Related video: Dr. Walker on the Transcollateral Approach
In the June issue of Vascular Disease Management, Subramanian and Adams present an excellent review article on utilizing the transcollateral approach to cross, then to interventionally treat, chronic total occlusions (CTOs) that can’t be crossed in standard antegrade manner.
Chronic total obstructions must be crossed to allow interventional treatment success. Antegrade crossing success with standard wires and support catheters varies among operators based on experience, imaging abilities, and persistence. Crossing failure is not uncommon, and complications such as perforation may occur with aggressive attempts.
Dedicated crossing tools and re-entry tools have been reported to improve crossing success but are associated with substantially increased cost and do not universally achieve crossing success. Lesions that can’t be crossed in an antegrade manner can frequently be crossed via retrograde approach. Pedal and popliteal artery access to facilitate retrograde crossing are being utilized more commonly throughout the world. These approaches typically require additional sterile preparation and another vascular entry often into a severely diseased run-off vessel. Overlying skin infection or prior surgical incisions may be problematic and sheath size is often limited to avoid being obstructive.
Transcollateral approach allows retrograde approach to the CTO without an additional entry site. This approach can be utilized to open multiple occluded vessels in a single setting via a standard single antegrade approach. The article by Subramanian and Adams describes practical techniques that can be utilized with transcollateral approach to improve crossing and treatment success with excellent case studies.
Transcollateral approach has afforded crossing success and ultimately successful treatment in many complex cases. All peripheral interventionalists must familiarize themselves with the use of this approach. I have found that aggressive repeated treatment with vasodilators to avoid vascular spasm is crucial. A thorough understanding of guidewires, support catheters, and balloons is essential. Typically, several wire exchanges are needed (flexible wires to negotiate tortuous collaterals followed by more supportive wires to deliver therapy or crossing wires to penetrate and cross the CTOs). Patience is a necessary virtue.