Canadian Journal of Cardiology 31 (2015) 247e249
Editorial
Bioresorbable Vascular Scaffolds: A New Revolution in Percutaneous Coronary Intervention? Vinoda Sharma, MD, MRCP, and Vladimír Dzavík, MD, FRCPC Peter Munk Cardiac Centre, University Health Network, Toronto, Ontario, Canada
See article by Sato et al., pages 328-334 of this issue. The introduction of the drug-eluting stent to percutaneous coronary intervention had a great effect on patient management and has been called the “third revolution” in interventional cardiology after the first 2 revolutions of balloon angioplasty and bare-metal stents.1 A drug-eluting stent consists of an antiproliferative drug, a stent polymer (drug carrier vehicle), and a metallic stent platform or scaffold. When the drug is absorbed, the stent polymer becomes nonfunctional but has been implicated in a hypersensitivity reaction that can trigger neoatherosclerosis and stent thrombosis. This can occur many years after the procedure, especially in the case of first-generation drug-eluting stents.2 Stent thrombosis is less frequent with second-generation drug-eluting stents that have cobalt chromium or platinum chromium platforms and newer, more biocompatible polymers.3 Drug-eluting stents can also cause paradoxical vasoconstriction at the distal stent edge, loss of vasomotion, and endothelial dysfunction.4 Despite these limitations, the use of drug-eluting stents has evolved to include complex 2-stent bifurcation procedures and full metal jackets for the treatment of long diffuse lesions including chronic total occlusions. A stent with a completely resorbable polymer and scaffold that would aid in the restoration of vasomotion and endothelial function would likely circumvent these disadvantages. The ABSORB (Abbott Vascular, Santa Clara, CA) bioresorbable vascular scaffold (BVS) is the first such device to have undergone clinical study and to now be available for clinical use worldwide. However, in Canada it is currently available only with Special Access authorization from Health Canada. The device consists of a polymer (poly-L lactide) backbone coated with an amorphous drug matrix consisting of a mixture of a second polymer (poly-D, L lactide) and the antiproliferative drug, everolimus. Both of the polymers undergo degradation and are completely bioresorbed within 24 Received for publication January 19, 2015. Accepted January 25, 2015. Corresponding author: Dr Vladimír Dzavík, Interventional Cardiology Program, Peter Munk Cardiac Centre, 6-246 EN, Toronto General Hospital, 200 Elizabeth Street, Toronto, Ontario M5G 2C4, Canada. Tel.: þ1-416340-4800 6265; fax: þ1-416-340-3390. E-mail: [email protected] See page 248 for disclosure information.
months. The resultant soluble lactate monomers enter the Krebs cycle and are eliminated by the lungs and kidneys, being converted to water and carbon dioxide.1 The absence of any residual polymer should potentially reduce the risk of very late scaffold thrombosis.1 Early studies that tested the BVS on simple coronary anatomy reported no scaffold thrombosis out to 5 years.5 BVS implantation has been shown to facilitate the return of vasomotion and endothelial function. Restoration of vasomotion, observed as early as 1 year after implantation,6 might be responsible for the post hoc observation of reduced cumulative angina rates with BVS at 1 year compared with the Xience (Abbott Vascular) metallic everolimus-eluting stent in the ABSORB II trial.7 Other potential benefits of BVS are also attributable to the complete resorption of the scaffold. Complex bifurcation stenting with BVS avoids “permanent jailing” of side branches. The lack of a metallic cage in long treated lengths of coronary arteries allows for future surgical revascularization. Finally, the “blooming artifact” observed with metal stents on computed tomography and magnetic resonance imaging is not observed with BVS, facilitating the use of these imaging modalities in follow-up.1 The feasibility of using the ABSORB BVS in complex coronary anatomy has been suggested in case reports, bench testing, and registry data.8-11 Some of these studies have highlighted the potential for problems if precautions were not taken during BVS deployment.9 Thus, potential benefits might be limited by potential drawbacks, the main one being the propensity of the ABSORB BVS to fracture when dilated beyond a fairly narrow stretch tolerance.9,12 Aggressive postdilation or kissing balloon inflation of BVS implants in bifurcation lesions, for example, can result in unravelling or fracture of the struts.9 Furthermore, with the exception of platinum markers at either end, the BVS is completely radiolucent and simply cannot be visualized angiographically. Hence, especially in the case of more complex procedures, such as those involving bifurcations or overlapping stents, the only way to ensure adequate strut apposition or absence of strut fracture, is by intravascular imaging.13,14 This adds cost, time, and in the case of optical coherence tomography, the preferred imaging modality for visualization of BVS,15 volume of contrast, a potential problem for patients with
http://dx.doi.org/10.1016/j.cjca.2015.01.020 0828-282X/Ó 2015 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.
248
compromised renal or cardiac function. Finally, unlike in the early studies, real-world data from recent registries such as the Gauging coronary Healing With Bioresorbable Scaffolding Platforms in Europe (GHOST-EU) European multicentre registry show that scaffold thrombosis does occur, at a not negligible rate of 2.1% at 6 months.8 In this issue of the Canadian Journal of Cardiology, Sato et al. report on the procedural and long-term outcomes of an all-comer cohort of 96 patients treated with the ABSORB BVS compared with a propensity-matched group of 96 patients treated with second-generation drug-eluting stents.14 It is the first study to report on outcomes after BVS deployment in patients with mainly complex lesions (> 80% of lesions), and also the first to provide a comparison, not randomized, but at least with a propensity-matched group treated with standard metallic drug-eluting stents. More than a third were bifurcation lesions and a quarter of the lesions were calcified. The authors chose procedural time, fluoroscopy time, and contrast volume as their primary end points. In all 3 parameters, the BVS device was associated with less favourable results; procedural and fluoroscopy times were longer, and contrast volume used was greater. This is as much likely a factor of the bulky nature of the BVS that is known to be more difficult to deliver, especially in calcified, tortuous anatomy, as it is of the meticulous preparation that was therefore required to achieve the excellent results that were achieved.14 Intravascular imaging was used in almost all of the BVS cases compared with the drug-eluting stent cases (used only in two-thirds). This again reflects the reality that the ABSORB BVS cannot be visualized angiographically and intravascular imaging is required in complex procedures to ensure integrity of the deployed device. With all of this, the authors found no difference in acute angiographic outcomes or 1-year clinical outcomes between the 2 groups. The estimated 1-year stent thrombosis rates were 1% for the BVS vs 2.1% for drug-eluting stents, similar to the rates reported in a pooled outcome comparison of the ABSORB and SPIRIT trials, which showed a stent thrombosis rate of 1% for the BVS and 1.7% for everolimus-eluting stents.16 Keeping in mind the small sample size, the lower rate of scaffold thrombosis of 1% for BVS14 compared with the rate of 2.1% at 6 months in GHOST-EU,8 might again be a reflection of the meticulous preparation of the lesions and the almost universal use of intravascular imaging to guide deployment. So, is this new technology, so far without much more than a promissory note of a better quality of life and better patient outcomes, really worth all the trouble? The pursuit of a future without a permanent metal cage in the coronary vessel wall for our patients who undergo percutaneous coronary intervention is certainly worthwhile. Sato et al. have given us the first comparative glimpse that suggests that this could become a reality for most patients with quite complex disease.14 Nonetheless, it is far too early to give the BVS a green light as a workhorse tool. Randomized trials are needed in more complex patient populations than have been studied to date, to confirm what the observations from the Centro Cuore Columbus are suggesting is possible. Any first-generation device will have its imperfections. With its propensity to fracture when dilated beyond a relatively narrow diameter range, and its relatively thick struts, the ABSORB BVS certainly has them. A second poly-L lactide
Canadian Journal of Cardiology Volume 31 2015
scaffold, the DESolve (Elixir Medical, Sunnyvale, CA), with a much wider safety margin for expansion (the 3.0-mm diameter DESolve scaffold can be dilated to 4.5 mm) has shown promising results at 2-year follow-up.17,18 A thinner and more flexible version of ABSORB with strut thickness < 100 mm and with more favourable “stretch” characteristics is also under development (Dr Richard Rapoza, personal communication), as are other devices, made of other materials.1 Until results of clinical trials with these devices are available, Sato et al.14 have shown us what is possible and that we must continue to strive with this “fourth revolution”1 in percutaneous coronary intervention. Disclosures Dr Dzavík has in the past received unrestricted research grant support and speaker honoraria from Abbott Vascular. Dr Sharma has no conflicts of interest to disclose. References 1. Onuma Y, Serruys PW. Bioresorbable scaffold: the advent of a new era in percutaneous coronary and peripheral revascularization? Circulation 2011;123:779-97. 2. Virmani R, Guagliumi G, Farb A, et al. Localized hypersensitivity and late coronary thrombosis secondary to a sirolimus-eluting stent: should we be cautious? Circulation 2004;109:701-5. 3. Palmerini T, Biondi-Zoccai G, Della Riva D, et al. Stent thrombosis with drug-eluting and bare-metal stents: evidence from a comprehensive network meta-analysis. Lancet 2012;379:1393-402. 4. Hofma SH, van der Giessen WJ, van Dalen BM, et al. Indication of longterm endothelial dysfunction after sirolimus-eluting stent implantation. Eur Heart J 2006;27:166-70. 5. Onuma Y, Dudek D, Thuesen L, et al. Five-year clinical and functional multislice computed tomography angiographic results after coronary implantation of the fully resorbable polymeric everolimus-eluting scaffold in patients with de novo coronary artery disease: the ABSORB cohort A trial. JACC Cardiovasc Interv 2013;6:999-1009. 6. Brugaletta S, Heo JH, Garcia-Garcia HM, et al. Endothelial-dependent vasomotion in a coronary segment treated by ABSORB everolimuseluting bioresorbable vascular scaffold system is related to plaque composition at the time of bioresorption of the polymer: indirect finding of vascular reparative therapy? Eur Heart J 2012;33:1325-33. 7. Serruys PW, Chevalier B, Dudek D, et al. A bioresorbable everolimuseluting scaffold versus a metallic everolimus-eluting stent for ischaemic heart disease caused by de-novo native coronary artery lesions (ABSORB II): an interim 1-year analysis of clinical and procedural secondary outcomes from a randomised controlled trial. Lancet 2015;385:43-54. 8. Capodanno D, Gori T, Nef H, et al. Percutaneous coronary intervention with everolimus-eluting bioresorbable vascular scaffolds in routine clinical practice: early and midterm outcomes from the European multicentre GHOST-EU registry. EuroIntervention 2015;10:1144-53. 9. Dzavik V, Colombo A. The absorb bioresorbable vascular scaffold in coronary bifurcations: insights from bench testing. JACC Cardiovasc Interv 2014;7:81-8. 10. Dzavik V, Muramatsu T, Crooks N, Nakatani S, Onuma Y. Complex bifurcation percutaneous coronary intervention with the Absorb bioresorbable vascular scaffold. EuroIntervention 2013;9:888.
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11. Liang M, Kajiya T, Lee CH, et al. Initial experience in the clinical use of everolimus-eluting bioresorbable vascular scaffold (BVS) in a single institution. Int J Cardiol 2013;168:1536-7.
tomography for the analysis of the bioresorbable vascular scaffold. Catheter Cardiovasc Interv 2012;79:890-902.
12. Ormiston JA, Webber B, Ubod B, Webster MW, White J. Absorb everolimus-eluting bioresorbable scaffolds in coronary bifurcations: a bench study of deployment, side branch dilatation and post-dilatation strategies. EuroIntervention 2015;10:1169-77.
16. Muramatsu T, Onuma Y, van Geuns RJ, et al. 1-year clinical outcomes of diabetic patients treated with everolimus-eluting bioresorbable vascular scaffolds: a pooled analysis of the ABSORB and the SPIRIT trials. JACC Cardiovasc Interv 2014;7:482-93.
13. Ishibashi Y, Onuma Y, Muramatsu T, et al. Lessons learned from acute and late scaffold failures in the ABSORB EXTEND trial. EuroIntervention 2014;10:449-57. 14. Sato K, Latib A, Panoulas VF, et al. Procedural feasibility and clinical outcomes in propensity-matched patients treated with bioresorbable scaffolds vs new-generation drug-eluting stents. Can J Cardiol 2015;31:328-34. 15. Gomez-Lara J, Brugaletta S, Diletti R, et al. Agreement and reproducibility of gray-scale intravascular ultrasound and optical coherence
17. Abizaid A, Schofer J, Maeng M, et al. TCT-610. Prospective, multicenter evaluation of the DESolve novolimus-eluting bioresorbable coronary scaffold: imaging outcomes and 2-year clinical results [abstract TCT-610]. J Am Coll Cardiol 2014;64(suppl B):B178. 18. Verheye S, Ormiston JA, Stewart J, et al. A next-generation bioresorbable coronary scaffold system: from bench to first clinical evaluation: 6- and 12-month clinical and multimodality imaging results. JACC Cardiovasc Interv 2014;7:89-99.
Editorial
Bioresorbable Vascular Scaffolds: A New Revolution in Percutaneous Coronary Intervention? Vinoda Sharma, MD, MRCP, and Vladimír Dzavík, MD, FRCPC Peter Munk Cardiac Centre, University Health Network, Toronto, Ontario, Canada
See article by Sato et al., pages 328-334 of this issue. The introduction of the drug-eluting stent to percutaneous coronary intervention had a great effect on patient management and has been called the “third revolution” in interventional cardiology after the first 2 revolutions of balloon angioplasty and bare-metal stents.1 A drug-eluting stent consists of an antiproliferative drug, a stent polymer (drug carrier vehicle), and a metallic stent platform or scaffold. When the drug is absorbed, the stent polymer becomes nonfunctional but has been implicated in a hypersensitivity reaction that can trigger neoatherosclerosis and stent thrombosis. This can occur many years after the procedure, especially in the case of first-generation drug-eluting stents.2 Stent thrombosis is less frequent with second-generation drug-eluting stents that have cobalt chromium or platinum chromium platforms and newer, more biocompatible polymers.3 Drug-eluting stents can also cause paradoxical vasoconstriction at the distal stent edge, loss of vasomotion, and endothelial dysfunction.4 Despite these limitations, the use of drug-eluting stents has evolved to include complex 2-stent bifurcation procedures and full metal jackets for the treatment of long diffuse lesions including chronic total occlusions. A stent with a completely resorbable polymer and scaffold that would aid in the restoration of vasomotion and endothelial function would likely circumvent these disadvantages. The ABSORB (Abbott Vascular, Santa Clara, CA) bioresorbable vascular scaffold (BVS) is the first such device to have undergone clinical study and to now be available for clinical use worldwide. However, in Canada it is currently available only with Special Access authorization from Health Canada. The device consists of a polymer (poly-L lactide) backbone coated with an amorphous drug matrix consisting of a mixture of a second polymer (poly-D, L lactide) and the antiproliferative drug, everolimus. Both of the polymers undergo degradation and are completely bioresorbed within 24 Received for publication January 19, 2015. Accepted January 25, 2015. Corresponding author: Dr Vladimír Dzavík, Interventional Cardiology Program, Peter Munk Cardiac Centre, 6-246 EN, Toronto General Hospital, 200 Elizabeth Street, Toronto, Ontario M5G 2C4, Canada. Tel.: þ1-416340-4800 6265; fax: þ1-416-340-3390. E-mail: [email protected] See page 248 for disclosure information.
months. The resultant soluble lactate monomers enter the Krebs cycle and are eliminated by the lungs and kidneys, being converted to water and carbon dioxide.1 The absence of any residual polymer should potentially reduce the risk of very late scaffold thrombosis.1 Early studies that tested the BVS on simple coronary anatomy reported no scaffold thrombosis out to 5 years.5 BVS implantation has been shown to facilitate the return of vasomotion and endothelial function. Restoration of vasomotion, observed as early as 1 year after implantation,6 might be responsible for the post hoc observation of reduced cumulative angina rates with BVS at 1 year compared with the Xience (Abbott Vascular) metallic everolimus-eluting stent in the ABSORB II trial.7 Other potential benefits of BVS are also attributable to the complete resorption of the scaffold. Complex bifurcation stenting with BVS avoids “permanent jailing” of side branches. The lack of a metallic cage in long treated lengths of coronary arteries allows for future surgical revascularization. Finally, the “blooming artifact” observed with metal stents on computed tomography and magnetic resonance imaging is not observed with BVS, facilitating the use of these imaging modalities in follow-up.1 The feasibility of using the ABSORB BVS in complex coronary anatomy has been suggested in case reports, bench testing, and registry data.8-11 Some of these studies have highlighted the potential for problems if precautions were not taken during BVS deployment.9 Thus, potential benefits might be limited by potential drawbacks, the main one being the propensity of the ABSORB BVS to fracture when dilated beyond a fairly narrow stretch tolerance.9,12 Aggressive postdilation or kissing balloon inflation of BVS implants in bifurcation lesions, for example, can result in unravelling or fracture of the struts.9 Furthermore, with the exception of platinum markers at either end, the BVS is completely radiolucent and simply cannot be visualized angiographically. Hence, especially in the case of more complex procedures, such as those involving bifurcations or overlapping stents, the only way to ensure adequate strut apposition or absence of strut fracture, is by intravascular imaging.13,14 This adds cost, time, and in the case of optical coherence tomography, the preferred imaging modality for visualization of BVS,15 volume of contrast, a potential problem for patients with
http://dx.doi.org/10.1016/j.cjca.2015.01.020 0828-282X/Ó 2015 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.
248
compromised renal or cardiac function. Finally, unlike in the early studies, real-world data from recent registries such as the Gauging coronary Healing With Bioresorbable Scaffolding Platforms in Europe (GHOST-EU) European multicentre registry show that scaffold thrombosis does occur, at a not negligible rate of 2.1% at 6 months.8 In this issue of the Canadian Journal of Cardiology, Sato et al. report on the procedural and long-term outcomes of an all-comer cohort of 96 patients treated with the ABSORB BVS compared with a propensity-matched group of 96 patients treated with second-generation drug-eluting stents.14 It is the first study to report on outcomes after BVS deployment in patients with mainly complex lesions (> 80% of lesions), and also the first to provide a comparison, not randomized, but at least with a propensity-matched group treated with standard metallic drug-eluting stents. More than a third were bifurcation lesions and a quarter of the lesions were calcified. The authors chose procedural time, fluoroscopy time, and contrast volume as their primary end points. In all 3 parameters, the BVS device was associated with less favourable results; procedural and fluoroscopy times were longer, and contrast volume used was greater. This is as much likely a factor of the bulky nature of the BVS that is known to be more difficult to deliver, especially in calcified, tortuous anatomy, as it is of the meticulous preparation that was therefore required to achieve the excellent results that were achieved.14 Intravascular imaging was used in almost all of the BVS cases compared with the drug-eluting stent cases (used only in two-thirds). This again reflects the reality that the ABSORB BVS cannot be visualized angiographically and intravascular imaging is required in complex procedures to ensure integrity of the deployed device. With all of this, the authors found no difference in acute angiographic outcomes or 1-year clinical outcomes between the 2 groups. The estimated 1-year stent thrombosis rates were 1% for the BVS vs 2.1% for drug-eluting stents, similar to the rates reported in a pooled outcome comparison of the ABSORB and SPIRIT trials, which showed a stent thrombosis rate of 1% for the BVS and 1.7% for everolimus-eluting stents.16 Keeping in mind the small sample size, the lower rate of scaffold thrombosis of 1% for BVS14 compared with the rate of 2.1% at 6 months in GHOST-EU,8 might again be a reflection of the meticulous preparation of the lesions and the almost universal use of intravascular imaging to guide deployment. So, is this new technology, so far without much more than a promissory note of a better quality of life and better patient outcomes, really worth all the trouble? The pursuit of a future without a permanent metal cage in the coronary vessel wall for our patients who undergo percutaneous coronary intervention is certainly worthwhile. Sato et al. have given us the first comparative glimpse that suggests that this could become a reality for most patients with quite complex disease.14 Nonetheless, it is far too early to give the BVS a green light as a workhorse tool. Randomized trials are needed in more complex patient populations than have been studied to date, to confirm what the observations from the Centro Cuore Columbus are suggesting is possible. Any first-generation device will have its imperfections. With its propensity to fracture when dilated beyond a relatively narrow diameter range, and its relatively thick struts, the ABSORB BVS certainly has them. A second poly-L lactide
Canadian Journal of Cardiology Volume 31 2015
scaffold, the DESolve (Elixir Medical, Sunnyvale, CA), with a much wider safety margin for expansion (the 3.0-mm diameter DESolve scaffold can be dilated to 4.5 mm) has shown promising results at 2-year follow-up.17,18 A thinner and more flexible version of ABSORB with strut thickness < 100 mm and with more favourable “stretch” characteristics is also under development (Dr Richard Rapoza, personal communication), as are other devices, made of other materials.1 Until results of clinical trials with these devices are available, Sato et al.14 have shown us what is possible and that we must continue to strive with this “fourth revolution”1 in percutaneous coronary intervention. Disclosures Dr Dzavík has in the past received unrestricted research grant support and speaker honoraria from Abbott Vascular. Dr Sharma has no conflicts of interest to disclose. References 1. Onuma Y, Serruys PW. Bioresorbable scaffold: the advent of a new era in percutaneous coronary and peripheral revascularization? Circulation 2011;123:779-97. 2. Virmani R, Guagliumi G, Farb A, et al. Localized hypersensitivity and late coronary thrombosis secondary to a sirolimus-eluting stent: should we be cautious? Circulation 2004;109:701-5. 3. Palmerini T, Biondi-Zoccai G, Della Riva D, et al. Stent thrombosis with drug-eluting and bare-metal stents: evidence from a comprehensive network meta-analysis. Lancet 2012;379:1393-402. 4. Hofma SH, van der Giessen WJ, van Dalen BM, et al. Indication of longterm endothelial dysfunction after sirolimus-eluting stent implantation. Eur Heart J 2006;27:166-70. 5. Onuma Y, Dudek D, Thuesen L, et al. Five-year clinical and functional multislice computed tomography angiographic results after coronary implantation of the fully resorbable polymeric everolimus-eluting scaffold in patients with de novo coronary artery disease: the ABSORB cohort A trial. JACC Cardiovasc Interv 2013;6:999-1009. 6. Brugaletta S, Heo JH, Garcia-Garcia HM, et al. Endothelial-dependent vasomotion in a coronary segment treated by ABSORB everolimuseluting bioresorbable vascular scaffold system is related to plaque composition at the time of bioresorption of the polymer: indirect finding of vascular reparative therapy? Eur Heart J 2012;33:1325-33. 7. Serruys PW, Chevalier B, Dudek D, et al. A bioresorbable everolimuseluting scaffold versus a metallic everolimus-eluting stent for ischaemic heart disease caused by de-novo native coronary artery lesions (ABSORB II): an interim 1-year analysis of clinical and procedural secondary outcomes from a randomised controlled trial. Lancet 2015;385:43-54. 8. Capodanno D, Gori T, Nef H, et al. Percutaneous coronary intervention with everolimus-eluting bioresorbable vascular scaffolds in routine clinical practice: early and midterm outcomes from the European multicentre GHOST-EU registry. EuroIntervention 2015;10:1144-53. 9. Dzavik V, Colombo A. The absorb bioresorbable vascular scaffold in coronary bifurcations: insights from bench testing. JACC Cardiovasc Interv 2014;7:81-8. 10. Dzavik V, Muramatsu T, Crooks N, Nakatani S, Onuma Y. Complex bifurcation percutaneous coronary intervention with the Absorb bioresorbable vascular scaffold. EuroIntervention 2013;9:888.
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11. Liang M, Kajiya T, Lee CH, et al. Initial experience in the clinical use of everolimus-eluting bioresorbable vascular scaffold (BVS) in a single institution. Int J Cardiol 2013;168:1536-7.
tomography for the analysis of the bioresorbable vascular scaffold. Catheter Cardiovasc Interv 2012;79:890-902.
12. Ormiston JA, Webber B, Ubod B, Webster MW, White J. Absorb everolimus-eluting bioresorbable scaffolds in coronary bifurcations: a bench study of deployment, side branch dilatation and post-dilatation strategies. EuroIntervention 2015;10:1169-77.
16. Muramatsu T, Onuma Y, van Geuns RJ, et al. 1-year clinical outcomes of diabetic patients treated with everolimus-eluting bioresorbable vascular scaffolds: a pooled analysis of the ABSORB and the SPIRIT trials. JACC Cardiovasc Interv 2014;7:482-93.
13. Ishibashi Y, Onuma Y, Muramatsu T, et al. Lessons learned from acute and late scaffold failures in the ABSORB EXTEND trial. EuroIntervention 2014;10:449-57. 14. Sato K, Latib A, Panoulas VF, et al. Procedural feasibility and clinical outcomes in propensity-matched patients treated with bioresorbable scaffolds vs new-generation drug-eluting stents. Can J Cardiol 2015;31:328-34. 15. Gomez-Lara J, Brugaletta S, Diletti R, et al. Agreement and reproducibility of gray-scale intravascular ultrasound and optical coherence
17. Abizaid A, Schofer J, Maeng M, et al. TCT-610. Prospective, multicenter evaluation of the DESolve novolimus-eluting bioresorbable coronary scaffold: imaging outcomes and 2-year clinical results [abstract TCT-610]. J Am Coll Cardiol 2014;64(suppl B):B178. 18. Verheye S, Ormiston JA, Stewart J, et al. A next-generation bioresorbable coronary scaffold system: from bench to first clinical evaluation: 6- and 12-month clinical and multimodality imaging results. JACC Cardiovasc Interv 2014;7:89-99.
