A Novel Technique for Mitigation of the Ledge Effect Caused by the Use of a Large-Lumen Catheter during Neurointervention: Beanstalk Method

Navigating a large-caliber catheter into the intracranial artery may generate a “ledge effect,” which disturbs successful neurointervention. Particularly, navigation of a large-lumen aspiration catheter is often required to achieve fast recanalization in acute ischemic stroke cases. Occasionally, the aspirator cannot be passed through the ophthalmic artery origin because of the ledge effect. Here, we report a new technique for mitigation of the ledge effect that involves the use of double micro-guidewires (MGWs). We refer to this technique as the “beanstalk method.” We evaluated the efficacy of our idea using a silicon vascular model. Two 0.014” MGWs are used for navigation of a 0.068” aspirator. After one guidewire is navigated to the distal portion, another MGW is advanced along with the former guidewire, in a spiral fashion, similar to the growth of a beanstalk. The aspirator can then pass with the coaxial double-guidewire, although there is a severe gap in the vessel. We performed an in vitro study to demonstrate the effectiveness of the beanstalk method. The beanstalk method was very useful, even under challenging conditions that did not allow for passage of a conventional coaxial catheter or buddy-wire. The beanstalk method effectively decreases the ledge effect because of the shape of the two wires just ahead of the catheter, which contrasts with the hardness of the spiral wires. In cases involving challenging vasculature, the beanstalk method achieves smoother catheter navigation than the conventional coaxial method or buddy-wire technique.