Optical Frequency Domain Imaging for Guidance of Optimal Stenting in the Setting of Recanalization of Chronic Total Occlusion

Abstract: We present an interesting case illustrating how coronary optical frequency domain imaging (OFDI) examination can be used to guide revascularization of a complex chronic total occlusion (CTO) in a patient presenting to our hospital with a 2-year history of angina, dyspnea, and a positive treadmill test. This case demonstrates the potential clinical role of high-resolution OFDI to optimize coronary stent implantation. OFDI may help to limit the coronary area covered by stents to the true coronary lesion. 

J INVASIVE CARDIOL 2013;25(7):367-368

Key words:chronic total occlusion; high-resolution OFDI

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Recanalization of chronic total occlusions (CTOs) is frequently followed by extensive stent implantation of the entire occluded segment, since the occluded segment frequently remains narrowed for some time in response to the chronic lack of coronary flow. Here we present a case that nicely illustrates how optical frequency domain imaging (OFDI) can be used in this clinical setting to optimize and reduce the need of stent implantation for this complex coronary intervention, since OFDI can identify vascular segments that are free from dissection and relevant atherosclerotic disease and therefore will dilate upon adequate restoration of coronary blood flow into the occluded artery. 

Case Report

A 52-year-old male was admitted with a 2-year history of angina (Canadian Cardiovascular Society class 2-3), dyspnea (New York Heart Association class II), and a positive treadmill test. Coronary angiography revealed a proximal CTO of the circumflex artery (Figure 1A; Videos 1-4). A 7 Fr extra back-up guiding catheter was used and an initial bolus of unfractionated heparin (100 IU/kg body weight) was injected to maintain an activated clotting time of ≥250 seconds. The antegrade technique was used to recanalize the occluded coronary artery using a Whisper MS guidewire (Abbott Vascular) with support from a 1.25 mm Avion balloon (Invatec SPA). 

The circumflex artery was subsequently dilated with a 2.0 x 30 mm balloon (Video 2). OFDI was performed to determine the extent of coronary dissection and the length of the segment with stenotic atherosclerotic disease (Figure 1B). Two biolimus-eluting stents (2.75 x 36 mm, distal 2.5 x 18 mm) were implanted according to the determined coronary lesion length (Figure 1C). Postprocedural OFDI revealed no significant dissection or stenotic atherosclerotic disease distal to the stents and demonstrated that the remaining distal narrowing (despite nitrate administration) was not due to a coronary lesion (Figure 1C; Video 3). Control angiography after 3 months revealed the full diameter of the vessel distal to the stents, suggesting a complete reversal of the previous functional adaptation due to the chronic lack of flow (Figure 1D; Video 4).

Discussion

Morphologic features of chronic total occlusion (CTO) have been described by intravascular ultrasound (IVUS) and computed tomography coronary angiography (CTCA).^1,2 OFDI has now become widely available and provides a 10-fold higher resolution as compared to IVUS.³ The length of the segment with dissection or stenotic atherosclerotic coronary disease after recanalization of CTOs is frequently overestimated by angiography due to the narrowing of the chronically occluded segment in response to a chronic lack of flow. OFDI may be particularly useful in adapting the need of stent implantation to the actual requirements, ie, it can avoid unnecessary stent implantation, as nicely illustrated by the present case.⁴ Furthermore, OFDI reveals malapposition of stent struts after stent implantation, which can be immediately corrected by postdilatation. 

OFDI is highly sensitive to detect coronary dissections and plaques, which aids in determining the required stent length. Moreover, OFDI can assure that the wire is distally in the true lumen. However, OFDI needs to be used prudently in this setting, since repeated contrast injections may potentially enlarge the coronary dissection.

We have used the C7-XR OFDI system (LightLab Imaging, Inc/St Jude Medical), which acquires images during intracoronary injection of contrast media with the single-mode optical-fiber DragonFly catheter. The DragonFly catheter was positioned over a 0.019˝ angioplasty guidewire and automated pullback (20 mm/second) and contrast injection (6 mL/s) were used to acquire high-quality images. OFDI can be performed only at high quality when the coronary artery is free of blood, avoiding backscatter from erythrocytes. We therefore started image recording only when intracoronary imaging revealed that the coronary artery was successfully flushed.

The presented case further supports the potential clinical role of high-resolution OFDI to guide catheter-based stent implantation in the setting of recanalization of complex CTO. OFDI allows for precise determination of coronary dissection and lesion length requiring stent implantation, which is frequently overestimated by coronary angiography. 

See videos that accompany this article at "Using Optical Frequency Domain Imaging to Reduce Use of Stents in the Setting of Chronic Total Occlusion."

References

1. Fujii K, Ochiai M, Mintz GS, et al. Procedural implications of intravascular ultrasound morphologic features of chronic total coronary occlusions. Am J Cardiol. 2006;97(10):1455-1462.
2. Rodriguez-Granillo GA, Rosales MA, Llaurado C, Ivanc TB, Rodriguez AE. Guidance of percutaneous coronary interventions by multidetector row computed tomography coronary angiography. EuroIntervention.2011;6(6):773-778.
3. Templin C, Meyer M, Muller MF, et al. Coronary optical frequency domain imaging (OFDI) for in vivo evaluation of stent healing: comparison with light and electron microscopy. Eur Heart J.2010;31(14):1792-1801.
4. King A. Interventional cardiology: new insights into PCI for chronic total occlusion. Nat Rev Cardiol.2012;9(7):372.

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From the ¹Cardiology Department, Cardiovascular Center, University Hospital Zurich, Zurich, Switzerland, and ²Cardiovascular Department, Division of Cardiology, Ospedali Riuniti di Bergamo, Italy.

Disclosure: The authors have completed and returned the ICMJE Form for Disclosure of Potential Conflicts of Interest. Dr Guagliumi is a consultant for St Jude Medical and holds a research grant from Lightlab/St Jude Medical. The authors report no conflicts of interest regarding the content herein.

Manuscript submitted January 2, 2013, provisional acceptance given February 20, 2013, final version accepted April 10, 2013.

Address for correspondence: Ulf Landmesser, MD, Department of Cardiology, University Hospital Zurich, 8091 Zurich, Switzerland. Email: ulf.landmesser@usz.ch