Updating clinical endpoint definitions

Assessment of right ventricular remodeling in chronic thromboembolic pulmonary hypertension by 2D-speckle tracking echocardiography: A comparison with cardiac magnetic resonance

Background

Right heart remodeling occurs in a substantial proportion of patients with chronic thromboembolic pulmonary hypertension (CTEPH) and significantly affects their prognosis. Two-dimensional speckle-tracking echocardiography (2D-STE) can be used to evaluate myocardial deformation under physiological and pathological conditions. This study aimed to assess the feasibility of 2D-STE for evaluating right ventricular (RV) remodeling in CTEPH patients.

Methods

This retrospective study included 21 CTEPH patients who underwent transthoracic echocardiography (TTE) and cardiac magnetic resonance (CMR). Data for the following parameters that can reflect RV function were collected: tricuspid annular plane systolic excursion (TAPSE), fractional area change (FAC), right ventricular index of myocardial performance (RIMP), peak systolic velocity of the tricuspid annulus (S'), and CMR-right ventricular ejection fraction (CMR-RVEF). The following strain parameters were calculated using post-processing software: STE-RV global longitudinal strain (STE-RVGLS), STE-RV free wall longitudinal strain (STE-RVFWLS), and CMR-RVGLS.

Results

As CMR-RVEF deteriorated, RV remodeling in CTEPH patients became more apparent and was mainly characterized by significant enlargement of the RV, weakening of myocardial deformation, and a decrease in RV contractility (RV area, STE-RVFWLS, STE-RVGLS: mild vs. severe and moderate vs. severe, p < 0.05; CMR-RVGLS: mild vs. severe, p < 0.05; TAPSE: moderate vs. severe, p < 0.05). Moreover, the Pearson correlation coefficient for correlation with CMR-derived RVEF was stronger for RVFWLS than for CMR-GLS (r-value: 0.70 vs. 0.68), and the strain values measured by 2D-STE showed a weak correlation with right heart catheterization data. Bland-Altman analysis showed good agreement between 2D-STE and CMR-feature tracking (FT) for RVGLS (bias = −0.96; 95% limit of agreement from −8.42 to 6.49).

Conclusions

For the measurement of RVGLS, 2D-STE is similarly feasible to CMR-FT and could sensitively identify right heart remodeling.

Pulmonary arterial hypertension associated with congenital heart disease: lessons learnt from the large Turkish Nationwide Registry (THALES)

Pulmonary hypertension is a group of diseases, including pulmonary arterial hypertension associated with congenital heart disease (APAH-CHD), characterized by progressive deterioration in pulmonary hemodynamics associated with substantial morbidity and mortality risk. THALES is a national multicenter, prospective observational registry, providing data on patients with APAH-CHD. The study comprised APAH-CHD patients (>3 months of age) with confirmed diagnosis of right heart catheterization or echocardiographic findings. Initial and follow-up data were collected via regular hospital visits. Descriptive statistics are used for definitive purposes. Overall, 1034 patients aged 3 months–79 years (median 11.2 [Q1–Q3: 2.2–24.3] years) with APAH-CHD were enrolled at 61 centers, 50.3% being retrospectively enrolled. Most had either Eisenmenger's syndrome (49.2%) or systemic-to-pulmonary shunts (42.7%). Patients were mostly in functional class I–II at the time of diagnosis (46.6%). Mean 6-min walk distance (6MWD) was 369 ± 120 m. Mean pulmonary arterial pressure was 54.7 ± 22.2 mmHg for the whole group, and was highest in patients with Eisenmenger's syndrome. Targeted therapies were noted in 398 (38.5%) patients (monotherapy in 80.4%). Follow-up data were available in 506 patients. Survival at 140 months was 79% and was associated with baseline 6MWD >440 m (p = 0.009), brain natriuretic peptide level < 300 ng/L (p < 0.001). Follow-up 6MWD >165 m (p < 0.0001), brain natriuretic peptide level <300 ng/L (p = 0.031), and targeted therapies (p = 0.004) were also predictive of survival. THALES is the largest registry dedicated to APAH-CHD to date and provides important contributions on demographics, clinical characteristics, and gaps in disease management.

Novel composite clinical endpoints and risk scores used in clinical trials in pulmonary arterial hypertension

This manuscript on endpoints incorporates the broad experience of members of Pulmonary Vascular Research Institute’s Innovative Drug Development Initiative as an open debate platform for academia, the pharmaceutical industry and regulatory experts surrounding the future design of clinical trials in pulmonary hypertension. It reviews our current understanding of endpoints used in phase 2 and 3 trials for pulmonary hypertension and discusses in detail the value of newer approaches. These include the roles of composite endpoints and how these can be developed and validated. The newer concept of risk analysis is also discussed, including how such risk scores might be utilised as endpoints in clinical trials.

Emerging role of cardiovascular magnetic resonance imaging in the management of pulmonary hypertension

Pulmonary hypertension (PH) is a clinical condition characterised by elevation of pulmonary arterial pressure (PAP) above normal range due to various aetiologies. While cardiac right-heart catheterisation (RHC) remains the gold standard and mandatory for establishing the diagnosis of PH, noninvasive imaging of the heart plays a central role in the diagnosis and management of all forms of PH. Although Doppler echocardiography (ECHO) can measure a range of haemodynamic and anatomical variables, it has limited utility for visualisation of the pulmonary artery and, oftentimes, the right ventricle. Cardiovascular magnetic resonance (CMR) provides comprehensive information about the anatomical and functional aspects of the pulmonary artery and right ventricle that are of prognostic significance for assessment of long-term outcomes in disease progression. CMR is suited for serial follow-up of patients with PH due to its noninvasive nature, high sensitivity to changes in anatomical and functional parameters, and high reproducibility. In recent years, there has been growing interest in the use of CMR derived parameters as surrogate endpoints for early-phase PH clinical trials. This review will discuss the role of CMR in the diagnosis and management of PH, including current applications and future developments, in comparison to other existing major imaging modalities.

Multi-Beat Right Ventricular-Arterial Coupling Predicts Clinical Worsening in Pulmonary Arterial Hypertension

Background Although right ventricular (RV) to pulmonary arterial (RV-PA) coupling is considered the gold standard in assessing RV dysfunction, its ability to predict clinically significant outcomes is poorly understood. We assessed the ability of RV-PA coupling, determined by the ratio of multi-beat (MB) end-systolic elastance (Ees) to effective arterial elastance (Ea), to predict clinical outcomes. Methods and Results Twenty-six subjects with pulmonary arterial hypertension (PAH) underwent same-day cardiac magnetic resonance imaging, right heart catheterization, and RV pressure-volume assessment with MB determination of Ees/Ea. RV ejection fraction (RVEF), stroke volume/end-systolic volume, and single beat-estimated Ees/Ea were also determined. Patients were treated with standard therapies and followed prospectively until they met criteria of clinical worsening (CW), as defined by ≥10% decline in 6-minute walk distance, worsening World Health Organization (WHO) functional class, PAH therapy escalation, RV failure hospitalization, or transplant/death. Subjects were 57±14 years, largely WHO class III (50%) at enrollment, with preserved average RV ejection fraction (RVEF) (47±11%). Mean follow-up was 3.2±1.3 years. Sixteen (62%) subjects met CW criteria. MB Ees/Ea was significantly lower in CW subjects (0.7±0.5 versus 1.3±0.8, P=0.02). The optimal MB Ees/Ea cut-point predictive of CW was 0.65, defined by ROC (AUC 0.78, P=0.01). MB Ees/Ea below this cut-point was significantly associated with time to CW (hazard ratio 5.1, P=0.001). MB Ees/Ea remained predictive of outcomes following multivariate adjustment for timing of PAH diagnosis and PAH diagnosis subtype. Conclusions RV-PA coupling as measured by MB Ees/Ea has prognostic significance in human PAH, even in a cohort with preserved RVEF.

Echocardiographic Assessment of Right Ventricular Function and Response to Therapy in Pulmonary Arterial Hypertension

Echocardiography is a key tool in the management of patients with pulmonary arterial hypertension (PAH), but many potential parameters could be used to assess response to therapy. In this retrospective study of 48 patients with severe PAH at baseline, we examined echocardiographic variables before and after initiation of PAH-specific therapy to evaluate which measures of right ventricular (RV) function best correlated with clinical response to therapy as assessed by 6-minute walk distance (6MWD) and 3-year all-cause mortality. Tricuspid annular plane systolic excursion (TAPSE), mid-RV and basal-RV diameters, RV systolic pressure, and RV global longitudinal strain were all found to significantly improve after initiation of a PAH therapy. Decreases in right atrial area (r = -0.50, p = 0.002) and mid-RV diameter (r = -0.36, p = 0.03) were most strongly correlated with improvement in 6MWD. Pretreatment values of RA area (hazard ratio [HR] per 1 SD: 2.72; 95% confidence interval [CI] 1.58, 4.69), mid-RV diameter (HR 2.03; 1.20, 3.45), basal-RV diameter (HR 2.27; 1.40, 3.70), and RV global longitudinal strain (HR 2.36; 1.22, 4.56) were all associated with mortality risk. 6MWD and TAPSE were the 2 variables for which pretreatment measures (6MWD - HR 0.35; 0.17, 0.72; TAPSE - HR 0.41; 0.21, 0.82) and change with treatment (6MWD - HR 0.26; 0.10, 0.64; TAPSE - HR 0.40; 0.21, 0.77) were both significantly associated with 3-year mortality. Change in RV systolic pressure with treatment was significantly associated with mortality (HR 2.55; 1.23, 5.28,) but pretreatment baseline had no association (HR 1.48; 0.72, 3.06). Although many echocardiographic parameters change with initiation of PAH treatment, the strong association of both baseline TAPSE and change in TAPSE with mortality supports the ongoing use of TAPSE as an important measure in the assessment of disease severity and treatment response in PAH.

Evaluation of Clinical Outcomes and Simultaneous Digital Tracking of Daily Physical Activity, Heart Rate, and Inhalation Behavior in Patients With Pulmonary Arterial Hypertension Treated With Inhaled Iloprost: Protocol for the Observational VENTASTEP Study

BACKGROUND

Pulmonary arterial hypertension (PAH)-a progressive, ultimately fatal disease-patients often experience dyspnea, which can limit their daily physical activities. Iloprost is an inhaled therapy for PAH that has shown efficacy in clinical trials. However, clinical trials in PAH have provided only limited data on daily physical activity. Digital monitoring of daily physical activity in PAH is therefore attracting growing interest. To fully understand a patient's response to treatment, monitoring of treatment adherence is also required. The Breelib nebulizer for administration of iloprost saves inhalation data, thus allowing digital monitoring of adherence.

OBJECTIVE

This study aims to perform parallel digital tracking of daily physical activity parameters, heart rate, and iloprost inhalation data in patients with PAH, before and after starting inhaled iloprost treatment. The primary objective is to investigate correlations between changes in digital measures of daily physical activity and traditional clinical measures. Secondary objectives are to assess iloprost inhalation behavior, the association between daily physical activity measures and time since last inhalation, changes in sleep quality and heart rate, the association of heart rate with daily physical activity measures and iloprost inhalation, and adverse events.

METHODS

VENTASTEP is a digital, prospective, observational, multicenter, single-arm cohort study of adults with PAH in Germany, starting inhaled iloprost treatment via the Breelib nebulizer, in addition to existing PAH therapy. The study comprises a baseline period without iloprost treatment (≤2 weeks) and an observation period with iloprost treatment (3 months±2 weeks). The Apple Watch Series 2 and iPhone 6s are used with a dedicated study app to continuously measure digital daily physical activity parameters and heart rate during the baseline and observation periods; the watch is also used with a 6-min walk distance (6MWD) app to measure digital 6MWD at baseline and the end-of-observation visit. Inhalation frequency, completeness, and duration are monitored digitally via the nebulizer and the BreeConnect app. Sleep quality is assessed using the Pittsburgh Sleep Quality Index at baseline and the end-of-observation visit. Changes in traditional outcome measures (6MWD, Borg dyspnea scale, EuroQol 5-dimensions questionnaire, functional class, and brain natriuretic peptide [BNP] or N-terminal proBNP) between baseline and the end-of-observation visit will be correlated with changes in digital daily physical activity parameters and digital 6MWD as the primary analysis.

RESULTS

The first participant was enrolled in February 2018 (estimated study completion by July 2019; planned sample size: 80 patients).

CONCLUSIONS

The VENTASTEP study will inform future research on the utility of digital parameters as outcome assessment tools for disease monitoring in PAH. The study will also provide insight into clinical outcomes, daily physical activity, and quality of life in patients adding inhaled iloprost, to existing PAH therapy.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03293407; https://clinicaltrials.gov/ct2/show/NCT03293407 (Archived by WebCite at http://www.webcitation.org/6ywPGcn4I).

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/12144.

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.

Pulmonary Hypertension and Indicators of Right Ventricular Function

Pulmonary hypertension (PH) is a rare disease, whose underlying mechanisms are not fully understood. It is characterized by pulmonary arterial vasoconstriction and vessels wall thickening, mainly intimal and medial layers. Several molecular pathways have been studied, but their respective roles remain unknown. Cardiac repercussions of PH are hypertrophy, dilation, and progressive right ventricular dysfunction. Multiple echocardiographic parameters are being used, in order to assess anatomy and cardiac function, but there are no guidelines edited about their usefulness. Thus, it is now recommended to associate the best-known parameters, such as atrial and ventricular diameters or tricuspid annular plane systolic excursion. Cardiac catheterization remains necessary to establish the diagnosis of PH and to assess pulmonary hemodynamic state. Concerning energetic metabolism, free fatty acids, normally used to provide energy for myocardial contraction, are replaced by glucose uptake. These abnormalities are illustrated by increased (18)F-fluorodeoxyglucose ((18)F-FDG) uptake on positron emission tomography/computed tomography, which seems to be correlated with echocardiographic and hemodynamic parameters.

Clinical pharmacokinetics and pharmacodynamics of the endothelin receptor antagonist macitentan

Pulmonary arterial hypertension (PAH) is a progressive disease of the lung vascular system, which leads to right-sided heart failure and ultimately death if untreated. Treatments to regulate the pulmonary vascular pressure target the prostacyclin, nitric oxide, and endothelin (ET) pathways. Macitentan, an oral, once-daily, dual ET_A and ET_B receptor antagonist with high affinity and sustained receptor binding is the first ET receptor antagonist to show significant reduction of the risk of morbidity and mortality in PAH patients in a large-scale phase III study with a long-term outcome. Here we present a review of the available clinical pharmacokinetic, pharmacodynamic, pharmacokinetic/pharmacodynamic relationship, and drug–drug interaction data of macitentan in healthy subjects, patients with PAH, and in special populations.

Dual phosphodiesterase type 5 inhibitor therapy for refractory pulmonary arterial hypertension: a pilot study

BACKGROUND

Recent vasodilating drugs have improved prognosis of Pulmonary arterial hypertension (PAH). Some reports describe the merits of combination therapies for PAH, and this study evaluated the efficacy and safety of phosphodiesterase type 5 inhibitors (PDE5i) combination therapy, using sildenafil and tadalafil, for multi-drug-resistant PAH.

METHODS

We retrospectively analyzed 7 consecutive refractory patients with PAH administered either sildenafil 60 mg or tadalafil 40 mg as well as both ERA and prostanoid as combination therapies. All were started on the dual PDE5i (sildenafil and tadalafil at maximum dose).

RESULTS

Treatment was generally well tolerated without severe adverse events. On completion of the study, the seven patients received right heart catheterization and the 6-minute walk test (6WMT) 9.6 ± 1.4 months after initiation of the dual PDE5i therapy, showing significant improvements in hemodynamic parameters and exercise tolerance. Mean pulmonary arterial pressure and pulmonary vascular resistance decreased from 47.9 ± 9.7 to 41.7 ± 9.2 mmHg (P = 0.004) and 9.3 ± 2.7 to 6.7 ± 2.9 mmHg (P = 0.018), respectively. Cardiac index and 6MWT also increased from 2.8 ± 0.9 to 3.1 ± 0.8 L/min/m(2) (P = 0.026) and 353 ± 60 to 382 ± 62 m (P = 0.014), respectively.

CONCLUSION

The findings support dual PDE5i therapy as a new treatment option for refractory PAH.

An update on medical therapy for pulmonary arterial hypertension

Over the past 20 years, great progress has been made in the treatment of pulmonary arterial hypertension (PAH). Available therapies target one of three principal pathways: the endothelin (ET), nitric oxide (NO) or the prostacyclin (PGI2) pathway. Evidence shows that current drugs, used either as monotherapy or in different combinations, can improve exercise capacity, clinical symptoms, hemodynamics and even survival in PAH. Unfortunately, the disease remains incurable and the prognosis of the disease is still poor. However, existing and novel potent antiproliferative therapies are being explored, and new agents targeting different and/or additional pathways are likely to become available to clinicians in the near future. Promising candidates include tyrosine kinase antagonists (e.g. imatinib); soluble guanylate cyclase stimulators (riociguat); an oral analog of prostacyclin (selexipag); and a tissue targeting endothelin receptor antagonist (macitentan). Phase II or III trials have either been completed or are underway to evaluate the safety and efficacy of these various therapies.

Interdisciplinary networks for the treatment of childhood pulmonary vascular disease: what pulmonary hypertension doctors can learn from pediatric oncologists

The pathobiology of pulmonary arterial hypertension (PAH) is complex and multifactorial. None of the current therapies has been shown to be universally effective or able to reverse advanced pulmonary vascular disease, characterized by plexiform vascular lesions, or to prevent right ventricular failure in advanced PAH. It is thus unlikely that only one factor, pathway, or gene mutation will explain all forms and cases. Pediatric oncologists recognized a need for intensified, collaborative research within their field more than 40 years ago and implemented major clinical and translational networks worldwide to achieve evidence-based "tailored therapies." The similarities in the pathobiology (e.g., increased proliferation and resistance to apoptosis in vascular cells and perivascular inflammation) and the uncertainties in the proper treatment of both cancer and pulmonary hypertension (PH) have led to the idea of building interdisciplinary networks among PH centers to achieve rapid translation of basic research findings, optimal diagnostic algorithms, and significant, sustained treatment results. Such networks leading to patient registries, clinical trials, drug development, and innovative, effective therapies are urgently needed for the care of children with PH. This article reviews the current status, limitations, and recent developments in the field of pediatric PH. It is suggested that the oncologists' exemplary networks, concepts, and results in the treatment of acute lymphoblastic leukemia are applicable to future networks and innovative therapies for pediatric pulmonary hypertensive vascular disease and right ventricular dysfunction.

An exploratory panel of biomarkers for risk prediction in pulmonary hypertension: emerging role of CT-proET-1

BACKGROUND

Pulmonary arterial hypertension (PAH) is a rare, deadly condition. Although risk stratification is extremely important for assessment of prognosis and to guide therapy, there is lack of evidence concerning the role of novel biomarkers. In a pivotal study, we sought to comparatively investigate the predictive power of several new biomarkers in PAH.

METHODS

Patients with prevalent PAH were enrolled in the study protocol, which included clinical, functional and echocardiographic assessment. Blood samples were collected at baseline for determination of NT-proBNP, CT-proET-1, MR-proANP, MR-proADM, copeptin and troponin I. Patients were clinically followed-up up to 12 months for first occurrence of hospital admission due to PAH-related clinical worsening, heart/lung transplantation or all-cause mortality.

RESULTS

Among the 28 included patients the pre-specified end-point occurred in 8 (29% event rate). There were higher baseline levels of CT-proET-1, copeptin, MR-proANP, NT-proBNP and troponin I in patients who reached the composite end-point. They also had larger right atria. In multivariate Cox regression, CT-proET-1 was the only biomarker associated with increased hazard of reaching the primary composite end-point (hazard ratio per tertile increase = 10.1; 95% CI 2.0 to 50.6).

CONCLUSIONS

CT-proET-1 provided prognostic information independent of other biomarkers. Importantly, we have provided the first evidence that CT-proET-1 may be superior to commonly used biomarkers.