Impact of branching angle on neointimal coverage of drug-eluting stents implanted in bifurcation lesions

Impact of coronary bifurcation angle on stent malapposition in a randomized comparison between proximal optimization technique followed by side branch dilatation and kissing balloon inflation

Background

The impact of coronary bifurcation angle (BA) on incomplete stent apposition (ISA) after crossover stenting followed by side branch (SB) intervention has not been established.

Methods

A total of 100 crossover stentings randomly treated with proximal optimization technique followed by short balloon dilation in the SB (POT-SBD group, 48 patients) and final kissing balloon technique (KBT group, 52 patients) were analyzed in the PROPOT trial. Major ISA with maximum distance > 400 μm and its location was determined using optical coherence tomography before SB intervention and at the final procedure. The BA was defined as the angle between the distal main vessel and SB. Optimal POT was determined when the difference in stent volume index between the proximal and distal bifurcation was greater than the median value (0.86 mm3/mm) before SB intervention.

Result

Major ISA was more frequently observed in the POT-SBD than in the KBT group (35% versus 17%, p < 0.05). In the POT-SBD group, worsening ISA after SBD was prominent at the distal bifurcation. The BA was an independent predictor of major ISA (odds ratio 1.04, 95% confidence interval 1.00-1.07, p < 0.05) with a cut-off value of 59.5° (p < 0.05). However, the cases treated with optimal POT in the short BA (<60°) indicated the lowest incidence of major ISA. In the KBT group, BA had no significant impact.

Conclusion

A wide BA has a potential risk for the occurrence of major ISA after POT followed by SBD in coronary bifurcation stenting.

Impact of coronary bifurcation angle on the pathogenesis of atherosclerosis and clinical outcome of coronary bifurcation intervention–A scoping review

Background

A coronary bifurcation stenting is still a challenging issue due to frequent restenosis and stent thrombosis even with drug-eluting stents. The bifurcation angle (BA) between a main vessel and a side branch is one of the crucial determinants of coronary flow and shear stress that affect the plaque distribution. Previous bench and clinical studies have evaluated the impact of the BA between the proximal main vessel and the side branch (Angle A) and the BA between the distal main vessel and the side branch (Angle B) on the clinical outcomes of bifurcation stenting. However, the impact has not yet been fully elucidated due to a lack of statistical power or different manner of the assessment of BA.

Objectives

To analyze the published studies on coronary artery BA, the modalities used for assessment, and the impact of BA on interventions and attempt to define the pre-procedural protocols.

Data sources

A scoping review was performed using the Joanna Briggs Institute Methodology. A total of 52 relevant references were selected from PubMed, Cochrane Library, and CINAHL databases and categorized into three topic areas.

Results and conclusions

A wider Angle A is associated with the increased likelihood of carina shift and a wider Angle B, with that of side branch occlusion. A wider Angle B promotes stent malapposition and deformation in the side branch ostium and has been reported as an independent predictor of major adverse cardiac events after bifurcation stenting; however, improvement of the drug-eluting stent, refinement of the stenting technique, and accurate 3-dimensional assessment may attenuate the adverse clinical impact of a wider BA.

Implications of key findings

Assessment of the BA is necessary to predict the effect of bifurcation intervention procedure on the stent configuration and coronary flow at the bifurcated vessels. This will help to optimize stent selection and the stenting technique.

Vascular healing after kissing balloon inflation: Nine-month 3D optical coherence tomography analysis in corelab

Background

The jailing strut configuration with link-free and distal guidewire recrossing (LFD) at the side branch orifice (SBO) reduces incomplete stent apposition (ISA) after kissing balloon technique (KBT) in crossover stenting of coronary bifurcation lesions (CBLs). However, data regarding vascular healing after KBT are lacking. We investigated vascular healing 9 months after crossover stenting followed by KBT with optical coherence tomography (OCT) guidance in a prospective multicenter registry.

Methods

Fifty-nine patients with CBLs (LFD, 35 patients; non-LFD, 24 patients) were studied. The jailing configuration of the SB and the wire-recrossing position, incidence of ISA and uncovered struts, and neointima unevenness score (NUS) in the main vessel (MV) after 9 months were determined by off-line 3D-OCT in the core laboratory.

Results

The ISA rate was significantly higher at the SB ostium and distal MV after KBT in the non-LFD group, compared to the LFD group. After 9 months, incidence of ISA (18.3 ± 18.2 vs. 6.0 ± 8.7%, p < 0.01) and uncovered struts (8.7 ± 9.9 vs. 4.7 ± 7.3 %, p = 0.08) were higher at the SB ostium with higher SB restenosis in the non-LFD group. In distal MV, NUS was significantly higher (3.1 ± 1.1 vs. 2.5 ± 0.6, p < 0.05). In true-CBLs, an increase in uncovered struts and ISA rate was prominent in the proximal MV and opposite SB. No differences were observed in the 9-month clinical outcomes.

Conclusion

Visualization of the wire recrossing point and the SB-jailing strut pattern by OCT plays an important role to optimize the KBT in CBL stenting, resulting in favorable mid-term vascular healing.

Feasibility, reproducibility and characteristics of coronary bifurcation type assessment by three-dimensional optical coherence tomography

Aim

To investigate the characteristics of coronary artery bifurcation type (parallel or perpendicular type) using three-dimensional (3D) optical coherence tomography (OCT), and determine the feasibility, reproducibility, assessment time and correlation with bifurcation angles measured by 3D quantitative coronary angiography (QCA).

Methods and results

We evaluated 60 lesions at the coronary bifurcation that were treated by main vessel (MV) stenting with kissing balloon inflation (KBI) under OCT/optical frequency domain imaging (OFDI) guidance. Inter- and intra-observer agreement regarding the assessment of 3D bifurcation types were 0.88 and 0.94, respectively. The assessment times of 3D-OCT bifurcation type with OCT and OFDI were within about 30 seconds. 3D-OCT bifurcation types showed the greatest correlation with the distal bifurcation angle assessed by 3D-QCA among the three bifurcation angles (distal bifurcation angle, proximal bifurcation angle and main vessel angle), and the optimal cut-off distal bifurcation angle to predict a perpendicular type bifurcation, as determined by ROC analysis, was 51.0° (AUC 0.773, sensitivity 0.80, specificity 0.67). Based on this cut-off value for the distal bifurcation angle (51°), the diagnostic accuracy for perpendicular type bifurcation in cases with a BA ≥ 51° (n = 34) was 70.6% (24/34) and that of the parallel type bifurcation in cases of BA < 51° (n = 26) was 76.9% (20/26).

Conclusion

Performing 3D-OCT for assessment of coronary artery bifurcation type is feasible and simple, and can be done in a short time with high reproducibility.

Relationship between neointimal strut bridge and jailed side-branch ostial area

BACKGROUND

Our study analyzed the relationship between the neointimal strut bridge and jailed side-branch (SB) ostial area in patients with coronary heart disease (CHD) who had a single drug-eluting stent (DES) crossover of the left anterior descending coronary artery (LAD)/diagonal branch (D) bifurcation.

PATIENTS AND METHODS

A total of 64 CHD patients with an LAD/D bifurcation treated by optical coherence tomography (OCT)-guided single-DES implantation and followed up at 1 year after primary percutaneous intervention (pPCI) were enrolled in our study. According to the two-dimensional OCT results, patients were divided into a non-neointimal bridge group (n = 44) and a neointimal bridge group (n = 20). Basic clinical, angiographic, 2D and 3D OCT, and DES results were analyzed.

RESULTS

The blood lipid levels of the two groups after the 1‑year follow-up were lower than the levels 1 year earlier (p < 0.05). There was a notable decrease in the SB ostial minimum lumen diameter and area directly after pPCI vs. before pPCI in both groups. The diameter stenosis directly after pPCI showed a clear increase compared with the pre-pPCI value in both groups (p < 0.05 or p < 0.01, respectively). The strut distance of the neointimal bridges in the neointimal bridge group was greater than in the non-neointimal bridge group (p < 0.05). A clearly short strut distance of the neointimal bridge was observed compared with the strut distance of the non-neointimal bridge in the neointimal bridge group (p < 0.05). A larger neointimal bridge area and a smaller SB ostial area were found in the neointimal bridge group compared with the non-neointimal bridge group (p < 0.05 or p < 0.01, respectively).

CONCLUSION

A short strut distance facilitated formation of a neointimal bridge, which significantly influenced the SB ostial area after single crossover stenting of the SB orifice at the 1‑year follow-up.

Usefulness of longitudinal reconstructed optical coherence tomography images for predicting the need for the reverse wire technique during coronary bifurcation interventions

OBJECTIVES

The aim is to investigate the usefulness of longitudinal reconstructed optical coherence tomography (OCT) images in selecting the reverse wire (RW) technique for inserting a guidewire into a side branch (SB).

BACKGROUND

It is sometimes necessary to protect the SB with a guidewire to prevent SB complications in PCI for bifurcation lesions. The RW is a novel method for guidewire insertion into an extremely angulated SB when the standard antegrade wire (AW) approach is difficult.

METHODS

This retrospective study included 46 consecutive patients who underwent OCT-guided PCI in bifurcation lesions with significant SB stenosis. Patients were divided into two groups: 36 patients with successful guidewire crossing using the AW (AW group) and 10 patients with unsuccessful AW but successful RW guidewire crossing (RW group). SB angle and branch point (BP) slope, defined as the angle between the line connecting the proximal and distal BPs and the vertical, were measured using longitudinal reconstructed OCT images.

RESULTS

The RW group had a significantly larger SB angle and higher BP slope than the AW group (108.7 ± 11.4° vs. 76.2 ± 14.9°; P < 0.0001, 128.7 ± 31.6° vs. 82.9 ± 33.6°; P = 0.0004, respectively). Receiver operating characteristic curve analysis indicated that SB angle ≥ 100° and BP slope ≥ 120° are optimal cutoff values for predicting the need for RW (area under the curve 0.97, sensitivity 90.0%, specificity 91.7%; area under the curve 0.83, sensitivity 80.0%, specificity 86.1%, respectively).

CONCLUSIONS

Longitudinal reconstructed OCT is useful for selecting the wiring technique for bifurcation lesions.

Serial 3-Dimensional Optical Coherence Tomography Assessment of Jailed Side-Branch by Second-Generation Drug-Eluting Absorbable Metal Scaffold (from the BIOSOLVE-II Trial)

Second-generation drug-eluting absorbable metal scaffold (DREAMS 2G) is used for treating coronary lesions. However, the natural history of the jailed side-branch (SB) after DREAMS 2G implantation remains to be elucidated. The aim of this study is to investigate the effect of scaffold struts on jailed SBs as assessed by 3-dimensional (3D) optical coherence tomography (OCT) after implantation of DREAMS 2G. We enrolled the patients who received a DREAMS 2G implantation and where OCT was performed at postprocedure and 12-month follow-up in the BIOSOLVE-II trial. The area of the ostium of jailed SBs and number of compartments divided by scaffold struts were assessed by cut-plane analysis using 3D OCT. A total of 24 patients with 61 jailed SBs were analyzed in this study. The number of compartments was significantly decreased (postprocedure; 1.98 ± 0.84 vs 12 months; 1.10 ± 0.30, p <0.001) during the 12 months. Since most of the struts disappeared, the ostium area was increased in 62% of jailed SBs at 12 months, however, not significantly different from postprocedure (postprocedure; 0.74 [0.34 to 1.46] mm² vs 12 months; 0.78 [0.41 to 1.68] mm², p = 0.055). The number of compartments created by scaffold struts and branching angle at postprocedure had no effect on the changes of SB ostium area. DREAMS 2G has a favorable absorption process in the jailed SBs up to 12 months and may be considered as an optional therapy for treating lesions that involve SBs.