Optical Coherence Tomography and Fibrous Cap Characterization

Daniel Chamié, Zhao Wang, Hiram Bezerra, Andrew M Rollins, Marco A Costa, Daniel Chamié, Zhao Wang, Hiram Bezerra, Andrew M Rollins, Marco A Costa

Abstract

The pathophysiology of acute coronary syndromes has long been associated with atherosclerotic plaque rupture. Inflammation, thinning, and disruption of the fibrous cap have been implicated with the final processes leading to plaque rupture, but confirmation of these mechanisms of coronary thrombosis in humans has been hampered by the lack of imaging methods with sufficient resolution to resolve fibrous cap characterization and thickness in vivo. Intravascular optical coherence tomography (OCT) provides images with micron-level axial and lateral resolution, enabling detailed visualization of micro-structural changes of the arterial wall. The present article provides an overview of the potential role of OCT in identifying and characterizing fibrous cap morphology, thickness, and inflammation in human coronary plaques.

Figures

Fig. 1
Fig. 1
Representative cross-sectional images of coronary atherosclerosis by OCT. a, A mild concentric fibrous plaque, characterized by homogenous, signal-rich regions. Lipidic plaques (b, c, and d) are characterized by superficial signal-rich region followed by a drop in signal, as a result of high backscattering and attenuation (asterisks). The fibrous cap can be identified as a homogeneous signal-rich band overlying the lipid-rich core. b, A lipid-rich plaque with thick cap (cap thickness at the thinnest part measured 178 μm). c, A thin-cap fibroatheroma, defined by a thin-cap (46 μm at its thinnest part) overlying a lipid-rich plaque. d, Rupture of the fibrous cap overlying a lipid-rich plaque can be observed
Fig. 2
Fig. 2
Volumetric method for quantification of fibrous caps. a, A two-dimensional cross-section image depicting a lipid-rich plaque (asterisks). b, After segmenting the entire fibrous cap extension, a color classification scheme is constructed, mapping the whole fibrous cap according to the regional thickness in red (< 65 μm), green (65–150 μm), or blue (> 150 μm). The fibrous cap is segmented in all frames containing a lipid-rich plaque, allowing for real-time volumetric assessment. c, 3-D rendering reconstruction with fly-through of the coronary vessel, demonstrating the thickness quantification mapping of the whole cap. d, Longitudinal view, allowing a broad visualization of longitudinal and circumferential distribution of the thickness of the fibrous cap. The thresholds of fibrous cap thickness used in this representative example were selected according to the current criteria derived from pathology. However, this novel method allows for quantification of fibrous caps to move from a binary question to a continuous variable, changing the concept of finding a single threshold to predict plaque rupture into a more comprehensive assessment of this complex and dynamic structure

References

    1. Falk E. Plaque rupture with severe pre-existing stenosis precipitating coronary thrombosis. Characteristics of coronary atherosclerotic plaques underlying fatal occlusive thrombi. Br Heart J. 1983;50(2):127–134. doi: 10.1136/hrt.50.2.127.
    1. Davies MJ, Thomas A. Thrombosis and acute coronary-artery lesions in sudden cardiac ischemic death. N Engl J Med. 1984;310(18):1137–1140. doi: 10.1056/NEJM198405033101801.
    1. Virmani R, Burke AP, Farb A, Kolodgie FD. Pathology of the unstable plaque. Prog Cardiovasc Dis. 2002;44(5):349–356. doi: 10.1053/pcad.2002.122475.
    1. Virmani R, Kolodgie FD, Burke AP, et al. Lessons from sudden coronary death: a comprehensive morphological classification scheme for atherosclerotic lesions. Arterioscler Thromb Vasc Biol. 2000;20(5):1262–1275. doi: 10.1161/01.ATV.20.5.1262.
    1. Bezerra HG, Costa MA, Guagliumi G, et al. Intracoronary optical coherence tomography: a comprehensive review clinical and research applications. JACC Cardiovasc Interv. 2009;2(11):1035–1046. doi: 10.1016/j.jcin.2009.06.019.
    1. Kolodgie FD, Virmani R, Burke AP, et al. Pathologic assessment of the vulnerable human coronary plaque. Heart. 2004;90(12):1385–1391. doi: 10.1136/hrt.2004.041798.
    1. Virmani R, Burke AP, Farb A, Kolodgie FD. Pathology of the vulnerable plaque. J Am Coll Cardiol. 2006;47(8 Suppl):C13–18. doi: 10.1016/j.jacc.2005.10.065.
    1. Kolodgie FD, Gold HK, Burke AP, et al. Intraplaque hemorrhage and progression of coronary atheroma. N Engl J Med. 2003;349(24):2316–2325. doi: 10.1056/NEJMoa035655.
    1. Burke AP, Farb A, Malcom GT, et al. Coronary risk factors and plaque morphology in men with coronary disease who died suddenly. N Engl J Med. 1997;336(18):1276–1282. doi: 10.1056/NEJM199705013361802.
    1. Little WC, Constantinescu M, Applegate RJ, et al. Can coronary angiography predict the site of a subsequent myocardial infarction in patients with mild-to-moderate coronary artery disease? Circulation. 1988;78(5 Pt 1):1157–1166. doi: 10.1161/01.CIR.78.5.1157.
    1. Mintz GS, Nissen SE, Anderson WD, et al. American College of Cardiology Clinical Expert Consensus Document on Standards for Acquisition, Measurement and Reporting of Intravascular Ultrasound Studies (IVUS). A report of the American College of Cardiology Task Force on Clinical Expert Consensus Documents. J Am Coll Cardiol. 2001;37(5):1478–1492. doi: 10.1016/S0735-1097(01)01175-5.
    1. Thim T, Hagensen MK, Wallace-Bradley D, et al. Unreliable assessment of necrotic core by virtual histology intravascular ultrasound in porcine coronary artery disease. Circ Cardiovasc Imaging. 2010;3(4):384–391. doi: 10.1161/CIRCIMAGING.109.919357.
    1. Nair A, Margolis MP, Kuban BD, Vince DG. Automated coronary plaque characterisation with intravascular ultrasound backscatter: ex vivo validation. EuroIntervention. 2007;3(1):113–120.
    1. Rodriguez-Granillo GA, Garcia-Garcia HM. Mc Fadden EP, et al. In vivo intravascular ultrasound-derived thin-cap fibroatheroma detection using ultrasound radiofrequency data analysis. J Am Coll Cardiol. 2005;46(11):2038–2042. doi: 10.1016/j.jacc.2005.07.064.
    1. Yabushita H, Bouma BE, Houser SL, et al. Characterization of human atherosclerosis by optical coherence tomography. Circulation. 2002;106(13):1640–1645. doi: 10.1161/01.CIR.0000029927.92825.F6.
    1. Jang IK, Bouma BE, Kang DH, et al. Visualization of coronary atherosclerotic plaques in patients using optical coherence tomography: comparison with intravascular ultrasound. J Am Coll Cardiol. 2002;39(4):604–609. doi: 10.1016/S0735-1097(01)01799-5.
    1. Kume T, Akasaka T, Kawamoto T. Measurement of the thickness of the fibrous cap by optical coherence tomography. Am Heart J. 2006;152(4):755. doi: 10.1016/j.ahj.2006.06.030.
    1. Kubo T, Imanishi T, Takarada S, et al. Assessment of culprit lesion morphology in acute myocardial infarction: ability of optical coherence tomography compared with intravascular ultrasound and coronary angioscopy. J Am Coll Cardiol. 2007;50(10):933–939. doi: 10.1016/j.jacc.2007.04.082.
    1. ••Yonetsu T, Kakuta T, Lee T, et al. In vivo critical fibrous cap thickness for rupture-prone coronary plaques assessed by optical coherence tomography. Eur Heart J. 2011.Important study challenging the current paradigm derived from pathology studies by determining the in vivo thresholds of fibrous cap thickness for predicting plaque rupture.
    1. Jang IK, Tearney GJ, MacNeill B, et al. In vivo characterization of coronary atherosclerotic plaque by use of optical coherence tomography. Circulation. 2005;111(12):1551–1555. doi: 10.1161/01.CIR.0000159354.43778.69.
    1. ••Tanaka A, Imanishi T, Kitabata H, et al. Morphology of exertion-triggered plaque rupture in patients with acute coronary syndrome: an optical coherence tomography study. Circulation. 2008;118(23):2368–2373.Fibrous cap rupture can occur at sites with different thickness depending on the trigger stimulus. This observation challenges the current practice of just searching for the thinnest part of the cap, and praises the need for a more comprehensive and volumetric analysis of this complex structure.
    1. •Ino Y, Kubo T, Tanaka A, et al. Difference of Culprit Lesion Morphologies Between ST-Segment Elevation Myocardial Infarction and Non-ST-Segment Elevation Acute Coronary Syndrome An Optical Coherence Tomography Study. JACC Cardiovasc Interv. 2011;4(1):76–82.This study highlights the importance of studying the morphology of fibrous caps. The authors suggest that beyond the determination of fibrous cap dimensions, careful analysis of its longitudinal morphology can relate to clinical presentation in ACS patients.
    1. Rathore S, Terashima M, Matsuo H, et al. In-vivo detection of the frequency and distribution of thin-cap fibroatheroma and ruptured plaques in patients with coronary artery disease: an optical coherence tomographic study. Coron Artery Dis. 2011;22(2):64–72. doi: 10.1097/MCA.0b013e32833e1c36.
    1. Tanaka A, Imanishi T, Kitabata H, et al. Distribution and frequency of thin-capped fibroatheromas and ruptured plaques in the entire culprit coronary artery in patients with acute coronary syndrome as determined by optical coherence tomography. Am J Cardiol. 2008;102(8):975–979. doi: 10.1016/j.amjcard.2008.05.062.
    1. Sawada T, Shite J, Garcia-Garcia HM, et al. Feasibility of combined use of intravascular ultrasound radiofrequency data analysis and optical coherence tomography for detecting thin-cap fibroatheroma. Eur Heart J. 2008;29(9):1136–1146. doi: 10.1093/eurheartj/ehn132.
    1. Libby P, Simon DI. Inflammation and thrombosis: the clot thickens. Circulation. 2001;103(13):1718–1720.
    1. Libby P. Current concepts of the pathogenesis of the acute coronary syndromes. Circulation. 2001;104(3):365–372.
    1. Lendon CL, Davies MJ, Born GV, Richardson PD. Atherosclerotic plaque caps are locally weakened when macrophages density is increased. Atherosclerosis. 1991;87(1):87–90. doi: 10.1016/0021-9150(91)90235-U.
    1. Moreno PR, Falk E, Palacios IF, et al. Macrophage infiltration in acute coronary syndromes. Implications for plaque rupture. Circulation. 1994;90(2):775–778.
    1. Tearney GJ, Yabushita H, Houser SL, et al. Quantification of macrophage content in atherosclerotic plaques by optical coherence tomography. Circulation. 2003;107(1):113–119. doi: 10.1161/01.CIR.0000044384.41037.43.
    1. Tanaka A, Tearney GJ, Bouma BE. Challenges on the frontier of intracoronary imaging: atherosclerotic plaque macrophage measurement by optical coherence tomography. J Biomed Opt. 2010;15(1):011104. doi: 10.1117/1.3290810.
    1. Tearney GJ, Jang IK, Bouma BE. Optical coherence tomography for imaging the vulnerable plaque. J Biomed Opt. 2006;11(2):021002. doi: 10.1117/1.2192697.
    1. MacNeill BD, Jang IK, Bouma BE, et al. Focal and multi-focal plaque macrophage distributions in patients with acute and stable presentations of coronary artery disease. J Am Coll Cardiol. 2004;44(5):972–979. doi: 10.1016/j.jacc.2004.05.066.
    1. Raffel OC, Tearney GJ, Gauthier DD, et al. Relationship between a systemic inflammatory marker, plaque inflammation, and plaque characteristics determined by intravascular optical coherence tomography. Arterioscler Thromb Vasc Biol. 2007;27(8):1820–1827. doi: 10.1161/ATVBAHA.107.145987.
    1. •Ferrante G, Nakano M, Prati F, et al. High levels of systemic myeloperoxidase are associated with coronary plaque erosion in patients with acute coronary syndromes: a clinicopathological study. Circulation. 2010;122(24):2505–2513.Study associating systemic elevation in selective inflammatory biomarkers with specific pathologic alterations of the fibrous cap.
    1. Garcia-Garcia HM, Costa MA, Serruys PW. Imaging of coronary atherosclerosis: intravascular ultrasound. Eur Heart J. 2010;31(20):2456–2469. doi: 10.1093/eurheartj/ehq280.
    1. Kaneda H, Ako J, Terashima M. Intravascular ultrasound imaging for assessing regression and progression in coronary artery disease. Am J Cardiol. 2010;106(12):1735–1746. doi: 10.1016/j.amjcard.2010.08.012.
    1. Chia S, Raffel OC, Takano M, et al. Association of statin therapy with reduced coronary plaque rupture: an optical coherence tomography study. Coron Artery Dis. 2008;19(4):237–242. doi: 10.1097/MCA.0b013e32830042a8.
    1. ••Takarada S, Imanishi T, Kubo T, et al. Effect of statin therapy on coronary fibrous-cap thickness in patients with acute coronary syndrome: assessment by optical coherence tomography study. Atherosclerosis. 2009;202(2):491–497.This study demonstrates the potential of OCT for serially assessing structural changes in the fibrous cap in response to a specific therapy.
    1. Ambrose JA. In search of the “vulnerable plaque”: can it be localized and will focal regional therapy ever be an option for cardiac prevention? J Am Coll Cardiol. 2008;51(16):1539–1542. doi: 10.1016/j.jacc.2007.12.041.
    1. Stone GW, Maehara A, Lansky AJ, et al. A prospective natural-history study of coronary atherosclerosis. N Engl J Med. 2011;364(3):226–235. doi: 10.1056/NEJMoa1002358.
    1. Nadkarni SK, Pierce MC, Park BH, et al. Measurement of collagen and smooth muscle cell content in atherosclerotic plaques using polarization-sensitive optical coherence tomography. J Am Coll Cardiol. 2007;49(13):1474–1481. doi: 10.1016/j.jacc.2006.11.040.

Source: PubMed

Sponsorer og samarbeidspartnere

Medisinsk tilstand

Legemiddelintervensjoner

3
Abonnere