Stenting of bifurcation lesions: classification, treatments, and results

Comparison of Outcomes Between 1- and 2-Stent Techniques for Medina Classification 0.0.1 Coronary Bifurcation Lesions

BACKGROUND

Although Medina 0.0.1 bifurcation lesions are often treated by percutaneous coronary intervention (PCI) in real-world practice, the optimal revascularization strategy for this lesion is uncertain.

OBJECTIVES

The current study aimed to compare the clinical outcomes between 1- and 2-stent strategies in patients treated with PCI for Medina 0.0.1 bifurcation lesions.

METHODS

The extended BIFURCAT (Combined Insights From the Unified RAIN [Very Thin Stents for Patients with Left Main or Bifurcation in Real Life] and COBIS [Coronary Bifurcation Stenting] Bifurcation Registries) registry was obtained by patient-level merging the dedicated bifurcation COBIS II, III, and RAIN registries. Among 8,434 patients with bifurcation lesions undergoing PCI, 345 (4.1%) with Medina 0.0.1 lesions were selected for the current analysis. The primary endpoint was major adverse cardiac event (MACE, a composite of all-cause death, myocardial infarction, target vessel revascularization, and stent thrombosis) at 800 days.

RESULTS

In the total population, 209 patients (60.6%) received PCI with a 1-stent strategy and the remaining 136 patients (39.4%) with a 2-stent strategy. There was a tendency for higher use of a 1-stent strategy over time (36.0%, 47.4%, and 90.4% in 2003-2009, 2010-2014, and 2015-2017, respectively; P for trend < 0.001). For the treatment of Medina 0.0.1 lesions, there was no significant difference in the risk of MACE between 1- and 2-stent strategies (1 stent vs 2 stent, 14.3% vs 13.9%; HR: 1.034; 95% CI: 0.541-1.977; P = 0.92). The risk of MACE was also not significantly different when stratifying into 3 groups (1-stent crossover only, 1-stent with strut opening, and 2-stent strategy).

CONCLUSIONS

In patients with a Medina 0.0.1 type bifurcation lesion, PCI with a 1-stent strategy showed comparable outcomes to that of a 2-stent strategy. (Coronary Bifurcation Stenting II [COBIS II]; NCT01642992; Coronary Bifurcation Stenting III [COBIS III]; NCT03068494; Very Thin Stents for Patients with Left Main or Bifurcation in Real Life [RAIN]; NCT03544294).

Drug-coated balloon combined with drug-eluting stent for the treatment of coronary bifurcation lesions: insights from the HYPER study

True coronary bifurcation lesions (CBL) represent a challenging scenario for percutaneous coronary interventions (PCI), and are associated with a higher risk of target lesion failure (TLF), particularly when two stents are implanted. A hybrid strategy combining a drug-eluting stent (DES) in the main branch, and a drug-coated balloon in the side branch may improve outcomes by reducing the total stent length while maintaining an effective anti-prolipherative action. In this sub-study of the HYPER trial, 50 patients with true CBL were treated with a hybrid strategy: procedural success was 96%, one case of peri-procedural myocardial infarction and one case of TLF (in a DES-treated segment) at 1 year were reported. This study suggests that such a hybrid strategy may be a safe and effective option for true CBL PCI, and warrants additional investigations to compare outcomes with standard of care strategies.

Clinical use of optical coherence tomography during percutaneous coronary intervention and coronary procedures in Southeast Asia: a survey-based expert consensus summary

Optical coherence tomography (OCT), an established intravascular imaging technique, enables rapid acquisition of high-resolution images during invasive coronary procedures to assist physician decision-making. OCT has utility in identifying plaque/lesion morphology (e.g., thrombus, degree of calcification, and presence of lipid) and vessel geometry (lesion length and vessel diameter) and in guiding stent optimisation through identification of malapposition and underexpansion. The use of OCT guidance during percutaneous coronary interventions (PCI) has demonstrated improved procedural and clinical outcomes in longitudinal registries, although randomised controlled trial data remain pending. Despite growing data and guideline endorsement to support OCT guidance during PCI, its use in different countries is not well established. This article is based on an advisory panel meeting that included experts from Southeast Asia (SEA) and is aimed at understanding the current clinical utility of intracoronary imaging and OCT, assessing the barriers and enablers of imaging and OCT adoption, and mapping a path for the future of intravascular imaging in SEA. This is the first Southeast Asian consensus that provides insights into the use of OCT from a clinician's point of view.

Drug-coated balloon in the treatment of coronary bifurcation lesions: A hope or hype?

When compared to non-bifurcation lesions, percutaneous coronary intervention in coronary bifurcation lesions is technically demanding and has historically been limited by lower procedural success rates and inferior clinical results. Following the development of drug-eluting stents, dramatically better results have been demonstrated. In most of the bifurcation lesions, the provisional technique of implanting a single stent in the main branch (MB) remains the default approach. However, some cases require more complex two-stent techniques which carry the risk of side branch (SB) restenosis. The concept of leaving no permanent implant behind is appealing because of the complexity of bifurcation anatomy with significant size mismatch between proximal and distal MB which may drive rates of in-stent restenosis and the potential impact of MB stenting affecting SB coronary flow dynamics. With the perspective of leaving lower metallic burden, a drug-coated balloon (DCB) has been utilized to treat bifurcations in both the MB and SB. The author gives an overview of the existing state of knowledge and prospects for the future for using DCB to treat bifurcation lesions.

Buddy Balloon versus Buddy Wire Technique Regarding Accuracy of Stent Placement during Percutaneous Coronary Intervention

We aimed to evaluate whether the buddy balloon technique (BBT) is superior to the buddy wire technique (BWT) with regard to the accuracy of stent placement during percutaneous coronary intervention (PCI).We enrolled patients who had been identified with significant stent movement before the stent was dilated at five hospitals and were randomly converted to either the BBT or BWT technique. The primary endpoints were the incidence of technical success and major adverse cardiovascular events (cardiac death, myocardial infarction, target lesion revascularization, and in-stent restenosis) at 2 years of follow-up. The secondary endpoints were the contrast volume used for the procedure and the total procedural time.From August 2018 to July 2019, 66 patients were enrolled, with 33 patients in each group. All patients were successfully followed up to 2 years. At the primary endpoints, compared with patients treated using BWT, those in the BBT group showed significantly better technical success (93.94% versus 39.39%, respectively; P < 0.0001). There was no significant difference in the incidence of major cardiovascular adverse events (6.06% versus 12.12%, respectively; P = 0.392). At the secondary endpoints, the contrast volume used for the procedure was lower with BBT (85.97 ± 22.45 versus 115.00 ± 21.45 mL, respectively; P < 0.0001); similarly, the total procedural time was shorter with BBT (65.94 ± 12.14 versus 74.33 ± 15.36 minutes, respectively; P < 0.0001).BBT could better restrict stent movement and facilitate precise stent deployment, with significant superiority over BWT. In addition, BBT can reduce the procedural time and contrast dose.

Management of calcified coronary artery bifurcation lesions

Calcified coronary artery bifurcation lesions (CBL) remain a challenge for the interventional cardiologist. Evidence regarding treatment of CBL is minimal. Optimal plaque modification is the most important step prior to stent deployment. Provisional stenting is the preferred strategy for most bifurcation lesions. However, two-stent strategy should be considered for BL with compromised large SB (>2.5 mm) supplying a large territory, >70% SB stenosis and lesions more than 5 mm long. In this contemporary review article, we present a simplified approach to treating CBL and demonstrate the approach to specific case examples using our newly developed mobile application, BifurcAID.

Contemporary Management of Isolated Ostial Side Branch Disease: An Evidence-based Approach to Medina 001 Bifurcations

The optimal management of bifurcation lesions has received significant interest in recent years and remains a matter of debate among the interventional cardiology community. Bifurcation lesions are encountered in approximately 21% of percutaneous coronary intervention procedures and are associated with an increased risk of major adverse cardiac events. The Medina classification has been developed in an attempt to standardise the terminology when describing bifurcation lesions. The focus of this article is on the management of the Medina 0,0,1 lesion (‘Medina 001’), an uncommon lesion encountered in <5% of all bifurcations. Technical considerations, management options and interventional techniques relating to the Medina 001 lesion are discussed. In addition, current published data supporting the various proposed interventional treatment strategies are examined in an attempt to delineate an evidence-based approach to this uncommon lesion.

Stent Size Optimization in the Femoral Bifurcation Using a Fractal Model: A Morphological Analysis

OBJECTIVES

Stenting of common femoral artery (CFA) bifurcation lesions is complex due to harmonious asymmetric geometry between the CFA and deep or superficial femoral artery. In order to ensure an optimal flow, the stents must be implanted according to the diameter of the CFA and the diameter of the daughter vessels. The aim of this study was to validate a mathematical formula for the CFA bifurcation in order to optimize the implantation of stents in this bifurcation with a fast and efficient method.

MATERIALS/METHODS

We retrospectively included all patients who underwent transcatheter aortic valve implantation and who had a healthy CFA bifurcation on the CT-scan. Diameters of the mother vessel (D_m), daughter vessels (D_l: larger vessel; D_s: smaller vessel), and the ratio between the two were calculated. According to the latter, the following linear model was proposed: [D_m = (D_m/D_l + D_s) × (D_l + D_s)] and was compared to the four existing models (Murray, HK, Flow, Finet). Finally, we calculated the relative error between the prediction of the four models and the measurements.

RESULTS

Overall, 110 CFA bifurcations were included. Mean CFA diameter was 7.75 ± 1.67 mm. Mean D_l diameter was 5.79 ± 1.21 mm and mean D_s diameter was 5.23 ± 1.09 mm. A reduction of 25 % was seen between the CFA and the larger daughter-vessel. The mean ratio between the CFA and the daughter vessels was 0.71. Our model [D_m = 0.71× (D_l + D_s)] and the flow law were the most accurate (relative difference of 1.59 ± 11.97% and 1.01 ± 11.94%, respectively). However, Murray's law had a statistically significant deviation from the real mother-vessel diameter (P < 0.001).

CONCLUSIONS

We developed a simple fractal ratio between CFA and daughter vessels, which could be easily used in daily practice during CFA percutaneous reconstruction to identify the optimal diameters of the diseased vessels.

Optical coherence tomography: fundamentals and clinical utility

Although coronary angiography is the standard method employed to assess the severity of coronary artery disease and to guide treatment strategies, it provides only 2D image of the intravascular lesions. In contrast, intravascular imaging modalities such as optical coherence tomography (OCT) produce cross-sectional images of the coronary arteries at a far greater spatial resolution, capable of accurately determining vessel size as well as plaque morphology, eliminating many of the disadvantages inherent to angiography. This review will discuss the role of OCT in the catherization laboratory for the assessment and management of coronary disease.

Provisional stenting or not provisional stenting: seven critical points for bifurcations treatment with a glimpse on left main bifurcation stenting

Stenting of coronary bifurcation lesions represents a challenge for the interventional cardiologist. A bifurcation lesion could be treated with several techniques. Therefore, it is of paramount importance to decide the strategical approach at the beginning of the procedure evaluating the patient's bifurcation anatomy, the angle between main and side branch, plaque burden at the level of the carina, and size of the side branch. Although it is clear that all bifurcation's treatment techniques have each one their advantages and disadvantages, provisional stenting remains the gold-standard technique, because it leaves the possibility to switch to other technical solutions with optimal angiographic and long-term clinical results. In this review, different tips and tricks for left main and bifurcation stenting are debated.

Computational Simulations of Provisional Stenting of a Diseased Coronary Artery Bifurcation Model

Although stenting of non-branched arterial segments has acceptable clinical outcomes, in-stent restenosis (ISR) and stent thrombosis remain clinically significant issues for vascular bifurcations (15-28% restenosis). Local fluid and solid stresses appear to play an important role in restenosis and thrombosis. The combined role of wall shear stress (WSS) and circumferential wall stresses (CWS) is unclear in the case of stenting at vascular bifurcations. Using numerical simulations, we computed the fluid shear, solid stresses and the stress ratio at the the bifurcation region. Stenting of main vessel increased the maximum CWS in the the side branch (SB), resulting in a nearly two-fold increase of stress ratio in the SB compared to the MB (5.1 × 10⁵ vs. 9.2 × 10⁵). The existence of plaque decreased WSS and increased CWS near the carina, increasing the stress ratio at the SB. The changes of stress ratio were highly consistent with clinical data on bifurcation stenting. Fluid dynamics and solids mechanics should be considered in planning of stenting for a specific bifurcation, as their combined biomechanical effect may play an important role in stent restenosis and thrombosis.

Comparison of Computed Tomography Angiography Versus Invasive Angiography to Assess Medina Classification in Coronary Bifurcations

The Medina classification is used to determine the presence of significant stenosis (≥50%) within each of the 3 arterial segments of coronary bifurcation in invasive coronary angiography (ICA). The utility of coronary computed tomography angiography (coronary CTA) for assessment of Medina classification is unknown. We aimed to compare the agreement and reproducibility of Medina classification between ICA and coronary CTA, and evaluate its ability to predict side branch (SB) occlusion following percutaneous coronary intervention (PCI). In total 363 patients with 400 bifurcations were included, and 28 (7%) SB occlusions among 26 patients were noted. Total agreement between CTA and ICA for assessment of Medina class was poor (kappa = 0.189), and discordance between both modalities was noted in 253 (63.3%) lesions. Larger diameter ratio between main vessel and SB in CTA, and larger bifurcation angle in ICA were independently associated with discordant Medina assessment. Whereas the interobserver agreement on Medina classification in CTA was moderate (kappa = 0.557), only fair agreement (kappa = 0.346) was observed for ICA. Finally, Medina class with any proximal involvement of main vessel and SB (1.X.1) on CTA or ICA was the most predictive of SB occlusion following PCI with no significant differences between both modalities (area under the curve 0.686 vs 0.663, p = 0.693, respectively). In conclusion, Medina classification was significantly affected by the imaging modality, and coronary CTA improved reproducibility of Medina classification compared with ICA. Both CTA and ICA-derived Medina class with any involvement of the proximal main vessel and SB was predictive of SB occlusion following PCI.

The improvement of the shear stress and oscillatory shear index of coronary arteries during Enhanced External Counterpulsation in patients with coronary heart disease

Background

Enhanced External Counterpulsation (EECP) can chronically relieve ischemic chest pain and improve the prognosis of coronary heart disease (CHD). Despite its role in mitigating heart complications, EECP and the mechanisms behind its therapeutic nature, such as its effects on blood flow hemodynamics, are still not fully understood. This study aims to elucidate the effect of EECP on significant hemodynamic parameters in the coronary arterial tree.

Methods

A finite volume method was used in conjunction with the inlet pressure wave (surrogated by the measured aortic pressure) before and during EECP and outlet flow resistance, assuming the blood as newtonian fluid. The time-average wall shear stress (TAWSS) and oscillatory shear index (OSI) were determined from the flow field.

Results

Regardless of the degree of vascular stenosis, hemodynamic conditions and flow patterns could be improved during EECP. In comparison with the original tree, the tree with a severe stenosis (75% area stenosis) demonstrated more significant improvement in hemodynamic conditions and flow patterns during EECP, with surface area ratio of TAWSS risk area (SAR-TAWSS) reduced from 12.3% to 6.7% (vs. SAR-TAWSS reduced from 7.2% to 5.6% in the original tree) and surface area ratio of OSI risk area (SAR-OSI) reduced from 6.8% to 2.5% (vs. SAR-OSI of both 0% before and during EECP in the original tree because of mild stenosis). Moreover, it was also shown that small ratio of diastolic pressure (D) and systolic pressure (S) (D/S) could only improve the hemodynamic condition mildly. The SAR-TAWSS reduction ratio significantly increased as D/S became larger.

Conclusions

A key finding of the study was that the improvement of hemodynamic conditions along the LMCA trees during EECP became more significant with the increase of D/S and the severity degree of stenoses at the bifurcation site. These findings have important implications on EECP as adjuvant therapy before or after percutaneous coronary intervention (PCI) in patients with diffuse atherosclerosis.

Prevalence and characteristics of dual left anterior descending artery in adult patients undergoing coronary angiography

Aim: To determine the prevalence and characteristics of dual left anterior descending artery (LAD) in adults undergoing catheter coronary angiography. Materials & methods: We identified cases with dual LAD by retrospectively analyzing 3233 angiograms done from January 2017 to June 2019. Results: Dual LAD was seen in 22 patients (0.68%). We identified type I dual LAD in 14 cases, type II in 7 cases and type III in 1 case. Significant stenosis was seen in proximal part of long LAD in 12 cases, in LAD proper in 7 cases and in proximal part of short LAD in 4 cases. Conclusion: Dual LAD is a rare anomaly. Its sound knowledge is essential for proper management of patients with coronary artery disease.

Usefulness of longitudinal reconstructed optical coherence tomography images for predicting the need for the reverse wire technique during coronary bifurcation interventions

OBJECTIVES

The aim is to investigate the usefulness of longitudinal reconstructed optical coherence tomography (OCT) images in selecting the reverse wire (RW) technique for inserting a guidewire into a side branch (SB).

BACKGROUND

It is sometimes necessary to protect the SB with a guidewire to prevent SB complications in PCI for bifurcation lesions. The RW is a novel method for guidewire insertion into an extremely angulated SB when the standard antegrade wire (AW) approach is difficult.

METHODS

This retrospective study included 46 consecutive patients who underwent OCT-guided PCI in bifurcation lesions with significant SB stenosis. Patients were divided into two groups: 36 patients with successful guidewire crossing using the AW (AW group) and 10 patients with unsuccessful AW but successful RW guidewire crossing (RW group). SB angle and branch point (BP) slope, defined as the angle between the line connecting the proximal and distal BPs and the vertical, were measured using longitudinal reconstructed OCT images.

RESULTS

The RW group had a significantly larger SB angle and higher BP slope than the AW group (108.7 ± 11.4° vs. 76.2 ± 14.9°; P < 0.0001, 128.7 ± 31.6° vs. 82.9 ± 33.6°; P = 0.0004, respectively). Receiver operating characteristic curve analysis indicated that SB angle ≥ 100° and BP slope ≥ 120° are optimal cutoff values for predicting the need for RW (area under the curve 0.97, sensitivity 90.0%, specificity 91.7%; area under the curve 0.83, sensitivity 80.0%, specificity 86.1%, respectively).

CONCLUSIONS

Longitudinal reconstructed OCT is useful for selecting the wiring technique for bifurcation lesions.

Hemodynamic Effects on Particle Targeting in the Arterial Bifurcation for Different Magnet Positions

The present study investigated the possibilities and feasibility of drug targeting for an arterial bifurcation lesion to influence the host healing response. A micrometer sized iron particle was used only to model the magnetic carrier in the experimental investigation (not intended for clinical use), to demonstrate the feasibility of the particle targeting at the lesion site and facilitate the new experimental investigations using coated superparamagnetic iron oxide nanoparticles. Magnetic fields were generated by a single permanent external magnet (ferrite magnet). Artery bifurcation exerts severe impacts on drug distribution, both in the main vessel and the branches, practically inducing an uneven drug concentration distribution in the bifurcation lesion area. There are permanently positioned magnets in the vicinity of the bifurcation near the diseased area. The generated magnetic field induced deviation of the injected ferromagnetic particles and were captured onto the vessel wall of the test section. To increase the particle accumulation in the targeted region and consequently avoid the polypharmacology (interaction of the injected drug particles with multiple target sites), it is critical to understand flow hemodynamics and the correlation between flow structure, magnetic field gradient, and spatial position.

A novel technique for coronary bifurcation intervention: Double rewire crush technique and its clinical outcomes after 2 years of follow-up

OBJECTIVES

To describe procedural details of the double rewire (DR) crush technique, a novel modified crush technique, and report the clinical outcomes of patients who underwent the procedure.

BACKGROUND

In the management of complex bifurcation lesions, there is a need to use elective two-stent techniques that stent the side branch (SB) before main vessel (MV) stenting and keep SB open.

METHODS

We studied 48 patients with 49 bifurcation lesions who underwent percutaneous coronary intervention (PCI) using the DR-crush technique between January and December 2013. Baseline, postprocedural, and follow-up quantitative coronary angiographic analyses were performed. Procedural characteristics and clinical outcomes at follow-up were assessed.

RESULTS

Majority of the patients (60.4%, 29/48) had acute coronary syndrome. Most bifurcation lesions (77.6%, 38/49) were classified as Medina 1, 1, 1. Final kissing balloon inflation was successfully performed in all patients. After PCI, MV and SB of all patients had Thrombolysis In Myocardial Infarction 3 blood flow. None of the patients had MV or SB diameter stenosis ≥50% after PCI. At a mean follow-up period of 2.4 years, target vessel revascularization occurred in 2.1% and myocardial infarction in 2.1%. No deaths occurred in this period.

CONCLUSIONS

The DR-crush technique is feasible in coronary bifurcation stenting. Patients who underwent this procedure had relatively low incidence of adverse events. Larger studies are warranted for further confirmation of the findings.

True double bifurcation lesions: new application of the self-expandable Axxess stent and review of literature with dedicated bifurcation devices

Complex coronary artery bifurcation lesions occurred in hard clinical scenarios, such as acute coronary syndromes, may represent a challenge for interventional cardiologists, with not-defined general consensus on treatment. Even if provisional stenting is the most common option used to restore rapidly the coronary branches flow, improvements in industrial technologies and design of new dedicated bifurcation devices might open new modalities of treatment in these complex cases. The Axxess stent (Biosensors Europe SA, Morges, Switzerland) is a self-expanding biolimus-eluting conical V-shape stent, specifically designed to treat "easily" coronary artery bifurcation lesions, with reported favorable long-term clinical results in stable patients compared to a provisional technique. We report for the first time the feasibility to use this device in a case of "true double coronary bifurcation lesion" occurred in the context of acute coronary syndrome. Moreover, we reviewed studies with bifurcation dedicated devices and available cases of "true double bifurcation lesions", underlying advantages/disadvantages of using one device over the others during acute coronary syndrome.

Understanding the Coronary Bifurcation Stenting

Coronary bifurcation stenting is still complex and associated with a high risk of stent thrombosis and restenosis even with contemporary techniques. Although provisional approach has been proved to be the standard strategy of treatment, There is still lack of evidences for multiple steps of the procedure. For so many years we have been focused on the optimization of side branch (SB), but the clinical outcome is mostly dependent on the main vessel (MV) stenting. The optimal expansion of MV stent without the compromise of SB is the ultimate goal to achieve in the coronary bifurcation stenting. Understanding the anatomy and physiology of coronary bifurcation lesion should be the most important step to this goal. The relationship of vessel diameter between branches and the anatomical and functional significance of plaque shift and carina shift are two most important concepts to understand. They are the science behind the predictors of SB occlusion, and the rationale of proximal optimization technique and final kissing ballooning. This specific review will be devoted to review those concepts as well as clinical evidences to support them.

Comparison of the Predictive Roles of Risk Scores of In-Hospital Major Adverse Cardiovascular Events in Patients with Non-ST Elevation Myocardial Infarction Undergoing Percutaneous Coronary Intervention

OBJECTIVE

We evaluated the relationship between various risk scores (SYNTAX score [SS], SYNTAX score-II [SS-II], thrombolysis in myocardial infarction [TIMI] risk scores, and Global Registry of Acute Coronary Events [GRACE] risk scores) and major adverse cardiovascular events (MACE) in non-ST elevation myocardial infarction (NSTEMI) patients undergoing percutaneous coronary intervention (PCI).

SUBJECTS AND METHODS

The study population were selected from among 589 patients who underwent coronary angiography with a diagnosis of NSTEMI. TIMI and GRACE risk scores were calculated. SS and SS-II were calculated in all patients, and points were added according to the predefined algorithm, taking into account the other 6 clinical variables being monitored (age, sex, left ventricular ejection fraction, creatinine clearance, chronic obstructive pulmonary disease, and peripheral artery disease). Patients were classified into tertile 1 (SS < 22), tertile 2 (SS 23-32), and tertile 3 (SS > 32).

RESULTS

The group with high SS-II for PCI values in the risk scores were observed from tertile 1 to tertile 3 (from 25.0 ± 7.7 to 31.6 ± 9.4, p < 0.001, respectively). The SS-II score in patients with PCI was an independent predictor of MACE, in-hospital mortality, nonfatal myocardial infarction, and stent thrombosis (OR 1.082, 95% CI 1.036-1.131, p < 0.001). The overall MACE, in-hospital mortality, and nonfatal myocardial infarction rates were significantly higher in the high SS-II for PCI group (p < 0.001).

CONCLUSION

TIMI and GRACE risk scores were able to predict MACE. In addition to these, SS-II was also able to predict in-hospital mortality, nonfatal myocardial infarction, and stent thrombosis.

SYNTAX, STS and EuroSCORE – How good are they for risk estimation in atherosclerotic heart disease?

Tests that enable prediction of adverse outcome after surgical or nonsurgical intervention in cardiac patients are of great importance since they can help guide clinical decision making. The new evolving percutaneous therapeutic techniques combined with the currently available risk scoring systems require improved prediction models. In the context of steadily improving surgical techniques and perioperative care, on the one hand, and the inadequacy of regional patient data sets to provide generally applicable risk prediction base, on the other, there is need for adaption and recalibration of scoring systems some of which are partly outdated but still widely in use. The accuracy of predictive models depends on their proper application as well as the knowledge of their individual strengths and weaknesses. The EuroSCORE and the STS score take into consideration some risk factors associated with mortality, whereas the SYNTAX score relies solely on coronary anatomy and lesion characteristics. A combination of selected score components from the EuroSCORE, assessing the mortality risk, and those from the SYNTAX score, reflecting the coronary artery disease complexity, can be expected to yield more accurate results in estimating risk in individual patients. In this review, the predictive ability of the SYNTAX score, the STS score and the EuroSCORE will be discussed.

Final kissing balloon inflation for coronary bifurcation lesions treated with single-stent technique : A meta-analysis

BACKGROUND

The efficacy of final kissing balloon (FKB) inflation in one-stent techniques for bifurcation lesions is controversial. The goal of the present study was to investigate the impact of FKB on long-term clinical outcomes in one-stent strategies.

METHODS

A literature search of the PubMed, Embase, and Cochrane Library databases was undertaken through August 2017. The primary outcome was major adverse cardiac events (MACE), defined as the composite of cardiac death, myocardial infarction, and target lesion revascularization. Overall hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated using the random-effects model.

RESULTS

Ten studies comprising 7364 patients treated with a one-stent technique were included in the analysis. Overall, FKB did not demonstrate a significant reduction in MACE compared with non-FKB in both randomized trials (HR: 1.13; 95% CI: 0.65-1.98) and observational studies (HR: 0.86; 95% CI: 0.61-1.20). The risk of cardiac death (HR: 0.89; 95% CI: 0.53-1.49), myocardial infarction (HR: 0.76; 95% CI: 0.53-1.09), and target lesion revascularization (HR: 0.96; 95% CI: 0.74-1.23) was also similar in both groups.

CONCLUSION

FKB may not be mandatory and a selective FKB strategy might be more justified in one-stent techniques for bifurcation lesions.

A "Jail Escape Technique" (JET) for distal side branch wiring during provisional stenting: Feasibility and first-in-man study

OBJECTIVE

To evaluate the feasibility of a novel technique for achieving distal SB access and improve strut apposition during provisional stenting.

BACKGROUND

While distal rewiring and stent expansion toward the side branch (SB) are associated with better results during provisional stenting of coronary artery bifurcation lesions, these techniques are technically challenging and often leave unopposed struts near the carina.

METHODS

The "Jail Escape Technique" (JET) is performed by passing the proximal tip of the SB wire between the main vessel (MV) stent struts and balloon before implantation, allowing the MV stent to push the SB wire against the distal part of the carina. The MV stent can then be deployed without jailing the SB wire. Distal SB access and strut distribution at the carina were tested in phantom and swine models. Stent distortion, dislodgement forces, and material damage were evaluated with tensile testing. Human feasibility was then tested on 32 patients.

RESULTS

Preclinical testing demonstrated that the SB wire was located at the most distal part of the carina and no strut malapposition at the carina was present after balloon inflation. Stent distortion, dislodgement forces, or material damage were not affected. JET was successfully performed in 30 of 32 patients. No major adverse cardiovascular events occurred in any patient at 6-month follow-up.

CONCLUSION

The "JET" enables distal SB access and eliminates strut malapposition at the carina. Further studies with larger numbers of patients are needed to further investigate this technique.

Plaque imaging with CT-a comprehensive review on coronary CT angiography based risk assessment

CT based technologies have evolved considerably in recent years. Coronary CT angiography (CTA) provides robust assessment of coronary artery disease (CAD). Early coronary CTA imaging-as a gate-keeper of invasive angiography-has focused on the presence of obstructive stenosis. Coronary CTA is currently the only non-invasive imaging modality for the evaluation of non-obstructive CAD, which has been shown to contribute to adverse cardiac events. Importantly, improved spatial resolution of CT scanners and novel image reconstruction algorithms enable the quantification and characterization of atherosclerotic plaques. State-of-the-art CT imaging can therefore reliably assess the extent of CAD and differentiate between various plaque features. Recent studies have demonstrated the incremental prognostic value of adverse plaque features over luminal stenosis. Comprehensive coronary plaque assessment holds potential to significantly improve individual risk assessment incorporating adverse plaque characteristics, the extent and severity of atherosclerotic plaque burden. As a result, several coronary CTA based composite risk scores have been proposed recently to determine patients at high risk for adverse events. Coronary CTA became a promising modality for the evaluation of functional significance of coronary lesions using CT derived fractional flow reserve (FFR-CT) and/or rest/dynamic myocardial CT perfusion. This could lead to substantial reduction in unnecessary invasive catheterization procedures and provide information on ischemic burden of CAD. Discordance between the degree of stenosis and ischemia has been recognized in clinical landmark trials using invasive FFR. Both lesion stenosis and composition are possibly related to myocardial ischemia. The evaluation of lesion-specific ischemia using combined functional and morphological plaque information could ultimately improve the diagnostic performance of CTA and thus patient care. In this review we aimed to summarize current evidence on comprehensive coronary artery plaque assessment using coronary CTA.

Bifurcation Culprit Lesions in ST-segment Elevation Myocardial Infarction: Procedural Success and 5-year Outcome Compared With Nonbifurcation Lesions

INTRODUCTION AND OBJECTIVES

We assessed short- and long-term outcomes of primary angioplasty in ST-segment elevation myocardial infarction by comparing bifurcation culprit lesions (BCL) with non-BCL.

METHODS

Observational study with a propensity score matched control group. Among 2746 consecutive ST-segment elevation myocardial infarction patients, we found 274 (10%) patients with BCL. The primary outcome was a composite endpoint including all-cause death, myocardial infarction, coronary artery bypass grafting or target vessel revascularization, assessed at 30-days and 5-years.

RESULTS

Baseline characteristics showed no differences after propensity matching (1:1). In the BCL group, the most frequent strategy was provisional stenting of the main branch (84%). Compared with the non-BCL group, the procedures were technically more complex in the BCL group in terms of need for balloon dilatation (71% BCL vs 59% non-BCL; P = .003), longer procedural time (70 ± 29minutes BCL vs 62.8 ± 28.9minutes non-BCL; P = .004) and contrast use (256.2 ± 87.9mL BCL vs 221.1 ± 82.3mL non-BCL; P < .001). Main branch angiographic success was similar (93.4% BCL vs 93.8% non-BCL; P = .86). Thirty-day all-cause mortality was similar between groups: 4.7% BCL vs 5.1% non-BCL; P = .84. At the 5-year follow-up, there were no differences in all-cause death (12% BCL vs 13% non-BCL; P = .95) or the combined event (22% BCL vs 21% non-BCL; P = .43).

CONCLUSIONS

Primary angioplasty of a BCL was technically more complex; however, main branch angiographic success was similar, and there were no differences in long-term prognosis compared with non-BCL patients.

Biomechanical impact of provisional stenting and balloon dilatation on coronary bifurcation: clinical implications

In-stent restenosis (ISR) and stent thrombosis remain clinically significant problems for bifurcations. Although the role of wall shear stress (WSS) has been well investigated, the role of circumferential wall stresses (CWS) has not been well studied in provisional stenting with and without final kissing balloon (FKB). We hypothesized that the perturbation of CWS at the SB in provisional stenting and balloon dilatation is an important factor in addition to WSS, and, hence, may affect restenosis rates (i.e., higher CWS correlates with higher restenosis). To test this hypothesis, we developed computational models of stent, FKB at bifurcation, and finite element simulations that considered both fluid and solid mechanics of the vessel wall. We computed the stress ratio (CWS/WSS) to show potential correlation with restenosis in clinical studies (i.e., higher stress ratio correlates with higher restenosis). Our simulation results show that stenting in the main branch (MB) increases the maximum CWS in the side branch (SB) and, hence, yields a higher stress ratio in the SB, as compared with the MB. FKB dilatation decreases the CWS and increases WSS, which collectively lowers the stress ratio in the SB. The changes of stress ratio were correlated positively with clinical data in provisional stenting and FKB. Both fluid and solid mechanics need to be evaluated when considering various stenting techniques at bifurcations, as solid stresses also play an important role in clinical outcome. An integrative index of bifurcation mechanics is the stress ratio that considers both CWS and WSS.NEW & NOTEWORTHY Although the role of wall shear stress (WSS) has been well investigated, the role of circumferential wall stresses (CWS) has not been well studied in provisional stenting with and without final kissing balloon. Both fluid and solid mechanics need to be evaluated when considering various stenting techniques at bifurcations. An integrative index of bifurcation mechanics is the stress ratio that considers both CWS and WSS.

A randomised comparison of Conventional versus Intentional straTegy in patients with high Risk prEdiction of Side branch OccLusion in coronary bifurcation interVEntion: rationale and design of the CIT-RESOLVE trial

INTRODUCTION

The intentional strategy (aggressive side branch (SB) protection strategy: elective two-stent strategy or jailed balloon technique) is thought to be associated with lower SB occlusion rate than conventional strategy (provisional two-stent strategy or jailed wire technique). However, most previous studies showed comparable outcomes between the two strategies, probably due to no risk classification of SB occlusion when enrolling patients. There is still no randomised trial compared the intentional and conventional strategy when treating bifurcation lesions with high risk of SB occlusion. We aim to investigate if intentional strategy is associated with significant reduction of SB occlusion rate compared with conventional strategy in high-risk patients.

METHODS AND ANALYSIS

The Conventional versus Intentional straTegy in patients with high Risk prEdiction of Side branch OccLusion in coronary bifurcation interVEntion (CIT-RESOLVE) is a prospective, randomised, single-blind, multicentre clinical trial comparing the rate of SB occlusion between the intentional strategy group and the conventional strategy group (positive control group) in a consecutive cohort of patients with high risk of side branch occlusion defined by V-RESOLVE score, which is a validated angiographic scoring system to evaluate the risk of SB occlusion in bifurcation intervention and used as one of the inclusion criteria to select patients with high SB occlusion risk (V-RESOLVE score ≥12). A total of 21 hospitals from 10 provinces in China participated in the present study. 566 patients meeting all inclusion/exclusion criteria are randomised to either intentional strategy group or conventional strategy group. The primary endpoint is SB occlusion (defined as any decrease in thrombolysis in myocardial infarction flow grade or absence of flow in SB after main vessel stenting). All patients are followed up for 12-month postdischarge.

ETHICS AND DISSEMINATION

The protocol has been approved by all local ethics committee. The ethics committee have approved the study protocol, evaluated the risk to benefit ratio, allowed operators with a minimum annual volume of 200 cases to participate in the percutaneous coronary intervention procedure and permitted them to perform both conventional and intentional strategies. Written informed consent would be acquired from all participants. The findings of the trial will be shared by the participant hospitals and disseminated through peer-reviewed journals.

TRIAL REGISTRATION NUMBER

NCT02644434; Pre-results.

Hemodynamics in Coronary Arterial Tree of Serial Stenoses

Serial segmental narrowing frequently occurs in humans, which alters coronary hemodynamics and further affects atherosclerotic progression and plaque formation. The objective of this study was to understand the distribution of hemodynamic parameters in the epicardial left main coronary arterial (LMCA) tree with serial stenoses reconstructed from patient computer tomography angiography (CTA) images. A finite volume method was used in conjunction with the inlet pressure wave and outlet flow resistance. The time-averaged wall shear stress (TAWSS) and oscillatory shear index (OSI) were determined from the flow field. A stenosis at a mother vessel mainly deteriorated the hemodynamics near the bifurcation while a stenosis at a daughter vessel affected the remote downstream bifurcation. In comparison with a single stenosis, serial stenoses increased the peak pressure gradient along the main trunk of the epicardial left anterior descending arterial tree by > 50%. An increased distance between serial stenoses further increased the peak pressure gradient. These findings have important implications on the diagnosis and treatment of serial coronary stenoses.

Predictors for Side Branch Failure During Provisional Strategy of Coronary Intervention for Bifurcation Lesions (from the Korean Bifurcation Registry)

The most favored strategy for bifurcation lesion is stenting main vessel with provisional side branch (SB) stenting. This study was performed to elucidate predictors for SB failure during this provisional strategy. The study population was patients from 16 centers in Korea who underwent drug-eluting stent implantation for bifurcation lesions with provisional strategy (1,219 patients and 1,236 lesions). On multivariate analysis, the independent predictors for SB jailing after main vessel stenting were SB calcification, large SB reference diameter, severe stenosis of SB, and not taking clopidogrel. Regarding SB compromise, however, the independent predictors were true bifurcation lesion and small SB reference diameter, whereas possible predictors were parent vessel thrombus and parent vessel total occlusion. In addition, SB predilation helps us to get favorable SB outcome. The diameter of SB ostium after main vessel stenting became similar between severe SB lesions treated with predilation and mild SB lesions not treated with predilation. In conclusion, SB calcification, less clopidogrel use, large SB reference diameter, and high SB diameter stenosis are independent predictors for SB jailing, and true bifurcation and small SB reference diameter are independent predictors for SB compromise after main vessel stenting.

A Pilot Study on Culottes versus Crossover Single Stenting for True Coronary Bifurcation Lesions

BACKGROUND

The purpose of our study was to compare clinical and angiographic outcomes of planned culottes technique with that of provisional crossover single stenting in the treatment of true coronary bifurcation lesions (CBL) with drug-eluting stent (DES).

METHODS

True CBL patients (n = 104) were randomly assigned to either the provisional stenting of the side branch (crossover group) or the culottes group. Additional side branch (SB) stenting in the crossover group was required if there was thrombolysis in myocardial infarction flow ≤ 1 flow). The primary end point was the occurrence of major adverse cardiac events (MACE) at nine months, including cardiac death, myocardial infarction, target lesion/vessel revascularization and in-stent thrombosis. The secondary end point was angiographic in-segment restenosis at nine months.

RESULTS

The rate of MACE at nine months was similar between the crossover and culottes groups (7.7% vs. 7.7%, p = 1.000). Additional SB stenting in the crossover group was required in 3.8% of patients. There was one procedural occlusion of SB in the crossover group. At nine months, the rate of in-segment restenosis was similar in the parent main vessel (0% vs. 1.9%, p = 1.000), main branch (1.9% vs. 7.7%, p = 0.363) and SB (17.3% vs. 9.6%, p = 0.250) between the crossover and culottes groups, respectively.

CONCLUSIONS

This study demonstrated that there is no significant difference in cumulative MACE or in-segment restenosis between crossover and culottes groups. Larger randomized clinical trials are warranted to re-evaluate the outcomes of the provisional crossover stenting versus the culottes stenting techniques utilizing DES for true CBL.

Results From the International Drug Coated Balloon Registry for the Treatment of Bifurcations. Can a Bifurcation Be Treated Without Stents?

OBJECTIVES

This observational study assessed the 9-month clinical outcomes in patients with coronary bifurcation lesions suitable for drug-coated balloon (DCB) angioplasty. It was the intention to use DCB's without additional stenting (DCB-only strategy) in selected patients for this chosen strategy. Bail-out main branch (MB) and/or side branch (SB) stenting, however, were permissible when flow limiting dissections or excessive recoil occurred.

BACKGROUND

A multitude of interventional strategies have been studied to treat bifurcation lesions. With the availability of DCB angioplasty, investigators have been using this interventional tool with the optional implantation of bare metal stents (BMS).

METHODS

This study is an international, prospective, multicenter registry enrolling patients with coronary bifurcation lesions including a side branch ≥2 mm in diameter. Patients with stable angina and documented ischemia or selected forms of unstable angina due to a culprit bifurcation lesion of any Medina classification type were recruited. The primary endpoint was clinically driven target-lesion revascularization (TLR) at 9 months. Secondary endpoints included 9-month major adverse cardiac events (death, myocardial infarction, or TLR), technical success, in-hospital outcomes and vessel thrombosis rates.

RESULTS

A total 127 patients 66.1 ± 10.1 years of age were enrolled. Demographic characteristics were 80.3% (102/127) male gender, 31.5% (40/127) diabetes, 91.3% (116/127) hypertension, 7.1% (9/127) ST-elevation myocardial infarction (STEMI), and 9.4% (12/127) non ST-elevation myocardial infarction (NSTEMI). The 130 lesions were treated with 184 DCB's and 64 BMS. In 53.8% (70/130) of all lesions the DCB-only strategy could be used while 34.6% (45/130) of lesions had at least 1 stent (BMS) in the main branch, 8.5% (11/130) had at least 1 stent in the side branch and 3.1% (4/130) needed at least 1 stent in the main and side branch. 94.5% patients (121/127) were available for follow-up after 9.8 ± 2.0 months. The TLR rate was 4.6% in the absence of any thrombotic events in the treated vessels whereas the 9-month MACE rate was 6.2%.

CONCLUSION

This observational study suggests that the DCB-only strategy is safe and effective to treat selected bifurcations while benefiting from a shortened dual antiplatelet therapy (DAPT).

The Effects of Side Branch Predilation During Provisional Stenting of Coronary Bifurcation Lesions: A Double-Blind Randomized Controlled Trial

BACKGROUND

There is a paucity of data regarding the role of side branch (SB) predilation during the provisional stenting of bifurcation lesions.

OBJECTIVES

The present study aimed to assess the effects of SB predilation on the outcomes of true bifurcation interventions.

PATIENTS AND METHODS

Sixty patients with true bifurcation lesions according to the Medina classification were included in the study and randomly assigned to receive SB predilation before stenting the main branch (n = 30) or no predilation as the control group (n = 30).

RESULTS

There was a trend toward the higher occurrence of dissection in the predilated ostial lesions of the SB compared to the non-predilated group (16.7% vs. 0, P = 0.07). Performance of the SB predilation was not associated with improved flow of the SB or fewer degrees of ostial stenosis after stenting the main branch, the need to rewire, rewiring time, or the rate of use of the final kissing balloon dilation and double stents procedures.

CONCLUSIONS

Routine predilation of the SB in provisional stenting of true bifurcation lesions seems to be ineffective and might be associated with some undesirable consequences. Still, there are some complex ostial lesions of the SB which could benefit from predilation.

Comparison of failure rates of crossing side branch with pressure vs. coronary guidewire: a meta-analysis

OBJECTIVES

The aim of this study was to compare the failure rates of crossing side branch (SB) with pressure guidewire vs. coronary guidewire after main vessel (MV) stenting in coronary bifurcation lesions (CBL).

BACKGROUND

Percutaneous coronary intervention of CBL is technically difficult. The European Bifurcation Club recommends performing either fractional flow reserve (FFR) estimation of the SB or final kissing balloon inflation (FKBI) after the MV stenting when a significant SB ostial stenosis is present. Even though FFR is recommended in CBL, there is concern about SB crossing with pressure guidewire among interventionists.

MATERIALS AND METHODS

We undertook a comprehensive literature search to identify all relevant studies reporting the failure rates of SB crossing after MV stenting with either pressure or coronary guidewire. A random effects model was used to compare the failure rates between the two approaches.

RESULTS

Our search identified six studies that reported failure rates of SB crossing with a pressure guidewire (n = 648) and 11 studies that reported failure rates of SB crossing with a coronary guide-wire (n = 2601). Estimated pooled failure rate was 3·9% (95% CI: 1·5% to 9·6%) for inability to cross SB with pressure guidewire. Estimated pooled failure rate of SB crossing with coronary guidewire was 3·1% (95% CI: 1·5% to 6·2%). There was no significant difference between the failure rates in the two groups (P = 0·70).

CONCLUSION

The failure rates of SB crossing after MV stenting are low with both pressure and coronary guidewire procedures, with no significant difference between the two approaches.

Safety of hydrophilic guidewires used for side-branch protection during stenting and proximal optimization technique in coronary bifurcation lesions

BACKGROUND AND PROPOSE

In coronary bifurcation lesions (CBL), hydrophilic guidewires used for side-branch (SB) protection can be withdrawn from underneath the stent easier than other wires. However, the safety of which has not been investigated.

METHODS/MATERIALS

We performed scanning electron microscopic (SEM) examination of hydrophilic wires - the Whisper and Runthrough wires - used for SB protection during stenting and proximal optimization technique (POT) in 30 patients with CBL. The distal 15cm of the wire was examined every 1mm by SEM and 4500 segments were analyzed to investigate for wire fracture, polymer shearing (PS), and its correlations with post-stenting creatine kinase (CK)-MB release.

RESULTS

SEM examination showed no evidence for wire fracture. The total area of PS and the largest defect on the wire were significantly larger with the Whisper wire versus the Runthrough wire (0.15±0.04mm² vs. 0.026±0.01mm² and 0.04±0.05mm² vs. 0.01±0.01mm²; P<0.05, respectively). The total length of PS and the longest defect on the wire were significantly longer with the Whisper wire vs. the Runthrough wire (12.1±14.5mm vs. 2.7±3.0mm and 2.9±4.2mm vs. 1.0±1.2mm; P<0.05, respectively), but there were weak correlations between the extents of PS with CK-MB release.

CONCLUSIONS

Hydrophilic guidewires may be safely used for SB protection during stenting and POT in CBLs. The extent of PS was significantly greater with the Whisper wire than with the Runthrough wire, but its correlation with post-stenting CK-MB release was weak.

Impact of bifurcation target lesion on angiographic, electrocardiographic, and clinical outcomes of patients undergoing primary percutaneous coronary intervention (from the Harmonizing Outcomes With Revascularization and Stents in Acute Myocardial Infarction [HORIZONS-AMI] trial)

AIMS

Using the database from the large-scale, prospective, randomised HORIZONS-AMI trial, the authors sought to assess the impact of bifurcation target lesions (BTL) on angiographic, electrocardiographic, and clinical outcomes in patients with ST-segment elevation myocardial infarction (STEMI) undergoing percutaneous coronary intervention (PCI).

METHODS AND RESULTS

In HORIZONS-AMI, bifurcation lesions in which a provisional approach was planned were eligible for enrolment. By angiographic core laboratory assessment of 3,306 patients with STEMI undergoing primary PCI, 333 patients (10%) had ≥1 BTL, and 2,973 patients had no BTL. There were no significant differences in baseline characteristics between the groups, except for lower left ventricular ejection fraction and more frequent left anterior descending infarct artery in the BTL group. BTLs required longer procedural and fluoroscopy times and higher contrast loads, but rates of TIMI 3 flow post PCI were similar in both groups (with vs. without BTL 99% vs. 87%, p=0.25). ST-segment resolution ≥70% by core laboratory analysis was similar in both groups (48% vs. 50%, p=0.47). Importantly, there was no difference between groups in the rate of death (6.1% vs. 6.7%, p=0.72), definite or probable stent thrombosis (4.2% vs. 5.2%, p=0.42), and ischaemic target vessel revascularisation (14.3% vs. 14.0%, p=0.86) during three-year follow-up.

CONCLUSIONS

Although the PCI procedure involving BTL was more complex, the acute results and late outcomes in patients with BTLs were comparable to those in patients without BTLs.

A Novel Tram Stent Method in the Treatment of Coronary Bifurcation Lesions - Finite Element Study

A novel stent was designed for the treatment of coronary bifurcation lesion, and it was investigated for its performance by finite element analysis. This study was performed in search of a novel method of treatment of bifurcation lesion with provisional stenting. A bifurcation model was created with the proximal vessel of 3.2 mm diameter, and the distal vessel after the side branch (2.3 mm) was 2.7 mm. A novel stent was designed with connection links that had a profile of a tram. Laser cutting and shape setting of the stent was performed, and thereafter it was crimped and deployed over a balloon. The contact pressure, stresses on the arterial wall, stresses on the stent, the maximal principal log strain of the main artery and the side-branch were studied. The study was performed in Abaqus, Simulia. The stresses on the main branch and the distal branch were minimally increased after deployment of this novel stent. The side branch was preserved, and the stresses on the side branch were lesser; and at the confluence of bifurcation on either side of the side branch origin the von-Mises stress was marginally increased. The stresses and strain at the bifurcation were significantly lesser than the stresses and strain of the currently existing techniques used in the treatment of bifurcation lesions though the study was primarily focused only on the utility of the new technology. There is a potential for a novel Tram-stent method in the treatment of coronary bifurcation lesions.

The story of plaque shift and carina shift

Side branch (SB) occlusion is one of the most serious complications of main vessel (MV) stenting. Although plaque shift has been considered the major mechanism of SB occlusion, recent studies have suggested carina shift to be the more important cause. Considering the recent pressure wire as well as intravascular ultrasonography studies, the relationship between carina shift and plaque shift in SB occlusion can be described as follows. The anatomical compromise of the SB after MV stenting is not as functionally significant as it appears, because it is mostly explained by carina shift, which is not the major cause of functional compromise. Superimposition of plaque shift over carina shift appears to be the mechanism of haemodynamically significant SB stenosis. Plaque is shifted mostly from the proximal MV, which explains why the plaque burden of the proximal MV is a significant risk factor of SB functional compromise or occlusion.