A rare usually fatal disease most commonly seen in women that is best managed in centres with expertise in pulmonary hypertension.
Presenting symptoms and signs are non-specific and include dyspnoea on exertion, fatigue, and a loud pulmonary component of the second heart sound.
Diagnosis of exclusion. Transthoracic Doppler echocardiography and right heart catheterisation can diagnose pulmonary hypertension. Laboratory tests and imaging studies can rule out known causes of pulmonary hypertension.
General supportive therapy includes oral anticoagulants, diuretics, supplemental oxygen, and digoxin.
Targeted treatment options include parenteral and inhaled prostanoids, oral endothelin receptor antagonists, oral phosphodiesterase type-5 inhibitors, the soluble guanylate cyclase stimulator riociguat, and the selective prostacyclin IP receptor agonist selexipag.
Prognosis is not good, as most patients eventually develop right ventricular failure.
Idiopathic pulmonary arterial hypertension (IPAH) is a disease of the small pulmonary arteries characterised by vascular proliferation and remodelling. It results in a progressive increase in pulmonary vascular resistance (PVR) and, ultimately, right ventricular failure and death.  It is defined by a mean pulmonary arterial pressure >25 mmHg at rest with pulmonary capillary wedge pressure <15 mmHg and PVR >3 Woods units, without a known cause. 
Medical Director, Pulmonary Thromboendarterectomy Program
Department of Pulmonary and Critical Care Medicine
GAH has received speaking and advisory board fees from Bayer Healthcare, the manufacturer of riociguat.
Pulmonary Vascular Program
Department of Pulmonary, Allergy, and Critical Care Medicine
RAD declares that he has no competing interests.
Division of Pulmonary and Critical Care Medicine
Mayo Clinic College of Medicine
MJK declares that he has no competing interests.
Consultant Physician in Respiratory and General Internal Medicine
Sheffield Pulmonary Vascular Disease Unit
Royal Hallamshire Hospital
CE has received reimbursement for attending several conferences as well as lecture fees from Actelion Pharmaceuticals, GSK, and Bayer.
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