Trans-Arterial Coil Embolization of the Internal Carotid Artery in Standing Horses

Objectives: To develop transarterial coil embolization (TACE) for occlusion of the internal carotid artery (ICA), in normal standing horses, and to evaluate it use for prevention of hemorrhage in horses with guttural pouch mycosis (GPM). Study Design: Prospective study. Animals: Normal horses (n = 8) and 5 with GPM. Methods: Horses had TACE of the ICA in standing position under fluoroscopic guidance. Four normal horses were euthanatized 2 weeks after TACE for morphologic assessment and 4 were followed for 6 months. The 5 clinically affected horses were evaluated for long-term (10-12 months) success rate and complications. Results: No complications related to the TACE were noted. Up to 30 mL warmed meglumine ioxithalamate was injected and well tolerated. Standing angiography confirmed complete occlusion of all vessels, and coils were positioned as intended; the procedure did not alter local hemodynamics. At 2 weeks, maturing to mature continuous thrombi was seen at the site of the coils. Two clinically affected horses died at day 3 and 12 after surgery from other problems. In the 3 surviving horses, mycotic lesions completely resolved without additional treatment. Conclusions: TACE under fluoroscopic guidance in standing horses provided a safe, minimally invasive, and effective method for ICA occlusion and should be recommended for individuals at risk of general anesthesia. Residual neurologic deficits are a common sequela, but they do not reflect a treatment failure.