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.
Normal mean pulmonary arterial pressure ranges from 18 to 22 mm Hg. Pulmonary hypertension is defined as a mean pulmonary artery pressure greater than 25 mm Hg at rest and 30 mm Hg during exercise.
Formerly classified as primary and secondary forms according to the absence or presence of underlying disease. New 2003 classification of the World Health Organization discarded the term primary and secondary (Table 34.1).
Idiopathic and familial forms of pulmonary arterial hypertension
