First Validation of the "Bite-In" Technique for Retrograde Chronic Total Occlusion Revascularization

Failure in manipulating the retrograde guidewire (RGW) or advancing the retrograde microcatheter (MC) is a common challenge in the retrograde approach to chronic total occlusion (CTO). Effective strategies to overcome the limited control of the RGW deformation have not yet been developed.

This study aimed to evaluate the predictive performance of five CTO scoring systems for time-efficient guidewire (GW) crossing.

From May 2024 to June 2025, the "bite-in" technique was employed in 40 out of 60 consecutive patients due to failure of the "tip-in." In this approach, the RGW is first advanced into the Guidezilla catheter, followed by controlled antegrade rotation of the MC to facilitate spontaneous capture of the RGW at the coaxial interface. This technique eliminates the need for active RGW manipulation during this critical step.

The right coronary artery was the most common CTO site (24/40, 60%). The mean J-CTO, PROGRESS, and JR-CTO scores were 2.5 ± 1.0, 0.7 ± 0.7, and 1.5 ± 0.9, respectively. A primary retrograde strategy was employed in 30% of all procedures. The mean duration of the retrograde approach was 111.1 ± 45.6 min. Limited RGW control and failed retrograde MC advancement occurred in 88% and 75% of cases, respectively. Bite-in technical success was achieved in all patients. No procedural complications were adjudicated to bite-in.

The bite-in technique is a feasible and safe method in the retrograde approach to CTO by facilitating connection between the retrograde and antegrade lumens. Larger multicenter studies are warranted to validate its long-term efficacy compared with the tip-in approach, despite its acceptable short-term performance.