Duration of Dual Antiplatelet Therapy after Percutaneous Coronary Intervention of Unprotected Left Main Coronary Artery Stenosis: 6 versus 12 Months

Background/Objectives: For patients with percutaneous coronary intervention (PCI) of an unprotected left main coronary artery (uLMCA) stenosis, the optimal duration of dual antiplatelet therapy (DAPT) remains a matter of debate. The purpose of this study was to compare clinical outcomes of 6- versus 12-month DAPT duration in patients with PCI of an uLMCA and stable angina. Methods: In this retrospective analysis, we included consecutive patients of our centre who underwent PCI of uLMCA stenosis for stable angina and who received DAPT with acetylsalicylic acid and clopidogrel for either 6 or 12 months. The primary endpoint was the composite of all-cause mortality, myocardial infarction, and target lesion revascularization at one year. Secondary endpoints included individual components of the primary endpoint, definite/probable stent thrombosis, and bleeding. Clinical outcomes were assessed by unadjusted analysis and by inverse probability of treatment weighting (IPTW). Results: Out of 984 included patients, 339 (34.5%) received DAPT for 6 months and 645 (65.5%) for 12 months. The primary endpoint occurred in 51 patients (15.2%) in the 6-month group and in 104 (16.3%) in the 12-month group (p = 0.674). Incidences of stent thrombosis (0.9% versus 0.3%, p = 0.224) and BARC 3,4,5 bleeding (6% versus 5.8%, p = 0.808) were also comparable in both groups. We found no significant differences in the primary endpoint and its components or BARC 3,4,5 bleeding between 6 and 12 months. Conclusions: Our findings do not support the extension of DAPT beyond 6 months after PCI for uLMCA in patients with stable angina.

Optical Coherence Tomography to Assess Proximal Side Optimization Technique in Crush Stenting

Aim

The aim of this study was to explore the potential intraprocedural benefits of the Proximal Side Optimization (PSO) technique by Optical Coherence Tomography (OCT).

Methods

A case series of 10 consecutive true bifurcation lesions, with severe long pathology of long side branch (SB), were randomly assigned to be treated by standard DK Crush procedure (non-PSO group) as compared to DK Crush in PSO modification (PSO group). The data from OCT investigation before crushing of the SB Drug-Eluting Stent (DES), after crushing, after first kissing balloon inflation (KBI), and after final angiography were compared between the two groups (Public trials registry ISRCTN23355755).

Results

All 10 cases were successfully treated by the assigned technique. The two groups were similar in terms of indications for the procedure, bifurcation angle, and stent dimensions. As compared to the non-PSO, the PSO group showed larger proximal SB stent areas (5.8 ± 1.8 vs. 4.5 ± 0.5 mm²; p = 0.02), the larger delta between distal and proximal stent areas before crush (1.5 ± 0.7 vs. 0.6 ± 0.5 mm²; p = 0.004), and the larger Space of Optimal Wiring (SOW) after Crush (5.3 ± 1.8 vs. 2.5 ± 1.1 mm²; p = 0.02). The gaps in scaffolding within the ostial segment of the Side Branch DES were found in two patients from the non-PSO group.

Conclusion

The DK Crush in PSO modification results in larger SB DES and SOW areas with better apposition to the vessel wall. As result, the SB DES acquires a funnel shape, which reduces the risk of passage outside the SB stent struts during re-wiring, thus, allowing predictable and secure results.

Clinical outcomes of the proximal optimisation technique (POT) in bifurcation stenting

BACKGROUND

Optimal deployment of coronary stents in a bifurcation lesion remains a matter of debate.

AIMS

We sought to capture the daily practice of bifurcation stenting by means of a worldwide registry and to investigate how post-implantation deployment techniques influence clinical outcomes.

METHODS

Data from the e-ULTIMASTER registry were used to perform an analysis of 4,395 patients undergoing percutaneous coronary intervention for bifurcation lesions. Inverse probability of treatment weights (IPTW) propensity score methodology was used to adjust for any baseline differences. The primary outcome of interest was target lesion failure (TLF) at one year (follow-up rate 96.2%).

RESULTS

The global one-year TLF rate was low (5.1%). The proximal optimisation technique (POT) was used in 33.9% of cases and was associated with a reduction in the adjusted TLF rate (4.0% [95% confidence interval: 3.0-5.1%] vs 6.0% [5.1-6.9%], p<0.01) due to a reduction of all components of this composite endpoint, except for cardiac death. Stent thrombosis was also positively impacted (0.4% [0.04-0.7%] vs 1.3% [0.8-1.7%], p<0.01). POT benefit was uniform across subgroups. Conversely, the use of the kissing balloon technique (36.5%) did not influence the adjusted TLF rate.

CONCLUSIONS

Despite a low one-year failure rate in this large bifurcation stenting cohort, POT was associated with a further reduction in the event rate and a uniform benefit across subgroups, suggesting systematic use of this deployment technique regardless of the bifurcation anatomy and stenting technique.

The importance of proximal optimization technique with intravascular imaging guided for stenting unprotected left main distal bifurcation lesions: The Milan and New-Tokyo registry

OBJECTIVES

This study evaluated the 5-years outcomes of intracoronary imaging-guided proximal optimization technique (POT) for percutaneous coronary intervention (PCI) in patients with unprotected left main distal bifurcation lesions (ULMD).

BACKGROUND

The long-term effects of POT with intracoronary imaging guide in PCI for ULMD have been unclear.

METHODS

Between January 2005 and December 2015, we identified 1832 consecutive patients who underwent DES implantation for ULM distal bifurcation lesions. Of them, 780 (56.1%) patients underwent POT with intravascular imaging guidance (optimal expansion group). Residual 611 (43.9%) patients did not undergo either POT or intravascular imaging or both (suboptimal expansion group). Analysis using propensity score adjustment was performed. The primary endpoint was target lesion failure (TLF) defined as a composite of cardiac death, target lesion revascularization (TLR), and myocardial infarction.

RESULTS

TLF rate at 5 years was significantly lower in optimal expansion group than that in suboptimal expansion group [adjusted HR 0.65, 95% CI (0.48-0.87), p = 0.004]. Cardiac mortality was significantly lower in optimal expansion group than that in suboptimal expansion group [adjusted HR 0.46, 95% CI (0.27-0.79), p = 0.004]. The multivariable analysis identified POT with intravascular imaging guide [adjusted HR 0.65, 95% CI (0.48-0.87), p = 0.004] as an independent predictor of TLF.

CONCLUSIONS

Intravascular imaging guided POT was strongly associated with the reduced risk of TLF at 5 years after PCI for ULMD, mainly driven by reducing cardiac mortality.

Influence of balloon location during proximal optimization technique (POT): A finite element analysis

Proximal Optimization Technique (POT)is a post-expansion technique that must be completed after single-stent implantation for the coronary bifurcation. The optimal location for the distal balloon shoulder during POT remains debatable. In the present study, the finite element method is applied to simulate POT after single-stent implantation in the coronary bifurcation. Three different balloon locations based on the distal shoulder relative to the carina cut plane were analyzed: 1) "proximal":1mm before carina cut plane; 2) "standard": at the carina cut plane; and 3) "distal": 1 mm after the carina cut plane. The computational results showed differences in stent, vessel morphology, and vessel wall stress due to the different balloon locations. However, when distal balloon shoulder was located between two adjacent stent rings, it formed the distal cell of the stent, the best stent apposition, least stent structs obstruction at SB ostial. Moreover, best opening effect of distal cell of the stent can be achieved, with the least damage to the vessel wall.

Proximal Side-Branch Optimization in Crush Stenting: A Step-by-Step Technical Approach in a Silicone Phantom Model

Provisional single drug-eluting stent (DES) strategy remains the standard of care in simple bifurcation lesions which comprise the vast majority of coronary bifurcations. Nevertheless, the presence of complex bifurcations which are defined based on the 1) Side Branch (SB) lesion length of >10 mm and 2) SB ostial diameter stenosis of >70% are approached with a 2-DES strategy upfront. The bifurcation angle will further define the most appropriate technique, with T-stenting more suitable in angulations close to 90°, Culotte and the family of Crush techniques more appropriate for acute angles of <75°. The Crush techniques which are composed of the classic Crush, mini-Crush and double kissing Crush (DK-Crush) share the core principle of protruding the SB DES within the Main Branch (MB) to minimize the risk of ostial SB restenosis, which remains the most prevalent etiology of stent failure during 2-stent approach in bifurcations. Proximal Side Optimization (PSO) is an additional technical consideration to further optimize the protruding SB struts enabling 1) optimal SB strut accommodation to the larger MB vessel diameter, 2) strut enlargement that will further facilitate effortless rewiring for kissing balloon inflation (KBI) avoiding unfavorable guide wire advancement in the peri-ostial SB area.

Impact of Kissing Balloon in Patients Treated With Ultrathin Stents for Left Main Lesions and Bifurcations

Background:

There are limited data regarding the impact of final kissing balloon (FKI) in patients treated with percutaneous coronary intervention using ultrathin stents in left main or bifurcations.

Methods:

All patients undergoing left main or bifurcations percutaneous coronary intervention enrolled in the RAIN registry (Very Thin Stents for Patients With MAIN or BiF in Real Life: The RAIN, a Multicenter Study) evaluating ultrathin stents were included. Major adverse cardiac event (a composite of all-cause death, myocardial infarction, target lesion revascularization, and stent thrombosis) was the primary end point, while its components, along with target vessel revascularization, were the secondary end points. The main analysis was performed comparing patients with and without FKI after adjustment with inverse probability of treatment weighting. Subgroup analyses were performed according to FKI (short [<3 mm] versus long overlap), strategy (provisional versus 2-stent), routine versus bail-out FKI, and the use of imaging and proximal optimization technique.

Results:

Two thousand seven hundred forty-two patients were included. At 16 months (8–20) follow-up, inverse probability of treatment weighting adjusted rates of major adverse cardiac event were similar between FKI and no-FKI group (15.1% versus 15.5%; P =0.967), this result did not change with use of imaging, proximal optimization technique, or routine versus bail-out FKI. In the 2-stent subgroup, FKI was associated with lower rates of target vessel revascularization (7.8% versus 15.9%; P =0.030) and target lesion revascularization (7.3% versus 15.2%; P =0.032). Short overlap FKI was associated with a lower rate of target lesion revascularization compared with no FKI (2.6% versus 5.4%; P =0.034), while long overlap was not (6.8% versus 5.4%; P =0.567).

Conclusions:

In patients with bifurcations or unprotected left main treated with ultrathin stents, short overlap FKI is associated with less restenosis. In a 2-stent strategy, FKI was associated with less target vessel revascularization and restenosis.

Registration:

URL: https://www.clinicaltrials.gov ; Unique identifier: NCT03544294.

Histopathologic and physiologic effect of bifurcation stenting: current status and future prospects

Introduction: Coronary bifurcation lesions are involved in up to 20% of all percutaneous coronary interventions (PCI). However, bifurcation lesion intervention is associated with a high complication rate, and optimal treatment of coronary bifurcation is an ongoing debate.Areas covered: Both different stenting techniques and a variety of devices have been suggested for bifurcation treatment, including the use of conventional coronary stents, bioresorbable vascular scaffolds (BVS), drug-eluting balloons (DEB), and stents dedicated to bifurcations. This review will summarize different therapeutic approaches with their advantages and shortcomings, with special emphasis on histopathologic and physiologic effects of each treatment strategy.Expert opinion: Histopathology and clinical data have shown that a more simple treatment strategy is beneficial in bifurcation lesions, achieving superior results. Bifurcation interventions through balloon angioplasty or placement of stents can importantly alter the bifurcation's geometry and accordingly modify local flow conditions. Computational fluid dynamics (CFD) studies have shown that the outcome of bifurcation interventions is governed by local hemodynamic shear conditions. Minimizing detrimental flow conditions as much as possible should be the ultimate strategy to achieve long-term success of bifurcation interventions.

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.

[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.

Percutaneous coronary intervention for obstructive bifurcation lesions: the 14th consensus document from the European Bifurcation Club

The European Bifurcation Club recommends an approach to a bifurcation stenosis which involves careful assessment, planning and a sequential provisional approach. In the minority of lesions where two stents are required, careful deployment and optimal expansion are essential to achieve a long-term result.

The Proximal Optimization Technique Improves Clinical Outcomes When Treated without Kissing Ballooning in Patients with a Bifurcation Lesion

Background and Objectives

There are limited data regarding the clinical efficacy of the proximal optimization technique (POT) in the treatment of coronary bifurcation lesions. We investigated the influence of POT on the clinical outcomes of patients with coronary bifurcation lesions.

Methods

We enrolled a total of 1,191 patients with a bifurcation lesion with a side branch (SB) diameter ≥2.5 mm treated with a drug-eluting stent from 18 centers between January 2003 and December 2009. The primary outcome was major adverse cardiac events (MACEs: cardiac death, myocardial infarction or target lesion revascularization [TLR]). We performed one-to-many (1:N) propensity score matching with non-fixed matching ratio.

Results

POT was performed in 252 patients. During follow-up (median 37 months), the incidence of MACE was lower in the POT group than it was in the non-POT group (adjusted hazard ratio, 0.43; 95% confidence interval [CI], 0.24–0.79; p=0.006). After propensity score matching, these were 0.34; 95% CI, 0.17–0.69; p=0.003 for MACE and 0.37; 95% CI, 0.17–0.78; p=0.01 for TLR. The use of POT was associated with significantly lower TLR in patients treated without kissing ballooning, but was not in those who underwent kissing ballooning (p for interaction=0.03).

Conclusions

In coronary bifurcation lesions with a large SB, POT may be beneficial to improve long-term clinical outcome, particularly in patients treated without kissing ballooning during the procedure.

Trial Registration

ClinicalTrials.gov Identifier: NCT01642992

Technical Approaches to Left Main Coronary Intervention: Contemporary Best Practices

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

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.

Role of Proximal Optimization Technique Guided by Intravascular Ultrasound on Stent Expansion, Stent Symmetry Index, and Side-Branch Hemodynamics in Patients With Coronary Bifurcation Lesions

BACKGROUND

Bench models of coronary bifurcation lesions demonstrated that the proximal optimization technique (POT) expanded the stent and opened the side branch (SB). We investigated the role of POT guided by intravascular ultrasound on the main vessel (MV) stent expansion and SB fractional flow reserve (FFR) in patients with coronary bifurcation lesion.

METHODS AND RESULTS

In 40 patients with coronary bifurcation lesion, 120 intravascular ultrasound examinations of the MV were performed at baseline, after MV stenting, and POT followed by 95 FFR measurements of the SB. In the proximal stent segment, stent volume index and minimum stent area were larger after POT versus MV stenting (9.2±3.4 versus 7.40±2.0 mm³/mm and 7.65±1.8 versus 6.38±1.7 mm², respectively; P<0.01). In the bifurcation segment, minimum stent area was larger after POT versus MV stenting (6.45±2.1 versus 5.9±2.0 mm², respectively; P<0.05). POT expanded the stent symmetrically. After POT, SB FFR was <0.75 in 12 patients (30%), which improved to >0.75 after SB dilation or SB stenting+final POT. SB FFR was significantly higher after POT+SB dilation or SB stenting+final POT versus after MV stenting and POT.

CONCLUSIONS

This is the first study of POT guided by intravascular ultrasound in patients with coronary bifurcation lesion, demonstrating that POT symmetrically expanded the proximal and bifurcation segments of the stent. After POT, SB FFR was <0.75 in a third of patients, which improved to >0.75 after SB dilation or SB stenting+final POT.

Treatment of coronary bifurcation lesions: current knowledge and future perspectives

Coronary lesions at bifurcation sites are frequent and still remain a challenging subset for the interventional cardiologist. Although in the last years the provisional stenting technique has shown more consistent results, coronary bifurcation interventions still share a worse procedural success rate and increased rates of mid- and long-term cardiac events. Most of the dedicated devices proposed in the last few years have failed to show improved results when compared with standard devices. The broader use of imaging techniques, such as intravascular ultrasound and optical coherence tomography, lead to a better understanding of the real anatomy of bifurcations and has shown to be a great tool for percutaneous coronary intervention optimization. Preliminary results come from drug-coated balloons and bioresorbable vascular scaffolds, especially for the 'leave nothing behind' concept, particularly interesting in this setting of lesions.

Understanding the Coronary Bifurcation Stenting

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

Current Interventions for the Left Main Bifurcation

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

Double guide double wrist 5F left coronary artery transradial percutaneous coronary intervention and the X-Kiss technique

Percutaneous coronary intervention for bifurcated anatomy, particularly at the proximal left coronary artery site, requires guide catheters (GC) of at least 6 french and preferably larger in diameter. We describe a new trans-radial approach more suitable for small artery size: the simultaneous use of both radial arteries for double cannulation of the LMCA with 5F GC: each GC will target either the LM/LAD or the LM/CX artery (or LM-LAD/LM-LAD-1st diagonal branch) stenoses. The technique successfully was applied to 5 cases. When the technique was used for distal left main coronary artery stenoses (3 cases), a special crogss-like configuration obtained when guide catheters, coronary wires and balloons kissed was observed.

Contemporary Approach to Coronary Bifurcation Lesion Treatment

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

Hemodynamics of Stent Implantation Procedures in Coronary Bifurcations: An In Vitro Study

Stent implantation in coronary bifurcations presents unique challenges and currently there is no universally accepted stent deployment approach. Despite clinical and computational studies, the effect of each stent implantation method on the coronary artery hemodynamics is not well understood. In this study the hemodynamics of stented coronary bifurcations under pulsatile flow conditions were investigated experimentally. Three implantation methods, provisional side branch (PSB), culotte (CUL), and crush (CRU), were investigated using time-resolved particle image velocimetry to measure the velocity fields. Subsequently, hemodynamic parameters including wall shear stress, oscillatory shear index (OSI), and relative residence time (RRT) were calculated. The pressure field through the vessel was non-invasively quantified and pressure wave speeds were computed. The effects of each stented case were evaluated and compared against an un-stented case. CRU provided the lowest compliance mismatch, but demonstrated detrimental stent interactions. PSB, the clinically preferred method, and CUL maintained many normal flow conditions. However, PSB provided about a 300% increase in both OSI and RRT. CUL yielded a 10 and 85% increase in OSI and RRT, respectively. The results of this study support the concept that different bifurcation stenting techniques result in hemodynamic environments that deviate from that of un-stented bifurcations, to varying degrees.