Hybrid PCI strategy rules for complex CTO

The hybrid algorithm-based PCI strategy utilizes an individual’s CTO anatomy to dictate the initial choice of approach. The goal is to pick the strategy that is most likely to achieve successful outcome efficiently, with minimal contrast and radiation doses for that particular type of CTO. The hybrid algorithm begins with dual-catheter injection and intravascular ultrasound aimed at determining whether four key anatomic features are present: an ambiguous proximal cap, a poor distal target, good interventional collaterals, and a major side branch at the distal cap.

If those four features are absent and the CTO lesion is less than 20-mm long, the algorithm dictates that the initial approach is antegrade wire escalation; if the lesion is 20 mm or more, the first approach is antegrade dissection reentry. However, if those anatomic features are present, the initial strategy is retrograde wire escalation if the lesion is less than 20 mm, and retrograde dissection reentry for longer lesions. When the initial approach fails, structured protocols dictate the selection of second and third approaches (JACC Cardiovasc Interv. 2012 Apr;5[4]:367-79).

The right coronary artery was the site of the CTO in 70% of study participants. Dual-catheter access was utilized in 79% of patients; only 10% had exclusively radial access. An average of 2.8 Synergy stents were deployed, with a whopping mean total stent length of 96.6 mm in the 48% of patients with dissection and 75.4 mm in those without. Mean procedure time was 122 minutes, with a fluoroscopy time of 44.6 minutes.

The primary efficacy endpoint was the rate of target vessel failure (TVF) at 12 months, defined as cardiac death, MI related to the target vessel, or any ischemia-driven revascularization of the target vessel. The rate was 5.24%.

“We were pleasantly surprised by that,” Dr. Walsh admitted.

Indeed, based upon studies of PCI for CTO published by other investigators, he and his colleagues had initially projected a 13% TVF rate, then bumped it up to 15% because of the high degree of lesion complexity.

Diabetes was the main predictor of target vessel revascularization.

At the time of the index PCI, 19% of patients were scheduled to return for an early optimization procedure within 3 months. This was arranged when operators anticipated significant positive remodeling would occur as the target vessel readjusted to blood flow or distal disease of borderline severity was noted beyond the CTO segment. These were not counted as adverse events. Half of the returnees underwent angiography and no further action was undertaken. The others underwent postdilation of their Synergy stents or new stenting of distal disease.

Complete revascularization of the target territory was achieved in 98.6% of patients. Key complications consisted of 5 perforations, 10 hematomas at vascular access sites, 2 cases of pericardiocentesis, and 4 instances of bleeding requiring transfusion.

The final successful CTO revascularization strategy was antegrade dissection reentry in 18% of patients, retrograde dissection reentry in 30%, antegrade wire escalation in 34%, and retrograde wire escalation in 18%. A switch from the initial algorithm-based strategy to a second strategy occurred in 41% of patients, and a third strategy was employed in 9%.