Development and Characterization of a Large Animal Model for Iliofemoral Deep Vein Thrombosis Secondary to Chronic Iliac Vein Stenosis.

BACKGROUND

To establish a large animal model of deep venous thrombosis (DVT) secondary to chronic iliac vein stenosis (IVS) that can simulate pathophysiologic processes in humans.

METHODS

IVS models with degrees of stenosis of approximately 30%, 50%, 70%, and 90% were developed in 4 groups of 12 adult goats using a novel controllable ligation technique. Four weeks later, the stenotic lesion was evaluated by digital subtraction angiography (DSA) and optical coherence tomography (OCT), after which iliac vein thrombosis adjacent to the stenosis was induced by balloon blockade combined with thrombin injection. Three days after thrombosis, the process of clinical thrombus clearance was simulated by a rheolytic thrombectomy catheter, and the IVS was corrected by balloon angioplasty and stent implantation.

RESULTS

After controllable ligation, venography revealed IVS degrees of 31.39 ± 3.09%, 48.95 ± 1.24%, 71.34 ± 5.12%, and 89.78 ± 4.66% in the four groups. After 4 weeks, DSA and OCT showed obvious collateral circulation and intimal hyperplasia around stenotic lesions in group 3, which was consistent with the secondary pathological changes in IVS in humans. The iliac veins in groups 1 and 2 remained patent without obvious collateral circulation, while group 4 showed complete iliac vein occlusion with extensive collaterals. Thrombosis was successfully induced in groups 1 and 2, but groups 3 and 4 required repeated thrombin injections and a shortened distance between the two balloons. Clinical thrombus-clearing devices removed most thrombi, and residual stenosis was corrected by balloon angioplasty and stent implantation. OCT confirmed optimal stent apposition.

CONCLUSION

This study developed a caprine model of IVS-related thrombosis, which can facilitate research on the IVS-DVT relationship and the evaluation of thrombectomy devices and specialized stents for IVS.