Randomized study on simple versus complex stenting of coronary artery bifurcation lesions: the Nordic bifurcation study

Stenting of coronary bifurcation lesions: a literature and technical review

Newer generation drug-eluting stents have improved outcomes in various subsets of coronary lesions including bifurcation lesions. This article reviews the current literature on various issues in bifurcation percutaneous coronary intervention (PCI). Generally, the provisional approach of placing one stent in the main vessel is the preferred first-line treatment for most bifurcation lesions. However, some lesions require 2-stenting. It is unknown whether 2nd-generation DES have improved outcomes with 2-stenting. The use of fractional flow reserve (FFR) for the assessment of functional significance of the jailed side branch can help avoid unnecessary stenting in complex lesions. Skilled techniques in every step of the 2-stenting process and meticulous use of imaging techniques including IVUS or OCT are warranted to obtain optimal angiographic and clinical results. Dedicated bifurcation stents are feasible treatment options and may change future concepts in bifurcation PCI, although larger trials with control groups are required in order to widely apply these techniques into daily routine practice.

Approach to Treatment of Bifurcation Lesions

OPINION STATEMENT

Bifurcation lesions are frequently encountered in the cath lab [1] and remain a challenge for conventional percutaneous coronary intervention (PCI) techniques. Although provisional stenting remains the default approach for most bifurcation lesions [2-6], the two-stent technique is more appropriate in certain situations. If a two-stent strategy is selected, then final kissing balloon inflation (KBI) should be performed. Adjunctive assessment with intravascular imaging (intravascular ultrasound (IVUS)/optical coherence tomography (OCT)) and physiologic testing (fractional flow reserve, FFR) should be performed liberally. Drug-eluting stents (DES) are typically utilized to reduce the risk of restenosis in bifurcation disease.

Impact of side branch stenting on five-year long-term clinical outcome with the bifurcation-dedicated Axxess Biolimus A9-eluting stent system

AIMS

Our aim was to evaluate the five-year clinical impact of side branch (SB) stenting with a drug-eluting stent (DES) following Axxess stent implantation in coronary bifurcation lesions.

METHODS AND RESULTS

Four hundred patients treated with Axxess were pooled from the AXXESS Plus and DIVERGE five-year follow-up studies. We compared unadjusted and propensity-adjusted major adverse clinical events (MACE) between Axxess with no SB stenting ("Axxess provisional") versus Axxess with SB stenting ("Axxess additional"). "Axxess additional" had no impact on the MACE rate, with unadjusted and adjusted HR 1.59 (95% CI: 0.95-2.64) and 1.37 (95% CI: 0.88-2.13), respectively. No differences were seen in the individual components of death, myocardial infarction and ischaemia-driven target lesion revascularisation, respectively, both in unadjusted (HR 0.92 [95% CI: 0.38-2.19]; HR 1.73 [95% CI: 0.78-3.82]; HR 1.65 [95% CI: 0.84-3.26]) and adjusted analysis (HR 0.92 [95% CI: 0.41-2.09]; HR 1.13 [95% CI: 0.59-2.17]; HR 1.31 [95% CI: 0.74-2.31]). No differences in definite stent thrombosis were seen with unadjusted HR 2.1 (95% CI: 0.45-9.88) and adjusted HR 1.0 (95% CI: 0.32-3.1).

CONCLUSIONS

Stenting the SB following Axxess implantation does not impact on long-term clinical outcomes compared to MV stenting only. The Axxess stent system offers a safe and tailored alternative for the treatment of coronary bifurcation lesions.

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)

Most subordinate techniques accompanying bifurcation stenting have not been supported by relevant clinical trials. The aim of this study was to investigate the impact of technical specifications involved in bifurcation stenting on angiographic outcomes. We analyzed patients enrolled in a cohort consisting of the patients in 2 randomized studies: one comparing routine final kissing inflation (FKI) versus leave-alone strategy after the 1-stent technique for bifurcations without side branch (SB) stenosis (<50%) and the other comparing crush versus the 1-stent technique for lesions with SB stenosis (≥50%). The effects of subordinate techniques and devices on 8-month angiographic restenosis were studied using multivariate models. Of 514 patients whose 8-month angiograms were available, 58 (11.3%) were found to have restenosis involving, in total, 35 main branches (MBs) and 27 SBs. Using multivariate models, we identified FKI as the only independent predictor of MB restenosis in the technically modifiable variables. The effect of FKI was significantly different across subgroups defined by bifurcation lesion type and stenting technique (test for homogeneity, p = 0.003): FKI was unrelated to MB restenosis in the 1-stent for diseased SB (odds ratio [OR] 0.41, 95% confidence interval [CI] 0.10 to 1.72; p = 0.22) and the 2-stent groups (OR 0.14, 95% CI 0.01 to 1.36; p = 0.09) but predictive of MB restenosis in the 1-stent for normal SB group (OR 4.90, 95% CI 1.58 to 15.16; p = 0.006).

Effect of final kissing balloon dilatation after one-stent technique at left-main bifurcation: a single center data

Background:

Whether final kissing balloon (FKB) dilatation after one-stent implantation at left-main (LM) bifurcation site remains unclear. Therefore, this large sample and long-term follow-up study comparatively assessed the impact of FKB in patients with unprotected LM disease treated with one-stent strategy.

Methods:

Total 1528 consecutive patients underwent LM percutaneous coronary intervention in one center from January 2004 to December 2010 were enrolled; among them, 790 patients treated with one drug-eluting stent crossover LM to left anterior descending (LAD) with FKB (n = 230) or no FKB (n = 560) were comparatively analyzed. Primary outcome was the rate of major adverse cardiovascular events, defined as a composite of death, myocardial infarction (MI) and target vessel revascularization (TVR).

Results:

Overall, The prevalence of true bifurcation lesions, which included Medina classification (1,1,1), (1,0,1), or (0,1,1), was similar between-groups (non-FKB: 37.0% vs. FKB: 39.6%, P = 0.49). At mean 4 years follow-up, rates of major adverse cardiovascular events (non-FKB: 10.0% vs. FKB: 7.8%, P = 0.33), death, MI and TVR were not significantly different between-groups. In multivariate propensity-matched regression analysis, FKB was not an independent predictor of adverse outcomes.

Conclusions:

For patients treated with one-stent crossover LM to LAD, clinical outcomes appear similar between FKB and non-FKB strategy.

A Novel-Modified Provisional Bifurcation Stenting Technique: Jailed Semi-Inflated Balloon Technique

OBJECTIVE

We proposed a new technique for the treatment of coronary bifurcation lesions, called jailed semi-inflated balloon technique (JSBT).

BACKGROUND

Currently, provisional approach is recommended to treat most of coronary bifurcation lesions. However, it is associated with the risk of side branch (SB) occlusion after main vessel (MV) stenting due to plaque or carina shift into the SB. The SB occlusion may cause peri-procedural myonecrosis or hemodynamic compromise. Therefore, strategies are needed to reduce the SB occlusion during provisional approach.

METHODS

Between September 2014 and April 2015, we selected 137 patients (104 male, 33 female; mean age 63.6 ± 11.7 years) with 148 distinct coronary bifurcation lesions underwent percutaneous coronary intervention using JSBT. All patients were followed with hospital visits or telephone contact up to 1 month.

RESULTS

The majority of the patients had acute coronary syndrome (64.2%) and Medina 1.1.1. bifurcation lesions (62.8%). The lesion localization was distal left main (LM) coronary artery in 28 patients. After the MV stenting, thrombolysis in myocardial infarction (TIMI) 3 flow was established in 100% of both MV and SB. There was no SB occlusion in any patient. There was no major adverse cardiac event during in-hospital stay and 1 month follow-up.

CONCLUSIONS

The JSBT technique can be successfully performed in both LM and non-LM bifurcation lesion. This technique provides high rate of procedural success, excellent SB protection during MV stenting and excellent immediate clinical outcome.

Optimal kissing balloon inflation after single-stent deployment in a coronary bifurcation model

AIMS

To define the optimal kissing balloon inflation (KBI) after single-stent deployment in a coronary bifurcation model.

METHODS AND RESULTS

We deployed stents in main vessels (MV) followed by KBI in various conditions and compared the stent configurations. A) KBI at the operator's discretion vs. under the guidelines of minimal balloon overlapping (MBO). Various stent configurations were observed after the former option, whereas similar maximal dilation points were observed under the MBO guidelines. B) Long balloon overlapping (LBO) vs. MBO with proximal MV dilated by a large balloon. The proximal MV was dilated to an ideal round shape with MBO versus an oval shape with LBO. C) Two-link vs. 3-link stents. Although the 2-link stent was advantageous to open the side branch, it incurred a risk of overdilatation of the proximal struts, whereas the 3-link stent preserved its structure. Computed simulations of coronary flow were analysed in the following left main coronary models: circle with a diameter of 4 and 5.5 mm, ellipse with longitudinal direction and tilt position. They revealed that the overdilated side was exposed to low shear stress regardless of its shape.

CONCLUSIONS

Optimal KBI can be achieved with MBO and proximal dilatation by an optimally sized balloon.

Comparison of Angiographic Outcomes of Side Branch Ostium at Bifurcation Coronary Lesion between Two-stent and One-stent Techniques

Although the favored strategy for coronary bifurcation intervention is stenting main vessel with provisional side branch (SB) stenting, we occasionally use two-stent strategy. The objective of this study was to investigate the angiographic outcome of SB ostium in two-stent group, compared with one-stent group. We analyzed 199 patients with bifurcation lesion who underwent percutaneous coronary intervention (PCI) with drug-eluting stent and follow up angiography. The patients were divided into one-stent group (167 lesions, 158 patients) and two-stent group (41 lesions, 41 patients). Prior to intervention, SB ostium minimal luminal diameter (MLD) was smaller in two-stent group than in one-stent group (1.08±0.55 mm vs. 1.39±0.60 mm; P=0.01). But, immediately after PCI, SB MLD of two-stent group became greater than that of one-stent group (2.41±0.40 mm vs. 1.18±0.68 mm; P<0.01). Six to nine months after PCI, this angiographic superiority in SB MLD of two-stent group persisted (1.56±0.71 mm vs. 1.13±0.53 mm; P<0.01), although there was larger late loss in two-stent group (0.85±0.74 mm vs. 0.05±0.57 mm; P<0.01). In terms of target lesion revascularization and target vessel revascularization rates, one-stent group showed better results than two-stent group. We could attain wider long term SB ostium after two-stent strategy than after one-stent strategy.

When is a two-stent technique needed and which technique should then be used for bifurcation coronary lesions?

Although the guidelines recommend the provisional one-stent technique as a default technique for bifurcation coronary lesions, there are cases of bifurcations with large side branches (SB), difficult access and with ostial and diffuse disease extending more than 5 mm into the SB, where a two-stent strategy might be the best treatment option. Due to the inherent advantages and disadvantages of each two-stent technique, an appropriate technique should be selected according to each patient's clinical condition, bifurcation morphology and the operator's experience. Good long-term prognosis is most likely ensured by successful performance of each procedural step during the initial stenting.

Is there a need for dedicated devices?

Although the provisional approach is recommended over a systematic two-stent approach in bifurcation lesions, an a priori two-stent approach may be considered in certain specific anatomies in a minority of cases. Virtual bench test and intravascular imaging studies have provided essential insights into the technical aspects of bifurcation stenting and led to recommendations on how to optimise both the provisional and the two-stent strategies. Dedicated bifurcation stents may further optimise the procedural and clinical outcomes of both strategies. However, randomised data are sparse and more randomised trials are needed to provide evidence as to whether these dedicated devices will indeed improve procedural and clinical outcomes.

Randomized Comparison of FFR-Guided and Angiography-Guided Provisional Stenting of True Coronary Bifurcation Lesions: The DKCRUSH-VI Trial (Double Kissing Crush Versus Provisional Stenting Technique for Treatment of Coronary Bifurcation Lesions VI)

OBJECTIVES

This study sought to compare the outcomes of fractional flow reserve (FFR)-guided and angiography (Angio)-guided provisional side-branch (SB) stenting for true coronary bifurcation lesions.

BACKGROUND

Angio-guided provisional SB stenting after stenting of the main vessel provides favorable outcomes for the majority of coronary bifurcation lesions. Whether an FFR-guided provisional stenting approach is superior has not been studied.

METHODS

A total of 320 patients with single Medina 1,1,1 and 0,1,1 coronary bifurcation lesions undergoing stenting with a provisional SB approach were randomly assigned 1:1 to Angio-guided and FFR-guided groups. SB stenting was performed for Thrombolysis In Myocardial Infarction flow grade<3, ostial SB stenosis>70%, or greater than type A dissection after main vessel stenting in the Angio-guided group and for SB-FFR<0.80 in the FFR-guided group. The primary endpoint was the 1-year composite rate of major adverse cardiac events (cardiac death, myocardial infarction, and clinically driven target vessel revascularization).

RESULTS

Comparing the Angio-guided and FFR-guided groups, treatment of the SB (balloon or stenting) was performed in 63.1% and 56.3% of lesions respectively (p=0.07); stenting of the SB was attempted in 38.1% and 25.9%, respectively (p=0.01); and, when attempted, stenting was successful in 83.6% and 73.3% of SBs, respectively (p=0.01). The 1-year composite major adverse cardiac event rate was 18.1% in both groups (hazard ratio: 0.91, 95% confidence interval: 0.48 to 1.88; p=1.00). The 1-year target vessel revascularization and stent thrombosis rates were 6.9% and 5.6% (p=0.82) and 1.3% and 0.6% (p=0.56) in the Angio-guided and FFR-guided groups, respectively.

CONCLUSIONS

In this multicenter, randomized trial, angiographic and FFR guidance of provisional SB stenting of true coronary bifurcation lesions provided similar 1-year clinical outcomes. (Randomized Study on DK Crush Technique Versus Provisional Stenting Technique for Coronary Artery Bifurcation Lesions; ChiCTR-TRC-07000015).

Coronary bifurcation lesions: Present status and future perspectives

Coronary bifurcation lesions (CBLs) are challenging and associated with a higher rate of adverse events than non-bifurcation lesions. In the era of drug-eluting stents, 2 primary interventional strategies for treating CBL include the complex strategy the main vessel (MV) and side-branch (SB) stenting, and the simple strategy MV stenting combined with provisional SB stenting. The meta-analysis of the simple vs. complex strategies demonstrated an increased incidence of myocardial infarction in the complex strategy. Likewise, the Tryton dedicated bifurcation stents, as compared with the simple strategy, increased the rate of myocardial infarction. In contrast, the Nordic-Baltic Bifurcation Study IV demonstrated that event rates were not significantly different comparing the simple vs. complex strategies in true bifurcation lesions involving a large SB. Fractional flow reserve (FFR) has emerged as a powerful catheter based tool for the functional assessment of a stenosis, but the role of FFR on the long-term outcomes of patients with CBL has not been studied. Given the recent evidence that Tryton stents (a dedicated bifurcation stent) increased event rates, and the lack of benefit from using 2-stent techniques (the Nordic Baltic Bifurcation Study IV) in true CBL, assessing the FFR of the SB seems now of outmost importance, but randomized data are lacking. An intravascular study showed that kissing balloon inflation (KBI) significantly reduced SB stenosis, restored stent lumen at the carina, and expanded stent in the proximal segment. However, a recent randomized study showed no significant benefit of routine KBI. This review highlights current concepts and future perspectives in patients with CBL.

How bifurcation angle impacts the fate of side branch after main vessel stenting: a retrospective analysis of 1,200 consecutive bifurcation lesions in a single center

OBJECTIVES

We aimed to investigate the effect of bifurcation angle (BA) on side branch (SB) occlusion after main vessel (MV) stenting.

BACKGROUND

BA is thought to impact the risk of SB occlusion in coronary bifurcation patients undergoing percutaneous coronary intervention (PCI).

METHODS

A total of 1,171 consecutive patients with 1,200 bifurcation lesions undergoing one stent or provisional two stent techniques were studied. The lesions were divided into low angle and high angle groups using the median BA (52°). Multivariate logistic regression analysis was performed to identify independent predictors of SB occlusion.

RESULTS

SB occlusion occurred in 88 (7.33%) of 1,200 bifurcation lesions treated with the one stent technique or MV stenting first strategy. The rate of SB occlusion was significantly higher in the high angle group (63/600, 10.5%) than the low angle group (25/600, 4.2%) (P < 0.001). The rate of SB occlusion increased significantly across quartiles of BA as follows: from 3.63% in the first quartile of BA, to 4.71% in quartile II, to 8.14% in quartile III to 12.97% in quartile IV (P < 0.001). Multivariable analysis showed that high angle was an independent predictor of SB occlusion (odds ratio: 1.026, 95% confidence intervals: 1.014-1.037, P < 0.001). Plaque distribution at the same side of SB, MV Thrombolysis in Myocardial Infarction flow grade before stenting, pre-procedural diameter stenosis of bifurcation core, diameter ratio between MV/SB and diameter stenosis of SB before MV stenting were also independent predictors of SB occlusion.

CONCLUSIONS

High BA was an independent predictor of SB occlusion after MV stenting. The occlusion risk of SB with a high BA should not be ignored.

Intracoronary optical coherence tomography: a review of clinical applications

Optical coherence tomography (OCT) is a light-based technology that provides very high spatial resolution images. OCT has been initially employed as a research tool to investigate plaque morphology and stent strut coverage. The introduction of frequency domain OCT allowing fast image acquisition during a prolonged contrast injection via the guiding catheter has made OCT applicable for guidance of coronary interventions. In this manuscript, the various applications of OCT are reviewed, from assessment of plaque vulnerability and severity to characteristics of unstable lesions and thrombus burden to stent optimization and evaluation of late results.

Left main coronary artery disease: importance, diagnosis, assessment, and management

Left main coronary disease is seen in 4%-6% of patients undergoing coronary angiography for an ischemic evaluation and is a potentially fatal condition if not promptly identified and treated. Recent studies have increased our understanding of the complexity of left main coronary artery disease. This lesion subset offers numerous challenges in diagnosis and management. Fractional flow reserve and intravascular ultrasound are important adjuncts to angiography to determine the significance of ambiguous lesions of the left main coronary artery. Surgery is associated with much better outcomes than medical therapy and is considered by many to be the standard of care in patients who are surgical candidates. Recent studies comparing surgery with percutaneous coronary intervention (PCI) have defined subgroups with lesser extent of disease burden that may do just as well with PCI. Challenges remain in the management of bifurcation disease, and the interventional community anxiously awaits the results of the large-scale randomized trials comparing PCI with surgery.

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

Final kissing-balloon inflation is often recommended for percutaneous coronary intervention (PCI) of bifurcation lesions. However, randomized trials focusing on kissing inflation have not confirmed its beneficial impact. We compared outcomes of kissing inflation for PCI of bifurcation lesions, explicitly stratifying results according to stenting strategy. Patients undergoing bifurcation PCI were retrospectively enrolled. Subjects receiving final kissing inflation were compared with those not undergoing kissing inflation, after stratification for a single-stent technique. The primary end point was the long-term rate of major adverse cardiac events (MACE, i.e., death, myocardial infarction, or target lesion revascularization (TLR)). A total of 4314 patients were included: 1176 (27.3 %) treated with a single stent and kissing inflation, 1637 (37.9 %) with a single stent but no kissing, 1072 (24.8 %) with two stents and kissing, and 429 (9.9 %) with two stents but no kissing. At unadjusted analyses kissing was associated with fewer short-term MACE and deaths in the two-stent group, and with fewer long-term MACE, cardiac deaths, and side-branch TLR in the two-stent group (all P < 0.05). Conversely, kissing appeared detrimental after single stenting. However, after multivariable analyses, kissing no longer significantly affected the risk of adverse events, with the exception of the risk of side-branch TLR, which was lower in those receiving two stents and final kissing inflation (hazard ratio = 0.52, 95 % confidence interval 0.30–0.90, P = 0.020). Kissing inflation can be avoided in bifurcation lesions uneventfully treated with single-stent PCI. However, final kissing-balloon inflation appears beneficial in reducing the risk of side-branch repeat revascularization after using a two-stent strategy.

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)

OBJECTIVES

The present study established criteria to differentiate simple from complex bifurcation lesions and compared 1-year outcomes stratified by lesion complexity after provisional stenting (PS) and 2-stent techniques using drug-eluting stents.

BACKGROUND

Currently, no criterion can distinguish between simple and complex coronary bifurcation lesions. Comparisons of PS and 2-stent strategies stratified by lesion complexity have also not been reported previously.

METHODS

Criteria of bifurcation complexity in 1,500 patients were externally tested in another 3,660 true bifurcation lesions after placement of drug-eluting stents. The primary endpoint was the occurrence of a major adverse cardiac event (MACE) at 12 months. The secondary endpoint was the rate of stent thrombosis (ST).

RESULTS

Complex (n = 1,108) bifurcation lesions were associated with a higher 1-year rate of MACE (16.8%) compared with simple (n = 2,552) bifurcation lesions (8.9%) (p < 0.001). The in-hospital ST and 1-year target lesion revascularization rates after 2-stent techniques in the simple group (1.0% and 5.6%, respectively) were significantly different from those after PS (0.2% [p = 0.007] and 3.2% [p = 0.009], respectively); however, 1-year MACE rates were not significantly different between the 2 groups. For complex bifurcation lesions, 2-stent techniques had lower rates of 1-year cardiac death (2.8%) and in-hospital MACE (5.0%) compared with PS (5.3%, p = 0.047; 8.4%, p = 0.031).

CONCLUSIONS

Complex bifurcation lesions had higher rates of 1-year MACE and ST. The 2-stent and PS techniques were overall equivalent in 1-year MACE. However, 2-stent techniques for complex lesions elicited a lower rate of cardiac death and in-hospital MACE but higher rates of in-hospital ST and revascularization at 1 year for simple lesions.

The utility of stent enhancement to guide percutaneous coronary intervention for bifurcation lesions

AIMS

Percutaneous coronary intervention (PCI) of bifurcation lesions is complex and is technically very demanding. Coronary angiography is considered the gold standard method to guide PCI but has several limitations. The purpose of this study was to determine the utility of stent enhancement with StentBoost® (StB), a novel fluoroscopic imaging technique, and its potential role during bifurcation PCI.

METHODS AND RESULTS

This prospective study included 97 patients who underwent bifurcation PCI (98 bifurcations), using StB. Bifurcation lesions were classified according to the modified Medina classification. StB was performed in all patients to obtain improved stent visualisation and to detect optimal release and deployment. Therefore, three groups were formed, according to the quality of image: optimal visualisation, suboptimal visualisation and poor visualisation. Most of the bifurcation disease involved the main vessel (99%) and in 80 patients (81.6%) there was side branch involvement. Most bifurcations had both main vessel and side branch lesions (Medina 1,1,1) (70 patients, 71.4%). StB image quality was good in 79.6% of the cases (optimal visualisation of the stent and guidewire), was suboptimal in 19.4%, and poor in 1% (overlapping of structures or devices). In three cases, StB enabled the identification of the guidewire and angioplasty balloon passing outside stent borders during rewiring of the side branch.

CONCLUSIONS

Imaging techniques have a primary role during bifurcation PCI. StentBoost is a simple and quick method that offers several advantages, enabling improved stent visualisation, appropriate rewiring of the side branch, adequate stent expansion and optimal apposition of the struts to the wall.