Use of outcome measures in pulmonary hypertension clinical trials

Safety, Feasibility, and Utility of Digital Mobile Six-Minute Walk Testing in Pulmonary Arterial Hypertension: The DynAMITE Study

Rationale

Pulmonary arterial hypertension (PAH) is a life-threatening progressive cardiopulmonary disease associated with high morbidity and mortality. Changes in the six-minute walk test (6MWT) provide prognostic information and help guide treatment decisions for PAH. However, since 6MWT requires in-clinic visits, clinical interventions to address disease progression may be delayed. Wearable technologies could reduce this delay by allowing the performance of 6MWT in the community and delivering data to clinicians remotely.

Objectives

To perform a pilot study to determine the safety and feasibility of performing 6MWT in PAH outpatients using a wearable app-based tool.

Methods

PAH patients recruited at Stanford University were provided an Apple Watch with an app to perform daily, self-administered 6MWT over 12 weeks. Bland-Altman plots and correlations were used to assess the agreement and reliability of in-clinic vs. app-based 6MWT data at the beginning and end of the 12-week trial.

Measurements and Main Results

From 55 PAH participants, we collected 3,139 app-recorded walks during 979.7 patient-weeks of exposure. On average, participants performed 3±2.3 weekly walks. No serious adverse events were reported. App-derived walk distance was highly correlated ( r ≥ 0.9) to the baseline in-clinic 6MWD and showed excellent reliability (ICC=0.9). Correlation and agreement were significantly lower at the 12-week follow-up visit. App-derived metrics beyond 6MWD showed promising associations with disease status.

Conclusions

App-based outpatient 6MWT is feasible, safe, reasonably accurate, likely clinically relevant, and reliable in PAH patients but long-term measurement stability may be a concern. App-derived digital measures beyond distance show promise for future applications.

Clinical Utility of Patient-Reported Outcome Instruments in the Management of Pulmonary Hypertension: A Systematic Review

BACKGROUND

Despite the greater sensitivity and specificity of disease-specific patient-reported outcome measures (PROM) to detect clinical change, only recently have such instruments been developed for pulmonary hypertension (PH), specifically pulmonary arterial hypertension (PAH) and chronic thromboembolic disease (CTEPH). Although these valuable tools are now being incorporated into clinical studies of PH, they have not yet reached widespread integration into routine clinical care.

OBJECTIVES

In this systematic review, the authors assess the psychometric properties of PROM developed for PH, compare PROM with other clinical outcomes in PH, and address the utility of PROM in clinical care.

METHODS

The authors performed a systematic search of papers published between January 1, 2006, and October 1, 2022, using the MEDLINE database to identify PROM developed and validated for PH. The identified PROM were found to have been developed only in groups with PAH and CTEPH. The authors evaluated the identified instruments according to established psychometric criteria. An additional search was performed to identify randomized controlled trials (RCTs) utilizing these PROM for comparison with clinical outcomes.

RESULTS

From 527 papers retrieved, a total of 35 PROM were identified. Of these, 5 disease-specific instruments were included in the final analysis. While both CAMPHOR (Cambridge Pulmonary Hypertension Outcome Review) and emPHasis-10 performed well in patients with PAH and CTEPH with regard to their psychometric properties, emPHasis-10 demonstrated superior feasibility for use in clinical practice due to its concise format. The Pulmonary Arterial Hypertension-Symptoms and Impacts Questionnaire performed well in the authors' analysis, though additional data is needed regarding interpretability and feasibility.

CONCLUSIONS

EmPHasis-10 demonstrated strong psychometric properties and the greatest feasibility for clinical use. Further study assessing the integration of PROM into routine clinical care for PH is needed.

The sine transform is the sine qua non of the pulmonary and systemic pressure relationship

Assessment of therapeutic interventions in patients with pulmonary arterial hypertension (PAH) suffers from several commonly encountered limitations: (1) patient studies are often too small and short-term to provide definitive conclusions, (2) there is a lack of a universal set of metrics to adequately assess therapy and (3) while clinical treatments focus on management of symptoms, there remain many cases of early loss of life in a seemingly arbitrary distribution. Here we provide a unified approach to assess right and left pressure relationships in PAH and pulmonary hypertension (PH) patients by developing linear models informed by the observation of Suga and Sugawa that pressure generation in the ventricle (right or left) approximately follows a single lobe of a sinusoid. We sought to identify a set of cardiovascular variables that either linearly or via a sine transformation related to systolic pulmonary arterial pressure (PAPs) and systemic systolic blood pressure (SBP). Importantly, both right and left cardiovascular variables are included in each linear model. Using non-invasively obtained cardiovascular magnetic resonance (CMR) image metrics the approach was successfully applied to model PAPs in PAH patients with an r2 of 0.89 (p < 0.05) and SBP with an r2 of 0.74 (p < 0.05). Further, the approach clarified the relationships that exist between PAPs and SBP separately for PAH and PH patients, and these relationships were used to distinguish PAH vs. PH patients with good accuracy (68%, p < 0.05). An important feature of the linear models is that they demonstrate that right and left ventricular conditions interact to generate PAPs and SBP in PAH patients, even in the absence of left-sided disease. The models predicted a theoretical right ventricular pulsatile reserve that in PAH patients was shown to be predictive of the 6 min walk distance (r2 = 0.45, p < 0.05). The linear models indicate a physically plausible mode of interaction between right and left ventricles and provides a means of assessing right and left cardiac status as they relate to PAPs and SBP. The linear models have potential to allow assessment of the detailed physiologic effects of therapy in PAH and PH patients and may thus permit cross-over of knowledge between PH and PAH clinical trials.

Prognostic biomarkers in pediatric pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a progressive life-threatening disease of the pulmonary vasculature. Despite the introduction of targeted therapies, prognosis remains poor. In pediatric PAH, reliable prognostic biomarkers are needed to inform clinicians on disease progression and risk of mortality, in order to be able to assess the need for escalation of medical therapy, consider surgical options such as Pott's shunt and listing for (heart)-lung transplantation. This review provides an overview of prognostic biomarkers that are considered to carry potential for the clinical management of pediatric PAH. These include conventional physiological biomarkers [resting heart rate, heart rate variability (HRV), a child's growth], biomarkers of functional status [World Health Organization functional class, 6-minute walk distance (6MWD), parameters derived from cardiopulmonary exercise testing (CPET), daily physical activity level], electrocardiographic biomarkers, circulating serum biomarkers (natriuretic peptides, uric acid, neurohormones, inflammatory markers, and novel circulating biomarkers), and multiple hemodynamic biomarkers and imaging biomarkers [echocardiography and cardiac magnetic resonance (CMR)]. In recent years, many potential prognostic biomarkers have become available for the management of PAH in children. As the available prognostic biomarkers reflect different aspects of the disease process and functional implications, a multi-marker approach appears the most useful for guiding therapy decisions and improve outcome in pediatric PAH.

How should a physician approach the pharmacological management of chronic thromboembolic pulmonary hypertension?

INTRODUCTION

Chronic thromboembolic pulmonary hypertension (CTEPH) is characterized by the presence of organized thromboembolic material and proliferative fibrous intima occluding varying degrees of the pulmonary arteries, and is also accompanied by small vessel vasculopathy in occluded and non-occluded pulmonary vasculature. The similarity in hemodynamics and pathophysiology between CTEPH and group 1 pulmonary arterial hypertension provides the rationale for clinical use of pulmonary arterial hypertension (PAH)-specific therapy.

AREAS COVERED

The authors present the current knowledge concerning the updated therapeutic strategies in CTEPH, and try to illustrate the established and uncertain role of PAH-specific therapy and anticoagulation therapy. The real-world observational registries and landmark randomized controlled trials of PAH-specific drugs in CTEPH are emphasized in the manuscript.

EXPERT OPINION

Despite surgical and interventional therapies, which could provide effective and potential curable treatments, medical therapies are still the substantial and irreplaceable option for patients with CTEPH. More and more PAH-specific drugs have demonstrated favorable efficacy and safety profiles in patients with CTEPH. Additionally, anticoagulation therapy is also a substantial medical treatment in all CTEPH patients without contradiction. However, the benefit-to-risk balance in life-long anticoagulation and whether more individualized anticoagulation strategies are needed warrants further investigation.

The Role of Noninvasive Endpoints in Predicting Long-Term Outcomes in Pulmonary Arterial Hypertension

Background

Until recently, many clinical trials in patients with pulmonary arterial hypertension (PAH) evaluated exercise capacity with 6-minute walk distance (6MWD) as the primary endpoint. Common secondary endpoints include PAH functional class (FC), which assesses symptoms, and either brain natriuretic peptide (BNP) or the inactive N-terminal cleavage product of its prohormone (NT-proBNP), which assesses cardiac function.

Objective

Examine the relationships among 6MWD, FC, and BNP/NT-proBNP measured at baseline or follow-up with long-term outcomes in PAH studies.

Methods

Relevant literature from January 1990 to April 2018 were obtained by searching PubMed, Embase, and Cochrane. Articles in English reporting on associations between 6MWD, FC, or BNP/NT-proBNP and outcomes in PAH were identified. Each endpoint was evaluated individually. Prespecified inclusion and exclusion criteria were applied at level 1 (titles/abstracts) and level 2 (full-text review).

Results

The database search yielded 836 unique records; 65 full-text articles were reviewed. Twenty-five studies were eligible for inclusion. Findings supported the importance of measuring PAH noninvasive endpoints in predicting long-term outcomes. Patients with shorter or decreased 6MWD, poor (III/IV) or declining FC (e.g., from II to III), or elevated or increasing BNP/NT-proBNP had a higher risk of death and costly events (e.g., hospitalization, lung transplant). FC also predicted health care resource utilization and costs. Collectively, these endpoints establish risk groups that predict likelihood of complications from PAH or death.

Conclusion

Assessment of 6MWD, FC, and BNP/NT-proBNP provides low-cost, efficient, and noninvasive means of predicting long-term health and economic outcomes in patients with PAH.

Clinical trial design and new therapies for pulmonary arterial hypertension

Until 20 years ago the treatment of pulmonary arterial hypertension (PAH) was based on case reports and small series, and was largely ineffectual. As a deeper understanding of the pathogenesis and pathophysiology of PAH evolved over the subsequent two decades, coupled with epidemiological studies defining the clinical and demographic characteristics of the condition, a renewed interest in treatment development emerged through collaborations between international experts, industry and regulatory agencies. These efforts led to the performance of robust, high-quality clinical trials of novel therapies that targeted putative pathogenic pathways, leading to the approval of more than 10 novel therapies that have beneficially impacted both the quality and duration of life. However, our understanding of PAH remains incomplete and there is no cure. Accordingly, efforts are now focused on identifying novel pathogenic pathways that may be targeted, and applying more rigorous clinical trial designs to better define the efficacy of these new potential treatments and their role in the management scheme. This article, prepared by a Task Force comprised of expert clinicians, trialists and regulators, summarises the current state of the art, and provides insight into the opportunities and challenges for identifying and assessing the efficacy and safety of new treatments for this challenging condition.

State of the art and research perspectives in clinical trial design and new therapies for pulmonary arterial hypertensionhttp://ow.ly/VHQ030mfRxc

Clinical and Echocardiographic Predictors of Outcomes in Patients With Pulmonary Hypertension

In pulmonary hypertension (PH), measurement of various echocardiographic parameters that assess right heart function is recommended by current clinical guidelines. Limited data exists on the combined value of clinical and echocardiographic parameters in precapillary PH in the modern era of therapy. We examined the association of clinical and echocardiographic parameters with surrogate outcomes (6-minute walk distance) and hard outcomes (hospitalization or death) in patients with precapillary PH. A cohort of patients with an established diagnosis of precapillary PH who underwent transthoracic echocardiography at the Duke Echo Lab were prospectively enrolled from 2010 to 2014. Univariable and multivariable models were constructed to examine the relation of clinical and echocardiographic parameters with surrogate and hard outcomes. Of the 98 patients with analyzable echocardiograms with good image quality, 85 were woman, mean age was 59.4 years, and 47% had ≥World Health Organization functional class III symptoms. The mean 6-minute walk distance was 354(±132) m, and 83% were on pulmonary arterial hypertension medications. At 24 months, the cumulative incidence rate for hospitalization or death was 47%. In univariable analyses, the REVEAL (Registry to Evaluate Early and Long-term PAH Disease Management) risk score (HR 1.72 per 1 SD (2.81) increment, 95% CI 1.34, 2.22; p=<0.001), RV global longitudinal strain (RVGLS) (HR 1.54 per 1 SD (5.31) worsening, 95% CI , 2.12; p=0.008) and log-2 NT proBNP (HR 1.43 per 1-fold increase, 95% CI 1.25, 1.63; p=<0.001) were significantly associated with hospitalization or death.

Self-reported functional status predicts post-operative outcomes in non-cardiac surgery patients with pulmonary hypertension

Background

Pulmonary hypertension (PHTN) is associated with increased post-procedure morbidity and mortality. Pre-procedure echocardiography (ECHO) is a widely used tool for evaluation of these patients, but its accuracy in predicting post-procedure outcomes is unproven. Self-reported exercise tolerance has not been evaluated for operative risk stratification of PHTN patients.

Objective

We analyzed whether self-reported exercise tolerance predicts outcomes (hospital length-of-stay [LOS], mortality and morbidity) in PHTN patients (WHO Class I–V) undergoing anesthesia and surgery.

Methods and findings

We reviewed 550 non-cardiac, non-obstetric procedures performed on 370 PHTN patients at a single institution between 2007 and 2013. All patients had cardiac ECHO documented within 1 year prior to the procedure. Pre-procedure comorbidities and ECHO data were collected. Functional status (< or ≥ 4 metabolic equivalents of task [METs]) was assigned based on responses to standard patient interview questions during the pre-anesthesia clinic visit. Multiple logistic regression was used to develop a risk score model (Pulmonary Hypertension Outcome Risk Score; PHORS) and determine its value in predicting post-procedure outcomes. In an adjusted model, functional status <4 METs was independently associated with a LOS >7 days (p < .003), as were higher ASA class (p < .002), open surgical approach (p < .002), procedure duration > 2 hours (p < .001), and the absence of systemic hypertension (p = .012). PHORS Score ≥2 was associated with an increased 30-day major complication rate (28.7% vs. 19.2%; p < 0.001) and ICU admission rate (8.6% s 2.8%; p = .007), but no statistical difference in hospital readmissions rate (17.6% vs. 14.0%; p = .29), or mortality (3.5% vs. 1.4%; p = .75). Similar ECHO findings did not further improve outcome prediction.

Conclusions

Poor functional status is associated with severe PHTN and predicts increased LOS and post-procedure complications in patients with moderate to severe pulmonary hypertension with different etiologies. A risk assessment model predicts increased LOS with fair accuracy. A thorough evaluation of underlying etiologies of PHTN should be undertaken in every patient.

Right Ventricular Longitudinal Strain Reproducibility Using Vendor-Dependent and Vendor-Independent Software

BACKGROUND

Right ventricular peak systolic longitudinal strain (RVLS) has emerged as an approach for quantifying right ventricular function in diseases such as pulmonary hypertension and congenital heart disease. A major limitation in applying RVLS is that strain imaging and analysis are proprietary, which may result in systematic differences from vendor to vendor. The goal of this study was to test the reproducibility of right ventricular strain analysis among selected vendor-specific software (VSS) and vendor-independent software (VIS) on images obtained from different ultrasound scanners, as would be common in clinical practice or in a multicenter clinical trial.

METHODS

In this prospective, single-center study, 35 patients (5 healthy subjects and 30 with pulmonary hypertension) each underwent two echocardiographic scans, one using GE (Vivid E9) and the other using Philips (iE33) ultrasound systems. Images were analyzed using both VSS and VIS (TomTec) software for determination of RVLS. A repeated-measures analysis of variance was used to assess for any systematic differences among methods, as well as effects of scanner and software and a possible interaction between scanner and software for each strain measurement.

RESULTS

Differences for global strains were not statistically significant among VSS packages (P ≥ .05), but some differences were noted between VSS and VIS. Wide variability between regional peak strain measurements was noted, but no systematic differences were found.

CONCLUSIONS

Global RVLS values between VSS systems are not significantly different but may differ slightly from VIS. When comparing regional strain between VSS and VIS analyses, there is widespread variability without clear systematic differences.

REVEAL risk score in patients with chronic thromboembolic pulmonary hypertension receiving riociguat

BACKGROUND

The REVEAL risk score (RRS) was developed to predict survival in patients with pulmonary arterial hypertension (PAH), based on multiple patient characteristics. Herein we calculated RRS for patients in the randomized CHEST-1 study and open-label CHEST-2 extension study of riociguat in inoperable or persistent/recurrent chronic thromboembolic pulmonary hypertension (CTEPH). We investigated the effect of riociguat vs placebo on RRS in the CHEST-1 study, and the relationship between RRS and long-term outcomes in the CHEST-2 study.

METHODS

RRS was calculated post hoc for baseline and Week 16 of CHEST-1 and Week 12 of CHEST-2, based on 9 evaluable elements. Patients were grouped into risk strata by RRS. Relationships between RRS and both survival and clinical worsening-free survival were examined by Kaplan-Meier and Cox proportional hazards analyses.

RESULTS

Overall, 237 patients completed CHEST-1 and entered CHEST-2. In CHEST-1, riociguat significantly improved RRS (p < 0.0001) and risk stratum (p < 0.001) vs placebo from baseline to Week 16. RRS at baseline, and at Week 16, and change in RRS during CHEST-1 were significantly associated with survival (hazard ratios for a 1-point reduction in RRS: 0.702, 0.692, and 0.682, respectively) and clinical worsening-free survival (hazard ratios: 0.697, 0.719, and 0.754, respectively) over 2 years in CHEST-2.

CONCLUSIONS

Riociguat improved RRS in patients with inoperable and persistent/recurrent CTEPH. RRS at baseline and Week 16, and change in RRS from baseline, predicted survival and clinical worsening-free survival. This analysis of RRS in patients with inoperable or persistent/recurrent CTEPH suggests utility for the RRS in indications beyond PAH.

Anxiety, Depression, and Health-Related QOL in Patients Diagnosed with PAH or CTEPH

BACKGROUND

Pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH) are life-threatening diseases with a high burden of symptoms. Although depression, anxiety, and reduced health related quality of life (HRQOL) have also been reported, a comparative analysis which explores these traits and their underlying factors was lacking.

METHODS

A retrospective analysis of depression, anxiety, and health related QOL was conducted using a Hospital anxiety and depression scale (HADS) as well as the SF-36 HRQOL questionnaire. Results from these tools were compared with haemodynamic and functional parameters in 70 PAH and 23 CTEPH outpatients from a German tertiary care center specializing in pulmonary hypertension.

RESULTS

Although HRQOL was reduced in both cohorts of patients, individuals diagnosed with CTEPH scored lower in nearly all SF-36 parameters. Significance was noted in both "mental health" (p = 0.01) and "mental component summary score" (MCS) (p = 0.02). Depression was also more frequent in patients with CTEPH (56%) than in patients with PAH (30%), (p = 0.03). Overall, depression and anxiety correlated with most SF-36 scales in both PAH and CTEPH. In CTEPH, depression also correlated with the Borg Dyspnea Scale (r = 0.44, p = 0.01). These patients also had significantly lower pCO₂ levels than the PAH cohort reflecting more severe ventilation/perfusion mismatch. All other haemodynamic and functional parameters did not differ across the groups.

CONCLUSION

While both cohorts of patients suffer from a reduced HRQOL as well as depression and anxiety, decreases in mental health parameters are more pronounced in the CTEPH cohort. This suggests a strong effort to improve early detection, especially in dyspneic patients with classical risk factors for CTEPH and PAH and argues for mental illness interventions alongside routine clinical care provided to patients diagnosed with PAH or CTEPH.

Targeted drugs for pulmonary arterial hypertension: a network meta-analysis of 32 randomized clinical trials

BACKGROUND

Pulmonary arterial hypertension (PAH) is a devastating disease and ultimately leads to right heart failure and premature death. A total of four classical targeted drugs, prostanoids, endothelin receptor antagonists (ERAs), phosphodiesterase 5 inhibitors (PDE-5Is), and soluble guanylate cyclase stimulator (sGCS), have been proved to improve exercise capacity and hemodynamics compared to placebo; however, direct head-to-head comparisons of these drugs are lacking. This network meta-analysis was conducted to comprehensively compare the efficacy of these targeted drugs for PAH.

METHODS

Medline, the Cochrane Library, and other Internet sources were searched for randomized clinical trials exploring the efficacy of targeted drugs for patients with PAH. The primary effective end point of this network meta-analysis was a 6-minute walk distance (6MWD).

RESULTS

Thirty-two eligible trials including 6,758 patients were identified. There was a statistically significant improvement in 6MWD, mean pulmonary arterial pressure, pulmonary vascular resistance, and clinical worsening events associated with each of the four targeted drugs compared with placebo. Combination therapy improved 6MWD by 20.94 m (95% confidence interval [CI]: 6.94, 34.94; P=0.003) vs prostanoids, and 16.94 m (95% CI: 4.41, 29.47; P=0.008) vs ERAs. PDE-5Is improved 6MWD by 17.28 m (95% CI: 1.91, 32.65; P=0.028) vs prostanoids, with a similar result with combination therapy. In addition, combination therapy reduced mean pulmonary artery pressure by 3.97 mmHg (95% CI: -6.06, -1.88; P<0.001) vs prostanoids, 8.24 mmHg (95% CI: -10.71, -5.76; P<0.001) vs ERAs, 3.38 mmHg (95% CI: -6.30, -0.47; P=0.023) vs PDE-5Is, and 3.94 mmHg (95% CI: -6.99, -0.88; P=0.012) vs sGCS. There were no significant differences in all-cause mortality and severe adverse events between prostanoids, ERAs, PDE-5Is, sGCS, combination therapy, and placebo.

CONCLUSION

All targeted drugs for PAH are associated with improved clinical outcomes, especially combination therapy. However, all these drugs seem to show less favorable effects on survival in the short-term follow-up, suggesting further clinical trials are required.