Cardiac effort and 6-min walk distance correlate with stroke volume measured by cardiac magnetic resonance imaging

Right ventricular (RV) dysfunction in pulmonary arterial hypertension (PAH) is associated with poor outcomes. Cardiac magnetic resonance imaging (cMRI) is the gold standard for volumetric assessment, and few reports have correlated 6-min walk distance (6MWD) and cMRI parameters in PAH. Cardiac Effort, (the number of heart beats used during 6-min walk test)/(6MWD), incorporates physiologic changes into walk distance and has been associated with stroke volume (SV) measured by nuclear imaging and indirect Fick. Here, we aimed to interrogate the relationship of Cardiac Effort and 6MWD with SV measured by the gold standard, cMRI. This was a single-center, observational, prospective study in Group 1 PAH patients. Subjects completed 6-min walk with heart rate monitoring (Cardiac Effort) and cMRI within 24 h. cMRI was correlated to Cardiac Effort and 6MWD using Spearman Correlation Coefficient. Twenty-five participants with a wide range of RV function completed both cMRI and Cardiac Effort. There was a strong correlation between left ventricle SV index and both Cardiac Effort (r = -0.70, p = 0.0001) and 6MWD (r = 0.67, p = 0.0002). Cardiac Effort and 6MWD were statistically separated in patients at prognostically significant thresholds of left ventricle SV index (>31 ml/m2), RV Ejection Fraction (>35%), and SV/End Systolic Volume ( > 0.53). Cardiac Effort and 6MWD are noninvasive ways to gain insight into those with impaired SV. 6MWD may correlate better with SV than previously thought and heart rate monitoring provides physiologic context to the walk distance obtained.

Oral Treprostinil is Associated with Improved Survival in FREEDOM-EV and its Open-Label Extension

INTRODUCTION

In the event-driven FREEDOM-EV trial, oral treprostinil delayed clinical worsening in patients with pulmonary arterial hypertension (PAH). Open-label extension studies offer additional data about tolerability, efficacy, and survival, especially for those initially assigned placebo. The aim of the current study was to determine if oral treprostinil changed survival when considering the parent and extension study, if treprostinil provides functional benefits for participants initially assigned to placebo, and if the benefits observed for those treated with treprostinil were durable.

METHODS

Both active and placebo participants from FREEDOM-EV could enroll in the FREEDOM-EV open-label extension (OLE) study after experiencing an investigator-assessed clinical worsening event or after parent study closure. All participants in the OLE were offered open-label oral treprostinil. Previously assigned placebo participants titrated to maximally tolerated doses; previously assigned treprostinil participants continued dose titration. We repeated assessments including functional class and 6-min walk distance (6MWD) at 12-week intervals and measured N-terminal pro-brain natriuretic peptide (NT-proBNP) at week 48. Survival was estimated by Kaplan-Meier analysis, and we estimated hazard ratio (HR) using Cox proportional hazards.

RESULTS

Of 690 FREEDOM-EV participants, 470 enrolled in the OLE; vital status was available for 89% of initial Freedom-EV participants. When considering the combined parent and open-label data, initial assignment to oral treprostinil reduced mortality (HR 0.64, 95% confidence interval 0.46-0.91, p = 0.013); absolute risk reduction was 9%. Participants randomized to placebo who initiated oral treprostinil after clinical worsening and tolerated treatment through week 48 demonstrated favorable shifts in functional class (p < 0.0001), 6MWD improvements of + 84 m (p < 0.0001), and a reduction in NT-proBNP of - 778 pg/mL (p = 0.02), compared to OLE baseline. Modest trends toward benefit were measured for those initially assigned placebo who did not have clinical worsening, and 132/144 (92%) of treprostinil assigned participants without clinical worsening remained on drug at week 48 in the OLE study. Adverse events were consistent with FREEDOM-EV.

CONCLUSION

Initial treprostinil assignment improved survival in the entire data set; those who began treprostinil after a clinical worsening in the placebo arm and tolerated drug to week 48 enjoyed substantial functional gains.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov identifier NCT01560637.

Regional Variation in Pulmonary Arterial Hypertension in the United States: The Pulmonary Hypertension Association Registry

Rationale: Pulmonary arterial hypertension (PAH) is a heterogeneous disease within a complex diagnostic and treatment environment. Other complex heart and lung diseases have substantial regional variation in characteristics and outcomes; however, this has not been previously described in PAH. Objectives: To identify baseline differences between U.S. census regions in the characteristics and outcomes for participants in the Pulmonary Hypertension Association Registry (PHAR). Methods: Adults with PAH were divided into regional groups (Northeast, South, Midwest, and West), and baseline differences between census regions were presented. Kaplan-Meier survival analyses and Cox proportional hazards were used to estimate the association between region and mortality in unadjusted and adjusted models. Results: Substantial differences by census regions were seen in age, race, ethnicity, marital status, employment, insurance payor breakdown, active smoking, and current alcohol use. Differences were also seen in PAH etiology and baseline 6-minute walk distance test results. Treatment characteristics varied by census region, and mortality appeared to be lower in PHAR participants in the West (hazard ratio, 0.60; 95% confidence interval, 0.43-0.83, P = 0.005). This difference was not readily explained by differences in demographic characteristics, PAH etiology, baseline severity, baseline medication regimen, or disease prevalence. Conclusions: The present study suggests significant regional variation among participants at accredited pulmonary vascular disease centers in multiple baseline characteristics and mortality. This variation may have implications for clinical research planning and represent an important focus for further study to better understand whether there are remediable care aspects that can be addressed in the pursuit of providing equitable care in the United States.

Peak steps: Capacity for activity improves after adding approved therapy in pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) patients have low activity. Activity intensity or duration could be a measure of clinical status or improvement. We aimed to determine whether standard or novel actigraphy measures could detect increases in activity after adding therapy. This was a prospective, single-center observational study evaluating activity after adding therapy in Group 1 PAH; we also report a validation cohort. For our study, two different accelerometers were used, a wrist (ActiGraph) and chest (MC10) device. Patients were analyzed in two groups, Treatment Intensification (TI, adding therapy) or Stable. Both groups had baseline monitoring periods of 7 days; the TI group had follow-up at 3 months, while Stables had follow-up within 4 weeks to assess stability. Activity time and steps were reported from both devices' proprietary algorithms. In ActiGraph only, steps in 1-min intervals throughout the day were ranked (not necessarily contiguous). Average values for each week were calculated and compared using nonparametric testing. Thirty patients had paired data (11 Stable and 19 TI). There was no between-group difference at baseline; we did not observe therapy-associated changes on average daily steps or activity time/intensity. The top 5 min of steps (capacity) increased after adding therapy; there was no difference in the stable group. This key finding was validated in a previously reported randomized trial studying a behavioral intervention to increase exercise. Total daily activity metrics are influenced by both disease and non-disease factors, making therapy-associated change difficult to detect. Peak minute steps were a treatment-responsive marker in both a pharmacologic and training intervention.

Evaluation of Clinical Recovery After Surgical Treatment for Hand Ischemia From Vasospastic and Occlusive Disease Using PROMIS

BACKGROUND

There is a paucity of literature describing the recovery trajectory after surgery for upper extremity ischemia. Using Patient-Reported Outcomes Measurement Information System (PROMIS) Physical Function (PF), Upper Extremity (UE), Pain Interference (PI), and Depression domains, we aimed to describe the postoperative recovery of such patients.

METHODS

We queried our PROMIS database for patients undergoing surgery for vasospastic or occlusive disease over a 4.5-year period. Inclusion criteria were preoperative, early (average 3 weeks) and late (average 6 months) postoperative PROMIS PF and/or UE, PI, and Depression scores. The change in PROMIS scores was calculated for each time point. Changes in PROMIS scores were compared with minimal clinically important difference estimates.

RESULTS

We identified 13 patients undergoing 13 surgical interventions that met inclusion criteria. More than one-half of our patients were men (n = 7 [54%]), and more than one-half of the surgeries (n = 7 [54%]) were for isolated occlusive diagnoses, with the remainder for vasospastic disease. At short-term postoperative follow-up, the change in PROMIS PF, UE, PI, and Depression scores was -6.34 (SD: 9.13), -6.81 (SD: 9.61), 3.16 (SD: 5.78), and -3.05 (SD: 8.37), respectively. At mid-term postoperative follow-up, the change in PROMIS PF, UE, PI, and Depression scores was 4.45 (SD: 10.33), 8.04 (SD: 13.84), -7.03 (SD: 7.06), and -12.27 (SD: 10.85), respectively.

CONCLUSIONS

Our findings suggest patients undergoing surgical treatment for upper extremity ischemia experience a worsening of functional symptoms initially, as expected, followed by notable improvement.

Cardiac Effort to Compare Clinic and Remote 6-Minute Walk Testing in Pulmonary Arterial Hypertension

BACKGROUND

The SARS-CoV-2 pandemic has limited objective physiologic assessments. A standardized remote alternative is not currently available. "Cardiac effort" (CE), that is, the total number of heart beats divided by the 6-min walk test (6MWT) distance (beats/m), has improved reproducibility in the 6MWT and correlated with right ventricular function in pulmonary arterial hypertension.

RESEARCH QUESTION

Can a chest-based accelerometer estimate 6MWT distance remotely? Is remote cardiac effort more reproducible than 6MWT distance when compared with clinic assessment?

STUDY DESIGN AND METHODS

This was a single-center, prospective observational study, with institutional review board approval, completed between October 2020 and April 2021. Group 1 subjects with pulmonary arterial hypertension, receiving stable therapy for > 90 days, completed four to six total 6MWTs during a 2-week period to assess reproducibility. The first and last 6MWTs were performed in the clinic; two to four remote 6MWTs were completed at each participant's discretion. Masks were not worn. BioStamp nPoint sensors (MC10) were worn on the chest to measure heart rate and accelerometry. Two blinded readers counted laps, using accelerometry data obtained on the clinic or user-defined course. Averages of clinic variables and remote variables were used for Wilcoxon matched-pairs signed rank tests, Bland-Altman plots, or Spearman correlation coefficients.

RESULTS

Estimated 6MWT distance, using the MC10, correlated strongly with directly measured 6MWT distance (r = 0.99; P < .0001; in 20 subjects). Remote 6MWT distances were shorter than clinic 6MWT distances: 405 m (330-464 m) vs 389 m (312-430 m) (P = .002). There was no difference between in-clinic and remote CE: 1.75 beats/m (1.48-2.20 beats/m) vs 1.86 beats/m (1.57-2.14 beats/m) (P = .14).

INTERPRETATION

Remote 6MWT was feasible on a user-defined course; 6MWT distance was shorter than clinic distance. CE calculated by chest heart rate and accelerometer-estimated distance provides a reproducible remote assessment of exercise tolerance, comparable to the clinic-measured value.

Efficacy and dose-response relationship of oral treprostinil in PAH patients on monotherapy or dual background therapy

Background

FREEDOM-C and FREEDOM-C2 were randomized, placebo-controlled, double-blinded international, multicenter studies investigating the use of oral treprostinil (TRE) in subjects on mono or dual background pulmonary arterial hypertension (PAH) therapies. Both had a primary endpoint of change in 6-minute walk distance (6MWD) at Week 16 vs baseline. Previous post-hoc analyses combining mono and dual therapy subjects (PDE-5i and/or ERA) from these studies revealed a TRE dose-dependent increase in 6MWD. (1. White & Rao, 2016)

Purpose

This post-hoc analysis was performed to determine if subjects from FREEDOM-C and FREEDOM-C2 derive improvements in 6MWD with increasing doses of TRE when stratified by mono or dual background therapy and to determine if PAH background therapies (mono or dual) impacted 6MWD.

Methods

All active subjects (n=331) from FREEDOM-C and FREEDOM-C2 were grouped into TRE dose tertiles (low-dose: ≤2 mg BID, mid-dose: &gt;2 mg to ≤3.5 mg BID, and high-dose: &gt;3.5 mg BID). Placebo subjects (n=329) were in a separate 0 mg dose group. No data imputation was implemented.

Comparisons of 6MWD change at Weeks 4, 8, 12, and 16 between mono and dual therapy subgroups at any dose group were performed using a two-sample t-test or nonparametric Wilcoxon rank-sum test. The nonparametric Kruskal-Wallis test was conducted with subsequent pairwise comparisons of 6MWD change at Week 16 between the four dose groups through Dunn's approach. Additionally, the Jonckheere-Terpstra test was used to assess the linear trend for 6MWD improvement with higher doses of TRE.

Results

Baseline characteristics of the combined intention to treat (ITT) population and summary of 6MWD for subjects with both baseline and Week 16 data are in Table 1. 6MWD change improved steadily to Week 16 in subjects at higher TRE doses, regardless of the number of PAH background therapies (Figure 1). No statistical differences were found between mono and dual therapy at any time point or for any dose group. At Week 16, there was a significant difference in 6MWD change between the placebo group and high dose group within both mono and dual background therapy subjects. The difference between the low- and high-dose groups was significant for subjects on dual background therapy. There was a significant positive linear trend for TRE doses in 6MWD improvement at Week 16 for both monotherapy subjects (one-sided p-value = 0.0002) and dual therapy subjects (one-sided p-value = 0.0242).

Conclusions

6MWD improved in PAH patients regardless of their background therapy (monotherapy or dual background) and derive greater 6MWD improvements with higher doses of TRE. The observed dose-dependent 6MWD increase supports the use of TRE in sequential combination with background therapies (mono or dual).

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): United Therapeutics Corporation

Aggressive Afterload Lowering to Improve the Right Ventricle: A New Target for Medical Therapy in Pulmonary Arterial Hypertension?

Despite numerous therapeutic advances in pulmonary arterial hypertension, patients continue to suffer high morbidity and mortality, particularly considering a median age of 50 years. This article explores whether early, robust reduction of right ventricular afterload would facilitate substantial improvement in right ventricular function and thus whether afterload reduction should be a treatment goal for pulmonary arterial hypertension. The earliest clinical studies of prostanoid treatment in pulmonary arterial hypertension demonstrated an important link between lowering mean pulmonary arterial pressure (or pulmonary vascular resistance) and improved survival. Subsequent studies of oral monotherapy or sequential combination therapy demonstrated smaller reductions in mean pulmonary arterial pressure and pulmonary vascular resistance. More recently, retrospective reports of initial aggressive prostanoid treatment or initial combination oral and parenteral therapy have shown marked afterload reduction along with significant improvements in right ventricular function. Some data suggest that reaching threshold levels for pressure or resistance (components of right ventricular afterload) may be key to interrupting the self-perpetuating injury of pulmonary vascular disease in pulmonary arterial hypertension and could translate into improved long-term clinical outcomes. Based on these clues, the authors postulate that improved clinical outcomes might be achieved by targeting significant afterload reduction with initial oral combination therapy and early parenteral prostanoids.

Delphi Consensus Recommendation for Optimization of Pulmonary Hypertension Therapy Focusing On Switching from a Phosphodiesterase 5 Inhibitor to Riociguat

Dual combination therapy with a phosphodiesterase‐5 inhibitor (PDE5i) and endothelin receptor antagonist is recommended for most patients with intermediate‐risk pulmonary arterial hypertension (PAH). The RESPITE and REPLACE studies suggest that switching from a PDE5i to a soluble guanylate cyclase (sGC) activator may provide clinical improvement in this situation. The optimal approach to escalation or transition of therapy in this or other scenarios is not well defined. We developed an expert consensus statement on the transition to sGC and other treatment escalations and transitions in PAH using a modified Delphi process. The Delphi process used a panel of 20 physicians with expertise in PAH. Panelists answered three questionnaires on the management of treatment escalations and transitions in PAH. The initial questionnaire included open‐ended questions. Later questionnaires consolidated the responses into statements that panelists rated on a Likert scale from −5 (strongly disagree) to +5 (strongly agree) to determine consensus. The Delphi process produced several consensus recommendations. Escalation should be considered for patients who are at high risk or not achieving treatment goals, by adding an agent from a new class, switching from oral to parenteral prostacyclins, or increasing the dose. Switching to a new class or within a class should be considered if tolerability or other considerations unrelated to efficacy are affecting adherence. Switching from a PDE5i to an SGC activator may benefit patients with intermediate risk who are not improving on their present therapy. These consensus‐based recommendations may be helpful to clinicians and beneficial for patients when evidence‐based guidance is unavailable.

Oral treprostinil improves pulmonary vascular compliance in pulmonary arterial hypertension

Oral treprostinil has been shown to improve exercise capacity and delay disease progression in patients with pulmonary arterial hypertension (PAH), but its effects on hemodynamics are not well-characterized. The FREEDOM-EV trial was a Phase III, international, placebo-controlled, double-blind, event-driven study in 690 participants with PAH who were taking a single oral PAH therapy. FREEDOM-EV demonstrated a significantly reduced risk for clinical worsening with oral treprostinil taken three times daily and did not uncover new safety signals in PAH patients. Sixty-one participants in the FREEDOM-EV trial volunteered for a hemodynamics sub-study. Pulmonary artery compliance (PAC), a ratio of stroke volume to pulmonary pulse pressure, significantly increased from Baseline to Week 24 in the oral treprostinil group compared with the placebo group (geometric mean 26.4% active vs. -6.0% placebo; ANCOVA p=0.007). There was a significant increase in cardiac output in the oral treprostinil group compared to the placebo group (geometric mean 11.3% active vs. -6.4% placebo; ANCOVA p=0.005) and a corresponding significant reduction in pulmonary vascular resistance (PVR) (geometric mean -21.5 active vs. -1.8% placebo; ANCOVA p=0.02) from Baseline to Week 24. These data suggest that increased compliance contributes to the physiological mechanism by which oral treprostinil improves exercise capacity and delays clinical worsening for patients with PAH.

Reduced Notch1 Cleavage Promotes the Development of Pulmonary Hypertension

Clinical trials of Dll4 (Delta-like 4) neutralizing antibodies (Dll4nAbs) in cancer patients are ongoing. Surprisingly, pulmonary hypertension (PH) occurs in 14% to 18% of patients treated with Dll4nAbs, but the mechanisms have not been studied. Here, PH progression was measured in mice treated with Dll4nAbs. We detected Notch signaling in lung tissues and analyzed pulmonary vascular permeability and inflammation. Notch target gene array was performed on adult human pulmonary microvascular endothelial cells (ECs) after inhibiting Notch cleavage. Similar mechanisms were studied in PH mouse models and pulmonary arterial hypertension patients. The rescue effects of constitutively activated Notch1 in vivo were also measured. We observed that Dll4nAbs induced PH in mice as indicated by significantly increased right ventricular systolic pressure, as well as pulmonary vascular and right ventricular remodeling. Mechanistically, Dll4nAbs inhibited Notch1 cleavage and subsequently impaired lung endothelial barrier function and increased immune cell infiltration in vessel walls. In vitro, Notch targeted genes' expression related to cell growth and inflammation was decreased in human pulmonary microvascular ECs after the Notch1 inactivation. In lungs of PH mouse models and pulmonary arterial hypertension patients, Notch1 cleavage was inhibited. Consistently, EC cell-cell junction was leaky, and immune cell infiltration increased in PH mouse models. Overexpression activated Notch1-attenuated progression of PH in mice. In conclusion, Dll4nAbs led to PH development in mice by impaired EC barrier function and increased immune cell infiltration through inhibition of Notch1 cleavage in lung ECs. Reduced Notch1 cleavage in lung ECs could be an underlying mechanism of PH pathogenesis.

Comparison of chest- and wrist-based actigraphy in pulmonary arterial hypertension

Aims

Activity trackers for clinical trials and remote monitoring are appealing as they provide objective data outside of the clinic setting. Algorithms determine physical activity intensity and count steps. Multiple studies show physical inactivity in pulmonary arterial hypertension (PAH). There are no studies comparing different activity trackers worn on different parts of the body in PAH. We had patients with PAH simultaneously wear two different accelerometers, compared measures between the two devices, and correlated the measures with standard clinical metrics in PAH.

Methods and results

This was a single-centre, prospective observational study. Daily physical activity and daily total steps were measured using Actigraph GT9X Link and MC10 Biostamp nPoint for 5-10 days. Actigraph was worn on the non-dominant hand and the MC10 Biostamp nPoint was worn on the chest and leg with disposable adhesives. Twenty-two participants wore both accelerometers >12 h/day for an average 7.8 days. The average activity time measured by Actigraph was significantly higher than that measured by MC10 (251 ± 25 min vs. 113 ± 18 min, P = 0.0001). Actigraph's algorithm reported more time in light activity than moderate (190 ± 62 min vs. 60 ± 56 min, P = 0.0001). REVEAL 2.0 scores correlated highly with activity time measured using either device. Invasively measured haemodynamics within 7 days did not correlate with activity time or daily steps.

Conclusion

Different activity trackers yield discordant results in PAH patients. Further studies are needed in determining the best device, optimal wear time, and different thresholds for activities in chronic diseases.

An Untapped Resource: Characteristics of Thrombus Recovered from Intermediate or High Risk Pulmonary Embolus Patients

INTRODUCTION

Response to anticoagulation varies during management of acute hospitalized pulmonary embolism. We aimed to study thrombus histology in pulmonary embolism samples removed during acute surgical embolectomy to evaluate whether thrombus morphology was similar between patients and whether there was an association with duration of symptoms and/or resolution on follow up imaging.

METHODS

This was a retrospective observational single center study at the University of Rochester Medical Center. We evaluated patients that underwent acute surgical embolectomy and followed up in our clinic 2-4 months after the event with Ventilation/Perfusion (V/Q) scan obtained for all regardless of symptoms. Thromboemboli were formalin fixed and processed for light microscopy in the hospital histopathology laboratory. Four-micron thick sections were stained with hematoxylin and eosin, Masson trichrome, and Verhoeff elastic tissue stains. Immunohistochemistry was performed using anti-CD31 and anti-CD68. Slides were independently evaluated for time-dependent microscopic changes using Irniger's classification by two blinded pathologists.

RESULTS

Sixteen patients underwent embolectomy with fifteen having V/Q imaging at follow up. The majority of patients were female. Samples showed a generally similar overall architecture that included a central core composed primarily of red blood cells and fibrin and an outer layer of platelets and monocytes. Two samples had evidence of fibrosis and recanalization.

CONCLUSIONS

We found heterogeneous histopathology in samples obtained during acute embolectomy. Further prospective studies should systematically characterize clot morphology and evaluate treatment response and outcomes. Careful thrombus specimen measurement and consistent sampling for sections will be required to draw firm conclusions.

Vasodilator use in precapillary pulmonary hypertension with end stage kidney disease: A single center experience

BACKGROUND AND OBJECTIVES

Pulmonary hypertension is commonly seen in end stage kidney disease and is most commonly due to elevated left heart pressures. There is limited data about vasodilator use during the management of Group 1 pulmonary arterial hypertension in the context of those who also have or later developed end stage kidney disease. The objective of this study was to determine safety and efficacy of vasodilator therapy in precapillary pulmonary hypertension requiring renal replacement therapy.

DESIGN

This was a single-center retrospective case series. Patients were identified from our Pulmonary Hypertension Clinic using a historical roster from 2012 to 2020. Patients were included if they >18 years of age, had Group 1 or Group 4 (precapillary) pulmonary hypertension on right heart catheterization, and also had end stage kidney disease requiring either intermittent hemodialysis or peritoneal dialysis.

RESULTS

18 patients were identified with invasively confirmed Group 1 or Group 4 pulmonary hypertension and end stage kidney disease on renal replacement therapy. Scleroderma was the most common etiology for renal failure. 17 patients were treated with vasodilator therapy. Fifteen patients had paired right heart catheterizations that showed a significant decrease in mean pulmonary artery pressure and pulmonary vascular resistance. Therapy was relatively well tolerated but hypotension was common and midodrine was often helpful. Two patients had successful renal transplantation after starting vasodilator therapy.

CONCLUSION

We found vasodilator therapy was reasonably well tolerated and associated with a drop in mean pressure and pulmonary vascular resistance in patients with end stage kidney disease on dialysis.

Resting heart rate as a surrogate for improvement in intermediate risk pulmonary embolus patients?

BACKGROUND

Pulmonary embolism (PE) response teams (PERT) have been developed to improve in-hospital mortality. Identifying intermediate risk PE patients that will progress despite anticoagulation is difficult, especially because outcomes with modern anticoagulation are quite good.

OBJECTIVE

The primary aim of this study was to evaluate the rate of anticoagulation failure (new deep vein thrombosis or PE, right ventricular failure resulting in shock, cardiac arrest, or PE-attributable death) in intermediate risk PE patients managed by PERT. The secondary objective was to determine whether there was a significant decrease in heart rate 24 h after initiation of anticoagulation in intermediate risk PE.

METHODS

This was a retrospective observational study of patients treated for acute intermediate risk PE at the University of Rochester Medical Center who also had outpatient followup between November 2016-June 2019.

RESULTS

Ninety-two patients presented as intermediate-risk PE and had outpatient followup. Seventy-four patients were initially treated with anticoagulation. None of these patients failed anticoagulation. Of the eighteen intermediate risk patients that underwent advanced intervention, none failed anticoagulation first. There was significant decrease in resting heart rate 24 h after starting therapeutic anticoagulation, 107 beats/min vs 89 beats/min, p = 0.0001.

CONCLUSION

We did not observe anticoagulation failure in the management of acute, intermediate risk PE. Reductions in heart rate may reflect improvements in right ventricular function; we hypothesize that those whose heart rate does not fall may be optimal candidates for advanced intervention.

Selonsertib in adults with pulmonary arterial hypertension (ARROW): a randomised, double-blind, placebo-controlled, phase 2 trial

BACKGROUND

Data obtained in human lung tissue and preclinical models suggest that oxidative stress and increased apoptosis signal-regulating kinase 1 (ASK1) activity might have a prominent role in the pathobiology of pulmonary arterial hypertension (PAH). The purpose of this study was to determine the efficacy, safety, and tolerability of the ASK1 inhibitor selonsertib compared with placebo in patients with PAH.

METHODS

We did a randomised, double-blind, placebo-controlled, phase 2 trial at 46 centres located in Canada, France, Germany, Italy, the Netherlands, Spain, the UK, and the USA. Participants were aged 18-75 years and had an established diagnosis of idiopathic or hereditary PAH, or PAH associated with connective tissue disease, drugs or toxins, human immunodeficiency virus, or repaired congenital heart defects. Patients were stratified by PAH aetiology and background therapy, and randomly assigned (1:1:1:1) using an interactive voice-response or web-response system to placebo or selonsertib 2 mg, 6 mg, or 18 mg administered orally once daily. Both placebo and selonsertib were in tablet form. The primary efficacy endpoint was change in pulmonary vascular resistance, measured by right heart catheterisation, from baseline to week 24 in the full analysis set. Pair-wise comparisons between each of the selonsertib groups and the placebo group were made with a stratified Wilcoxon (van Elteren) rank sum test for participants without major protocol deviations who received at least one dose of study drug. This trial is registered with ClinicalTrials.gov, NCT02234141.

FINDINGS

Between Dec 3, 2014, and Nov 13, 2015, 151 patients were enrolled and randomly assigned. Of 150 participants who received selonsertib or placebo, 134 (89%) completed 24 weeks of the randomly assigned treatment; all were on background PAH therapy (138 [92%] on combination therapy). 90 (60%) patients were in functional class II and 60 (40%) in functional class III. Mean baseline pulmonary vascular resistance was 772 (SD 334) dyn·s/cm⁵. Change in pulmonary vascular resistance was 6·0 dyn·s/cm⁵ (SD 28·0; n=31) for placebo, and 35·0 (35·4) dyn·s/cm⁵ (n=35; p=0·21 vs placebo) for 2 mg selonsertib, -28·0 (30·2) dyn·s/cm⁵ (n=34; p=0·27 vs placebo) for 6 mg selonsertib, and -21·0 (37·9) dyn·s/cm⁵ (n=36; p=0·60 vs placebo) for 18 mg selonsertib. The most frequent adverse events were headache (17 [15%]), abnormal dreams (eight [7%]), nausea (seven [6%]), and diarrhoea (seven [6%]) in the selonsertib groups, and headache (six [16%]), nausea (five [14%]), and diarrhoea (two [5%]) in the placebo group. Serious adverse events occurred in 23 (20%) of 113 selonsertib-treated patients and seven (19%) of 37 patients who received placebo.

INTERPRETATION

Selonsertib once daily for 24 weeks did not lead to a significant reduction in pulmonary vascular resistance or to clinical improvement in patients with PAH, but appeared to be safe and well tolerated. Although these data do not support the clinical use of selonsertib in PAH, further study of the potential of targeting the ASK1-p38 pathway in PAH is warranted.

FUNDING

Gilead Sciences.

Switching to riociguat versus maintenance therapy with phosphodiesterase-5 inhibitors in patients with pulmonary arterial hypertension (REPLACE): a multicentre, open-label, randomised controlled trial

BACKGROUND

Riociguat and phosphodiesterase-5 inhibitors (PDE5i), approved for the treatment of pulmonary arterial hypertension (PAH), act on the same pathway via different mechanisms. Riociguat might be an alternative option for patients with PAH who do not respond sufficiently to treatment with PDE5i, but comparisons of the potential benefits of riociguat and PDE5i in these patients are needed. The aim of this trial was to assess the effects of switching to riociguat from PDE5i therapy versus continued PDE5i therapy in patients with PAH at intermediate risk of 1-year mortality.

METHODS

Riociguat rEplacing PDE5i therapy evaLuated Against Continued PDE5i thErapy (REPLACE) was an open-label, randomised controlled trial in 81 hospital-based pulmonary hypertension centres in 22 countries. The study enrolled patients aged 18-75 years with symptomatic PAH at intermediate risk of 1-year mortality (based on the European Society for Cardiology-European Respiratory Society guideline thresholds for WHO functional class and 6-min walk distance [6MWD]) who were receiving treatment with a PDE5i with or without an endothelin receptor antagonist for at least 6 weeks before randomisation. Patients were excluded if they had been previously treated with riociguat, had used prostacyclin analogues or prostacyclin receptor agonists within 30 days before randomisation, had clinically significant restrictive or obstructive parenchymal lung disease, or had left heart disease. Patients were randomly assigned (1:1) to remain on PDE5i treatment (oral sildenafil [≥60 mg per day] or oral tadalafil [20-40 mg per day]; the PDE5i group) or to switch to oral riociguat (up to 2·5 mg three times per day; the riociguat group), using an interactive voice and web response system, stratified by cause of PAH. The primary endpoint was clinical improvement by week 24, defined as an absence of clinical worsening and prespecified improvements in at least two of three variables (6MWD, WHO functional class, and N-terminal prohormone of brain natriuretic peptide), analysed using last observation carried forward in all randomly assigned patients with observed values at baseline and week 24 who received at least one dose of study medication (the full analysis set). Secondary endpoints included clinical worsening events. The trial has been completed and is registered with ClinicalTrials.gov, NCT02891850.

FINDINGS

Between Jan 11, 2017, and July 31, 2019, 293 patients were screened, of which 226 patients were randomly assigned to the riociguat group (n=111) or to the PDE5i group (n=115). 211 patients completed the study and 14 patients discontinued (seven in each group). One patient assigned to the PDE5i group did not receive treatment, so 225 patients were included in the safety analysis, and one further patient in the PDE5i group had missing components of the composite primary endpoint at baseline, so 224 patients were included in the full analysis set. The primary endpoint was met by 45 (41%) of 111 patients in the riociguat group and 23 (20%) of 113 patients in the PDE5i group; odds ratio [OR] 2·78 (95% CI 1·53-5·06; p=0·0007). Clinical worsening events occurred in one (1%) of 111 patients in the riociguat group (hospitalisation due to worsening PAH) and 10 (9%) of 114 patients in the PDE5i group (hospitalisation due to worsening PAH [n=9]; disease progression [n=1]; OR 0·10 [0·01-0·73]; p=0·0047). The most frequently occurring adverse events were hypotension (15 [14%]), headache (14 [13%]), and dyspepsia (10 [9%]) in the riociguat group, and headache (eight [7%]), cough (seven [6%]), and upper respiratory tract infection (seven [6%]) in the PDE5i group. Serious adverse events were reported in eight (7%) of 111 patients in the riociguat group and 19 (17%) of 114 patients in the PDE5i group. During the study, four patients died in the PDE5i group, one of them during the safety follow-up period.

INTERPRETATION

Switching to riociguat from PDE5i treatment, both of which act via the nitric oxide-soluble guanylate cyclase-cyclic guanosine monophosphate pathway, could be a strategic option for treatment escalation in patients with PAH at intermediate risk of 1-year mortality.

FUNDING

Bayer AG, Merck Sharp & Dohme.

Safety and Efficacy of B-Cell Depletion with Rituximab for the Treatment of Systemic Sclerosis-associated Pulmonary Arterial Hypertension: A Multicenter, Double-Blind, Randomized, Placebo-controlled Trial

Rationale: Systemic sclerosis (SSc)-pulmonary arterial hypertension (PAH) is one of the most prevalent and deadly forms of PAH. B cells may contribute to SSc pathogenesis. Objectives: We investigated the safety and efficacy of B-cell depletion for SSc-PAH. Methods: In an NIH-sponsored, multicenter, double-blinded, randomized, placebo-controlled, proof-of-concept trial, 57 patients with SSc-PAH on stable-dose standard medical therapy received two infusions of 1,000 mg rituximab or placebo administered 2 weeks apart. The primary outcome measure was the change in 6-minute-walk distance (6MWD) at 24 weeks. Secondary endpoints included safety and invasive hemodynamics. We applied a machine learning approach to predict drug responsiveness. Measurements and Main Results: We randomized 57 subjects from 2010 to 2018. In the primary analysis, using data through Week 24, the adjusted mean change in 6MWD at 24 weeks favored the treatment arm but did not reach statistical significance (23.6 ± 11.1 m vs. 0.5 ± 9.7 m; P = 0.12). Although a negative study, when data through Week 48 were also considered, the estimated change in 6MWD at Week 24 was 25.5 ± 8.8 m for rituximab and 0.4 ± 7.4 m for placebo (P = 0.03). Rituximab treatment appeared to be safe and well tolerated. Low levels of RF (rheumatoid factor), IL-12, and IL-17 were sensitive and specific as favorable predictors of a rituximab response as measured by an improved 6MWD (receiver operating characteristic area under the curve, 0.88-0.95). Conclusions: B-cell depletion therapy is a potentially effective and safe adjuvant treatment for SSc-PAH. Future studies in these patients can confirm whether the identified biomarkers predict rituximab responsiveness. Clinical trial registered with www.clinicaltrails.gov (NCT01086540).

Direct oral anticoagulant therapy in patients with morbid obesity after intermediate- or high-risk pulmonary emboli

There is little reported on the efficacy and safety of direct oral anticoagulants (DOACs) in morbid obesity after venous thromboembolism (VTE). In this observational study, patients were followed up after intermediate- or high-risk pulmonary embolism (PE) at the University of Rochester Pulmonary Hypertension Clinic 2-4 months after the initial event. All patients had echocardiography and V/Q imaging regardless of symptoms. Outcomes of interest were the rates of recurrent VTE, thrombus resolution and development of chronic thromboembolic pulmonary hypertension (CTEPH) in patients with morbid obesity treated with a DOAC compared to treatment with vitamin K antagonists and to non-morbidly obese patients after PE. Using the electronic medical record, recurrent events were assessed up to 12 months after the event. 107 patients (body mass index (BMI)>40 kg·m^-2, n=32; BMI 30-39.9 kg·m^-2, n=39; BMI<30 kg·m^-2, n=36) attended follow-up appointments after treatment for PE. A DOAC was used in 70 patients (BMI>40 kg·m^-2, n=19; BMI 30-39.9 kg·m^-2, n=27; BMI<30 kg·m^-2, n=24). There were no recurrent events within the first 12 months of initial diagnosis based on symptoms and imaging in any patient. There was no difference in rate of residual unmatched perfusion defect with DOACs or conventional anticoagulation (49% versus 49%). This finding remained in the subset of morbidly obese patients (47% versus 50%). For the overall cohort, there was no difference in the rate of CTEPH development based on anticoagulation with a DOAC (5% versus 8% with warfarin). There were no major bleeding complications with a DOAC. DOAC therapy appears to be effective and safe in morbid obesity even after intermediate- or high-risk PE. ​.

Chronic therapeutic anticoagulation is associated with decreased thrombotic complications in SARS-CoV-2 infection

BACKGROUND

Thrombotic disease complicates severe SARS-CoV-2 infection and is associated with increased morbidity and mortality. Various anticoagulation strategies have been evaluated in hospitalized patients to prevent complications. The impact of chronic anticoagulation before SARS-CoV-2 infection on the risk for subsequent thrombosis has not been systematically studied.

METHODS

This was a retrospective single-center study. All patients with positive SARS-CoV-2 PCR testing from March 13, 2020, through May 6, 2020, at the University of Rochester Medical Center were identified. We included all patients receiving therapeutic anticoagulation for at least 1 month before COVID diagnosis. We documented the rate of thrombotic complications, type of anticoagulation, bleeding complications, and mortality.

RESULTS

A total of 107 SARS-CoV2-infected patients were chronically anticoagulated before SARS-CoV-2 testing with a median age of 78. Of those, 42 required hospital admission, with 17 requiring intensive care. No patients, inpatient or outpatient, were diagnosed with a new symptomatic thrombotic complication. Three patients had minor bleeding in the hospital. Thirteen (12%) patients died (69% male).

CONCLUSION

Our uncontrolled findings suggest that chronic anticoagulation at the time of infection may protect against thrombotic complications and decrease disease severity.

Heart rate monitoring improves clinical assessment during 6-min walk

Right ventricular (RV) function is a predictor of outcomes in pulmonary arterial hypertension (PAH). The 6-min walk test (6MWT) is likely an indirect measure of RV function during exercise, but changes in absolute walk distance can also be influenced by factors like effort and musculoskeletal disease. Paired 6MWT with continuous electrocardiogram monitoring was performed in stable PAH patients, patients adding PAH therapies, and healthy controls. Heart rate expenditure (HRE) was calculated (integrating pulse during 6MWT) and then divided by walk distance (HRE/d). We also evaluated changes in peak heart rate, time above age-adjusted maximum predicted heart rate, and heart rate at 6 min. HRE/d was compared to invasive hemodynamic measures in patients who had right heart catheterization performed within seven days, WHO functional class assessment, and Emphasis 10 questionnaire. We measured two 6MWT in 15 stable PAH patients, 13 treatment intensification patients, and 8 healthy controls. HRE/d was reproducible in the stable PAH group (median difference, -0.79%), while it decreased (median difference, 23%, p = 0.0001) after adding vasodilator therapy. In 11 patients with right heart catheterization, HRE/d correlated strongly with stroke volume, r = -0.72, p = 0.01. Peak heart rate decreased after adding vasodilator therapy. HRE/d also correlated with WHO functional class and Emphasis 10 score. Continuous heart rate monitoring during 6MWT provides valuable physiologic data accounting for effort. HRE/d appears to enhance test reproducibility in stable patients while detecting change after adding therapy as compared to walk distance alone.

Clinical trial design in phase 2 and 3 trials for pulmonary hypertension

This article on clinical trial design incorporates the broad experience of members of the Pulmonary Vascular Research Institute's (PVRI) Innovative Drug Development Initiative (IDDI) as an open debate platform for academia, the pharmaceutical industry and regulatory experts surrounding the future design of clinical trials in pulmonary hypertension. It is increasingly clear that the design of phase 2 and 3 trials in pulmonary hypertension will have to diversify from the traditional randomised double-blind design, given the anticipated need to trial novel therapeutic approaches in the immediate future. This article reviews a wide range of differing approaches and places these into context within the field of pulmonary hypertension.

Tumor Necrosis Factor Induces Obliterative Pulmonary Vascular Disease in a Novel Model of Connective Tissue Disease-Associated Pulmonary Arterial Hypertension

OBJECTIVE

Connective tissue disease (CTD)-associated pulmonary arterial hypertension (PAH) is the second most common etiology of PAH and carries a poor prognosis. Recently, it has been shown that female human tumor necrosis factor (TNF)-transgenic (Tg) mice die of cardiopulmonary disease by 6 months of age. This study was undertaken to characterize this pathophysiology and assess its potential as a novel model of CTD-PAH.

METHODS

Histologic analysis was performed on TNF-Tg and wild-type (WT) mice to characterize pulmonary vascular and right ventricular (RV) pathology (n = 40 [4-5 mice per group per time point]). Mice underwent right-sided heart catheterization (n = 29) and micro-computed tomographic angiography (n = 8) to assess vascular disease. Bone marrow chimeric mice (n = 12), and anti-TNF-treated mice versus placebo-treated mice (n = 12), were assessed. RNA sequencing was performed on mouse lung tissue (n = 6).

RESULTS

TNF-Tg mice displayed a pulmonary vasculopathy marked by collagen deposition (P < 0.001) and vascular occlusion (P < 0.001) with associated RV hypertrophy (P < 0.001) and severely increased RV systolic pressure (mean ± SD 75.1 ± 19.3 mm Hg versus 26.7 ± 1.7 mm Hg in WT animals; P < 0.0001). TNF-Tg mice had increased α-smooth muscle actin (α-SMA) staining, which corresponded to proliferation and loss of von Willebrand factor (vWF)-positive endothelial cells (P < 0.01). There was an increase in α-SMA-positive, vWF-positive cells (P < 0.01), implicating endothelial-mesenchymal transition. Bone marrow chimera experiments revealed that mesenchymal but not bone marrow-derived cells are necessary to drive this process. Treatment with anti-TNF therapy halted the progression of disease. This pathology closely mimics human CTD-PAH, in which patient lungs demonstrate increased TNF signaling and significant similarities in genomic pathway dysregulation.

CONCLUSION

The TNF-Tg mouse represents a novel model of CTD-PAH, recapitulates key disease features, and can serve as a valuable tool for discovery and assessment of therapeutics.

Clinical and imaging outcomes after intermediate- or high-risk pulmonary embolus

Long-term outcomes after acute pulmonary embolism vary from complete resolution to chronic thromboembolic pulmonary hypertension (CTEPH). Guidelines after acute pulmonary embolism are generally limited to anticoagulation duration. We assessed patients with estimated prognosis >1 year in our pulmonary hypertension clinic 2–4 months after treatment for intermediate- or high-risk acute pulmonary embolism. At follow-up, ventilation–perfusion scan and echocardiogram were offered. The aim of this study was to assess for recurrent symptomatic disease, residual imaging defects or right ventricular dysfunction, and functional disability after acute management of pulmonary embolism. After treatment for acute intermediate- or high-risk pulmonary embolism, 104 patients followed up in pulmonary hypertension clinic. Of those, 55% of patients had self-reported limitation in activity. No patients had symptomatic recurrence of pulmonary embolism. Forty-eight percent of patients had residual perfusion defects on perfusion imaging, while 91% of patients had either normal or only mildly enlarged right ventricles. We identified heart failure preserved ejection fraction, iron deficiency, and obstructive sleep apnea as significant contributors to breathlessness. Treatment of these conditions was associated with improvement. Surprisingly, we diagnosed CTEPH in nine patients; for some, chronic thrombus may already have been present at the time of index evaluation. Our findings suggest that follow-up in a dedicated pulmonary hypertension clinic 2–4 months after acute intermediate- or high-risk pulmonary embolism may add value to patient care. We identified treatable comorbidities that could be contributing to post-pulmonary embolism syndrome as well as CTEPH.

Combination Therapy with Oral Treprostinil for Pulmonary Arterial Hypertension. A Double-Blind Placebo-controlled Clinical Trial

Rationale: Oral treprostinil improves exercise capacity in patients with pulmonary arterial hypertension (PAH), but the effect on clinical outcomes was unknown.

Objectives: To evaluate the effect of oral treprostinil compared with placebo on time to first adjudicated clinical worsening event in participants with PAH who recently began approved oral monotherapy.

Methods: In this event-driven, double-blind study, we randomly allocated 690 participants (1:1 ratio) with PAH to receive placebo or oral treprostinil extended-release tablets three times daily. Eligible participants were using approved oral monotherapy for over 30 days before randomization and had a 6-minute-walk distance 150 m or greater. The primary endpoint was the time to first adjudicated clinical worsening event: death; hospitalization due to worsening PAH; initiation of inhaled or parenteral prostacyclin therapy; disease progression; or unsatisfactory long-term clinical response.

Measurements and Main Results: Clinical worsening occurred in 26% of the oral treprostinil group compared with 36% of placebo participants (hazard ratio, 0.74; 95% confidence interval, 0.56–0.97; P = 0.028). Key measures of disease status, including functional class, Borg dyspnea score, and N-terminal pro–brain natriuretic peptide, all favored oral treprostinil treatment at Week 24 and beyond. A noninvasive risk stratification analysis demonstrated that oral treprostinil–assigned participants had a substantially higher mortality risk at baseline but achieved a lower risk profile from Study Weeks 12–60. The most common adverse events in the oral treprostinil group were headache, diarrhea, flushing, nausea, and vomiting.

Conclusions: In participants with PAH, addition of oral treprostinil to approved oral monotherapy reduced the risk of clinical worsening.

Clinical trial registered with www.clinicaltrials.gov (NCT01560624).

P0229APPLICATION OF A RISK MITIGATION STRATEGY TO PREVENT EXCESS CARDIOVASCULAR RISK IN PULMONARY HYPERTENSION: LARIAT STUDY

Background and Aims

Bardoxolone Methyl Evaluation in Patients with Chronic Kidney Disease and Type 2 Diabetes (BEACON) was a multinational, randomized, double-blind, placebo-controlled Phase 3 trial that enrolled patients with type 2 diabetes (T2D) and stage 4 CKD. The BEACON trial was terminated due to a significant increase in the risk of heart failure occurring within the first four weeks of treatment with bardoxolone methyl. Post-hoc analyses identified a history of heart failure and elevated baseline serum concentrations of B-type natriuretic peptide (BNP) as risk factors for these events. A subsequent study, LARIAT (NCT02316821), was designed to evaluate the efficacy and safety of bardoxolone methyl in the treatment of patients with pulmonary arterial hypertension (PAH). Progressive right heart failure is the cause of death for most PAH patients, and PAH patients are at high risk for decompensated right heart failure. LARIAT was designed to mitigate the risk for heart failure, and here we present cardiovascular safety data from this trial.

Method

The LARIAT study was a 16-week double-blind, randomized, placebo-controlled, dose-ranging study that enrolled 208 patients with a confirmed diagnosis of PAH, most of whom had Group 1 Pulmonary Arterial Hypertension and were taking stable doses of at least one approved PAH therapy. Patients were randomized 3:1 to receive bardoxolone methyl or placebo at a starting dose of 2.5 mg, and subsequent doses of 5, 10, or 20mg. In addition to the dose-titration scheme, the initial protocol excluded patients with BNP &gt; 200 pg/mL (later amended to 400 pg/mL), acutely decompensated heart failure in the previous 30 days, or eGFR &lt; 45 mL/min/1.73 m2 at baseline. BNP and NT-proBNP were assessed serially throughout the study. In addition, 24-hour ambulatory blood pressure (ABPM) was monitored in a subset of the patients at baseline, Week 4, and Week 16.

Results

One fluid overload SAE was reported in a placebo patient but not in any bardoxolone methyl patients. Overall, only 2 (1.7%) bardoxolone methyl patients reported cardiovascular SAEs, neither of which were attributed to study drug. Moreover, there were no statistically significant increases in 24-hour ABPM blood pressure, weight, or NT-Pro BNP and BNP levels in bardoxolone methyl-treated patients. Thus, treatment with bardoxolone methyl did not appear to be associated with an increased risk for heart failure hospitalizations or fluid overload adverse events in the LARIAT study.

Conclusion

Despite the real risk for fluid retention and acutely decompensated heart failure in PAH patients, use of BNP &lt; 400 pg/ml and HF history can be used to safely select patients with PAH to receive bardoxolone methyl. There was no increased risk of heart failure or other signs of overt fluid overload; we did not observe subclinical measures of fluid retention (increases in blood pressure or weight). These data support the use of a risk-mitigation strategy in the continued development of bardoxolone methyl for patients at risk for decompensated heart failure.

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 once-daily 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.

Funded by Gilead Sciences, Inc. and GlaxoSmithKline; AMBITION ClinicalTrials.gov number, NCT01178073.

Supplementary information

Supplementary information accompanies this paper at 10.1186/s12931-019-1180-1.

Combination therapy improves vascular volume in female rats with pulmonary hypertension

Pulmonary arterial hypertension (PAH) is a female predominant disease in which progressive vascular remodeling and vasoconstriction result in right ventricular (RV) failure and death. Most PAH patients utilize multiple therapies. In contrast, the majority of preclinical therapeutic studies are performed in male rats with a single novel drug often markedly reversing disease in the model. We sought to differentiate single drug therapy from combination therapy in female rats with severe disease. One week after left pneumonectomy, we induced PH in young female Sprague-Dawley rats with an injection of monocrotaline (45 mg/kg). Female rats were then randomized to receive combination therapy (ambrisentan plus tadalafil), ambrisentan monotherapy, tadalafil monotherapy, or vehicle. We measured RV size and function on two serial echocardiograms during the development of disease. We measured RV systolic pressure (RVSP) invasively at day 28 after monocrotaline before analyzing the vascular volume with microcomputed tomography (microCT) of the right middle lobe. RVSP was significantly lower in female rats treated with combination therapy, and combination therapy resulted in increased small vessel volume density measured by microCT compared with untreated rats. Combination-treated rats had the smallest RV end-diastolic diameter on echocardiogram as compared with the other groups. In summary, we report a female model of pulmonary hypertension that can distinguish between one and two drug therapies; this model may facilitate better preclinical drug testing for novel compounds.

EXPRESS: Long term study of oral treprostinil to treat pulmonary arterial hypertension: dosing, tolerability, and pharmacokinetics

Oral treprostinil may be an option for low- and intermediate-risk patients with pulmonary arterial hypertension, a rare lung vascular disease. This open-label extension study collected data on participants who completed previously reported, placebo-controlled oral treprostinil studies. Eligible participants had completed the prospective parent studies and took increasing doses of oral treprostinil twice daily; some later transitioned to three times daily dosing. Investigators measured 6-minute walk distance at Month 12 as the sole efficacy measure but collected adverse events throughout the study. A single center measured pharmacokinetics in 13 subjects who changed dosing from twice daily to three times daily. Eight hundred and ninety-four participants enrolled and 71% completed one year of therapy, with a median total daily dose of 7 mg and a median 6-minute walk distance increase of 22 m (interquartile range, −14 to 67 m). Subjects achieving higher doses had larger increases in 6-minute walk distance; 42% of participants completed three years of therapy. Adverse events were typical for prostacyclin class therapy, but prostacyclin-type adverse events may have been better tolerated with three times daily dosing in 105 participants. In 13 participants transitioned to three times daily dosing with pharmacokinetic measurements before and after, trough drug levels were higher with three times daily dosing. Oral treprostinil is associated with modest but durable, dose-responsive effects on exercise tolerance for those who remained on therapy at one year in this prospective, uncontrolled study. Three times daily dosing was associated with higher trough levels and better tolerability. The recently completed Freedom-EV study will provide further insights into the utility of oral treprostinil (https://clinicaltrials.gov/show/NCT01560624 ).

Treatment Patterns and Associated Health Care Costs Before and After Treatment Initiation Among Pulmonary Arterial Hypertension Patients in the United States

BACKGROUND

Despite multiple treatment options, the prognosis of pulmonary arterial hypertension (PAH) remains poor. PAH patients experience a high economic burden due to comorbidities, hospitalizations, and medication costs. Although combination therapy has been shown to reduce hospitalizations, the relationship between treatment, health care utilization, and costs remains unclear.

OBJECTIVE

To provide a characterization of health care utilization and costs in real-world settings by comparing periods before and after initiating PAH-specific treatment.

METHODS

This retrospective study identified PAH patients in the Truven Health MarketScan Commercial and Medicare Supplemental Databases between 2010 and 2014 who initiated treatment with endothelin receptor antagonists (ERAs), phosphodiesterase-5 inhibitors (PDE-5Is), or soluble guanylate cyclase (sGC) stimulators. The index date was the date of the first PAH pharmacy claim. We included patients with ≥ 2 medical claims with diagnoses for PAH (ICD-9-CM: 416.0, 416.8) or PAH-related conditions and continuous enrollment in medical and pharmacy benefits for the 6 months before and after the index date. Treatment patterns were assessed at the drug class level (ERAs, PDE-5Is, sGC stimulators, and prostacyclins) from outpatient pharmacy claims during the 6-month post-index period. All-cause and PAH-related utilization and costs were measured. McNemar's and paired t-tests were used to compare patients' health care resource utilization and costs in the 6-month pre- and posttreatment periods.

RESULTS

A total of 3,908 patients met the selection criteria. The study sample was 63% female with a mean age of 63 ± 15 years. Only 5% of patients began initial combination therapy for PAH, defined as claims for ≥ 2 medication classes within the first 30 days of treatment. Treatment interruption (≥ 30-day gap in days supply) of any PAH-specific medication was observed in 38% of patients. Compared with the 6-month pre-index period, the proportion of patients in the 6-month post-index period with any inpatient admission decreased, 42% versus 30% (P < 0.001). In addition, PAH-related inpatient admissions decreased in the 6-month post-index period from 7% to 3% (P < 0.001). After treatment initiation, patients' nonpharmacy medical costs decreased from $48,200 (SD = $117,686) to $33,962 (SD = $90,294; P < 0.001), mainly attributable to reduced inpatient costs. However, total average medical costs including pharmacy costs remained comparable after treatment initiation (pre-index period = $51,455 vs. post-index period = $53,923; P = 0.213).

CONCLUSIONS

This study found that while patients' PAH-related pharmacy costs increased after treatment initiation, the increase was offset by reduced inpatient utilization; therefore, total health care costs remained constant. While the majority of patients in this study were treated with monotherapy, the recently completed AMBITION study indicated that initial combination therapy with ambrisentan plus tadalafil reduced PAH-related hospitalizations compared with initial monotherapy with either of these agents. Future cost analyses of patients treated with combination therapy will be required to determine the economic effect of initial combination therapy.

DISCLOSURES

This study was sponsored and funded by Gilead Sciences. Ozbay is an employee of Gilead Sciences. At the time that this project and manuscript were developed, Lazarus was an employee of Gilead Sciences and may own stock/stock options. Riehle, Montejano, and Lenhart are employees of Truven Health Analytics, an IBM company, which received funding from Gilead Sciences to conduct this study. Burger and White do research with, and are paid consultants for, Gilead Sciences; they do not own equity and received no personal compensation for the work here. Burger also reports consultancy and advisory board work for Actelion Pharmaceuticals and grants from Gilead Sciences, Actelion Pharmaceuticals, Bayer, and United Therapeutics.

Low dose monocrotaline causes a selective pulmonary vascular lesion in male and female pneumonectomized rats

Purpose/Aim: Low doses (30-80 mg/kg) of monocrotaline are commonly used to create experimental models of pulmonary hypertension in rats. At these doses, monocrotaline causes pulmonary endothelial apoptosis and acute lung injury which ultimately results in pulmonary vascular disease. Higher doses of monocrotaline (300 mg/kg) are known to create severe liver injury, but previous investigations with lower doses have not reported histology in other organs to determine whether the vascular injury with monocrotaline is pulmonary-selective or generalized.

MATERIALS AND METHODS

We therefore sought to determine whether monocrotaline caused extra-pulmonary injury at doses commonly used in pulmonary hypertension studies. We performed left pneumonectomy on young male and female rats before administering 50-60 mg/kg monocrotaline 7 days later. We monitored serum chemistry and urine dipsticks during the first 3 weeks while the animals developed pulmonary hypertension. After 3 weeks, we sacrificed animals and stained the lungs and highly vascular visceral organs (kidney, liver, and spleen) for elastin to evaluate the degree of vascular injury and remodeling.

RESULTS

We did not observe proteinuria or significant transaminitis over the 3 weeks following monocrotaline. As previously published, monocrotaline caused severe pulmonary vascular disease with neointimal lesions and medial hypertrophy. We did not identify significant large or small arterial damage in the kidneys, liver, or spleen. Two external veterinary pathologists did not identify histopathology in the kidneys, liver, or spleen of these rats.

CONCLUSIONS

We conclude that 50-60 mg/kg of monocrotaline causes a selective pulmonary vascular lesion and that male and female rats have little non-pulmonary damage over 3 weeks at these doses of monocrotaline.

Recommendations for the use of oral treprostinil in clinical practice: a Delphi consensus project pulmonary circulation

Oral treprostinil was recently labeled for treatment of pulmonary arterial hypertension. Similar to the period immediately after parenteral treprostinil was approved, there is a significant knowledge gap for practicing physicians who might prescribe oral treprostinil. Despite its oral route of delivery, use of the drug is challenging because of the requirement for careful titration and management of drug-related adverse effects. We aimed to create a consensus document combining available evidence with expert opinion to provide guidance for use of oral treprostinil. Following a methodology commonly used in business and social sciences (the 'Delphi Process'), two investigators from the oral treprostinil (Freedom) studies created a series of statements based on available evidence and the package insert. The set of 'best practice' statements was circulated to nine other Freedom trial investigators. Their comments were incorporated into the document as new line items for further vote and comment. The subsequent document was put to vote line by line (scale of -5 to +5) and a final statement was drafted. Consensus recommendations include initial therapy with 0.125 mg for treatment naÿ patients, three times daily dosing, aggressive use of antidiarrheal medication, and a strong preference for use of the drug in combination with other approved PAH therapies. This process was particularly valuable in providing guidance for the management of adverse events (where essentially no data is available). The Delphi process was useful to codify investigator experience and subsequently develop investigator consensus about practical issues for physicians who may wish to prescribe oral treprostinil.

Transition from parenteral to oral treprostinil in pulmonary arterial hypertension

BACKGROUND

Parenteral prostanoids are effective treatment for pulmonary arterial hypertension, but long-term pump infusion systems have significant delivery-related safety and convenience limitations.

METHODS

Subjects with a favorable risk profile transitioned from parenteral to oral treprostinil using a protocol-driven titration during 5 days of inpatient observation. Baseline and Week 24 assessments included 6-minute walk distance, echocardiogram, right heart catheterization, pharmacokinetics, treatment satisfaction and quality of life. Thirty-three subjects (76% female, mean age 50 years) enrolled; 85% were using subcutaneous treprostinil with a median dose of 57 (range 25 to 111) ng/kg/min. Participants were using background, approved non-prostanoid therapy, including 9 on 2 oral therapies; baseline right atrial pressure and cardiac output were in the normal range. All 33 subjects transitioned to oral treprostinil therapy within 4 weeks, but 2 transitioned back to parenteral drug before Week 24. At Week 24, subjects were taking a median total daily dose of 44 (15 to 75) mg, with 25 of 31 using a 3-times-daily regimen at 7- to 9-hour intervals.

RESULTS

The 6-minute walk distance was preserved (median +17 m [-98 to 95 m]) at its baseline of 446 m. Hemodynamic variables, including pulmonary vascular resistance, were similar at Week 24 except for mixed venous saturation, which dropped from a median of 71% to 68% (p < 0.001). Overall quality of life and treatment satisfaction measures did not change; however, mood-related symptom and treatment convenience subscores improved. Common adverse effects included headache, nausea, flushing and diarrhea.

CONCLUSIONS

Lower risk patients managed on parenteral treprostinil may be candidates for transition to a more convenient, oral form of the drug.

Hepatic Shunting of Eggs and Pulmonary Vascular Remodeling in Bmpr2(+/-) Mice with Schistosomiasis

RATIONALE

Schistosomiasis is a major cause of pulmonary arterial hypertension (PAH). Mutations in the bone morphogenetic protein type-II receptor (BMPR-II) are the commonest genetic cause of PAH.

OBJECTIVES

To determine whether Bmpr2(+/-) mice are more susceptible to schistosomiasis-induced pulmonary vascular remodeling.

METHODS

Wild-type (WT) and Bmpr2(+/-) mice were infected percutaneously with Schistosoma mansoni. At 17 weeks postinfection, right ventricular systolic pressure and liver and lung egg counts were measured. Serum, lung and liver cytokine, pulmonary vascular remodeling, and liver histology were assessed.

MEASUREMENTS AND MAIN RESULTS

By 17 weeks postinfection, there was a significant increase in pulmonary vascular remodeling in infected mice. This was greater in Bmpr2(+/-) mice and was associated with an increase in egg deposition and cytokine expression, which induced pulmonary arterial smooth muscle cell proliferation, in the lungs of these mice. Interestingly, Bmpr2(+/-) mice demonstrated dilatation of the hepatic central vein at baseline and postinfection, compared with WT. Bmpr2(+/-) mice also showed significant dilatation of the liver sinusoids and an increase in inflammatory cells surrounding the central hepatic vein, compared with WT. This is consistent with an increase in the transhepatic passage of eggs.

CONCLUSIONS

This study has shown that levels of BMPR-II expression modify the pulmonary vascular response to chronic schistosomiasis. The likely mechanism involves the increased passage of eggs to the lungs, caused by altered diameter of the hepatic veins and sinusoids in Bmpr2(+/-) mice. Genetically determined differences in the remodeling of hepatic vessels may represent a new risk factor for PAH associated with schistosomiasis.

Initial Use of Ambrisentan plus Tadalafil in Pulmonary Arterial Hypertension

BACKGROUND

Data on the effect of initial combination therapy with ambrisentan and tadalafil on long-term outcomes in patients with pulmonary arterial hypertension are scarce.

METHODS

In this event-driven, double-blind study, we randomly assigned, in a 2:1:1 ratio, participants with World Health Organization functional class II or III symptoms of pulmonary arterial hypertension who had not previously received treatment to receive initial combination therapy with 10 mg of ambrisentan plus 40 mg of tadalafil (combination-therapy group), 10 mg of ambrisentan plus placebo (ambrisentan-monotherapy group), or 40 mg of tadalafil plus placebo (tadalafil-monotherapy group), all administered once daily. The primary end point in a time-to-event analysis was the first event of clinical failure, which was defined as the first occurrence of a composite of death, hospitalization for worsening pulmonary arterial hypertension, disease progression, or unsatisfactory long-term clinical response.

RESULTS

The primary analysis included 500 participants; 253 were assigned to the combination-therapy group, 126 to the ambrisentan-monotherapy group, and 121 to the tadalafil-monotherapy group. A primary end-point event occurred in 18%, 34%, and 28% of the participants in these groups, respectively, and in 31% of the pooled-monotherapy group (the two monotherapy groups combined). The hazard ratio for the primary end point in the combination-therapy group versus the pooled-monotherapy group was 0.50 (95% confidence interval [CI], 0.35 to 0.72; P<0.001). At week 24, the combination-therapy group had greater reductions from baseline in N-terminal pro-brain natriuretic peptide levels than did the pooled-monotherapy group (mean change, -67.2% vs. -50.4%; P<0.001), as well as a higher percentage of patients with a satisfactory clinical response (39% vs. 29%; odds ratio, 1.56 [95% CI, 1.05 to 2.32]; P=0.03) and a greater improvement in the 6-minute walk distance (median change from baseline, 48.98 m vs. 23.80 m; P<0.001). The adverse events that occurred more frequently in the combination-therapy group than in either monotherapy group included peripheral edema, headache, nasal congestion, and anemia.

CONCLUSIONS

Among participants with pulmonary arterial hypertension who had not received previous treatment, initial combination therapy with ambrisentan and tadalafil resulted in a significantly lower risk of clinical-failure events than the risk with ambrisentan or tadalafil monotherapy. (Funded by Gilead Sciences and GlaxoSmithKline; AMBITION ClinicalTrials.gov number, NCT01178073.).

Customized Internal Reference Controls for Improved Assessment of Circulating MicroRNAs in Disease

Background

Altered levels of circulating extracellular miRNA in plasma and serum have shown promise as non-invasive biomarkers of disease. However, unlike the assessment of cellular miRNA levels for which there are accepted housekeeping genes, analogous reference controls for normalization of circulating miRNA are lacking. Here, we provide an approach to identify and validate circulating miRNA reference controls on a de novo basis, and demonstrate the advantages of these customized internal controls in different disease settings. Importantly, these internal controls overcome key limitations of external spike-in controls.

Methods

Using a global RT-qPCR screen of 1066 miRNAs in plasma from pulmonary hypertension patients (PAH) and healthy subjects as a case example, we identified a large pool of initial candidate miRNAs that were systematically ranked according to their plasma level stability using a predefined algorithm. The performance of the top candidates was validated against multiple comparators, and in a second independent cohort of PAH and control subjects. The broader utility of this approach was demonstrated in a completely different disease setting with 372 miRNAs screened in plasma from septic shock patients and healthy controls.

Results

Normalization of data with specific internal reference controls significantly reduced the overall variation in circulating miRNA levels between subjects (relative to raw data), provided a more balanced distribution of up- and down-regulated miRNAs, replicated the results obtained by the benchmark geometric averaging of all detected miRNAs, and outperformed the commonly used external spike-in strategy.

Conclusions

We demonstrate the feasibility of identifying circulating reference controls that can reduce extraneous technical variations, and improve the assessment of disease-related changes in plasma miRNA levels. This study provides a novel conceptual framework that addresses a critical and previously unmet need if circulating miRNAs are to advance as reliable diagnostic tools in medicine.