Acute Effects of Benzbromaron on the Pulmonary Circulation

Study Overview
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Brief Summary
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Actual studies suggest that a calcium activated chlorid channel (TMEM16A) may play a relevant role in the pathogenesis of pulmonary arterial hypertension (PAH). The inhibition of this channel led to pulmonary vasorelaxation in preclinical studies. Benzbromarone is a well known inhibitor of the TMEM16A channel and is used in patients with gout. In this pilot study the investigators plan to investigate if Benzbromarone has an acute effect on the pulmonary arteries in humans. This will be investigated within the frame of a right heart catheterization performed in patients with known PAH due to clinical reasons. The investigators hypothesize that the application of Benzbromarone leads to pulmonary vasodilation, which can be recognized by the decrease in pulmonary vascular resistance. In addition, the change in pulmonary and systemic arterial pressure, pulmonary arterial wedge pressure, heart rate and arterial oxygen saturation will be assessed. Due to clinical reasons patients will receive NO (15 ppm) during right heart catheterization. Hemodynamic changes upon NO and Benzbromarone may be compared.

Official Title
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Acute Effects of Benzbromaron on the Pulmonary Circulation

Conditions
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Idiopathic Pulmonary Arterial Hypertension

Intervention / Treatment
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* Drug: Benzbromarone


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: written informed consent known pulmonary arterial hypertension right heart catheterization indicated due to clinical reasons Exclusion Criteria: known allergy against Benzbromaron, Gelborange S or other ingredient of the used drug (Benzbromarone AL) or a drug with similar chemical structure severe renal insufficiency (GFR<30ml/min/kg) renal diathesis severe hepatic disease (Bilirubin >1.6 mg% or AST or ALT > 3x Norm) known pregnancy uncontrolled systemic arterial hypertension (>150 mmHg systolic or 95 mmHg diastolic) uncontrolled ventricular arrythmia uncontrolled bradycardic or tachycardic supraventricular arrythmia myocardiac infarction within the last 12 months pulmonary embolism within the last 6 months ongoing iv. or sc. Prostanoid therapy for PAH Pulmonary hypertension other than PAH

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 90 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Benzbromarone<br>1x200mg Benzbromarone | Drug: Benzbromarone<br>* 1x200mg Benzbromarone will be applied after baseline measurements during right heart catheterization. The effects of the drug on the pulmonary hemodynamics will be assessed after 2 hours.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Pulmonary vascular resistance (Wood units) assessed by right heart catheterization |  | 2 hours | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Mean pulmonary arterial pressure (mmHg) assessed by right heart catheterization |  | 2 hours | 
| Mean systemic arterial pressure (mmHg) assessed by sphygmomanometer |  | 2 hours | 
| arterial oxygen saturation 8%) assessed by arterial blood gas analysis |  | 2 hours |