Percutaneous Ultrasonography-guided Carotid Artery Stenting without Using a Contrast Medium: Innovation to Reduce Radiation Exposure

Objective: We performed a percutaneous carotid artery stenting (CAS) under ultrasono-graphic (US) guidance without contrast in patients with impaired renal function. We present the CAS procedure, which avoids the simultaneous use of fluoroscopy and US examination, to reduce radiation exposure.Methods: The carotid-stenotic lesion was marked on the skin of the neck based on preoperative US images. The distal protection balloon (DPB) was placed beyond the stenotic portion under fluoroscopy using magnetic resonance angiography and/or plain computed tomography images. The location of the DPB was confirmed by fluoroscopy. Subsequently, the DPB was expanded, and the carotid ultraso-nography confirmed that blood flow was restricted. Thereafter, a stent was placed on the stenotic portion, and the dilatation of the artery was also confirmed by US imaging.Results: Among the six patients (mean age: 78.8 years) included in this study, three asymptomatic and three symptomatic cases were successfully treated using the US-guided CAS technique without complications. The operation time of this technique was similar to that of the conventional method. The average cumulative incident dose (CID) was 64.0 mGy (average CID value of the standard method: 162.4 mGy).Conclusion: Percutaneous US-guided carotid stenting is useful for patients with carotid stenosis and impaired renal function. Avoiding the simultaneous use of fluoroscopy and ultrasonography can reduce radiation exposure for both technicians and patients.