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Evaluation of a percutaneously controlled hydraulic occluder in a rat model of gradual venous occlusion
Colin W Sereda1, Christopher A Adin, Pamela E Ginn
1Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32610-0126, USA.
Insights
This study shows that hydraulic occluders (HOs) can achieve gradual venous occlusion in rats over 8 weeks. However, the model
Area of Science:
- Vascular surgery
- Animal models
- Medical device development
Background:
- Gradual venous occlusion is crucial for managing conditions like congenital portosystemic shunts.
- Percutaneously controlled devices offer potential for precise vascular interventions.
Purpose of the Study:
- To assess the efficacy of a hydraulic occluder (HO) for achieving gradual occlusion of the caudal vena cava (CVC) in a rat model.
- To establish a preclinical model for evaluating devices aimed at managing venous abnormalities.
Main Methods:
- An experimental study was conducted on ten male Sprague-Dawley rats.
- Hydraulic occluders and ultrasound flow probes were implanted on the CVC.
- Group I rats (n=6) underwent gradual HO attenuation over 8 weeks; Group II (n=4) served as a control.
Main Results:
- Significant reduction in CVC blood flow was observed in Group I rats, decreasing from 40.71 mL/min/kg to 4.68 mL/min/kg by 8 weeks (P=.0094).
- Complete CVC occlusion was confirmed in all Group I rats post-study.
- Three rats experienced premature occlusion due to device kinking, highlighting a limitation.
Conclusions:
- Gradual occlusion of the CVC was successfully achieved using HOs in a rat model over an 8-week period.
- The study highlights limitations related to animal size and implant dimensions for this specific model.
- Hydraulic occluders show promise as a method for gradual occlusion of congenital portosystemic shunts.
Objective:
To evaluate the efficacy of a percutaneously controlled hydraulic occluder (HO) in a rat model of gradual venous occlusion.
Study Design:
Experimental study.
Animals:
Ten male Sprague-Dawley rats.
Methods:
HOs and perivascular transit time ultrasound flow probes were applied to the caudal vena cava (CVC). Occluders in group I rats (n=6) were gradually attenuated over 8 weeks, whereas occluders in group II rats (n=4) were not attenuated. Vena caval blood flow measurements were performed weekly in all rats for 8 weeks. After euthanasia, the CVC was evaluated grossly and by histopathology.
Results:
Premature occlusion of the vena cava occurred during the 1st week in 3 rats (1 in group I, 2 in group II) because of kinking of the vena cava between the HO and the flow probe. For the remaining rats, mean blood flow in group I decreased significantly from 40.71 mL/min/kg at baseline to 4.68 mL/min/kg at 8 weeks (P=.0094, power=0.91). Group II rats maintained vena caval blood flow at all times during the study. Complete occlusion of the vena cava was confirmed at necropsy in all group I rats.
Conclusions:
Gradual occlusion of the CVC of rats was achieved with HOs over 8 weeks. This model is limited by the size of the experimental animals and comparatively large implants.
Clinical Relevance:
HOs may provide a method for gradual occlusion of congenital portosystemic shunts.