OBJECTIVETo evaluate the corresponding influence on pulmonary embolism incidence between immobilization and exercise in different stage of thrombus after acute deep vein thrombosis in rabbits.

METHODSForty-eight New Zealand rabbits were randomly divided into three groups depending on the different organized stage of thrombus: the early, medium and later stage group.Each group was subdivided into two sub groups: the immobile and mobile subgroup. Rabbit modeling of deep vein thrombosis was made by ligating the right femoral vein. Among the early-stage group, rabbits of the immobile subgroup were fixed for 3 days, while that of the mobile subgroup were free to move for 3 days, then each was euthanized to extract the lungs for pathological examination. Among the medium-stage group, each of the immobile subgroup were fixed for 7 days, while the mobile subgroup ones were fixed for 3 days, then released free-moving for 4 days following the pathological extraction. Among the later-stage group, animals in the immobile subgroup were fixed for 14 days comparing the mobile subgroup fixed for 7 days and next free-moving for 7 days, then each was euthanized.

RESULTSAmong the early-stage group, pulmonary embolism incidence (PEI) of the immobile and mobile subgroup was 4/8 vs.3/8, the pulmonary lobe embolism incidence (PLEI) was 17.5% (7/40) vs. 15.0% (6/40). Among the medium-stage group, PEI of the immobile and mobile subgroup was 3/8 vs. 2/8, PLEI was 37.5% (7/40) vs. 25.0% (10/40). Among the later-stage group, PEI of the immobile and mobile subgroup was 3/8 vs. 3/8, PLEI was 12.5% (5/40) vs. 15.0% (6/40). There was no statistical difference between immobilization subgroup and mobilization subgroup among different stage group.

CONCLUSIONOn the premise of given anticoagulation treatment, early ambulation do not significantly increase pulmonary embolism incidence after acute deep vein thrombosis of lower extremity in rabbits.