Side branch predilatation during percutaneous coronary bifurcation intervention: Long-term mortality analysis

BACKGROUND

Side branch predilatation (SBPD) during coronary bifurcation interventions is a technique that is not recommended by the latest guidelines. However, the data about the clinical outcomes after SBPD are surprisingly few.

AIMS

The current study aimed to explore the association between SBPD and mortality in long-term follow-up.

METHODS

All patients with coronary bifurcation stenoses revascularized with percutaneous coronary intervention were included in a prospective registry. Patients with stable angina and a bifurcation lesion with ≥50% diameter stenosis were included in the current analysis. Patients were assigned to two groups - those with SBPD(+) and those without SBPD(-). Propensity score matching was performed to equalize the risk factors and severity of coronary artery disease between the groups. A Kaplan-Meier analysis with a log-rank test for between-group differences was also performed.

RESULTS

From January 2013 to June 2021, 813 patients were included in the final study population. The mean age was 67 (10) years. After propensity score matching, 648 patients remained for analysis - 324 in each group. At a median follow-up of 57 months patients in the SBPD(+) group had a higher all-cause mortality (n = 107 (33%) vs. n = 98 [30.2%]; P = 0.045) and cardiovascular mortality (n = 82 [25.3%] vs. n = 70 [21.6%]; P = 0.03) when compared with SBPD(-) patients. SBPD was independently associated with all-cause and cardiovascular mortality.

CONCLUSION

SBPD treatment of coronary bifurcation stenoses is associated with worse patient survival in the follow-up of up to 8 years. SBPD treatment gives better angiographic results, but this did not translate into better clinical outcomes.

Coronary microevaginations characterize culprit plaques and their inflammatory microenvironment in a subtype of acute coronary syndrome with intact fibrous cap: results from the prospective translational OPTICO-ACS study

AIMS

Coronary microevaginations (CMEs) represent an outward bulge of coronary plaques and have been introduced as a sign of adverse vascular remodelling following coronary device implantation. However, their role in atherosclerosis and plaque destabilization in the absence of coronary intervention is unknown. This study aimed to investigate CME as a novel feature of plaque vulnerability and to characterize its associated inflammatory cell-vessel-wall interactions.

METHODS AND RESULTS

A total of 557 patients from the translational OPTICO-ACS study programme underwent optical coherence tomography imaging of the culprit vessel and simultaneous immunophenotyping of the culprit lesion (CL). Two hundred and fifty-eight CLs had a ruptured fibrous cap (RFC) and one hundred had intact fibrous cap (IFC) acute coronary syndrome (ACS) as an underlying pathophysiology. CMEs were significantly more frequent in CL when compared with non-CL (25 vs. 4%, P < 0.001) and were more frequently observed in lesions with IFC-ACS when compared with RFC-ACS (55.0 vs. 12.7%, P < 0.001). CMEs were particularly prevalent in IFC-ACS-causing CLs independent of a coronary bifurcation (IFC-ICB) when compared with IFC-ACS with an association to a coronary bifurcation (IFC-ACB, 65.4 vs. 43.7%, P = 0.030). CME emerged as the strongest independent predictor of IFC-ICB (relative risk 3.36, 95% confidence interval 1.67-6.76, P = 0.001) by multivariable regression analysis. IFC-ICB demonstrated an enrichment of monocytes in both culprit blood analysis (culprit ratio: 1.1 ± 0.2 vs. 0.9 ± 0.2, P = 0.048) and aspirated culprit thrombi (326 ± 162 vs. 96 ± 87 cells/mm2, P = 0.017), while IFC-ACB confirmed the accumulation of CD4+ T cells, as recently described.

CONCLUSION

This study provides novel evidence for a pathophysiological involvement of CME in the development of IFC-ACS and provides first evidence for a distinct pathophysiological pathway for IFC-ICB, driven by CME-derived flow disturbances and inflammatory activation involving the innate immune system.

TRIAL REGISTRATION

Registration of the study at clinicalTrials.gov (NCT03129503).

Predictors of target lesion failure after treatment of left main, bifurcation, or chronic total occlusion lesions with ultrathin-strut drug-eluting coronary stents in the ULTRA registry

BACKGROUND

Data about the long-term performance of new-generation ultrathin-strut drug-eluting stents (DES) in challenging coronary lesions, such as left main (LM), bifurcation, and chronic total occlusion (CTO) lesions are scant.

METHODS

The international multicenter retrospective observational ULTRA study included consecutive patients treated from September 2016 to August 2021 with ultrathin-strut (<70 µm) DES in challenging de novo lesions. Primary endpoint was target lesion failure (TLF): composite of cardiac death, target-lesion revascularization (TLR), target-vessel myocardial infarction (TVMI), or definite stent thrombosis (ST). Secondary endpoints included all-cause death, acute myocardial infarction (AMI), target vessel revascularization, and TLF components. TLF predictors were assessed with Cox multivariable analysis.

RESULTS

Of 1801 patients (age: 66.6 ± 11.2 years; male: 1410 [78.3%]), 170 (9.4%) experienced TLF during follow-up of 3.1 ± 1.4 years. In patients with LM, CTO, and bifurcation lesions, TLF rates were 13.5%, 9.9%, and 8.9%, respectively. Overall, 160 (8.9%) patients died (74 [4.1%] from cardiac causes). AMI and TVMI rates were 6.0% and 3.2%, respectively. ST occurred in 11 (1.1%) patients while 77 (4.3%) underwent TLR. Multivariable analysis identified the following predictors of TLF: age, STEMI with cardiogenic shock, impaired left ventricular ejection fraction, diabetes, and renal dysfunction. Among the procedural variables, total stent length increased TLF risk (HR: 1.01, 95% CI: 1-1.02 per mm increase), while intracoronary imaging reduced the risk substantially (HR: 0.35, 95% CI: 0.12-0.82).

CONCLUSIONS

Ultrathin-strut DES showed high efficacy and satisfactory safety, even in patients with challenging coronary lesions. Yet, despite using contemporary gold-standard DES, the association persisted between established patient- and procedure-related features of risk and impaired 3-year clinical outcome.

Technical Complications of Coronary Bifurcation Percutaneous Interventions

Coronary bifurcation percutaneous interventions (PCI) comprise a challenging subset of patients with coronary artery disease. Beyond the well-known debate about single versus double stent strategies, which have different outcomes on mid- and long-term follow up, both strategies may be subject, although rarely, to several different technical complications, rarely reported in clinical trials, which need to be defined, classified, and understood by cardiovascular professionals involved in the management of patients with coronary bifurcation disease. The present paper aims to broaden the knowledge of the range of intraprocedural complications and relative treatment during PCI of coronary bifurcations.

Reliability and Safety of a Side-Branch Jailed Second-Generation Optical-Pressure Guidewire in a Physiology-Guided Bifurcation-PCI In Vitro Model

BACKGROUND

The treatment of a coronary bifurcation with a single stent (the provisional stenting technique) is associated with a good outcome in most cases. In the majority of cases, after provisional stenting technique, a residual significant angiographic stenosis is associated with the absence of ischemia when fractional flow reserve (FFR) is measured. Jailing an optical pressure guidewire in the side branch (SB) could potentially reduce unnecessary SB interventions after provisional stenting technique. The aim of this study was to compare distal pressure to aortic pressure ratio (Pd/Pa) measurements between 2 second-generation optical pressure guidewires in bifurcation treatment-a jailed wire (JW) and a second free-floating wire (FW) advanced into the SB after stenting.

METHODS

In an in vitro bifurcation hydrodynamic model with pressure sensors, a JW was advanced into the SB and the FW into the main branch. Bifurcation stenting is performed with the proximal optimization technique (POT)-side-POT technique using a 3.0 x 22-mm stent, a 4.0 x 12-mm noncompliant balloon for the POT, and a 2.5 x 12-mm semicompliant balloon for the SB opening. The same steps were performed in a second model where a surgical clamp was placed in the main vessel to lower overall absolute values pressures.

RESULTS

A strong correlation was found between JW and FW values (Pearson's coefficient, r=0.91). All wires could be safely retrieved.

CONCLUSION

In bifurcation stenting, the Pd/Pa value of a second-generation optical pressure guidewire jailed in the SB is reliable compared with a FW inserted after stent implantation.

Real-Life Outcomes of Coronary Bifurcation Stenting in Acute Myocardial Infarction (Zabrze-Opole Registry)

Percutaneous coronary intervention (PCI) of bifurcation lesions is a technical challenge associated with high risk of adverse events, especially in primary PCI. The aim of the study is to analyze long-term outcomes after PCI for coronary bifurcation in acute myocardial infarction (AMI). The outcome was defined as the rate of major adverse cardiac event related to target lesion failure (MACE-TLF) (death-TLF, nonfatal myocardial infarction-TLF and target lesion revascularization (TLR)) and the rate of stent thrombosis (ST). From 306 patients enrolled to the registry, 113 were diagnosed with AMI. In the long term, AMI was not a risk factor for MACE-TLF. The risk of MACE-TLF was dependent on the culprit lesion, especially in the right coronary artery (RCA) and side branch (SB) with a diameter >3 mm. When PCI was performed in the SB, the inflation pressure in SB remained the single risk factor of poor prognosis. The rate of cumulative ST driven by late ST in AMI was dependent on the inflation pressure in the main branch (MB). In conclusion, PCI of bifurcation culprit lesions should be performed carefully in case of RCA and large SB diameter and attention should be paid to high inflation pressure in the SB. On the contrary, the lower the inflation pressure in the MB, the higher the risk of ST.

6-year results of BiOSS stents in coronary bifurcation treatment

BACKGROUND

The wide variation in bifurcation anatomy has generated an ongoing search for stents explicitly designed for coronary bifurcations, and to date, results have been underachieved.

METHODS

The POLBOS I and POLBOS II were international, multicentre, randomized, open-label, controlled trials. Patients were randomly assigned to BiOSS Expert (in POLBOS I, biodegradable polymer eluting paclitaxel)/BiOSS LIM (in POLBOS II, biodegradable polymer eluting sirolimus) stent implantation or regular drug-eluting stent (rDES) deployment. A provisional T-stenting strategy was the default treatment option. The primary endpoint of this pooled data study was the cumulative rate of major adverse cardiovascular events (MACE) consisting of cardiac death, myocardial infarction (MI) and target lesion revascularization (TLR). Telephone follow-up was performed annually up to 72 months. (ClinicalTrials.gov Identifier: POLBOS I-NCT02192840, POLBOS II-NCT02198300).

RESULTS

The total study population consisted of 445 patients, 222 patients in the BiOSS group and 223 patients in the rDES group. The follow-up rate was 93.7% in the BiOSS group and 91.9% in the rDES group. At 72 months, there was no significant difference between BiOSS and rDES groups regarding MACE (25.7% vs 25.1%, HR 1.06, 95% CI 0.73-1.52), cardiac death (3.1% vs 4.0%, HR 0.94, 95% CI 0.43-2.34), MI (3.6% vs 4.9%, HR 0.76, 95% CI 0.32-2.89), TLR (18.9% vs 16.1%, HR 1.17, 95% CI 0.75-1.83) and stent thrombosis rates (0.9% vs 0.5%, HR 1.21, 95CI 0.75-2.09).

CONCLUSIONS

At the 6-year follow-up, clinically significant clinical events did not differ between BiOSS stents and rDES.

COmplex Bifurcation Lesions: RAndomized Comparison of Modified-T Stenting vs Reconstruction With Self-Expanding Stent and Bioresorbable Scaffold: COBRA II

OBJECTIVES

To evaluate the role of a double bioresorbable vascular scaffold (BVS) strategy in coronary bifurcations, alone or in combination with a dedicated bifurcation device.

METHODS

COBRA II is a prospective, single-center, randomized controlled trial. Patients were randomized to treatment with biolimus-eluting Axxess bifurcation device (Biosensors) in combination with Absorb BVS (Abbott Vascular) or a modified-T strategy using Absorb BVS. Optical coherence tomography (OCT) was performed post procedure and at 30 months. The primary endpoint was change in minimal luminal area (MLA) on OCT from baseline to 30-month follow-up. Clinical endpoints included major adverse cardiac event (MACE) rate.

RESULTS

From February 2016 to February 2017, a total of 15 patients with complex coronary bifurcation lesions were randomized to Axxess (n = 8) or modified-T strategy (n = 7). Procedure success rate was 100%. At 30-month follow-up, MLAs were significantly smaller than post procedure in proximal main vessel (MV), ostial distal MV, and ostial side branch (SB) after modified-T (mean difference, -3.1 ± 1.3 mm² [P<.001]; -2.1 ± 1.0 mm² [P<.01]; -2.1 ± 1.4 mm² [P=.03], respectively) and in ostial distal MV and ostial SB after Axxess (-2.1 ± 0.8 mm² [P<.001]; -1.6 ± 0.7 mm² [P<.01], respectively), while in proximal Axxess segment, the MLA remained stable (-0.1 ± 0.0; P=.93) and significantly larger than modified-T, mainly due to a smaller neointimal area (1.8 ± 0.7 mm² vs 3.2 ± 0.6 mm²; P<.001). Acute BVS strut discontinuities were observed in 53%, and late intraluminal dismantling was seen in 38% of patients. At 3 years, 1 MACE and no scaffold thromboses were observed.

CONCLUSIONS

In this serial imaging bifurcation study, BVS luminal dimensions were significantly smaller at 30 months, with acute strut discontinuities and late Intraluminal dismantling frequently observed.

Coronary artery double stenting techniques and their results in complex left main bifurcation disease

Aim: Complex left main (LM) bifurcation disease seems to be better approached by a planned double stent technique. Materials & methods: Medline search for articles including randomized trials, prospective series, large registries and retrospective studies >50 patients has been performed. Results: Double kissing crush demonstrated its superiority over culotte stenting and cross over, while other techniques such as the T-stenting and T-stent and Protrusion have not been extensively reported in LM setting. The nano inverted-T-stenting has provided evidences that the use of ultrathin strut stents and very minimal crush is beneficial for both the physiological and rheological properties. Conclusion: The double stenting techniques used in LM should be evaluated in terms of procedural differences and technical simplicity.

The impact of the extent of side branch disease on outcomes following bifurcation stenting

OBJECTIVES

To define the impact of side branch (SB) lesion length on clinical outcomes after percutaneous coronary intervention (PCI) on bifurcation lesions.

BACKGROUND

The role of the SB lesion length remains questionable in PCI planning and its implication on clinical outcome is controversial.

METHODS

Data from the retrospective multicenter EBC-P2BiTO registry were analyzed. The primary endpoint was the occurrence of major adverse cardiac events (MACE), defined as the composite of cardiac death, myocardial infarction excluding periprocedural, or stent thrombosis at 13 months median follow-up (IQR 11-28). By using propensity scores for inverse probability of treatment weighting (IPTW), the comparison of treatment groups was adjusted to correct for potential confounding.

RESULTS

Among 1,252 patients, SB was normal in 489 (39%), diseased in 763 (61%) cases. MACE occurred in 68 patients (5.4%). The optimal discriminant SB lesion length for MACE was ≥10 mm, with an area under the curve of 0.71 (p < .01). The incidence of MACE was higher among patients with SB lesions ≥10 mm (8%) than with normal SB (4.1%) (hazard ratio [HR], 2.8; 95% confidence interval [CI], 1.5-5.3; p = .001, IPTW-adjusted) or SB lesions <10 mm (5.1%) (HR, 1.5; 95% CI, 1.1-3.3; p = .048, IPTW-adjusted), being similar between these last two groups.

CONCLUSIONS

In bifurcation PCI, SB lesion length ≥ 10 mm identifies patients at higher risk of MACE than those with <10 mm SB lesions and those without SB disease, considering that no differences were observed among these last two groups. Careful planning is mandatory when approaching bifurcations with long SB lesions.

Comparison of Side-Branch Dilation Techniques After Resorbable Magnesium Scaffold Implantation: A Bench Study

BACKGROUND

The resorbable magnesium scaffold (RMS) has demonstrated a good safety profile to treat de novo lesions. Nevertheless, bifurcation lesions involving a side branch (SB) >2.0 mm in diameter were excluded from these studies, and such lesions remain technically challenging due to concerns of scaffold deformation or fracture. We sought to evaluate different SB dilation strategies after provisional T-stenting strategy with RMS using silicon bifurcation phantoms.

METHODS AND RESULTS

Three different strategies were compared: proximal optimization technique (POT)-side-rePOT (rePOT), kissing-balloon inflation (KBI), and mini kissing-balloon inflation (MKBI) strategies. Strut and connector fractures were evaluated by micro computed tomography and apposition by optical coherence tomography (OCT). Twelve Magmaris scaffolds (Biotronik) were successfully implanted (4 in each group). There was no difference in strut and connector fractures among the three techniques, as no fracture was visualized. OCT demonstrated that MKBI significantly decreased global malapposition following SB inflation as compared with rePOT or KBI strategies (95.3% vs 88.3% of perfectly apposed struts [P<.001] and 93.6% [P<.01], respectively, for MKBI vs rePOT and KBI). After step-by-step over-expansion of 6 RMS devices with 3.75 mm, 4.0 mm, and 4.5 mm NC balloons at 16 atm (ie, +1.5 mm from the initial 3.0 mm RMS), no strut or connector fracture could be visualized.

CONCLUSION

Provisional single-stent technique with the Magmaris RMS on a bifurcation lesion is technically feasible with these three different strategies without scaffold fracture. MKBI strategy resulted in better apposition rates as compared with KBI or rePOT strategies. Nevertheless, Magmaris use in bifurcation lesions should not be advised before similar results are confirmed by in vivo studies.

Necessity and proper way of intermediate kissing balloon dilation for culotte stenting: further insights from bench testing

Objective: The aim of this study was to investigate whether intermediate kissing balloon dilation (IKBD) is necessary during mini-culotte stenting (MCS) and how it can be properly conducted. Methods: MCS was emulated in a bifurcation model with a branch diameter difference (BDD) in three-step sizes of 0.50, 0.75 and 1.00 mm, and with intermediate balloon dilation (IBD) in three treatments of routine intermediate solo balloon dilation (rISBD), concurrent IKBD (cIKBD) or sequential IKBD. Microcomputed tomography was performed to assess stent under-expansion (SUE) around the polygon of confluence (POC), residual ostial stenosis (ROS) at the ostial side-branch (SB) and main-branch (MB) and stent cell distortion (SCD) in the bifurcation segments. Results: There were both main and interactive effects of IBD and BDD on ROS at the ostial SB and SCD in the ostial SB, but there were only main effects of IBD or BDD on SUE around the POC, ROS at the ostial MB and SCD in the ostial MB. Analysis of the main effects showed that SUE around the POC or ROS at the ostial SB was significantly different between sIKBD and rISBD and between cIKBD and rISBD. There was also a significant difference in SCD in the ostial SB between sIKBD and rISBD and between sIKBD and cIKBD. Analysis of the interactive effects showed that ROS at the ostial SB or SCD in the ostial SB was affected by all IBD treatments in all BDD step-sizes. Moreover, increasing the BDD step-sizes significantly increased ROS at the ostial SB as treated by rISBD and SCD in the ostial SB as treated by rISBD or cIKBD. Conclusions: SIKBD was shown to be essential and superior to rISBD or cIKBD, resulting in better bifurcated stent expansion and coverage when using MCS.

Concept and practice of transradial 5 French percutaneous treatment of coronary bifurcation lesions

OBJECTIVES

To assess the efficacy and safety of transradial 5 French percutaneous treatment of coronary bifurcations using conventional devices.

BACKGROUND

Radial artery is smaller than femoral artery, and its size may potentially limit transradial intervention, especially when coronary anatomy is not known.

METHODS

Patients with bifurcations lesions undergoing transradial 5 French ad hoc revascularization were treated according to provisional side branch (SB) stenting followed by the POT-SB dilation-final POT sequence. Only conventional devices were used.

RESULTS

Overall, 80 patients (58 men, 65 ± 10 years) were enrolled. True bifurcations accounted for 64% of cases, with the left anterior descending artery/diagonal branch being the most frequent bifurcation site (n = 37, 46%) and left main coronary artery bifurcation being treated in 6 (8%) patients. Angiographic success was achieved in 78 (97.5%) patients through a 5 French guiding catheter whereas in two cases, a 5-6 French guiding catheter upgrade was required to optimize SB treatment after the main bifurcation vessel have been secured. Overall, procedural success was achieved in all but one patient who had periprocedural necrosis following multivessel PCI. Another patient underwent target bifurcation revascularization because of a critical restenosis in a significant SB yielding an acute coronary syndrome five months after the index procedure.

CONCLUSIONS

This study demonstrates the feasibility of transradial 5 French bifurcation intervention with nondedicated devices and preliminary supports its efficacy and safety over a wide range of bifurcation anatomy and complexity.

Comparison of the planned one- and elective two-stent techniques in patients with coronary bifurcation lesions with or without acute coronary syndrome from the COBIS II Registry

OBJECTIVES

To evaluate the impacts of stent techniques on long-term clinical outcomes after percutaneous coronary intervention (PCI) using drug-eluting stents (DES) for coronary bifurcation lesions in patients with or without acute coronary syndrome (ACS).

BACKGROUND

Few studies have investigated the impacts of stent techniques for treating coronary bifurcation lesions in patients with and without ACS.

METHODS

This multicenter registry enrolled 2,897 patients undergoing PCI with DES for coronary bifurcation lesions. We investigated the impacts of planned one-stent and elective two-stent techniques in patients with (n = 1,798) and those without (n = 1,099) ACS. Primary endpoint was the incidence of 3-year target-lesion failure (TLF), defined as a composite of cardiac death, spontaneous myocardial infarction, and target-lesion revascularization.

RESULTS

The planned one-stent technique reduced TLF rate compared to elective two-stent technique in the ACS cohort (hazard ratio [HR] 0.49; 95% confidence interval [CI] 0.34-0.74; P = 0.001), and not in the non-ACS cohort (HR 0.61; 95% CI 0.35-1.06; P = 0.079). After propensity score matching, the planned one-stent technique had a significantly lower TLF rate (HR 0.47; 95% CI 0.29-0.74; P = 0.001) in patients with ACS, and it also showed a trend toward lower TLF rate with the planned one-stent technique in patients without ACS (9.0 vs. 14.5%, HR 0.59; 95% CI 0.32-1.14; P = 0.116).

CONCLUSIONS

Planned one-stenting reduced TLF in patients with ACS and it also might be beneficial in those without ACS for the treatment of coronary bifurcation lesions.

Elliptical stretch as a cause of side branch ostial compromise after main vessel stenting in coronary bifurcations: New insights from numerical analysis

BACKGROUND

The side branch (SB) compromise after main vessel (MV) stenting remains a significant problem in coronary bifurcation treatment. Currently the two major hypotheses for the mechanism of SB compromise are carina shift from MV into the SB and plaque shift into the ostium of side vessel. It is proposed herein, SB ostial deformation leading to reshaping of the ostium from circle to ellipse is a third possible mechanism. In the current study, the theoretical effects and correlation of ostial deformation with fractional flow reserve (FFR) is explored.

METHODS

Based on angiographic measurements and theoretical analysis formulas, three different SB ostial areas using circular ostial shape assumption and elliptical ostial shape assumption were calculated. Three different types of ostial areas with FFR values after MV stenting in 49 patients from the FIESTA registry were compared and analyzed.

RESULTS

It was found that there is significant overestimation of stenosis severity when estimated by the circle formula, than with the ellipse formula - ASc vs. ASds with 25% ± 13%, p < 0.001, ASc vs. ASmld with 9% ± 10%, p < 0.001. The elliptical shape assumptions provide more accurate ostial area stenosis, which correlates better with FFR. This finding is more significant in less severe stenosis (< 70% area stenosis) than in a more severe one.

CONCLUSIONS

A third possible mechanism of SB compromise after MV stenting of coronary bifurcation stenosis is elliptical ostial deformation at the ostium of SBs. The ostial area, calculated based on elliptical assumption correlates better with FFR, than area stenosis calculated with the traditional circular formula.

Impact of stent deformity induced by the kissing balloon technique for bifurcating lesions on in-stent restenosis after coronary intervention

OBJECTIVES

To investigate the impact of stent deformity induced by final kissing balloon technique (KBT) for coronary bifurcation lesions on in-stent restenosis (ISR).

BACKGROUND

In experimental models, the detrimental effects of KBT have been clearly demonstrated, but few data exists regarding the impact of proximal stent deformity induced by KBT on clinical outcomes.

METHODS

We examined 370 coronary lesions where intravascular ultrasound (IVUS)-guided second-generation drug-eluting stent (DES) implantation for coronary bifurcation lesions was performed. Based on IVUS analysis, the stent symmetry index (minimum/maximum stent diameter) and stent overstretch index (the mean of stent diameter/the mean of reference diameter) were calculated in the proximal main vessel.

RESULTS

The stent symmetry index was significantly lower (0.75 ± 0.07 vs 0.88 ± 0.06, P < 0.0001) and the stent overstretch index was significantly higher (1.04 ± 0.08 vs 1.01 ± 0.06, P = 0.0007) in lesions with KBT (n = 174) compared to those without KBT (n = 196). The number of two-stent technique in lesions with KBT was 31 (18%). In multivariate analysis, the degree of stent deformity indices was not associated with ISR in lesions with KBT; however, two-stent technique use was the only independent predictor of ISR at 8 months (hazard ratio: 3.96, 95% confidence interval: 1.25-12.5, P = 0.01).

CONCLUSIONS

Second-generation DES deformity induced by KBT was not associated with mid-term ISR.

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.

Optical coherence tomography to guide percutaneous treatment of coronary bifurcation disease

INTRODUCTION

Cardiovascular disease remains the most common cause of death worldwide. Enormous progress in the technology and applicability of percutaneous techniques to treat obstructive coronary heart disease has been made, and the number of percutaneous coronary interventions (PCI) is increasing. Coronary bifurcations are involved in a substantial number of PCIs and despite recent advances, bifurcation PCI remains a challenge in terms of immediate success and long-term outcome. Angiography has a limited capacity for showing important features of the 3 dimensional coronary vessel anatomy, position of stent struts and exact wire positions and is therefore suboptimal for guiding bifurcation PCI. Intracoronary optical coherence tomography (OCT) provides high resolution and the information gained during PCI is unprecedented compared with angiography guidance and intravascular ultrasound. Areas covered: This review will provide an overview of the use of OCT to guide bifurcation-PCI. Expert commentary: OCT is a promising guide for bifurcation-PCI at each individual step: from planning the strategy (provisional versus two-stent strategy), to guidance during PCI, and finally checking the interventional result. Until dedicated randomized trails are complete, we recommend OCT guidance for interventions in complex coronary bifurcation disease and for imaging when unexpected procedural events occur.

The impact of proximal cell rewiring compared with distal cell rewiring with single-stent deployment and subsequent kissing balloon inflation in the inadequate jailing of a Kaname stent on the side branch ostium

BACKGROUND

The aim of the study was to identify differences between proximal and distal cell rewir-ing with subsequent kissing balloon inflation (KBI) in the presence of a link connected to a carina on the jailed side branch ostium (SBO).

METHODS

Kaname stents were deployed in bifurcation models (n = 12) with subsequent KBI and were confirmed by optical coherence tomography. The jailing configuration and cell rewiring were completely controlled and classified as follows: FC-Dist, free carina (no links connected to a carina) and distal cell re-wiring; CC-Prox, connected to a carina (the presence of a link connected to a central carina) and proximal cell rewiring; CC-Dist, connected to a carina and distal cell rewiring; and FarDist, far-distal cell rewiring.

RESULTS

The number of frames with malapposed struts (MS) in the SBO was significantly smaller in the CC-Prox group than in the CC-Dist group (26.7 ± 1.5 and 39.7 ± 0.6, respectively, p < 0.05). The number of frames with MS continuously present from the distal end to the proximal side of the SBO was significantly smaller in the CC-Prox group than in the CC-Dist group (17.0 ± 2.0 and 36.7 ± ± 5.8, respectively, p < 0.05). The ratio of the maximal opened stent cell area to the SBO area was significantly larger in the CC-Prox group than in the CC-Dist group (64.2 ± 1.2% and 38.8 ± 5.6%, respectively, p < 0.05).

CONCLUSIONS

This study showed that in cases with a link connected to a carina, fewer malapposed struts may be present in proximal cell rewiring with subsequent KBI than in distal cell rewiring.

Complex bifurcation lesions: Randomized comparison of a fully bioresorbable modified t stenting strategy versus bifurcation reconstruction with a dedicated self-expanding stent in combination with bioresorbable scaffolds, an OCT study: Rationale and design of the COBRA II trial

OBJECTIVE

There is an ongoing controversy regarding the efficacy and safety of different percutaneous stenting techniques for coronary bifurcation lesions needing >1 stent. The promise of safe vessel restoration with bioresorbable scaffolds (BRS) may not be transferable to complex double BRS bifurcation techniques, and permanent metallic scaffolding of the bifurcation core may be needed. We identified modified-T stenting as the most promising fully bioresorbable 2-stent strategy in a preclinical setting. The objective of this study is to assess acute performance and compare long-term vessel healing with this strategy, versus an approach combining BRS with a dedicated metallic drug-eluting bifurcation stent.

STUDY DESIGN

In a single center, 60 consecutive patients with true and complex coronary bifurcation lesions will be randomly assigned to treatment with the dedicated self-expanding Axxess^™ biolimus-eluting bifurcation stent in the proximal main vessel and additional Absorb^™ everolimus-eluting BRS in the branches versus a modified T technique using Absorb^™ only. Angiography and optical coherence tomography (OCT) will be performed immediately after implantation and at 30 months, and clinical follow-up is foreseen up to 5 years after implantation. The primary endpoint is the change in minimal luminal area assessed with OCT from baseline to 30 months in pre-specified bifurcation segments.

CONCLUSION

To date the use of Absorb^™ BRS in complex coronary bifurcations has not been evaluated in a randomized clinical trial setting. The COBRA II study will examine the role and safety of a double BRS strategy in coronary bifurcations, alone or in combination with a metallic dedicated bifurcation device. © 2016 Wiley Periodicals, Inc.

Sequential Proximal Optimizing Technique in Provisional Bifurcation Stenting With Everolimus-Eluting Bioresorbable Vascular Scaffold: Fractal Coronary Bifurcation Bench for Comparative Test Between Absorb and XIENCE Xpedition

OBJECTIVES

The aim of this fractal bifurcation bench study was to compare provisional bifurcation stenting with a "re-POT" sequence, comprising a proximal optimizing technique (POT), side branch inflation, and final POT, between a bioresorbable vascular scaffold (BVS) and a metallic stent.

BACKGROUND

Re-POT proved significantly better than kissing balloon inflation in maintaining circular geometry without overstretch in metal stents, while significantly reducing side branch ostium strut obstruction and global strut malapposition. This should be useful for BVSs, which are more easily breakable.

METHODS

Twenty left main-like and 20 left anterior descending-like fractal coronary bifurcation bench models used 10 each 2.5 × 24 mm and 3.5 × 24 mm Absorb (Ab) BVSs and 10 each 2.5 × 24 mm and 3.5 × 24 mm XIENCE Xpedition (XX) metal stents, implanted by re-POT, with optical coherence tomographic analysis at each step and micro-computed tomographic analysis of Ab devices to detect strut fracture.

RESULTS

With Ab devices, re-POT reduced percentage strut malapposition close to XX rates (0.8 ± 0.7% vs. 0.0 ± 0.0%, p < 0.05; 3.5 ± 1.7% vs. 0.3 ± 0.6%, p < 0.05), conserving proximal circularity (elliptical ratio, 1.04 vs. 1.03 and 1.04 vs. 1.04; p = NS). Mean post-re-POT proximal expansion was 0.6 ± 0.1 mm (+21.6 ± 2.1%) for 2.5-mm and 1.0 ± 0.1 mm (+23.6 ± 2.2%) for 3.5-mm Ab devices, with only 1 strut fracture (left anterior descending-like bench). Side branch ostium strut obstruction was greater with Ab scaffolds than XX stents: 41.1 ± 9.4% versus 16.4 ± 8.1% (p < 0.05) and 31.8 ± 3.2% versus 10.0 ± 5.3% (p < 0.05), respectively, for 2.5- and 3.5-mm scaffolds and stents. Ab scaffolds showed 2 ± 1% moderate but significant late recoil as of 1 h, reaching 4 ± 2% by 24 h (p < 0.05).

CONCLUSIONS

Re-POT optimized most Ab provisional bifurcation treatments, without fracture, respecting fractal geometry, and without exceeding 1.0-mm proximal differential diameter.

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.

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

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

Single String Technique for Coronary Bifurcation Stenting: Detailed Technical Evaluation and Feasibility Analysis

OBJECTIVES

The study aimed to evaluate the adequacy and feasibility of the single string bifurcation stenting technique.

BACKGROUND

Double-stent techniques may be required for complex bifurcations. Currently applied methods all have their morphological or structural limitations with respect to wall coverage, multiple strut layers, and apposition rate.

METHODS

Single string is a novel method in which, first, the side branch (SB) stent is deployed with a single stent cell protruding into the main branch (MB). Second, the MB stent is deployed across this protruding stent cell. The procedure is completed by final kissing balloon dilation. The single string technique was first tested in vitro (n = 20) and next applied in patients (n = 11) with complex bifurcation stenoses.

RESULTS

All procedures were performed successfully, crossing a single stent cell in 100%. Procedure duration was 23.0 ± 7.9 min, and the fluoroscopy time was 9.4 ± 3.5 min. The results were evaluated by optical coherence tomography, showing fully apposed struts in 83.0 ± 9.2% in the bifurcation area. Residual area obstruction in the MB was 6.4 ± 5.6% and 25.0 ± 16.9% in the SB, as evaluated by micro computed tomography. All the human cases were performed successfully with excellent angiographic results: the residual area stenosis was 27 ± 8% and 29 ± 10% in the MB and in the SB, respectively, by 3-dimensional quantitative coronary angiography. No relevant periprocedural enzyme increase was observed. During follow-up (6 ± 4 months), no adverse clinical events (death, myocardial infarction, target vessel revascularization) were noted.

CONCLUSIONS

The single string technique for complex bifurcation dilation was shown to be adequate in vitro and feasible in humans, with favorable results in terms of stent overlap, malapposition rate, and low residual obstruction in both the MB and SB.

A new stenting technique for bifurcation lesions a nine-patient case series

AIMS

This study describes and reports preliminary outcomes using kissing T-stenting and small protrusion (K-TAP), a novel modification of traditional T-stenting and small protrusion (TAP).

METHODS AND RESULTS

Nine patients who were treated with K-TAP between May 2008 and February 2012 at two hospitals were retrospectively included in this study. The primary endpoints were angiographic success, procedural success, and the composite 30-day and long-term occurrences of major adverse cardiac events (MACEs), which consisted of death, coronary artery bypass graft surgery, repeated percutaneous coronary intervention of the target vessel, and non-Q-wave and Q-wave myocardial infarctions. Data were obtained from the review of institutional databases, folder auditing, a telephone survey of the patients, and the review of angiograms. Angiographic success and procedural success were achieved in all patients. The mean fluoroscopy time for the total procedure was 24.1 min (range 20-28). No complications occurred during the procedures. The MACE rate during the mean follow-up period of 102 weeks (range 22-196 weeks) was 0%.

CONCLUSIONS

K-TAP, a new coronary bifurcation stenting method, has favorable angiographic and procedural success rates and a low early post-procedure MACE rate. Further studies are needed to evaluate the clinical efficacy of the K-TAP method.

The Role of Bioresorbable Scaffolds in Meeting the Challenges of Bifurcations

Side branches are frequently related to periprocedural complications. Considering any side branches >1 millimetres (mm), side branch occlusion or reduced flow may occur in approximately 10 % of interventional procedures. First data indicate that bioresorbable vascular scaffolds (BVS) behave similar compared with modern drug-eluting stents (DES) with regard to compromising or occluding sizeable side branches. Although technically more demanding compared with modern DES, it appears to be feasible to dilate side branches after crossing BVS cells. Preliminary data suggest at least balloon diameters up to 2.5 mm can be used, but safety remains unclear. Instead of kissing balloon dilatation, rather sequential balloon dilatation should be employed. Anecdotic evidence suggests BVS can be used even in relatively complex coronary anatomy, e.g. bifurcations distal to chronic total occlusion. Certainly more data are needed. As of today, BVS offer promise not only for the treatment of simple coronary lesions but also bifurcations. Given successful side branch protection, they might allow for restoring the native coronary anatomy in the sense of restitutio ad integrum.

Single-stent crossover technique from distal unprotected left main coronary artery to the left circumflex artery

OBJECTIVES

To report the clinical outcomes of single-stenting from distal unprotected left main coronary artery (LMCA) to the left circumflex artery (LCx).

BACKGROUND

Percutaneous coronary intervention of distal LMCA is usually performed by stenting into the left anterior descending artery (LAD). In some cases, stenting from LMCA to LCx alone is performed.

METHODS

Between April 2002 and April 2011, single-stenting with drug-eluting stents for distal unprotected LMCA disease was performed in 584 patients. Thirty-one patients underwent LMCA-LCx stenting, who were compared with the remaining 553 LMCA-LAD stented patients.

RESULTS

At 3-year follow-up, there were no significant differences between LMCA-LCx and LMCA-LAD stenting groups in major adverse cardiac events (24.1% vs. 19.6%; P = 0.540), cardiac death, and myocardial infarction. A trend toward higher target lesion revascularization (TLR) in the LMCA-LCx stenting group was noted. This was significant when the stented branch was only considered (18.2% vs. 3.0%; P < 0.001). In both TLR subgroups, LCx ostium was frequently involved (83.3% in LMCA-LCx vs. 66.2% in LMCA-LAD TLR subgroups; P = 0.39). The LAD ostium was more frequently involved in LMCA-LCx TLR subgroup (83.3% vs. 21.0%; P < 0.001). On the multivariable Cox regression analysis, LMCA-LCx stenting was an independent predictor of TLR for restenosis at the ostium of the stented branch (HR 6.49; 95% CI 2.27-18.53; P < 0.001).

CONCLUSIONS

TLR rate at the LCx ostium is high irrespective of LMCA-LCx or LMCA-LAD stenting. The former also seems to be associated with high TLR at the LAD ostium. It may therefore be important to evaluate alternative strategies for treating distal LMCA disease that extends into the LCx but not LAD.

Computational fluid dynamic simulations of image-based stented coronary bifurcation models

One of the relevant phenomenon associated with in-stent restenosis in coronary arteries is an altered haemodynamics in the stented region. Computational fluid dynamics (CFD) offers the possibility to investigate the haemodynamics at a level of detail not always accessible within experimental techniques. CFD can quantify and correlate the local haemodynamics structures which might lead to in-stent restenosis. The aim of this work is to study the fluid dynamics of realistic stented coronary artery models which replicate the complete clinical procedure of stent implantation. Two cases of pathologic left anterior descending coronary arteries with their bifurcations are reconstructed from computed tomography angiography and conventional coronary angiography images. Results of wall shear stress and relative residence time show that the wall regions more prone to the risk of restenosis are located next to stent struts, to the bifurcations and to the stent overlapping zone for both investigated cases. Considering a bulk flow analysis, helical flow structures are generated by the curvature of the zone upstream from the stent and by the bifurcation regions. Helical recirculating microstructures are also visible downstream from the stent struts. This study demonstrates the feasibility to virtually investigate the haemodynamics of patient-specific coronary bifurcation geometries.