[Expert Insight] Choosing guidewires for antegrade, retrograde approaches during CTO-PCI
Toshiya Muramatsu, MD (Tokyo Heart Center, Tokyo, Japan) explains importance of analyzing CTO anatomy, new CTO guidewires and techniques at COMPLEX PCI 2022
Rapid development and advancement of chronic total occlusion (CTO)-dedicated guidewires and techniques, like the parallel wire technique, are increasing success rates of complex procedures during percutaneous coronary interventions (PCI), an expert said recently.
“CTO guidewire development has been dramatically fast and innovative,” said Toshiya Muramatsu, MD(Tokyo Heart Center, Tokyo, Japan) during a remote presentation at COMPLEX PCI 2022 on Nov 25 at the Grand Walkerhill Seoul in South Korea.
“Recently, the retrograde approach for CTO-PCIs has significantly impacted cases where the antegrade approach had failed,” Muramatsu said. “New techniques and strategies that incorporate the retrograde approach have also advanced CTO-PCIs worldwide.”
CTO, a condition that indicates complete or near complete blockage of one or more coronary arteries, is common in patients with ischemic heart disease. The complexity required to cross the CTO lesion has been associated with worse prognosis and procedural success rates compared to interventions for standard coronary lesions.
Despite the more intricate challenge of CTO-PCIs, advances in device technology and procedural strategies have dramatically increased procedural success rates in recent years.
The most common method of CTO intervention is the antegrade approach (AW), which crosses a guidewire in the direction of natural blood flow. AW is commonly used for less complex cases, like for coronary lesions with clear, tapered proximal cap and short (<20 mm) occlusions.
However, the safety and efficacy of the antegrade approach are limited for more complex occlusions wherein hybrid strategies employing novel techniques such as dissection and re-entry techniques (DART) and the retrograde approach have been reportedly more effective.
The retrograde approach, which crosses the guidewire counter to the natural direction of blood flow (collateral channel) into the distal true lumen, has increased success rates of CTO-PCIs for complex lesions where AW was not effective or feasible. However, the retrograde approach also carries a higher risk of procedural complications.
Both approaches require careful analysis of CTO anatomy and an equally careful selection of CTO guidewires to improve the probability of success, Muramatsu said.
“For the antegrade wire-based approach, anatomy of the CTO lesion can be assessed by the proximal cap, CTO body, and distal cap,” he said. “Anatomy of the proximal cap can be classified by visible microchannels, tapered proximal cap or blunt proximal cap.”
For visible microchannels, Muramatsu suggested using a guidewire with a low penetration force, polymer jacket and tapered tip that allows for transition to an intermediate penetration force wire. For tapered proximal cap, using a guidewire with low penetration force may be followed with an intermediate penetration force wire. For blunt proximal cap, a guidewire with intermediate penetration force may be escalated to a high penetration force wire.
Regarding the CTO body, it was deemed reasonable to continue with the wire used to cross the proximal cap for short lesions (<20 mm) with an unambiguous course. Lesions of long length (>20 mm) with an unambiguous course may necessitate a step down to a low penetration force wire or an intermediate force, non-tapered wire. For distal cap, operators may have to escalate from softer, more steerable wires to a higher penetration force wire, Muramatsu said.
Important structural elements for selecting guidewires included shaft performance (core shaft: 1-piece vs. 2-piece; length), coil structure (rope coil vs. ball tip), tip design (tapered vs. tip coating), tip load (0.3-12 g) and coating type (hydrophilic; slip coating; silicon coating; polymer jacket coating).
Along with the parallel wire technique, Muramatsu explained the retrograde approach for CTOs that requires collateral channel crossing (septal channel classification; epicardial-channel guidewire choice); CTO crossing with IVUS evaluation, the reverse controlled antegrade and retrograde tracking (r-CART) technique and knuckle-wire plus guide extension method; and subintimal stenting.
Selection of channel tracking guidewires – septal or epicardial – depend on whether the channel is straight, tortuous, acute bent or invisible.
|Channel Tracking Guidewires|
|Straight||SION (Asahi Intecc)
SUOH 03 (Asahi Intecc)
|SUOH 03 (Asahi Intecc)|
|Tortuous||SUOH 03||Suoh 03
SION black (Asahi Intecc)
|Acute bent||SUOH 03
SION black (Asahi Intecc)
|SUOH 03 SION black|
|Invisible||FIELDER XT-R (Asahi Intecc)
|Source: Muramatsu slides at COMPLEX PCI 2022|
Regarding channel connection guidewires, both the antegrade and retrograde approaches may be employed in a hybrid strategy that escalates wires on the antegrade side (FIELDER XTR → Asahi Gaia 1st → Asahi Gaia 2nd → guidewire-induced coronary perforation) and uses connection guidewires and r-CART on the retrograde side (Asahi ULTIMATEbros 3 → SION black → knuckle wiring with SION black → (r-CART) externalization with Asahi RG3).
Do-Yoon Kang, MD
Asan Medical Center, Korea (Republic of)