Does heparin prophylaxis prevent exacerbations of hereditary angioedema?

Background: Hereditary angioedema (HAE) is a rare disorder characterized by episodes of angioedema of the skin, mucous membranes, and gastrointestinal tract resulting from a defect in the gene that produces C1 esterase inhibitor. Although in vitro laboratory data and past reports suggested that heparin might be efficacious in preventing HAE attacks, no controlled study has been reported to examine heparin's efficacy in this regard.

Objectives: We sought to determine the safety and efficacy of inhaled and subcutaneous heparin versus that of placebo in the prevention of HAE attacks.