Placement of a spring filter during interventional treatment of deep venous thrombosis to reduce the risk of pulmonary embolism.
OBJECTIVE
To assess the efficacy of the Spring filter during interventional treatment of deep venous thrombosis in vivo.


METHODS
A model of inferior vena cava thrombosis was used. Part I: The thrombus was treated by the pulse-spray technique (PT) (urokinase 250,000 IU; n=7) or a rotatory basket catheter, Thrombolizer (MT) (activated with compressed air at 7 atm; n=5). Part II: Following placement of a Spring filter, the animal underwent PT (n=5) or MT (n=5). Based on the results of part I, the treatment protocol was modified (PT, urokinase 500,000 IU; MT, compressed air at 8 atm). Embolus volumes trapped by the filter and found in the lungs were calculated and the filtering efficacy quantified.


RESULTS
Part I: Pulmonary emboli (1 to 4 mm in diameter) were observed in 3 animals in the PT group and 1 animal in the MT group, respectively. Median reduction in thrombus volume was 21% and 4% by PT and MT, respectively. Part II: In the PT group, 58% and 100% of the total embolus load was trapped in 2 animals, while the filter failed to trap emboli (1 to 1.5 mm in diameter) in 1 animal. In the remaining 2 animals, no embolus was found trapped by the filter or in the lungs. In the MT group, 55 97% (median 83%) of the embolus load was trapped. Emboli found in the lungs did not exceed 4 mm in diameter.


CONCLUSIONS
Preceding interventional treatment of venous thrombosis with placement of the Spring filter reduced the embolic burden on the lungs.
Hosaka
J
J
Section for Experimental Radiology, Institute for Surgical Research, The National Hospital, Oslo, Norway.
Roy
S
S
Kuroki
K
K
Xian
Z
Z
Kvernebo
K
K
Enge
I
I
Laerum
F
F
D000792:Angiography; D000818:Animals; D004195:Disease Models, Animal; D005260:Female; D005343:Fibrinolytic Agents / Q000008:administration & dosage; D007275:Injections, Intravenous; D011655:Pulmonary Embolism / Q000000981:diagnostic imaging / Q000209:etiology / Q000517:prevention & control*; D013552:Swine; D017131:Thrombectomy / Q000379:methods*; D015912:Thrombolytic Therapy / Q000379:methods*; D016896:Treatment Outcome; D016306:Vena Cava Filters; D014682:Vena Cava, Inferior; D020246:Venous Thrombosis / Q000150:complications / Q000000981:diagnostic imaging / Q000628:therapy*
D005343:Fibrinolytic Agents