Introduction
The introduction of extraplaque dissection techniques in chronic total occlusion (CTO) percutaneous coronary interventions has substantially improved success rates. In antegrade dissection/re-entry (ADR) strategies, the guidewire intentionally advances extraplaque into a dissection plane before re-entering the distal vessel lumen at, or beyond the distal cap [1].
Older techniques like subintimal tracking and re-entry and limited antegrade subintimal tracking, havemostly been abandoned, except for the bailout and so-called “investment” procedures. The anterograde fenestration and re-entry (AFR) technique is limited because it is prone to forming a big subintimal hematoma [2]. Stingray-based ADR is limited by high procedural costs, the need for proctored training, and a relatively high rate of failure [3, 4]. Recross-based ADR is also limited by the steep learning curve, cost, and harder deliverability of the device.
A novel wire-based procedure from extraplaque to intraplaque re-entry technique, dubbed “stiff wire scratching to fenestration, de-escalation, and re-entry technique” (SSDR) is hereby described.
Method
In both anterograde or retrograde wire escalation techniques (AWE, RWE) techniques, if the wire exits extraplaque, the strategy usually switches to ADR or retrograde dissection and re-entry (RDR). Reentry then becomes the most challenging step in the technique. The SSDR technique is an alternative option to ease reentry in such cases is described as follows.
The microcatheter is progressed over the extraplaque wire to a point immediately preceding the anterograde or retrograde cap. Then the wire is exchanged for a stiff wire (eg. Gaia second or third/ConfianzaPro12/Hornet14/Warrior/InfiltracPlus/Judo6). Wire configuration is made prior to insertion through the microcatheter. The operator moves the stiff wire back and forth, repeatedly, with changing wire rotation until completing a 360° circle. Depending on the anatomy of the vessel, the stiff wire can be progressed in variable lengths into the target, usually around 10–40 mm. This foramination maneuver creates multiple micro connections between the extraplaque and intraplaque space. Wire knuckling should be prevented from the beginning because it would further expand the dissection. Since stiff wires are difficult to control and redirect, the operator should not try to track the target vessel lumen with the perforating stiff wire. Instead, the stiff wire in the SSDR technique is exchanged for a low or intermediate-tip load polymer-jacketed wire, like Fielder XT-A/Pilot 200/GladiusEX, keeping the microcatheter in place. This de-escalation improves the free movement of the wire and facilitates a smooth and harmless reentry into the target true lumen (Fig. 1).
The reentry occurs mostly by chance, after repeated careful attempts changing the rotation of the tip, until the wire finds the right micro-connection by chance. After pushing forward the polymer jacketed wire into the target vessel, the distal wire position should be checked with contralateral injection and simultaneous movement of the wire to reassure the distal luminal position (Fig. 2).
Discussion
In cases of ADR or RDR strategies, the SSDR technique is an interesting alternative to ease reentry into the true lumen. Among the assets of SSDR, we could highlight its technical simplicity, and its time- and cost-efficiency, especially if compared with device-based techniques. In most cases, it just demands one additional wire without further expenditure on dedicated devices. Therefore, it could be proposed as a default reentry strategy after switching to dissection-reentry techniques, because other reentry techniques, like Stingray/Recross/AFR definitely consume much more time and resources than this uncomplicated alternative.
Limited antegrade subintimal tracking technique [5], as originally described, starts after the guidewire advancement in the subintimal/extra plaque plane. Guidewires are mostly advanced in the knuckle fashion and followed by microcatheter distal to the distal cap. Then a stiff-tip, highly penetrating guidewire (like Confianza Pro 12) with a steep curve is used for reentry into the distal true lumen. In SSDR micro connections are made with the stiff wire between the extraplaque and intraplaque plane, mostly inside the CTO body. The microcatheter is not moved forward from the initial position, and the wires were not in the knuckle position, therefore the chance for extraplaque hematoma formation is greatly reduced.
In case of SSDR failure, the abovementioned reentry techniques can still be tried without penalty and eventually the switch to retrograde or antegrade strategies in the hybrid approach also remains a bailout option.
Caution is needed due to the risk of perforation with stiff wires. The technique is most suitable in straight CTO segments, whilst it can be problematic in tortuous segments. A key element for success is minimizing unnecessary wire manipulation at the distal target, thus mostly perforating within the CTO segment and a short part of the target. Maneuvers potentially resulting in expansion of the intramural hematoma, like antegrade contrast injection or excessive progression of the microcatheter before reentry should be also avoided.
Conclusions
Stiff wire scratching to fenestration, de-escalation, and the re-entry technique is an interesting alternative technique for lumen reentry in ADR or RDR strategies, which due to its simplicity, as to its time- and cost-efficiency might be considered the default first step, before attempting other classical techniques that consume more time and resources.
