CTO recanalization by intraocclusion injection of contrast: The microchannel technique

Abstract

Objectives: To assess the utilization of microinjection of contrast for the recanalization of chronic total occlusions (CTO). Background: Microchannels in CTOs have been considered important conduits for CTO crossing, utilizing dedicated guidewires. We postulated that microinjection of contrast immediately distal to the proximal cap of the CTO could identify and enlarge these microvessels, creating a passage for crossing the CTO with a floppy guidewire. Methods: A total of 32 patients with a CTO were treated with this technique. Following few millimetres penetration of the proximal fibrous cap of the occlusion with a dedicated CTO guidewire, the over-the-wire balloon was advanced into the proximal portion of the occlusion, and 50-100 lg of nitroglycerine followed by 1 ml of contrast was gently injected into the occluded segment. Technical success of the microchannel technique was defined as the ability to visualize the distal true lumen with microinjection of contrast and thereafter cross the CTO with a floppy guidewire in the absence of any dissection. Results: Overall, technical success of the microchannel technique was obtained in 20 (63%) with angiographic success in 19. In 12 (37%) cases there was a technical failure because of dissection, and we obtained recanalization of the artery in 7 of these 12 cases with another technique. There was only one case of periprocedural myocardial infarction in an unsuccessful procedure and no major adverse cardiac events or subacute stent thromboses were observed. Conclusions: Microinjection of contrast immediately distal to the proximal fibrous cap of a CTO may be an additional technique to facilitate recanalization of CTO. ' 2008 Wiley-Liss, Inc.

Chronic Total Occlusion Angioplasty in the United States

“…For those CTOs selected for an antegrade approach, the operator should begin with a soft tipped, tapered hydrophilic wire (Fielder XT, Abbott Vascular, Inc., Abbott Park, Illinois) in an effort to traverse the CTO through microchannels. The crossing of a CTO through microchannels can be facilitated by contrast injection into the proximal cap through the end of a balloon or microcatheter (42). If penetration of the proximal cap or access through a microchannel is unsuccessful, progressive wire tip stiffness (3-, 6-, and 9-g wires) should be tried.…”

Crossing CTOs—The tips, tricks, and specialist Kit that can mean the difference between success and failure

“…Microchannels can then be enlarged using an OTW balloon to carefully inject about 50-100 micrograms of nitrates and subsequently 1 ml of undiluted contrast (using a 2.5 ml syringe) [16]. When using this technique, it is critical that the puncture of the proximal fibrous cap is performed with the guidewire tip in as perpendicular fashion as possible, to avoid injecting into the subadventitial space.…”

Toolbox and Inventory Requirements for Chronic Total Occlusion Percutaneous Coronary Interventions

“…A contrast-guided STAR technique uses an injection through a microcatheter pushed inside the proximal occlusion cap to intentionally induce hydrodissection and occasionally hydro-reentry. 18 This technique suffers from the same drawbacks of the STAR technique and is associated with a relatively high risk of complications. …”