Pulmonary Arterial Hypertension (PAH) (WHO Group 1 PH)

The goal of this clinical study is to investigate whether the additional intake of sildenafil 20mg on top of standard medical treatment results in a benefit on maximum exercise workload (Wmax) in patients with pulmonary arterial hypertension (PAH).

Pulmonary hypertension (PH) is an uncommon condition and can often be difficult to diagnose. It means elevated blood pressure in the lungs which can rapidly lead to failure of the right side of the heart and is ultimately fatal. Diagnosing PH currently involves a number of scans, breathing tests and often an invasive test called right heart catheterisation \[RHC\] (which involves inserting a tube into a large vein to measure the lung blood pressure from the). The investigators propose using a scan of the nailbeds called "Nailfold (Video) Capillaroscopy" to see whether this measurements correspond to the pressures that the investigators measure at the time of RHC and whether these measures change with treatment for PH. The investigators wish to answer the hypotheses that: 1. The measurements of the nailbed blood vessels are correlated with the invasive right heart catheter values across all groups of PH 2. The abnormalities seen in systemic sclerosis are reversible with treatment with pulmonary vasodilator drugs 3. This change will be significantly more than any change seen in other types of pulmonary hypertension with these drugs 4. Changes in the nailbed blood vessels with treatment will reflect changes in the usual parameters used to measure treatment response in PH: The scan uses a camera microscope connected to a laptop, does not involve radiation and can be completed within 30 minutes. The results are sent to the University of Manchester where they are analysed by computer software. If patients are found to have pulmonary hypertension and are started on medication (pulmonary vasodilators) to open up the blood vessels of the lungs, the investigators will then repeat the scan at this point. The investigators will compare the results between different forms of PH before and after treatment.

Pulmonary arterial hypertension (PAH) is a rare, progressive, and potentially life-threatening disease characterized by pulmonary vascular remodeling, increased pulmonary vascular resistance, and right ventricular dysfunction. The endothelin pathway plays a central role in its pathophysiology and is targeted by endothelin receptor antagonists (ERAs), including ambrisentan and bosentan. Ambrisentan is a selective ETA receptor antagonist, whereas bosentan blocks both ETA and ETB receptors. Although transitions between ERAs occur in clinical practice, evidence regarding the clinical impact of switching from ambrisentan to bosentan remains limited. ACTION is a retrospective, observational, single-center cohort study evaluating adult patients with pulmonary arterial hypertension (World Health Organization Group 1) and/or chronic thromboembolic pulmonary hypertension (World Health Organization Group 4) confirmed by right heart catheterization. Patients who switched from ambrisentan to bosentan because of a national ambrisentan shortage will be compared with clinically similar patients who remained on ambrisentan. Clinical, functional, and laboratory data recorded at baseline and at 3 to 6 months of follow-up will be assessed. The primary outcome is the proportion of patients with worsening risk stratification after switching from ambrisentan to bosentan compared with patients who continued ambrisentan. Risk will be evaluated using the COMPERA 2.0 and REVEAL Lite 2 assessment tools. Secondary outcomes include changes in World Health Organization/New York Heart Association functional class, 6-minute walk distance, BNP levels, individual risk-assessment components, hepatic enzymes, hemoglobin levels, and clinically relevant events such as hospitalization, emergency department visits, initiation of supplemental oxygen, and right heart failure decompensation.

This study evaluates the effects of VI-0106 (an extended-release formulation of tacrolimus) in participants with pulmonary arterial hypertension (PAH) who continue to have functional limitations despite being on optimized background PAH therapy. Participants will be randomly assigned with equal chance to receive either VI-0106 or placebo in a double-blind fashion to assess whether VI-0106 improves outcomes in this population.

This methodological study aims to develop and validate a questionnaire named for the Assessment of Patient Knowledge in Pulmonary Arterial Hypertension. The study will be conducted in four phases: (1) questionnaire development based on guidelines and literature; (2) content validation by expert judges; (3) semantic validation with patients; and (4) psychometric testing in a sample of up to 200 patients with confirmed pulmonary arterial hypertension (PAH). In addition to validation, the study will collect clinical and functional data from medical records, including risk stratification using the COMPERA 2.0 method The final instrument is expected to support patient education strategies and contribute to improved clinical management of PAH.

The goal of this observational study is to learn more about how genes impact the risk of pulmonary hypertension. Anyone 18 or older living in the US is eligible, and a diagnosis of PH is NOT required. Study participation is online, and it takes about 20 minutes to complete health surveys and request a saliva collection kit sent through US mail. In return, study participants may opt to receive information about their genetic ancestry at no cost.

Understanding Delays in the Diagnosis of Pulmonary Arterial Hypertension and Rare Diseases in Brazil: A Multicenter Observational Study \--- Pulmonary arterial hypertension (PAH) is a rare, progressive, and life-threatening disease that affects the arteries of the lungs and the right side of the heart. Early diagnosis is essential to initiate appropriate treatment and improve patient outcomes. However, worldwide studies show that there is often a significant delay between the onset of symptoms and the final diagnosis. This delay may lead to disease progression and worse survival. This multicenter observational study aims to understand the time from the first symptoms to the diagnosis of PAH and other rare diseases across several Brazilian reference centers. By analyzing medical records and patient journeys, the investigators intends to identify factors contributing to delayed diagnosis and potential opportunities for earlier detection. The study includes adult patients diagnosed with PAH or other selected rare diseases within the last five years. The investigators will analyze time to diagnosis, number and type of physicians consulted, tests performed, and possible misdiagnoses. Our goal is to support the development of strategies that reduce diagnostic delay and improve access to specialized care for people living with rare diseases. This study does not involve any intervention and poses no additional risk to participants, as it is based solely on retrospective data from medical records.

Pulmonary arterial hypertension (PAH) is a progressive condition with high morbidity, frequent hospitalizations, and risk of right heart failure. Despite advances in treatment, poor adherence remains a major challenge. This randomized controlled study assesses whether remote monitoring can improve treatment adherence, clinical outcomes, and side effect management in PAH patients on oral therapy.