Understanding the Role of Calcium in Stent Strut Malapposition: An OCT Analysis

By Alistair C. Lindsay, MD, PhD

Stent strut malapposition is a risk factor for stent thrombosis and restenosis, ultimately leading to higher rates of recurrent clinical events in patients undergoing percutaneous coronary intervention (PCI).  While intravascular ultrasound (IVUS) has traditionally been used to assess stent deployment, more recently optical coherence tomography (OCT) — a novel intracoronary diagnostic technique with an axial resolution approximately ten times greater than IVUS (approximately 10-20 μm) — has been used to provide improved detection of stent malapposition (see figure below).  A further unique feature of OCT is the ability to image through calcium and thus measure the thickness of superficial calcification which may affect stent deployment.

Lindsay fig 3

Legend: Semi-automated quanitification of strut malapposition using a novel software package (Odierna v.2.2, Department of Cardiovascular Diseases, Division of Imaging and Cardiovascular Dynamics, Catholic University Leuven, Leuven, Belgium).  By drawing an automated contour around the lumen (image A), the software is then able to give precise measurements on the malapposition distance between the vessel wall and each individual stent strut (image B).

However, OCT remains a relatively new technique, and to date does not have sufficiently large and prolonged follow-up data to correlate the imaging findings with clinical events that are now relatively rare in the era of second-generation DESs and optimal anticoagulation therapy. Nonetheless, it is logical to propose that poor stent expansion, gross strut malapposition and distortion, and protruding plaques and thrombus — as assessed by OCT — are ominous signs that should be avoided and corrected if feasible and safe to do so.  The aim of this study was to investigate the relationship between OCT-determined plaque and vessel characteristics and stent strut malapposition in a consecutive series of patients undergoing PCI.

Plaque characteristics — including the extent and depth of calcification — were measured for 23 patients, and the number of malapposed struts following final postdilatation was quantified. Both patient and lesion characteristics associated with malapposition were assessed using univariate and multivariate analyses. The mean lesion length was 25.2 ± 10.8 mm, with a minimal lumen area (MLA) of 2.2 ± 1.2 mm2; eight percent of all stent struts were malapposed.  By univariate analysis, the percentage of malapposed struts was found to correlate with the circumferential extent of calcification (P=.04) but no correlation was seen with the depth of calcification. Using multivariate analysis, the circumferential extent of vessel wall calcification was the only plaque feature seen on OCT that correlated with the percentage of malapposed struts (P=.01).

This study highlights the benefits of using OCT to assess atherosclerotic plaque prior to stent deployment, and shows that the circumferential extent — rather than the depth — of calcium appears to correlate with the risk of stent strut malapposition.  In such calcified lesions, OCT can also be used to ensure optimal strut apposition after optimal post dilatation.  Ongoing work aims to establish the relationship between OCT findings at stent implantation, and subsequent clinical and angiographic outcomes.

Read full article: Predictors of Stent Strut Malapposition in Calcified Vessels Using Frequency-Domain Optical Coherence Tomography /  Alistair C. Lindsay, MD, PhD1, Manuel Paulo, MD1, Kilickesmez Kadriye, MD1, Rodrigo Tejeiro, MD1, Eduardo Alegría-Barrero, MD, PhD1, Pak Hei Chan, MD1, Nicolas Foin, PhD2, Dimitris Syrseloudis, MD1, Carlo Di Mario, MD, PhD1 / J INVASIVE CARDIOL 2013;25(9):429-434

OCT, PlaquRelated articles:

Ae-Young Her, MD, Jung-Sun Kim, MD, Yong Hoon Kim, MD, Dong-Ho Shin, MD Byoung-Keuk Kim, MD, Young-Guk Ko, MD, Donghoon Choi, MD, Yangsoo Jang, MD, Myeong-Ki Hong, MD  Histopathologic Validation of Optical Coherence Tomography Findings of Non-Apposed Side-Branch Struts in Porcine Arteries   J INVASIVE CARDIOL 2013;25(7):364-366

The presence of uncovered struts overlying side-branch is considered to be a potential risk of stent thrombosis. This study demonstrates accuracy of optical coherence tomography in detection of neointimal coverage of nonapposed struts over side-branch using a porcine model.

Dennis T.L. Wong, BSc (Med), MBBS (Hons),  Siang Y. Soh, MBBS (Hons),  Yuvaraj Malaiapan, MBBS, MRCPI  /  In-stent Thrombosis Due to Neoatherosclerosis: Insight From Optical Coherence Tomography /  J INVASIVE CARDIOL 2013;25(6):304

This case study highlights the use of OCT in identifying the precise mechanism of the stent thrombosis (neoatherosclerosis or stent apposition?) which helped guide the appropriate intervention.

Aneel Maini, Larisa Buyantseva, MD, Brijeshwar Maini, MD /  In Vivo Lipid Core Plaque Modification With Percutaneous Coronary Revascularization: A Near Infrared Spectroscopy Study  /   J INVASIVE CARDIOL 2013;25(6):293-295

Plaque modification may be performed successfully using interventional methods and can be evaluated with NIRS. Axial plaque shifting is an acute prognostic marker for postprocedure myocardial infarction.

Please visit Dr. Lindsay’s Blog on WordPress: www.alistairlindsay.com

And related articles:

Biasiolli L, Lindsay AC, Chai JT, Choudhury RP, Robson MD. In-vivo quantitative T2 mapping of carotid arteries in atherosclerotic patients: segmentation and T2 measurement of plaque components.  J Cardiovasc Magn Reson. 2013 Aug 16;15(1):69. doi: 10.1186/1532-429X-15-69.

Alegria-Barrero E, Chan PH, Foin N, Syrseloudis D, Tavazzi G, Price S, Lindsay AC, Duncan A, Moat N, Di Mario C, Franzen OW  Concept of the central clip: when to use one or two MitraClips®  EuroIntervention. 2013 Jun 14. doi:pii: 20120403-03. [Epub ahead of print]

Syrseloudis D, Secco GG, Barrero EA, Lindsay AC, Ghione M, Kilickesmez K, Foin N, Martos R, Di Mario C.  Increase in J-CTO lesion complexity score explains the disparity between recanalisation success and evolution of chronic total occlusion strategies: insights from a single-centre 10-year experience.  Heart. 2013 Apr;99(7):474-9. doi: 10.1136/heartjnl-2012-303205. Epub 2013 Feb 2.

Leung CW, Hoffnagle EE, Lindsay AC, Lofink HE, Hoffman VA, Turrell S, Willett WC, Blumenthal SJ.  A qualitative study of diverse experts’ views about barriers and strategies to improve the diets and health of Supplemental Nutrition Assistance Program (SNAP) beneficiaries.  J Acad Nutr Diet. 2013 Jan;113(1):70-6. doi: 10.1016/j.jand.2012.09.018.

Machado MM, Lima ÂS, Bezerra Filho JG, Machado Mde F, Lindsay AC, Magalhães FB, Gama Ida S, da Cunha AJ.  [Characteristics of consultation and mothers’ satisfaction in primary care for children under 5 years of age, Fortaleza, Brazil].  Cien Saude Colet. 2012 Nov;17(11):3125-33. Portuguese.

Lindsay AC, Choudhury RP.  MRI of acute vascular syndromes: the emerging role of cardiovascular MRI in the diagnosis and treatment of AMI and stroke.  Expert Rev Cardiovasc Ther. 2012 Sep;10(9):1101-8. doi: 10.1586/erc.12.65. Review.

Di Mario C, Lindsay AC. Putting the microscope on stent thrombosis.  Heart. 2012 Aug;98(16):1187-8. doi: 10.1136/heartjnl-2012-302294. No abstract available.

Alegría-Barrero E, Foin N, Chan PH, Syrseloudis D, Lindsay AC, Dimopolous K, Alonso-González R, Viceconte N, De Silva R, Di Mario C. Optical coherence tomography for guidance of distal cell recrossing in bifurcation stenting: choosing the right cell matters.  EuroIntervention. 2012 Jun 20;8(2):205-13. doi: 10.4244/EIJV8I2A34.

Lindsay AC, Biasiolli L, Lee JM, Kylintireas I, MacIntosh BJ, Watt H, Jezzard P, Robson MD, Neubauer S, Handa A, Kennedy J, Choudhury RP.  Plaque features associated with increased cerebral infarction after minor stroke and TIA: a prospective, case-control, 3-T carotid artery MR imaging study.  JACC Cardiovasc Imaging. 2012 Apr;5(4):388-96. doi: 10.1016/j.jcmg.2011.10.007.

Lindsay AC, Ferarro M, Franchello A, Barrera Rde L, Machado MM, Pfeiffer ME, Peterson KE. Child feeding practices and household food insecurity among low-income mothers in Buenos Aires, Argentina.  Cien Saude Colet. 2012 Mar;17(3):661-9.

Shah BN, Lindsay AC, Nicol ED. What is the role of accreditation in the era of competency-based specialist training – a perspective from the United Kingdom.  Int J Cardiol. 2012 Oct 4;160(2):79-81. doi: 10.1016/j.ijcard.2012.01.085. Epub 2012 Feb 20.

Alegria-Barrero E, Foin N, Chan PH, Lindsay AC, Di Mario C. Choosing the right cell: guidance with three-dimensional optical coherence tomography of bifurcational stenting.  Eur Heart J Cardiovasc Imaging. 2012 May;13(5):443. doi: 10.1093/ehjci/jes027. Epub 2012 Feb 7. No abstract available.

Cunnington C, Van Assche T, Shirodaria C, Kylintireas I, Lindsay AC, Lee JM, Antoniades C, Margaritis M, Lee R, Cerrato R, Crabtree MJ, Francis JM, Sayeed R, Ratnatunga C, Pillai R, Choudhury RP, Neubauer S, Channon KM. Systemic and vascular oxidation limits the efficacy of oral tetrahydrobiopterin treatment in patients with coronary artery disease. Circulation. 2012 Mar 20;125(11):1356-66. doi: 10.1161/CIRCULATIONAHA.111.038919. Epub 2012 Feb 7.

Joshi FR, Lindsay AC, Obaid DR, Falk E, Rudd JH. Non-invasive imaging of atherosclerosis.Eur Heart J Cardiovasc Imaging. 2012 Mar;13(3):205-18. doi: 10.1093/ehjci/jer319. Epub 2012 Jan 24. Review.

Machado MM, Lindsay AC, Mota GM, Arruda CA, do Amaral JJ, Forsberg BC. A community perspective on changes in health related to diarrhea in northeastern Brazil.  Food Nutr Bull. 2011 Jun;32(2):103-11.

Di Mario C, Iakovou I, van der Giessen WJ, Foin N, Adrianssens T, Tyczynski P, Ghilencea L, Viceconte N, Lindsay AC. Optical coherence tomography for guidance in bifurcation lesion treatment.EuroIntervention. 2010 Dec;6 Suppl J:J99-J106. doi: 10.4244/EIJV6SUPJA16. Review.

Jefferson A, Wijesurendra RS, McAteer MA, Digby JE, Douglas G, Bannister T, Perez-Balderas F, Bagi Z, Lindsay AC, Choudhury RP. Molecular imaging with optical coherence tomography using ligand-conjugated microparticles that detect activated endothelial cells: rational design through target quantification.  Atherosclerosis. 2011 Dec;219(2):579-87. doi: 10.1016/j.atherosclerosis.2011.07.127. Epub 2011 Aug 5.

Lindsay AC, Viceconte N, Di Mario C. Optical coherence tomography: has its time come?  Heart. 2011 Sep;97(17):1361-2. doi: 10.1136/hrt.2010.214825. Epub 2011 Jul 5. No abstract available.

Foin N, Viceconte N, Chan PH, Lindsay AC, Krams R, Di Mario C. Jailed side branches: fate of unapposed struts studied with 3D frequency-domain optical coherence tomography. J Cardiovasc Med (Hagerstown). 2011 Aug;12(8):581-2. doi: 10.2459/JCM.0b013e32834916e3.

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One Response to Understanding the Role of Calcium in Stent Strut Malapposition: An OCT Analysis

  1. Pingback: The Role of Calcium in Stent Strut Malapposition | Dr. Alistair C. Lindsay - Cardiologist

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