Role of Vascular Ultrasound in Monitoring Arteriovenous Fistula Changes in Patients on Maintenance Hemodialysis with Buttonhole Cannulation: Two Case Reports.

Buttonhole (BH) cannulation with a blunt needle offers the patient an alternative to the dreaded sharp needle stick. We used ultrasound imaging to track the morphological changes in the arteriovenous fistula (AVF) caused by the BH cannulation in two patients. During the initial stage of the BH cannulation, a protrusion (intimal hyperplasia) was observed in the vessel at the punctured area. With continued BH cannulation, the protrusion vanished naturally. The more parallel the needle puncture angle was to the vessel, the less it caused vessel dilatation; the antegrade puncture might have less vessel dilatation than the retrograde puncture. Ultrasound-based visualization of these dynamic changes facilitates the refinement of the BH cannulation. The ultrasonic tracking of the AVF morphological changes caused by the BH needling merits further investigation and clinical implementation.