Study Explores Procedural Success, Failure of Hybrid Approach to PCI in Chronic Total Occlusions

More than 9 in 10 patients with chronic total occlusion (CTO) can be successfully treated using a “hybrid” approach to PCI, reports a US registry study published online February 2, 2015, ahead of print in Catheterization and Cardiovascular Interventions.

“The hybrid approach to CTO PCI uses 4 key angiographic characteristics (proximal cap ambiguity, lesion length, quality of distal vessel, and presence of satisfactory ‘interventional’ collaterals) to determine the optimal initial CTO PCI strategy,” Emmanouil S. Brilakis, MD, PhD, of Dallas VA Medical Center (Dallas, TX) and colleagues write. “If the initial crossing strategy does not lead to satisfactory progress, early switch to alternative strategies, techniques, and equipment is recommended.”

Researchers focused on 380 hybrid CTO PCI cases conducted at 4 high-volume centers in the United States between January 2012 and September 2014. Data were collected prospectively and retrospectively as part of the Prospective Global Registry for the Study of Chronic Total Occlusion Intervention (PROGRESS CTO).

Failures Driven By Complex Anatomy

Procedural success, obtained in 91.3% of the cohort, was defined as < 30% residual angiographic stenosis with TIMI 3 antegrade flow through the CTO vessel and its major branches in the absence of MACE (in-hospital death, Q-wave MI, clinically driven TVR [either PCI or CABG], cardiac tamponade requiring pericardiocentesis, or stroke as a result of the procedure).

Between the 347 patients with successful CTO PCI and the 33 patients with failed procedures, clinical characteristics such as age, sex, and comorbidity were similar. Yet failed cases involved more challenging angiographic characteristics (table 1).

In all, 23 of the failures (70%) arose from a reason other than complication; five involved less than TIMI 3 flow after crossing, and 21 were the result of inability to cross the lesion. The 10 failures (30%) due to in-hospital MACE included 2 deaths, 4 MIs, 4 cases of tamponade requiring pericardiocentesis, and 1 repeat PCI. No occurrence of stroke was reported. Perforation developed in 12.1% of failed cases and 2.6% of successful cases (P = .019).

Failed procedures also were less efficient than successful CTO PCI, involving higher median values for:

• Contrast use (355 vs 235 mL; P < .001)
• Fluoroscopy time (69 vs 38 mins; P < .001)
• Radiation dose—both air kerma (5.2 vs 3.1 Gy; P = .001) and dose area product (400 vs 265 Gy/cm²; P = .003)
• Procedure time (158 vs 105; P < .001)

Antegrade wire escalation was the most common initial crossing technique (62%), followed by retrograde (22%) and antegrade dissection and reentry (16%). Apart from death being more common among patients initially receiving the retrograde approach, the levels of success and complications were similar among the 3 crossing techniques. For 70% of the failed cases, at least 2 different crossing techniques were attempted before failure was declared.

Why Go Hybrid?

According to Dr. Brilakis, the hybrid approach is an improvement on earlier CTO PCI strategies for several reasons. “First, it emphasizes the primary importance of dual injection for CTO PCI,” he told TCTMD in an email. “Second, it utilizes the angiographic characteristics of the CTO to guide selection of the initial crossing strategy. Third, it allows (and encourages) early conversion to an alternative crossing strategy if the initial crossing strategy fails.”

Given that failure is more common in patients with complex anatomy, he advised operators at less experienced centers to start with simpler cases.

Dr. Brilakis also offered several tips for optimizing outcomes of hybrid CTO PCI.

“The simplest and most effective way to avoid complications is to do dual injection in most (if not all) CTO PCI cases,” he explained. “This allows better understanding of the position of the equipment and may prevent perforations or other complications.” Remaining vigilant and adapting to feedback throughout the case are both key, Dr. Brilakis added.

Earlier approaches to CTO PCI emphasized “meticulousness and persistence,” Jeffrey W. Moses, MD, of NewYork-Presbyterian Hospital/Columbia University Medical Center (New York, NY), explained in a telephone interview with TCTMD, whereas the hybrid approach “is a much more rapid-fire technique.” The more flexible strategy paired with advances in imaging that reduce radiation “has given us much more latitude in terms of just trying to get it done in one sitting, with whatever technique works—you shuttle from one to the other,” he said, adding that hybrid CTO PCI originated largely in the United States but is now used elsewhere.

Looking to the Future

Though the hybrid approach appears to raise the odds of success in patients with complex anatomy, “it would be nice if we could refine [the algorithm] a little more” so that the initial crossing technique succeeds without requiring operators to move on to a second-line therapy, Dr. Moses noted.

Better guidewires, specifically the Gaia family (Asahi Intecc; Nagoya, Japan), are “being developed for antegrade…. They have upped the frequency of antegrade treatment certainly in Japan and dropped the retrograde frequency. So the distribution of treatment in this series may change over the next few years,” he suggested.

Dr. Brilakis also cited other devices. “The MultiCross and CenterCross catheter (Roxwood Medical; Redwood City, CA) can substantially enhance guidewire support,” he noted. Additionally, “Threader (Boston Scientific) is a combined balloon and microcatheter that can facilitate crossing of ‘balloon-uncrossable’ occlusions.”

Note: Study coauthor Dimitri Karmpaliotis, MD, is a faculty member of the Cardiovascular Research Foundation, which owns and operates TCTMD.

Source:
Sapontis J, Christopoulos G, Grantham JA, et al. Procedural failure of chronic total occlusion percutaneous coronary intervention: insights from a multicenter US registry. Cath Cardiovasc Interv. 2015;Epub ahead of print.

Disclosures:

• Dr. Brilakis reports receiving honoraria/speaking fees from Abbott Vascular, Asahi, Boston Scientific, Elsevier, Somahlution, St. Jude Medical, and Terumo as well as research grants from Guerbet and Infraredx. His spouse is an employee of Medtronic.
• Dr. Moses reports minor consulting for Abbott and Boston Scientific.

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