Expert Review of Cardiovascular Therapy

ISSN: 1477-9072 (Print) 1744-8344 (Online) Journal homepage: http://www.tandfonline.com/loi/ierk20

Percutaneous treatment of left main and nonleft main bifurcation coronary lesions using drugeluting stents Jae-Hyung Roh & Young-Hak Kim To cite this article: Jae-Hyung Roh & Young-Hak Kim (2016) Percutaneous treatment of left main and non-left main bifurcation coronary lesions using drug-eluting stents, Expert Review of Cardiovascular Therapy, 14:2, 229-243, DOI: 10.1586/14779072.2016.1120158 To link to this article: http://dx.doi.org/10.1586/14779072.2016.1120158

Accepted author version posted online: 12 Nov 2015. Published online: 29 Dec 2015. Submit your article to this journal

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Date: 17 February 2016, At: 05:52

EXPERT REVIEW OF CARDIOVASCULAR THERAPY, 2016 VOL. 14, NO. 2, 229–243 http://dx.doi.org/10.1586/14779072.2016.1120158

REVIEW

Percutaneous treatment of left main and non-left main bifurcation coronary lesions using drug-eluting stents Jae-Hyung Roh and Young-Hak Kim

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Asan Medical Center - Cardiology Division, University of Ulsan College of Medicine, Seoul, Korea ABSTRACT

ARTICLE HISTORY

Current evidence and guidelines support the use of the single-stent technique as the default treatment strategy for the treatment of coronary bifurcations. For the single-stent technique, routine final kissing balloon inflation is not recommended, unless side branch ostial stenosis is assumed to be functionally significant. The double-stent technique is still a viable option for bifurcations with large and severely diseased side branches. Due to the unique features of bifurcation anatomy and bifurcation stenting techniques, all deployed stents should be optimized by postdilation, kissing balloon inflation and/or the proximal optimization technique, regardless of the stenting technique used. Intravascular ultrasound can guide preimplantation decisionmaking and postimplantation optimization by providing information on reference diameter, plaque burden and distribution, and stent underexpansion and malapposition.

Received 26 September 2015 Accepted 11 November 2015

Introduction A coronary bifurcation lesion is defined as a lesion located at, or adjacent to, a significant division of a major epicardial coronary artery.[1] The significance of side branch (SB) is, albeit arbitrarily, commonly defined based on the amount of viable myocardium supplied by it. Coronary bifurcations are encountered in between 15 and 20% of all percutaneous coronary interventions (PCIs) and are thus relatively common.[2] However, because of their uniformly cylindrical shape, coronary stents have limitations in treating a variety of bifurcation lesions heterogeneous in characteristics, such as the bifurcation angle, SB size, stenosis severity and plaque distribution, resulting in a difficult procedure and poor long-term outcomes. To overcome the limitations of coronary stents, many bifurcation stenting techniques have been introduced, although none have been proven to be superior to the others in randomized trials. Likewise, the recently published Choice of Optimal Strategy for Bifurcation Lesions With Normal Side Branch (CROSS) and Optimal Stenting Strategy for True Bifurcation Lesions (PERFECT) studies concluded that stenting technique had little impact on angiographic and clinical outcomes.[3] However, in contrast to other studies, the patients enrolled in these studies showed excellent angiographic and clinical outcomes. For example, the 1-year incidence of major adverse cardiovascular events (MACE) was less than 10% CONTACT Young-Hak Kim © 2015 Taylor & Francis

[email protected]

KEYWORDS

Coronary bifurcation lesion; percutaneous coronary intervention; bifurcation stenting technique; stent optimization; single-stent technique; double-stent technique

regardless of the stenting technique, if periprocedural myocardial infarction (MI) was not considered. Given that higher rates of newer generation drug-eluting stents (DESs), final kissing balloon inflation (FKI) and intravascular ultrasound (IVUS) guidance are the major distinguishing features of the CROSS and PERFECT studies, customized tailoring and fitting of newer generation DESs for individual bifurcations are a potential explanation of the good outcomes of these studies. In this context, the entire process of bifurcation PCI, from stenting technique selection to postdeployment optimization, will be reviewed here, as well as the measures used to individualize the technique.

Single- versus double-stent techniques Clinical trials comparing single- versus doublestent techniques Bifurcation stenting usually starts with deciding whether the SB is to be stented or not. In the singlestent technique with provisional SB treatment, the main branch (MB) is stented first and the SB is only stented in the case of severe stenosis or flow limitation after MB stenting. On the other hand, the SB is routinely stented before or after MB stenting in the double-stent technique. A number of randomized trials have compared the two strategies for the treatment of coronary bifurcation lesions (Table 1). These studies are heterogeneous in

Trial Colombo et al. Pan et al. Nordic Ferenc et al. CACTUS DKCRUSH-II

No of patients (single/double) 22/63 47/44 207/206 101/101 173/177 185/185 Inclusion criteria for the SB ≥2.5 mm, and DS ≥ 50% ≥2.25 mm, and DS ≥ 50% ≥2.0 mm ≥2.25 mm ≥2.25 mm, and DS ≥ 50% ≥2.5 mm, and DS ≥ 50%

Reference diameter of the SB, mm (single/double) 2.1 ± 0.3/2.1 ± 0.3 2.5 ± 0.3/2.5 ± 0.2 2.6 ± 0.4/2.6 ± 0.3 2.39 ± 0.31/2.38 ± 0.37 2.16 ± 0.33/2.30 ± 0.31 2.29 ± 0.35/2.38 ± 0.32 61.0 ± 13.0/63.0 ± 12.0 63.4 ± 14.2/62.8 ± 14.7

Diameter stenosis of the SB, % (single/double) 46.2 ± 22.3/56.8 ± 17.5 64.0 ± 13.0/65.0 ± 14.0

*p < 0.05. DS: Diameter stenosis; MACE: Major adverse cardiovascular end point; MB: Main branch; SB: Side branch; TVF: Target vessel failure.

Year 2004 2004 2006 2008 2009 2011

Table 1. Studies comparing the single- and double-stent techniques. Angiographic restenosis (single/ double) 18.7%/28.0% 7.0%/20.0% 22.5%/16.0% 12.5%/13.5% 6.7%/4.6% (MB) 14.7%/13.2% (SB) 9.7%/3.8% (MB)* 22.2%/4.9% (SB)*

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2.9%/3.4% (6 months) 12.9%/11.9% (12 months) 15%/15.8% (6 months) 17.3%/10.3% (12 months)

MACE 13.6%/19.0% (6-month TVF)

230 J.-H. ROH AND Y.-H. KIM

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terms of the size and disease severity of enrolled SBs. The mean reference diameter of the SB ranges from 2.1 to 2.6, and diameter stenosis (DS) from 46.2 to 64.0%. In spite of significant variability in baseline angiographic characteristics, these studies consistently reported that the double-stent technique did not yield more favorable outcomes than the single-stent technique.[3–9] Furthermore, among these studies, the Nordic Bifurcation and British Bifurcation Coronary Study: Old, New and Evolving Strategies (BBC ONE) trials reported poor outcomes for the double-stent technique. In the Nordic Bifurcation study, the double-stent technique prolonged procedure and fluoroscopic times, and increased the rate of procedure-related biomarker elevation.[9] The BBC ONE trial concluded that the doublestent technique resulted in higher rates of in-hospital and 9-month MACE, and this difference was largely driven by periprocedural MI.[7] A meta-analysis of the above randomized trials found that the risk of MI and stent thrombosis increased with the double-stent technique, despite similar rates of death and target lesion revascularization (TLR).[10] Likewise, Zimarino et al. conducted a meta-analysis of 12 major bifurcation studies including 6961 patients and showed that the doublestent technique was associated with an increased risk of MI, likely driven by stent thrombosis.[11] Based on these results, the single-stent strategy is currently recommended as the preferred technique for most bifurcation lesions by guideline-writing authorities.[2] The studies underlying the current recommendations included considerable numbers of non-true bifurcations and bifurcations with an SB diameter less than 2.5 mm (Table 1). Therefore, data on the efficacy of the double-stent technique in bifurcations with large and severely diseased SBs are still limited. In the Double Kissing Crush versus Provisional Stenting Technique for Treatment of Coronary Bifurcation Lesions (DKCRUSH-II) trial, 370 true bifurcation lesions, whose SBs ranged from 2.5 to 4.0 mm, were randomly assigned to the double kissing (DK)-crush or singlestent technique. Although there was no difference in the 1-year MACE rate between the two groups, the DKcrush technique was associated with a significant reduction in TLR and target vessel revascularization. [12] Recently, Chen et al. developed a model for discriminating complex bifurcations at a higher risk of MACE that consists of two major criteria (for distal left main bifurcations: SB percentage DS ≥ 70 and SB lesion length ≥ 10 mm; for non-left main bifurcations: SB DS ≥ 90% and SB lesion length ≥ 10 mm).[13] After analyzing 3660 prospectively enrolled patients, whose bifurcations were Medina 1, 1, 1 or 0, 1, 1 and with an SB diameter more than 2.5 mm, they showed that the

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double-stent technique for complex lesions elicited a lower rate of cardiac death and in-hospital MACE. The results of the above two studies may suggest the existence of some point along the spectrum of bifurcation lesions – ranging from bifurcations with small and healthy SBs to those with large and severely diseased SBs – beyond which outcomes are improved by the double-stent technique. However, some interventionists adopt the single-stent technique regardless of the SB diameter and DS, with some reporting acceptable outcomes with this strategy. Vaquerizo et al. reported 2year outcomes of 291 patients with distal left main bifurcation lesions that were treated with the singlestent technique regardless of the bifurcation type: 61.8% had angiographically significant SB stenosis, and the mean reference diameter of SB was 2.81 (SD: 0.45).[14] At the 2-year follow-up, the cardiac death, Qand non-Q-wave MI rates were 5.4, 0.9 and 3.1%, respectively, and MACE occurred in 15.8%. The randomized Nordic-Baltic IV (SB diameter ≥ 2.75 mm and DS ≥ 50%) and European Bifurcation Club II (SB diameter ≥ 2.50 mm and DS ≥ 50%) trials may provide further information on the role of the double-stent technique in bifurcation lesions with large and severely diseased SBs.

Choice between single- and double-stent techniques Despite comparable outcomes between the single- and double-stent techniques, bailout stenting of compromised SBs is often accompanied by more complex procedures than the planned double-stent technique. Moreover, Hahn et al. analyzed the Coronary Bifurcation Stenting (COBIS II) registry and reported that the blood flow of 14 of 187 occluded SBs was still not restored after SB intervention.[15] Therefore, the correct choice between the single- and doublestent techniques before the start of the procedure helps to maximize their own merits: the simplicity and swiftness of the single-stent technique versus the better technical results and avoidance of bailout SB stenting with the double-stent technique. In order to decide whether the SB should be stented provisionally or electively, its significance should be evaluated and the difficulty required to rewire it and the probability of its occlusion after MB stenting should be predicted. The significance of the SB often translates into the amount of viable myocardial mass supplied by it and is represented by its diameter and length. A quantitative relation between SB diameter and length and the size of the supplied myocardium has been established in swine.[16,17] The characteristics that

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cause difficulties in SB wiring have not been discovered in the relevant clinical trials, but are derived from expert consensus. Known angiographic predictors of difficult SB wiring are severe calcifications involving the proximal MB and/or ostial SB, severe stenosis in the proximal MB, tortuosity in the proximal MB, severe stenosis of the SB ostium and flow less than TIMI 3 in the SB.[18] In addition, a wide angle between the distal MB and SB has been considered an important predictor of difficult SB wiring.[18] Indeed, SB wiring is usually easy when the distal bifurcation angle is less than 70°, whereas access to the SB is usually more difficult for distal bifurcation angles of more than 70° and can be particularly difficult for angles exceeding 90°. Finally, in the rewiring phase, SB rewiring can be challenging when the SB flow is compromised or the SB is occluded after MB stenting. Predictors of SB occlusion after MB stenting have been recognized in many imaging modalities. Briefly, several studies identified the following angiographic predictors of SB compromise or occlusion: small reference SB diameter, ostial SB stenosis more than 50% before MB stenting, involvement of the SB origin within the lesion of the MB and a narrow distal bifurcation angle.[18] IVUS provides more detailed information on the geometric distribution of plaques. Furukawa et al. showed that plaques involving the SB ostium were a strong predictor of SB occlusion.[19] Coronary computed tomographic angiography has also been proven to be a useful modality for predicting SB occlusion. [20,21] Park et al. reported that plaque thickness in the SB side of the proximal MB, plaque thickness in the noncarinal side of the SB, SB lumen diameter and the DS of the SB on coronary computed tomographic angiography were predictors of SB occlusion.[21] Recently, Dou et al. developed a model predicting SB occlusion after MB stenting, named the Risk prEdiction of Side branch OccLusion in coronary bifurcation interVEntion scoring system.[22] The scoring system was constructed based on 1200 bifurcation lesions, and was proven to help to predict SB occlusion (Cstatistics: 0.77; 95% confidence interval [CI]: 0.69–0.86). Based on the abovementioned clinical trials and expert consensus, the characteristics of bifurcation lesions favoring single- and double-stent techniques are summarized in Table 2.

Single-stent techniques Protection of the SB and jailed wire technique Even if the single-stent technique is selected because the SB is of less significance, jailing of the insignificant

Table 2. Anatomical features favoring the single- or doublestent technique. Single-stent technique

Double-stent technique

Anatomical features Insignificant stenosis at the SB ostium Small SB Narrow-angled bifurcation No concomitant disease in the SB Focal disease in the SB Absence of complex anatomy impeding SB rewiring (severe calcifications involving the proximal MB and/ or ostial SB, severe tortuosity in the proximal MB) Plaque predominantly distributed at the opposite side of the SB Absence of severe stenosis involving the POC Significant stenosis at the SB ostium Large SB Wide-angled bifurcation Concomitant disease in the SB Diffuse disease in the SB Complex anatomy impeding SB rewiring Plaque predominantly distributed at the side of the SB Severe stenosis involving the POC

MB: Main branch; POC: Polygon of confluence; SB: Side branch.

SB can cause poor outcomes. The occlusion of an SB more than 1.0 mm in diameter has been associated with a 14% incidence of MI,[23,24] and an SB more than 2.0 mm can be accompanied by a large periprocedural MI.[25] In addition, Hahn et al. showed in the COBIS II registry that cardiac death, MI and stent thrombosis occurred more frequently in patients with SB occlusion.[15] For these reasons, the guide wire should be placed within SBs at a high risk of jailing to protect them, and the wire should be left until the MB procedure is completed. In the case of SB occlusion, the jailed SB wire acts as a marker for the obliterated SB ostium, facilitates rewiring of the SB by straightening the angle between the proximal MB and SB, and maintains the blood flow to the compromised SB. In addition, balloon inflation of the SB ostium can be applied using the jailed wire under the MB stent, if rewiring the SB is not possible.[18] In the COBIS II registry, the blood flow to the occluded SB was more frequently restored in the SBs with a jailed SB wire than those without wire protection.[15] Brunel et al. identified nonuse of the jailed wire technique as an independent predictor of poor outcome in the multicenter provisional T-stenting for coronary bifurcation lesion prospective evaluation study.[26]

Rate of SB jailing and its functional significance Although SB jailing after MB stenting is not infrequently encountered when performing the single-stent technique, the definition of a compromised SB is still arbitrary,

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leading to variability in its incidence across clinical studies. In randomized studies comparing the single- and double-stent techniques, the cross-over from the singleto double-stent technique ranged from 2.1 to 51.2%.[3– 9] The study by Colombo et al. defined a suboptimal result as residual stenosis of the SB ≥ 50%, resulting in the highest cross-over rate (51.2%).[5] On the other hand, the Nordic trial adopted a very conservative approach, in which only flow limitation (TIMI < 3), not residual stenosis, was considered an indication for SB intervention, reporting a lower cross-over rate (4.3%).[9] However, given the results of studies investigating the functional significance of jailed SBs using the fractional flow reserve (FFR), neither angiographic DS nor flow limitation seems to be able to reliably estimate the functional significance of jailed SBs.[27–29] Ahn et al. enrolled 241 bifurcations whose MB was stented first and measured the SB FFR in 230 of them.[27] Although none of these SBs had flow limitation (TIMI = 3), 41 (17.8%) were functionally significant (FFR ≤ 0.80). Moreover, the FFR was ≤0.80 in only 19 of 67 SBs (28.4%) with DS ≥ 50% by quantitative coronary angiography. The correlation between the FFR and DS by quantitative coronary angiography was also poor (r = – 0.21, p = 0.002). Although the incidence of functionally significant jailing varies across the studies, from 18 to 43%,[27–29] presumably due to the heterogeneity of SB stenosis severity, it is evident that a considerable number of angiographically jailed SBs have no hemodynamic significance.

Bailout stenting of jailed SB When the single-stent technique is used, major SB dissections or compromised SB flow are inevitably treated with SB stenting. However, in the case of nonflow limiting stenosis of the SB, the indication for SB stenting remains to be clarified. Despite accumulating evidence supporting the superiority of ischemia-guided revascularization over angiography-guided revascularization, data on FFRguided jailed SB revascularization are limited. Koo et al. enrolled 110 bifurcations treated with the provisional strategy, and measured the SB FFR in 91 of them.[30] Based on an FFR < 0.75, 26 SBs were treated with balloon angioplasty, and the FFR was restored in 92% of them (FFR ≥ 0.75). There was no difference in the 9-month MACE rate between these patients and the angiography-guided intervention group, which was separately selected from their PCI database. Recently, Chen et al. reported the results of the DKCRUSH-VI trial, which was the first randomized study to compare the outcomes of FFR- and angiography-guided provisional SB stenting for true bifurcation lesions.[31] A total of 320 bifurcations

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were enrolled, and randomly assigned to either of the two strategies in a 1:1 ratio. The SBs were stented in the case of a TIMI flow < 3, ostial SB stenosis ≥ 70%, or dissection in the angiography-guided group, and an SB FFR < 0.80 in the FFR-guided group. Although there was no difference in the 1-year MACE rate between the two groups (18.1 vs 18.1%; p = 1.0), fewer stents were used for the patients enrolled in the FFR-guided group (for MB, 1.56 ± 0.73 vs 1.56 ± 0.72, p = 1.00; for SB, 0.97 ± 0.31 vs 0.13 ± 0.34, p < 0.001). Moreover, 13-month follow-up angiography showed that restenosis involving the distal MB was significantly more common in the angiographyguided group (9.2 vs 1.7%; p = 0.01). Despite these advantages, dissemination of the FFR-guided approach might be limited by its technical difficulty: the SB FFR could not be measured in 9.4% of the FFR-guided group in that study.

Routine versus selective FKI Four randomized trials have evaluated the clinical effect of routine FKI after the single-stent technique.[3,32–34] The largest one is the Nordic-Baltic Bifurcation Study III, which enrolled 447 patients with bifurcation lesions and randomized them into routine FKI (n = 238) and no FKI (n = 239) groups after MB stenting with sirolimus-eluting stents.[33] At the 6-month follow-up, the rates of MACE were 2.1 and 2.5% (p = 1.00) in the routine and no FKI groups, respectively. Follow-up angiography was performed in 326 patients and showed that FKI significantly reduced angiographic SB restenosis (7.9 vs 20.2%; p = 0.039), especially in true bifurcation lesions (7.6 vs 20.2%; p = 0.024). In the recently published CROSS study, Kim et al. enrolled 306 bifurcation lesions whose SBs showed a DS ≥ 50% and TIMI flow = 3 after MB stenting, and randomly assigned them into either a routine (n = 151) or no (n = 155) FKI group.[3] The primary end point was defined as the 8-month angiographic DS, which was 31.1 ± 14.5 and 34.9 ± 15.8 in the routine and no FKI groups (p = 0.074), respectively. On the other hand, in a real-world registry named the COBIS, 1065 patients were treated with the single-stent technique, which was completed with and without FKI (329 vs 736 patients, respectively).[35] During the median 22month follow-up, the FKI group had a higher incidence of MACE (10.0 vs 4.9%; p = 0.002) and TLR (9.1 vs 3.4%; p < 0.001), and showed a higher adjusted risk for MACE (adjusted hazard ratio [HR]: 2.13; 95% CI: 1.15–3.95; p = 0.02) and TLR (adjusted HR: 3.63; 95% CI: 2.00– 6.56; p < 0.001). Despite the comparable clinical efficacy of routine and selective FKI shown in the randomized studies, a potential

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harmful effect of FKI on MB has been indicated in several studies. In the COBIS registry, FKI was associated with a higher adjusted risk for MB-TLR (adjusted HR: 3.39; 95% CI: 1.86–6.19; p < 0.001). Moreover, after analyzing 253 patients treated with the single-stent technique in the TAXUS Japan Postmarket Surveillance Study, Yamawaki et al. reported a higher late loss and higher binary restenosis rate in the MBs of the FKI group (in-stent late loss, 0.7 ± 0.6; in-stent restenosis rate, 16.3%) than in those of the no FKI group (0.5 ± 0.6, 7.3%) (p < 0.01 and p = 0.05, respectively).[36] Likewise, Roh et al. analyzed the pooled patients of the CROSS and PERFECT studies and identified FKI as an independent predictor of MB restenosis in normal SB bifurcations treated with the single-stent technique.[37] In this group, restenosis after FKI predominantly occurred at the proximal MB, where two overlapping balloons could have exerted abnormally high pressure on the stents and vessel walls. Indeed, distortion of the stent scaffolding and an abnormal concentration of stress at the proximal MB caused by FKI have been documented by virtual bench testing and in vivo imaging in several studies.[38–40] An ex vivo bench test showed that FKI caused elliptic deformation of the proximal MB, and reduced the metal-to-artery ratio and the potential drug delivery in this segment.[39] Foin et al. showed that the elliptic deformation caused by FKI induced higher stress concentration in the proximal MB, and was associated with incomplete stent apposition at the proximal stent edge.[38] Rahman et al. first showed elliptic overexpansion in the proximal MB by in vivo IVUS imaging. In that study, the stented MBs of 22 bifurcation lesions were investigated by IVUS before and after FKI, and the stent symmetry index decreased to a greater extent after FKI than after MB stenting (from 0.88 ± 0.04 to 0.81 ± 0.06, p < 0.01).[40] For these reasons, FKI should not be performed routinely after the single-stent technique. Based on a study reporting that FKI reduced the proportion of functionally significant SB stenosis from 30 to 5% in tightly narrowed SBs (DS ≥ 75% or TIMI flow < 3) after MB stenting,[30] an SB with DS ≥ 75% after MB stenting is the guideline-recommended indication for FKI.[2]

Double-stent techniques There are a number of bifurcation stenting techniques currently available, which are systematically categorized by the MADS classification system.[41] Of these techniques, the double-stent techniques can be categorized into two groups according to whether the MB or SB is first stented. As mentioned above, SB stenting through the side of the MB stent is difficult and often accompanied with complex techniques and devices, such as pullback wiring and reverse wire techniques, proximal optimization technique (POT) and specially designed

microcatheters.[18] Moreover, in spite of these procedures, failure of rewiring or device passage through the side of the MB stent is relatively common. For example, in the DKCRUSH-VI study, among a total of 320 SBs, 91 were indicated to be stented after MB stenting, but 17 (18.3%) could not be stented.[31] Therefore, for a planned double-stent technique, the SB is recommended to be stented prior to the MB stenting. On the other hand, for provisional SB stenting, T-stenting, and culotte and internal crush techniques can be used. In contrast to the single-stent technique, the doublestent technique frequently requires simultaneous introduction of the two balloons or stents, and thus requires specific consideration regarding the selection of an appropriately sized guiding catheter. With low-profile balloons, the two balloons can be inserted inside a large-lumen 6-Fr guiding catheter. If two stents have to be introduced simultaneously, there are some limitations to be understood. A 6-Fr guiding catheter allows only one stent to be inserted through it at a time, and is, therefore, compatible with certain techniques, such as T-stenting, the reverse crush and the step crush. On the other hand, the conventional crush, V-stenting and simultaneous kissing stent techniques cannot be performed unless the guiding catheter is 7 Fr or more. Except for the DK-crush technique, which has been associated with a lower risk of MACE compared with the culotte technique,[42] no double-stent techniques have been proven to be superior to the others. Nevertheless, because each double-stent technique has its own strengths and weaknesses (Table 3), it is recommended to master more than one technique to deal with a variety of coronary bifurcations.

T-stenting When the MB is planned to be stented first, T-stenting is the most commonly used technique to stent the SB. After MB stenting, the SB is rewired and dilated with the balloon to reopen the SB ostium covered by the MB stent. In an attempt to minimize the potential gap, the proximal end of the SB stent should be precisely positioned at the SB ostium. To correct the scaffold distortion caused by the ballooning and stent implantation through the side of the MB stent, the procedure should be completed with FKI. Regardless of the efforts exerted to precisely place the SB stent, T-stenting can leave an uncovered area at the noncarinal side of the SB wall, which is more likely when the bifurcation angle approaches 0°. Therefore, T-stenting is considered to be appropriate for near 90° angled bifurcations. The T and protrusion (TAP) is a modification of the T-stenting technique that allows intentional minimal protrusion of

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Table 3. Advantages and disadvantages of different double-stent techniques. T-stenting Classic crush Mini-crush

DK-crush

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Culotte

Advantages Better coverage of the SB ostium with a bifurcation angle approaching 90° No need for additional rewiring after SB stenting to perform FKI Relatively simple Guarantee of SB patency during the entire procedure Good coverage of the SB ostium Minimized multilayer strut Good scaffolding at the SB ostium and facilitated FKI (compared with the classic crush) Compatible with a 6-Fr guiding catheter Precise and easy handling of each stent

Disadvantages Potential gap at the SB ostium Protrusion of the SB stent into the MB (in the case of TAP) Difficult, and potentially suboptimal FKI Need for a guiding catheter larger than 7 Fr Multilayer strut in the proximal MB Multilayer strut, though minimized, is still left

Good scaffolding at the SB ostium

Complex procedures accompanied by additional kissing balloon inflation Multilayer strut, though minimized, is still left

Facilitated FKI Compatible with a 6-Fr guiding catheter Precise and easy handling of each stent Compatible with a 6-Fr guider Independent of bifurcation angle Predictable scaffolding

DK mini-culotte

Minimized multilayer strut Low risk for acute closure of the MB

Simultaneous kissing stenting

Guaranteed patency of both branches during the entire procedure No need to recross any stent for FKI Quick and simple

Leaves a multilayer strut Potential acute closure of the MB Need for rewiring of both branches across the side of the stent Complex procedures accompanied by additional kissing balloon inflation Multilayer strut, though minimized, is still left Need for rewiring both branches across the side of the stent Non-stented gap in the proximal MB Need for a guiding catheter larger than 7 Fr Leaves long metallic carina Potential overdilatation of the proximal MB Diaphragmatic membrane formation on the interface between the two stents Difficulty to position a stent proximal to the double-barrel

FKI: Final kissing balloon inflation; MB: Main branch; SB: Side branch; TAP: T-stenting and protrusion.

the SB stent (1–2 mm) into the MB. With this protrusion, the SB ostium can be fully covered by the SB stent, regardless of the bifurcation angle. The advantage of Tstenting lies in its simplicity. Contrary to the internal crush and culotte technique, in which the SB (for the former) or the MB (for the latter) should be rewired to perform FKI after SB stenting, T-stenting has no need for additional rewiring after SB stenting, which makes this technique the simplest of the MB first double-stent techniques.

Crush technique To overcome the incomplete coverage of the SB ostium caused by T-stenting, the crush technique was first introduced by Colombo et al., as the modified T-stenting technique with crushing.[43] In this technique, the two stents are simultaneously positioned in the MB and SB, with the proximal marker of the SB stent 4–5 mm retracted into the MB. After the SB stent deployment and the retrieval of its balloon and wire, the MB stent is inflated, flattening the protruding portion of the SB stent against the MB wall. Wire recrossing and balloon dilation of the SB, and then FKI should be performed to optimize the scaffold at the polygon of confluence (POC). In addition to near-perfect coverage of the SB ostium, the main

advantage of the crush technique is in guaranteeing the patency of the SB ostium during the entire procedure. This feature makes the crush technique the preferred approach in the case of functionally important SBs and/ or difficult SB wiring. On the other hand, multilayer struts piled on the SB ostium and MB walls are the main drawback. Overlapping of DESs is known to cause reduced strut endothelialization,[44,45] which potentially becomes a nidus for thrombus formation. In addition, double-layer struts covering the SB ostium make the FKI procedure difficult and incomplete. The mini-crush technique was conceived in an attempt to minimize the multilayer struts left on the proximal MB wall by the conventional crush technique.[46] Compared with the conventional technique, the mini-crush technique adopts a minimal retraction of the SB stent into the proximal MB wall so that the proximal marker of the SB stent is placed 1–2 mm proximal to the carina. According to the first description of the mini-crush technique, the balloon catheter is located in the MB to crush the protruding segment of the SB stent. The remaining steps are performed in the same way as the conventional crush technique. Ormiston et al. compared bench-deployed stents with the conventional and mini-crush techniques, and reported that the mini-crush technique minimized the residual stenosis of the SB ostium (36 vs 47%; p = 0.002).[47]

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Costa et al. reported that incomplete crushing, defined as incomplete apposition of the SB or MB stent struts against the MB wall proximal to the carina, was observed on IVUS in 60% of 20 non-left main bifurcations treated with the conventional crush technique.[48] To improve stent apposition and facilitate FKI, the DK-crush technique, as a variant of the mini-crush technique, incorporates additional kissing balloon inflation of the crushed SB stent before MB stenting. In contrast to the conventional or mini-crush technique, where the guide wire and balloon catheter should recross the SB ostium covered with a double-layer metal strut, the additional kissing balloon inflation adopted in the DK-crush technique leaves a single-layer metal strut to be recrossed for FKI, and facilitates FKI. Moreover, a single-layer strut is more easily cleared by FKI, resulting in a wider metallic SB ostium, compared with the double-layer strut in the conventional or mini-crush technique. Chen et al. reported that the DK-crush technique reduced the incomplete crush rate (39.5 vs 81.3%; p = 0.004) and optimized the scaffolding at the POC (better symmetry index at the proximal MB and larger minimal lumen area at the SB ostium), compared with the conventional crush technique.[49] Another advantage of the DKcrush technique is its compatibility with a 6-Fr guiding catheter, which is attributed to no need for simultaneous introduction of the two stents. This feature enables the mini- and DK-crush techniques to be performed via the radial artery. Moreover, sequential introduction of each stent allows their more precise handling. However, the additional kissing balloon inflation possibly makes the procedure more complex. The crush technique used for the provisional SB stenting is called the internal (or reverse) crush technique. Before deployment of the SB stent, all procedural steps are identical to those of the TAP technique. Instead of 1–2 mm retraction of the SB stent in the TAP technique, the internal crush technique requires 2–3 mm retraction, with the balloon catheter located in the MB to crush the protruding portion of the SB stent. After crushing, rewiring and ballooning of the SB and FKI should be performed.

Culotte technique The culotte technique is begun with the wiring and predilation of both branches. The first stent is placed so that it spans from the proximal MB to the SB, and deployed. The nonstented distal MB is then rewired through the cells of the first stent, and dilated. After retrieval of the jailed MB wire, the second stent is implanted in the MB, with the proximal portion overlapping the first stent. The SB is rewired and dilated, and FKI is performed. This technique is suitable for all

bifurcation angles and provides near-perfect coverage of the SB ostium. However, it can cause intraprocedural acute closure of the MB after the first stenting, which might be catastrophic with distal left main disease. Another disadvantage is that, like the crush technique, it leaves a double-layer stent in the proximal MB, potentially leading to delayed endothelialization and subsequent stent thrombosis. Lastly, it is difficult and timeconsuming to rewire both branches through the stent strut, and the first stent having a closed-cell platform or much smaller size than the second stent might limit maximal expansion of the second stent, with consequent underexpansion at the distal MB ostium. The culotte technique can be used for provisional SB stenting by simply changing the stenting sequence of the two branches. Recently, Fan et al. introduced the DK mini-culotte technique, which was conceived to overcome the drawbacks of the conventional culotte technique.[50] After predilation of both the branches, the balloon catheter and first stent are introduced into the MB and SB, respectively. To minimize the length of the double-layer stent in the proximal MB, the first stent is positioned with a minimal protrusion (1–2 mm) into the MB. The first stent is deployed and the balloon catheter in the MB is left to be jailed by the first stent. In the case of acute closure of the MB, the jailed balloon maintains blood flow and is used to reopen the MB. The MB is rewired via the cells of the first stent, and the jailed balloon and wire are retrieved. Kissing balloon inflation is performed before the second stenting, which makes up the DKs with FKI. The remaining steps are performed in the same way as the conventional culotte. In the study by Fan et al., as compared with the provisional T-stenting, the DK mini-culotte technique was associated with a similar 1-year MACE rate (13.6 vs 4.55%; p = 0.127), but a lower target vessel revascularization (12.12 vs 1.52%; p = 0.033) and SB restenosis rate (22.4 vs 5.6%; p = 0.014). The clinical efficacy of the culotte technique was compared with the crush technique in the Nordic Stent Technique Study.[51] At 3-year follow-up, MACE rates were comparable between the crush and culotte groups. Although the mechanism was not clear, there was a trend to increase definite stent thrombosis in the culotte group (1.4 vs. 4.7% in the crush and culotte groups, respectively; p = 0.09). Interestingly, FKI reduced the long-term rates of MACE and stent thrombosis.

Simultaneous kissing stent technique This technique is performed by simultaneous introduction and deployment of the two stents in the MB and SB. Simultaneous deployment of the two stents inevitably forms a double-barrel in the proximal MB, the

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length of which discriminates between the simultaneous kissing stent technique and V-stenting, the former with a double-barrel ≥ 5 mm, and the latter with a minimal or no double-barrel. The main advantage of this technique lies in its safety and swiftness. During the procedure, this technique guarantees the patency of both branches. In addition, there is no need for wire recrossing of any branch. However, formation of the double-barrel can cause several problems. First, because the two cylindrical stents cannot circumferentially cover the entire proximal MB wall, nonstented gaps are inevitable adjacent to the interface between the two stents. Second, Kim et al. showed that the interface between the two stents turned into a linear membranous structure dividing the proximal MB lumen at a 6-month follow-up angiography in 47% of 36 patients treated with this technique.[52] Finally, positioning of a stent proximal to the double-barrel is problematic. There are two options when placing a stent proximally: the stent is deployed so as to allow a small gap between the new stent and double-barrel, and the simultaneous kissing stent technique can be converted into the crush technique. For the conversion to the crush technique, the new stent is inflated in the MB stent crushing the SB stent against the MB wall, which inevitably leaves four-layer stent struts in the proximal MB. Although, for these reasons, this technique is not recommended as a routine double-stent technique,[2] distal left main bifurcations with short and disease-free shafts are considered to be appropriate for this technique. In addition, its technical simplicity and speed leave room for its use in patients with a highly unstable status, such as with ST-elevation MI involving distal left main bifurcations.

Optimization Sizing of coronary stents To tailor a coronary stent to a bifurcation, understanding of the anatomical characteristics of coronary bifurcations is critical. Mathematical models to explain the relationship between the reference sizes of bifurcating vessels have been developed by Murray, Finet, and Huo and Kassab.[53–55] Of the three equations, the Huo– Kassab model has been found to be in agreement with all bifurcation types and is commonly recommended [54]: 7=3

7=3 D7=3 p ¼ Dd þ Ds

where Dp, Dd and Ds are the diameters of the proximal and distal MB, and the SB, respectively. Given that most bifurcation stenting techniques involve the

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implantation of one coronary stent spanning from the proximal to the distal MB, the most important implication of these models is that coronary bifurcations are always accompanied by a step down in the reference diameter from the proximal to distal MB. Foin et al. showed the maximally achievable diameters of current DES platforms, and that strut deformations are caused by overexpansion.[56] For example, a stent that is just the size of the distal MB would not provide complete apposition to the proximal MB or overstretch to expand adequately. According to the study by Foin et al., overexpansion of a DES enlarges the cells and straightens the crowns. As a result, enlarged gaps between stent struts potentially cause plaque prolapse and impaired drug delivery. Moreover, excessive structural changes from the original design may damage the polymer coating. On the other hand, a stent that is just the size of the proximal MB would cause a barotrauma or edge dissection in the distal MB. For these reasons, the MB stent should be sized according to the distal MB reference diameter, keeping in mind its maximally achievable diameter.[2]

Proximal optimization technique The POT is a method of expanding the MB stent from the proximal edge to just proximal to the carina, using a short oversized balloon, and its potential beneficial effects have been reported in several studies. First, the POT is used to enhance stent apposition in the proximal MB, especially for bifurcations with a large discrepancy in reference diameter between the proximal and distal MB. Second, the POT modifies the SB ostium to take off more obliquely, facilitating SB access in the case of difficult SB rewiring.[2] Finally, the POT can correct elliptical deformation of the proximal MB scaffold caused by kissing balloon inflation. Foin et al. showed, using 14 stents deployed in silicone phantoms, that the POT reduced the stent eccentricity and percentage of malapposed struts in the proximal MB, which were caused by kissing balloon inflation.[57] However, the clinical efficacy of the POT is yet to be proven in a relevant clinical trial.

IVUS guidance As a kind of radiologic luminal imaging modality, coronary angiography is unable to visualize the atherosclerotic involvement of the arterial wall. As a result, reference vessel diameters are underestimated in the case of diffuse disease or remodeling. On the other hand, IVUS allows a real-time, tomographic delineation of the intima and adventitia of an arterial wall, enabling

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more accurate measurement of the reference diameter. Information on plaque burden and its distribution help to predict the possibility of SB occlusion after the MB stenting, and to choose an appropriate stenting technique for a given bifurcation. Furthermore, some studies suggested that IVUS had a potential to predict the functional significance of the target stenosis.[58,59] At postprocedure, IVUS examination can reveal stent underexpansion and malapposition, which cannot be identified on coronary angiography. Indeed, IVUS guidance has been reported to improve outcomes, compared with angiography-guided bifurcation stenting. [60] Kim et al. analyzed a propensity-matched cohort comprising patients with non-left main bifurcation lesions that were treated under IVUS guidance (n = 487) and under angiography guidance (n = 487). They reported that IVUS guidance was associated with larger maximal stent diameters in both the MB and the SB, and lower cumulative incidences of a composite of death or MI (HR: 0.44; 95% CI: 0.12–0.96; p = 0.04).

Importance of FKI All SB interventions performed through the side of the MB stent distort the scaffold of the MB stent, especially at the POC.[61] Ormiston et al. deployed five kinds of stent in the MB of phantom bifurcations, and dilated the SB through the side of the deployed stent with different sized balloon catheters. They showed that SB ballooning deformed the MB stent just distal to the carina, which became greater with larger balloons, and was corrected after the performance of FKI. Although FKI in double-stent techniques has not been evaluated in randomized clinical studies, patients without FKI had consistently worse outcomes in the Nordic II trial [62] and in registries.[63,64] Therefore, all doublestent techniques, except for the simultaneous kissing stents technique, are recommended to be completed by FKI. As shown in the study by Costa et al., the minimal stent area is usually found at the SB ostium after the crush technique despite FKI performance.[48] To maximally enlarge the SB ostium, a two-step kissing postdilation was suggested by Ormiston et al.[47] The twostep kissing postdilation consists of high-pressure balloon postdilation of the SB and subsequent FKI. They compared this technique with a single FKI and found that SB ostial stenosis after crush stenting was minimized by two-step kissing postdilation. Based on these results, the current guidelines state that for the doublestent technique, high-pressure dilations of both ostia (preferably the SB first) followed by a lower pressure kissing inflation are required for full stent expansion.[2]

Other technical aspect to be considered for FKI is the selection of balloon diameters. Several rules have been proposed to appropriately select the diameters of the balloons for simultaneous inflation during FKI, one of which was recently validated in an IVUS study by Morino et al. [65]: R2 ¼ D1 2 þ D2 2 where D1 and D2 are the diameters of MB and SB balloons, respectively, and R is the expected diameter of the two overlapping balloons. They showed this formula was useful for predicting resultant stent expansion following FKI. However, the clinical impact of technical specifications involved in FKI, such as balloon and vessel diameters, and inflating pressure, has not been sufficiently studied. In the study of Roh et al., there was no association between those technical specifications and angiographic restenosis.[37]

Special considerations for distal left main bifurcations Although the recent guideline still recommends coronary artery bypass grafting over PCI for revascularization of distal left main bifurcation lesions,[66] PCI has become an acceptable alternative by virtue of advances in devices and techniques. Because of different anatomical characteristics and amount of feeding myocardium, some considerations must be given to PCI of unprotected distal left main bifurcations. First, the left circumflex artery (LCX) is, in most cases, considered a major SB. Therefore, the double-stent technique is favored in the case of significant and extended proximal LCX disease. In the absence of a randomized study comparing the single- and doublestent techniques, the former have been considered the default treatment strategy for left main bifurcation lesions based on nonrandomized studies [67,68] and an extrapolation from the results of non-left main bifurcation trials. However, considering the noticeable rate of SB occlusion after MB stenting,[15] which would lead to circulatory collapse in the case of LCX, the double-stent technique is still advocated for bifurcations with a high probability of SB occlusion. Second, wider bifurcation angles can cause difficulty in SB wiring. Pflederer et al. assessed the natural distribution of four main coronary artery distal bifurcation angles by 16-slice multidetector computed tomography in 100 patients with suspected coronary artery disease, reporting the following average values: 80 ± 27° for LAD/ LCX, 46 ± 19° for LAD/Diagonal 1, 48 ± 24° for LCX/OM1 and 53 ± 27° for PDA/PLA.[69] Therefore, SB first doublestent techniques should be considered in expectation of a difficult SB wiring for left main bifurcations. Third, IVUS imaging is of particular value in PCI of the left main

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bifurcation because of its distinctive anatomic features. An angiographic assessment of reference vessel diameter is difficult due to the shorter length of the left main shaft, where the disease would often involve its entire length. Moreover, compared with non-left main bifurcations, left main bifurcations are usually accompanied by a greater discrepancy in the reference diameter between the proximal and distal MBs due to relatively larger SBs. Finally, angiographic classification of left main bifurcation lesion is commonly inaccurate, which potentially leads to inappropriate selection of stenting strategies.[70] Therefore, accurate evaluation of anatomic characteristics using IVUS is critical in preimplantation decision-making and postimplantation optimization. Finally, the POT may be of particular importance in the treatment of left main bifurcations. A greater size discrepancy between the proximal and distal MB increases the need for the POT in stent optimization. Furthermore, proper apposition of the MB stent provided by the POT prevents collision of the guiding catheter and unsupported stent, and abluminal rewiring by a second wire.

Conclusions Individualized bifurcation stenting should start with accurate evaluation of a given coronary bifurcation. For that purpose, IVUS is a useful modality because it provides information on reference diameter, and plaque burden and distribution, which cannot be obtained from conventional angiography. Based on this information, appropriately sized stents and a proper technique to implant them must be selected. For most bifurcations, the single-stent technique is the default treatment strategy. However, the doublestent technique is still a viable option for coronary bifurcations with large and severely diseased SBs. After stent implantation, stent struts should be optimized by postdilation, FKI and/or POT. At postprocedure, IVUS examination can reveal stent underexpansion and malapposition, and help with making a decision on performance of additional optimization steps.

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of their anatomy, and plaque burden and distribution, it is not surprising that previous studies, which compared bifurcation stenting techniques without regard to the characteristics of a given bifurcation, showed disappointing results. Therefore, the bifurcation stenting technique should be selected according to anatomical and functional features of individual bifurcations. Another approach to individualize bifurcation stenting is to optimize the scaffold of stents deployed by a selected bifurcation stenting technique. A cylindrical coronary stent is inevitably accompanied by distortion, underexpansion and/or malapposition after deployment in a coronary bifurcation. Therefore, selection of appropriately sized stents and postdeployment optimization are essential in bifurcation stenting, which can be aided by IVUS imaging.

Five-year view In the next 5 years, the roles of the drug-coated balloon (DCB) and bioresorbable scaffold (BRS) are expected to increase in coronary bifurcation treatment. A DCB may be used as an alternative to conventional SB treatment. Although there is still a lack of evidence, a DCB may be helpful for preventing intimal growth caused by balloon injury without any additional DES implantation. Furthermore, problems with multilayer struts left by the crush and culotte techniques are expected to be resolved by using a BRS. However, Džavík et al. reported malapposition, distortion and disruption of 2-BRS deployed in bifurcation phantom models by various double-stent techniques.[71] Dedicated procedural technique using BRS for bifurcation lesions needs to be investigated. Furthermore, invention of scaffolds having thinner struts and better conformability is the prerequisite to be used for the double-stent technique. In spite of their conceptual plausibility and potential to simplify the procedure, data on their clinical efficacy are limited. More randomized trials comparing these devices with contemporary DES are necessary to validate their potential clinical benefit.

Expert commentary Although not infrequently encountered during PCI, coronary bifurcation lesions are challenging and associated with a higher rate of adverse events than nonbifurcation lesions. Much effort has been expended in trying to identify the optimal stenting technique for universal bifurcations, but this issue is still a matter of debate. However, considering the diversity of coronary bifurcations in terms

Financial & competing interests disclosure The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

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Key issues ● Current evidence and guidelines support the single-stent technique as the default treatment strategy for

coronary bifurcations. ● Previous studies comparing the single- and double-stent techniques included considerable numbers of

● ● ● ● ● ● ●

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bifurcations with small and mildly diseased side branches (SBs). Therefore, the efficacy of the double-stent technique in bifurcations with large and severely diseased SBs remains to be investigated. The double-stent technique is still a viable option for coronary bifurcations with large and severely diseased SBs. The benefit of routine use of the jailed wire technique outweighs its potential harmful effects. A considerable number of angiographically jailed SBs have no hemodynamic significance. For the single-stent technique, routine final kissing balloon inflation is not recommended. The functional significance of SB jailing should be taken into account, before bail-out stenting is determined. Main branch (MB) first double-stent techniques should be reserved for provisional SB stenting. There are a number of double-stent techniques with their own strengths and weaknesses. The MB stent should be sized according to the distal MB reference diameter, bearing in mind its maximally achievable diameter and subsequently induced deformations. IVUS imaging can guide pre-implantation decision-making and post-implantation optimization. For the double-stent technique, high-pressure dilation of both ostia (preferably the SB first) followed by a lower pressure kissing inflation are mandatory to achieve full stent expansion. The proximal optimization technique has been reported to have several beneficial effects. Because of different anatomical characteristics and amount of feeding myocardium, some considerations must be given to PCI of unprotected distal left main bifurcations.

References Papers of special note have been highlighted as: • of interest •• of considerable interest 1. Thomas MR, Hildick-Smith D, Louvard Y, et al. Percutaneous coronary intervention for bifurcation disease. A consensus view from the first meeting of the European Bifurcation Club. EuroIntervention. 2006;2:149–153. 2. Lassen JF, Holm NR, Stankovic G, et al. Percutaneous coronary intervention for coronary bifurcation disease: consensus from the first 10 years of the European Bifurcation Club meetings. EuroIntervention. 2014;10:545–560. •• Recent guidelines for the treatment of coronary bifurcations. 3. Kim Y-H, Lee J-H, Roh J-H, et al. Randomized comparisons between different stenting approaches for bifurcation coronary lesions with or without side branch stenosis. JACC Cardiovasc Interv. 2015;8:550–560. •• Recently published randomized studies comparing routine versus selective final kissing balloon inflation for bifurcations with normal side branches and single- versus double-stent techniques for those with diseased side branches. 4. 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 Crushing Technique Using Sirolimus-Eluting Stents) Study. Circulation. 2009;119:71–78. 5. Colombo A, Moses JW, Morice MC, et al. Randomized study to evaluate sirolimus-eluting stents implanted at

coronary bifurcation lesions. Circulation. 2004;109:1244– 1249. 6. Ferenc M, Gick M, Kienzle R-P, et al. Randomized trial on routine vs. provisional T-stenting in the treatment of de novo coronary bifurcation lesions. Eur Heart J. 2008;29:2859–2867. 7. 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;121:1235–1243. 8. Pan M, De Lezo JS, Medina A, et al. Rapamycin-eluting stents for the treatment of bifurcated coronary lesions: a randomized comparison of a simple versus complex strategy. Am Heart J. 2004;148:857–864. 9. 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;114:1955–1961. 10. Katritsis DG, Siontis GCM, Ioannidis JPA. Double versus single stenting for coronary bifurcation lesions a metaanalysis. Circ Cardiovasc Interv. 2009;2:409–415. 11. Zimarino M, Corazzini A, Ricci F, et al. Late thrombosis after double versus single drug-eluting stent in the treatment of coronary bifurcations: a meta-analysis of randomized and observational Studies. JACC Cardiovasc Interv. 2013;6:687– 695. 12. Chen S-L, Santoso T, Zhang -J-J, et al. A randomized clinical study comparing double kissing crush with provisional stenting for treatment of coronary bifurcation lesions: results from the DKCRUSH-II (Double Kissing Crush versus Provisional Stenting Technique for Treatment of Coronary

Downloaded by [Laurentian University] at 05:52 17 February 2016

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Bifurcation Lesions) Trial. J Am Coll Cardiol. 2011;57:914– 920. 13. Chen S-L, Sheiban I, Xu B, et al. Impact of the complexity of bifurcation lesions treated with drug-eluting stents: the DEFINITION Study (Definitions and impact of complEx biFurcation lesIons on clinical outcomes after percutaNeous coronary IntervenTIOn using drug-eluting steNts). JACC Cardiovasc Interv. 2014;7:1266–1276. 14. Vaquerizo B, Lefèvre T, Darremont O, et al. Unprotected left main stenting in the real world two-year outcomes of the French left main taxus registry. Circulation. 2009;119:2349–2356. 15. Hahn J-Y, Chun WJ, Kim J-H, et al. Predictors and outcomes of side branch occlusion after main vessel stenting in coronary bifurcation lesions: results from the COBIS II Registry (COronary BIfurcation Stenting). J Am Coll Cardiol. 2013;62:1654–1659. 16. Choy JS, Kassab GS. Scaling of myocardial mass to flow and morphometry of coronary arteries. J Appl Physiol. 2008;104:1281–1286. 17. Kassab GS, Bhatt DL, Lefèvre T, et al. Relation of angiographic side branch calibre to myocardial mass: a proof of concept myocardial infarct index. EuroIntervention. 2013;8:1461–1463. 18. Burzotta F, De Vita M, Sgueglia GA, et al. How to solve difficult side branch access? EuroIntervention. 2011;6: J72–J80. 19. Furukawa E, Hibi K, Kosuge M, et al. Intravascular ultrasound predictors of side branch occlusion in bifurcation lesions after percutaneous coronary intervention. Circ J. 2005;69:325–330. 20. Goto Y, Kawasaki T, Koga N, et al. Plaque distribution patterns in left main trunk bifurcations: prediction of branch vessel compromise by multidetector row computed topography after percutaneous coronary intervention. EuroIntervention. 2012;8:708–716. 21. Park JJ, Chun EJ, Cho Y-S, et al. Potential predictors of side-branch occlusion in bifurcation lesions after percutaneous coronary intervention: a coronary CT angiography study. Radiology. 2014;271:711–720. 22. Dou K, Zhang D, Xu B, et al. An angiographic tool for risk prediction of side branch occlusion in coronary bifurcation intervention: the RESOLVE score system (Risk prEdiction of Side branch OccLusion in coronary bifurcation interVEntion). JACC Cardiovasc Interv. 2015;8:39–46. 23. Arora RR, Raymond RE, Dimas AP, et al. Side branch occlusion during coronary angioplasty: incidence, angiographic characteristics, and outcome. Cathet Cardiovasc Diagn. 1989;18:210–212. 24. Meier B, Gruentzig AR, King III SB, et al. Risk of side branch occlusion during coronary angioplasty. Am J Cardiol. 1984;53:10–14. 25. Chaudhry EC, Dauerman KP, Sarnoski CL, et al. Percutaneous coronary intervention for major bifurcation lesions using the simple approach: risk of myocardial infarction. J Thromb Thrombolysis. 2007;24:7–13. 26. Brunel P, Lefevre T, Darremont O, et al. Provisional T-stenting and kissing balloon in the treatment of coronary bifurcation lesions: results of the French multicenter “TULIPE” study. Catheter Cardiovasc Interv. 2006;68:67–73.

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27. Ahn J-M, Lee J-Y, Kang S-J, et al. Functional assessment of jailed side branches in coronary bifurcation lesions using fractional flow reserve. JACC Cardiovasc Interv. 2012;5:155–161. • This study reported the incidence of functionally significant jailed side branches after main branch stenting. 28. Koo B-K, Kang H-J, Youn T-J, et al. Physiologic assessment of jailed side branch lesions using fractional flow reserve. J Am Coll Cardiol. 2005;46:633–637. 29. Koo B-K, Waseda K, Kang H-J, et al. Anatomic and functional evaluation of bifurcation lesions undergoing percutaneous coronary intervention. Circ Cardiovasc Interv. 2010;3:113–119. 30. Koo B-K, Park K-W, Kang H-J, et al. Physiological evaluation of the provisional side-branch intervention strategy for bifurcation lesions using fractional flow reserve. Eur Heart J. 2008;29:726–732. 31. Chen S-L, Ye F, Zhang J-J, et al. Randomized comparison of FFR-guided and angiography-guided provisional stenting of true coronary bifurcation lesions: the DKCRUSH-VI (Double Kissing Crush Versus Provisional Stenting Technique for Treatment of Coronary Bifurcation Lesions VI) Trial. JACC Cardiovasc Interv. 2015;8:536–546. 32. Korn HV, Yu J, Ohlow MA, et al. Interventional therapy of bifurcation lesions: a TIMI flow-guided concept to treat side branches in bifurcation lesions—a prospective randomized clinical study (Thueringer bifurcation study, THUEBIS study as pilot trial). Circ Cardiovasc Interv. 2009;2:535–542. 33. Niemelä M, Kervinen K, Erglis A, et al. Randomized comparison of final kissing balloon dilatation versus no final kissing balloon dilatation in patients with coronary bifurcation lesions treated with main vessel stenting: the Nordic-Baltic Bifurcation Study III. Circulation. 2011;123:79–86. 34. Pan M, Medina A, Suárez de Lezo J, et al. Coronary bifurcation lesions treated with simple approach (from the Cordoba & Las Palmas [CORPAL] Kiss Trial). Am J Cardiol. 2011;107:1460–1465. 35. Gwon H-C, Hahn J-Y, Koo B-K, et al. Final kissing ballooning and long-term clinical outcomes in coronary bifurcation lesions treated with 1-stent technique: results from the COBIS registry. Heart. 2012;98:225–231. 36. Yamawaki M, Muramatsu T, Kozuma K, et al. Long-term clinical outcome of a single stent approach with and without a final kissing balloon technique for coronary bifurcation. Circ J Off J Jpn Circ Soc. 2013;78:110–121. 37. Roh J-H, Lee J-H, Kim Y-H, et al. Procedural predictors of angiographic restenosis after bifurcation coronary stenting (from the choice of optimal strategy for bifurcation lesions with normal side branch and optimal stenting strategy for true bifurcation lesions studies). Am J Cardiol. 2015;116:1050–1056. 38. Foin N, Torii R, Mortier P, et al. Kissing balloon or sequential dilation of the side branch and main vessel for provisional stenting of bifurcations: lessons from microcomputed tomography and computational simulations. JACC Cardiovasc Interv. 2012;5:47–56. 39. Guérin P, Pilet P, Finet G, et al. Drug-eluting stents in bifurcations bench study of strut deformation and coating lesions. Circ Cardiovasc Interv. 2010;3:120–126. 40. Rahman S, Leesar T, Cilingiroglu M, et al. Impact of kissing balloon inflation on the main vessel stent volume,

Downloaded by [Laurentian University] at 05:52 17 February 2016

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J.-H. ROH AND Y.-H. KIM

area, and symmetry after side-branch dilation in patients with coronary bifurcation lesions: a serial volumetric intravascular ultrasound study. JACC Cardiovasc Interv. 2013;6:923–931. 41. Louvard Y, Thomas M, Dzavik V, et al. Classification of coronary artery bifurcation lesions and treatments: time for a consensus! Catheter Cardiovasc Interv Off J Soc Card Angiogr Interv. 2008;71:175–183. 42. Chen S-L, Xu B, Han Y-L, et al. Comparison of double kissing crush versus Culotte stenting for unprotected distal left main bifurcation lesions: results from a multicenter, randomized, prospective DKCRUSH-III study. J Am Coll Cardiol. 2013;61:1482–1488. 43. Colombo A, Stankovic G, Orlic D, et al. Modified T-stenting technique with crushing for bifurcation lesions: immediate results and 30-day outcome. Catheter Cardiovasc Interv. 2003;60:145–151. 44. Finn AV, Kolodgie FD, Harnek J, et al. Differential response of delayed healing and persistent inflammation at sites of overlapping sirolimus- or paclitaxel-eluting stents. Circulation. 2005;112:270–278. 45. Awata M, Kotani J, Uematsu M, et al. Serial angioscopic evidence of incomplete neointimal coverage after sirolimus-eluting stent implantation comparison with baremetal stents. Circulation. 2007;116:910–916. 46. Galassi AR, Colombo A, Buchbinder M, et al. Long-term outcomes of bifurcation lesions after implantation of drug-eluting stents with the “mini-crush technique.”. Catheter Cardiovasc Interv Off J Soc Card Angiogr Interv. 2007;69:976–983. 47. Ormiston JA, Webster MWI, Webber B, et al. The “Crush” technique for coronary artery bifurcation stenting: insights from micro-computed tomographic imaging of bench deployments. JACC Cardiovasc Interv. 2008;1:351–357. 48. Costa RA, Mintz GS, Carlier SG, et al. Bifurcation coronary lesions treated with the “Crush” technique: an intravascular ultrasound analysis. J Am Coll Cardiol. 2005;46:599–605. • This study investigated scaffolds on intravascular ultrasound after the crush technique. 49. Chen S-L, Mintz G, Kan J, et al. Serial intravascular ultrasound analysis comparing double kissing and classical crush stenting for coronary bifurcation lesions. Catheter Cardiovasc Interv Off J Soc Card Angiogr Interv. 2011;78:729–736. 50. Fan L, Chen L, Luo Y, et al. DK mini-culotte stenting in the treatment of true coronary bifurcation lesions: a propensity score matching comparison with T-provisional stenting. Heart Vessels. 2014. DOI:10.1007/ s00380-014-0611-7. [Epub ahead of print] 51. Kervinen K, Niemelä M, Romppanen H, et al. Clinical outcome after crush versus culotte stenting of coronary artery bifurcation lesions: the Nordic Stent Technique Study 36month follow-up results. JACC Cardiovasc Interv. 2013;6:1160–1165. 52. Kim Y-H, Park D-W, Suh I-W, et al. Long-term outcome of simultaneous kissing stenting technique with sirolimuseluting stent for large bifurcation coronary lesions. Catheter Cardiovasc Interv Off J Soc Card Angiogr Interv. 2007;70:840–846.

53. Finet G, Gilard M, Perrenot B, et al. Fractal geometry of arterial coronary bifurcations: a quantitative coronary angiography and intravascular ultrasound analysis. EuroIntervention J Eur Collab Work Group Interv Cardiol Eur Soc Cardiol. 2008;3:490–498. 54. Huo Y, Finet G, Lefèvre T, et al. Optimal diameter of diseased bifurcation segment: a practical rule for percutaneous coronary intervention. EuroIntervention. 2012;7:1310–1316. 55. Murray CD. The physiological principle of minimum work applied to the angle of branching of arteries. J Gen Physiol. 1926;9:835–841. 56. Foin N, Sen S, Allegria E, et al. Maximal expansion capacity with current DES platforms: a critical factor for stent selection in the treatment of left main bifurcations? EuroIntervention. 2013;8:1315–1325. • This study investigated the maximal expansion capacity of currently available drug-eluting stent platforms. 57. Foin N, Secco GG, Ghilencea L, et al. Final proximal postdilatation is necessary after kissing balloon in bifurcation stenting. EuroIntervention. 2011;7:597–604. 58. Waksman R, Legutko J, Singh J, et al. FIRST: fractional flow reserve and intravascular ultrasound relationship study. J Am Coll Cardiol. 2013;61:917–923. 59. Park S-J, Ahn J-M, Kang S-J, et al. Intravascular ultrasound-derived minimal lumen area criteria for functionally significant left main coronary artery stenosis. JACC Cardiovasc Interv. 2014;7:868–874. 60. Kim J-S, Hong M-K, Ko Y-G, et al. Impact of intravascular ultrasound guidance on long-term clinical outcomes in patients treated with drug-eluting stent for bifurcation lesions: data from a Korean multicenter bifurcation registry. Am Heart J. 2011;161:180–187. 61. Ormiston JA, Webster MWI, Ruygrok PN, et al. Stent deformation following simulated side-branch dilatation: a comparison of five stent designs. Catheter Cardiovasc Interv. 1999;47:258–264. 62. Maeng M, Holm NR, Erglis A, et al. Long-term results after simple versus complex stenting of coronary artery bifurcation lesions: Nordic Bifurcation Study 5-year follow-up results. J Am Coll Cardiol. 2013;62:30–34. 63. Biondi-Zoccai G, Sheiban I, Servi S, et al. To kiss or not to kiss? Impact of final kissing-balloon inflation on early and long-term results of percutaneous coronary intervention for bifurcation lesions. Heart Vessels. 2013 [cited 2014 Aug 5]. Available from: http://link.springer.com/10.1007/ s00380-013-0416-0. 64. Ge L, Airoldi F, Iakovou I, et al. Clinical and angiographic outcome after implantation of drug-eluting stents in bifurcation lesions with the crush stent technique: importance of final kissing balloon post-dilation. J Am Coll Cardiol. 2005;46:613–620. 65. Morino Y, Yamamoto H, Mitsudo K, et al. Functional formula to determine adequate balloon diameter of simultaneous kissing balloon technique for treatment of bifurcated coronary lesions: clinical validation by volumetric intravascular ultrasound analysis. Circ J Off J Jpn Circ Soc. 2008;72:886–892. 66. Authors/Task Force members, Windecker S, Kolh P, et al. 2014 ESC/EACTS guidelines on myocardial

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revascularization: the task force on myocardial revascularization of the European Society of Cardiology (ESC) and the European Association for Cardio-Thoracic Surgery (EACTS). Developed with the special contribution of the European Association of Percutaneous Cardiovascular Interventions (EAPCI). Eur Heart J. 2014;35:2541–2619. 67. Kim W-J, Kim Y-H, Park D-W, et al. Comparison of singleversus two-stent techniques in treatment of unprotected left main coronary bifurcation disease. Catheter Cardiovasc Interv. 2011;77:775–782. 68. Song YB, Hahn J-Y, Yang JH, et al. Differential prognostic impact of treatment strategy among patients with left main versus non–left main bifurcation lesions

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undergoing percutaneous coronary intervention: results from the COBIS (Coronary Bifurcation Stenting) Registry II. JACC Cardiovasc Interv. 2014;7:255–263. 69. Pflederer T, Ludwig J, Ropers D, et al. Measurement of coronary artery bifurcation angles by multidetector computed tomography. Investig Radiol. 2006;41:793–798. 70. Oviedo C, Maehara A, Mintz GS, et al. Intravascular ultrasound classification of plaque distribution in left main coronary artery bifurcations: where is the plaque really located? Circ Cardiovasc Interv. 2010;3:105–112. 71. Džavík V, Colombo A. The absorb bioresorbable vascular scaffold in coronary bifurcations: insights from bench testing. JACC Cardiovasc Interv. 2014;7:81–88.

Percutaneous treatment of left main and non-left main bifurcation coronary lesions using drug-eluting stents.

Current evidence and guidelines support the use of the single-stent technique as the default treatment strategy for the treatment of coronary bifurcat...
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