Selexipag in the management of pulmonary arterial hypertension: an update

Selexipag is a compound that was designed to overcome the issues associated with oral administration of prostanoid compounds, beraprost and treprostinil in the treatment of pulmonary hypertension (PAH). As a selective IP agonist, it was designed to avoid the off-target prostanoid effects especially in the gastrointestinal system. To place this compound in context, this paper briefly reviews the efficacy, tolerability, and safety of subcutaneous, inhaled, and oral prostanoid preparations and comparesthemto selexipag. Selexipag is the first agent targeting a prostanoid receptor where a reduction in the primary efficacy morbidity/mortality composite end-point has been demonstrated. While safety outcomes favor selexipag over placebo, tolerability issues remain. Efficacy in terms of improvement in effort tolerance, hemodynamic and mortality benefit is less than seen with IV therapy. This is the first prostanoid demonstrated in a clinical trial to have added benefit in those on background double combination therapy and the first non IV prostanoid to demonstrate outcome benefit in the connective tissue disease (CTD) population in a randomized controlled trial

Major lung complications of systemic sclerosis (vol 14, pg 511, 2018)

Systemic sclerosis (SSc) is associated with high mortality owing to internal organ complications and lung disease is the leading cause of SSc-associated death. The most notable lung complications in SSc are fibrosis and pulmonary arterial hypertension (PAH). A major challenge for the management of lung disease in SSc is detecting those patients with severe pathology and those patients that are likely to benefit from available treatments. In the past few, strategies for managing lung fibrosis and pulmonary hypertension, including PAH, have greatly progressed. For lung fibrosis, the tools to assess risk of progression and severity of the disease have been refined. Clinical trial results support the use of immunosuppression, including high intensity regimens with autologous stem cell transplantation. New trials are underway to test other potential therapies including treatments that are approved for use in idiopathic lung fibrosis. For PAH, identifying individuals at high risk of disease development is critical. In addition, individuals who have borderline elevation of pulmonary arterial pressure need to be appropriately managed and followed up. Many approved drugs targeting PAH are now available and results from large-scale clinical trials provide robust evidence that various treatments for SSc-associated PAH are associated with good long-term outcomes

Aggressive combination therapy for treatment of systemic sclerosis-associated pulmonary hypertension

Pulmonary arterial hypertension is an important complication of systemic sclerosis with high mortality but should be regarded as a treatable manifestation of the disease. Management draws on experience from other forms of pulmonary arterial hypertension and benefits from an increasing number of licenced therapies. Outcome is variable but recent clinical trials suggest that combination therapies used early in the disease may be associated with better outcomes. This is important because previous clinical trials using short-term gain in exercise capacity did not show significant benefit compared to that observed for idiopathic or heritable forms of pulmonary arterial hypertension. Thus, it is important to identify cases as early as possible and to manage cases that are in a high-risk group using early combination therapy. This review summarises the most recent analyses of clinical trial data, with a focus on those patients with SSc-associated pulmonary arterial hypertension and provides the evidence base that supports current treatment recommendations for aggressive pulmonary arterial hypertension occurring in systemic sclerosis, including the early use of combination pulmonary arterial hypertension–specific drugs in appropriate cases

Accuracy and Test-Retest Reproducibility of Two-Dimensional Knowledge-Based Volumetric Reconstruction of the Right Ventricle in Pulmonary Hypertension

Right heart function is the key determinant of symptoms and prognosis in pulmonary hypertension (PH), but the right ventricle has a complex geometry that is challenging to quantify by two-dimensional (2D) echocardiography. A novel 2D echocardiographic technique for right ventricular (RV) quantitation involves knowledge-based reconstruction (KBR), a hybrid of 2D echocardiography-acquired coordinates localized in three-dimensional space and connected by reference to a disease-specific RV shape library. The aim of this study was to determine the accuracy of 2D KBR against cardiac magnetic resonance imaging in PH and the test-retest reproducibility of both conventional 2D echocardiographic RV fractional area change (FAC) and 2D KBR

Reduced exercise capacity in patients with systemic sclerosis is associated with lower peak tissue oxygen extraction: a cardiovascular magnetic resonance-augmented cardiopulmonary exercise study

Background: Exercise intolerance in systemic sclerosis (SSc) is typically attributed to cardiopulmonary limitations. However, problems with skeletal muscle oxygen extraction have not been fully investigated. This study used cardiovascular magnetic resonance (CMR)-augmented cardiopulmonary exercise testing (CMR-CPET) to simultaneously measure oxygen consumption and cardiac output. This allowed calculation of arteriovenous oxygen content gradient, a recognized marker of oxygen extraction. We performed CMR-CPET in 4 groups: systemic sclerosis (SSc); systemic sclerosis-associated pulmonary arterial hypertension (SSc-PAH); non-connective tissue disease pulmonary hypertension (NC-PAH); and healthy controls. Methods: We performed CMR-CPET in 60 subjects (15 in each group) using a supine ergometer following a ramped exercise protocol until exhaustion. Values for oxygen consumption, cardiac output and oxygen content gradient, as well as ventricular volumes, were obtained at rest and peak-exercise for all subjects. In addition, T1 and T2 maps were acquired at rest, and the most recent clinical measures (hemoglobin, lung function, 6-min walk, cardiac and catheterization) were collected. Results: All patient groups had reduced peak oxygen consumption compared to healthy controls (p<0.022). The SSc and SSc-PAH groups had reduced peak oxygen content gradient compared to healthy controls (p<0.03). Conversely, the SSc-PAH and NC-PH patients had reduced peak cardiac output compared to healthy controls and SSc patients (p<0.006). Higher hemoglobin was associated with higher peak oxygen content gradient (p=0.025) and higher myocardial T1 was associated with lower peak stroke volume (p=0.011). Conclusions: Reduced peak oxygen consumption in SSc patients is predominantly driven by reduced oxygen content gradient and in SSc-PAH patients this was amplifed by reduced peak cardiac output

Riociguat for the treatment of pulmonary arterial hypertension associated with connective tissue disease: results from PATENT-1 and PATENT-2

BACKGROUND: The 12-week, phase III Pulmonary Arterial hyperTENsion sGC-stimulator Trial (PATENT)-1 study investigated riociguat in patients with pulmonary arterial hypertension (PAH). Here, we present a prospectively planned analysis of the safety and efficacy of riociguat in the subgroup of patients with PAH associated with connective tissue disease (PAH-CTD). METHODS: Patients with PAH-CTD were further classified post hoc as having PAH associated with systemic sclerosis or PAH-other defined CTD. In PATENT-1, patients received riociguat (maximum 2.5 or 1.5 mg three times daily) or placebo. Efficacy endpoints included change from baseline in 6-minute walking distance (6MWD; primary endpoint), haemodynamics and WHO functional class (WHO FC). In the long-term extension PATENT-2, patients received riociguat (maximum 2.5 mg three times daily); the primary endpoint was safety and tolerability. RESULTS: In patients with PAH-CTD, riociguat increased mean 6MWD, WHO FC, pulmonary vascular resistance and cardiac index. Improvements in 6MWD and WHO FC persisted at 2 years. Two-year survival of patients with PAH-CTD was the same as for idiopathic PAH (93%). Riociguat had a similar safety profile in patients with PAH-CTD to that of the overall population. CONCLUSIONS: Riociguat was well tolerated and associated with positive trends in 6MWD and other endpoints that were sustained at 2 years in patients with PAH-CTD. TRIAL REGISTRATION NUMBERS: PATENT-1 (NCT00810693), PATENT-2 (NCT00863681)

Cardiovascular magnetic resonance-guided right heart catheterization in a conventional CMR environment - predictors of procedure success and duration in pulmonary artery hypertension

Background Cardiovascular magnetic resonance imaging (CMR) is valuable for the investigation and management of pulmonary artery hypertension (PAH), but the direct measurement of pulmonary hemodynamics by right heart catheterization is still necessary. CMR-guided right heart catheterization (CMR-RHC) combines the benefits of CMR and invasive cardiac catheterization, but its feasibility in patients with acquired PAH has not been established. The aims of this study are to: (1) demonstrate the feasibility of CMR-RHC in patients being assessed for PAH in a conventional diagnostic CMR scanner room; (2) determine the predictors of (i) procedure duration, and (ii) procedural failure or technical difficulty as determined by the adjunctive need for a guidewire. Methods Fifty patients investigated for suspected or known PH underwent CMR-RHC. Durations of separate procedural components were recorded, including time taken to pass the catheter from the femoral vein to a stable wedge position (procedure time) and total time the patient spent in the CMR department (department time). Associations between procedural failure/guidewire usage and hemodynamic/CMR measures were assessed using logistic regression. Relationships between procedure times and hemodynamic/CMR measures were evaluated using Spearman’s correlation coefficient. Results A full CMR-RHC study was successfully completed in 47 (94%) patients. CMR-conditional guidewires were used in 6 (12%) patients. Metrics associated with guidewire use/procedural failure were higher mean pulmonary artery (PA) pressures (mPAP: OR = 1.125, p = 0.018), right heart dilatation (right ventricular (RV) end-systolic volume (RVESV): OR = 1.028, p = 0.018), RV hypertrophy (OR = 1.050, p = 0.0067) and RV ejection fraction (EF) (OR = 0.914, p = 0.014). Median catheter and department times were 3.6 (2.0–7.7) minutes and 60.0 (54.0–68.5) minutes, respectively. All procedure times became significantly shorter with increasing procedural experience (p < 0.05). Catheterization time was also associated with PH severity (RV systolic pressure: rho = 0.46, p = 0.0013) and increasing RV end-systolic volume (RVESV: rho = 0.41, p = 0.0043), hypertrophy (rho = 0.43, p = 0.0025) and dysfunction (RVEF: rho = − 0.32, p = 0.031). Conclusions This study demonstrates that CMR-RHC using standard technology can be incorporated into routine clinical practice for the investigation of PAH. Procedural failure was rare but more likely in patients with severe PAH. Procedure time is clinically acceptable and increases with worsening PAH severity

Two-dimensional knowledge-based volumetric reconstruction of the right ventricle documents short-term improvement in pulmonary hypertension

BACKGROUND: Data are scarce about short-term right ventricular changes in pulmonary hypertension. Two-dimensional knowledge-based reconstruction of the right ventricle with 2D echocardiography (2DKBR) has been shown to be a valid alternative to Cardiac MRI. PATIENTS AND METHODS: In this longitudinal study 25 pulmonary hypertension patients underwent 2DKBR of the right ventricle, assessment of NT-proBNP levels and functional class at baseline and after a mean follow-up of 6.1 months. Patients were followed up clinically for a further mean of 8.2 months. The majority of patients had connective tissue disease (CTD) associated pulmonary arterial hypertension (n=15) or chronic thromboembolic pulmonary hypertension (CTEPH; n=6). A total of 15 patients underwent an intervention, either new targeted therapy, escalation of targeted therapy or pulmonary endarterectomy. A total of 10 clinically stable patients were routinely followed up without any change in therapy. RESULTS: There were significant improvements in the right ventricular end-diastolic volume index (111±29 mL/m² vs 100±36 mL/m²; P=.038), end-systolic volume index (72±23 mL/m² vs 61±25 mL/m²; P=.001), and ejection fraction (35±10% vs 40±9%; P=.030). Changes in NT-proBNP levels correlated strongest with changes in end-systolic volume index (r=-.77; P=<.0001). Four patients experienced clinical worsening during extended follow-up, dilatation of the right ventricle was associated with clinical worsening. CONCLUSION: In a CTD and CTEPH dominated patient population significant reverse remodeling and improvement of ejection fraction occurred despite a short follow-up and was paralleled by significant changes in NT-proBNP levels. Further right ventricular dilatation was associated with worse clinical outcome. 2DKBR is a feasible substitute for Cardiac MRI to follow-up right ventricular indices in pulmonary hypertension

Accuracy and reproducibility of right ventricular quantification in patients with pressure and volume overload using single-beat three-dimensional echocardiography.

The right ventricle is a complex structure that is challenging to quantify by two-dimensional (2D) echocardiography. Unlike disk summation three-dimensional (3D) echocardiography (3DE), single-beat 3DE can acquire large volumes at high volume rates in one cardiac cycle, avoiding stitching artifacts or long breath-holds. The aim of this study was to assess the accuracy and test-retest reproducibility of single-beat 3DE for quantifying right ventricular (RV) volumes in adult populations of acquired RV pressure or volume overload, namely, pulmonary hypertension (PH) and carcinoid heart disease, respectively. Three-dimensional and 2D echocardiographic indices were also compared for identifying RV dysfunction in PH