An animal model for venous thrombosis and spontaneous pulmonary embolism.

STUDY

DESIGN

An animal model.

OBJECTIVE

To test the natural sequence of venous thrombosis and pulmonary thromboembolism experimentally.

SETTING

Veterans Administration Hospital, USA.

METHOD: In dogs, a venous thrombosis was induced in a isolated segment of the internal jugular vein by a 5 min exposure to sodium morrhuate and then re-establishing venous patency. A tracer, (125)I human fibrinogen, was administered through another vein 1 h prior to the end of each experiment when a blood sample, the venous thrombus, and the lungs were removed. Thrombi were described by age, weight, histology, and fibrin uptake (thrombus to blood radioactivity ratio, g/g). Pulmonary emboli (PE) were identified by autoradiography of lung slices or by microscopic examination of lung sections.

RESULTS

Venous thrombosis developed in all experiments, duration 1-64, median 5 h (n=12). Histologically, younger thrombi were characterized by platelet aggregates surrounded by polymorphonuclear leukocytes (PMN), and uniform fibrin deposit; the older thrombi by platelet ghost cells, fewer PMN leukocytes, and broken fibrin strands and loops (n=6). Pulmonary thromboemboli were imaged as 'hot spots' in six of six experiments in which lung slices were autoradiographed and were identified microscopically in six of six experiments in which lung sections were taken. The number of PE diagnosed microscopically did not correlate with the age of the corresponding thrombus but was directly related to fibrin uptake (n=5, r=0.99, P<0.01).

CONCLUSION

An animal model for venous thrombosis that generates pulmonary thromboembolism has been described.