In vivo assessment of bifurcation optimal viewing angles and bifurcation angles by three-dimensional (3D) quantitative coronary angiography

Multislice computerized tomography coronary angiography can be a comparable tool to intravascular ultrasound in evaluating "true" coronary artery bifurcations

Aim

Coronary bifurcation atherosclerosis depends on its angles, flow, and extensive branching. We investigate the ability of CT coronary angiography (CTCA) to determine atherosclerotic plaque characteristics of "true" bifurcation compared with intravascular ultrasound (IVUS) and the influence on side branch (SB) fate after percutaneous coronary intervention (PCI).

Methods and results

The study included 70 patients with 72 "true" bifurcations. Most of the bifurcations were in the left anterior descending-diagonal (Dg) territory [50 out of 72 (69.4%)]. Longitudinal plaque evaluation at the polygon of confluence [carina and 5 mm proximal and distal in the main branch (MB)] showed that carina side MB and SB plaque had occurred with the lowest incidence with fibro-lipid structure (115 ± 63 HU and 89 ± 73 HU, p < 0.001 for all). Bland-Altman analysis showed a discrepancy in measuring mainly the lumen area between CTCA and IVUS in proximal MB [lumen 5.10, 95% CI (95% confidence interval, 4.53-5.68) mm2, p < 0.001; vessel -1.42, 95% CI (-2.63 to -0.21) mm2, p = 0.023], carina MB [lumen 3.74, 95% CI (3.37-4.10) mm2, p < 0.001; vessel -0.48, 95% CI (-1.45 to 0.48) mm2, p = 0.322], and distal MB [lumen 4.72, 95% CI (4.27-5.18) mm2, p < 0.001; vessel 0.62, 95% CI (-0.53 to 1.77) mm2, p = 0.283]. A significant correlation existed between average plaque density on CTCA with a percentage of calcified plaque on IVUS tissue characterization (proximal r = 0.307/p = 0.024, carina 0.469/0.008, distal 0.339/0.024, minimal lumen diameter 0.318/0.020). Circumferential plaque in the proximal MB segment remained an independent predictor of SB compromise [OR 3.962 (95% CI 1.170-13.418)].

Conclusion

Detection and characterization of atherosclerotic plaque by CTCA in non-left main "true" coronary bifurcations can provide useful information about bifurcation anatomy and plaque distribution that can predict outcomes after provisional stenting, thus guiding the interventional strategy to bifurcation PCI.

OCT or Angiography Guidance for PCI in Complex Bifurcation Lesions

BACKGROUND

Imaging-guided percutaneous coronary intervention (PCI) is associated with better clinical outcomes than angiography-guided PCI. Whether routine optical coherence tomography (OCT) guidance in PCI of lesions involving coronary-artery branch points (bifurcations) improves clinical outcomes as compared with angiographic guidance is uncertain.

METHODS

We conducted a multicenter, randomized, open-label trial at 38 centers in Europe. Patients with a clinical indication for PCI and a complex bifurcation lesion identified by means of coronary angiography were randomly assigned in a 1:1 ratio to OCT-guided PCI or angiography-guided PCI. The primary end point was a composite of major adverse cardiac events (MACE), defined as death from a cardiac cause, target-lesion myocardial infarction, or ischemia-driven target-lesion revascularization at a median follow-up of 2 years.

RESULTS

We assigned 1201 patients to OCT-guided PCI (600 patients) or angiography-guided PCI (601 patients). A total of 111 patients (18.5%) in the OCT-guided PCI group and 116 (19.3%) in the angiography-guided PCI group had a bifurcation lesion involving the left main coronary artery. At 2 years, a primary end-point event had occurred in 59 patients (10.1%) in the OCT-guided PCI group and in 83 patients (14.1%) in the angiography-guided PCI group (hazard ratio, 0.70; 95% confidence interval, 0.50 to 0.98; P = 0.035). Procedure-related complications occurred in 41 patients (6.8%) in the OCT-guided PCI group and 34 patients (5.7%) in the angiography-guided PCI group.

CONCLUSIONS

Among patients with complex coronary-artery bifurcation lesions, OCT-guided PCI was associated with a lower incidence of MACE at 2 years than angiography-guided PCI. (Funded by Abbott Vascular and others; OCTOBER ClinicalTrials.gov number, NCT03171311.).

Importance of optimal rewiring guided by 3-dimensional optical frequency domain imaging during double-kissing culotte stenting demonstrated through a novel bench model

The usefulness of optical frequency domain imaging (OFDI) guidance on two-stenting at left main bifurcation has not been evaluated. Here, we used a novel bench model to investigate whether pre-defined optimal rewiring with OFDI-guidance decreases acute incomplete stent apposition (ISA) at the left main bifurcation segment. A novel bench simulation system was developed to simulate the foreshortening and overlapping of daughter vessels as well as left main bifurcation motion under fluoroscopy. Double-kissing (DK) culotte stenting was performed using the novel bench model under fluoroscopy with or without OFDI-guidance. In the OFDI-guidance group, if the guidewire did not pass through the pre-defined optimal cell according to the 3-dimensional OFDI, additional attempts of rewiring into the jailed side branch were performed. The success rate of optimal jailed side branch rewiring after implantation of the first and second stent under OFDI-guidance was significantly higher than that under only angio-guidance. After completion of the DK-culotte stenting, the incidence and volume of ISA at the bifurcation segment in the OFDI-guidance group was significantly lower than that in the angio-guidance group. Online 3-dimensional OFDI-guided DK-culotte stenting according to a pre-defined optimal rewiring point might be superior to only angio-guided rewiring for reducing ISA at the bifurcation.

Impact of Coronary Microvascular Dysfunction on Myocardial Strain in Patients with Heart Failure and Preserved Ejection Fraction

Background

This research aimed to evaluate the role of coronary microvascular dysfunction in alteration of left ventricular (LV) myocardial deformation.

Materials and Methods

This observational study involved 50 patients with LV ejection fraction (LVEF) >50% and coronary microvascular dysfunction (diagnosed by coronary angiography). TIMI frame count (TFC) was calculated for each patient. They were classified into 2 groups: 30 patients with heart failure and preserved ejection fraction (HFpEF) (cases group) and 20 patients without HF (control group). Speckle tracking echocardiography was used to evaluate LV deformation.

Results

The mean age of the studied patients was 58.8 ± 8 years. The frequency of diabetes mellitus, hypertension, and dyslipidemia were significantly higher in cases than controls. Cases had significant higher BMI (30 ± 4.48 vs. 27.3 ± 3.94 kg/m2, P=0.029). The total TFC in cases was 97.1 ± 22.9 and in controls was 79 ± 18.5, and this difference was statistically significant (P=0.005). Significantly decreased LV global strain was observed in HFpEF cases than in controls (-17.6 ± 2.14 % versus -19.5 ± 1.98%, P < 0.001). In cases with a higher TFC, the LV global strain decrease was more pronounced. There was a significant correlation between the LV global strain and total TFC (r=-0.470 and P=0.009).

Conclusion

Patients with HFpEF exhibited higher total TFC reflecting more affected coronary microvasculature. Those patients had reduced LV global strain. Coronary microvascular dysfunction probably leads to alteration of myocardial performance.

Association between bifurcation angle of the left main coronary artery and severity of stenosis of the proximal left anterior descending artery

AIM

The aim of this study was to evaluate the association between the left main coronary artery (LM) bifurcation angle and the severity of the proximal left anterior descending coronary artery (LAD) stenosis.

METHODS

Two hundred patients with suspected coronary artery disease who had coronary angiography were included in this observational study. The severity of coronary artery stenosis was analysed using quantitative coronary angiography software (QCA analysis). The LM-LAD and LAD-left circumflex artery (LCX) angles were measured using software (IC MEASURE) in two-dimensional axial images.

RESULTS

The patients were divided into two groups. The first group included 100 patients with significant proximal LAD stenosis (≥ 50%) and the second, those with LAD stenosis < 50% (100 patients). Patients with significant proximal LAD stenosis were older and had a higher frequency of diabetes mellitus, and higher serum creatinine and low-density lipoprotein levels than those with non-significant LAD stenosis. The LM-LAD and LAD-LCX angles in patients with significant proximal LAD stenosis were wider than in patients with non-significant LAD stenosis (p < 0.001). The cut-off value of 42° of the LM-LAD angle had a sensitivity of 73% and specificity of 70% to predict significant proximal LAD stenosis. The cut-off value of 68° of the LAD-LCX angle had a sensitivity of 68% and specificity of 62% to predict significant proximal LAD disease. In a multivariate logistic regression analysis, LM-LAD and LAD-LCX angles were independent factors for the development of significant proximal LAD stenosis.

CONCLUSIONS

Wider LM-LAD and LAD-LCX angles were associated with the severity of proximal LAD disease. Preventative measures and close follow up are needed in such cases to improve their cardiovascular outcome.

Crush techniques for percutaneous coronary intervention of bifurcation lesions

Percutaneous coronary intervention (PCI) of coronary artery bifurcation lesions entails technical challenges and carries a higher risk of adverse events on follow-up, driven by repeat revascularisation and stent thrombosis. While most bifurcations can be tackled with a provisional (single-stent) approach, more complex lesions involving both branches (true bifurcation lesions) require a two-stent approach. In the latter context, several techniques have been proposed. Among them, the crush technique has dramatically evolved in recent years, and its more recent iterations have been shown to provide excellent and durable results, both for left main and non-left main bifurcations. The aim of the present work is to discuss the technical aspects and outcomes of the variants of the crush technique from the first description in the early 2000s to the present day.

Coronary CT Angiography to Guide Percutaneous Coronary Intervention

Coronary CT angiography (CCTA) has emerged as a powerful noninvasive tool for characterizing the presence, extent, and severity of coronary artery disease (CAD) in patients with stable angina. Recent technological advancements in CT scanner hardware and software have augmented the rich information that can be derived from a single CCTA study. Beyond merely identifying the presence of CAD and assessing stenosis severity, CCTA now allows for the identification and characterization of plaques, lesion length, and fluoroscopic angle optimization, as well as enables the assessment of the physiologic extent of stenosis through CT-derived fractional flow reserve, and may even allow for the prediction of the response to revascularization. These and other features make CCTA capable of not only guiding invasive coronary angiography referral, but also give it the unique ability to help plan coronary intervention. This review summarizes current and future applications of CCTA in procedural planning for percutaneous coronary intervention, provides rationale for wider integration of CCTA in the workflow of the interventional cardiologist, and details how CCTA may help improve patient care and clinical outcomes. Keywords: CT Angiography © RSNA, 2022.

Efficacy of coronary imaging on bifurcation intervention

During the coronary bifurcation intervention procedure, imaging including intravascular ultrasound and optical coherence tomography is essential to provide precise anatomy of the lesion and morphological information. This consensus document between the Korean Bifurcation Club and the Japanese Bifurcation Club summarizes practical guidelines and current evidences on lesion assessment, device selection, procedural guidance, and the optimization of bifurcation intervention by the imaging.

Relationship between neointimal strut bridge and jailed side-branch ostial area

BACKGROUND

Our study analyzed the relationship between the neointimal strut bridge and jailed side-branch (SB) ostial area in patients with coronary heart disease (CHD) who had a single drug-eluting stent (DES) crossover of the left anterior descending coronary artery (LAD)/diagonal branch (D) bifurcation.

PATIENTS AND METHODS

A total of 64 CHD patients with an LAD/D bifurcation treated by optical coherence tomography (OCT)-guided single-DES implantation and followed up at 1 year after primary percutaneous intervention (pPCI) were enrolled in our study. According to the two-dimensional OCT results, patients were divided into a non-neointimal bridge group (n = 44) and a neointimal bridge group (n = 20). Basic clinical, angiographic, 2D and 3D OCT, and DES results were analyzed.

RESULTS

The blood lipid levels of the two groups after the 1‑year follow-up were lower than the levels 1 year earlier (p < 0.05). There was a notable decrease in the SB ostial minimum lumen diameter and area directly after pPCI vs. before pPCI in both groups. The diameter stenosis directly after pPCI showed a clear increase compared with the pre-pPCI value in both groups (p < 0.05 or p < 0.01, respectively). The strut distance of the neointimal bridges in the neointimal bridge group was greater than in the non-neointimal bridge group (p < 0.05). A clearly short strut distance of the neointimal bridge was observed compared with the strut distance of the non-neointimal bridge in the neointimal bridge group (p < 0.05). A larger neointimal bridge area and a smaller SB ostial area were found in the neointimal bridge group compared with the non-neointimal bridge group (p < 0.05 or p < 0.01, respectively).

CONCLUSION

A short strut distance facilitated formation of a neointimal bridge, which significantly influenced the SB ostial area after single crossover stenting of the SB orifice at the 1‑year follow-up.

Rational and design of the European randomized Optical Coherence Tomography Optimized Bifurcation Event Reduction Trial (OCTOBER)

Background

Percutaneous coronary intervention in complex bifurcation lesions is prone to suboptimal implantation results and is associated with increased risk of subsequent clinical events. Angiographic ambiguity is high during bifurcation stenting, but it is unknown if procedural guidance by intravascular optical coherence tomography (OCT) improves clinical outcome.

Methods and Design

OCTOBER is a randomized, investigator-initiated, multicenter trial aimed to show superiority of OCT-guided stent implantation compared to standard angiographic-guided implantation in bifurcation lesions. The primary outcome measure is a 2-year composite end point of cardiac death, target lesion myocardial infarction, and ischemia-driven target lesion revascularization. The calculated sample size is 1,200 patients in total, and allocation is 1:1. Eligible patients have stable or unstable angina pectoris or stabilized non–ST elevation myocardial infarction, and a coronary bifurcation lesion with significant main vessel stenosis and more than 50 % stenosis in a side branch with a reference diameter ≥2.5mm. Treatment is performed by the provisional side branch stenting technique or 2-stent techniques, and the systematic OCT guiding protocol is aimed to evaluate (1) plaque preparation, (2) lesion length, (3) segmental reference sizes, (4) lesion coverage, (5) stent expansion, (6) malapposition, (7) wire positions, and (8) ostial results.

Implications

A positive outcome of the OCTOBER trial may establish OCT as a routine tool for optimization of complex percutaneous coronary intervention, whereas a negative result would indicate that OCT remains a tool for ad hoc evaluation in selected cases.

Contemporary techniques in percutaneous coronary intervention for bifurcation lesions

INTRODUCTION

Treatment of coronary bifurcation lesions with contemporary state-of-the-art percutaneous coronary intervention (PCI) is still associated with higher rate of adverse cardiovascular events compared to non-bifurcation lesions. Bench testing and virtual computer modeling have increased our understanding of bifurcation PCI guiding refinement in bifurcation techniques. New insights on bifurcation PCI have the potential to further improve clinical outcomes in patients presenting with bifurcation lesions. Areas covered: The present manuscript aims to review the methods for bifurcation lesion assessment and treatment strategy step by step supported on bench and clinical evidence. Expert commentary: Invasive pressure-wire evaluation is essential to determine the appropriateness of bifurcation PCI, particularly in intermediate coronary stenosis. Treatment strategy relies on four parameters: diameters of the three segments of the bifurcation; lesion length and plaque distribution; and bifurcation angle. The optimal technique for bifurcation PCI is still debated, an individualized approach with an initial provisional side branch stenting strategy seems to be suitable in the 75 to 95% of patients. For more complex bifurcations, two-stent techniques may be required with increasing evidence supporting the usefulness of the double kissing balloon crush (DK-crush) technique.

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.

Association of stent-induced changes in coronary geometry with late stent failure: Insights from three-dimensional quantitative coronary angiographic analysis

BACKGROUND

The relationship between vessel angulation and large changes in vessel geometry after stent implantation and the occurrence of stent failure still remains unclear. We sought to investigate the association of the change in the coronary bending angle after stenting and the risk for late stent failure by three-dimensional quantitative coronary angiography (3D QCA).

METHODS

The bending angle in coronary lesions that presented with late stent failure and those without stent failure was computed during the cardiac cycle, before and after stenting using a recently developed 3D QCA software.

RESULTS

A total of 40 lesions with stent failure (cases) were successfully matched to 47 lesions without stent failure (controls).The mean duration to follow-up coronary angiography was 1,011 days in cases and 1,109 days in the control group (P = 0.14). In stent failure, the systolic bending angle after stenting was smaller (14.45° [12.18, 17.68] versus 18.20° [14.00, 20.30], P = 0.01), while the stent-induced change in systolic bending angle was significantly larger (4.15° [1.13, 7.20] versus 1.80° [-1.90, 4.40], P = 0.004). Multivariable logistic regression analysis suggested that systolic bending angle after stenting (odds ratio: 0.88; 95% CI: 0.79-0.99; P = 0.03), and decrease in systolic bending angle after stenting (odds ratio: 1.13; 95% CI: 1.02-1.26; P = 0.03) were predictors of stent failure.

CONCLUSIONS

Our study suggests that a change in the natural tortuous course of the coronaries by stent implantation with the decrease in coronary bending angle is a potentially major contributor in stent failure.

In vitro validation of coronary CT angiography for the evaluation of complex lesions

AIMS

The aim of this study was to assess in vitro the diagnostic accuracy of computed tomography angiography (CTA) for the evaluation of complex coronary lesions.

METHODS AND RESULTS

Five Plexiglas phantoms with three bifurcation lesions each were designed to mimic the anatomic variations and fractal phenomena of the coronary tree. In addition, luminal stenoses were scaled up with increases of 10% from 40% to 80%, corresponding to luminal areas ranging from 3.0 mm2 to 0.22 mm2. Third-generation dual-source computed tomography was used. Automated quantitative CTA analysis was performed according to the bifurcation segment model. The primary objective was to determine the diagnostic accuracy of quantitative CTA in assessing bifurcation lesions with the phantoms as a reference. The accuracy of CTA for the assessment of minimal luminal diameter was -0.07 mm (limits of agreement -0.75 to 0.61), for reference vessel diameter 0.19 mm (limits of agreement -0.25 to 0.63) and diameter stenosis 8.2% (limits of agreement -13.2 to 29.5) with no difference regarding the location within the bifurcation (i.e., proximal and distal main vessel and side branch). In stenosis with minimal luminal diameter ≥1 mm, CTA overestimated the lesion severity (bias 0.19 mm, limits of agreement -0.09 to 0.47), whereas in lesions with severe stenosis and minimal luminal diameter ≤1 mm, CTA underestimated the lesion severity (bias -0.48 mm, limits of agreement -0.55 to -0.41). CTA was able to identify the contrast-filled lumen in all degrees of lesion severity.

CONCLUSIONS

In vitro, CTA is accurate for the evaluation of bifurcation lesions. CTA was able to distinguish contrast-filled lumen even in severe obstructive lesions. These findings require further validation in the clinical setting.

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.

Serial changes in the three-dimensional aspect of the side-branch ostium jailed by a drug-eluting stent assessed by optical coherence tomography

The present study investigated serial changes in the three-dimensional (3D) aspect of the jailed side-branch (SB) ostium. We evaluated 32 patients who underwent examination with optical coherence tomography (OCT) both at baseline and at follow-up. After reconstruction of the 3D images, we classified the configuration of overhanging struts at the SB orifice into three groups according to the 3D aspect of the jailing configuration. The number of compartments divided by the stent strut was counted. The side-branch flow area (SBFA), i.e., the area of the SB ostium except for jailing struts, was measured by cut-plane analysis. Forty-eight SBs of 25 patients were analyzed. Thirteen SBs were classified as the No-jail type (N-type), 19 as the Simple-jail type (S-type; no longitudinal link at the carina), and 16 as the Complex-jail type (C-type; had a link at the carina). In the N-type, the SBFA was significantly increased at follow-up (P = 0.018). In the C-type, the SBFA was significantly decreased at follow-up (P = 0.002). Percent reduction of SBFA in the C-type group was significantly greater than that in the N-type or S-type groups (S-type vs. C-type P = 0.002, N-type vs. C-type P < 0.001). 3D-OCT images showed that some of the compartments were filled with tissue. The number of compartments was significantly decreased at follow-up (P < 0.001). In the C-type group, the SBFA was significantly decreased and small compartments were filled with tissue. These findings suggest that stent jail complexity is associated with the progression of SB ostial stenosis.

Relationship between left coronary artery bifurcation angle and restenosis after stenting of the proximal left anterior descending artery

INTRODUCTION

Restenosis after a percutaneous coronary intervention for proximal left anterior descending (pLAD) coronary artery disease remains a clinical challenge. However, the relationship between the left main trunk (LMT)/LAD bifurcation angle and the pLAD artery restenosis is unclear. This study examined the relationship between the LMT-LAD bifurcation angle and restenosis after stent implantation for pLAD disease.

METHODS

We analysed the data of 177 consecutive patients who underwent stent implantation for pLAD disease, followed by coronary angiography between December 2008 and September 2013. The LMT-LAD bifurcation angle was measured in the left or the right anterior oblique caudal (CAU) angiographic view.

RESULTS AND DISCUSSION

Out of 177 patients, 12 developed in-stent restenosis and 21 developed in-segment restenosis. The mean angle in patients with in-stent restenosis (52.2°±14.5°) in the left anterior oblique CAU view was significantly larger than that in patients without restenosis (32.0°±18.1°; P<0.001). The LMT-LAD angle in the right anterior oblique CAU view was significantly larger in patients with in-segment restenosis (27.3°±14.3°) than in patients without restenosis (17.5°±10.1°; P<0.001). Moreover, by multivariate analysis, the LMT-LAD angle was an independent predictor of in-stent and in-segment restenosis, after adjustment for significant confounders such as diabetes, hypertension, dyslipidaemia, final minimum lesion diameter and lesion length.

CONCLUSION

This study suggests that a wide LMT-LAD angle is a predictor of restenosis after stent implantation for pLAD artery disease.

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.

Percutaneous Coronary Intervention for Bifurcation Lesions

This article summarizes treatment alternatives for coronary bifurcation lesions. It also reviews current definitions and classifications pertaining to bifurcation lesions and provides an overview of the impact of bifurcation lesions on clinical outcomes.

Plaque morphology predictors of side branch occlusion after provisional stenting in coronary bifurcation lesion: Results of optical coherence tomography bifurcation study (ORBID)

OBJECTIVES

The aim of this study was to identify the predictors of side branch (SB) ostial stenosis developed after provisional stenting of the main vessel (MV) using optical coherence tomography (OCT).

BACKGROUND

Provisional stenting remains the main approach to treatment of bifurcation lesions; however, it may result in the narrowing of SB ostium. There is little information about underlying plaque morphology of the MV lesion and its potential impact on the SB after provisional stenting.

METHODS

Patients with stable coronary disease with angiographic MV lesion not involving SB were included in a prospective single center study. The primary outcome was significant SB ostium stenosis (SBOS), defined as residual stenosis of >50% after MV stenting.

RESULTS

Thirty bifurcation lesions in 30 patients were analyzed in the study. Poststenting significant SBOS was observed in 30% of patients. The MV lesions with SBOS > 50% were characterized by a higher prevalence of lipid rich plaques (100 vs. 64%, p = 0.040) and spotty calcifications (60 vs. 0%, p = 0.005). Maximal lipid arcs were greater (257° vs. 132°, p = 0.001) and lipid volume index was higher (1380 vs. 574, p = 0.012) in the SBOS >50% group. Multivariate logistic regression analysis identified maximal lipid arc (odds ratio (OR): 1.014, p = 0.038) and the presence of lipid plaque contralateral to SB ostium (OR: 8.14, p = 0.046) before stenting as independent predictors of significant SBOS after PCI.

CONCLUSIONS

High lipid content of the MV lesion and a contralateral location of lipid in the bifurcation area may contribute to SBOS after provisional stenting. © 2016 Wiley Periodicals, Inc.

The impact of scaled boundary conditions on wall shear stress computations in atherosclerotic human coronary bifurcations

The aim of this study was to determine if reliable patient-specific wall shear stress (WSS) can be computed when diameter-based scaling laws are used to impose the boundary conditions for computational fluid dynamics. This study focused on mildly diseased human coronary bifurcations since they are predilection sites for atherosclerosis. Eight patients scheduled for percutaneous coronary intervention were imaged with angiography. The velocity proximal and distal of a bifurcation was acquired with intravascular Doppler measurements. These measurements were used for inflow and outflow boundary conditions for the first set of WSS computations. For the second set of computations, absolute inflow and outflow ratios were derived from geometry-based scaling laws based on angiography data. Normalized WSS maps per segment were obtained by dividing the absolute WSS by the mean WSS value. Absolute and normalized WSS maps from the measured-approach and the scaled-approach were compared. A reasonable agreement was found between the measured and scaled inflows, with a median difference of 0.08 ml/s [-0.01; 0.20]. The measured and the scaled outflow ratios showed a good agreement: 1.5 percentage points [-19.0; 4.5]. Absolute WSS maps were sensitive to the inflow and outflow variations, and relatively large differences between the two approaches were observed. For normalized WSS maps, the results for the two approaches were equivalent. This study showed that normalized WSS can be obtained from angiography data alone by applying diameter-based scaling laws to define the boundary conditions. Caution should be taken when absolute WSS is assessed from computations using scaled boundary conditions.

Dedicated stents for distal left main stenting

Left main (LM) coronary bifurcation lesions have different anatomic features from non-LM bifurcation lesions. Dedicated bifurcation devices might facilitate percutaneous coronary intervention (PCI) of LM bifurcations and improve procedural and clinical outcomes. In this review we will discuss the available clinical data on dedicated bifurcation devices for the treatment of LM bifurcation lesions. Furthermore, we will try to discuss all the theoretical advantages and potential drawbacks of these devices in terms of their use in the LM.

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.

Three-dimensional virtual surgery models for percutaneous coronary intervention (PCI) optimization strategies

Percutaneous coronary intervention (PCI), especially coronary stent implantation, has been shown to be an effective treatment for coronary artery disease. However, in-stent restenosis is one of the longstanding unsolvable problems following PCI. Although stents implanted inside narrowed vessels recover normal flux of blood flows, they instantaneously change the wall shear stress (WSS) distribution on the vessel surface. Improper stent implantation positions bring high possibilities of restenosis as it enlarges the low WSS regions and subsequently stimulates more epithelial cell outgrowth on vessel walls. To optimize the stent position for lowering the risk of restenosis, we successfully established a digital three-dimensional (3-D) model based on a real clinical coronary artery and analysed the optimal stenting strategies by computational simulation. Via microfabrication and 3-D printing technology, the digital model was also converted into in vitro microfluidic models with 3-D micro channels. Simultaneously, physicians placed real stents inside them; i.e., they performed “virtual surgeries”. The hydrodynamic experimental results showed that the microfluidic models highly inosculated the simulations. Therefore, our study not only demonstrated that the half-cross stenting strategy could maximally reduce restenosis risks but also indicated that 3-D printing combined with clinical image reconstruction is a promising method for future angiocardiopathy research.

Three-year clinical outcome of patients with bifurcation treatment with second-generation Resolute and Xience V stents in the randomized TWENTE trial

BACKGROUND

Only limited data from large randomized clinical trials have been published on the long-term performance of second-generation drug-eluting stents in bifurcation lesions.

METHODS

We investigated in patients in the randomized TWENTE trial the long-term safety and efficacy of treating bifurcation lesions with 2 widely applied second-generation drug-eluting stents, the zotarolimus-eluting Resolute stent (Medtronic Inc, Santa Rosa, CA) and the everolimus-eluting Xience V stent (Abbott Vascular, Santa Clara, CA). Three-year follow-up was available in 99.3%. Patients were categorized into treatment for ≥1 bifurcation lesion versus treatment for nonbifurcation lesions only.

RESULTS

Among the 1,391 patients of the TWENTE trial, 362 (26%) were treated for bifurcation lesions. At 3-year follow-up, target-vessel failure did not differ between patients treated for bifurcation versus nonbifurcation lesions (13.1% vs 12.6%; P = .84), whereas the periprocedural myocardial infarction rate was higher in patients with bifurcation lesions (6.9% vs 3.1%; P < .01). Of the 362 patients with bifurcation lesion treatment, 179 (49.4%) were treated with Resolute and 183 (50.6%) with Xience V. There was no significant difference in target-vessel failure between the Resolute and Xience V groups with bifurcation treatment (13.6% vs 12.6%; P = .78), and their incidence of definite-or-probable stent thrombosis was low and similar (1.1% vs 0.5%, respectively; P = .62).

CONCLUSION

Despite a significant difference in periprocedural myocardial infarction, 3-year clinical outcome after implantation of second-generation stents was favorable and similar for patients with and without bifurcation lesions. In addition, we observed no difference in long-term clinical outcome after bifurcation lesion treatment with Resolute and Xience V stents.

Percutaneous coronary intervention for coronary bifurcation disease: consensus from the first 10 years of the European Bifurcation Club meetings

The European Bifurcation Club (EBC) is an independent, non-political and informal "think tank" of scientists with a particular interest in clinical, technical and fundamental aspects of the management of coronary artery bifurcation disease. Bifurcations account for 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 is, despite a fast growing scientific literature, still the subject of considerable debate, one of the main concerns being the potential increased risk of late stent thrombosis associated with treatment complexity. The EBC was initiated in 2004 and aims to facilitate an exchange of ideas on 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 opinion of interventional cardiologists with the opinion of a large variety of other scientists on bifurcation management. This year the EBC celebrates its 10-year anniversary. This consensus document represents the summary of the consensus from the last ten years of the annual EBC meetings.

A novel method to assess coronary artery bifurcations by OCT: cut-plane analysis for side-branch ostial assessment from a main-vessel pullback

AIMS

In coronary bifurcations assessment, evaluation of side-branch (SB) ostia by an optical coherence tomography (OCT) pullback performed in the main branch (MB) could speed up lesion evaluation and minimize contrast volume. Dedicated software that reconstructs the cross-sections perpendicular to the SB centreline could improve this assessment. We aimed to validate a new method for assessing the SB ostium from an OCT pullback performed in the MB.

METHODS AND RESULTS

Thirty-one sets of frequency-domain OCT pullbacks from 28 patients, both from the MB and the SB of a coronary artery bifurcation were analysed. Measurements of the SB ostium from the SB pullback were used as a reference. Measurements of the SB ostium from the MB pullback were then performed in a laboratory setting by (i) conventional analysis and (ii) cut-plane analysis, and the measurement error for each analysis was estimated. Correlations of SB ostium measurements acquired from the MB pullback in comparison with reference measurements acquired from the SB pullback were higher with cut-plane analysis compared with conventional analysis, albeit not reaching statistical significance (area: rcut-plane = 0.927 vs. rconventional = 0.870, P = 0.256; mean diameter: rcut-plane = 0.918 vs. rconventional = 0.788, P = 0.056; minimum diameter: rcut-plane = 0.841 vs. rconventional = 0.812, P = 0.734; maximum diameter: rcut-plane = 0.770 vs. rconventional = 0.635, P = 0.316). Cut-plane analysis was associated with lower absolute error than conventional analysis (area: 0.56 ± 0.45, vs. 1.50 ± 1.31 mm(2), P < 0.001; mean diameter: 0.18 ± 0.14 vs. 0.44 ± 0.30 mm, P < 0.001).

CONCLUSION

Measurements of SB ostium performed in a laboratory setting by cut-plane analysis of an OCT pullback of the main branch have high correlation with reference measurements performed in a SB OCT pullback and lower error compared with conventional analysis.

Exploring coronary atherosclerosis with intravascular imaging

Coronary angiography has been widely used for five decades to evaluate a range of vascular pathologies and triage patients to therapeutic interventions. The inability to directly visualize the artery wall with conventional angiographic techniques has stimulated development of a number of intravascular imaging modalities. These approaches have the potential to provide a more comprehensive characterization of the burden, composition and functionality of atherosclerotic plaque, neointimal hyperplasia and allograft vasculopathy that develop within coronary arteries. The ability to use these modalities in vivo and in a serial fashion has provided a greater insight into the factors that underlie the disease process and guide therapeutic interventions.

In vivo comparison of arterial lumen dimensions assessed by co-registered three-dimensional (3D) quantitative coronary angiography, intravascular ultrasound and optical coherence tomography

This study sought to compare lumen dimensions as assessed by 3D quantitative coronary angiography (QCA) and by intravascular ultrasound (IVUS) or optical coherence tomography (OCT), and to assess the association of the discrepancy with vessel curvature. Coronary lumen dimensions often show discrepancies when assessed by X-ray angiography and by IVUS or OCT. One source of error concerns a possible mismatch in the selection of corresponding regions for the comparison. Therefore, we developed a novel, real-time co-registration approach to guarantee the point-to-point correspondence between the X-ray, IVUS and OCT images. A total of 74 patients with indication for cardiac catheterization were retrospectively included. Lumen morphometry was performed by 3D QCA and IVUS or OCT. For quantitative analysis, a novel, dedicated approach for co-registration and lumen detection was employed allowing for assessment of lumen size at multiple positions along the vessel. Vessel curvature was automatically calculated from the 3D arterial vessel centerline. Comparison of 3D QCA and IVUS was performed in 519 distinct positions in 40 vessels. Correlations were r = 0.761, r = 0.790, and r = 0.799 for short diameter (SD), long diameter (LD), and area, respectively. Lumen sizes were larger by IVUS (P < 0.001): SD, 2.51 ± 0.58 mm versus 2.34 ± 0.56 mm; LD, 3.02 ± 0.62 mm versus 2.63 ± 0.58 mm; Area, 6.29 ± 2.77 mm² versus 5.08 ± 2.34 mm². Comparison of 3D QCA and OCT was performed in 541 distinct positions in 40 vessels. Correlations were r = 0.880, r = 0.881, and r = 0.897 for SD, LD, and area, respectively. Lumen sizes were larger by OCT (P < 0.001): SD, 2.70 ± 0.65 mm versus 2.57 ± 0.61 mm; LD, 3.11 ± 0.72 mm versus 2.80 ± 0.62 mm; Area 7.01 ± 3.28 mm² versus 5.93 ± 2.66 mm². The vessel-based discrepancy between 3D QCA and IVUS or OCT long diameters increased with increasing vessel curvature. In conclusion, our comparison of co-registered 3D QCA and invasive imaging data suggests a bias towards larger lumen dimensions by IVUS and by OCT, which was more pronounced in larger and tortuous vessels.