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A ‘hybrid’ strategy that encompasses possible use of antegrade and/or retrograde approaches increases success rates in percutaneous coronary intervention (PCI) for chronic total occlusions (CTOs) due to in-stent restenosis, matching those for de novo CTOs, according to a registry study published online July 4, 2014, ahead of print in Catheterization and Cardiovascular Interventions.

Historically, the authors say, PCI of in-stent CTO “has been challenging, with low technical success rates.” The current paper updates a report presented at the Transcatheter Cardiovascular Therapeutics scientific symposium in October 2013.  

Similar Procedural Results

Rates of both technical success (angiographic evidence of < 30% residual stenosis with restoration of TIMI 3 antegrade flow in the CTO target vessel) and procedural success (technical success with no procedural MACE) were similar between the CTO groups, as were rates of MACE (death, Q-wave MI, recurrent cardiac symptoms requiring repeat target vessel PCI or CABG, cardiac tamponade requiring pericardiocentesis, and stroke; table 1).

Table 1. Procedural Outcomes by CTO Type

Fluoroscopy time, contrast volume, and air kerma radiation dose were also similar between groups.

According to the authors, there are several potential explanations for lower success rates for in-stent compared with de novo CTO PCI reported in previous studies. For example, in-stent lesions tend to be longer and more calcified. Also, the presence of a prior stent could interfere with the ability to advance equipment through the CTO, and restenting may be hindered by trapping of the new stent in the struts of the old one. Moreover, challenging cases may require penetration of the occluded stent and subsequent strut dilatation, “crushing” the prior stents when the new ones are deployed.

Approach Promotes Preparedness, Flexibility

Dr. Brilakis and colleagues say the current study “highlights the positive impact of the ‘hybrid’ algorithm, specifically the ability to promptly change the CTO crossing strategy if the initially selected strategy does not succeed within a reasonable period of time.” They note that dissection/reentry techniques and the retrograde approach were each employed in almost one-third of in-stent cases, “suggesting that use of these novel strategies was critical to achieving high success rates.”

In addition, they point out that the CrossBoss catheter (Boston Scientific; Boston, MA), which was used in 54.4% of in-stent restenosis cases, has been shown in previous studies to be effective in crossing such CTOs.  

In an earlier paper outlining the algorithm and its rationale (Brilakis ES, et al. J Am Coll Cardiol Intv. 2012;5:367-379), Dr. Brilakis and colleagues say “careful study of the target CTO lesion cannot be overemphasized.” They explain that “understanding the vessel course and the presence, quality, and location of collateral vessels can allow rapid adjustments and change of strategies during the procedure and maximizes the likelihood of success.”   

The ‘hybrid’ approach “was developed by a group of high-volume CTO operators and is intended to serve as a guide to planning CTO PCI in a systematic and reproducible way,” study coauthor Dimitrios Karmpaliotis, MD, PhD, of Columbia University Medical Center (New York, NY), told TCTMD in an email.

In-stent CTOs are “the most complex subset of lesions we tackle in interventional cardiology,” he added, “so we need to go into the case with a well-thought-out strategy.”

Matching Technique to the Lesion

In their 2012 paper, Dr. Brilakis and colleagues recommend dual coronary injection to provide optimal visualization of both the proximal and distal vessel as well as collateral circulation. Then, in-depth review of 4 angiographic characteristics helps determine the initial approach:

• Lesion length
• Location and morphology of the proximal CTO cap
• Quality of the distal vessel
• Presence (or absence) of collaterals suitable for a retrograde approach

When an initial antegrade CTO crossing is attempted, lesions less than 20 mm in length are usually best approached with antegrade wiring using increasingly stiffer guidewires, whereas longer lesions call for upfront use of a subintimal dissection/reentry technique, they advise.

In the retrograde technique, a dedicated guidewire and microcatheter are advanced to the true lumen distal to the occlusion via a collateral vessel, facilitating CTO crossing, Dr. Brilakis and colleagues say, adding that the approach may be the most favorable or the only feasible one in certain lesion subsets. It can also be used as a default strategy when antegrade approaches fail.

The point of the ‘hybrid’ approach is to “focus on opening the occluded vessel using all feasible techniques in the most safe, effective, and efficient way,” the CTO experts conclude.

Note: Dr. Karmpaliotis is a faculty member of the Cardiovascular Research Foundation, which owns and operates TCTMD.

 Source:
Christopoulos G, Karmpaliotis D, Alaswad K, et al. The efficacy of “hybrid” percutaneous coronary intervention in chronic total occlusions caused by in-stent restenosis: insights from a US multicenter registry. Catheter Cardiovasc Interv. 2014;Epub ahead of print.

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