Pulmonary function in primary pulmonary hypertension

AbstractObjectivesThe study was done to ascertain the degree to which abnormalities in resting lung function correlate with the disease severity of patients with primary pulmonary hypertension (PPH).BackgroundPatients with PPH are often difficult to diagnose until several years after the onset of symptoms. Despite the seriousness of the disorder, the diagnosis of PPH is often delayed because it is unsuspected and requires invasive measurements. Although PPH often causes abnormalities in resting lung function, these abnormalities have not been shown to be statistically significant when correlated with other measures of PPH severity.MethodsResting lung mechanics and diffusing capacity for carbon monoxide DLcowere assessed in 79 patients whose findings conformed to the classical diagnostic criteria of PPH and who had no evidence of secondary causes of pulmonary hypertension. These findings were correlated with severity of disease as assessed by cardiac catheterization, New York Heart Association (NYHA) class, and cardiopulmonary exercise testing.ResultsWhen PPH patients were first evaluated at our referral clinic, the DLcoand lung volumes were decreased in approximately three-quarters and one-half, respectively. The decreases in DLco, and to a lesser extent lung volumes, correlated significantly with decreases in peak oxygen uptake (reflecting maximum cardiac output), peak oxygen pulse (reflecting maximum stroke volume), and anaerobic threshold (reflecting sustainable exercise capacity) and higher NYHA class.ConclusionsPatients with PPH commonly have abnormalities in lung mechanics and DLcolevels that correlate significantly with disease severity. These measurements can be useful in evaluating patients with unexplained dyspnea and fatigue

Successful Tricuspid Valve Replacement in a Patient with Severe Pulmonary Arterial Hypertension and Preserved Right Ventricular Systolic Function

A 56-year-old patient with severe pulmonary hypertension developed severe tricuspid regurgitation, right-sided heart failure, and congestive hepatopathy. She was transferred for possible lung transplant and/or tricuspid valve surgery. Clinical and echocardiographic assessment provided confidence that acute tricuspid valve failure was responsible for the decompensation and that tricuspid valve replacement despite pulmonary hypertension could be performed

Care of patients with pulmonary arterial hypertension during the coronavirus (COVID-19) pandemic

The COVID-19 pandemic presents many unique challenges when caring for patients with pulmonary hypertension. The COVID-19 pandemic has altered routine standard of care practice and the acute management particularly for those patients with pulmonary arterial hypertension, where pulmonary arterial hypertension-specific treatments are used. It is important to balance the ongoing care and evaluation of pulmonary arterial hypertension patients with exposure risk to COVID-19 for patients coming to clinic or the hospital. If there is a morbidity and mortality benefit from starting pulmonary arterial hypertension therapies, for example in a patient with high-likelihood of pulmonary arterial hypertension, then it remains important to complete the thorough evaluation. However, the COVID-19 outbreak may also represent a unique time when pulmonary hypertension experts have to weigh the risks and benefits of the diagnostic work-up including potential exposure to COVID-19 versus initiating targeted pulmonary arterial hypertension therapy in a select high-risk, high likelihood World Symposium Pulmonary Hypertension Group 1 pulmonary arterial hypertension patients. This document will highlight some of the issues facing providers, patients, and the pulmonary arterial hypertension community in real-time as the COVID-19 pandemic is evolving and is intended to share expected common clinical scenarios and best clinical practices to help the community at-large

Tadalafil for the Treatment of Pulmonary Arterial Hypertension A Double-Blind 52-Week Uncontrolled Extension Study

ObjectivesThe aim of this study was to evaluate the long-term safety and durability of efficacy of tadalafil for pulmonary arterial hypertension.BackgroundTadalafil is an oral phosphodiesterase-5 inhibitor approved for PAH treatment. In the multicenter, placebo-controlled, randomized, 16-week PHIRST (Pulmonary Arterial Hypertension and Response to Tadalafil) study, tadalafil 40 mg improved exercise capacity and delayed clinical worsening.MethodsEligible patients from PHIRST received once-daily tadalafil 20 mg (T20 mg) or 40 mg (T40 mg) (n = 357) in the double-blind, 52-week, uncontrolled extension study (PHIRST-2); 293 patients completed PHIRST-2. Durability of efficacy was explored using the 6-min walk distance (6MWD) test. Clinical worsening and changes in World Health Organization functional class were evaluated.ResultsThe safety profile of tadalafil in PHIRST-2 was similar to that in PHIRST, with typical phosphodiesterase-5 inhibitor adverse events. The 6MWDs achieved in PHIRST for the subset of patients receiving T20 mg and T40 mg in both PHIRST and PHIRST-2 (406 ± 67 m [n = 52] and 413 ± 81 m [n = 59] at PHIRST-2 enrollment, respectively) were maintained at PHIRST-2 completion (415 ± 80 m [n = 51] and 410 ± 78 m [n = 59], respectively). Numerically fewer patients who were on T40 mg in PHIRST and PHIRST-2 experienced World Health Organization functional class deterioration (6% [n = 5]) compared with those randomized to T20 mg (9% [n = 7]) across both studies. Post hoc analyses showed that background bosentan use and higher 6MWD at PHIRST baseline were associated with fewer clinical worsening events.ConclusionsLong-term treatment with tadalafil was well tolerated in patients with pulmonary arterial hypertension. In patients receiving either T20 mg or T40 mg, the improvements in 6MWD demonstrated in the 16-week PHIRST study appeared sustained for up to 52 additional weeks of treatment in PHIRST-2. (Pulmonary Arterial Hypertension and Response to Tadalafil Study; NCT00549302

Clinical outcomes stratified by baseline functional class after initial combination therapy for pulmonary arterial hypertension

Background: Initial combination therapy with ambrisentan and tadalafil reduced the risk of clinical failure events for treatment-naïve participants with pulmonary arterial hypertension (PAH) as compared to monotherapy. Previous studies in PAH have demonstrated greater treatment benefits in more symptomatic participants. Methods: AMBITION was an event-driven, double-blind study in which participants were randomized 2:1:1 to oncedaily initial combination therapy with ambrisentan 10 mg plus tadalafil 40 mg, ambrisentan 10 mg plus placebo, or tadalafil 40 mg plus placebo. In this pre-specified subgroup analysis, we compared the efficacy data between those with functional class (FC) II vs. FC III symptoms at baseline. Results: This analysis included 500 participants in the previously defined primary analysis set (n = 155 FC II, n = 345 FC III). Comparing combination therapy to pooled monotherapy, the risk of clinical failure events was reduced by 79% (hazard ratio, 0.21 [95% confidence interval: 0.071, 0.63]) for FC II patients and 42 (hazard ratio, 0.58 [95% confidence interval: 0.39, 0.86]) for FC III patients. In a post-hoc analysis, the risk of first hospitalization for worsening PAH was also reduced by combination therapy, particularly for FC II patients (0 combination vs. 11 [14%] pooled monotherapy). Adverse events were frequent but comparable between the subgroups. Conclusions: Treatment benefit from initial combination therapy appeared at least as great for FC II as for FC III participants. Hospitalizations for worsening PAH were not observed in FC II participants assigned to combination. The present data support an initial combination strategy for newly diagnosed patients even when symptoms are less severe

Patients with pulmonary arterial hypertension with and without cardiovascular risk factors: Results from the AMBITION trial

Background: The purpose of this study was to compare patients with pulmonary arterial hypertension enrolled in the AMBITION trial with (excluded from the primary analysis set [ex-primary analysis set]) and without (primary analysis set) multiple risk factors for left ventricular diastolic dysfunction. Methods: Treatment-naive patients with pulmonary arterial hypertension were randomized to once-daily ambrisentan and tadalafil combination therapy, ambrisentan monotherapy, or tadalafil monotherapy. The primary end point was time from randomization to first adjudicated clinical failure event. Results: Primary analysis set patients (n = 500), compared with ex-primary analysis set patients (n = 105), were younger (mean, 54.4 vs 62.1 years) with greater baseline 6-minute walk distance (median, 363.7 vs 330.5 meters) and fewer comorbidities (e.g., hypertension and diabetes). Treatment effects of initial combination therapy vs pooled monotherapy were directionally the same for both populations, albeit of a lower magnitude for ex-primary analysis set patients. Initial combination therapy reduced the risk of clinical failure compared with pooled monotherapy in primary analysis set patients (hazard ratio, 0.50; 95% confidence interval, 0.35-0.72), whereas the effect was less clear in ex-primary analysis set patients (hazard ratio, 0.70; 95% confidence interval, 0.35-1.37). Overall, primary analysis set patients had fewer clinical failure events (25% vs 33%), higher rates of satisfactory clinical response (34% vs 24%), and lower rates of permanent study drug withdrawal due to adverse events (16% vs 31%) than ex-primary analysis set patients. Conclusions: Efficacy of initial combination therapy vs pooled monotherapy was directionally similar for primary analysis set and ex-primary analysis set patients. However, ex-primary analysis set patients (with multiple risk factors for left ventricular diastolic dysfunction) experienced higher rates of clinical failure events and the response to combination therapy vs monotherapy was attenuated. Tolerability was better in primary analysis set than ex-primary analysis set patients

Developing Pulmonary Vasculopathy in Systemic Sclerosis, Detected with Non-Invasive Cardiopulmonary Exercise Testing

BACKGROUND: Patients with systemic sclerosis (SSc) may develop exercise intolerance due to musculoskeletal involvement, restrictive lung disease, left ventricular dysfunction, or pulmonary vasculopathy (PV). The latter is particularly important since it may lead to lethal pulmonary arterial hypertension (PAH). We hypothesized that abnormalities during cardiopulmonary exercise testing (CPET) in patients with SSc can identify PV leading to overt PAH. METHODS: Thirty SSc patients from the Harbor-UCLA Rheumatology clinic, not clinically suspected of having significant pulmonary vascular disease, were referred for this prospective study. Resting pulmonary function and exercise gas exchange were assessed, including peakVO2, anaerobic threshold (AT), heart rate-VO2 relationship (O2-pulse), exercise breathing reserve and parameters of ventilation-perfusion mismatching, as evidenced by elevated ventilatory equivalent for CO2 (VE/VCO2) and reduced end-tidal pCO2 (PETCO2) at the AT. RESULTS: Gas exchange patterns were abnormal in 16 pts with specific cardiopulmonary disease physiology: Eleven patients had findings consistent with PV, while five had findings consistent with left-ventricular dysfunction (LVD). Although both groups had low peak VO2 and AT, a higher VE/VCO2 at AT and decreasing PETCO2 during early exercise distinguished PV from LVD. CONCLUSIONS: Previously undiagnosed exercise impairments due to LVD or PV were common in our SSc patients. Cardiopulmonary exercise testing may help to differentiate and detect these disorders early in patients with SSc

Rare variant analysis of 4241 pulmonary arterial hypertension cases from an international consortium implicates FBLN2, PDGFD, and rare de novo variants in PAH

Abstract: Background: Pulmonary arterial hypertension (PAH) is a lethal vasculopathy characterized by pathogenic remodeling of pulmonary arterioles leading to increased pulmonary pressures, right ventricular hypertrophy, and heart failure. PAH can be associated with other diseases (APAH: connective tissue diseases, congenital heart disease, and others) but often the etiology is idiopathic (IPAH). Mutations in bone morphogenetic protein receptor 2 (BMPR2) are the cause of most heritable cases but the vast majority of other cases are genetically undefined. Methods: To identify new risk genes, we utilized an international consortium of 4241 PAH cases with exome or genome sequencing data from the National Biological Sample and Data Repository for PAH, Columbia University Irving Medical Center, and the UK NIHR BioResource – Rare Diseases Study. The strength of this combined cohort is a doubling of the number of IPAH cases compared to either national cohort alone. We identified protein-coding variants and performed rare variant association analyses in unrelated participants of European ancestry, including 1647 IPAH cases and 18,819 controls. We also analyzed de novo variants in 124 pediatric trios enriched for IPAH and APAH-CHD. Results: Seven genes with rare deleterious variants were associated with IPAH with false discovery rate smaller than 0.1: three known genes (BMPR2, GDF2, and TBX4), two recently identified candidate genes (SOX17, KDR), and two new candidate genes (fibulin 2, FBLN2; platelet-derived growth factor D, PDGFD). The new genes were identified based solely on rare deleterious missense variants, a variant type that could not be adequately assessed in either cohort alone. The candidate genes exhibit expression patterns in lung and heart similar to that of known PAH risk genes, and most variants occur in conserved protein domains. For pediatric PAH, predicted deleterious de novo variants exhibited a significant burden compared to the background mutation rate (2.45×, p = 2.5e−5). At least eight novel pediatric candidate genes carrying de novo variants have plausible roles in lung/heart development. Conclusions: Rare variant analysis of a large international consortium identified two new candidate genes—FBLN2 and PDGFD. The new genes have known functions in vasculogenesis and remodeling. Trio analysis predicted that ~ 15% of pediatric IPAH may be explained by de novo variants