Percutaneous ultrasound-guided arterial angiography for transarterial coil placement in anesthetized and standing horses.

OBJECTIVE: To (1) describe ultrasound-guided percutaneous introduction of a transarterial angiographic catheter into the common carotid artery (CCA); (2) investigate the feasibility of using angiography of the carotid arteries in the guttural pouch region and assess transarterial coil (TAC) placement into the internal carotid artery (ICA). STUDY DESIGN: Experimental study. ANIMALS: Healthy Standardbred horses (n = 6), aged 5-8 years. METHODS: Six horses had ultrasound-guided percutaneous CCA catheterization and angiography under general anesthesia. Catheterization sites were ultrasonographically evaluated postoperatively. Ten weeks later using the same horses sedated and standing, the same procedure was combined with placement of a TAC in the ICA. RESULTS: Agitated contrast ultrasonography confirmed successful catheterization of the CCA. Needle puncture and introducer-set penetration of the CCA were the main technical difficulties. Radiography and fluoroscopy confirmed successful angiography and TAC placement. Mild hematoma formation was recorded in 4 of 12 procedures. CONCLUSION: Angiography and TCA placement in the ICA can be safely performed using a percutaneous approach to the CCA under ultrasound guidance, in standing or anesthetized horses. This approach might be used for TAC embolization procedure; however, technical difficulties and hematoma formation can impair the procedure.

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.