Contemporary techniques in percutaneous coronary intervention for bifurcation lesions

Drug Coated Balloon in the Treatment of De Novo Coronary Artery Disease: A Narrative Review

Drug coated balloons (DCBs) are currently indicated in guidelines as a first choice option in the management of instant restenosis, whereas their use in de novo lesions is still debated. The concerns raised after the contrasting results of the initial trials with DCBs in de novo lesions have been more recently overcome by a larger amount of data confirming their safety and effectiveness as compared to drug-eluting stents (DES), with potentially greater benefits being achieved, especially in particular anatomical settings, as in very small or large vessels and bifurcations, but also in selected subsets of higher-risk patients, where a 'leave nothing behind' strategy could offer a reduction of the inflammatory stimulus and thrombotic risk. The present review aims at providing an overview of current available DCB devices and their indications of use based on the results of data achieved so far.

Influence of different postballoon expansion procedures: A finite element analysis

BACKGROUND

Postballoon expansion is considered as an appropriate procedure for adequate stent expansion for coronary bifurcation lesions. Two postballoon expansion procedures are currently recommended: proximal optimization technique (POT)/side/POT and POT/kiss/POT. However, the effects of the two postballoon expansion treatments are different. There is a lack of biomechanical study to quantify the difference.

PURPOSE

It is recognized that biomechanical factors influence the occurrence of Major Cardiovascular Adverse Events (MACE), which includes recurrent angina pectoris, acute myocardial infarction and coronary heart disease death. The current paper evaluated the two postexpansion strategies and quantified biomechanical parameters to provide a basis for clinical decisions.

METHODS

Based on the CT angiography (CTA) data of a patient diagnosed with coronary bifurcation lesions, a personalized coronary bifurcation lesion model was constructed, and the surgical procedure after two expansions was simulated. The POT/side/POT and POT/kiss/POT expansion procedures were analyzed from the perspective of biomechanics through finite element analysis. The biomechanics factors, including the percentage of stent malapposition and stent occlusion at the side branch (SB) opening, the stent ellipse index of proximal main vessel (PMV) segment, the minimum lumen area of the stent vessel segment and the stress distribution of the vessel wall, were used to quantify clinician concerns about factors affecting patient outcomes. The factors include stent adhesion, SB open stent occlusion, poor stent deformation, patency effect of vessel stenosis, and vessel wall damage.

RESULTS

Both postexpansion procedures were successfully simulated. The malapposition rate during POT/side/POT was larger (1.2% vs. 0.42%) and stent occlusion at the SB opening from the cross-section perpendicular to the SB opening after the POT/side/POT procedure was 0.20%, compared with 0.00% after POT/kiss/POT. POT/kiss/POT produced a larger PMV segment stent ellipse index. Minimum lumen area after POT/side/POT was 5.6 mm² and after POT/kiss/POT 5.9 mm² . POT/kiss/POT produces an effect of greater vascular stress than POT/side/POT.

CONCLUSION

Numerical simulations provide a quantitative analysis to inform clinicians of the differences between preoperative planning and surgical procedures. Biomechanical analysis of the differences between the two postexpansion strategies found that the POT/kiss/POT procedure resulted in better stent fit, less occlusion of the SB open stent and better vascular patency but also resulted in poor stent deformation and caused greater vessel wall stress. The current study informs rationales for clinical understanding of postexpansion strategies.

Protective ballooning technique for prevention of side branch occlusion in coronary nonleft main true bifurcation lesions: A single-center study

OBJECTIVES

We aimed to evaluate the efficacy of a protective ballooning technique in preventing side branch (SB) occlusion and to assess the long-term clinical outcomes for coronary nonleft main true bifurcation lesions.

BACKGROUND

SB occlusion is a major complication associated with percutaneous coronary intervention (PCI) for coronary bifurcation lesions.

METHODS

Patients were consecutively enrolled and randomly assigned to protective ballooning technique or jailed wire technique group. Periprocedural and long-term clinical outcomes were compared.

RESULTS

Patients in the protective ballooning technique (n = 173) and jailed wire technique (n = 167) groups were followed up for 12 months. SB occlusion occurred in one patient (0.6%) and nine patients (5.4%) in each group, respectively. The proportion of thrombolysis in myocardial infarction (TIMI) flow grade 3 of the SB was higher in the protective ballooning technique group (98.8% vs. 95.2%, p < 0.05). SB rewiring was necessary in one patient in the protective ballooning technique group (0.6%) with provisional stenting, significantly lower than that in the jailed wire technique group (seven patients, 4.2%; p = 0.03). Periprocedural myocardial infarction occurred in three (1.73%) and six (3.59%) patients in the protective ballooning technique and jailed wire technique groups without significant difference, respectively. Major adverse cardiovascular events at 12 months were similar in both groups.

CONCLUSIONS

Protective ballooning technique is effective for the prevention of SB occlusion in nonleft main true bifurcation lesions and had favorable long-term outcomes at the 12-month follow-up.

Drug coated balloons for coronary artery bifurcation lesions: A systematic review and focused meta-analysis

Objectives

We sought to systematically review the evidence supporting the role of drug coated balloons (DCBs) in the treatment of coronary bifurcation lesions.

Background

DCBs are emerging as an attractive alternative treatment strategy for treating coronary bifurcations due to simplifying the approach and reducing rates of stent related complications. We systematically reviewed the evidence for DCB use in coronary bifurcations and conducted a focused meta-analysis on late lumen loss in the side branch comparing DCB and plain old balloon angioplasty (POBA).

Methods

This study was conducted in line with the PRISMA statement. All studies (including both RCTs and observational studies, excluding case reports) using DCB as part of a bifurcation strategy were included in this review. A literature search identified a total of ten studies for inclusion. A focused meta-analysis was undertaken for the use of DCB in side-branch compared with POBA. Mean late lumen loss was used with a random effects model due to heterogeneity.

Results

DCB was found to be superior to POBA for side branch treatment in bifurcations (p = 0.01). There are four studies that investigated the use of DCB for main branch treatment in a bifurcation, with evidence supporting its safety in main branches of bifurcation lesions, while prospective observational studies have demonstrated favourable target lesion revascularisation rates.

Conclusion

Although there is a lack of robust RCTs comparing DCBs with current generation DES, DCBs appear safe in main branch bifurcation lesions with improved side branch late lumen loss when compared with DES or POBA.

A Novel guide extension assisted stenting technique for coronary bifurcation lesions

A challenging technical scenario frequently encountered in a percutaneous coronary intervention of a coronary bifurcation lesion (CBL) is stent implantation of only the stenosed segment without compromising the other two normal segments in non-true bifurcation lesions. Another is precise stent implantation covering the side branch ostium without leaving excessive stent metal at the other two segments of a bifurcation lesion in complex true bifurcation lesions. The aim of this study was to describe a novel stenting technique for both non-true and true CBLs by using a guide extension catheter (GuideLiner). With the assistance of a guide extension catheter mounted on both the main and the side-branch guidewires and with its intubation down to the bifurcation carina, a stent can be implanted in the side branch segment or distal main segment of the bifurcation lesion appropriately without compromising the other two segments of the coronary bifurcation. Stent implantation is described in three bifurcation lesions in three cases and shown in detail with illustrative figures. The technique facilitates side-branch only stenting in side-branch mono-ostial (medina 0, 0, 1) CBL or only the distal main segment in distal mono-ostial (medina 0, 1, 0) CBL without compromising the other two remaining segments when using the one-stent technique in non-true CBLs without leaving unnecessary excessive stent metal at the bifurcation site and when using a two-stent technique in complex true bifurcation lesions (tri-ostial or medina 1, 1, 1). Consequently, through optimizing stent deployment, the technique may have the potential to reduce the risk of subacute stent thrombosis and future in-stent restenosis. The most appropriate lesions suitable for the technique, and some other practical tips are also described.

Role of IVUS in the rectification of angiographically judged ramus intermedius and its clinical significance

Background

Due to the technical limitations of coronary artery angiography (CAG), ramus intermedius (RI) is sometimes difficult to distinguish from a high-origin obtuse marginal branch or a high-origin diagonal branch. This study sought to investigate the role of intravascular ultrasonography (IVUS) in the rectification of angiographically judged RI.

Methods

This study retrospectively analyzed 165 patients who were reported to have an RI based on CAG and underwent IVUS implementation from 02/01/2009 to 31/12/2019 in Zhongshan Hospital, Fudan University. Taking IVUS as the gold standard, we calculated the accuracy of RI identification by CAG and evaluated the impact of RI on revascularization strategy.

Results

Among the 165 patients, 89 patients (54%) were demonstrated to have an RI on IVUS (IVUS-RI), 32 patients (19%) were identified to have a high-origin diagonal branch on IVUS (IVUS-h-D), and 44 patients (27%) had an actual high-origin obtuse marginal artery on IVUS (IVUS-h-OM). Among 84 patients who underwent one-stent crossover stenting because of left main furcation lesions (48 patients in the IVUS-RI group, 12 patients in the IVUS-h-D group, and 24 in the IVUS-h-OM group), 14.6% of patients in the IVUS-RI group, 33.3% in the IVUS-h-D group and 0% in the IVUS-h-OM group had CAG-RI compromise (P = 0.02), which was defined as severe stenosis of the RI ostium (> 75%) or significant RI flow impairment (TIMI < 3).

Conclusions

Only 54% of CAG-RIs were confirmed by IVUS, which indicates the necessity of preintervention IVUS to distinguish real RIs from other branches in LM furcation lesions.

Influence of Stent Flexibility on Artery Wall Stress and Wall Shear Stress in Bifurcation Lesions

Purpose

Stent flexibility can influence clinical outcome, especially in bifurcation lesions. For instance, an overly rigid stent can impose mechanical stress on the artery at the stent edges and alter both arterial geometry and blood flow dynamics in bifurcations. This study investigated the influence of stent flexibility on vessel geometry, histology, wall stress, and blood flow dynamics in arterial bifurcations.

Materials and Methods

We compared arterial angulation, stenosis, histopathology, simulated wall shear stress (WSS), and simulated blood flow velocity distribution in swine coronary artery bifurcations following placement of the less flexible Multi-link 8 or more flexible Kaname stent (4.1 ± 0.5 vs 1.5 ± 0.1 mN, p < 0.05, t-test). Stents were implanted into six coronary artery bifurcations each using the single-stent crossover technique without side branch strut dilatation. Outcomes were examined after 28 days.

Results

Implantation of both stents significantly increased site angulation (Multi-link 8: 148° ± 8° to 172° ± 2°, p < 0.05, paired t-test; Kaname: 152° ± 5° to 164° ± 4°, p < 0.05, paired t-test), but the change tended to be greater after Multi-link 8 stent implantation (24° ± 15° vs 11° ± 7°, p = 0.1, t-test), suggesting greater straightening of the bifurcation. The Multi-link 8 stent induced greater neointimal thickness than the Kaname stent (0.53 ± 0.3 mm vs 0.26 ± 0.1 mm, p < 0.05, t-test). The distribution of neointimal hyperplasia following stent implantation as revealed by longitudinal histopathology matched the distribution of WSS simulated using computational fluid dynamics (CFD). The endothelium at low WSS areas exhibited aberrant cell morphology and leukocyte adhesion. A CFD model of a curved bifurcation suggested that the region of low WSS is expanded by artery straightening.

Conclusion

In bifurcated lesions, stent flexibility influences not only mechanical stress on the artery but also WSS, which may induce local neointimal hyperplasia.

Drug coated balloons and their role in bifurcation coronary angioplasty: appraisal of the current evidence and future directions

INTRODUCTION

Coronary Bifurcation lesions are technically more challenging and Bifurcation percutaneous coronary intervention (PCI) remains a challenge with unpredictable and sub-optimal clinical and angiographic results. Drug-Coated Balloons (DCB) are emerging devices in the field of coronary intervention with promising results that may overcome some of drug eluting stents limitations and may have potential advantages in complex bifurcation PCI.

AREAS COVERED

We have performed a re-appraisal about the issues with current bifurcation PCI techniques and the use of DCB in the treatment of Bifurcation lesions. Several studies performed utilizing DCB are described and critically appraised. Over the recent years, there have been tremendous developments in the DCB technology, lesion preparation, clinical experience, and clinical data during bifurcation PCI. The current review describes the advances in the DCB technology, pharmacokinetics, role of excipients, and optimization of the technique. Special emphasis in lesion preparation and potential pathway of using DCB in bifurcation PCI is proposed.

EXPERT OPINION

Although different proof of concept and pilot studies have shown promising results in treatment of bifurcation lesions with DCB, larger randomized trials and/or international consensus papers are required to enable worldwide translation of this idea to clinical practice.