Optical coherence tomography for guidance of distal cell recrossing in bifurcation stenting: choosing the right cell matters

Optical coherence tomography to guide percutaneous coronary intervention

Percutaneous coronary intervention (PCI) has been most commonly guided by coronary angiography. However, to overcome the inherent limitations of conventional coronary angiography, there has been an increasing interest in the adjunctive tools of intracoronary imaging for PCI guidance. Recently, optical coherence tomography (OCT) has garnered substantial attention as a valid intravascular imaging modality for guiding PCI. However, despite the unparalleled high-resolution imaging capability of OCT, which offers detailed anatomical information on coronary lesion morphology and PCI optimisation, its broad application in routine PCI practice remains limited. Several factors may have curtailed the widespread adoption of OCT-guided PCI in daily practice, including the transitional challenge from intravascular ultrasound (IVUS), the experienced skill required for image acquisition and interpretation, the lack of a uniform algorithm for OCT-guided PCI optimisation, and the limited clinical evidence. Herein, we provide an in-depth review of OCT-guided PCI, involving the technical aspects, optimal strategies for OCT-guided PCI, and the wide application of OCT-guided PCI in various anatomical subsets. Special attention is given to the latest clinical evidence from recent randomised clinical trials with respect to OCT-guided 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.).

How to use three-dimensional optical coherence tomography effectively in coronary bifurcation stenting

Imaging-guided coronary bifurcation intervention has improved clinical outcomes due to the appropriate size selection of the devices and optimization of the procedure (sufficient stent expansion, reduction of stent malapposition, appropriate stent landing zone, and detection of vessel dissection). In particular, three-dimensional optical coherence tomography (3D OCT) facilitates clear visualization of stent configuration and guidewire position, which promotes optimal guidewire crossing to the side branch. Successive side branch dilation leads to wide ostial dilation with less strut malapposition. However, the link connection of the stent located on the bifurcated carina has been found to be an impediment to sufficient opening of the side branch, resulting in incomplete strut apposition. In such cases, the aggressive proximal optimization technique improves the jailing strut pattern, and 3D OCT navigates the guidewire crossing to the optimal cell that is most likely to be expanded sufficiently, which is not always a distal cell. In two-stent deployment, 3D OCT facilitates optimal guidewire crossing, which leads to less metallic carina, clustering, and overlapping. The present review describes a method of clear visualization and assessment with 3D OCT and discusses the efficacy of 3D OCT in coronary bifurcation stenting in clinical practice.

Impact of late lumen loss on clinical outcomes of side branch bifurcation lesions treated by drug-coated balloon angioplasty with main branch stenting

BACKGROUND

Drug-coated balloon (DCB) angioplasty for side branches with main branch stenting is effective for bifurcation lesions and reduces late lumen loss (LLL) in side branches. However, the predictors and clinical implications of LLL after DCB angioplasty are largely unexplored.

METHODS

Among 181 patients undergoing DCB angioplasty for side branches with drug-eluting stent implantation for main branches between 2016 and 2018, we enrolled 138 patients (138 lesions) undergoing follow-up coronary angiography within 1 year. The 1-year cumulative rates of target lesion revascularization (TLR) and major adverse cardiac events (MACE: defined as a composite of all-cause death, myocardial infarction, and TLR) were compared between patients with late lumen gain (LLG) (LLG group) and those with LLL (LLL group).

RESULTS

The binary restenosis rate of the side branch was 8.0% (11 lesions), mean LLL was -0.14 ± 0.43 mm, and LLG was observed in 99 lesions (71.7%). The DCB size/reference vessel diameter ratio showed mild discrimination (area under the curve, 0.60; 95% confidence interval, 1.2-65.0; p = 0.03) for predicting the side branch progression. The 1-year cumulative rates of MACE and TLR were not significantly different but numerically lower in the LLG group than in the LLL group (2.0% vs. 7.8%, p = 0.11 and 2.0% vs. 7.7%, p = 0.11, respectively). Lumen regression after DCB angioplasty for side branches are associated with improved clinical outcomes.

CONCLUSIONS

The DCB size relative to the reference vessel diameter is a predictor of late lumen enlargement in side branches.

Online three-dimensional OFDI-guided versus angiography-guided PCI in bifurcation lesions: design and rationale of the randomised OPTIMUM trial

AIMS

The feasibility of offline optical coherence tomography (OCT) guidance in bifurcation (with either two-dimensional or three-dimensional images) and its potential benefits have been demonstrated in retrospective studies; however, these have not yet been investigated prospectively. The aim of this trial is to determine the superiority of online three-dimensional optical frequency domain imaging (3D-OFDI)-guided stenting to angiography-guided percutaneous coronary intervention (PCI) in terms of incomplete stent apposition (ISA) at the bifurcation segment.

METHODS AND RESULTS

The OPTIMUM trial is a randomised, superiority, multicentre clinical trial. The primary endpoint of this trial is the post-procedural percentage of malapposed struts assessed by OFDI in the main branch bifurcation region after final kissing balloon dilatation (FKBD). A total of 106 patients will be randomly allocated to either 3D-OFDI guidance or angiography guidance PCI. Bifurcation lesions will be treated with a provisional single-stent strategy using the Ultimaster sirolimus-eluting stent. Patients randomised to the 3D-OFDI guidance arm will undergo OFDI assessment in the main branch (MV) after rewiring into the jailed side branch following stent implantation, while in the angiography guidance arm re-crossing of a wire into the side branch will be performed using conventional fluoroscopic/angiographic guidance. In patients in the 3D-OFDI guidance arm, if the position of the wire is not located in the optimal cell, further attempts to redirect the wire to the optimal cell will be performed, with subsequent OFDI acquisitions to confirm the re-crossing position. The proximal optimisation technique and FKBD are mandatory in this trial. The study will provide a 90% power to show superiority of 3D-OFDI guidance PCI compared with angiography-guided PCI.

CONCLUSIONS

The OPTIMUM trial will be the first prospective, randomised trial to evaluate the efficacy and safety of online 3D-OFDI-guided PCI in bifurcation lesions. ClinicalTrials.gov Identifier: NCT02972489.

A Randomized Trial Evaluating Online 3-Dimensional Optical Frequency Domain Imaging-Guided Percutaneous Coronary Intervention in Bifurcation Lesions

Supplemental Digital Content is available in the text.

Background:

Clinical implications of online 3-dimensional optical frequency domain imaging (3D-OFDI)-guided stenting for bifurcation lesions have not been investigated in the randomized controlled trials. The purpose of this study was to determine whether online 3D-OFDI-guided stenting is superior to angiography-guided percutaneous coronary intervention (PCI) in terms of incomplete stent apposition at the bifurcation segment.

Methods:

The OPTIMUM trial (Online 3-Dimensional Optical Frequency Domain Imaging to Optimize Bifurcation Stenting Using UltiMaster Stent) was a randomized, multicenter clinical trial. Eligible patients had an angiographically significant stenosis in the bifurcation lesion treated with a provisional single stent strategy using the Ultimaster sirolimus eluting stent. Patients were randomly allocated to either online 3D-OFDI-guided or angiography-guided PCI. Patients randomized to 3D-OFDI guidance underwent online 3D-OFDI assessment after rewiring into the jailed side branch after stenting and proximal optimization technique, while in the angiography guidance arm, rewiring was performed using conventional fluoroscopic/angiographic guidance. The primary end point of this trial was the postprocedural average percentage of malapposed struts per lesion assessed by OFDI in the confluence zone of the main and side branches.

Results:

Between June 8, 2017 and September 26, 2018, 110 patients with 111 bifurcation lesions were randomized at 4 Japanese centers. Of these, 56 patients with 57 lesions were treated with 3D-OFDI-guided PCI, whereas 54 patients with 54 lesions were treated with angiography-guided PCI. In the 3D-OFDI guidance arm, the feasibility of online 3D-OFDI was 98.2%. The average percentage of incomplete stent apposition per lesion at bifurcation was lower in the 3D-OFDI guidance arm than that in the angiography guidance arm (19.5±15.8% versus 27.5±14.2%, P=0.008). The superiority of the 3D-OFDI guidance arm was also confirmed in the strut level analysis (odds ratio: 0.54 [95% CI, 0.36–0.81]; P=0.003).

Conclusions:

Online 3D-OFDI-guided bifurcation PCI was superior to angiography-guided bifurcation PCI in terms of acute incomplete stent apposition at bifurcation.

Registration:

URL: https://www.clinicaltrials.gov. Unique identifier: NCT02972489.

How can optical coherence tomography be used to optimize percutaneous coronary intervention?

Optical coherence tomography (OCT) imaging provides high resolution assessment of coronary parietal and endoluminal abnormalities. Clinical evidence and intuitive utilization make this tool relevant for use in daily practice in the catheterization laboratory. In the present review, we summarize the benefits of OCT for the optimization of percutaneous coronary intervention (PCI) in daily practice. First, we focus on the characterization of lesion type with a view to anticipating challenges during PCI. Then, we describe the utility of OCT to identify culprit lesions and ambiguous angiographic findings. Finally, we outline targets for optimization after PCI and the mechanisms underlying stent failure.

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.

Critical aspects of balloon position during final proximal optimization technique (POT) in coronary bifurcation stenting

OBJECTIVES

In a coronary bifurcation bench model, to determine the effects of side branch (SB) wire crossing position and balloon position on the stent scaffolding after the final proximal optimization technique (POT).

BACKGROUND

POT performed as a final step after SB dilatation or kissing balloon inflation (KBI) has been widely advocated despite limited evidence.

METHODS

Thirty-one stent implantations in bifurcation phantoms were performed using a one-stent provisional technique with (KBI) (n = 13), with POT-side-POT technique (n = 12) or with the two-stent culotte technique (n = 6). SB wiring was performed through either a proximal or a distal stent cell and confirmed by optical coherence tomography. Final POT was performed with the balloon positioned either across or proximal to the SB takeoff. The area of the opened stent cell in front of the SB was assessed by 3D reconstructed microcomputation tomography scans performed before and after Final POT.

RESULTS

In cases with metallic carina, final POT across the SB takeoff caused SB rejailing. Regardless of stent technique and wire position, a Final POT across the SB takeoff reduced the SB cell opening area by 43% [32%;58%] (n = 15). The largest reduction (54-70%) was found after the POT-side-POT technique in procedures with a proximal wiring. Final POT performed proximal to the SB takeoff caused limited or no SB cell opening area reduction (4% [0.6%;6%] [n = 16]).

CONCLUSION

Final POT with balloon positioned across the SB takeoff in a narrow angle bifurcation reduces largest stent cell area in front of the SB ostium and may cause SB rejailing in cases with metallic carina.

Summary of Practice Considerations for Percutaneous Coronary Intervention of Left Main Bifurcation Disease

Left main bifurcation percutaneous coronary intervention is a challenging subset that requires expertise in techniques that are in constant modification. Imaging is important in lesion preparation and optimising outcomes. The interventionalist needs to be highly skilled in the different techniques, as missteps may lead to stent thrombosis and critical in-stent restenosis. Lesion classification between simple and complex identifies those who would best benefit from a two-stent technique. Current technical approaches and practice considerations are summarised in this manuscript.

Comparison of diagnostic performance in assessing the rewiring position into a jailed side branch between online 3D reconstruction systems version 1.1 and 1.2 derived from optical frequency domain imaging

The three-dimensional reconstruction of optical coherence tomography and optical frequency domain imaging (3D-OCT/OFDI) helps optimize bifurcation percutaneous coronary interventions (PCIs) with side branch (SB) dilatation by identifying the optimal rewiring position. 3D-OCT/OFDI’s diagnostic performance for assessing the rewiring position into a jailed SB is unknown. We retrospectively evaluated the diagnostic performances of a conventional (ver. 1.1) and a new (ver. 1.2) online 3D-OFDI reconstruction system based on an offline 3D reconstruction system’s performance. We analyzed 45 patients’ 52 OFDI pullbacks with main vessel stenting followed by rewiring into a jailed SB for coronary bifurcation lesions. We counted the undetected stent struts in the polygon of confluence as the stent detection performance. We assessed the diagnostic agreement regarding the rewiring position into a jailed SB by the three 3D reconstruction systems. The percentage of undetected struts and the diagnostic agreement of ver.1.2 were significantly better than those of ver.1.1 [5.1 ± 5.1% vs. 30.2 ± 14.2%; p < 0.0001, and 94.2% (49/52) vs. 76.9% (40/52); p = 0.0120]. The new online 3D-OFDI reconstruction system provides better diagnostic performance than the conventional online system for assessing the rewiring position into a jailed SB.

[Hot issues in bifurcation lesions PCI in 2019]

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 still debated but involves careful assessment, planning and a sequential provisional approach. The preferential strategy 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. Final kissing balloon inflation is not recommended in all cases. In the minority of lesions where two stents are required, careful deployment and optimal expansion are essential to achieve a long-term result. Intracoronary imaging techniques (IVUS, OCT) and FFR are useful endovascular tools to achieve optimal results.

Efficacy of the proximal optimization technique on crossover stenting in coronary bifurcation lesions in the 3D-OCT bifurcation registry

AIM

We sought to investigate the efficacy of the proximal optimization technique (POT) on crossover stenting followed by side branch (SB) dilation under optical coherence tomography guidance in a multicenter registry study.

METHODS AND RESULTS

A total of 135 bifurcation lesions in 134 patients were divided into POT (n = 52) and non-POT groups (n = 83). The POT was performed before SB dilatation (pre-POT; n = 26), finally (final-POT; n = 12), at both timing (re-POT; n = 13), and uncertain (n = 1). There were no significant intergroup differences in the success rate of guide wire re-crossing (GWR) into the optimal cell (72% vs. 65%), incidence of the link-free type in the configuration of the SB jailed struts (51% vs. 49%), or incomplete strut apposition at the bifurcation (13 ± 11% vs. 10 ± 9%). However, insufficient stent expansion close to the carina in the proximal main vessel (MV) due to inappropriate POT was likely to induce greater incomplete strut apposition (ISA) around the bifurcation. Only re-POT provided more symmetric proximal MV expansion, while pre- and final-POT did not.

CONCLUSION

The POT did not provide the expected beneficial effects, such as reduction of ISA or more optimal GWR, under the OCT guidance. Wide stent expansion in the proximal MV induced by the POT increased the likelihood of achieving optimal GWR, whereas symmetric stent expansion was provided by re-POT.

Imaging during percutaneous coronary intervention for optimizing outcomes

Angiography is the current gold standard for imaging during percutaneous coronary interventions but has significant limitations. Catheter-based intravascular imaging techniques such as intravascular ultrasound and the more recent optical coherence tomography have the potential to overcome these limitations and thus optimize clinical outcomes. In this update, we discussed the current applications of the available imaging techniques, existing evidence, continuing unmet needs, and potential areas for further research.

OCT-guided Percutaneous Coronary Intervention in Bifurcation Lesions

Coronary artery bifurcation lesions remain challenging despite significant advancements in stent technology and development of specific bifurcation stenting approaches. Optical coherence tomography (OCT) is the intracoronary imaging technique with the highest resolution and can generate automatically contoured lumen areas across the variable geometry of bifurcation lesions. Knowledge of plaque severity and composition facilitates planning of the best strategy for percutaneous coronary intervention (PCI) and stenting. In particular, the provisional stent strategy preferred in this context can be modified when there is high risk of side-branch compromise at the ostium after main vessel stenting. OCT is unique because it allows the identification of the site of guide wire crossing, an important determinant of the final result. OCT can also be used to assess the procedural success of new dedicated bifurcation stent technologies and for the evaluation at follow-up of potential predictors of stent thrombosis, including stent malapposition, stent under-expansion and stent-edge dissection. Finally, the development of 3D OCT allows a better evaluation of coronary anatomy — particularly of side branch ostium that is difficult to visualise by 2D OCT — further improving the value of this technique in guiding PCI in these patients.

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.

A review in enormity of OCT and its enduring understanding of vulnerable plaque in coronary bifurcation lesion

Optical coherence tomography (OCT) has emerged as one of the most promising tools to assist the optimization of percutaneous coronary intervention (PCI). Its ability to provide unique information on the plaque at high risk for rupture, plaque composition, the thickness of the fibrous cap, the presence of macrophage and thrombi has not only assisted simple PCI but also in many complex bifurcation lesions PCI. OCT has helped to provide valuable anatomic information to optimize stent implantation and adapt PCI strategy in individual patients. This review article summarizes the current role of OCT as an imaging technology and prediction of vulnerable plaque, its site and composition at the coronary bifurcation lesions for supporting the clinical decision.

Impact of guidewire recrossing point into stent jailed side branch for optimal kissing balloon dilatation: core lab 3D optical coherence tomography analysis

AIMS

We aimed to investigate the influence of the guidewire recrossing point on the incidence of incomplete stent apposition (ISA) after kissing balloon dilatation (KBD), and also clinical and angiographic outcome at nine months in a prospective multicentre registry.

METHODS AND RESULTS

One hundred and five patients underwent single crossover stenting across the side branch (SB) and subsequent KBD. The jailing configuration of the SB orifice and the guidewire recrossing position were assessed by off-line 3D-OCT in the core lab. We defined the cases that achieved both link-free carina configuration and distal recrossing as the LFD group (54 cases), and the other cases as the non-LFD group (51 cases). ISA in the LFD group was significantly smaller than that in the non-LFD group (6.7±5.9% vs. 17.0±10.5%, p<0.0001). The distal recrossing rate was 83%. Proximal recrossing increased ISA compared with distal recrossing, particularly in parallel bifurcations (17.1±10.1% vs. 6.3±6.0%, p<0.0001). At follow-up, though event rates did not differ, SB restenosis in the non-LFD group tended to be higher than in the LFD group (20.5% vs. 8.3%, p=0.1254).

CONCLUSIONS

The guidewire recrossing point and the location of a stent link at the SB orifice had an influence on the ISA. KBD with optimal conditions under 3D-OCT guidance may reduce SB restenosis.

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.

Feasibility and usefulness of three-dimensional optical coherence tomography guidance for optimal side branch treatment in coronary bifurcation stenting

BACKGROUND

For the treatment of coronary bifurcation lesions, optimal guidewire (GW) recrossing after main vessel stenting is important for good stent apposition at the side branch (SB) orifice in kissing balloon inflation (KBI).

METHODS

We analyzed 150 bifurcation lesions treated with single stenting following KBI in the three-dimensional optical coherence tomography (3D-OCT) bifurcation registry study (2015-16) and a single center experience (2012-16). OCT examination was performed after GW recrossing to the SB and after KBI. Patients were divided into two-dimensional (2D, n=78) and 3D groups (n=72) according to 2D- or 3D-OCT guidance. GW recrossing position, jailing configuration of the stent over the SB (divided into Link-connecting type: stent link connecting to the carina and Link-free type: no stent link at the carina) and stent apposition were compared between the groups.

RESULTS

Distal GW recrossing was achieved in 75.6% and 91.7% in the 2D and 3D groups, respectively (P=0.004). Compared with the 2D group, the incidence of incomplete stent apposition (ISA) toward the SB in the 3D group tended to be lower in the whole cohort (14.5±13.6% vs 10.0±9.0%, P=0.077), and was significantly lower in left main trunk bifurcations (18.7±12.8% vs 10.3±8.9%, P=0.014). Independent contributors to ISA were the Link-connecting type (β 0.089, P<0.001), distal GW recrossing (β -0.078, P=0.001), and age (β -0.0020, P=0.012).

CONCLUSION

Optimal GW recrossing under 3D-OCT guidance is feasible and improves stent apposition, which may lead to a better clinical outcome in the treatment of bifurcation lesions.

Current clinical applications of coronary optical coherence tomography

Optical coherence tomography (OCT) is an intra-coronary diagnostic technique that provides detailed imagings of blood vessels in the current cardiac catheterization laboratory. The higher resolution of OCT often provides superior delineation of each structure compared with intravascular ultrasound (IVUS), and it can reliably visualize the microstructure of normal and diseased arteries. The capabilities of OCT are well suited for the identification of calcified plaque and neointima formation after stent implantation. It has been reported that OCT-guided percutaneous coronary intervention (PCI) resulted in equivalent clinical and angiographic outcomes in comparison with IVUS-guided PCI. Recently, the three-dimensional reconstruction of OCT and a real-time point-to-point correspondence between coronary angiographic and OCT/OFDI images have been developed and provide useful information to PCI operators. The unique capabilities of OCT as an investigational tool for high-risk lesions will serve the cardiology community well, as it moves us toward a better understanding of atherosclerotic plaque. In addition, because of the development of new OCT technology, OCT has become a notable catheter-based imaging technology that can provide practical guidance for PCI in clinical settings.

Re-crossing the distal cell in bifurcation verified by using an enhanced stent visualization system and optical coherence tomography: a report of two cases

The coronary guidewire re-crossing position before the final kissing balloon post-dilation is important to reduce the incidence of incomplete stent apposition in bifurcation lesions. Angiography and intravascular ultrasonography are unreliable at detecting the site of wire re-crossing. The high resolution of optical coherence tomography (OCT) offers the advantage of precise assessment of construction in bifurcation. However, the OCT technique still has some limitations, including the requirement for additional contrast and expense. We present two cases where the ClearStent Live system technique was used to estimate the wire location, which was verified by using OCT. In conclusion, ClearStent can be used with or to replace the intracoronary imaging technique in selected cases.

Optical coherence tomography assessment of a complex bifurcation lesion treated with double kissing Crush technique: A case report

The DEFINITION (Impact of the complexity of bifurcation lesions treated with drug-eluting stents) study has provided a novel classification to evaluate the complexity of coronary bifurcation lesion according to coronary angiography, but angiographic imaging due to its low resolution and inherited limitation may result in an inaccurate adjudication.We used optical coherence tomography (OCT) to further evaluate the coronary characteristics in a patient with "simple" bifurcation lesion which was classified by the DEFINITION criteria. However, a "complex" bifurcation lesion was defined and confirmed according to the OCT results.A double kissing Crush stenting approach was adopted to treat this "complex" case finally. The immediate and long-term angiographic and OCT results were excellent.OCT may be useful imaging modality to classify complexity of coronary bifurcation lesion and subsequently guide its treatment strategy.

Percutaneous Coronary Intervention for Bifurcation: How Can We Outperform the Provisional Strategy?

In the era of drug-eluting stents, the provisional stenting strategy has been established as the default strategy in percutaneous coronary intervention for bifurcation lesions. However, emerging evidence shows that, in selected situations, the complex strategy of stenting both vessels regardless could reduce side-branch restenosis without penalty. In particular, the double kissing crush technique has been proven to outperform the provisional strategy and other complex strategies in randomized trials. In this review, we present the evidence comparing the 2 strategies and individual stenting techniques and discuss the roles of other optimization techniques such as final kissing balloon inflation, proximal optimization technique, intravascular ultrasonography, and optical coherence tomography. Finally, we suggest a practical approach for choosing the optimal strategy for intervention with coronary bifurcation lesions.

Comparative Analysis of Sequential Proximal Optimizing Technique Versus Kissing Balloon Inflation Technique in Provisional Bifurcation Stenting: Fractal Coronary Bifurcation Bench Test

OBJECTIVES

This study used a fractal bifurcation bench model to compare 6 optimization sequences for coronary bifurcation provisional stenting, including 1 novel sequence without kissing balloon inflation (KBI), comprising initial proximal optimizing technique (POT) + side-branch inflation (SBI) + final POT, called "re-POT."

BACKGROUND

In provisional bifurcation stenting, KBI fails to improve the rate of major adverse cardiac events. Proximal geometric deformation increases the rate of in-stent restenosis and target lesion revascularization.

METHODS

A bifurcation bench model was used to compare KBI alone, KBI after POT, KBI with asymmetric inflation pressure after POT, and 2 sequences without KBI: initial POT plus SBI, and initial POT plus SBI with final POT (called "re-POT"). For each protocol, 5 stents were tested using 2 different drug-eluting stent designs: that is, a total of 60 tests.

RESULTS

Compared with the classic KBI-only sequence and those associating POT with modified KBI, the re-POT sequence gave significantly (p < 0.05) better geometric results: it reduced SB ostium stent-strut obstruction from 23.2 ± 6.0% to 5.6 ± 8.3%, provided perfect proximal stent apposition with almost perfect circularity (ellipticity index reduced from 1.23 ± 0.02 to 1.04 ± 0.01), reduced proximal area overstretch from 24.2 ± 7.6% to 8.0 ± 0.4%, and reduced global strut malapposition from 40 ± 6.2% to 2.6 ± 1.4%.

CONCLUSIONS

In comparison with 5 other techniques, the re-POT sequence significantly optimized the final result of provisional coronary bifurcation stenting, maintaining circular geometry while significantly reducing SB ostium strut obstruction and global strut malapposition. These experimental findings confirm that provisional stenting may be optimized more effectively without KBI using re-POT.

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.

Bioresorbable scaffolds for treatment of coronary bifurcation lesions: Critical appraisal and future perspectives

Bioresorbable vascular scaffolds have been recently introduced as a novel paradigm for coronary artery disease treatment allowing temporary vessel support and drug delivery without indefinite coronary caging, potentially reducing the long-term limitation of metallic stents. The scientific community has rapidly embraced this concept and bioresorbable devices have been introduced in clinical practice. However, despite the fact that bifurcation lesions represent a large and challenging subset in the field of interventional cardiology, this subgroup of lesions have been avoided in the initial experience with bioresorbable scaffolds and clear recommendations on methodological approaches are lacking. In the present report, we describe the various techniques for bifurcation treatment with bioresorbable scaffolds and the theoretical advantages and disadvantages of this technology in different scenarios, with a glimpse to challenging subsets and possible complications. Therefore, we aim to provide experience based insights and practical guidance for bioresorbable scaffold implantation in bifurcation lesions. © 2016 Wiley Periodicals, Inc.

Correction of Stent Distortion and Overhanging Stent Struts during Left Main Bifurcation Stenting by Selective Distal Stent Cell Re-Wiring: A Novel Guidewire Approach

Stent malapposition and overhanging stent struts in front of the side branch (SB) ostium are not uncommon following bifurcation stenting that might lead to stent thrombosis. We herein present 2 cases, in which optical frequency domain imaging and intravascular ultrasound effectively revealed stent malapposition and overhanging struts inside the ostium of the SB following left main coronary artery stenting. Therefore, we introduced a novel technique for rectification of these incidental findings by selective SB re-wiring through the most distal stent cell with the adjunctive help of a double lumen microcatheter.

KEY WORDS

Distal stent strut; Left main bifurcation; Overhanging struts; Side branch re-crossing; Stent optimization.

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.

Stenting of coronary bifurcation lesions: a literature and technical review

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

3D optical coherence tomography: new insights into the process of optimal rewiring of side branches during bifurcational stenting

AIMS

We describe three-dimensional optical coherence tomography (3D-OCT) guided bifurcation stenting and the clinical utility of 3D-OCT.

METHODS AND RESULTS

Twenty-two consecutive patients who underwent OCT examination to confirm the recrossing position after stent implantation in a bifurcation lesion were enrolled. Frequency domain OCT images were obtained to check the recrossing position and 3D reconstructions were performed off-line. The recrossing position was clearly visualised in 18/22 (81.8%) cases. In 13 cases, serial 3D-OCT could be assessed both before and after final kissing balloon post-dilation (FKBD). We divided these cases into two groups according to the presence of the link between hoops at the carina: free carina type (n=7) and connecting to carina type (n=6). All free carina types complied with the distal rewiring. The percentage of incomplete stent apposition (%ISA) of free carina type at the bifurcation segment after FKBD was significantly smaller than that of the connecting to carina type (0.7±0.9% vs. 12.2±6.5%, p=0.0074).

CONCLUSIONS

3D-OCT confirmation of the recrossing into the jailed side branch is feasible during PCI and may help to achieve distal rewiring and favourable stent positioning against the side branch ostium, leading to reduction in ISA and potentially better clinical outcomes.