Thin film occlusion of an intra‐abdominal vein in cats

Abstract

ObjectiveTo evaluate the occlusion of an intra‐abdominal vessel as a model of an extrahepatic portosystemic shunt by thin film banding in a controlled setting and to document histologically the perivascular region's response to thin film banding after 8 weeks.Study designExperimental study.AnimalsSix purpose‐bred healthy domestic short hair cats.MethodsThin film bands were placed around the external iliac vein, with a sham procedure on the contralateral vessel. Closure rates were monitored via computed tomographic angiography (CTA) every 2 weeks for a total of 8 weeks. After 8 weeks, the vessels were resected, if possible, and submitted for histopathologic evaluation.ResultsAll cats tolerated the procedure without surgical complications. Eight weeks after surgery, closure was evaluated as complete in one cat, marked in two cats, moderate in one cat, and mild in two cats according to CTA. Histological examination (in three cats) was consistent with chronic, multifocal, granulomatous inflammation with moderate fibrosis and collagen degeneration.ConclusionVenous occlusion was inconsistent and often incomplete 8 weeks after thin film banding of the external iliac vein despite the presence of moderate to abundant perivascular fibrous tissue.Clinical significanceVascular occlusion by thin film banding in cats is mainly incomplete after 2 months. This study supports the theory that high level of residual shunting may be expected in some cats after thin film banding.

Surgical treatment and outcome of intrahepatic shunts in 12 cats

“…15,28,29 Some studies report that the use of gradual occlusion techniques, such as cellophane band and ameroid constrictor, may produce faster shunt attenuation than desired. 15,31,32 An experimental study of thin film occlusion of intra-abdominal veins in cats demonstrated immediate complete closure of the intra-abdominal vein in two cats postoperatively and only 50% of cats had marked or complete vessel occlusion after 8 weeks. 32 Another study reported complete failure of the cellophane band to produce shunt closure in one cat.…”

“…15,31,32 An experimental study of thin film occlusion of intra-abdominal veins in cats demonstrated immediate complete closure of the intra-abdominal vein in two cats postoperatively and only 50% of cats had marked or complete vessel occlusion after 8 weeks. 32 Another study reported complete failure of the cellophane band to produce shunt closure in one cat. 20 Use of a thin film band may be unpredictable in cats when it comes to the degree of shunt attenuation it is able to produce.…”

Clinical outcomes for 20 cats with congenital extrahepatic portosystemic shunts treated with ameroid constrictor ring attenuation (2002–2020)

“…Gradual occlusion with these devices reduces the risk of fatal portal hypertension 4,5,9,13 . Some surgeons prefer ARCs over thin film bands because the bands vary in chemical composition, which could affect or limit the cat's inflammatory response to the device 8,14,15,16 …”

“…4,5,9,13 Some surgeons prefer ARCs over thin film bands because the bands vary in chemical composition, which could affect or limit the cat's inflammatory response to the device. 8,14,15,16 There are currently only two published studies, both from 2002, evaluating the long-term outcome for a series of cats with EHPSS attenuated with an ARC, and the results are inconsistent. 4,9 In one study, perioperative complication rates were high (17/22 cats) whereas excellent long-term outcomes were obtained in 15/20 cats.…”