Chronic pulmonary thromboembolism in dogs treated with tranexamic acid.

BACKGROUND: Many questions remain regarding the pathogenesis, natural history, diagnosis, and treatment of chronic thromboembolic pulmonary hypertension in patients. To answer such questions, we developed an animal model of this disorder. The brisk thrombolytic response of canines to acute embolism has, previously, prevented the establishment of such a model. METHODS AND RESULTS: The fibrinolytic inhibitor tranexamic acid was given orally to canines before, and for intervals after, pulmonary emboli were released from venous thrombi formed in vivo in femoral veins or the inferior vena cava. Preliminary studies disclosed that embolic residuals from femoral vein thrombi were not sufficient to cause significant, persistent pulmonary hypertension. With repetitive, larger thrombi embolized from the inferior vena cava, however, persistent pulmonary hypertension was achieved in most animals. CONCLUSIONS: Resolution of emboli in the canine can be inhibited by tranexamic acid. As in humans, a spectrum of embolic residuals is encountered, and the perfusion lung scan consistently underestimates the extent of embolic residuals. Studies of this animal model continue.

Severe restrictive pulmonary defect in a patient with adult-onset Still's disease.

Adult-onset Still's disease is characterized by seronegative arthritis, fever, and an evanescent skin rash. Earlier reports have described pneumonitis and pleuritis as manifestations of this disease. We report a patient with adult-onset Still's disease with severe restrictive ventilatory impairment and evidence of respiratory muscle weakness who responded to corticosteroid and aspirin therapy.