Final kissing balloon inflation by classic crush stenting did not improve the clinical outcomes for the treatment of unprotected left main bifurcation lesions: The importance of double-kissing crush technique

Coronary Bifurcation Stenting: Review of Current Techniques and Evidence

BACKGROUND

Coronary bifurcation stenting constitutes 20% of all PCI performed. Given the extensive prevalence of bifurcation lesions, various techniques have sought to optimally stent the bifurcation to improve revascularization while also decreasing rates of stent thrombosis and lesion recurrence. Advanced techniques, such as planned two-stent approaches, have been shown to have improved outcomes but also require fluoroscopy and procedure time, posing an economic argument as well as a patient-outcome one.

OBJECTIVE

Because of the many strategies posited in the literature, it becomes essential to objectively evaluate evidence from randomized controlled trials and meta-analyses to help determine the optimal stenting strategy.

METHODS

We reviewed the clinical evidence on the efficacy of coronary bifurcation stenting.

RESULTS

In this paper, we review the most recent randomized controlled trials and meta-analyses on the efficacy of various stenting techniques and advances in stenting technologies published to gauge the current state of understanding and chart where the field is heading.

CONCLUSION

Bifurcation stenting is a maturing problem in the field of interventional cardiology that is adapting to the needs of the patients and advances in technology.

Percutaneous coronary intervention of bifurcation lesions

Bifurcation coronary artery disease is common as the development of atherosclerosis is facilitated by altered endothelial shear stress. Multiple anatomical and physiological factors need to be considered when treating bifurcation lesions. To achieve optimal results, various stenting techniques have been developed, each with benefits and limitations. In this state-of-the-art review we describe technically important characteristics of bifurcation lesions and summarise the evidence supporting contemporary bifurcation techniques.

Clinical Implications of Bifurcation Angles in Left Main Bifurcation Intervention Using a Two-Stent Technique

Objectives

The aim of this study was to assess the clinical impact of 3 bifurcation angles in left main (LM) bifurcation treated with the 2-stent technique.

Background

Data are limited regarding the impact of bifurcation angles after LM percutaneous coronary intervention (PCI).

Methods

Using patient-level 4 multicenter registries in Korea, 462 patients undergoing LM bifurcation PCI with the 2-stent technique were identified (181 crush, 167 T-stenting; 63% 1^st generation drug-eluting stent (DES), 37% 2^nd generation DES). Three bifurcation angles, between the LM and left anterior descending (LAD), the LM and left circumflex (LCX), and the LAD and LCX, were measured. The primary outcome was target lesion failure (TLF), a composite of cardiac death, myocardial infarction, and target lesion revascularization (TLR).

Results

In patients treated with the crush technique, the best cutoff value (BCV) to predict TLF was 152° of the LM-LAD angle. In the crush group, a significantly higher TLF rate, mostly driven by TLR, was observed in the LM-LAD angle ≥152° group compared with the <152° group (35.7% vs. 14.6%; adjusted hazard ratio 3.476; 95% confidence interval 1.612–7.492). An LM-LAD angle ≥152° was an independent predictor of TLF. In the T-stenting, no bifurcation angle affected the clinical outcomes.

Conclusions

In LM bifurcation PCI using the 2-stent technique, wide LM-LAD angle (≥152°) was associated with a greater risk of TLF in the crush, whereas none of the bifurcation angles affected T-stenting outcomes.

Feasibility of a Porcine Arteriovenous Shunt Model for Assessment of Acute Thrombogenicity in Bifurcation Stenting Technique By Optical Coherence Tomography

BACKGROUND

Double kissing (DK) crush stenting has been reported as a superior bifurcation stenting strategy compared to culotte stenting. However, the mechanism associated with the reduction of clinical events by DK crush stenting remains unclear. We therefore investigated the thrombogenicity of DK crush stenting and culotte stenting with both bare-metal stents (BMS) and drug-eluting stents (DES) and the feasibility of a novel porcine arteriovenous shunt model.

METHODS

High-resolution intracoronary imaging with optical coherence tomography (OCT) evaluated the bifurcation stenting models for thrombogenicity.

RESULTS

All porcine models retained continuous circulation without blood leakage. Thrombus was macroscopically demonstrated around the bifurcation in all settings. The volume of thrombus (mm³) with BMS using DK crush/culotte and DES using DK crush/culotte were 1.38/1.19 and 0.09/0.15, respectively. Culotte stenting had more thrombus in the proximal main branch, and DK crush stenting had more at the bifurcation. Unlike DK crush stenting, culotte stenting showed malapposition in the proximal main branch and bifurcation segments.

CONCLUSION

The feasibility of a porcine arteriovenous shunt model to assess thrombogenicity by OCT in bifurcation stenting technique was confirmed. OCT detected less thrombogenicity in DES when used in the bifurcation model when compared to BMS.

Anatomic features of the left main coronary artery and factors associated with its bifurcation angle: a 3-dimensional quantitative coronary angiographic study

OBJECTIVE

To assess the anatomic characteristics of the left main coronary artery (LM), and the relation between anatomic and clinical factors and the LM bifurcation angle (BA) using a novel, three dimensional quantitative coronary angiography (3D QCA) software.

BACKGROUND

Percutaneous intervention of the LM is a therapeutic option in selected patients with coronary artery disease (CAD). The anatomic features of the LM and its BA are determinants of procedural success and clinical outcome. However, those features and the factors that may affect the LM BA have not been fully described.

METHODS

The LM anatomy was evaluated from angiograms of 203 patients (age = 66 ± 11 years, 31% female) with and without LM CAD using 3D QCA analysis (IC-PRO, Paieon, Israel). LM size as well as the proximal BA (between LM and LCX) and the distal BA (between left anterior descending coronary artery (LAD) and left circumflex coronary artery (LCX)) were measured in end-diastole. Angiographic and clinical findings were also recorded.

RESULTS

133/203 patients (65%) had no LM CAD. 3D QCA analysis demonstrated significant variability in the anatomy of the normal LM, including the LM branch vessels (LAD, LCX) diameter, and the LM BA. Among the 70 patients with LM CAD, 44 had distal LM disease. Importantly, patients with distal LM CAD had narrower proximal BA and a wider distal BA. Multivariate analysis (adjusted for clinical and anatomic variables) identified female sex (P = 0.02), trifurcation anatomy (P = 0.009), age > 75 years (P = 0.0009), and LM length > 12 mm (P = 0.001) as independent associates of the proximal BA. Independent associates of the distal BA were: trifurcation anatomy (P = 0.001), LM length > 12 mm (P < 0.0001), age > 75 years (P = 0.004), and a history of coronary bypass surgery (P = 0.04).

CONCLUSIONS

The current study demonstrates significant variability in the anatomy of the LM. The LM BA differs between patients with and without distal LM CAD, and both anatomic and clinical factors may affect the LM BA. Our findings also emphasize the possible usefulness of 3D QCA in the assessment of the LM.

Is there a higher risk of stent thrombosis in bifurcation lesion or is it related to the technique?

Bifurcation lesions and bifurcation stenting have been reported to be risk factors of stent thrombosis (ST). ST is a complex process that may be the culmination of device, patient, lesion and procedural factors. The strategy of provisional SB stenting is widely accepted for suitable bifurcation lesions, and is accompanied by low rates of ST. However, it is not applicable to all patients, and in these clinical scenarios (approx. 10%), there is no consensus on the best option for elective stenting with two stents regarding the incidence of ST. Excessive metal scaffolding, such as in the classical crush technique, should be avoided. Further accumulation of long-term data from larger clinical registries and randomised studies will be needed to elucidate the best technique regarding the avoidance of ST in bifurcation treatment. Dedicated bifurcation stents tailored for each type of lesion could resolve this issue, especially the excess of metal protruding in the vessel lumen or crushed onto the wall. However, they need to be tested in upcoming and ongoing trials. Stent thrombosis (ST) is the sudden occlusion of a stented coronary artery due to thrombus formation. Despite major improvements of antiplatelet therapy, thrombotic events remain the primary cause of death after percutaneous coronary interventions (PCI). The clinical consequences of ST are frequently catastrophic and include death in 20% to 48% or major myocardial infarction (MI) in 60% to 70% of the cases. In the drug-eluting stent era, ST and especially very late ST remains a concern of coronary intervention. Bifurcation lesions and bifurcation stenting have been reported to be the risk factors for ST. ST is a complex process that may be a culmination of device, patient, lesion, and procedural factors. The exact cause of the higher risk of ST in bifurcation lesions is unknown although pathologic studies have suggested that the arterial branch points are predisposed to development of atherosclerotic plaque, thrombus, and inflammation because they are foci of low shear stress.

Comparing two-stent strategies for bifurcation coronary lesions: which vessel should be stented first, the main vessel or the side branch?

This study compared two-stent strategies for treatment of bifurcation lesions by stenting order, 'main across side first (A-family)' vs 'side branch first (S-family). The study population was patients from 16 centers in Korea who underwent drug eluting stent implantation with two-stent strategy (A-family:109, S-family:140 patients). The endpoints were cardiac death, myocardial infarction (MI), stent thrombosis (ST), and target lesion revascularization (TLR) during 3 years. During 440.8 person-years (median 20.2 months), there was 1 cardiac death, 4 MIs (including 2 STs), and 12 TLRs. Cumulative incidence of cardiac death, MI and ST was lower in A-family (0% in A-family vs 4.9% in S-family, P = 0.045). However, TLR rates were not different between the two groups (7.1% vs 6.2%, P = 0.682). Final kissing inflation (FKI) was a predictor of the hard-endpoint (hazard ratio 0.061; 95% CI 0.007-0.547, P = 0.013), but was not a predictor of TLR. The incidence of hard-endpoint of S-family with FKI was comparable to A-family, whereas S-family without FKI showed the poorest prognosis (1.1% vs 15.9%, retrospectively; P = 0.011). In conclusion, 'A-family' seems preferable to 'S-family' if both approaches are feasible. When two-stent strategy is used, every effort should be made to perform FKI, especially in 'S-family'.

Crush stenting with drug-eluting stents: relevance of coronary bifurcation lesion location on angiographic and clinical outcomes

BACKGROUND

Data on the relevance of the location of coronary bifurcation lesions treated by crush stenting with outcomes were limited.

HYPOTHESIS

We hypothesized that the location of the bifurcation lesion correlated with clinical outcome.

METHOD

A total of 212 patients with 230 true bifurcation lesions treated by crush stenting with drug-eluting stents (DES) were assessed prospectively. Surveillance quantitative angiographies were indexed at 8 months after procedure. Primary endpoint was major adverse cardiac events (MACE), defined as cardiac death, myocardial infarction, and target lesion revascularization (TLR).

RESULTS

Patients in the distal right coronary artery (RCAd) group were characterized by higher proportions of prior myocardial infarction and very tortuous lesions. However, lesions in the RCAd group, compared to those of other groups, had the lowest late lumen loss, with resultant lowest incidence of MACE at a mean follow-up of 268±35 days. Independent predictors of MACE included unsatisfied kissing (KUS; hazard ratio [HR]: 12.14, 95% confidence interval [CI]: 4.01-12.10, P = .001) and non-RCA lesion (HR: 20.69, 95% CI: 5.05-22.38, P = .001), while those of TLR were KUS (HR: 10.21, 95% CI: 0.01-0.34, P = .002), bifurcation angle (HR: 4.728, 95% CI: 2.541-4.109, P = .001), and non-RCA lesion (HR: 16.05, 95%CI: 1.01-4.83, P = .001).

CONCLUSIONS

Classical crush stenting with drug-eluting stents is associated with significantly better outcomes in RCAd. Quality of kissing inflation is mandatory to improve outcome.

Coronary left main and non-left main bifurcation angles: how are the angles modified by different bifurcation stenting techniques?

BACKGROUND

Investigation of the correlation between bifurcation angles and outcomes is limited with discordant results. The aim of this study is to investigate left main (LM) and non-left main (N-LM) bifurcation angles and their modification after percutaneous coronary intervention (PCI). Measurement of all three angles adds to our understanding of bifurcation anatomy and the resultant effect of different stenting techniques.

METHODS AND RESULTS

All three bifurcation angles were described according to the European Bifurcation Club definition: the A (proximal bifurcation angle), the B (distal bifurcation angle) and the C (main branch angle). Measurements were performed in 75 LM and 140 N-LM bifurcations. In LM bifurcations baseline mean values of C, A, and B were 151 degrees +/- 28 degrees, 131 degrees +/- 32 degrees, and 78 +/- 28 degrees, respectively. In bifurcations with 2 stents the B significantly decreased by a mean of 10 degrees (P = 0.003) and A increased by 10 degrees (P = 0.006). Crush stenting significantly decreased B (A - 14 degrees ; P = 0.020) and increased A (A + 21 degrees; P = 0.005), particularly non-true bifurcations. In N-LM bifurcations mean values for C, A, and B were 156 degrees +/- 19 degrees , 144 degrees +/- 22 degrees, and 60 degrees +/- 20 degrees, respectively. Similar to LM bifurcations, the B became narrower mainly at the expense of the A, which became wider. In both types of bifurcations the greatest variation in A and B was found following 2-stent techniques performed in T-shaped (> or =70 degrees) bifurcations.

CONCLUSIONS

In both LM and N-LM bifurcations we found a significant difference in A and B pre- and post-PCI. This difference was driven by the 2-stent technique and was most evident with a baseline bifurcation angle > or =70 degrees. The Crush technique caused the largest angle variation post-procedure, particularly in non-true LM bifurcations.

3-Dimensional bifurcation angle analysis in patients with left main disease: a substudy of the SYNTAX trial (SYNergy Between Percutaneous Coronary Intervention with TAXus and Cardiac Surgery)

OBJECTIVES

We explore the bifurcation angle (BA) parameters of the left main coronary artery (LM), the effect of percutaneous coronary intervention (PCI) on this angulation, and the impact of BA on clinical outcome.

BACKGROUND

The BA is emerging as a predictor of outcome after PCI of bifurcation lesions. Three-dimensional (3D) quantitative coronary angiography (QCA) overcomes the shortcomings of 2-dimensional analysis and provides reliable data.

METHODS

This is a substudy of the SYNTAX (SYNergy Between Percutaneous Coronary Intervention With TAXus and Cardiac Surgery) trial. The cineangiograms of the 354 patients who underwent PCI of their LM stem were analyzed with 3D QCA software (CardiOp-B, Paieon Medical, Ltd., Rosh Ha'ayin, Israel). The proximal BA (between LM and left circumflex [LCX]) and the distal BA (between left anterior descending and LCX) were computed in end-diastole and end-systole, both before and after PCI. The cumulative major adverse cardiac and cardiovascular event (MACCE) rates throughout the 12-month period after randomization were stratified across pre-PCI distal BA values and compared accordingly.

RESULTS

Complete analysis was feasible in 266 (75.1%) patients. Proximal and distal BA had mean pre-PCI end-diastolic values of 105.9 +/- 21.7 degrees and 95.6 +/- 23.6 degrees , respectively, and were inversely correlated (r = -0.75, p < 0.001). During systolic motion of the heart there was an enlargement of the proximal angle and a reduction of the distal angle (DeltaBA -8.2 degrees and 8.5 degrees , respectively, p < 0.001 for both). The PCI resulted in a mean decrease in the distal BA (DeltaBA 4.5 degrees , p < 0.001). The MACCE rates did not differ across distal BA values; freedom from MACCE at 12 months was 82.8%, 85.4%, and 81.1% (p = 0.74) for diastolic values (first through third tertile).

CONCLUSIONS

Left main BA analysis with 3D QCA is feasible. Both proximal and distal angles are affected by cardiac motion; PCI modifies the distal angle. There is no clear difference in event rates across pre-PCI distal BA values.

[Update on interventional cardiology]

Percutaneous intervention, whether coronary or noncoronary, continues to be a highly active area of medicine. This article contains an overview of the most notable developments reported in recent months. Drug-eluting stents (DESs) have provided one of the major advances in interventional cardiology as they have very effectively reduced the restenosis rate. Both randomized clinical trials and large observational studies have confirmed their safety, and their use has been extended to include highly complex conditions. Although thrombosis is one complication that can affect both conventional stents and DESs, the rate of late stent thrombosis is slightly, though significantly, higher with DESs. Primary angioplasty is the treatment of choice for patients with acute myocardial infarction if carried out under appropriate conditions, within a reasonable time period in a specialized center by experienced personnel. Use of thrombectomy devices can improve procedural outcomes and it appears that DES implantation is safe and effective, though more data are still needed. In patients with non-ST-elevation acute coronary syndrome, early treatment using an invasive approach coupled to the administration of various combinations of antiplatelet and antithrombotic drugs continues to be fundamental. Although left main coronary artery lesions are generally treated surgically, advances in percutaneous techniques and the use of DESs mean that an increasing number of patients are being treated using percutaneous coronary interventions. A number of studies have shown good results in other lesions and in high-risk patients with, for example, bifurcation lesions, chronic occlusions or diabetes. Intracoronary ultrasound is the predominant intracoronary diagnostic technique and it can be used to assist in optimizing DES implantation. In addition, measurement of the fractional flow reserve is helpful in evaluating the severity of moderate lesions whereas the high-resolution images provided by optical coherence tomography are particularly informative. Multislice computed tomography enables the presence of coronary artery disease to be ruled out and the technique is also useful as a complementary tool for interventional cardiologists. Research into regenerative techniques is promising but remains experimental at present. With regard to noncoronary interventions, new data have become available that support the use of a percutaneous approach in patients with patent foramen ovale. In addition, clinical experience with percutaneous aortic valve replacement, via either the transfemoral or transapical route, is increasing.