortality event by drug treatment and PAH etiology: overall population HR=0.63 (95% confidence interval [CI], 0.56–0.72; P&lt;0.001); CTD-PAH population HR=0.64 (95% CI, 0.51–0.80; P&lt;0.001) (Figure). Nine RCTs reported mean change with drug treatment from baseline to 3 to 6 months in 6MWD for PAH and CTD patients: 33.9 m (95% CI, 21.9–45.9; P&lt;0.001) in the overall population; 20.2 m (95% CI, 10.8–29.7; P&lt;0.001) in CTD-PAH patients.

Conclusions

The improvement in 6MWD in patients with CTD-PAH is smaller than in those with other types of PAH, perhaps reflecting comorbidities and CTD-induced mobility constraints, independent of their cardiopulmonary capacity. Data from long term clinical morbidity/mortality endpoint studies in this large group of patients with CTD-PAH demonstrate that these patients derive significant benefit from currently available PAH therapies which, in many patients, comprised the addition of a drug targeting a second or third pathway involved in the pathophysiology of PAH.

Treatment effect on morbidity/mortality

Funding Acknowledgement

Type of funding source: Private company. Main funding source(s): Actelion Pharmaceuticals US, Inc.

Occult Colonic Perforation in a Patient With Coronavirus Disease 2019 After Interleukin-6 Receptor Antagonist Therapy

Background

Interleukin-6 blockade (IL-6) has become a focus of therapeutic investigation for the coronavirus disease 2019 (COVID-19).

Methods

We report a case of a 34-year-old with COVID-19 pneumonia receiving an IL-6 receptor antagonist (IL-6Ra) who developed spontaneous colonic perforation. This perforation occurred despite a benign abdominal exam and in the absence of other known risk factors associated with colonic perforation.

Results

Examination of the colon by electron microscopy revealed numerous intact severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virions abutting the microvilli of the colonic mucosa. Multiplex immunofluorescent staining revealed the presence of the SARS-CoV-2 spike protein on the brush borders of colonic enterocytes that expressed angiotensin-converting enzyme 2. However, no viral particles were observed within the enterocytes to suggest direct viral injury as the cause of colonic perforation.

Conclusions

These data and absence of known risk factors for spontaneous colonic perforation implicate IL-6Ra therapy as the potential mediator of colonic injury in this case. Furthermore, this report provides the first in situ visual evidence of the virus in the colon of a patient presenting with colonic perforation adding to growing evidence that intact infectious virus can be present in the stool.

Weight loss for critical care patient to improve lung transplantation candidacy: A case report

A 47-year-old male with morbid obesity and progressive pulmonary fibrosis was admitted to the intensive care unit (ICU) with worsening hypoxia and nocturnal ventilator dependence. Due to a significant oxygen requirement, the patient could only safely remain in an acute care setting. Unfortunately, he was not eligible for lung transplantation due to having obesity, a relative contraindication to lung transplantation due to potential for post transplantation complications and increased mortality. Therefore, we treated the patient with a modified very low calorie diet (MVLCD) to achieve weight loss. He had successful, sustained weight loss over a period of seven weeks and reached a target weight that made him eligible for transplantation. He subsequently underwent successful bilateral lung transplantation. The patient had improved metabolic parameters and no side effects attributable to the reduced calorie diet. This report shows that in patients with end stage lung disease and a poor prognosis without transplantation, inpatient weight loss is safe and may allow for potentially lifesaving lung transplantation.

Radiographic and Histopathologic Features in Sarcoidosis: A Pictorial Display

Sarcoidosis is a multisystemic granulomatous disorder that can affect virtually any organ. However, pulmonary and thoracic lymph node involvement predominates; abnormalities on chest radiographs are present in 80 to 90% of patients with sarcoidosis. High-resolution computed tomographic (HRCT) scans are superior to chest X-rays in assessing extent of disease, and some CT features may discriminate an active inflammatory component (which may be amenable to therapy) from fibrosis (for which therapy is not indicated). Typical findings on HRCT include micronodules, perilymphatic and bronchocentric distribution, perihilar opacities, and varying degrees of fibrosis. Less common findings on CT include mass-like or alveolar opacities, miliary opacities, mosaic attenuation, honeycomb cysts, and cavitation. With progressive disease, fibrosis, architectural distortion, upper lobe volume loss with hilar retraction, coarse linear bands, cysts, and bullae may be observed. We discuss the salient CT findings in patients with sarcoidosis (with a major focus on pulmonary features) and present classical radiographic and histopathological images of a few extrapulmonary sites.

FRI0539 SURVIVAL IN PATIENTS WITH CONNECTIVE TISSUE DISEASE-ASSOCIATED PULMONARY ARTERIAL HYPERTENSION (CTD-PAH): A META-ANALYSIS OF OBSERVATIONAL REGISTRIES

Background:

Although patients with CTD-PAH comprise approximately one third of the overall PAH population, the literature on survival outcomes in CTD-PAH patients overall and by CTD subtype is limited by small sample sizes. We conducted a meta-analysis of more than 4,000 patients with CTD-PAH enrolled in observational registries.

Objectives:

To determine survival rates in patients with CTD-PAH overall and by CTD subtypes.

Methods:

The PubMed and EMBASE databases were searched for English-only articles published between January 1, 2000 and November 25, 2019. Inclusion criteria were multicenter registries of adults with WHO group 1 pulmonary hypertension (PAH); conducted in 2000 or later; and survival data for ≥30 patients with CTD-PAH. Meta-analysis of survival was performed using a random-effects model. Survival was estimated for CTD-PAH overall; for CTD-PAH stratified by registries primarily conducted before and after 2010 to assess the impact of new therapies, as well as combination therapy approaches targeting multiple pathways; and for CTD subtypes (systemic sclerosis [SSc] and systemic lupus erythematosus [SLE]).

Results:

Nineteen registries met inclusion criteria and reported data on 4,008 patients with CTD-PAH. Of these patients, 1,485 had SSc, 456 had SLE, and CTD subtype was not specified in 2,067. CTD-PAH patients had a mean age of 55 years and 87% were female. Most patients (70%) had functional class III or IV disease and the mean 6-minute walk distance at enrollment was 327 m. Among registries that enrolled patients of all PAH etiologies (N=7,829), survival rates in the CTD-PAH subpopulation (n=2113), were 83%, 73%, and 62% at 1-, 2-, and 3- years, respectively. These survival rates were lower than those reported for the overall PAH population: 88%, 79%, and 72% at 1-, 2-, and 3- years, respectively. Numerically higher survival rates at 1-, 2-, and 3- years were observed in CTD-PAH patients treated in 2010 and later: 85% vs 90%, 74% vs 82%, and 65% vs 73%. Among all CTD-PAH patients, survival rates were lower for patients with SSc compared to those with SLE: 88% vs 92%, 75% vs 90%, 67% vs 87% at 1-, 2-, and 3- years, respectively (Figure).

Conclusion:

Patients with CTD-PAH have a substantial risk of death, however, CTD-PAH patients treated within the last ten years have numerically higher survival rates than those treated earlier. This may be related to increased screening for PAH, especially in SSc (leading to earlier diagnosis) and/or the availability of new treatment approaches. Consistent with clinical observations, patients with SSc have worse survival rates than those with SLE. Given the high risk of mortality in these patients, early detection and upfront aggressive treatment are warranted.

References:

Acknowledgments:

This analysis was funded by Actelion Pharmaceuticals.

Disclosure of Interests:

Dinesh Khanna Shareholder of: Eicos, Grant/research support from: NIH NIAID, NIH NIAMS, Consultant of: Acceleron, Actelion, Bayer, BMS, Boehringer-Ingelheim, Corbus, Galapagos, Genentech/Roche, GSK, Mitsubishi Tanabi, Sanofi-Aventis/Genzyme, UCB Pharma, Carol Zhao Shareholder of: Actelion Pharmaceuticals US, Inc., Employee of: Actelion Pharmaceuticals US, Inc., Lorinda Chung Grant/research support from: United Therapeutics, Boehringer Ingelheim, Consultant of: Bristol-Myers Squibb, Boehringer Ingelheim, Mitsubishi Tanabe, Eicos Sciences, Gerry Coghlan Grant/research support from: Johnson & Johnson, Consultant of: Bayer, Johnson & Johnson, GlaxoSmithKline, Speakers bureau: Bayer, Johnson & Johnson, GlaxoSmithKline, Rajan Saggar Grant/research support from: Actelion, Gilead Science, United Therapeutics, Consultant of: Actelion, Gilead Science, United Therapeutics, Speakers bureau: Actelion, Gilead Science, United Therapeutics, Stephen Mathai Consultant of: Actelion, Liquidia, Arena, United Therapeutics, Mehul Shah Shareholder of: Actelion Pharmaceuticals US, Inc, Employee of: Actelion Pharmaceuticals US, Inc, John Hartney Shareholder of: Actelion Pharmaceuticals US, Inc, Employee of: Actelion Pharmaceuticals US, Inc, Vallerie McLaughlin Grant/research support from: Reata Pharmaceutics, SoniVie, United Therapeutics, Bayer, Acceleron, Actelion Pharmaceuticals US, Inc., Consultant of: Actelion Pharmaceuticals US, Inc., Acceleron, Arena Pharmaceuticals, Bayer, Caremark, CiVi Biopharma, United Therapeutics

1262 Case Series on the Use of Volume Assured Pressure Support (VAPS) in Patients with Interstitial Lung Disease and Progressive Hypercapnia

Introduction

Many patients with interstitial lung disease (ILD) experience progressive respiratory failure. While various therapies are implemented for acute hypercapnic respiratory failure during inpatient ILD flares, there is little data regarding the management of chronic hypercapnia in ILD with nocturnal Volume Assured Pressure Support (VAPS). We present three patients who were prescribed nocturnal VAPS for their progressive hypercapnia as a bridge to lung transplantation.

Report of Case

Patient 1 is a 45-year-old woman with rheumatoid arthritis related ILD and progressive hypercapnia. Despite optimal therapy, her ILD resulted in an admission for hypercapnic and hypoxemic respiratory failure requiring treatment with BPAP, then transition to nocturnal VAPS on discharge. Dyspnea and pCO2 improved as an outpatient (Fig. 1). Patient 2 is a 70-year-old female with history of scleroderma associated ILD with severe PH and hypercapnia. Initiation of VAPS improved her pCO2 levels although she was readmitted after a few months of treatment for an ILD flare. Patient 3 is a 60-year-old patient with connective tissue disease related ILD who was admitted for respiratory failure due to pneumonia and was transitioned to BPAP for hypercapnic respiratory failure. Due to insurance issues she has been unable to obtain a home VAPS and her pCO2 remains elevated. A plot of each patient’s pCO2 over time is in Figure 1.

Conclusion

In patients with severe lung disease, the normal decrease in tidal volumes that occurs with sleep can result in CO2 retention. Non-invasive ventilation (NIV) is well-studied in both stable obstructive lung disease and exacerbations but there is little data examining the utility of NIV to treat the chronic hypercapnia of ILD. In this case series, nocturnal VAPS stabilized or reduced PCO2 in patients with ILD and hypercapnia. Additional studies are needed to assess long term effects of VAPS in these patients.

BOLA (BolA Family Member 3) Deficiency Controls Endothelial Metabolism and Glycine Homeostasis in Pulmonary Hypertension

BACKGROUND

Deficiencies of iron-sulfur (Fe-S) clusters, metal complexes that control redox state and mitochondrial metabolism, have been linked to pulmonary hypertension (PH), a deadly vascular disease with poorly defined molecular origins. BOLA3 (BolA Family Member 3) regulates Fe-S biogenesis, and mutations in BOLA3 result in multiple mitochondrial dysfunction syndrome, a fatal disorder associated with PH. The mechanistic role of BOLA3 in PH remains undefined.

METHODS

In vitro assessment of BOLA3 regulation and gain- and loss-of-function assays were performed in human pulmonary artery endothelial cells using siRNA and lentiviral vectors expressing the mitochondrial isoform of BOLA3. Polymeric nanoparticle 7C1 was used for lung endothelium-specific delivery of BOLA3 siRNA oligonucleotides in mice. Overexpression of pulmonary vascular BOLA3 was performed by orotracheal transgene delivery of adeno-associated virus in mouse models of PH.

RESULTS

In cultured hypoxic pulmonary artery endothelial cells, lung from human patients with Group 1 and 3 PH, and multiple rodent models of PH, endothelial BOLA3 expression was downregulated, which involved hypoxia inducible factor-2α-dependent transcriptional repression via histone deacetylase 1-mediated histone deacetylation. In vitro gain- and loss-of-function studies demonstrated that BOLA3 regulated Fe-S integrity, thus modulating lipoate-containing 2-oxoacid dehydrogenases with consequent control over glycolysis and mitochondrial respiration. In contexts of siRNA knockdown and naturally occurring human genetic mutation, cellular BOLA3 deficiency downregulated the glycine cleavage system protein H, thus bolstering intracellular glycine content. In the setting of these alterations of oxidative metabolism and glycine levels, BOLA3 deficiency increased endothelial proliferation, survival, and vasoconstriction while decreasing angiogenic potential. In vivo, pharmacological knockdown of endothelial BOLA3 and targeted overexpression of BOLA3 in mice demonstrated that BOLA3 deficiency promotes histological and hemodynamic manifestations of PH. Notably, the therapeutic effects of BOLA3 expression were reversed by exogenous glycine supplementation.

CONCLUSIONS

BOLA3 acts as a crucial lynchpin connecting Fe-S-dependent oxidative respiration and glycine homeostasis with endothelial metabolic reprogramming critical to PH pathogenesis. These results provide a molecular explanation for the clinical associations linking PH with hyperglycinemic syndromes and mitochondrial disorders. These findings also identify novel metabolic targets, including those involved in epigenetics, Fe-S biogenesis, and glycine biology, for diagnostic and therapeutic development.

Mitochondrial DNA Stimulates TLR9-Dependent Neutrophil Extracellular Trap Formation in Primary Graft Dysfunction

The immune system is designed to robustly respond to pathogenic stimuli but to be tolerant to endogenous ligands to not trigger autoimmunity. Here, we studied an endogenous damage-associated molecular pattern, mitochondrial DNA (mtDNA), during primary graft dysfunction (PGD) after lung transplantation. We hypothesized that cell-free mtDNA released during lung ischemia-reperfusion triggers neutrophil extracellular trap (NET) formation via TLR9 signaling. We found that mtDNA increases in the BAL fluid of experimental PGD (prolonged cold ischemia followed by orthotopic lung transplantation) and not in control transplants with minimal warm ischemia. The adoptive transfer of mtDNA into the minimal warm ischemia graft immediately before lung anastomosis induces NET formation and lung injury. TLR9 deficiency in neutrophils prevents mtDNA-induced NETs, and TLR9 deficiency in either the lung donor or recipient decreases NET formation and lung injury in the PGD model. Compared with human lung transplant recipients without PGD, severe PGD was associated with high levels of BAL mtDNA and NETs, with evidence of relative deficiency in DNaseI. We conclude that mtDNA released during lung ischemia-reperfusion triggers TLR9-dependent NET formation and drives lung injury. In PGD, DNaseI therapy has a potential dual benefit of neutralizing a major NET trigger (mtDNA) in addition to dismantling pathogenic NETs.

Endotype-phenotyping may predict a treatment response in progressive fibrosing interstitial lung disease

Background

Some interstitial lung disease (ILD) patients develop a progressive fibrosing-ILD phenotype (PF-ILD), with similar persistent lung function decline suggesting common molecular pathways involved. Nintedanib, a tyrosine kinase inhibitor targeting the PDGF, FGF, VEGF and M-CSF pathways, has shown comparable efficacy in idiopathic pulmonary fibrosis (IPF) and systemic sclerosis-associated ILD (SSc-ILD). We hypothesize that Nintedanib targeted molecular pathways will be augmented to a similar degree across PF-ILD regardless of aetiology.

Methods

We collected explanted lung tissue at the time of lung transplantation from 130 PF-ILD patients (99 (76%) IPF, 14 (11%) SSc-ILD, 17 (13%) other PF-ILD), and wedge biopsies from 200 donor lungs and measured PDGF, FGF, VEGF and M-CSF concentrations by Luminex.

Findings

The concentrations of PDGF-AA, PDGF-BB, FGF-2, VEGF and M-CSF were significantly increased in PF-ILD lungs compared to donor lungs (PDGF-AA 93·0 pg/ml [±97·2] vs. 37·5 pg/ml [±35·4], p < 0·001; PDGF-BB 102·5 pg/ml [±78·8] vs. 61·9 pg/ml [±47·0], p < 0·001; FGF-2 1442·4 pg/ml [±426·6] vs. 1201·7 pg/ml [±535·2], p = 0·009; VEGF 40·6 pg/ml [±20·1] vs. 24·9 pg/ml [±29·5], p < 0·001; and M-CSF 25526 pg/ml [±24,799] vs. 6120 pg/ml [±7245], p < 0·001). There were no significant differences in these growth factor/angiogenic molecules/cytokine concentrations when segregated by IPF, SSc-ILD and other PF-ILDs.

Interpretation

Nintedanib specific targeted molecular pathways are augmented to a similar magnitude in all PF-ILD lung tissue as compared to controls, suggesting that Nintedanib treatment may be efficacious in PF-ILD regardless of aetiology. We speculate that clinical trials using Nintedanib for PF-ILD with or without IPF or SSc-ILD should show a similar relative reduction in FVC decline as seen in IPF and SSc-ILD (∼45–50%).

Funding

Health Grant P01-HL108793 (JAB), South-Eastern Norway Regional Health Authority Grant 2018072 (AMHV).

A review of exercise pulmonary hypertension in systemic sclerosis

In general, pulmonary vascular disease has important negative prognostic implications, regardless of the associated condition or underlying mechanism. In this regard, systemic sclerosis is of particular interest as it is the most common connective tissue disease associated with pulmonary hypertension, and a well-recognized at-risk population. In the setting of systemic sclerosis and unexplained dyspnea, the concept of using exercise to probe for underlying pulmonary vascular disease has acquired significant interest. In theory, a diagnosis of systemic sclerosis-associated exercise pulmonary hypertension may allow for earlier therapeutic intervention and a favorable alteration in the natural history of the pulmonary vascular disease. In the context of underlying systemic sclerosis, the purpose of this article is to provide a comprehensive review of the evolving definition of exercise pulmonary hypertension, the current role and methodologies for non-invasive and invasive exercise testing, and the importance of the right ventricle.

Histological hallmarks and role of Slug/PIP axis in pulmonary hypertension secondary to pulmonary fibrosis

Pulmonary hypertension secondary to pulmonary fibrosis (PF-PH) is one of the most common causes of PH, and there is no approved therapy. The molecular signature of PF-PH and underlying mechanism of why pulmonary hypertension (PH) develops in PF patients remains understudied and poorly understood. We observed significantly increased vascular wall thickness in both fibrotic and non-fibrotic areas of PF-PH patient lungs compared to PF patients. The increased vascular wall thickness in PF-PH patients is concomitant with a significantly increased expression of the transcription factor Slug within the macrophages and its target prolactin-induced protein (PIP), an extracellular matrix protein that induces pulmonary arterial smooth muscle cell proliferation. We developed a novel translational rat model of combined PF-PH that is reproducible and shares similar histological features (fibrosis, pulmonary vascular remodeling) and molecular features (Slug and PIP upregulation) with human PF-PH. We found Slug inhibition decreases PH severity in our animal model of PF-PH. Our study highlights the role of Slug/PIP axis in PF-PH.

Abstract 494: Role of Slug / PIP Axis in Pulmonary Hypertension Secondary to Pulmonary Fibrosis

Pulmonary hypertension (PH) secondary to pulmonary fibrosis (PF-PH) is the second most common cause of PH. While never studied in detail, pathology reports suggest that vascular remodeling (VR) differs between PF and PF-PH. In PF, VR is mainly limited to fibrotic areas, whereas in PF-PH, it also exist in non-fibrotic areas. These histological differences suggest potential molecular differences. To better understand this mechanism, we investigated the expression of the transcription factor Slug which is known to play a role in PH and PF.

Using explanted rat (n=7/group) and human (n=7-14/group) lungs, we compared lung fibrosis, VR and Slug expression between non-fibrotic and fibrotic areas in PF and PF-PH. Online microarray data (GSE24988) were used to find the targets of Slug that are implicated in VR. A new animal model recapitulating our findings in patients was used to test the therapeutic potential of Slug inhibition (n=10/group). This model is based on intra-tracheal instillation of bleomycin (2.5mg/Kg) at day 0 and 2weeks later, an injection of monocrotaline (60mg/kg). PH was assessed by right ventricular systolic pressure (RVSP). P<0.05 are considered significant.

In both PF and PF-PH patients, fibrotic areas (PF29±4; PF-PH37±3) exhibit significantly increased VR when compared to non-fibrotic areas of the lung (PF 22±1; PF-PH 31±6). PF-PH patients have increased pulmonary vascular thickening in both areas vs PF patients. This is concomitant with an increased number of Ki67+ vascular cells in PF-PH (12±2%) vs PF (8±1%) as well as an upregulation of Slug in PF-PH patients (2.3±0.5) vs PF (1±0.1). Co-immunolabeling with CD68 demonstrate that macrophages are the main cell type responsible for Slug up-regulation in PF-PH. Human microarray data reveal an up-regulation of the Prolactin-induced protein (PIP) in PF-PH vs PF (9±3 vs 1±0.4). PIP is an extracellular transcriptional target of Slug, known to promote cell proliferation. In-vitro, PIP significantly increases pulmonary arterial smooth muscle cell proliferation in a dose dependent manner. Finally, Slug inhibition decreases RVSP (47±3 vs 62±3mmHg) in an animal model of PF-PH.

There are histological differences between PF-PH and PF lungs that are at least in part mediated by a Slug/PIP axis leading to VR.

Pulmonary tumor thrombotic microangiopathy: a systematic review

Pulmonary tumor thrombotic microangiopathy (PTTM) is a fatal disease process in which pulmonary hypertension (PH) develops in the setting of malignancy. The purpose of this study is to present a detailed analysis of cases of PTTM reported in literature in the hopes of achieving more ante-mortem diagnoses. We conducted a systematic review of currently published and available cases of PTTM by searching the term “pulmonary tumor thrombotic microangiopathy” on the Pubmed.gov database. Seventy-nine publications were included consisting of 160 unique cases of PTTM. The most commonly reported malignancy was gastric adenocarcinoma (94 cases, 59%). Cough and dyspnea were reported in 61 (85%) and 102 (94%) cases, respectively. Hypoxemia was reported in 96 cases (95%). Elevation in D-dimer was noted in 36 cases (95%), presence of anemia in 32 cases (84%), and thrombocytopenia in 30 cases (77%). Common findings on chest computed tomography (CT) included ground-glass opacities (GGO) in 28 cases (82%) and nodules in 24 cases (86%). PH on echocardiography was noted in 59 cases (89%) with an average right ventricular systolic pressure of 71 mmHg. Common features of PTTM that are reported across the published literature include presence of dyspnea and cough, hypoxemia, with abnormal CT findings of GGO, nodules, and mediastinal/hilar lymphadenopathy, and PH. PTTM is a universally fatal disease process and this analysis provides a detailed examination of all the available published data that may help clinicians establish an earlier diagnosis of PTTM.