Study of Heparin Prophylaxis of Hereditary Angioedema Exacerbations

PROTOCOL ENTRY CRITERIA: --Disease Characteristics-- * Confirmed diagnosis of hereditary angioedema (HAE) based upon C4 antigenic level, positive family history, and C1 inhibitor (C1INH) antigenic level (Type I HAE) or functional level (Type II HAE) * Functional C1 within normal levels if diagnosis of acquired C1INH is possible * Negative family history will not exclude as long as patient meets all other criteria, has normal C1 level, and has no evidence of acquired C1INH deficiency * History of symptoms of HAE including episodic swelling, abdominal pain, and/or respiratory difficulty * Experiencing a minimum of 1-2 HAE episodes within 6 weeks --Prior/Concurrent Therapy-- * Endocrine therapy: Anabolic steroids allowed as long as dose has not been changed in at least 30 days * Other: No concurrent and at least 1 week since prior aspirin, nonsteroidal antiinflammatory agents, dipyridamole, Coumadin-like drugs, or any other medication having an effect on coagulation or platelets --Patient Characteristics-- * Hematopoietic: No clinically significant history of hematologic disease * Hepatic: No clinically significant history of hepatic disease * Renal: No clinically significant history of renal disease * Cardiovascular: No clinically significant history of cardiac disease or hypertension * Pulmonary: No clinically significant history of pulmonary disease * Other: No contraindication to the use of inhaled or subcutaneous heparin No drug allergy that would interfere with the study No clinically significant history of: Malignancy Diabetes mellitus Neurologic disease Immunologic disease Bleeding disorder Infirmity No history of drug abuse, alcoholism, psychosis, or other psychological/psychiatric disorder