Thin film occlusion of an intra-abdominal vein in cats

To 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.

Experimental study.

Six purpose-bred healthy domestic short hair cats.

Thin 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.

All 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.

Venous 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.

Vascular 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.