Idiopathic and familial forms of pulmonary arterial hypertension
• A mean pulmonary artery pressure greater than 25 mm Hg at rest and 30 mm Hg during exercise, with a normal pulmonary artery wedge pressure and the absence of identifiable causes or risk factors
• One to two new cases per million each year
• Pathophysiology of both idiopathic and familial pulmonary hypertension is poorly understood.
• A hormonal, mechanical, or unidentified insult to the endothelium with an increased susceptibility to pulmonary vascular injury is considered to result in vascular scarring, endothelial dysfunction, and intimal and medial proliferation. As a result, the effective total cross-sectional area of the pulmonary vascular bed is reduced.
• Present with syncope, dyspnea on exertion, chest pain, and right heart failure
• Prognosis remains very poor, with a 5-year mortality rate of 35%.
• Vasodilator therapy with prostacyclin, sildenafil citrate and nitric oxide may be successful.