Establishment and preliminary validation of a porcine femoral artery chronic total occlusion-like lesion model induced by combined CaCl2 and FeCl3 treatment

Abstract:

Background and Aims Chronic total occlusion (CTO) lesions in peripheral artery disease (PAD) are characterized by complex pathological changes including thrombosis, vascular remodeling, and calcification. Existing animal models are often unable to simultaneously reproduce these features. This study explored the feasibility of establishing a porcine femoral artery CTO-like lesion model using combined focal treatment with calcium chloride (CaCl₂) and ferric chloride (FeCl₃).Methods One healthy adult white pig was used. The right femoral artery underwent intraluminal CaCl₂ perfusion, FeCl₃-soaked filter paper application, and additional perivascular CaCl₂ injection, while the contralateral femoral artery served as a sham-operated control. Digital subtraction angiography (DSA) and computed tomography angiography (CTA) were performed before modeling and at 2 and 3 months after modeling. Histological changes were evaluated by hematoxylin-eosin (HE) staining at 3 months.Results DSA demonstrated persistent occlusion of the modeled femoral arterial segment at both 2 and 3 months, with small continuous collateral vessels observed in the delayed phase at 3 months. CTA showed severe stenosis or occlusion of the modeled segment, accompanied by intraluminal filling defects and focal high-density shadows on the vessel wall. HE staining revealed thrombus formation and organization, intimal thickening and disruption, disordered arrangement of medial smooth muscle cells, and focal suspected calcium salt deposition-like changes.Conclusion This single-case preliminary feasibility study suggests that combined focal treatment with CaCl₂ and FeCl₃ can induce a CTO-like lesion in the porcine femoral artery, characterized by persistent luminal occlusion and thrombus organization with focal calcium salt deposition-like changes. This method may provide an exploratory approach for constructing large-animal models of lower-limb arterial chronic occlusion, although its reproducibility and stability require further validation.