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Circumferential Strut Fracture as a Mechanism of “Crush” Bifurcation Restenosis
Circumferential Strut Fracture as a Mechanism of “Crush” Bifurcation Restenosis Sulaiman Rathore, MDa, Timothy Ball, MD, PhDa, Masataka Nakano, MDb, Aaron Kaplan, MDc, Renu Virmani, MDb, and Jason Foerst, MDa,c,* The “Crush” procedure is a 2-stent technique for the treatment of bifurcation lesions with greater rates of in-stent restenosis than the Culotte technique. In conclusion, we report a possible mechanism for this discrepancy in the case of severe Crush stent fracture with associated focal restenosis identified by postmortem microcomputed tomography and histologic examination. Ó 2013 Published by Elsevier Inc. (Am J Cardiol 2013;111:770e773)
Figure 1. Angiographic images of coronary bifurcation stenting. (A) Initial angiogram of bifurcation lesion. (B) Stent positioning for “Crush” technique. (C) Angiogram showing “kissing” after dilation. (D) Final “Crush” angiogram.
Percutaneous treatment of coronary bifurcation lesions is technically challenging and associated with an increased risk of complications, including in-stent restenosis.1 Although a single-stent strategy is preferred, a 2-stent strategy, such as the Crush or Culotte technique,1 is
a Cardiology Section, Virginia-Tech Carilion School of Medicine and Research Institute, Roanoke, Virginia; bCVPath Institute, Gaithersburg, Maryland; cGeisel School of Medicine at Dartmouth/Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire. Manuscript received October 14, 2012; revised manuscript received and accepted November 16, 2012. See page 773 for disclosure information. *Corresponding author: Tel: (540) 982-8204; fax: (540) 224-1059. E-mail address: [email protected] (J. Foerst).
0002-9149/12/$ - see front matter Ó 2013 Published by Elsevier Inc. http://dx.doi.org/10.1016/j.amjcard.2012.11.030
frequently required. As a part of our routine autopsy protocol, we identified a Crush-treated bifurcation lesion with severe stent fracture identified in the main branch (MB) and side branch (SB) stents with associated restenosis identified on microcomputed tomography and histologic examination. Case Report A 67-year-old man with known coronary artery disease died of cardiogenic shock secondary to an anterior myocardial infarction. Three years before his death, percutaneous coronary intervention was performed to treat crescendo angina and lateral ischemia found on stress testing. Cardiac catheterization at that time revealed a Medina class www.ajconline.org
Case Report/Crush Bifurcation Restenosis
771
Figure 2. Coronary angiograms at 3 years of follow-up showing OM1 restenosis (arrows).
Figure 4. Microcomputed tomographic reconstructed images of stents. (A,B) SB ostial and SB distal reference areas.
Figure 3. Microcomputed tomographic reconstruction of coronary bifurcation stents. (A) Proximal first crown of 2.5-mm stent deployed in SB OM1 crushed against vessel wall by 3.5-mm MB left circumflex stent. (B) Flex segments between crowns 1 and 2 of SB stent are fractured, and flex segments connecting crowns 3 and 4 of MB stent are fractured.
1,1,1 left circumflex/first obtuse marginal (OM1) bifurcation lesion that was treated by deploying a 2.5 18-mm sirolimus-eluting stent (Cypher, Cordis, Bridgewater, New Jersey) in the OM1 and then a 3.5 18-mm sirolimuseluting stent in the left circumflex artery across the OM1 branch using the Crush technique (Figure 1). Coronary angiography 3 years later demonstrated subtotal occlusion of the OM1 SB (Figure 2). At autopsy, the heart was explanted and pressure fixed with 10% formalin, and the coronary arteries were perfused with bismuth/gelatin contrast. The stented arterial segment was then resected under fluoroscopic guidance and scanned with microcomputed tomography (GE LocusSP, London, Ontario, Canada) at 23-mm resolution. The data were then processed (Analyze, version 9.0, Rochester, Minnesota) to generate 2- and 3-dimensional reconstructions for examination of restenosis and stent fracture. The proximal first crown of the 2.5-mm stent deployed in the OM1 SB was crushed against the vessel wall by the 3.5-mm left circumflex MB stent (Figure 3). All the flexible N-shaped linker segments between crowns 1 and 2 of the SB stent were fractured. Adjacent to the carina, the MB stent had fracture of most of the flex segments connecting the 3 to 4, 4 to 5, and 5 to 6 crowns (Figure 3 and Video 1). The ostium of the SB was created by struts from the MB and SB stents, creating an ostial area stenosis of 37% relative to the distal SB (Figure 4). The area of greatest restenosis in the
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The American Journal of Cardiology (www.ajconline.org)
Figure 5. Three-dimensional microcomputed tomographic image (A), with representative orthogonal slice (B) demonstrating MB and SB stenosis.
Figure 6. Histologic examination of Crush-stented coronary bifurcation. (Upper Left) Postmortem radiograph to reference histologic serial cross-sections of coronary segment with stents in left circumflex/OM1 bifurcation, showing subtotal occlusion at ostium of OM1 branch. (Blue Box, Lower Left) Higher magnification image of bifurcation in which several dislocated stent struts of crown rings and linker flex segments (asterisks) are visible at the entrance of the OM1 branch, with the lumen occluded by organized thrombus. (Red Box, Lower Right) Higher magnification image of OM1 ostium, with vessel wall (media) severely injured and disrupted by stent struts.
SB and MB stents was near the region of flex segment fracture (Figure 5). Histologic examination confirmed subtotal occlusion at the ostium of the OM1 branch (Figure 6).
Discussion Approximately 10% to 15% of percutaneous coronary interventions involve bifurcation lesions.2 The results from
Case Report/Crush Bifurcation Restenosis
randomized trials have suggested that a single, provisional stent strategy is generally superior to a 2-stent strategy.3,4 However, when a 2-stent strategy is required, the Crush technique might result in greater rates of SB restenosis than the Culotte technique.5 Coronary stent fracture has been identified as a factor contributing to restenosis, and it might be an underestimated factor in Crush bifurcation stenting, especially with the older sirolimus stent platform.6,7 There are likely many factors contributing to stent fracture vulnerability, including stent design, local calcifications, vessel tortuosity and mobility, bifurcation angle, deployment protocol, and metal fatigue. We have demonstrated an association between the stent fractures of this Crush bifurcation and histologic evidence of restenosis, with local injury to the vessel media, and organized luminal thrombosis, resulting in subtotal occlusion of the SB. The present case poses a plausible mechanism for the outcome discrepancy between the Crush and Culotte techniques. To explore this hypothesis further, we identified a second case in our consecutive postmortem series in which a sirolimus stent had been implanted in the proximal left anterior descending artery 938 days before death and an everolimus stent (Promus, Boston Scientific, Natick, Massachusetts) had been implanted through a side cell into the first diagonal artery using a Culotte strategy at 520 days before death. Microcomputed tomography demonstrated a single grade I strut fracture in the sirolimus stent proximally, with no evidence of restenosis. These cases should prompt ongoing study of the prevalence and mechanisms of stent fracture in coronary bifurcation stenting. Disclosures Dr. Virmani has been a consultant for Medtronic AVE (Minneapolis, Minnesota), Abbott Vascular (Abbott Park, Illinois), Arsenal Medical (Watertown, Massachusetts), Atrium Medical Corporation (Hudson, New Hampshire), Biosensors International (Singapore), GlaxoSmithKline (Research Triangle Park, North Carolina), Lutonix (New Hope, Minnesota), and W. L. Gore (Flagstaff, Arizona); Dr. Kaplan has significant equity interest in Tryton Medical, Inc. (Durham, North Carolina), a venture-backed company developing bifurcation stents; and Dr. Kaplan has received funding from Cordis/JnJ (Bridgewater Township, New
773
Jersey), Medtronic (Minneapolis, Minnesota), Boston Scientific (Natick, Massachusetts), and Abbott Vascular (Abbott Park, Illinois). Supplementary Data Supplementary data related to this article can be found online at http://dx.doi.org/10.1016/j.amjcard.2012.11.030 1. Movahed MR. Coronary artery bifurcation lesion classifications, interventional techniques and clinical outcome. Expert Rev Cardiovasc Ther 2008;6:261e274. 2. Meier B, Gruentzig AR, King SB III, Douglas JS Jr, Hollman J, Ischinger T, Aueron F, Galan K. Risk of side branch occlusion during coronary angioplasty. Am J Cardiol 1984;53:10e14. 3. Hildick-Smith D, de Belder AJ, Cooter N, Curzen NP, Clayton TC, Oldroyd KG, Bennett L, Holmberg S, Cotton JM, Glennon PE, Thomas MR, MacCarthy PA, Baumbach A, Mulvihill NT, Henderson RA, Redwood SR, Starkey IR, Stables RH. Randomized trial of simple versus complex drug-eluting stenting for bifurcation lesions: the British Bifurcation Coronary study: old, new, and evolving strategies. Circulation 2010;121:1235e1243. 4. Steigen TK, Maeng M, Wiseth R, Erglis A, Kumsars I, Narbute I, Gunnes P, Mannsverk J, Meyerdierks O, Rotevatn S, Niemela M, Kervinen K, Jensen JS, Galloe A, Nikus K, Vikman S, Ravkilde J, James S, Aaroe J, Ylitalo A, Helqvist S, Sjogren I, Thayssen P, Virtanen K, Puhakka M, Airaksinen J, Lassen JF, Thuesen L; Nordic PCI Study Group. Randomized study on simple versus complex stenting of coronary artery bifurcation lesions: The Nordic bifurcation study. Circulation 2006;114:1955e1961. 5. Erglis A, Kumsars I, Niemela M, Kervinen K, Maeng M, Lassen JF, Gunnes P, Stavnes S, Jensen JS, Galloe A, Narbute I, Sondore D, Makikallio T, Ylitalo K, Christiansen EH, Ravkilde J, Steigen TK, Mannsverk J, Thayssen P, Hansen KN, Syvanne M, Helqvist S, Kjell N, Wiseth R, Aaroe J, Puhakka M, Thuesen L; Nordic PCI Study Group. Randomized comparison of coronary bifurcation stenting with the crush versus the Culotte technique using sirolimus eluting stents: the Nordic stent technique study. Circ Cardiovasc Interv 2009;2: 27e34. 6. Lee SE, Jeong MH, Kim IS, Ko JS, Lee MG, Kang WY, Kim SH, Sim DS, Park KH, Yoon NS, Yoon HJ, Kim KH, Hong YJ, Park HW, Kim JH, Ahn YK, Cho JG, Park JC, Kang JC. Clinical outcomes and optimal treatment for stent fracture after drug-eluting stent implantation. J Cardiol 2009;53:422e428. 7. Lemos PA, Saia F, Ligthart JM, Arampatzis CA, Sianos G, Tanabe K, Hoye A, Degertekin M, Daemen J, McFadden E, Hofma S, Smits PC, de Feyter P, van der Giessen WJ, van Domburg RT, Serruys PW. Coronary restenosis after sirolimus-eluting stent implantation: morphological description and mechanistic analysis from a consecutive series of cases. Circulation 2003;108:257e260.
Figure 1. Angiographic images of coronary bifurcation stenting. (A) Initial angiogram of bifurcation lesion. (B) Stent positioning for “Crush” technique. (C) Angiogram showing “kissing” after dilation. (D) Final “Crush” angiogram.
Percutaneous treatment of coronary bifurcation lesions is technically challenging and associated with an increased risk of complications, including in-stent restenosis.1 Although a single-stent strategy is preferred, a 2-stent strategy, such as the Crush or Culotte technique,1 is
a Cardiology Section, Virginia-Tech Carilion School of Medicine and Research Institute, Roanoke, Virginia; bCVPath Institute, Gaithersburg, Maryland; cGeisel School of Medicine at Dartmouth/Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire. Manuscript received October 14, 2012; revised manuscript received and accepted November 16, 2012. See page 773 for disclosure information. *Corresponding author: Tel: (540) 982-8204; fax: (540) 224-1059. E-mail address: [email protected] (J. Foerst).
0002-9149/12/$ - see front matter Ó 2013 Published by Elsevier Inc. http://dx.doi.org/10.1016/j.amjcard.2012.11.030
frequently required. As a part of our routine autopsy protocol, we identified a Crush-treated bifurcation lesion with severe stent fracture identified in the main branch (MB) and side branch (SB) stents with associated restenosis identified on microcomputed tomography and histologic examination. Case Report A 67-year-old man with known coronary artery disease died of cardiogenic shock secondary to an anterior myocardial infarction. Three years before his death, percutaneous coronary intervention was performed to treat crescendo angina and lateral ischemia found on stress testing. Cardiac catheterization at that time revealed a Medina class www.ajconline.org
Case Report/Crush Bifurcation Restenosis
771
Figure 2. Coronary angiograms at 3 years of follow-up showing OM1 restenosis (arrows).
Figure 4. Microcomputed tomographic reconstructed images of stents. (A,B) SB ostial and SB distal reference areas.
Figure 3. Microcomputed tomographic reconstruction of coronary bifurcation stents. (A) Proximal first crown of 2.5-mm stent deployed in SB OM1 crushed against vessel wall by 3.5-mm MB left circumflex stent. (B) Flex segments between crowns 1 and 2 of SB stent are fractured, and flex segments connecting crowns 3 and 4 of MB stent are fractured.
1,1,1 left circumflex/first obtuse marginal (OM1) bifurcation lesion that was treated by deploying a 2.5 18-mm sirolimus-eluting stent (Cypher, Cordis, Bridgewater, New Jersey) in the OM1 and then a 3.5 18-mm sirolimuseluting stent in the left circumflex artery across the OM1 branch using the Crush technique (Figure 1). Coronary angiography 3 years later demonstrated subtotal occlusion of the OM1 SB (Figure 2). At autopsy, the heart was explanted and pressure fixed with 10% formalin, and the coronary arteries were perfused with bismuth/gelatin contrast. The stented arterial segment was then resected under fluoroscopic guidance and scanned with microcomputed tomography (GE LocusSP, London, Ontario, Canada) at 23-mm resolution. The data were then processed (Analyze, version 9.0, Rochester, Minnesota) to generate 2- and 3-dimensional reconstructions for examination of restenosis and stent fracture. The proximal first crown of the 2.5-mm stent deployed in the OM1 SB was crushed against the vessel wall by the 3.5-mm left circumflex MB stent (Figure 3). All the flexible N-shaped linker segments between crowns 1 and 2 of the SB stent were fractured. Adjacent to the carina, the MB stent had fracture of most of the flex segments connecting the 3 to 4, 4 to 5, and 5 to 6 crowns (Figure 3 and Video 1). The ostium of the SB was created by struts from the MB and SB stents, creating an ostial area stenosis of 37% relative to the distal SB (Figure 4). The area of greatest restenosis in the
772
The American Journal of Cardiology (www.ajconline.org)
Figure 5. Three-dimensional microcomputed tomographic image (A), with representative orthogonal slice (B) demonstrating MB and SB stenosis.
Figure 6. Histologic examination of Crush-stented coronary bifurcation. (Upper Left) Postmortem radiograph to reference histologic serial cross-sections of coronary segment with stents in left circumflex/OM1 bifurcation, showing subtotal occlusion at ostium of OM1 branch. (Blue Box, Lower Left) Higher magnification image of bifurcation in which several dislocated stent struts of crown rings and linker flex segments (asterisks) are visible at the entrance of the OM1 branch, with the lumen occluded by organized thrombus. (Red Box, Lower Right) Higher magnification image of OM1 ostium, with vessel wall (media) severely injured and disrupted by stent struts.
SB and MB stents was near the region of flex segment fracture (Figure 5). Histologic examination confirmed subtotal occlusion at the ostium of the OM1 branch (Figure 6).
Discussion Approximately 10% to 15% of percutaneous coronary interventions involve bifurcation lesions.2 The results from
Case Report/Crush Bifurcation Restenosis
randomized trials have suggested that a single, provisional stent strategy is generally superior to a 2-stent strategy.3,4 However, when a 2-stent strategy is required, the Crush technique might result in greater rates of SB restenosis than the Culotte technique.5 Coronary stent fracture has been identified as a factor contributing to restenosis, and it might be an underestimated factor in Crush bifurcation stenting, especially with the older sirolimus stent platform.6,7 There are likely many factors contributing to stent fracture vulnerability, including stent design, local calcifications, vessel tortuosity and mobility, bifurcation angle, deployment protocol, and metal fatigue. We have demonstrated an association between the stent fractures of this Crush bifurcation and histologic evidence of restenosis, with local injury to the vessel media, and organized luminal thrombosis, resulting in subtotal occlusion of the SB. The present case poses a plausible mechanism for the outcome discrepancy between the Crush and Culotte techniques. To explore this hypothesis further, we identified a second case in our consecutive postmortem series in which a sirolimus stent had been implanted in the proximal left anterior descending artery 938 days before death and an everolimus stent (Promus, Boston Scientific, Natick, Massachusetts) had been implanted through a side cell into the first diagonal artery using a Culotte strategy at 520 days before death. Microcomputed tomography demonstrated a single grade I strut fracture in the sirolimus stent proximally, with no evidence of restenosis. These cases should prompt ongoing study of the prevalence and mechanisms of stent fracture in coronary bifurcation stenting. Disclosures Dr. Virmani has been a consultant for Medtronic AVE (Minneapolis, Minnesota), Abbott Vascular (Abbott Park, Illinois), Arsenal Medical (Watertown, Massachusetts), Atrium Medical Corporation (Hudson, New Hampshire), Biosensors International (Singapore), GlaxoSmithKline (Research Triangle Park, North Carolina), Lutonix (New Hope, Minnesota), and W. L. Gore (Flagstaff, Arizona); Dr. Kaplan has significant equity interest in Tryton Medical, Inc. (Durham, North Carolina), a venture-backed company developing bifurcation stents; and Dr. Kaplan has received funding from Cordis/JnJ (Bridgewater Township, New
773
Jersey), Medtronic (Minneapolis, Minnesota), Boston Scientific (Natick, Massachusetts), and Abbott Vascular (Abbott Park, Illinois). Supplementary Data Supplementary data related to this article can be found online at http://dx.doi.org/10.1016/j.amjcard.2012.11.030 1. Movahed MR. Coronary artery bifurcation lesion classifications, interventional techniques and clinical outcome. Expert Rev Cardiovasc Ther 2008;6:261e274. 2. Meier B, Gruentzig AR, King SB III, Douglas JS Jr, Hollman J, Ischinger T, Aueron F, Galan K. Risk of side branch occlusion during coronary angioplasty. Am J Cardiol 1984;53:10e14. 3. Hildick-Smith D, de Belder AJ, Cooter N, Curzen NP, Clayton TC, Oldroyd KG, Bennett L, Holmberg S, Cotton JM, Glennon PE, Thomas MR, MacCarthy PA, Baumbach A, Mulvihill NT, Henderson RA, Redwood SR, Starkey IR, Stables RH. Randomized trial of simple versus complex drug-eluting stenting for bifurcation lesions: the British Bifurcation Coronary study: old, new, and evolving strategies. Circulation 2010;121:1235e1243. 4. Steigen TK, Maeng M, Wiseth R, Erglis A, Kumsars I, Narbute I, Gunnes P, Mannsverk J, Meyerdierks O, Rotevatn S, Niemela M, Kervinen K, Jensen JS, Galloe A, Nikus K, Vikman S, Ravkilde J, James S, Aaroe J, Ylitalo A, Helqvist S, Sjogren I, Thayssen P, Virtanen K, Puhakka M, Airaksinen J, Lassen JF, Thuesen L; Nordic PCI Study Group. Randomized study on simple versus complex stenting of coronary artery bifurcation lesions: The Nordic bifurcation study. Circulation 2006;114:1955e1961. 5. Erglis A, Kumsars I, Niemela M, Kervinen K, Maeng M, Lassen JF, Gunnes P, Stavnes S, Jensen JS, Galloe A, Narbute I, Sondore D, Makikallio T, Ylitalo K, Christiansen EH, Ravkilde J, Steigen TK, Mannsverk J, Thayssen P, Hansen KN, Syvanne M, Helqvist S, Kjell N, Wiseth R, Aaroe J, Puhakka M, Thuesen L; Nordic PCI Study Group. Randomized comparison of coronary bifurcation stenting with the crush versus the Culotte technique using sirolimus eluting stents: the Nordic stent technique study. Circ Cardiovasc Interv 2009;2: 27e34. 6. Lee SE, Jeong MH, Kim IS, Ko JS, Lee MG, Kang WY, Kim SH, Sim DS, Park KH, Yoon NS, Yoon HJ, Kim KH, Hong YJ, Park HW, Kim JH, Ahn YK, Cho JG, Park JC, Kang JC. Clinical outcomes and optimal treatment for stent fracture after drug-eluting stent implantation. J Cardiol 2009;53:422e428. 7. Lemos PA, Saia F, Ligthart JM, Arampatzis CA, Sianos G, Tanabe K, Hoye A, Degertekin M, Daemen J, McFadden E, Hofma S, Smits PC, de Feyter P, van der Giessen WJ, van Domburg RT, Serruys PW. Coronary restenosis after sirolimus-eluting stent implantation: morphological description and mechanistic analysis from a consecutive series of cases. Circulation 2003;108:257e260.