709 - Revascularization of Infrapopliteal Chronic Total Occlusions: A Review of Crossing Techniques

Learning Objectives:

1. 
   Review contemporary crossing techniques for infrapopliteal chronic total occlusions.
   
   


2. 
   Highlight the role of emerging devices and adjunctive technologies in overcoming technical challenges.
   
   


3. 
   Provide step-by-step framework for selecting access, technique, and device strategies in complex below-the-knee interventions.
   
   

Background: Infrapopliteal CTOs represent a major cause of critical limb ischemia, particularly in patients with diabetes and renal disease. These lesions are frequently long, calcified, and fibrotic, posing significant challenges to endovascular revascularization. While conventional methods such as antegrade femoral access and wire escalation remain foundational, technical failures often necessitate innovative crossing strategies. A systematic understanding of these approaches is essential for the interventional radiologist managing complex limb salvage cases.

Clinical Findings/Procedure Details: Crossing strategies can be broadly categorized into single-access wire techniques, dual-access hybrid methods, and adjunctive device-based reentry/plaque modification approaches.

Single-access methods include sliding, penetration, and drilling techniques that exploit microchannels within the lesion, as well as knuckle wire and parallel wire techniques that facilitate controlled subintimal passage. The transcollateral approach represents an alternative when antegrade or retrograde access is unsuccessful, utilizing well-developed collaterals for recanalization. In more challenging cases, dual-access approaches such as Controlled Antegrade and Retrograde Subintimal Tracking (CART and reverse CART) or Subintimal Arterial Flossing with Antegrade-Retrograde Intervention (SAFARI) enable through-and-through wire passage and enhance procedural success.

Adjunctive techniques play a critical role in addressing heavily calcified or resistant lesions: the PIERCE method allows direct plaque puncture with a needle, while BADFORM facilitates balloon-assisted reentry into the true lumen. Dedicated reentry devices, such as the Pioneer Plus intravascular ultrasound–guided catheter and the Outback Elite reentry catheter, provide further precision and control.

Conclusion and/or Teaching Points: Crossing infrapopliteal CTOs requires a comprehensive algorithm integrating techniques and emerging devices. The evolution of technologies—including reentry catheters, lithotripsy, and bioresorbable scaffolds—has transformed limb salvage interventions, offering tailored solutions for heavily calcified, long-segment, or complex occlusions.