Kissing Balloon Inflation in Percutaneous Coronary Interventions

Optimal kissing balloon inflation after single-stent deployment in a coronary bifurcation model

AIMS

To define the optimal kissing balloon inflation (KBI) after single-stent deployment in a coronary bifurcation model.

METHODS AND RESULTS

We deployed stents in main vessels (MV) followed by KBI in various conditions and compared the stent configurations. A) KBI at the operator's discretion vs. under the guidelines of minimal balloon overlapping (MBO). Various stent configurations were observed after the former option, whereas similar maximal dilation points were observed under the MBO guidelines. B) Long balloon overlapping (LBO) vs. MBO with proximal MV dilated by a large balloon. The proximal MV was dilated to an ideal round shape with MBO versus an oval shape with LBO. C) Two-link vs. 3-link stents. Although the 2-link stent was advantageous to open the side branch, it incurred a risk of overdilatation of the proximal struts, whereas the 3-link stent preserved its structure. Computed simulations of coronary flow were analysed in the following left main coronary models: circle with a diameter of 4 and 5.5 mm, ellipse with longitudinal direction and tilt position. They revealed that the overdilated side was exposed to low shear stress regardless of its shape.

CONCLUSIONS

Optimal KBI can be achieved with MBO and proximal dilatation by an optimally sized balloon.

Differential Prognostic Effect Between First- and Second-Generation Drug-Eluting Stents in Coronary Bifurcation Lesions: Patient-Level Analysis of the Korean Bifurcation Pooled Cohorts

OBJECTIVES

The purpose of this study was to investigate the differential clinical outcomes after percutaneous coronary intervention (PCI) for coronary bifurcation lesions with 1- or 2-stenting techniques using first- or second-generation drug-eluting stents (DES).

BACKGROUND

The 2-stenting technique has been regarded to have worse clinical outcomes than the 1-stenting technique after bifurcation PCI with first-generation DES. However, there has been a paucity of data comparing the 1- and 2-stenting techniques with the use of second-generation DES.

METHODS

Patient-level pooled analysis was performed with 3,162 patients undergoing PCI using first- or second-generation DES for bifurcation lesions from the "Korean Bifurcation Pooled Cohorts" (COBIS [Coronary Bifurcation Stenting] II, EXCELLENT [Registry to Evaluate Efficacy of Xience/Promus Versus Cypher in Reducing Late Loss After Stenting], and RESOLUTE-Korea [Registry to Evaluate the Efficacy of Zotarolimus-Eluting Stent]). The 3-year clinical outcomes were compared between 1- and 2-stenting techniques, stratified by the type of DES.

RESULTS

With first-generation DES, rates of target lesion failure (TLF) or patient-oriented composite outcome (POCO) (a composite of all death, any myocardial infarction, any repeat revascularization, and cerebrovascular accidents) at 3 years were significantly higher after the 2-stenting than the 1-stenting technique (TLF 8.6% vs. 17.5%; p < 0.001; POCO 18.1% vs. 28.5%, p < 0.001). With second-generation DES, however, there was no difference between 1- and 2-stenting techniques (TLF 5.4% vs. 5.8%; p = 0.768; POCO 11.2% vs. 12.9%; p = 0.995). The differential effects of 2-stenting technique on the prognosis according to the type of DES were also corroborated with similar results by the inverse probability weighted model. The 2-stenting technique was a significant independent predictor of TLF in first-generation DES (hazard ratio: 2.046; 95% confidence interval: 1.114 to 3.759; p < 0.001), but not in second-generation DES (hazard ratio: 0.667; 95% confidence interval: 0.247 to 1.802; p = 0.425).

CONCLUSIONS

Patient-level pooled analysis of 3,162 patients in Korean Bifurcation Pooled Cohorts demonstrated that the 2-stenting technique showed comparable outcomes to 1-stenting technique with second-generation DES, which is different from the results of first-generation DES favoring the 1-stenting technique.

Final kissing balloon inflation: the whole story

Final kissing balloon inflation (KBI) after provisional bifurcation stenting has failed to provide clear clinical benefit except for a decrease in side branch stenosis, while a significant reduction of major adverse cardiac events has been documented in two-stent deployment. The optimisation of KBI in terms of proximal optimisation technique, appropriate guidewire re-crossing, minimal balloon overlapping, and balloon size selection may overcome the drawbacks of conventional KBI by: 1) correcting the proximal malapposition expected from fractal geometry; 2) optimising side branch ostium strut opening while conserving a bifurcation area free of malapposition at both the carina and the side branch ostium; and 3) optimising the geometry, velocity fields and shear rate.

Characteristics of drug-eluting stent platforms potentially influencing bifurcated lesion provisional stenting procedure

AIMS

We aimed to review the technical characteristics of DES platforms which have been documented to influence bifurcation stenting procedures conducted according to the provisional approach.

METHODS AND RESULTS

DES platforms have remarkable technical differences (side cell diameter, shape, deformability, etc.). We reviewed the literature data and performed original virtual bench tests to highlight the characteristics of DES platforms which influence the following phases of bifurcation stenting conducted according to the provisional approach: stent implantation in the main vessel across side-branch take-off ("crossover" stenting), proximal optimisation technique, rewiring and kissing balloon inflation. Available data show that the response of different DES platforms to the various procedural steps of provisional stenting is different.

CONCLUSIONS

When treating bifurcated lesions according to the provisional stenting approach, the search for an ideal matching between individual bifurcated anatomy and DES selection should take into account an articulated series of technical parameters.

IVUS in bifurcation stenting: what have we learned?

Coronary angiography is unable to visualise the atherosclerotic involvement of the arterial wall. Bifurcation lesions are particularly difficult to assess by angiography because overlapping mother and daughter vessels often obscure the lesion and carina. On the contrary, IVUS imaging allows for precise, real-time, cross-sectional assessment of all bifurcation lesion segments, enabling measurements of luminal and vessel areas. Moreover, IVUS evaluation of stent expansion, apposition and edge problems is also superior to angiographic assessment. In spite of the lack of adequately powered randomised trials, there is growing evidence from large registries and meta-analyses showing better acute and long-term outcomes of DES implantation guided by IVUS, in comparison to angiography-guided procedures. In this review, we summarise current scientific evidence, the European Society of Cardiology recommendations and the European Bifurcation Club consensus for the use of IVUS in bifurcation stenting.

To kiss or not to kiss? Impact of final kissing-balloon inflation on early and long-term results of percutaneous coronary intervention for bifurcation lesions

Final kissing-balloon inflation is often recommended for percutaneous coronary intervention (PCI) of bifurcation lesions. However, randomized trials focusing on kissing inflation have not confirmed its beneficial impact. We compared outcomes of kissing inflation for PCI of bifurcation lesions, explicitly stratifying results according to stenting strategy. Patients undergoing bifurcation PCI were retrospectively enrolled. Subjects receiving final kissing inflation were compared with those not undergoing kissing inflation, after stratification for a single-stent technique. The primary end point was the long-term rate of major adverse cardiac events (MACE, i.e., death, myocardial infarction, or target lesion revascularization (TLR)). A total of 4314 patients were included: 1176 (27.3 %) treated with a single stent and kissing inflation, 1637 (37.9 %) with a single stent but no kissing, 1072 (24.8 %) with two stents and kissing, and 429 (9.9 %) with two stents but no kissing. At unadjusted analyses kissing was associated with fewer short-term MACE and deaths in the two-stent group, and with fewer long-term MACE, cardiac deaths, and side-branch TLR in the two-stent group (all P < 0.05). Conversely, kissing appeared detrimental after single stenting. However, after multivariable analyses, kissing no longer significantly affected the risk of adverse events, with the exception of the risk of side-branch TLR, which was lower in those receiving two stents and final kissing inflation (hazard ratio = 0.52, 95 % confidence interval 0.30–0.90, P = 0.020). Kissing inflation can be avoided in bifurcation lesions uneventfully treated with single-stent PCI. However, final kissing-balloon inflation appears beneficial in reducing the risk of side-branch repeat revascularization after using a two-stent strategy.

Assessment of side branch predilation before a provisional T-stent strategy for bifurcation lesions. A randomized trial

BACKGROUND

A simple approach is the predominant strategy for the percutaneous coronary intervention of bifurcation lesions. Performing side branch (SB) predilation in this context is currently a matter of controversy. In this study, we assess the efficacy of SB predilatation before a provisional T-stent strategy for bifurcation lesions.

METHODS

Between February 2009 and November 2012, 372 patients with true bifurcation lesions were randomized to either predilation of the SB (n = 187) or no predilatation (n = 185) before main branch (MB) stent implantation and a subsequent SB provisional stent strategy.

RESULTS

There were no significant differences between the patient groups regarding the baseline characteristics. After MB stent implantation, the TIMI flow of the SB was higher in the patients with SB predilation: TIMI flow 0 to 1; 2 (1%) versus 18 (10%), P < .001; and TIMI flow III; 179 (96%) versus 152 (82%), P < .001. Side branch stenting rates were 4% versus 3%, P = not significant. In addition, 60 patients (32%) from the SB predilation group presented SB residual stenosis by visual inspection <50%, and TIMI flow ≥III did not require any additional treatment. The failure rate of SB rewiring, the time of rewiring, the number of wires used, and the incidence of major events were similar in both groups of patients.

CONCLUSIONS

Predilation of the SB resulted in improved TIMI flow after MB stenting and less indication to subsequently treat the SB. If rewiring of the SB is required, predilation did not hinder this maneuver.

Dedicated two-stent technique in complex bifurcation percutaneous coronary intervention with use of everolimus-eluting stents: the EES-bifurcation study

OBJECTIVES

To compare the outcomes of initial one-stent (1S) versus dedicated two-stent (2S) strategies in complex bifurcation percutaneous coronary intervention (PCI) using everolimus-eluting stents (EES).

BACKGROUND

PCI of true bifurcation lesions is technically challenging and historically associated with reduced procedural success and increased restenosis. Prior studies comparing initial one-stent (1S) versus dedicated two-stent (2S) strategies using first-generation drug-eluting stents have shown no reduction in ischemic events and more complications with a 2S strategy.

METHODS

We performed a retrospective study of 319 consecutive patients undergoing PCI at a single referral center with EES for true bifurcation lesions, defined by involvement of both the main vessel (MV) and side branch (SB). Baseline, procedural characteristics, quantitative coronary angiography and clinical outcomes in-hospital and at one year were compared for patients undergoing 1S (n=175) and 2S (n=144) strategies.

RESULTS

Baseline characteristics were well-matched. 2S strategy was associated with greater SB acute gain (0.65±0.41 mm vs. 1.11±0.47 mm, p<0.0001). In-hospital serious adverse events were similar (9% with 2S vs. 8% with 1S, p=0.58). At one year, patients treated by 2S strategy had non-significantly lower rates of target vessel revascularization (5.8% vs. 7.4%, p=0.31), myocardial infarction (7.8% vs. 12.2%, p=0.31) and major adverse cardiovascular events (16.6% vs. 21.8%, p=0.21).

CONCLUSION

In this study of patients undergoing PCI for true coronary bifurcation lesions using EES, 2S strategy was associated with superior SB angiographic outcomes without excess complications or ischemic events at one year.

Impact of kissing balloon inflation on the main vessel stent volume, area, and symmetry after side-branch dilation in patients with coronary bifurcation lesions: a serial volumetric intravascular ultrasound study

OBJECTIVES

Intravascular ultrasound (IVUS) was performed to investigate the impact of kissing balloon inflation (KBI) on the main vessel (MV) stent volume, area, and symmetry after side-branch (SB) dilation in patients with coronary bifurcation lesions (CBL).

BACKGROUND

It remains controversial whether KBI would restore the MV stent area and symmetry loss after SB dilation.

METHODS

A total of 88 serial IVUS examinations of the MV were performed after MV angioplasty, MV stenting, SB dilation, and KBI in 22 patients with CBL. The MV stent was divided into proximal, bifurcation, and distal segments; the stent volume index (SVI), minimal stent area (MSA), stent symmetry index (SSI), and external elastic membrane (EEM) volume index were measured in 198 stent segments and compared after MV stenting, SB dilation, and KBI.

RESULTS

In the bifurcation segment, SVI, MSA, and SSI were significantly smaller after SB dilation than after MV stenting and KBI (SVI was 6.10 ± 1.50 mm(3)/mm vs. 6.68 ± 1.60 mm(3)/mm and 6.57 ± 1.60 mm(3)/mm, respectively, p < 0.05; MSA was 5.15 ± 1.30 mm(2) vs. 6.08 ± 1.40 mm(2) and 5.86 ± 1.50 mm(2), respectively, p < 0.05; and SSI was 0.78 ± 0.02 mm(2) vs. 0.87 ± 0.03 mm(2) and 0.84 ± 0.03 mm(2), respectively, p < 0.05). KBI restored the MV SVI, MSA, and SSI after SB dilation. In the proximal segment, SVI, MSA, and EEM volume index were significantly larger, but SSI was smaller after KBI than after MV stenting and SB dilation. In the distal segment, neither SB dilation nor KBI had a significant impact on the MV stent volume or symmetry.

CONCLUSIONS

This is the first comprehensive volumetric IVUS analysis of CBL, to our knowledge, demonstrating that KBI restores the MV stent volume, area, and symmetry loss after SB dilation in the bifurcation segment, and induces asymmetric stent expansion in the proximal segment.

Approach to coronary bifurcation lesions using the everolimus-eluting stent: comparison between a simple strategy and a complex strategy with T-stenting

INTRODUCTION AND OBJECTIVES

Coronary bifurcation lesions can be approached using a simple or a complex strategy. In clinical trials with first-generation drug-eluting stents, the complex strategy was not superior to the simple approach. However, to date, the best strategy when using second-generation drug-eluting stents has not been defined.

METHODS

We performed a prospective randomized study comparing a simple vs a complex strategy involving T-stenting for the percutaneous revascularization of bifurcation lesions using the everolimus-eluting stent. Angiographic and clinical follow-up were performed at 9 months.

RESULTS

We included 70 lesions in 69 patients, who were randomized to the simple (34 lesions, 33 patients) or complex strategy (36 lesions and patients). In all, 85.6% of the lesions included were true bifurcations. The crossover rate was 17.1%. The binary restenosis rate was 12.1%, with no differences between the groups. Side branch restenosis tended to be higher with the simple strategy in the intention to treat analysis (10.7% vs 0%) but not in the per protocol analysis (5.9% vs 4.2%). The incidence of major adverse cardiac events (cardiac death, myocardial infarction, and target vessel revascularization) was 9.2%, with no differences between groups. There were no cases of stent thrombosis.

CONCLUSIONS

According to the clinical and angiographic findings, the complex strategy was not significantly superior to the simple approach in the revascularization of bifurcation lesions with second-generation everolimus-drug eluting stents.

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.