Ameroid Band Constrictor-Induced Arterial Occlusion Simulates Peripheral Vascular Disease in a Porcine Model

Introduction: Gradually tightening vascular occluders such as ameroid constrictors are used to model chronic ischemia and may recapitulate human ischemic disease pathophysiology and atherosclerotic plaque progression better than acute ligation. Ultrasonic power Doppler (US-PD) imaging uses Doppler sampling and filtering techniques that significantly increase the sensitivity and specificity of routine sonographic instruments for imaging spatially disorganized patterns of peripheral perfusion without contrast enhancement.
Objective: To compare sensitivity of US-PD with dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) techniques for measuring endothelial function and determining vascular perfusion.
Methods: Four 6-month-old, castrated male, Yucatan minipigs were operated. A~9 cm incision was made in the skin and subcutaneous tissues of the right hindlimb from the inguinal ligament toward the stifle, preserving the femoral artery and vein. The superficial femoral artery was isolated using blunt and sharp dissection, and a 3.5 mm ameroid band constrictor was placed proximally. A single interrupted suture of 3-0 PDS was placed through the pectineus fascia and lumen of the ring to secure the ring proximally and prevent slippage distally. The surgical wound was closed in 3 layers. Animals were imaged by US-PD and DCE-MRI at 1,2,3, and 4 weeks following ameroid placement.
Results: All pigs recovered from anesthesia and healed from surgery without incident. Flow through the superficial femoral artery was substantially decreased by 3-4 weeks in all pigs, however, DCE-MRI revealed minimal decreases in muscle perfusion. Prior to euthanasia, all pigs were injected with fluorescent microspheres, and arterial blood samples were obtained. Following euthanasia, muscle samples were harvested and processed to determine tissue fluorescence density (TFD) which is proportional to the number of spheres trapped in tissue capillaries.
Conclusion: Ameroid constrictors provide gradual occlusion of arteries and can be reliably used in translational studies using animal models designed to mimic chronic progressive vascular occlusion.