Impact of 3-Dimensional Bifurcation Angle on 5-Year Outcome of Patients After Percutaneous Coronary Intervention for Left Main Coronary Artery Disease

Definitions and Standardized Endpoints for Treatment of Coronary Bifurcations

The Bifurcation Academic Research Consortium (Bif-ARC) project originated from the need to overcome the paucity of standardization and comparability between studies involving bifurcation coronary lesions. This document is the result of a collaborative effort between academic research organizations and the most renowned interventional cardiology societies focused on bifurcation lesions in Europe, the United States, and Asia. This consensus provides standardized definitions for bifurcation lesions; the criteria to judge the side branch relevance; the procedural, mechanistic, and clinical endpoints for every type of bifurcation study; and the follow-up methods. Considering the complexity of bifurcation lesions and their evaluation, detailed instructions and technical aspects for site and core laboratory analysis of bifurcation lesions are also reported. The recommendations included within this consensus will facilitate pooled analyses and the effective comparison of data in the future, improving the clinical relevance of trials in bifurcation lesions, and the quality of care in this subset of patients.

High triglyceride-glucose index predicts cardiovascular events in patients with coronary bifurcation lesions: a large-scale cohort study

BACKGROUND

Coronary bifurcation lesion, as a complex coronary lesion, is associated with higher risk of long-term poor prognosis than non-bifurcation lesions. The triglyceride-glucose (TyG) index has been shown to predict cardiovascular (CV) events in patients with coronary artery disease (CAD). However, the prognostic value of the TyG index in patients with bifurcation lesions who are at high risk of CV events remains undetermined. Therefore, this study aimed to investigate the association between the TyG index and CV events in patients with bifurcation lesions.

METHODS

A total of 4530 consecutive patients with angiography-proven CAD and bifurcation lesions were included in this study from January 2017 to December 2018. The TyG index was calculated as Ln [fasting triglyceride (mg/dL) × fasting plasma glucose (mg/dL)/2]. Patients were assigned into 3 groups according to TyG tertiles (T) (T1: <8.633; T2: 8.633-9.096 and T3: ≥9.096). The primary endpoint was CV events, including CV death, nonfatal myocardial infarction and nonfatal stroke at 3-year follow-up. Restricted cubic spline (RCS) analysis, Kaplan-Meier curves and Cox proportional hazard models were used to investigate the associations between the TyG index and study endpoints.

RESULTS

During a median follow-up of 3.1 years, 141 (3.1%) CV events occurred. RCS analysis demonstrated a linear relationship between the TyG index and events after adjusting for age and male sex (non-linear P = 0.262). After multivariable adjustments, elevated TyG index (both T2 and T3) was significantly associated with the risk of CV events (hazard ratio [HR], 1.68; 95% confidence interval [CI],1.06-2.65; HR, 2.10; 95%CI, 1.28-3.47, respectively). When study patients were further stratified according to glycemic status, higher TyG index was associated with significantly higher risk of CV events in diabetic patients after adjusting for confounding factors (T3 vs. T1; HR, 2.68; 95%CI, 1.17-6.11). In addition, subgroup analysis revealed consistent associations of the TyG index with 3-year CV events across various subgroups. Furthermore, adding the TyG index to the original model significantly improved the predictive performance.

CONCLUSIONS

High TyG index was associated with CV events in patients with bifurcation lesions, suggesting the TyG index could help in risk stratification and prognosis in this population.

Impact of coronary bifurcation angle on stent malapposition in a randomized comparison between proximal optimization technique followed by side branch dilatation and kissing balloon inflation

Background

The impact of coronary bifurcation angle (BA) on incomplete stent apposition (ISA) after crossover stenting followed by side branch (SB) intervention has not been established.

Methods

A total of 100 crossover stentings randomly treated with proximal optimization technique followed by short balloon dilation in the SB (POT-SBD group, 48 patients) and final kissing balloon technique (KBT group, 52 patients) were analyzed in the PROPOT trial. Major ISA with maximum distance > 400 μm and its location was determined using optical coherence tomography before SB intervention and at the final procedure. The BA was defined as the angle between the distal main vessel and SB. Optimal POT was determined when the difference in stent volume index between the proximal and distal bifurcation was greater than the median value (0.86 mm3/mm) before SB intervention.

Result

Major ISA was more frequently observed in the POT-SBD than in the KBT group (35% versus 17%, p < 0.05). In the POT-SBD group, worsening ISA after SBD was prominent at the distal bifurcation. The BA was an independent predictor of major ISA (odds ratio 1.04, 95% confidence interval 1.00-1.07, p < 0.05) with a cut-off value of 59.5° (p < 0.05). However, the cases treated with optimal POT in the short BA (<60°) indicated the lowest incidence of major ISA. In the KBT group, BA had no significant impact.

Conclusion

A wide BA has a potential risk for the occurrence of major ISA after POT followed by SBD in coronary bifurcation stenting.

Dynamic assessment of the left main-left circumflex bending angle: Implications for ostial left circumflex artery in-stent restenosis after successful two-stent PCI

BACKGROUND

Two-stent techniques for percutaneous coronary intervention (PCI) on left main (LM) bifurcation (LMB) lesions are associated with an increased risk of in-stent restenosis (ISR) at left circumflex artery (LCx) ostium but the underlying mechanisms are incompletely understood. This study sought to investigate the association between cyclic change of LM-LCx bending angle (BA_LM-LCx) and the risk of ostial LCx ISR following two-stent techniques.

METHODS

In a retrospective cohort of patients undergoing two-stent PCI for LMB lesions, BA_LM-LCx and distal bifurcation angle (DBA) were computed with 3-dimensional angiographic reconstruction. The analysis was performed both at end-diastole and end-systole, and the angulation change throughout the cardiac cycle was defined as the cardiac motion-induced angulation change (∆_CAngle).

RESULTS

A total of 101 patients were included. The mean pre-procedural BA_LM-LCx was 66.8 ± 16.1° at end-diastole and 54.1 ± 13.3° at end-systole with a range of 13.0 ± 7.7°. Pre-procedural ∆_CBA_LM-LCx > 16.4° was the most relevant predictor of ostial LCx ISR (adjusted OR 11.58, 95% CI 4.04-33.19; p < 0.001). Post-procedural ∆_CBA_LM-LCx > 9.8° and stent-induced diastolic BA_LM-LCx change > 11.6° were also related with ostial LCx ISR. DBA was positively correlated with BA_LM-LCx and showed a weaker association of pre-procedural ∆_CDBA > 14.5° with ostial LCx ISR (adjusted OR 6.87, 95% CI 2.57-18.37; p < 0.001).

CONCLUSIONS

Three-dimensional angiographic bending angle is a feasible and reproducible novel method for LMB angulation measurement. A large pre-procedural cyclic change of BA_LM-LCx was associated with an increased risk of ostial LCx ISR following two-stent techniques.

Trends in the cost-effectiveness level of percutaneous coronary intervention: Macro socioeconomic analysis and health technology assessment

Percutaneous coronary intervention (PCI), one of the most prevalent techniques of revascularization, is a procedure that remarkably improves treatment outcomes. However, it consumes large amounts of medical resources and has resulted in an increased socioeconomic burden due to the increasing number of target patients. In recent years, there have been sporadic discussions, both in Japan and other countries, regarding the optimization of interventions and the perspective of medical economics. Based on this, previous studies on PCI-related cost-effectiveness were reviewed in order to consider the current level of medical economics regarding PCI. Using the databases MEDLINE and EMBASE, a survey involving data from original articles and systematic reviews was conducted from January 2010 to August 2022. Conditions were not imposed on the evidence level due to the paucity of studies, although field studies were prioritized over simulation studies. The macro medical economics of acute myocardial infarction treatment, which is the primary target of PCI, were generally at an average level when compared to those in other countries; however, there is room for further improvement in Japan's performance. Revascularization in a population with multivessel coronary artery disease showed that coronary artery bypass graft surgery tended to be more cost-effective than PCI in the long-term setting. However, it was suggested that PCI may be more cost-effective in patients with SYNTAX Score ≤22 or left main artery disease. A cost-effectiveness report for stable angina patients was not in favor of PCI over medical therapy. Moreover, there were some reports showing the medical economic superiority of early myocardial ischemia evaluation, and it was foreseen that active selection of patients will contribute to the improvement of the overall cost-effectiveness of PCI. In order to further improve the socioeconomic significance of PCI in the future, it is necessary to aim for harmony between clinical practice and health economics.

Impact of coronary bifurcation angle on the pathogenesis of atherosclerosis and clinical outcome of coronary bifurcation intervention–A scoping review

Background

A coronary bifurcation stenting is still a challenging issue due to frequent restenosis and stent thrombosis even with drug-eluting stents. The bifurcation angle (BA) between a main vessel and a side branch is one of the crucial determinants of coronary flow and shear stress that affect the plaque distribution. Previous bench and clinical studies have evaluated the impact of the BA between the proximal main vessel and the side branch (Angle A) and the BA between the distal main vessel and the side branch (Angle B) on the clinical outcomes of bifurcation stenting. However, the impact has not yet been fully elucidated due to a lack of statistical power or different manner of the assessment of BA.

Objectives

To analyze the published studies on coronary artery BA, the modalities used for assessment, and the impact of BA on interventions and attempt to define the pre-procedural protocols.

Data sources

A scoping review was performed using the Joanna Briggs Institute Methodology. A total of 52 relevant references were selected from PubMed, Cochrane Library, and CINAHL databases and categorized into three topic areas.

Results and conclusions

A wider Angle A is associated with the increased likelihood of carina shift and a wider Angle B, with that of side branch occlusion. A wider Angle B promotes stent malapposition and deformation in the side branch ostium and has been reported as an independent predictor of major adverse cardiac events after bifurcation stenting; however, improvement of the drug-eluting stent, refinement of the stenting technique, and accurate 3-dimensional assessment may attenuate the adverse clinical impact of a wider BA.

Implications of key findings

Assessment of the BA is necessary to predict the effect of bifurcation intervention procedure on the stent configuration and coronary flow at the bifurcated vessels. This will help to optimize stent selection and the stenting technique.

Definitions and Standardized Endpoints for Treatment of Coronary Bifurcations

The Bifurcation Academic Research Consortium (Bif-ARC) project originated from the need to overcome the paucity of standardization and comparability between studies involving bifurcation coronary lesions. This document is the result of a collaborative effort between academic research organizations and the most renowned interventional cardiology societies focused on bifurcation lesions in Europe, the United States, and Asia. This consensus provides standardized definitions for bifurcation lesions; the criteria to judge the side branch relevance; the procedural, mechanistic, and clinical endpoints for every type of bifurcation study; and the follow-up methods. Considering the complexity of bifurcation lesions and their evaluation, detailed instructions and technical aspects for site and core laboratory analysis of bifurcation lesions are also reported. The recommendations included within this consensus will facilitate pooled analyses and the effective comparison of data in the future, improving the clinical relevance of trials in bifurcation lesions, and the quality of care in this subset of patients.

Predicted and Observed Mortality at 10 Years in Patients With Bifurcation Lesions in the SYNTAX Trial

BACKGROUND

Percutaneous coronary intervention (PCI) of bifurcation lesions is associated with higher rates of adverse events, and currently it is unclear whether PCI or coronary artery bypass grafting (CABG) is the safer treatment for these patients at very long-term follow-up.

OBJECTIVES

The aim of this study was to investigate the impact of bifurcation lesions on individual predicted and observed all-cause 10-year mortality in the SYNTAX (Synergy Between PCI With Taxus and Cardiac Surgery) trial.

METHODS

In the SYNTAXES (SYNTAX Extended Survival) study, 10-year observed and individual predicted mortality derived from the SYNTAX score 2020 (SS-2020) was compared between patients with ≥1 bifurcation (n = 1,300) and those with no bifurcations (n = 487).

RESULTS

Among patients treated with PCI, patients with >1 bifurcation lesion compared with those without bifurcation lesions had a significantly higher risk for all-cause death (19.8% vs 30.1%; HR: 1.55; 95% CI: 1.12-2.14; P = 0.007), whereas following CABG, mortality was similar in patients with and those without bifurcation lesions (23.3% vs 23.0%; HR: 0.81; 95% CI: 0.59-1.12; P = 0.207; P_interaction = 0.006). In PCI patients, a 2-stent vs a 1-stent technique was associated with higher mortality (33.3% vs 25.9%; HR: 1.51; 95% CI: 1.06-2.14; P = 0.021). According to the SS-2020, among those with ≥1 bifurcation, there was equipoise for all-cause mortality between PCI and CABG in 2 quartiles of the population, whereas CABG was superior to PCI in the 2 remaining quartiles.

CONCLUSIONS

Bifurcation lesions require special attention from the heart team, considering the higher 10-year all-cause mortality associated with PCI. Careful evaluation of bifurcation lesion complexity and calculation of individualized 10-year prognosis using the SS-2020 may therefore be helpful in decision making. (Synergy Between PCI With TAXUS and Cardiac Surgery: SYNTAX Extended Survival [SYNTAXES], NCT03417050; Taxus Drug-Eluting Stent Versus Coronary Artery Bypass Surgery for the Treatment of Narrowed Arteries [SYNTAX], NCT00114972).

Polymer Coating Integrity, Thrombogenicity and Computational Fluid Dynamics Analysis of Provisional Stenting Technique in the Left Main Bifurcation Setting: Insights from an In-Vitro Model

Currently, the provisional stenting technique is the gold standard in revascularization of lesions located in the left main (LM) bifurcation. The benefit of the routine kissing balloon technique (KBI) in bifurcation lesions is still debated, particularly following the single stent treatment. We compared the latest-generation drug-eluting stent (DES) with no side branch (SB) dilatation “keep it open” technique (KIO) vs. KBI technique vs. bifurcation dedicated drug-eluting stent (BD-DES) implantation. In vitro testing was performed under a static condition in bifurcation silicone vessel models. All the devices were implanted in accordance with the manufacturers’ recommendations. As a result, computational fluid dynamics (CFD) analysis demonstrated a statistically higher area of high shear rate in the KIO group when compared to KBI. Likewise, the maximal shear rate was higher in number in the KIO group. Floating strut count based on the OCT imaging was significantly higher in KIO than in KBI and BD-DES. Furthermore, according to OTC analysis, the thrombus area was numerically higher in both KIO and KBI than in the BD-DES. Scanning electron microscopy (SEM) analysis shows the highest degree of strut coating damage in the KBI group. This model demonstrated significant differences in CFD analysis at SB ostia with and without KBI optimization in the LM setting. The adoption of KBI was related to a meaningful reduction of flow disturbances in conventional DES and achieved results similar to BD-DES.

One-year Outcome of Different Unprotected Left Main Percutaneous Coronary Interventions Techniques in Acute Coronary Syndromes

Background: We intended in this study to evaluate the impact of the different techniques of unprotected left main coronary artery (ULMCA) stenting on the clinical outcomes. Methods: The study included 65 patients with ACS and left main disease subjected to UPLMCA intervention [46 males (70.8%) with median(Q1-Q3) age of 63(53-70) years old] in an observational prospective cohort study. Data were collected through reviewing patient’s medical records and angiographic procedures. Angiographic assessment included evaluation of Syntax II score, EURO II score, and TIMI flow grading. The primary outcome was the major adverse cardiac and cerebral events (MACCE) at 1 year while the secondary outcomes included the development of acute kidney injury (AKI), one year mortality, and need for CABG post PCI. Results: One-year MACCE was 46.2 % when the angle between LAD and LCX was>70o compared to 81.5% when it was less than 70o (P=0.008). The wide angle was also associated with 0% 1-year mortality compared to 18.5% for narrow angle, a difference which is statistically significant (P=0.03). The 1-year MACCE was 35.7% compared to 74.4% when it was not used (P=0.013). When POT was used, the 1-year MACCE was 47.6% compared to 75% when it was not used (P=0.041). None of the other studied parameters including those related to procedure technique was significantly affecting the outcome in our study. Conclusion: We concluded that the non-use of FKI nor POT together with the lower angulation between LAD and LCX could predict worse clinical outcome at one-year in unprotected left main PCI.

Clinical impact of bifurcation angle change between diastole and systole in complex stenting for left main distal bifurcation: The Milan and New-Tokyo (MITO) Registry

OBJECTIVES

We assessed the impact of pre-percutaneous coronary intervention (PCI) bifurcation angle change (BAC) on clinical outcomes.

BACKGROUND

There are little available data about the impact of BAC in unprotected left main distal bifurcation lesions (ULMD) PCI.

METHODS

We identified consecutive 300 patients with ULMD underwent complex stenting using drug-eluting stent in three high-volume centers (Tokyo and Milan). We measured the widest BA of ULMD at both end-diastole and end-systole before stenting with two-dimensional quantitative coronary angiographic assessment and calculated the BAC value as a difference of two BA value in each lesion. We divided them into small and large BAC group according to the median BAC value (7.2°). The primary endpoint was target lesion failure (TLF), which was defined as a composite of cardiac death, target lesion revascularization (TLR) and myocardial infarction.

RESULTS

TLF rate at 3-year was significantly higher in the large BAC group than in the small BAC group (adjusted hazard ratio [HR] 5.85; 95% confidence interval [CI], 3.40-10.1; p < .001). TLR rate for left main (LM) to left anterior descending artery (LAD) and ostial left circumflex artery (LCXos) at 3-year were significantly higher in large BAC group than in small BAC group (adjusted HR 5.91; 95% CI, 2.03-17.2; p = .001 and adjusted HR 10.6; 95% CI, 5.20-21.6; p < .001, respectively).

CONCLUSIONS

A large BAC before stenting is strongly associated with adverse events after complex stenting for ULMD, mainly driven by repeat PCI for restenosis of the LCXos and of the LM-LAD.

Angiography-Based 4-Dimensional Superficial Wall Strain and Stress: A New Diagnostic Tool in the Catheterization Laboratory

A novel method for four-dimensional superficial wall strain and stress (4D-SWS) is derived from the arterial motion as pictured by invasive coronary angiography. Compared with the conventional finite element analysis of cardiovascular biomechanics using the estimated pulsatile pressure, the 4D-SWS approach can calculate the dynamic mechanical state of the superficial wall in vivo, which could be directly linked with plaque rupture or stent fracture. The validation of this approach using in silico models showed that the distribution and maximum values of superficial wall stress were similar to those calculated by conventional finite element analysis. The in vivo deformation was validated on 16 coronary arteries, from the comparison of centerlines predicted by the 4D-SWS approach against the actual centerlines reconstructed from angiograms at a randomly selected time-point, which demonstrated a good agreement of the centerline morphology between both approaches (scaling: 0.995 ± 0.018 and dissimilarity: 0.007 ± 0.014). The in silico vessel models with softer plaque and larger plaque burden presented more variation in mean lumen diameter and resulted in higher superficial wall stress. In more than half of the patients (n = 16), the maximum superficial wall stress was found at the proximal lesion shoulder. Additionally, in three patients who later suffered from acute coronary syndrome, the culprit plaque rupture sites co-localized with the site of highest superficial wall stress on their baseline angiography. These representative cases suggest that angiography-based superficial wall dynamics have the potential to identify coronary segments at high-risk of plaque rupture and fracture sites of implanted stents. Ongoing studies are focusing on identifying weak spots in coronary bypass grafts, and on exploring the biomechanical mechanisms of coronary arterial remodeling and aneurysm formation. Future developments involve integration of fast computational techniques to allow online availability of superficial wall strain and stress in the catheterization laboratory.

Fallacies and Possible Remedies of the SYNTAX Score

Quite a few studies have revealed the clinical values regarding the outcome predictions in the cohort of the Synergy between Percutaneous Coronary Intervention with Taxus and Cardiac Surgery (SYNTAX) trial and decision-making with the SYNTAX score. The Evaluation of Xience Everolimus-Eluting Stent Versus Coronary Artery Bypass Surgery for Effectiveness of Left-Main Revascularization (EXCEL) and Nordic-Baltic-British left main revascularization (NOBLE) studies are the largest international randomized studies so far, comparing percutaneous coronary intervention (PCI) and coronary artery bypass graft (CABG) in the treatment of left main coronary artery disease. Unfortunately, both studies failed to validate the value of the SYNTAX score in the selection of revascularization strategies for patients with coronary artery diseases (CAD).. This scenario prompted us to reconsider the inherent fallacies of the SYNTAX score in its derivation. We pointed out eight fallacies for the SYNTAX score in this paper. A recently developed Coronary Artery Tree description and Lesion EvaluaTion (CatLet) score, available at http://www.catletscore.com, a novel angiographic scoring system, could be the remedies for the SYNTAX score.

Comparison of overexpansion capabilities and thrombogenicity at the side branch ostia after implantation of four different drug eluting stents

Interventions in bifurcation lesions often requires aggressive overexpansion of stent diameter in the setting of long tapering vessel segment. Overhanging struts in front of the side branch (SB) ostium are thought to act as a focal point for thrombi formation and consequently possible stent thrombosis. This study aimed to evaluate the overexpansion capabilities and thrombogenicity at the SB ostia after implantation of four latest generation drug-eluting stents (DES) in an in-vitro bifurcation model. Four clinically available modern DES were utilized: one bifurcation dedicated DES (Bioss LIM C) and three conventional DES (Ultimaster, Xience Sierra, Biomime). All devices were implanted in bifurcation models with proximal optimization ensuring expansion before perfusing with porcine blood. Optical coherence tomography (OCT), immunofluorescence (IF) and scanning electron microscope analysis were done to determine thrombogenicity and polymer coating integrity at the over-expanded part of the stents. Computational fluid dynamics (CFD) was performed to study the flow disruption. OCT (p = 0.113) and IF analysis (p = 0.007) demonstrated lowest thrombus area at SB ostia in bifurcation dedicated DES with favorable biomechanical properties compared to conventional DES. The bifurcated DES also resulted in reduced area of high shear rate and maximum shear rate in the CFD analysis. This study demonstrated numerical differences in terms of mechanical properties and acute thrombogenicity at SB ostia between tested devices.

Treatment with a dedicated bifurcation sirolimus-eluting cobalt-chromium stent for distal left main coronary artery disease: rationale and design of the POLBOS LM study

AIMS

The aim of this study is to demonstrate the non-inferiority of the BiOSS LIM C sirolimus-eluting cobalt-chromium bifurcation dedicated stent against the XIENCE stent regarding the patient-oriented composite endpoint (POCE) at 12 months among patients with left main coronary artery disease (LMCA).

METHODS AND RESULTS

The POLBOS LM study is a single-arm, prospective, multicentre study enrolling 260 patients (SYNTAX score ≤32) with a pre-specified performance goal based on the results of the EXCEL trial with contemporary percutaneous coronary intervention (PCI) for LMCA disease. Patient enrolment will comply with objective inclusion criteria of diameter stenosis ≥50% in the LMCA based on off-line quantitative coronary angiography (QCA) analysed by an independent core laboratory using dedicated bifurcation QCA software. The BiOSS LIM C is used for the treatment of LMCA disease with the same specific technical classification as for the BiOSS LIM (modified MADS classification) and the stent implantation is optimised by using pre-specified intravascular ultrasound criteria. The primary endpoint is POCE (a composite of all-cause death, stroke, any myocardial infarction, and any revascularisation) at 12 months.

CONCLUSIONS

The POLBOS LM study will indicate the efficacy of the BiOSS LIM C stent with contemporary PCI for distal left main bifurcation lesions in comparison with the XIENCE stent from the recent EXCEL trial, as a performance index.

Clinical Implications of Bifurcation Angles in Left Main Bifurcation Intervention Using a Two-Stent Technique

Objectives

The aim of this study was to assess the clinical impact of 3 bifurcation angles in left main (LM) bifurcation treated with the 2-stent technique.

Background

Data are limited regarding the impact of bifurcation angles after LM percutaneous coronary intervention (PCI).

Methods

Using patient-level 4 multicenter registries in Korea, 462 patients undergoing LM bifurcation PCI with the 2-stent technique were identified (181 crush, 167 T-stenting; 63% 1^st generation drug-eluting stent (DES), 37% 2^nd generation DES). Three bifurcation angles, between the LM and left anterior descending (LAD), the LM and left circumflex (LCX), and the LAD and LCX, were measured. The primary outcome was target lesion failure (TLF), a composite of cardiac death, myocardial infarction, and target lesion revascularization (TLR).

Results

In patients treated with the crush technique, the best cutoff value (BCV) to predict TLF was 152° of the LM-LAD angle. In the crush group, a significantly higher TLF rate, mostly driven by TLR, was observed in the LM-LAD angle ≥152° group compared with the <152° group (35.7% vs. 14.6%; adjusted hazard ratio 3.476; 95% confidence interval 1.612–7.492). An LM-LAD angle ≥152° was an independent predictor of TLF. In the T-stenting, no bifurcation angle affected the clinical outcomes.

Conclusions

In LM bifurcation PCI using the 2-stent technique, wide LM-LAD angle (≥152°) was associated with a greater risk of TLF in the crush, whereas none of the bifurcation angles affected T-stenting outcomes.

[Left main PCI: Current treatment]

Percutaneous coronary intervention (PCI) of left main coronary artery has become a strong alternative to coronary artery bypass surgery in selected patients. The treatment decision must be validated by the Heart Team. Several PCI techniques of distal left main PCI have been described but the KISSS (Keep it simple, swift and safe) principle recommended by the European Bifurcation Club must be kept in mind. Provisional stenting is the first-line technique. A two-stent strategy may be needed in the presence of≥2.5mm side branch diameter and significant ostial stenosis as well as in presumably difficult rewiring. In all cases, POT (Proximal Optimisation Technique) is mandatory. Intracoronary imaging can be of great help in perfecting the result or even to improve outcomes.

Left main coronary artery disease: pathophysiology, diagnosis, and treatment

The advent of coronary angiography in the 1960s allowed for the risk stratification of patients with stable angina. Patients with unprotected left main coronary artery disease have an increased risk of death related to the large amount of myocardium supplied by this vessel. Although coronary angiography remains the preferred imaging modality for the evaluation of left main coronary artery stenosis, this technique has important limitations. Angiograms of the left main coronary artery segment can be difficult to interpret, and almost one-third of patients can be misclassified when fractional flow reserve is used as the reference. In patients with clinically significant unprotected left main coronary artery disease, surgical revascularization was shown to improve survival compared with medical therapy and has been regarded as the treatment of choice for unprotected left main coronary artery disease. Two large-scale clinical trials published in 2016 support the usefulness of catheter-based revascularization in selected patients with unprotected left main coronary artery disease. In this Review, we describe the pathophysiology of unprotected left main coronary artery disease, discuss diagnostic approaches in light of new noninvasive and invasive imaging techniques, and detail risk stratification models to aid the Heart Team in the decision-making process for determining the best revascularization strategy for these patients.

Technical Approaches to Left Main Coronary Intervention: Contemporary Best Practices

Left main percutaneous coronary intervention is an acceptable alternative to coronary artery bypass grafting, and in experienced hands, excellent procedural results can be obtained. A systematic approach to stenting and meticulous attention to detail are required. For most lesions, a single-stent provisional approach is sufficient, but for the more complex lesion, a 2-stent technique is required. Herein, the optimal approach to left main lesion assessment and percutaneous intervention is described.

A randomized trial comparing two stent sizing strategies in coronary bifurcation treatment with bioresorbable vascular scaffolds - The Absorb Bifurcation Coronary (ABC) trial

BACKGROUND

Limited information is available on the use of Bioresorbable Vascular Scaffold (BVS) in bifurcations involving significant side branches. When treating bifurcation disease with metal stents, the recommendation is to choose a stent diameter based on the distal main vessel diameter. Whether this sizing strategy is applicable to BVS is currently unknown.

METHODS

We randomised 37 patients undergoing elective PCI for 'false' bifurcation disease (Medina 0,1,0; 1,0,0; 1,1,0) to receive BVS based either on proximal or distal reference diameters. Optical Frequency Domain Imaging (OFDI) measurements were performed pre BVS insertion to obtain proximal and distal reference diameters and post implantation. BVS size was chosen according to the proximal or distal reference diameter as per randomisation. Implantation was performed using the PSP technique tailored to bifurcation stenting. OFDI was repeated post implantation to confirm satisfactory expansion and apposition.

RESULTS

Baseline demographics between the two groups were similar. Patients were aged 62.8 ± 3.3 years; 76% were male. Mean side branch diameter was 2.24 ± 0.13 mm. TIMI III flow in the main vessel was achieved in all cases. Side branch occlusion occurred in 1 case (2.7%). In the distal-sizing arm, there was a greater incidence of significant malapposition (>300 μm) at the proximal end of the scaffold on OCT (2.3% versus 0.8%, p 0.023). The incidence of distal edge dissections was numerically greater in the proximal-sizing group but this was not statistically significant (31.3% vs 11.8%, p 0.17).

CONCLUSION

Both proximal and distal sizing strategies have similar procedural complication rates when using the ABSORB BVS to treat coronary bifurcations. However a proximal sizing strategy is associated with less malapposition and may be preferable.

State of the art: coronary angiography

In the early days of coronary angiography, the precise quantification of luminal narrowing was challenging. The introduction of balloon angioplasty (percutaneous transluminal coronary angioplasty [PTCA]) by Andreas Grüntzig in 1977 was perhaps the greatest incentive to the development of quantitative coronary angiography (QCA). QCA has played a crucial role in evaluating interventional techniques and assessing the results of new technologies. With the advent of drug-eluting stents (DES), QCA metrics such as late lumen loss and diameter stenosis (restenosis) proved to be instrumental in assessing new technologies. Refinements in QCA with the advent of dedicated bifurcation analysis and three-dimensional (3D) QCA have broadened the application of QCA. Beyond angiographic metrics, new developments in the field of QCA have introduced the functional component in the assessment of coronary lesions. Angiography-derived fractional flow reserve (FFR) may be a good tool for diagnosing ischaemia-producing lesions in patients with non-complex coronary artery disease. Furthermore, the incremental functional information can be used to expand the traditional late lumen loss (LLL) and restenosis concepts.

Relationship between left main and left anterior descending arteries bifurcation angle and coronary artery calcium score in chronic kidney disease: A 3-dimensional analysis of coronary computed tomography

Background

A high coronary artery calcium score (CACS) predicts a poor prognosis in patients with coronary artery disease. We examined the relationship between the bifurcation angle and the CACS of the left main (LM) and left anterior descending (LAD) arteries in patients suffering from chronic kidney disease (CKD).

Methods

We analyzed the data of 121 patients who underwent coronary computed tomography between October 2014 and June 2015 and whose estimated glomerular filtration rate (eGFR) was <60 ml/min/1.73 m². The LM-LAD bifurcation angle was measured by 3-dimensional coronary computed tomography. The CACS of the LM-LAD arteries was also calculated. We excluded stent recipients and patient who had undergone coronary artery bypass graft surgery.

Results

In the overall sample, the mean ± standard deviation (range) LM-LAD bifurcation angle was 35.9 ± 11.4° (6.8–79.4°) and mean CACS was 227 ± 351 (0 to 1,695). The mean LM-LAD arteries angle was 40.3° ± 10.0° in 39 patients whose CACS was ≥200, versus 33.8° ± 11.6° in 82 patients with CACS <200 (p = 0.003). A weak, but positive correlation (r = 0.269, p = 0.003) was observed between the LM-LAD arteries angle and CACS of the LM-LAD arteries. By multiple variable analysis, hemoglobin A1c, triglycerides, eGFR and the LM-LAD arteries angle were independent predictors of a high CACS of the LM-LAD arteries.

Conclusion

In patients with CKD, a wide LM-LAD arteries angle was associated with a high CACS of the LM-LAD arteries. The prognostic value of this observation warrants further evaluation.

Left Main Disease: What Is the Correct Approach to Revascularization?

Percutaneous coronary intervention of the left main coronary artery has evolved through registries and meta analyses, supported by results from the EXCEL [Everolimus-Eluting Stents (EES) or Bypass Surgery for Left Main Coronary Artery Disease] and NOBLE (Percutaneous Coronary Angioplasty versus Coronary Artery Bypass Grafting in Treatment of Unprotected Left Main Stenosis) trials as an acceptable alternative to coronary artery bypass grafting in patients with low and intermediate Syntax scores. Advances in stenting strategies and the availability of larger diameter drug-eluting stents improve patient safety and optimize procedural and patient outcomes.

Current Interventions for the Left Main Bifurcation

Contemporary clinical trials, registries, and meta-analyses, supported by recent results from the EXCEL (Everolimus-Eluting Stents or Bypass Surgery for Left Main Coronary Artery Disease) and NOBLE (Percutaneous Coronary Angioplasty Versus Coronary Artery Bypass Grafting in Treatment of Unprotected Left Main Stenosis) trials, have established percutaneous coronary intervention of left main coronary stenosis as a safe alternative to coronary artery bypass grafting in patients with low and intermediate SYNTAX (Synergy Between Percutaneous Coronary Intervention With Taxus and Cardiac Surgery) scores. As left main percutaneous coronary intervention gains acceptance, it is imperative to increase awareness for patient selection, risk scoring, intracoronary imaging, vessel preparation, and choice of stenting techniques that will optimize procedural and patient outcomes.

Contemporary Approach to Coronary Bifurcation Lesion Treatment

Coronary bifurcations are frequent and account for approximately 20% of all percutaneous coronary interventions. Nonetheless, they remain one of the most challenging lesion subsets in interventional cardiology in terms of a lower procedural success rate and increased rates of long-term adverse cardiac events. Provisional side branch stenting should be the default approach in the majority of cases and we propose easily applicable and reproducible stepwise techniques associated with low risk of failure and complications.

Quantitative angiography methods for bifurcation lesions: a consensus statement update from the European Bifurcation Club

Bifurcation lesions represent one of the most challenging lesion subsets in interventional cardiology. The European Bifurcation Club (EBC) is an academic consortium whose goal has been to assess and recommend the appropriate strategies to manage bifurcation lesions. The quantitative coronary angiography (QCA) methods for the evaluation of bifurcation lesions have been subject to extensive research. Single-vessel QCA has been shown to be inaccurate for the assessment of bifurcation lesion dimensions. For this reason, dedicated bifurcation software has been developed and validated. These software packages apply the principles of fractal geometry to address the "step-down" in the bifurcation and to estimate vessel diameter accurately. This consensus update provides recommendations on the QCA analysis and reporting of bifurcation lesions based on the most recent scientific evidence from in vitro and in vivo studies and delineates future advances in the field of QCA dedicated bifurcation analysis.

Percutaneous coronary intervention for coronary bifurcation disease: 11th consensus document from the European Bifurcation Club

Coronary bifurcations are involved in 15-20% of all percutaneous coronary interventions (PCI) and remain one of the most challenging lesions in interventional cardiology in terms of procedural success rate as well as long-term cardiac events. The optimal management of bifurcation lesions is, despite a fast growing body of scientific literature, the subject of considerable debate. The European Bifurcation Club (EBC) was initiated in 2004 to support a continuous overview of the field, and aims to facilitate a scientific discussion and an exchange of ideas on the management of bifurcation disease. The EBC hosts an annual, compact meeting, dedicated to bifurcations, which brings together physicians, engineers, biologists, physicists, epidemiologists and statisticians for detailed discussions. Every meeting is finalised with a consensus statement which reflects the unique opportunity of combining the opinions of interventional cardiologists with the opinions of a large variety of other scientists on bifurcation management. The present 11th EBC consensus document represents the summary of the up-to-date EBC consensus and recommendations. It points to the fact that there is a multitude of strategies and approaches to bifurcation stenting within the provisional strategy and in the different two-stent strategies. The main EBC recommendation for PCI of bifurcation lesions remains to use main vessel (MV) stenting with a proximal optimisation technique (POT) and provisional side branch (SB) stenting as a preferred approach. The consensus document covers a moving target. Much more scientific work is needed in non-left main (LM) and LM bifurcation lesions for continuous improvement of the outcome of our patients.

Optimal Revascularization Strategy on Medina 0,1,0 Left Main Bifurcation Lesions in Type 2 Diabetes

Aim. Diabetes mellitus (DM) is a major risk factor for cardiovascular disease. The implications of a diagnosis of DM are as severe as the diagnosis of coronary artery disease. For many patients with complex coronary artery disease, optimal revascularization strategy selection and optimal medical therapy are equally important. In this study, we compared the hemodynamic results of different stenting techniques for Medina 0,1,0 left main bifurcation lesions. Methods. We use idealized left main bifurcation models and computational fluid dynamics analysis to evaluate hemodynamic parameters which are known to affect the risk of restenosis and thrombosis at stented bifurcation. The surface integrals of time-averaged wall shear stress (TAWSS) and oscillatory shear index (OSI) at bifurcation site were quantified. Results. Crossover stenting without final kissing balloon angioplasty provided the most favorable hemodynamic results (integrated values of TAWSS = 2.96 × 10^-4 N, OSI = 4.75 × 10^-6 m²) with bifurcation area subjected to OSI values >0.25, >0.35, and >0.45 calculated as 0.39 mm², 0.06 mm², and 0 mm², respectively. Conclusion. Crossover stenting only offers hemodynamic advantages over other stenting techniques for Medina 0,1,0 left main bifurcation lesions and large bifurcation angle is associated with unfavorable flow profiles.

Coronary CT angiography in calcified coronary plaques: Comparison of diagnostic accuracy between bifurcation angle measurement and coronary lumen assessment for diagnosing significant coronary stenosis

BACKGROUND

To investigate the diagnostic value of coronary CT angiography (CCTA) by bifurcation angle measurement in the assessment of calcified plaques compared to conventional coronary lumen analysis.

METHODS

Fifty-three patients with calcified plaques identified on CCTA in the left coronary artery were included in the study. Minimal lumen diameter (MLD) and bifurcation angle between the left anterior descending (LAD) and left circumflex (LCx) arteries were measured and compared between CCTA and invasive coronary angiography (ICA), while the areas under the curves (AUCs) by receiver-operating characteristic curve analysis (ROC) were compared between CCTA and ICA with regard to the diagnostic value of using bifurcation angle as a criterion.

RESULTS

On a per-vessel assessment, the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) and 95% confidence interval (CI) with the use of bifurcation angle for determining coronary stenosis were 100% (86%, 100%), 79% (59%, 92%), 81% (62%, 92%), and 100% (85%, 100%) for CCTA, and 100% (86%, 100%), 82% (63%, 94%), 83% (65%, 94%), and 100% (85%, 100%) for ICA, respectively. While the sensitivity and NPV remained unchanged, the specificity and PPV of CCTA by MLD were 33% (21%, 47%) and 43% (31%, 56%). The AUCs by ROC curve analysis for CCTA and ICA bifurcation angle measurements demonstrated no significant difference (p>0.05, 0.79 vs 0.86, and 0.70 vs 0.68 at the LAD and LCx assessment, respectively).

CONCLUSION

Coronary CT angiography by bifurcation angle measurement shows significant improvement in the diagnosis of calcified plaques with diagnostic value comparable to invasive coronary angiography.