Frequency-domain optical coherence tomography assessment of unprotected left main coronary artery disease-a comparison with intravascular ultrasound

The role of optical coherence tomography in guiding percutaneous coronary interventions: is left main the final challenge?

Left main (LM) coronary artery disease is a high-risk lesion subset, with important prognostic implications for the patients. Recent advances in the field of interventional cardiology have narrowed the gap between surgical and percutaneous approach of this complex lesion setting. However, the rate of repeat revascularization remains higher in the case of percutaneous coronary intervention (PCI) on long-term follow-up. As such, the need for better stent optimization strategies has led to the development of intravascular imaging techniques, represented mainly by intravascular ultrasound (IVUS) and optical coherence tomography (OCT). These techniques are both able to provide excellent pre- and post-PCI guidance. While IVUS is an established modality in optimizing LM PCI, and is recommended by international revascularization guidelines, data and experience on the use of OCT are still limited. This review paper deeply analyzes the current role of OCT imaging in the setting of LM disease, particularly focusing on its utility in assessing plaque morphology and distribution, vessel dimensions and proper stent sizing, analyzing mechanisms of stent failure such as malapposition and underexpansion, guiding bifurcation stenting, as well as offering a direct comparison with IVUS in this critical clinical scenario, based on the most recent available data.

Optical Coherence Tomography Predictors of SIde Branch REstenosis after unprotected Left Main bifurcation angioplasty using double kissing crush technique (OP-SIBRE LM Study)

BACKGROUND

Among the two stent strategies, contemporary evidence favors double kissing crush technique (DKC) for complex unprotected distal left main bifurcation (UdLMB) lesions. However one of the major challenges to these lesions is side branch (SB) restenosis.

AIMS

Our aim was to identify optical coherence tomographic (OCT) characteristics that may predict SB restenosis (SBR) after UdLMB angioplasty using DKC technique.

METHODS

This was a single-center, retrospective study that included 60 patients with complex UdLMB disease, who underwent OCT-guided angioplasty using DKC technique. Angiographic follow-up was performed in all patients at 1 year to identify patients with SBR. Patients with SBR group were compared with patients without SBR (NSBR group) for OCT parameters during index procedure.

RESULTS

Twelve (20%) patients developed SBR at 1-year follow-up. The SBR group had longer SB lesion (18.8 ± 3.2 vs. 15.3 ± 3.7 mm, p = 0.004) and neo-metallic carinal length (2.1 vs. 0.1 mm, p < 0.001) when compared to the NSBR group. Longer neo-metallic carinal length was associated with the absence of the dumbbell sign, presence of hanging stent struts across the SB ostium on OCT of final MB pullback. On multivariate regression analysis, SB distal reference diameter (DRD) and SB stent expansion were identified as independent predictors of SBR with SB-DRD of ≤2.8 mm (area under curve-0.73, sensitivity-83.3%, and specificity-62.5%) and SB stent expansion of ≤89% (area under curve-0.88, sensitivity-83.3%, and specificity- 81.2%) as the best cut off values to predict SBR.

CONCLUSIONS

SB DRD and SB stent expansion are the OCT predictors of future SBR after UdLMB angioplasty using DKC technique.

Contemporary Left Main Percutaneous Coronary Intervention: A State-of-the-art Review

The majority of the left ventricular myocardium is supplied by the left main coronary artery. Atherosclerotic obstruction of the left main coronary artery therefore leads to significant myocardial jeopardy. Coronary artery bypass surgery (CABG) has been the gold standard for left main coronary artery disease in the past. However, advancements in technology have established percutaneous coronary intervention (PCI) as a standard, safe and reasonable alternative to CABG, with comparable outcomes. Contemporary PCI of left main coronary artery disease comprises careful patient selection, accurate technique guided by either intravascular ultrasound or optical coherence tomography and - if necessary - physiological assessment using fractional flow reserve. This review focuses on current evidence from registries and randomised trials comparing PCI with CABG, procedural tips and tricks, adjuvant technologies and the triumph of PCI.

Intravascular imaging for left main stem assessment: An update on the most recent clinical data

Left main (LM) stem has different structural and anatomical characteristics compared to all of the other segments of the coronary tree, thus its management through percutaneous coronary intervention (PCI) is a challenge and is associated with worse clinical outcome and higher need for revascularization as compared to other lesion settings. Intravascular imaging, by means of intravascular ultrasound (IVUS) or optical coherence tomography (OCT), is an important tool for LM PCI guidance, aiming at improving the immediate performance and the long term outcome of this procedure. Following current guidelines and recent scientific findings, IVUS becomes important to firstly assess, and finally evaluate the result of LM stenting, according to the experience and preferences of the operator. The role of OCT still remains to be defined, but recent data is shedding light also on this imaging technique. The aim of this review is to highlight the latest scientific advancements regarding intravascular imaging in LM coronary artery disease.

Optical Coherence Tomography: An Eye Into the Coronary Artery

Optical coherence tomography (OCT) is slowly but surely gaining a foothold in the hands of interventional cardiologists. Intraluminal and transmural contents of the coronary arteries are no longer elusive to the cardiologist's probing eye. Although the graduation of an interventionalist in imaging techniques right from naked eye angiographies to ultrasound-based coronary sonographies to the modern light-based OCT has been slow, with the increasing regularity of complex coronary cases in practice, such a transition is inevitable. Although intravascular ultrasound (IVUS) due to its robust clinical data has been the preferred imaging modality in recent years, OCT provides a distinct upgrade over it in many imaging and procedural aspects. Better image resolution, accurate estimation of the calcified lesion, and better evaluation of acute and chronic stent failure are the distinct advantages of OCT over IVUS. Despite the obvious imaging advantages of OCT, its clinical impact remains subdued. However, upcoming newer trials and data have been encouraging for expanding the use of OCT to wider indications in clinical utility. During percutaneous coronary intervention (PCI), OCT provides the detailed information (dissection, tissue prolapse, thrombi, and incomplete stent apposition) required for optimal stent deployment, which is the key to successfully reducing the major adverse cardiovascular event (MACE) and stent-related morbidities. The increasing use of OCT in complex bifurcation stenting involving the left main (LM) is being studied. Also, the traditional pitfalls of OCT, such as additional contrast load for image acquisition and stenting involving the ostial and proximal LM, have also been overcome recently. In this review, we discuss the interpretation of OCT images and its clinical impact on the outcome of procedures along with current barriers to its use and newer paradigms in which OCT is starting to become a promising tool for the interventionalist and what can be expected for the immediate future in the imaging world.

Diagnostic Performance of Frequency-Domain Optical Coherence Tomography to Predict Functionally Significant Left Main Coronary Artery Stenosis

Aims

The aim of this study was to assess the safety and diagnostic efficacy of frequency-domain optical coherence tomography (FD-OCT) in identifying functional severity of the left main coronary artery (LM) stenosis determined by fractional flow reserve (FFR).

Methods and Results

101 patients with LM lesion (20-70% diameter stenosis angiographically) underwent FFR measurement and FD-OCT imaging of the LM. The following parameters were measured by FD-OCT in the LM: reference lumen area (RLA), reference lumen diameter (RLD), minimum lumen area (MLA), minimum lumen diameter (MLD), % lumen area stenosis, and % diameter stenosis. The LM lesions were analyzable by FD-OCT in 88/101 (87.1%) patients. FFR at maximum hyperemia was ≤0.80 in 39/88 (44.3%) patients. FFR values were correlated significantly with FD-OCT-derived LM lumen parameters. An MLA cutoff value of 5.38 mm² had the highest sensitivity and specificity of 82% and 81%, respectively, followed by an MLD of 2.43 mm (sensitivity 77%, specificity 72%) and AS of 60% (sensitivity 72%, specificity 72%) for predicting FFR <0.80.

Conclusions

FD-OCT is a safe and feasible imaging technique for the assessment of LM stenosis. An FD-OCT-derived MLA of ≤5.38 mm² strongly predicts the functional severity of an LM lesion.

Optical coherence tomography, intravascular ultrasound or angiography guidance for distal left main coronary stenting. The ROCK cohort II study

OBJECTIVES

to test the safety and efficacy of intravascular imaging and specifically optical coherence tomography (OCT) as a diagnostic tool for left main angioplasty and analyze the mid-term outcome accordingly.

BACKGROUND

Clinical data and international guidelines recommend the use of intravascular imaging ultrasound (IVUS) to guide left main (LM) angioplasty. Despite early experience using OCT in this setting is encouraging, the evidence supporting its use is still limited.

METHODS

ROCK II is a multicenter, investigator-driven, retrospective European study to compare the performance of IVUS and OCT versus angiography in patients undergoing distal-LM stenting. The primary study endpoint was target-lesion failure (TLF) including cardiac death, target-vessel myocardial infarction and target-lesion revascularization. We designed this study hypothesizing the superiority of intravascular imaging over angiographic guidance alone, and the non-inferiority of OCT versus IVUS.

RESULTS

A total of 730 patients, 377 with intravascular-imaging guidance (162 OCT, 215 IVUS) and 353 with angiographic guidance, were analyzed. The one-year rate of TLF was 21.2% with angiography and 12.7% with intravascular-imaging (p = 0.039), with no difference between OCT and IVUS (p = 0.26). Intravascular-imaging was predictor of freedom from TLF (HR 0.46; 95% CI 0.23-0.93: p = 0.03). Propensity-score matching identified three groups of 100 patients each with no significant differences in baseline characteristics. The one-year rate of TLF was 16% in the angiographic, 7% in the OCT and 6% in the IVUS group, respectively (p = 0.03 for IVUS or OCT vs. angiography). No between-group significant differences in the rate of individual components of TLF were found.

CONCLUSIONS

Intravascular imaging was superior to angiography for distal LM stenting, with no difference between OCT and IVUS.

Optical coherence tomography to guide percutaneous coronary intervention of the left main coronary artery: the LEMON study

BACKGROUND

Intravascular ultrasound (IVUS)-guided PCI improves the prognosis of left main stem (LMS) PCI and is currently recommended by international guidelines. Although OCT resolution is greater than that of IVUS, this tool is not yet recommended in LMS angioplasty due to the absence of data.

AIMS

This pilot study aimed to analyse the feasibility, safety and impact of OCT-guided LMS PCI.

METHODS

This prospective, multicentre trial investigated whether patients might benefit from OCT-guided PCI for mid/distal LMS according to a pre-specified protocol. The primary endpoint was procedural success defined as follows: residual angiographic stenosis <50% + TIMI 3 flow in all branches + adequate OCT stent expansion (LEMON criteria).

RESULTS

Seventy patients were included in the final analysis (median age: 72 [64-81] years, 73% male). The OCT pre-specified protocol was applied in all patients. The primary endpoint was achieved in 86% of subjects. Adequate stent expansion was observed in 86%, significant edge dissection in 30% and residual significant strut malapposition in 24% of the cases. OCT guidance modified the operators' strategy in 26% of the patients. The rate of one-year survival free from major adverse clinical events was 98.6% (97.2-100).

CONCLUSIONS

This pilot study is the first to report the feasibility and performance of OCT-guided LMS PCI according to a pre-specified protocol.

Longitudinal stent elongation or shortening after deployment in the coronary arteries: which is dominant?

Background

Stent manufacturers always record stent shortening data while they do not record stent elongation data. The aim of this study is to identify both stent shortening and elongation occurring after deployment in the coronary arteries and know their percentage.

Results

The length of coronary stents was measured by intravascular ultrasound (IVUS) by (1) edge-to-edge (E-E) length, measured from the appearance of the first distal strut to the last proximal strut, and (2) area-to-area (A-A) length, measured from the first distal struts seen at more than one IVUS quadrant to the last proximal struts seen at more than one IVUS quadrant. Stent shortening was defined as both E-E and A-A lengths were shorter than the manufacturer box-stated length (shortened group). Stent elongation was defined as both E-E and A-A lengths were longer than the manufacturer box-stated length (elongated group), otherwise unchanged group. Consecutive 102 stents deployed in ischemic patients were included. Stent elongation was detected in 67.6% (69 stents), and shortening was detected in 15.7% (16 stents), while unchanged stents were detected in 16.7% (17 stents). Although the 3 groups had similar box-stated length and predicted foreshortened length, they had significantly different measurements by IVUS, p<0.001 for each comparison. Differences from box-stated length were 1.9±1.4mm, −1.4±0.4mm, and 0.4±0.3mm, respectively, p<0.001. The elongated group had significantly longer differences from the corresponding box-stated and predicted foreshortened lengths, while the shortened group had significantly shorter differences from the corresponding box-stated length and similar foreshortened length. By multinomial regression analysis, the plaque-media area and stent deployment pressure were the independent predictors of the stent length groups, p=0.015 and p=0.026, respectively.

Conclusions

Change in stent length is not only shortening—as mentioned in the manufacturer documents—but also stent elongation. Stent elongation is dominant, and the most important predictors of longitudinal stent changes are plaque-media area and stent deployment pressure.

The absence of evidence is not the evidence of absence: A case report on the challenges in diagnosing ostial left main stenosis

Because left main (LM) coronary artery stenosis is known to have higher mortality and morbidity compared to lesions in other territories, an early diagnosis and management are crucial to prevent worse outcomes. Due to limitations of coronary angiography (CA), the diagnosis of ostial LM stenosis solely based on CA may result in underdiagnosis of such lesions. Therefore, additional testing is often needed either by pressure wire or intravascular ultrasound (IVUS) to make appropriate diagnosis. We, hereby, present a case of left main ostial stenosis in a 56-year-old male that was missed on multiple coronary angiograms, and highlights many of the considerations in the diagnosis of LM disease.

The role of intravascular ultrasound in percutaneous coronary intervention of complex coronary lesions

Intravascular ultrasound (IVUS) is a catheter-based coronary imaging technique. It utilises the emission & subsequent detection of reflected high frequency (30-60 MHz) sound waves to create high resolution, cross-sectional images of the coronary artery. IVUS has been the cornerstone of intracoronary imaging for more than two decades. When compared to the invasive coronary angiogram which studies only the silhouette of the contrast-filled artery lumen, IVUS also crucially images the vessel wall. Because of this capability, IVUS has greatly facilitated understanding of the coronary atherosclerosis process. Such insights from IVUS reveal how commonly and extensively plain angiography underestimates the true extent of coronary plaque, the characteristics of plaques prone to rupture and cause acute coronary syndromes (lipid rich, thin cap atheroma), and a realisation of the widespread occurrence of vessel remodelling in response to atherosclerosis. Similarly, IVUS has historically provided salutary mechanistic insights that have guided many of the incremental advances in the techniques of percutaneous coronary intervention (PCI). Examples include mechanisms of in-stent restenosis, and the importance of high-pressure post-dilatation of stents to ensure adequate stent apposition and thereby reduce the occurrence of stent thrombosis. IVUS also greatly facilitates the choice of correct diameter and length of stent to implant. Overall, a compelling body of evidence indicates that use of intravascular ultrasound in PCI helps to achieve optimal technical results and to mitigate the risk of adverse cardiac events. In this review, the role of intravascular ultrasound as an adjunct to PCI in complex coronary lesions is explored. The complex coronary situations discussed are the left main stem, ostial stenoses, bifurcation stenoses, thrombotic lesions, the chronically occluded coronary artery, and calcified coronary artery disease. By thorough review of the available evidence, we establish that the advantages of IVUS guidance are particularly evident in each of these complex CAD subsets. In particular, some consider the use of IVUS to be almost mandatory in left main PCI. A comparison with other intracoronary imaging techniques is also explored.

Evaluation of Left Main Coronary Artery Using Optical Frequency Domain Imaging and Its Pitfalls

Objectives

We aimed to assess the quality of optical frequency domain imaging (OFDI) of the left main (LM) arterial wall and describe and analyse potential artefacts in this setting.

Background

OFDI is increasingly used to assess ambiguous lesions and optimize LM percutaneous coronary intervention. However, its ability to provide artefact-free high-quality images of coronary ostia and large segments such as the LM remains uncertain.

Methods

We included 42 consecutive patients who underwent OFDI, including LM imaging. Each OFDI frame was subdivided into four quadrants and analysed. The number of quadrants with artifacts was calculated within the proximal, mid, and distal LM and the first 5 mm of the left anterior descending artery (LAD) and/or left circumflex artery (LCX).

Results

The quadrants analysis showed an overall artifact rate of 8.9%, mostly out-of-field (45.1%) or residual blood (44.7%) artefacts. Most artifacts were located in the proximal LM (18.6%) with a stepwise reduction of artifact rates towards distal segments (mid LM 5.8%; distal LM 3.6%, ostial LAD 2.6%, and ostial LCX 0%; p < 0.001). While 20 (48.8%) patients had angiographically visible plaques, OFDI showed plaques in 32 patients (76.2%; p=0.007).

Conclusion

OFDI can accurately evaluate the LM and detect and assess angiographically unvisualized atherosclerotic plaques providing accurate assessment of >90% of the quadrants of the LM and the ostia of its bifurcation branches. However, artifacts mainly located in the proximal LM and decreasing distally in a stepwise fashion should be considered in the interpretation of OFDI in this setting.

Use of Optical Coherence Tomography in Coronary Artery Disease: Review Article

Optical coherence tomography is a catheter-based imaging modality in heart catheterizations, which provides a significantly higher resolution of intravascular pathology by means of using light as opposed to ultrasound. The applications of this modality may include a detailed assessment of atherosclerotic plaques, stent evaluation including coverage and restenosis and percutaneous coronary intervention optimization. In this article, we provide a review of current literature highlighting the advantages and disadvantages of the use of optical coherence tomography in the catheterization lab.

[Left main PCI: Current treatment]

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

Intracoronary Optical Coherence Tomography 2018: Current Status and Future Directions

The advent of intravascular imaging has been a significant advancement in visualization of coronary arteries, particularly with optical coherence tomography (OCT) that allows for high-resolution imaging of intraluminal and transmural coronary structures. Accumulating data support a clinical role for OCT in a multitude of clinical scenarios, including assessing the natural history of atherosclerosis and modulating effects of therapies, mechanisms of acute coronary syndromes, mechanistic insights into the effects of novel interventional devices, and optimization of percutaneous coronary intervention. In this state-of-the-art review, we provide an overview of the published data on the clinical utility of OCT, highlighting the areas that need further investigation and the current barriers for further adoption of OCT in interventional cardiology practice.

Routine use of optical coherence tomography in bioresorbable vascular scaffold implantation: insights on technique optimization and long-term outcomes

BACKGROUND

Data from prior studies have shown increased risk of adverse outcomes with bioresorbable vascular scaffolds (BVS) compared with drug-eluting stents.

OBJECTIVE

The objective of this study was to study the long-term outcomes with routine use of optical coherence tomography (OCT) for optimization of BVS implantation.

PATIENTS AND METHODS

Clinical, procedural, and outcome data were collected for all patients who received ABSORB BVS between February 2014 and March 2016 in our tertiary center (n=86). Preimplantation and postimplantation OCT was performed in all cases. Outcomes of interest included acute device success and long-term clinical outcomes including cardiac mortality, target vessel myocardial infarction, ischemia-driven target lesion revascularization, and scaffold thrombosis.

RESULTS

A total of 86 patients were included (106 lesions, 115 BVS implanted). Mean age was 59.5±10.9 years, with 66% men. Mean lesion length was 25.2±15.6 mm and mean reference vessel diameter was 3.42±0.45 mm. Type B2/C accounted for 40% of the lesions. All scaffold implantations followed the predilation, proper sizing, and postdilation strategy. Of the 115 scaffolds analyzed, 11 (9.5%) required further intervention based on prespecified OCT endpoints. On multivariate regression analysis, complex coronary lesion (type B2/C) was the single independent predictor of OCT use in scaffold optimization (odds ratio=6.3, 95% confidence interval: 1.3-7.8, P=0.02). At a mean follow-up duration of 31±7.1 months, no cases of cardiac mortality, target vessel myocardial infarction, ischemia-driven target lesion revascularization, or scaffold thrombosis were reported.

CONCLUSION

Operators may consider OCT use for optimization of BVS implantation particularly in patients with complex coronary lesions.

Treatment strategies for coronary bifurcation lesions made easy in the current era by introduction of the BIFURCAID app

Coronary bifurcation lesions account for 15-20% of all percutaneous coronary interventions. Percutaneous revascularization of these lesions is technically challenging and results in lower success rates than nonbifurcation lesions. There are unique procedural considerations and techniques that are employed in the percutaneous revascularization of these lesions. Our objective is to define the procedural complexities of treating coronary bifurcation lesions and describe the leading provisional and dedicated two stent techniques used to optimize procedural and clinical results, as described in the BIFURCAID app.

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.

Appropriate use criteria for optical coherence tomography guidance in percutaneous coronary interventions : Recommendations of the working group of interventional cardiology of the Netherlands Society of Cardiology

Introduction

Optical coherence tomography (OCT) enables detailed imaging of the coronary wall, lumen and intracoronary implanted devices. Responding to the lack of specific appropriate use criteria (AUC) for this technique, we conducted a literature review and a procedure for appropriate use criteria.

Methods

Twenty-one of all 184 members of the Dutch Working Group on Interventional Cardiology agreed to evaluate 49 pre-specified cases. During a meeting, factual indications were established whereupon members individually rated indications on a 9-point scale, with the opportunity to substantiate their scoring.

Results

Twenty-six indications were rated ‘Appropriate’, eighteen indications ‘May be appropriate’, and five ‘Rarely appropriate’. Use of OCT was unanimously considered ‘Appropriate’ in stent thrombosis, and ‘Appropriate’ for guidance in PCI, especially in distal left main coronary artery and proximal left anterior descending coronary artery, unexplained angiographic abnormalities, and use of bioresorbable vascular scaffold (BVS). OCT was considered ‘Rarely Appropriate’ on top of fractional flow reserve (FFR) for treatment indication, assessment of strut coverage, bypass anastomoses or assessment of proximal left main coronary artery.

Conclusions

The use of OCT in stent thrombosis is unanimously considered ‘Appropriate’ by these experts. Varying degrees of consensus exists on the appropriate use of OCT in other settings.

Electronic supplementary material

The online version of this article (10.1007/s12471-018-1143-z) contains supplementary material, which is available to authorized users.

Long term outcomes of drug-eluting stent versus coronary artery bypass grafting for left main coronary artery disease: a meta-analysis

Background

It is still controversial whether percutaneous coronary intervention with drug-eluting stent (DES) is safe and effective compared to coronary artery bypass graft surgery (CABG) for unprotected left main coronary artery (ULMCA) disease at long-term follow up (≥ 3 years).

Methods

Eligible studies were selected by searching PubMed, EMBASE, and Cochrane Library up to December 6, 2016. The primary endpoint was a composite of death, myocardial infarction (MI) or stroke during the longest follow-up. Death, cardiac death, MI, stroke and repeat revascularization were the secondary outcomes.

Results

Four randomized controlled trials and twelve adjusted observational studies involving 14,130 patients were included. DES was comparable to CABG regarding the occurrence of the primary endpoint (HR = 0.94, 95% CI: 0.86–1.03). Besides, DES was significantly associated with higher incidence of MI (HR = 1.56, 95% CI: 1.09–2.22) and repeat revascularization (HR = 3.09, 95% CI: 2.33–4.10) compared with CABG, while no difference was found between the two strategies regard as the rate of death, cardiac death and stroke. Furthermore, DES can reduce the risk of the composite endpoint of death, MI or stroke (HR = 0.80, 95% CI: 0.67–0.95) for ULMCA lesions with SYNTAX score ≤ 32.

Conclusions

Although with higher risk of repeat revascularization, PCI with DES appears to be as safe as CABG for ULMCA disease at long-term follow up. In addition, treatment with DES could be an alternative interventional strategy to CABG for ULMCA lesions with low to intermediate anatomic complexity.

Intravascular imaging in coronary artery disease

Although it is the method used by most interventional cardiologists to assess the severity of coronary artery disease and guide treatment, coronary angiography has many known limitations, particularly the fact that it is a lumenogram depicting foreshortened, shadowgraph, planar projections of the contrast-filled lumen rather than imaging the diseased vessel itself. Intravascular imaging-intravascular ultrasound and more recently optical coherence tomography-provide a tomographical or cross-sectional image of the coronary arteries. These techniques are clinically useful to answer questions such as whether the stenosis is clinically relevant; the identification of the culprit lesion; or whether the plaque (or patient) is at high risk of future adverse events. They can also be used to optimise stent implantation to minimise stent-related adverse events, provide answers to the likelihood of distal embolisation or peri-procedural myocardial infarction during stent implantation, and provide reasons for stent thrombosis or restenosis. This review considers the usefulness of intravascular imaging in day-to-day practice.

Difference in vascular response between sirolimus-eluting- and everolimus-eluting stents in ostial left circumflex artery after unprotected left main as observed by optical coherence tomography

BACKGROUND

Kissing-balloon technique (KBT) is commonly performed during percutaneous coronary intervention of distal unprotected left main coronary artery (ULM) aiming at obtaining optimal opening of the side branch (left circumflex artery; LCX) ostium. Nonetheless, detailed evaluation of vascular response to stents in LCX ostium is lacking. We therefore evaluated the vascular response to different drug-eluting stents (DES) in ostial LCX after ULM by means of optical coherence tomography (OCT).

METHODS

We prospectively enrolled 38 consecutive patients with ULM disease, who were treated with single-stent procedure using DES, crossover the ULM-left anterior descending artery (LAD) followed by KBT. Twelve patients were treated with sirolimus-eluting stents (SES) and 26 patients were treated with everolimus-eluting stents (EES). OCT was conducted at post-PCI and 9-month follow-up. We evaluated the DES-vessel interactions and number of stent struts at the side branch (LCX) ostium (SO) at post-PCI, and compared the narrowing of ostial area at LCX between SES and EES.

RESULTS

Post-procedure, the number of stent struts at SO was significantly higher in SES compared to EES (median 14.47% vs 0.19%, p<0.001). The narrowing of LCX ostial area at follow-up was more pronounced in SES compared with EES (29.16% vs 2.46%, respectively, p<0.001). Linear regression analysis showed a high correlation between the number of stent struts in LCX ostium and ostial area narrowing (r=0.771, p<0.001).

CONCLUSIONS

OCT showed differences between EES- and SES-vessel interactions at ULM bifurcation PCI. Number of LCX ostium struts at post-PCI impacted the narrowing of ostial area at 9-month follow-up.

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.

Left Main Percutaneous Coronary Intervention

Significant unprotected left main stem (ULMS) disease is in approximately 5% to 7% of patients undergoing coronary angiography. Historically, coronary artery bypass grafting has been the gold standard treatment of these patients. With recent advances in stent technology, adjunctive pharmacotherapy, and operator experience, percutaneous coronary intervention (PCI) is increasingly regarded as a viable alternative treatment option, especially in patients with favorable coronary anatomy (low and intermediate SYNTAX (Synergy Between Percutaneous Coronary Intervention with TAXUS and Cardiac Surgery) scores). This article aims to discuss the evidence supporting PCI for ULMS disease, current guidelines, and technical aspects.

Practical based approach to left main bifurcation stenting

Despite the recent developments that have been made in the field of percutaneous left main (LM) intervention, the treatment of distal LM bifurcation remains challenging. The provisional one-stent approach for LM bifurcation has shown more favorable outcomes than the two-stent technique, making the former the preferred strategy in most types of LM bifurcation stenosis. However, elective two-stent techniques, none of which has been proven superior to the others, are still used in patients with severely diseased large side branches to avoid acute hemodynamic compromise. Selecting the proper bifurcation treatment strategy using meticulous intravascular ultrasound evaluation for side branch ostium is crucial for reducing the risk of side branch occlusion and for improving patient outcomes. In addition, unnecessary complex intervention can be avoided by measuring fractional flow reserve in angiographically isolated side branches. Most importantly, good long-term clinical outcomes are more related to the successful procedure itself than to the type of stenting technique, emphasizing the greater importance of optimizing the chosen technique than the choice of method.

Optical Coherence Tomography For the Detection of the Vulnerable Plaque

Morphological characteristics of the atheromatous plaque have been associated with the development of plaque rupture and the pathogenesis of acute coronary syndromes (ACS). Plaques with a specific morphological phenotype that are at high risk of causing ACS are called vulnerable plaques, and can be identified in vivo through the use of intracoronary imaging. Optical coherence tomography (OCT) is a high-resolution intravascular imaging modality that enables detailed visualization of atheromatous plaques. Consequently, OCT is a valuable research tool for examining the role of morphological characteristics of atheromatous plaques in the progression of coronary artery disease and plaque destabilisation, which leads to the clinical manifestation of ACS. This article summarises the pathophysiological insights obtained by OCT imaging in the formation and rupture of the vulnerable plaque.

Incidence and Clinical Significance of Poststent Optical Coherence Tomography Findings

Background—

Optical coherence tomography (OCT) was recently introduced to optimize percutaneous coronary intervention. However, the exact incidence and significance of poststent OCT findings are unknown.

Methods and Results—

A total of 900 lesions treated with 1001 stents in 786 patients who had postprocedure OCT imaging were analyzed to evaluate the incidence of poststent OCT findings and to identify the OCT predictors for device-oriented clinical end points, including cardiac death, target vessel–related myocardial infarction, target lesion revascularization, and stent thrombosis. Patients were followed up to 1 year. Stent edge dissection was detected in 28.7% of lesions, and incomplete stent apposition was detected in 39.1% of lesions. The incidences of smooth protrusion, disrupted fibrous tissue protrusion, and irregular protrusion were 92.9%, 61.0%, and 53.8%, respectively. Small minimal stent area, defined as a lesion with minimal stent area <5.0 mm 2 in a drug-eluting stent or <5.6 mm 2 in a bare metal stent, was observed in 40.4% of lesions. One-year device-oriented clinical end points occurred in 33 patients (4.5%). Following adjustment, irregular protrusion and small minimal stent area were independent OCT predictors of 1-year device-oriented clinical end points ( P =0.003 and P =0.012, respectively).

Conclusions—

Abnormal poststent OCT findings were frequent. Irregular protrusion and small minimal stent area were independent predictors of 1-year device-oriented clinical end points, which were primarily driven by target lesion revascularization.

Percutaneous Coronary Intervention Planning and Optimization with Optical Coherence Tomography

Coronary angiography confirms or excludes coronary artery disease, assesses lesions severity, and helps to decide percutaneous coronary interventions (PCI). Coronary angiography has clear limitations. Intravascular imaging guides PCI. Frequency domain optical coherence tomography (OCT) gained attention for accurate planning and guidance of complex PCI. High-speed OCT image acquisition enables prompt vessel assessment in stable and unstable patients. The high-resolution images provide precise tissue characterization and a reliable quantitative assessment of the coronary pathology. Immediately after stent implantation, OCT allows accurate evaluation of stent expansion and symmetry. Real-time angio-OCT co-registration integrates OCT into the PCI workflow for accurate decision making.

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.

Invasive assessment modalities of unprotected left main stenosis

Among all coronary lesions, the decision-making process for the treatment of unprotected left main (ULM) stem lesions is still challenging. Indeed, the optimal therapeutic strategy for patients with ULM disease remains controversial: coronary artery bypass grafting was established as the gold standard, but it is without doubt that percutaneous coronary intervention (PCI) performed by experienced operators achieves good results at long term follow up, especially in cases where the ostium and/or shaft of ULM are treated. Thanks to the widespread use of invasive assessment of atherothrombotic ULM stenosis, improved selection of PCI cases and techniques of stenting, better outcomes are now possible. This review seeks to define the place of PCI in ULM disease by describing the different modalities of ULM stenosis assessment.

Mechanisms, pathophysiology, and clinical aspects of incomplete stent apposition

Incomplete stent apposition (ISA) is characterized by the lack of contact of at least 1 stent strut with the vessel wall in a segment not overlying a side branch; it is more commonly found in drug-eluting stents than bare-metal stents. The accurate diagnosis of ISA, initially only possible with intravascular ultrasound, can currently be performed with higher accuracy by optical coherence tomography, which also enables strut-level assessment due to its higher axial resolution. Different circumstances related both to the index procedure and to vascular healing might influence ISA occurrence. Although several histopathology and clinical studies linked ISA to stent thrombosis, potential selection bias precluded definitive conclusions. Initial studies usually performed single time point assessments comparing overall ISA percentage and magnitude in different groups (i.e., stent type), thus hampering a comprehensive understanding of its relationship with vascular healing. Serial intravascular imaging studies that evaluated vascular response heterogeneity recently helped fill this gap. Some particular clinical scenarios such as acute coronary syndromes, bifurcations, tapered vessels, overlapping stents, and chronic total occlusions might predispose to ISA. Interventional cardiologists should be committed to optimal stent choices and techniques of implantation and use intravascular imaging guidance when appropriate to aim at minimizing acute ISA. In addition, the active search for new stent platforms that could accommodate vessel remodeling over time (i.e., self-expandable stents) and for new polymers and/or eluting drugs that could induce less inflammation (hence, less positive remodeling) could ultimately reduce the occurrence of ISA and its potentially harmful consequences.