Download Application of Coronary OCT in Clinical Practice

Application of Coronary OCT in Clinical Practice
Imaging of the coronary arteries is a standard component of percutaneous coronary
interventions (PCI) to guide optimal PCI strategies and stent deployment.1
Intravascular ultrasound (IVUS) is the most commonly used intracoronary imaging
technique.2 IVUS has demonstrated a reduction in repeat revascularization and
restenosis compared to PCI guided by angiography alone.2 Moreover, a recent metaanalysis of more than 19,000 patients showed that IVUS-guided coronary drug-eluting
stent (DES) implantation was associated with a reduced incidence of death, major
adverse cardiac events and stent thrombosis.3
OCT is a visual analog of IVUS in that it uses near-infrared light instead of sound waves
to image the wall of the coronary artery. Both imaging modalities allow physicians to
acquire images of diseased vessels from inside the artery, providing information on
lesion length, vessel diameter, plaque morphology and stent-vessel wall apposition.
OCT is capable of evaluating the cross-sectional and three-dimensional microstructure
of blood vessels at a resolution of approximately 10 μm4 while the resolution afforded by
IVUS is approximately 150 μm.5 The superior resolution of the OCT imaging allows
physicians to better visualize important vessel characteristics and select the most
appropriate treatment.
Overall, OCT and IVUS demonstrate a strong correlation across the parameters most
relevant to PCI guidance, i.e., lumen border, diameter and area measurements. Bezerra
et al.6 reported equivalence between FD-OCT imaging and IVUS to determine coronary
reference lumen dimensions, an important metric used in routine PCI. Yamaguchi T et
al.7 performed a direct comparison of IVUS and OCT in the setting of PCI for coronary
artery disease. The procedural success rates of OCT and IVUS, defined as successful
acquisition of a pullback image, were not statistically different for the two techniques.
There were no major complications with either technique. Some transient events, such
as chest discomfort, brady- or tachycardia or ST-T changes were seen with both
techniques, all of which resolved immediately after the procedure. Minimal lumen
diameter and minimal lumen area measured by OCT were significantly correlated with
the corresponding IVUS measurements, r = 0.91 and 0.95, respectively. Poor visibility of
the lumen border was noted in 17 IVUS procedures (17.3%), compared to 6 OCT
procedures (6.1%).
The OCT technology has evolved from time-domain OCT (TD-OCT) to frequencydomain OCT (FD-OCT) with non-occlusive imaging. The main difference between TDOCT and FD-OCT systems is that FD-OCT systems are capable of much higher
speeds, facilitating rapid, three-dimensional pullback imaging during the administration
of a non-occlusive flush of an optically transparent media or radiocontrast. 4
This document and all applicable downloads are available at www.SJMprofessional.com/OCTreimbursement.
OCT has been used for many years as a research tool and has accumulated more
than 600 publications. This vast body of literature shows an acceptable safety profile
with no significant safety issues reported.4 OCT has also been incorporated as an
outcome measurement technique in multiple studies of new drug-eluting stents.
However, FD-OCT with non-occlusive imaging is now being used routinely to guide PCI
due to its ability to show precisely how the stent is positioned against the artery wall.
This indication is not a research tool—physicians are routinely using FD-OCT for the
same indications as IVUS, specifically to determine:
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Assessment of stent under expansion
Need for additional stent
Stent malapposition
Presence of thrombus
The following literature focuses on the specific clinical application of OCT for guiding
PCI in the clinical catheterization lab:
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Stefano et al.8 described how OCT was incorporated into a US cardiac
catheterization lab based on a specific quality initiative by participating hospitals.
During a 3-month period, all patients undergoing PCI were expected to have OCT; a
total of 150 patients (155 target vessels) participated. Outcomes included safety,
OCT success and impact on management. OCT was performed either prior, during
or after the intervention itself. OCT parameters recorded included luminal diameters
and post-PCI edge dissection. No adverse events were reported, and successful
imaging was reported in 85.7% of target vessels; failed imaging was related to the
severity of stenosis, or inability of the catheter to reach the target legion. OCT
prompted a change in patient management in 81.8% of the patients when used prior
to PCI and in 54.8% when used post-intervention. Management changes when OCT
was used prior to the PCI included the number of stents, stent length or diameter.
Changes following PCI included further stenting, further dilation of an under
expanded stent, or balloon dilation for stent malapposition. This study demonstrated
that similar to IVUS, OCT provided information that directly impacts PCI procedures.
As noted by the authors, “FD-OCT is safe, can successfully be incorporated into
routine practice, and alters procedural strategy in a high proportion of patients
undergoing PCI.”
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Prati F et al.9 compared PCI guidance using angiography and OCT (n=335) with
matched patients undergoing PCI using angiographic guidance alone (n=335). The
primary endpoint was the one year rate of cardiac death or myocardial infarction.
Similar to the Stefano study above, this study demonstrated that OCT can be used
to direct PCI decisions, specifically regarding the need for additional stents, stent
underexpansion or stent malapposition. Findings from the OCT led to additional
interventions in 34.7% of subjects. The authors concluded that OCT can be safely
performed to guide routine PCI and that OCT identifies additional procedural
interventions not recognized by angiography leading to additional interventions in
one third of the patients.
This document and all applicable downloads are available at www.SJMprofessional.com/OCTreimbursement.
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Viceconte N et al.10 reported on 108 consecutive patients who underwent OCT as
an adjunct to PCI. Similar to the Stefano study, OCT was performed before or after
the stenting itself. When performed prior to the stenting to evaluate candidacy for
stenting an intermediate lesion, OCT resulted in a deferral of the procedure itself in
19.1%; when performed after dilation and just prior to stenting, OCT resulted in a
change in management in 52.2% of patients. Finally, when performed after initial
stent deployment, OCT suggested additional stenting in 14% of patients and
further dilation in 30%. The authors concluded that repeated examinations with
OCT can be safely used to guide stent selection and improve stent expansion and
apposition.
The published clinical evidence demonstrates the clinical utility of coronary OCT in
PCI, and shows that OCT is a medically reasonable alternative to IVUS for
intravascular imaging. Typically, PCI requiring intravascular imaging utilize only a
single imaging modality and OCT would be utilized in lieu of IVUS, not in addition to
IVUS.
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Levine GN, Bates ER, Blankenship JC, et al. 2011 ACCF/AHA/SCAI Guideline for Percutaneous
Coronary Intervention. Circulation. 2011;124(23):2574-609.
Agency for Healthcare research and Quality. Intravascular Diagnostic Procedures and Imaging
Techniques Versus Angiography Alone in Coronary Artery Stenting: Comparative Effectiveness
Review. February 26, 2013.
Zhang Y, Farooq V, Garcia-Garcia HM, et al. Comparison of intravascular ultrasound versus
angiography-guided drug-eluting stent implantation: a meta-analysis of one randomised trial and ten
observational studies involving 19,619 patients. EuroIntervention. 2012;8(7):855-65.
Tearney GJ, Regar E, Akasaka T, et al. Consensus standards for acquisition, measurement, and
reporting of intravascular optical coherence tomography studies. J Am Coll Cardiol.
2012;59(12):1058-72.
Nissen SE, Yock P. Intravascular ultrasound: Novel pathophysiological insights and current clinical
applications. Circulation. 2001;103(4):604-16.
Bezerra HG, Attizzani GF, Sirbu V, et al. Optical coherence tomography versus intravascular
ultrasound to evaluate coronary artery disease and percutaneous coronary intervention. JACC
Cardiovasc Intv. 2013;6(3):228-36.
Yamaguchi T, Terashima M, Akasaka T, et al. Safety and feasibility of an intravascular optical
coherence tomography image wire system in the clinical setting. Am J Cardiol. 2008;101(5):562-7.
Stefano GT, Bezerra HG, Mehanna E, et al. Unrestricted utilization of frequency domain optical
coherence tomography in coronary interventions. Int J Cardiovasc Imaging. 2013;29(4):741-52.
Prati F, Di Vito L, Bionid-Zoccai G, et al. Angiography alone versus angiography plus optical
coherence tomography to guide decision-making during percutaneous coronary intervention: The
Centro Per la Lotta Control L-Infarto-Optimisation of Percutaneous Coronary Intervention (CLIOPCI) study. EuroIntervention. 2012;8(7):823-9.
Viceconte N, Chan PH, Barrero EA, et al. Frequency domain optical coherence tomography for
guidance of coronary stenting. Int J Cardiol. 2013;166(3):722-8.
This document and all applicable downloads are available at www.SJMprofessional.com/OCTreimbursement.