Canadian Journal of Cardiology 31 (2015) 588e590
Editorial
Complex Percutaneous Interventions: What Is the Role for Specialized Bifurcation Stents? Mony Shuvy, MD, and Bradley H. Strauss, MD, PhD Schulich Heart Center, Sunnybrook Health Sciences Center, University of Toronto, Toronto, Ontario, Canada
See article by Gil et al., pages 671-678 of this issue. Bifurcation lesions continue to challenge the interventional cardiologist with an estimated prevalence of 15%-20% in patients who undergo percutaneous coronary intervention.1 However, the preferred technique for tackling these higherrisk lesions continues to be a debated topic.1 The goal for performing bifurcation intervention is to optimize the longterm patency of the main branch (MB), without compromising side branch (SB) patency. If not properly executed, the patient can suffer a periprocedural myocardial infarction due to loss of the SB. Even with a successful stenting result in the MB, anginal symptoms might continue if SB narrowing occurs as a result of plaque shift, even when SB patency is maintained. The first reports of performing a specialized bifurcation technique appeared in the early 1980s with the description of “kissing balloons.”2 In 1993, Colombo et al. pioneered the concept of stenting both limbs of the bifurcation, using a variety of techniques such as “V stenting” and its variant, “simultaneous kissing stents,” and “T stenting.”3 Later, even more complex 2-stent bifurcation techniques were introduced to improve SB ostial stenting and to reduce restenosis.4 The “culotte” technique uses 2 stents and leads to full coverage of the bifurcation. First, after dilation of the branches, the first stent is deployed across the more angulated branch (commonly the SB). The MB is then rewired through the struts of the stent and a second stent is positioned in the MB.5,6 The final step is a “kissing balloon” technique for optimization of the carina. In the “crush” technique, the 2 stents are positioned adjacent to each other in the proximal MB. The stent that extends into the SB is first deployed. The second stent, which extends into the MB, is then expanded, crushing the struts of the first stent that are in the proximal MB. The SB is then rewired through the MB stent, followed by kissing balloons. Received for publication January 25, 2015. Accepted January 26, 2015. Corresponding author: Dr Bradley H. Strauss, Department of Cardiovascular Sciences, Sunnybrook Health Sciences Center, 2075 Bayview Ave, D4-06, Toronto, Ontario M4N 3M5, Canada. Tel.: þ1-416-480-6066; fax: þ1-416-480-6174. E-mail: [email protected] See page 589 for disclosure information.
These bifurcation techniques are complex, time consuming, and typically result in stenting of the MB and the SB. The periprocedural and long-term outcomes were often problematic. Three major trials have assessed the various bifurcation techniques. The Coronary Bifurcations: Application of the Crushing Technique Using Sirolimus-Eluting Stents (CACTUS) trial compared elective “crush” stenting of the MB and the SB with stenting only the MB, with provisional SB stenting if necessary.7 The primary angiographic end point was in-segment restenosis rate, and the primary clinical end point was the occurrence of major adverse cardiac events (MACE; cardiac death, myocardial infarction, or target vessel revascularization [TVR]) at 6 months. The results of the study showed no significant angiographic or clinical differences between the groups. The Nordic Bifurcation Study included 413 patients; in it, MB stenting with optional stenting of the SB was compared with elective stenting of the MB and SB. There were no significant differences in MACE between the groups at 6 months. However, elective stenting of the MB and SB caused greater rates of procedure-related increases in biomarkers of myocardial injury.8 The British Bifurcation Coronary Study included 500 patients randomized to “simple” therapy (MB stenting with optional kissing balloon dilatation/or stenting the SB) or a “complex” strategy (stenting both vessels with either culotte or crush techniques, followed by mandatory kissing balloon dilatation). The primary end point (a composite at 9 months of death, myocardial infarction, and TVR) occurred in 8.0% of the simple group and 15.2% of the complex group. Most excess events in the complex group were myocardial infarctions, predominantly periprocedural. There were no significant TVR differences between the groups.9 These data have informed the interventional cardiologist to avoid SB stenting, except in special scenarios like dissection or occlusion of the SB, or in the presence of ostial involvement of a large SB. However, this approach still leaves the problem of unpredictable SB occlusion during the procedure and persistent angina because of severe residual SB stenosis. The most recent innovation to the “1-stent” technique has been the development of dedicated bifurcation stents. These stents are designed to simplify and shorten the procedure, to allow easy access to the SB, and to prevent SB occlusion and
http://dx.doi.org/10.1016/j.cjca.2015.01.026 0828-282X/Ó 2015 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.
Shuvy and Strauss Complex Percutaneous Interventions
restenosis. The first report of a dedicated stent appeared in 1999 of a left anterior descending bifurcation lesion successfully treated with the Carina Bard bifurcate stent (Bard, Galway, Ireland).10 This was followed by the Multi-Link Frontier coronary bifurcation system (Abbott Vascular, Santa Clara, CA). In 2005, a registry reported procedural success in 93% of patients. At 6 months, the MACE rate was 17.1%, mostly due to target lesion revascularization (TLR).11 In the past decade, several additional dedicated bifurcation stents have been developed and conform to 1 of 2 design concepts: (1) full SB support provided by SB stenting, followed by MB stenting (eg, Tryton Side Branch Stent [Tryton Medical, Durham, NC]); or (2) limited SB support, with stents that are positioned in the MB and facilitate access to the SB after MB stenting, without actual stenting of the SB (eg, STENTYS stent [STENTYS, Paris, France]).12-14 Both of these dedicated bifurcation stents were bare-metal stents (BMSs). The OPEN I study (STENTYS Coronary Bifurcation Stent System for the Percutaneous Treatment of de novo Lesions in Native Bifurcated Coronary Arteries), a multicentre prospective single-arm study, in which a conventional drug-eluting stent (DES) strategy was compared with the BMS STENTYS in 63 patients. The TLR rates were significantly higher with BMS STENTYS (24.2%) compared with the DES strategy (3.7%).14 In this issue of the Canadian Journal of Cardiology, the BiOSS Expert stent (Balton, Warsaw, Poland), a DES bifurcation stent that elutes paclitaxel, was compared with a conventional DES in the first randomized trial of a dedicated DES bifurcation stent and contemporary bifurcation strategy (DES with provisional stenting of the SB).15 The BiOSS Expert stent belongs to the category of dedicated bifurcation stents that improve access for SB intervention without actual stenting of the SB. The access is achieved by a design that consists of only 2 struts in the pericarinal region. In the open-label Polish Bifurcation Optimal Stenting (POLBOS I) trial, Gil et al. treated 243 patients with stable coronary artery disease and patients with non-ST-elevation myocardial infarction-acute coronary syndrome. The patients in the conventional DES arm also underwent a second randomization for final kissing balloon inflations. The BiOSS Expert stent appeared relatively easy to deliver, which has been a limitation of some previous dedicated bifurcation stents. At 12 months, overall MACEs (a composite of cardiac death, myocardial infarction, and TLR) were similar, although the rate of TLR was significantly higher in the BiOSS Expert stent group (7.3% vs 11.5%; P ¼ 0.02). Angiographic followup, achieved in 90% of the participants at the 12-month time point, showed that the rate of late lumen loss was significantly greater in the BiOSS Expert group compared with the conventional DES group: main vessel (0.35 vs 0.25 mm; P < 0.05), and MB (0.43 vs 0.30 mm; P < 0.05), but not in the SB. Final kissing balloon dilatation after stenting significantly decreased the rate of restenosis in both groups. The authors are to be congratulated on performing the first randomized trial to compare a dedicated bifurcation stent with the contemporary DES technique, and for achieving a high angiographic follow-up rate. The study teaches us many important points, including the value of the final kissing balloon to prevent restenosis. The results suggest that the BiOSS Expert bifurcation stent is safe and can be efficiently deployed. It might even be beneficial in certain bifurcation
589
lesion subgroups. A small subgroup of patients (45 patients; 19% of the group) with left main bifurcation lesions had a lower TLR rate in the BiOSS Expert group (7.4% vs 11.1%; P ¼ 0.04). This is a very preliminary observation requiring larger, prospective clinical trial data. However, the role of this particular bifurcation stent seems limited because of the higher restenosis rate. The underlying reason is not clear. A registry of 63 patients has previously shown a TVR rate of 14 %.16 The authors have speculated that the increased restenosis rate is due to paclitaxel coverage rather than use of a more effective limus-based drug. However, it is also possible that the actual BiOSS Expert design, particularly at the pericarinal region, does not provide sufficient radial strength and predisposes to higher restenosis rates. Further research with a limus-coated version of this bifurcation stent should resolve this issue. Unfortunately, interventional cardiologists who perform these complex bifurcation procedures still cannot accurately predict which bifurcation lesions will compromise the SB and cause the periprocedural complications. The role of specialized bifurcation stents, such as the BiOSS Expert, could be improved if these stents were to be selectively used in lesions with these potentially compromised SBs. This particular niche might minimize the overall requirements of specialized bifurcation stents, but allow the optimal benefit when it is actually required. In the current trial, the SB required additional balloon dilatation in more than half of the lesions in both groups, but SB stenting was only required in approximately 11% of the cases in each group. Thus, the excellent performance of a single DES strategy in most bifurcation lesions continues to challenge our ability to recognize the highrisk bifurcation lesions that would benefit from a specialized bifurcation stent. At the current juncture, we still are not able to define the exact role for a dedicated bifurcation stent. Disclosures The authors have no conflicts of interest to disclose. References 1. Waksman R, Bonello L. The 5 Ts of bifurcation intervention: type, technique, two stents, T-stenting, trials. JACC Cardiovasc Interv 2008;1: 366-8. 2. Meier B. Kissing balloon coronary angioplasty. Am J Cardiol 1984;54: 918-20. 3. Colombo A, Gaglione A, Nakamura S, Finci L. “Kissing” stents for bifurcational coronary lesion. Cathet Cardiovasc Diagn 1993;30:327-30. 4. Ge L, Iakovou I, Cosgrave J, et al. Treatment of bifurcation lesions with two stents: one year angiographic and clinical follow up of crush versus T stenting. Heart 2006;92:371-6. 5. Chevalier B, Glatt B, Royer T, Guyon P. Placement of coronary stents in bifurcation lesions by the “culotte” technique. Am J Cardiol 1998;82: 943-9. 6. Iakuvou Y, Colombo A. Two-stent techniques for the treatment of coronary bifurcations with drug-eluting stents. Hellenic J Cardiol 2005;46: 188-98. 7. Colombo A, Bramucci E, Saccà S, et al. Randomized study of the crush technique versus provisional side-branch stenting in true coronary bifurcations: the CACTUS (Coronary Bifurcations: Application of the
590
Canadian Journal of Cardiology Volume 31 2015
Crushing Technique Using Sirolimus-Eluting Stents) Study. Circulation 2009;119:71-8.
12. Pillai AA, Jayaraman B. Dedicated bifurcation stents. Indian Heart J 2012;64:187-95.
8. Steigen TK, Maeng M, Wiseth R, et al. Randomized study on simple versus complex stenting of coronary artery bifurcation lesions: the Nordic Bifurcation Study. Circulation 2006;114:1955-61.
13. Tarantini G, La Vecchia L, Galli M, et al. Clinical outcome of patients with de novo coronary bifurcation lesions treated with the Tryton side branch stent. The SAFE-TRY prospective multicenter single arm study. Int J Cardiol 2013;168:5323-8.
9. Hildick-Smith D, de Belder AJ, Cooter N, et al. Randomized trial of simple versus complex drug-eluting stenting for bifurcation lesions: the British Bifurcation Coronary study: old, new, and evolving strategies. Circulation 2010;121:1235-43.
14. Verheye S, Ramcharitar S, Grube E, et al. Six-month clinical and angiographic results of the STENTYS self-apposing stent in bifurcation lesions. EuroIntervention 2011;7:580-7.
10. Colombo A, Airoldi F, Sheiban I, Di Mario C. Successful treatment of a bifurcation lesion with the Carina Bard stent: a case report. Catheter Cardiovasc Interv 1999;48:89-92. 11. Lefèvre T, Ormiston J, Guagliumi G, et al. The FRONTIER stent registry: safety and feasibility of a novel dedicated stent for the treatment of bifurcation coronary artery lesions. J Am Coll Cardiol 2005;46:592-8.
15. Gil RJ, Bil J, Dzavík V, et al. Regular drug-eluting stent vs dedicated coronary bifurcation BiOSS expert stent: multicenter open-label randomized controlled POLBOS I Trial. Can J Cardiol 2015;31:671-8. 16. Gil R, Vassilev D, Michalek A, et al. Dedicated paclitaxel-eluting bifurcation stent BiOSS (bifurcation optimisation stent system): 12month results from a prospective registry of consecutive all-comers population. EuroIntervention 2012;8:316-24.
Editorial
Complex Percutaneous Interventions: What Is the Role for Specialized Bifurcation Stents? Mony Shuvy, MD, and Bradley H. Strauss, MD, PhD Schulich Heart Center, Sunnybrook Health Sciences Center, University of Toronto, Toronto, Ontario, Canada
See article by Gil et al., pages 671-678 of this issue. Bifurcation lesions continue to challenge the interventional cardiologist with an estimated prevalence of 15%-20% in patients who undergo percutaneous coronary intervention.1 However, the preferred technique for tackling these higherrisk lesions continues to be a debated topic.1 The goal for performing bifurcation intervention is to optimize the longterm patency of the main branch (MB), without compromising side branch (SB) patency. If not properly executed, the patient can suffer a periprocedural myocardial infarction due to loss of the SB. Even with a successful stenting result in the MB, anginal symptoms might continue if SB narrowing occurs as a result of plaque shift, even when SB patency is maintained. The first reports of performing a specialized bifurcation technique appeared in the early 1980s with the description of “kissing balloons.”2 In 1993, Colombo et al. pioneered the concept of stenting both limbs of the bifurcation, using a variety of techniques such as “V stenting” and its variant, “simultaneous kissing stents,” and “T stenting.”3 Later, even more complex 2-stent bifurcation techniques were introduced to improve SB ostial stenting and to reduce restenosis.4 The “culotte” technique uses 2 stents and leads to full coverage of the bifurcation. First, after dilation of the branches, the first stent is deployed across the more angulated branch (commonly the SB). The MB is then rewired through the struts of the stent and a second stent is positioned in the MB.5,6 The final step is a “kissing balloon” technique for optimization of the carina. In the “crush” technique, the 2 stents are positioned adjacent to each other in the proximal MB. The stent that extends into the SB is first deployed. The second stent, which extends into the MB, is then expanded, crushing the struts of the first stent that are in the proximal MB. The SB is then rewired through the MB stent, followed by kissing balloons. Received for publication January 25, 2015. Accepted January 26, 2015. Corresponding author: Dr Bradley H. Strauss, Department of Cardiovascular Sciences, Sunnybrook Health Sciences Center, 2075 Bayview Ave, D4-06, Toronto, Ontario M4N 3M5, Canada. Tel.: þ1-416-480-6066; fax: þ1-416-480-6174. E-mail: [email protected] See page 589 for disclosure information.
These bifurcation techniques are complex, time consuming, and typically result in stenting of the MB and the SB. The periprocedural and long-term outcomes were often problematic. Three major trials have assessed the various bifurcation techniques. The Coronary Bifurcations: Application of the Crushing Technique Using Sirolimus-Eluting Stents (CACTUS) trial compared elective “crush” stenting of the MB and the SB with stenting only the MB, with provisional SB stenting if necessary.7 The primary angiographic end point was in-segment restenosis rate, and the primary clinical end point was the occurrence of major adverse cardiac events (MACE; cardiac death, myocardial infarction, or target vessel revascularization [TVR]) at 6 months. The results of the study showed no significant angiographic or clinical differences between the groups. The Nordic Bifurcation Study included 413 patients; in it, MB stenting with optional stenting of the SB was compared with elective stenting of the MB and SB. There were no significant differences in MACE between the groups at 6 months. However, elective stenting of the MB and SB caused greater rates of procedure-related increases in biomarkers of myocardial injury.8 The British Bifurcation Coronary Study included 500 patients randomized to “simple” therapy (MB stenting with optional kissing balloon dilatation/or stenting the SB) or a “complex” strategy (stenting both vessels with either culotte or crush techniques, followed by mandatory kissing balloon dilatation). The primary end point (a composite at 9 months of death, myocardial infarction, and TVR) occurred in 8.0% of the simple group and 15.2% of the complex group. Most excess events in the complex group were myocardial infarctions, predominantly periprocedural. There were no significant TVR differences between the groups.9 These data have informed the interventional cardiologist to avoid SB stenting, except in special scenarios like dissection or occlusion of the SB, or in the presence of ostial involvement of a large SB. However, this approach still leaves the problem of unpredictable SB occlusion during the procedure and persistent angina because of severe residual SB stenosis. The most recent innovation to the “1-stent” technique has been the development of dedicated bifurcation stents. These stents are designed to simplify and shorten the procedure, to allow easy access to the SB, and to prevent SB occlusion and
http://dx.doi.org/10.1016/j.cjca.2015.01.026 0828-282X/Ó 2015 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.
Shuvy and Strauss Complex Percutaneous Interventions
restenosis. The first report of a dedicated stent appeared in 1999 of a left anterior descending bifurcation lesion successfully treated with the Carina Bard bifurcate stent (Bard, Galway, Ireland).10 This was followed by the Multi-Link Frontier coronary bifurcation system (Abbott Vascular, Santa Clara, CA). In 2005, a registry reported procedural success in 93% of patients. At 6 months, the MACE rate was 17.1%, mostly due to target lesion revascularization (TLR).11 In the past decade, several additional dedicated bifurcation stents have been developed and conform to 1 of 2 design concepts: (1) full SB support provided by SB stenting, followed by MB stenting (eg, Tryton Side Branch Stent [Tryton Medical, Durham, NC]); or (2) limited SB support, with stents that are positioned in the MB and facilitate access to the SB after MB stenting, without actual stenting of the SB (eg, STENTYS stent [STENTYS, Paris, France]).12-14 Both of these dedicated bifurcation stents were bare-metal stents (BMSs). The OPEN I study (STENTYS Coronary Bifurcation Stent System for the Percutaneous Treatment of de novo Lesions in Native Bifurcated Coronary Arteries), a multicentre prospective single-arm study, in which a conventional drug-eluting stent (DES) strategy was compared with the BMS STENTYS in 63 patients. The TLR rates were significantly higher with BMS STENTYS (24.2%) compared with the DES strategy (3.7%).14 In this issue of the Canadian Journal of Cardiology, the BiOSS Expert stent (Balton, Warsaw, Poland), a DES bifurcation stent that elutes paclitaxel, was compared with a conventional DES in the first randomized trial of a dedicated DES bifurcation stent and contemporary bifurcation strategy (DES with provisional stenting of the SB).15 The BiOSS Expert stent belongs to the category of dedicated bifurcation stents that improve access for SB intervention without actual stenting of the SB. The access is achieved by a design that consists of only 2 struts in the pericarinal region. In the open-label Polish Bifurcation Optimal Stenting (POLBOS I) trial, Gil et al. treated 243 patients with stable coronary artery disease and patients with non-ST-elevation myocardial infarction-acute coronary syndrome. The patients in the conventional DES arm also underwent a second randomization for final kissing balloon inflations. The BiOSS Expert stent appeared relatively easy to deliver, which has been a limitation of some previous dedicated bifurcation stents. At 12 months, overall MACEs (a composite of cardiac death, myocardial infarction, and TLR) were similar, although the rate of TLR was significantly higher in the BiOSS Expert stent group (7.3% vs 11.5%; P ¼ 0.02). Angiographic followup, achieved in 90% of the participants at the 12-month time point, showed that the rate of late lumen loss was significantly greater in the BiOSS Expert group compared with the conventional DES group: main vessel (0.35 vs 0.25 mm; P < 0.05), and MB (0.43 vs 0.30 mm; P < 0.05), but not in the SB. Final kissing balloon dilatation after stenting significantly decreased the rate of restenosis in both groups. The authors are to be congratulated on performing the first randomized trial to compare a dedicated bifurcation stent with the contemporary DES technique, and for achieving a high angiographic follow-up rate. The study teaches us many important points, including the value of the final kissing balloon to prevent restenosis. The results suggest that the BiOSS Expert bifurcation stent is safe and can be efficiently deployed. It might even be beneficial in certain bifurcation
589
lesion subgroups. A small subgroup of patients (45 patients; 19% of the group) with left main bifurcation lesions had a lower TLR rate in the BiOSS Expert group (7.4% vs 11.1%; P ¼ 0.04). This is a very preliminary observation requiring larger, prospective clinical trial data. However, the role of this particular bifurcation stent seems limited because of the higher restenosis rate. The underlying reason is not clear. A registry of 63 patients has previously shown a TVR rate of 14 %.16 The authors have speculated that the increased restenosis rate is due to paclitaxel coverage rather than use of a more effective limus-based drug. However, it is also possible that the actual BiOSS Expert design, particularly at the pericarinal region, does not provide sufficient radial strength and predisposes to higher restenosis rates. Further research with a limus-coated version of this bifurcation stent should resolve this issue. Unfortunately, interventional cardiologists who perform these complex bifurcation procedures still cannot accurately predict which bifurcation lesions will compromise the SB and cause the periprocedural complications. The role of specialized bifurcation stents, such as the BiOSS Expert, could be improved if these stents were to be selectively used in lesions with these potentially compromised SBs. This particular niche might minimize the overall requirements of specialized bifurcation stents, but allow the optimal benefit when it is actually required. In the current trial, the SB required additional balloon dilatation in more than half of the lesions in both groups, but SB stenting was only required in approximately 11% of the cases in each group. Thus, the excellent performance of a single DES strategy in most bifurcation lesions continues to challenge our ability to recognize the highrisk bifurcation lesions that would benefit from a specialized bifurcation stent. At the current juncture, we still are not able to define the exact role for a dedicated bifurcation stent. Disclosures The authors have no conflicts of interest to disclose. References 1. Waksman R, Bonello L. The 5 Ts of bifurcation intervention: type, technique, two stents, T-stenting, trials. JACC Cardiovasc Interv 2008;1: 366-8. 2. Meier B. Kissing balloon coronary angioplasty. Am J Cardiol 1984;54: 918-20. 3. Colombo A, Gaglione A, Nakamura S, Finci L. “Kissing” stents for bifurcational coronary lesion. Cathet Cardiovasc Diagn 1993;30:327-30. 4. Ge L, Iakovou I, Cosgrave J, et al. Treatment of bifurcation lesions with two stents: one year angiographic and clinical follow up of crush versus T stenting. Heart 2006;92:371-6. 5. Chevalier B, Glatt B, Royer T, Guyon P. Placement of coronary stents in bifurcation lesions by the “culotte” technique. Am J Cardiol 1998;82: 943-9. 6. Iakuvou Y, Colombo A. Two-stent techniques for the treatment of coronary bifurcations with drug-eluting stents. Hellenic J Cardiol 2005;46: 188-98. 7. Colombo A, Bramucci E, Saccà S, et al. Randomized study of the crush technique versus provisional side-branch stenting in true coronary bifurcations: the CACTUS (Coronary Bifurcations: Application of the
590
Canadian Journal of Cardiology Volume 31 2015
Crushing Technique Using Sirolimus-Eluting Stents) Study. Circulation 2009;119:71-8.
12. Pillai AA, Jayaraman B. Dedicated bifurcation stents. Indian Heart J 2012;64:187-95.
8. Steigen TK, Maeng M, Wiseth R, et al. Randomized study on simple versus complex stenting of coronary artery bifurcation lesions: the Nordic Bifurcation Study. Circulation 2006;114:1955-61.
13. Tarantini G, La Vecchia L, Galli M, et al. Clinical outcome of patients with de novo coronary bifurcation lesions treated with the Tryton side branch stent. The SAFE-TRY prospective multicenter single arm study. Int J Cardiol 2013;168:5323-8.
9. Hildick-Smith D, de Belder AJ, Cooter N, et al. Randomized trial of simple versus complex drug-eluting stenting for bifurcation lesions: the British Bifurcation Coronary study: old, new, and evolving strategies. Circulation 2010;121:1235-43.
14. Verheye S, Ramcharitar S, Grube E, et al. Six-month clinical and angiographic results of the STENTYS self-apposing stent in bifurcation lesions. EuroIntervention 2011;7:580-7.
10. Colombo A, Airoldi F, Sheiban I, Di Mario C. Successful treatment of a bifurcation lesion with the Carina Bard stent: a case report. Catheter Cardiovasc Interv 1999;48:89-92. 11. Lefèvre T, Ormiston J, Guagliumi G, et al. The FRONTIER stent registry: safety and feasibility of a novel dedicated stent for the treatment of bifurcation coronary artery lesions. J Am Coll Cardiol 2005;46:592-8.
15. Gil RJ, Bil J, Dzavík V, et al. Regular drug-eluting stent vs dedicated coronary bifurcation BiOSS expert stent: multicenter open-label randomized controlled POLBOS I Trial. Can J Cardiol 2015;31:671-8. 16. Gil R, Vassilev D, Michalek A, et al. Dedicated paclitaxel-eluting bifurcation stent BiOSS (bifurcation optimisation stent system): 12month results from a prospective registry of consecutive all-comers population. EuroIntervention 2012;8:316-24.
