Bifurcation Coronary Lesions Treated With the “Crush” Technique

Optimal Minimal Stent Area and Impact of Stent Underexpansion in Left Main Up-Front 2-Stent Strategy

BACKGROUND

We previously reported the use of minimal stent area to predict angiographic in-stent restenosis after drug-eluting stent implantation for unprotected left main (LM) disease. We aimed to evaluate the optimal minimal stent area criteria for up-front LM 2-stenting based on long-term clinical outcomes.

METHODS

We identified 292 consecutive patients with LM bifurcation stenosis who were treated using the crush technique. The final minimal stent area was measured in the ostial left anterior descending artery (LAD), ostial left circumflex artery (LCX), and distal LM. The primary outcome was 5-year major adverse cardiac events, including all-cause death, myocardial infarction, and target lesion revascularization.

RESULTS

The minimal stent area cutoff values that best predicted the 5-year major adverse cardiac events were 11.8 mm2 for distal LM (area under the curve, 0.57; P=0.15), 8.3 mm2 for LAD ostium (area under the curve, 0.62; P=0.02), and 5.7 mm2 for LCX ostium (area under the curve, 0.64; P=0.01). Using these criteria, the risk of 5-year major adverse cardiac events was significantly associated with stent underexpansion in the LAD ostium (hazard ratio, 3.14; [95% CI, 1.23-8.06]; P=0.02) and LCX ostium (hazard ratio, 2.60 [95% CI, 1.11-6.07]; P=0.03) but not in the distal LM (hazard ratio, 0.81 [95% CI, 0.34-1.91]; P=0.63). Patients with stent underexpansion in both ostial LAD and LCX had a significantly higher rate of 5-year major adverse cardiac events than those with no or 1 underexpanded stent of either ostium (P<0.01).

CONCLUSIONS

Stent underexpansion in the LAD and LCX ostium was significantly associated with long-term outcomes in patients who underwent up-front 2-stenting for LM bifurcation stenosis.

Clinical Outcomes Following Simple or Complex Stenting for Coronary Bifurcation Lesions: A Meta-Analysis

Background

Stent placement remains a challenge for coronary bifurcation lesions. While both simple and complex stenting strategies are available, it is unclear which one results in better clinical outcomes. This meta-analysis aims to explore the long-term prognosis following treatment with the 2 stenting strategies.

Method

Randomized controlled trials found from searches of the PubMed, EMBASE, and Cochrane Central Register of Controlled Trials were included in this meta-analysis. The complex stent placement strategy was identified as the control group, and the simple stent placement strategy was identified as the experimental group. Data were synthesized with a random effects model. The quality of the randomized controlled trials was assessed by Jadad scale scores. The clinical endpoints at 6 months, 1 year, and 5 years were analyzed.

Results

A total of 11 randomized controlled trials met the inclusion criteria. A total of 2494 patients were included in this meta-analysis. The odds ratio [OR] of the major adverse cardiac events (MACEs) at 6 months was 0.85 (95% confidence interval [CI] 0.53-1.35; P = .49, I ² = 0%). The OR of the MACEs at 1 year was 0.61 (95% CI 0.36-1.05; P = .08, I ² = 0%). The OR of the MACEs at 5 years was 0.69 (95% CI 0.51-0.92; P = .01, I ² = 0%). Compared with the complex strategy, the simple strategy was associated with a lower incidence of MACEs at 5 years.

Conclusion

Compared to the complex stenting strategy, the simple stenting strategy can better reduce the occurrence of long-term MACEs for coronary bifurcation lesions.

Impact of intravascular ultrasound and final kissing balloon dilatation on long-term clinical outcome in percutaneous revascularization with 1-stent strategy for left main coronary artery stenosis in drug-eluting stent era

BACKGROUND

It remains uncertain whether intravascular ultrasound (IVUS) use and final kissing balloon (FKB) dilatation would be standard care of percutaneous coronary intervention (PCI) with a simple 1-stent technique in unprotected left main coronary artery (LMCA) stenosis. This study sought to investigate the impact of IVUS use and FKB dilatation on long-term major adverse cardiac events (MACEs) in PCI with a simple 1-stent technique for unprotected LMCA stenosis.

METHODS

Between June 2006 and December 2012, 255 patients who underwent PCI with 1 drug-eluting stent for LMCA stenosis were analyzed. Mean follow-up duration was 1663 ± 946 days. Long-term MACEs were defined as death, nonfatal myocardial infarction (MI) and repeat revascularizations.

RESULTS

During the follow-up, 72 (28.2%) MACEs occurred including 38 (14.9%) deaths, 21 (8.2%) nonfatal MIs and 13 (5.1%) revascularizations. The IVUS examination and FKB dilatation were done in 158 (62.0%) and 119 (46.7%), respectively. IVUS use (20.3 versus 41.2%; log-rank P < 0.001), not FKB dilatation (30.3 versus 26.5%; log-rank P = 0.614), significantly reduced MACEs. In multivariate analysis, IVUS use was a negative predictor of MACEs [hazards ratio 0.51; 95% confidence interval (CI) 0.29-0.88; P = 0.017], whereas FKB dilatation (hazard ratio 1.68; 95% CI, 1.01-2.80; P = 0.047) was a positive predictor of MACEs. In bifurcation LMCA stenosis, IVUS use (18.7 versus 48.0%; log-rank P < 0.001) significantly reduced MACEs. In nonbifurcation LMCA stenosis, FKB dilatation showed a trend of increased MACEs (P = 0.076).

CONCLUSION

IVUS examination is helpful in reducing clinical events in PCI for LMCA bifurcation lesions, whereas mandatory FKB dilatation after the 1-stent technique might be harmful in nonbifurcation LMCA stenosis.

Stent Size Optimization in the Femoral Bifurcation Using a Fractal Model: A Morphological Analysis

OBJECTIVES

Stenting of common femoral artery (CFA) bifurcation lesions is complex due to harmonious asymmetric geometry between the CFA and deep or superficial femoral artery. In order to ensure an optimal flow, the stents must be implanted according to the diameter of the CFA and the diameter of the daughter vessels. The aim of this study was to validate a mathematical formula for the CFA bifurcation in order to optimize the implantation of stents in this bifurcation with a fast and efficient method.

MATERIALS/METHODS

We retrospectively included all patients who underwent transcatheter aortic valve implantation and who had a healthy CFA bifurcation on the CT-scan. Diameters of the mother vessel (D_m), daughter vessels (D_l: larger vessel; D_s: smaller vessel), and the ratio between the two were calculated. According to the latter, the following linear model was proposed: [D_m = (D_m/D_l + D_s) × (D_l + D_s)] and was compared to the four existing models (Murray, HK, Flow, Finet). Finally, we calculated the relative error between the prediction of the four models and the measurements.

RESULTS

Overall, 110 CFA bifurcations were included. Mean CFA diameter was 7.75 ± 1.67 mm. Mean D_l diameter was 5.79 ± 1.21 mm and mean D_s diameter was 5.23 ± 1.09 mm. A reduction of 25 % was seen between the CFA and the larger daughter-vessel. The mean ratio between the CFA and the daughter vessels was 0.71. Our model [D_m = 0.71× (D_l + D_s)] and the flow law were the most accurate (relative difference of 1.59 ± 11.97% and 1.01 ± 11.94%, respectively). However, Murray's law had a statistically significant deviation from the real mother-vessel diameter (P < 0.001).

CONCLUSIONS

We developed a simple fractal ratio between CFA and daughter vessels, which could be easily used in daily practice during CFA percutaneous reconstruction to identify the optimal diameters of the diseased vessels.

Histopathologic and physiologic effect of bifurcation stenting: current status and future prospects

Introduction: Coronary bifurcation lesions are involved in up to 20% of all percutaneous coronary interventions (PCI). However, bifurcation lesion intervention is associated with a high complication rate, and optimal treatment of coronary bifurcation is an ongoing debate.Areas covered: Both different stenting techniques and a variety of devices have been suggested for bifurcation treatment, including the use of conventional coronary stents, bioresorbable vascular scaffolds (BVS), drug-eluting balloons (DEB), and stents dedicated to bifurcations. This review will summarize different therapeutic approaches with their advantages and shortcomings, with special emphasis on histopathologic and physiologic effects of each treatment strategy.Expert opinion: Histopathology and clinical data have shown that a more simple treatment strategy is beneficial in bifurcation lesions, achieving superior results. Bifurcation interventions through balloon angioplasty or placement of stents can importantly alter the bifurcation's geometry and accordingly modify local flow conditions. Computational fluid dynamics (CFD) studies have shown that the outcome of bifurcation interventions is governed by local hemodynamic shear conditions. Minimizing detrimental flow conditions as much as possible should be the ultimate strategy to achieve long-term success of bifurcation interventions.

Randomized comparison between 2-link cell design biolimus A9-eluting stent and 3-link cell design everolimus-eluting stent in patients with de novo true coronary bifurcation lesions: the BEGIN trial

The appropriate stent platform for treating coronary bifurcation lesions (CBLs) remains controversial. Previous bench tests have demonstrated the superiority of a 2-link cell design to 3-link cell design for creating inter-strut dilation at the side branch ostium. This randomized multicenter prospective BEGIN trial compared the biodegradable polymer-based biolimus A9-eluting stent (2-link BES) with the durable polymer-based cobalt chromium everolimus-eluting stent (3-link EES) in 226 patients with de novo CBLs. Patients with true bifurcations, defined as > 50% stenosis in the main vessel and side branch (SB) and an SB diameter > 2.25 mm, were enrolled. Guide wire re-crossing to the distal cell (near the carina) in the jailed SB and final kissing inflation were recommended. The SB angiographic endpoint was < 50% stenosis diameter. Left-main CBLs (13.5% vs. 13.0%) and 2-stent technique (30.6% vs. 22.6%) rates were similar. The primary endpoints (minimum lumen diameter at the SB ostium measured at an independent core laboratory at the 8-month follow-up) were comparable (1.64 ± 0.50 mm vs. 1.63 ± 0.51 mm, p = 0.976). There was no significant difference in composite outcomes of cardiac death, myocardial infarction, or target vascular revascularization at 12 months (7.4% vs. 8.0%, p = 0.894). Two-link BES and 3-link EES showed similar 8-month angiographic and 1-year clinical outcomes for true CBLs.

A novel technique for coronary bifurcation intervention: Double rewire crush technique and its clinical outcomes after 2 years of follow-up

OBJECTIVES

To describe procedural details of the double rewire (DR) crush technique, a novel modified crush technique, and report the clinical outcomes of patients who underwent the procedure.

BACKGROUND

In the management of complex bifurcation lesions, there is a need to use elective two-stent techniques that stent the side branch (SB) before main vessel (MV) stenting and keep SB open.

METHODS

We studied 48 patients with 49 bifurcation lesions who underwent percutaneous coronary intervention (PCI) using the DR-crush technique between January and December 2013. Baseline, postprocedural, and follow-up quantitative coronary angiographic analyses were performed. Procedural characteristics and clinical outcomes at follow-up were assessed.

RESULTS

Majority of the patients (60.4%, 29/48) had acute coronary syndrome. Most bifurcation lesions (77.6%, 38/49) were classified as Medina 1, 1, 1. Final kissing balloon inflation was successfully performed in all patients. After PCI, MV and SB of all patients had Thrombolysis In Myocardial Infarction 3 blood flow. None of the patients had MV or SB diameter stenosis ≥50% after PCI. At a mean follow-up period of 2.4 years, target vessel revascularization occurred in 2.1% and myocardial infarction in 2.1%. No deaths occurred in this period.

CONCLUSIONS

The DR-crush technique is feasible in coronary bifurcation stenting. Patients who underwent this procedure had relatively low incidence of adverse events. Larger studies are warranted for further confirmation of the findings.

Modified double-stent strategy may be an optimal choice for coronary bifurcation lesions: A systematic review and meta-analysis

BACKGROUND AND OBJECTIVE

The modified double-stent and provisional stenting strategies have been widely used in patients with coronary bifurcation lesions, but what is the optimization has not been clearly defined. This meta-analysis is to elucidate the benefits from modified double-stent and provisional stenting strategies in patients with coronary bifurcation lesions.

METHODS

Electronic databases were searched to identify studies comparing the modified double-stent and provisional stenting strategies in patients with coronary bifurcation lesions. The clinical outcomes were divided into early (≤6 months) and late (>6 months) events according to the follow-up duration. The early endpoints included cardiac death, myocardial infarction, target lesion revascularization or target vessel revascularization, and major adverse cardiac events (MACE), and the late endpoints also include stent thrombosis in addition to the early endpoints index. The angiographic endpoint was in-stent restenosis. Data were analyzed by the statistical software RevMan (version 5.3).

RESULTS

A total of 6 studies involving 1683 patients with coronary bifurcation lesions were included in this meta-analysis, which found that the modified double-stent strategy was associated with a lower risk of cardiac death (odds ratio [OR] = 0.29, 95% confidence intervals [CI] 0.11-0.78, P = .01), myocardial infarction (OR = 0.41, 95% CI 0.21-0.82, P = .01), target lesion revascularization or target vessel revascularization (OR = 0.31, 95% CI 0.15-0.63, P = .001), and MACE (OR = 0.41, 95% CI 0.22-0.74, P = .003) compared with provisional stenting in the early follow-up endpoint events, while the risk of cardiac death and stent thrombosis were similar between both strategies (OR = 0.59, 95% CI 0.31-1.10, P = .09; and OR = 0.62, 95% CI 0.34-1.15, P = .13; respectively) in the late follow-up endpoint events. There were significant differences between both strategies in myocardial infarction (OR = 0.42, 95% CI 0.24-0.75, P = .003), MACE (OR = 0.44, 95% CI 0.31-0.62, P < .00001), and target lesion revascularization or target vessel revascularization (OR 0.35, 95% CI 0.25-0.49, P < .00001) between both strategies in the late follow-up endpoint events. The risk of in-stent restenosis favored the modified double-stent strategy (OR 0.29, 95% CI 0.20-0.43, P < .00001).

CONCLUSION

The modified double-stent strategy is associated with excellent clinical and angiographic outcomes except for the occurrence of cardiac death and stent thrombosis late-term outcome compared with provisional stenting strategy in patients with coronary bifurcation lesions. These findings suggest that the modified double-stent strategy can be recommended as an optimization in patients with coronary bifurcation lesions.

The modified balloon crush technique: A simplified approach to optimizing final kissing balloon inflation

This study aimed to investigate the feasibility and safety of the modified balloon crush technique.The conventional crush technique accompanies difficult and suboptimal final kissing balloon inflation (FKI)In a single-center percutaneous coronary intervention registry, 515 patients with 515 bifurcation lesions were treated with the modified balloon technique (n = 70) or the conventional crush technique (n = 445). In contrast to the conventional crush technique, where the implanted side branch (SB) stent is crushed by expansion of the main branch (MB) stent, the modified balloon crush technique uses balloon crushing and additional SB ballooning across the crushed SB stent before MB stenting to facilitate FKI. The primary outcome of interest was major adverse cardiovascular event (MACE), a composite of all-cause death, spontaneous myocardial infarction, and target vessel revascularization.Baseline clinical and angiographic characteristics were similar between the 2 treatment groups. FKI had comparable success rates in both groups (97.1% for the modified balloon group and 98.4% for the conventional crush group; P = .35). There were no differences in procedure time, fluoroscopic time, or contrast amount between the 2 groups. At 1-year follow up, the cumulative MACE incidences were comparable between the 2 groups (7.3% vs 8.8%; P = .73). The incidence of target lesion revascularization (TLR) was significantly lower after the modified balloon crush technique compared with the conventional crush technique (0% vs 5.6%; P = .048).The modified balloon crush technique appears to be a feasible and safe alternative to the conventional crush technique with the potential to reduce the revascularization rate.

Three-Year Major Clinical Outcomes of Angiography-Guided Single Stenting Technique in Non-Complex Left Main Coronary Artery Diseases

There is limited long-term comparative clinical outcome data concerning angiography- versus intravascular ultrasound (IVUS)-guided percutaneous coronary intervention (PCI) in non-complex left main coronary artery (LMCA) disease treated with the single stenting technique in the drug-eluting stent (DES) era.The aim of this study was to investigate whether angiography-guided stenting is comparable to IVUS-guided stenting during 3-year clinical follow-up periods in patients with non-complex LM disease treated with the single stenting technique.A total of 196 patients treated with either angiography-guided (n = 74) or IVUS-guided (n = 122) PCI were included. The primary outcome was the occurrence of major adverse cardiac events (MACE) defined as total death, non-fatal myocardial infarction (MI), target lesion revascularization (TLR), target vessel revascularization (TVR), and non-target vessel revascularization (Non-TVR). To adjust for any potential confounders, propensity score (PS) adjusted analysis was performed.During 3-year follow-up, the PS adjusted Cox-proportional hazard ratio (HR) was not significantly different between the two groups for total death, cardiac death, and MI. Also, TLR and the combined rates of TVR and non-TVR were not significantly different. Finally, MACE was not significantly different between the two groups (HR: 0.63, 95% Confidence interval (CI): 0.33-1.17; P = 0.149).Angiography-guided PCI for non-complex LMCA diseases treated with the single stenting technique showed comparable results compared with IVUS-guided PCI in reducing clinical events during 3-year clinical follow-up in the DES era. Although IVUS guided PCI is the ideal strategy, angiography-guided PCI can be an option for LMCA PCI in some selected cases.

Angiographic study of the clinical liaison of drug-eluting stent and paclitaxel-eluting balloon in unifocal side branch ostium stenosis (ASCLEPIUS)

A reliable stenting strategy for treating isolated side branch (SB) ostium stenosis is not well established. The purpose of this study was to examine the 6-month angiographic outcome of a novel technique, called the shoulder technique, on this lesion subtype. Symptomatic patients with isolated SB ostium stenosis, defined as ≥75% diameter stenosis at SB ostium and <50% diameter stenosis in main vessel (MV), were treated with paclitaxel-eluting balloon in MV and drug-eluting stent in SB using the shoulder technique. Angiographic restudy was performed at 5-9 months and clinical follow-up was scheduled regularly every 3 months. There were 46 patients of age 66 ± 12 years with male predominance (76%) recruited. Diagonal ostium (67%) was the most frequent target lesion site. The size and length of paclitaxel-eluting balloon and drug-eluting stent used in MV and SB were 3.01 ± 0.25 and 20 ± 4 mm, and 2.39 ± 0.25 and 17 ± 6 mm, respectively. Angiographic restudy was performed on 43 (93.5%) patients at 6.5 ± 1.6 months. The late loss in MV and SB were 0.04 ± 0.19 and 0.19 ± 0.32 mm, respectively. Angiographic restensosis was seen in 2 (4.7%) patients at SB, whereas no stenosis was induced in MV. Improvement of symptom was reported in 36 (78%) patients. At 1-year follow-up, no death, myocardial infarction, and stent thrombosis was observed; target vessel revascularization was performed on 3 (6.5%) patients. Treatment of isolated SB ostium stenosis using the shoulder technique is associated with a favorable short-term angiographic outcome.

Impact of very high pressure stent deployment on angiographic and long-term clinical outcomes in true coronary bifurcation lesions treated by the mini-crush stent technique: A single center experience

Background

Percutaneous coronary intervention (PCI) for bifurcation lesions (BL) using 2 stents technique is known to be associated with high rates of procedural failure especially on the side branch (SB) mainly due to stent incomplete apposition. Stent deployment at very high pressure (SDHP) may lead to better stent expansion and apposition. However, SDHP may also be at the origin of deeper wall injury resulting into major cardiac adverse events. No data are available on evaluation of SDHP in BL treated by a mini-crush stent technique.

Methods

One hundred and thirteen consecutive patients underwent PCI for BL (Medina 1, 1, 1) using a mini-crush stent technique with SDHP defined as ≥20 atm. An angiographic follow-up was performed at 6 month and clinical follow-up was obtained at a median of 3 years.

Results

Stent deployment mean pressures were 20 ± 1.4 atm (range 20–25) in the main vessel (MV) and 20 ± 1.5 atm (range 20–25) in SB. Simultaneous final kissing balloon was used in 92% of cases. PCI was successful in 100%. Angiographic follow-up was obtained in 83% of patients. Restenosis rate was 13% (12% restenosis in the SB) with only one case (0.8%) of SB probable thrombosis. Another case of late stent thrombosis occurred at a 3 years clinical follow-up.

Conclusion

Compared with previously published studies in which stents were deployed at lower pressure, SDHP does not increase the restenosis rate in BL using mini-crush stent technique but seems to reduce the rate of stent thrombosis.

Expert Opinion: Optimising Stent Deployment in Contemporary Practice: The Role of Intracoronary Imaging and Non-compliant Balloons

Final stent dimensions remain an important predictor of restenosis, target vessel revascularisation (TVR) and subacute stent thrombosis (ST), even in the drug-eluting stent (DES) era. Stent balloons are usually semi-compliant and thus even high-pressure inflation may not achieve uniform or optimal stent expansion. Post-dilatation with non-compliant (NC) balloons after stent deployment has been shown to enhance stent expansion and could reduce TVR and ST. Based on supporting evidence and in the absence of large prospective randomised outcome-based trials, post-dilatation with an NC balloon to achieve optimal stent expansion and maximal luminal area is a logical technical recommendation, particularly in complex lesion subsets.

Comparative Case-Control analysis of a dedicated self-expanding Biolimus A9-eluting Bifurcation stent versus provisional or mandatory side branch intervention strategies in the treatment of coronary bifurcation lesions

BACKGROUND

In a number of coronary bifurcation lesions, both the main vessel and the side branch (SB) need stent coverage.

OBJECTIVES

To analyze the procedural performance and the impact on radiation times (RT) and contrast medium consumption (CMC) of the Axxess™ stent system (Biosensors, Switzerland) treating de novo bifurcation lesions (DBL).

METHODS

One hundred and ten consecutive prospectively enrolled cases (Axxess Group) and 110 age, sex, and lesion location matched controls undergoing mandatory (Group A, n = 56) or provisional (Group B, n = 54) SB intervention were analyzed.

RESULTS

Although more pre-dilatation was performed in the Axxess Group (92.7% vs. 46.4% [Group A] vs. 24.1% [Group B]), and more stents were used (2.4 vs. 1.2 vs. 1.05), RT and CMC were significantly lower in the Axxess Group [7.9 min/129 ml vs. 14.2 min/209 ml vs. 7.8 min/152 ml; P < 0.001]. Final Thrombolysis In Myocardial Infarction three flow in both branches was significantly more frequent in the Axxess Group (98.2% vs. 94.6% vs. 88.9%; P = 0.02), and post-interventional troponin T elevations were the lowest in the Axxess Group. Eighty one percent of the Axxess-stents could be implanted without technical difficulties. Difficult implantations procedures were mainly related to coronary anatomy. There was no safety concerns (cardiac death, stent-thrombosis) compared to controls. Cumulative 6-months MACE rates were 11% versus 23% versus 25%. TLR rates at 6-months were 5%, 18%, and 15%, respectively.

CONCLUSIONS

Axxess bifurcation stent system procedures were associated with significantly less RT and CMC compared to conventional DBL therapy strategies. Difficult coronary anatomy may hinder successful implantation and a learning curve has to be considered. © 2016 Wiley Periodicals, Inc.

Mechanism of Residual Lumen Stenosis at the Side Branch Ostium After Final Kissing Balloon Inflation: A Volumetric Intracoronary Ultrasound Study of Coronary Bifurcation Lesions

OBJECTIVES

To investigate the mechanisms of residual stenosis (RS) at side branch ostium (SBO) after final kissing balloon inflation (FKI) and clarify the impact of carina- and plaque-shifts on RS.

BACKGROUND

Carina- and plaque-shift induce SBO compromise. FKI is an effective technique to treat this complication; however, RS often persist, and are associated with restenosis at SBO.

METHODS

We performed serial volumetric analysis of 91 bifurcations in which crossover-stenting with FKI and pre-/post-intravascular ultrasounds (IVUS) were completed in both branches. The plaque- and carina-shifts were defined as an increase in the plaque-volume and a decrease in the vessel-volume at the SBO, respectively. RS at the SBO, defined as area stenosis >50% on IVUS, was identified in 19 lesions.

RESULTS

After FKI, the plaque volume- significantly increased at the SBO, with its reduction in the proximal main vessel (MV). However, at the SBO, the volumetric lumen change correlated with vessel change (ρ = 0.690, P < 0.001), but not plaque change (P = 0.390), suggesting that RS at SBO was more likely associated with inadequate vessel stretch, not plaque increase after FKI. Carina-shift was more frequently found in cases with RS, compared to those without RS (37% vs. 11%, P = 0.013). Pre-procedure IVUS findings to predict RS at SBO after FKI were negative-remodeling at distal MV, plaque -burden at distal MV, and plaque-burden at the SBO.

CONCLUSIONS

Carina-shift has a greater contribution to the formation of RS at SBO after FKI. The pre-procedure IVUS provides helpful information for predicting the RS after FKI.

Classic crush and DK crush stenting techniques

Clinical data have supported the advantages of the double kissing (DK) crush technique, which consists of stenting the side branch (SB), balloon crush, first kissing, stenting the main vessel (MV) and final kissing balloon inflation, for complex coronary bifurcation lesions compared to other stenting techniques. Careful rewiring from the proximal cell of the MV stent to make sure the wire is in the true lumen of the SB stent is key to acquiring optimal angiographic results. Balloon anchoring from the MV, alternative inflation and each kissing inflation using large enough non-compliant balloons at high pressure, and the proximal optimisation technique are mandatory to improve both angiographic and clinical outcomes. Stratification of a given bifurcation lesion is recommended before decision making.

A Y-shaped bifurcation-dedicated stent for the treatment of de novo coronary bifurcation lesions: an IVUS analysis from the BRANCH trial

AIMS

The aim of this IVUS substudy was to assess the efficacy of the Y-shaped Medtronic bifurcation-dedicated stent (BDS) for the treatment of de novo coronary bifurcated lesions.

METHODS AND RESULTS

In the BRANCH trial, post-procedure IVUS was performed in 45 patients. IVUS was available in both branches in 19 lesions and only the main branch (MB) in 26 lesions. IVUS analysis included four distinct locations: proximal MB, bifurcation site, distal MB, and side branch (SB). Lumen symmetry was calculated as minimum/maximum lumen diameters. The quantity of isolated stent struts across the SB ostium was used to assess inadequate strut apposition to the carina resulting in partial jailing of the SB orifice. A minimum stent area (MSA) <4 mm2 was found in 0% of proximal and distal MB, and in 15.4% of SB. In SB, MSA was located mainly at mid or distal segments (84.6%), rather than at the SB ostium. Eccentric stent expansion and edge dissection were seen primarily at proximal MB. Isolated struts were seen in only 20.9% of SB ostia with a minimum length of 0.7±0.4 mm.

CONCLUSIONS

Implantation of BDS resulted in adequate stent dimensions and strut apposition at the carina and SB ostium. ClinicalTrials.gov Identifier: NCT00607321.

Mechanism of luminal patency of the self-expanding Sideguard sidebranch stent: evaluation by intravascular ultrasound and optical coherence tomography

BACKGROUND

The Cappella Sideguard (CS) sidebranch stent is a self-expanding, thin-strut, nitinol device with anatomic flaring at the sidebranch ostium designed to treat bifurcation lesions.

OBJECTIVE

To evaluate the mechanism of long-term lumen patency of the novel, self-expanding CS sidebranch stent compared with a balloon-expandable stent in the main vessel.

METHODS

We performed intravascular ultrasound postintervention and at follow-up in 24 CS stents and in 28 balloon-expandable drug-eluting stents deployed in the corresponding main vessel. Thirteen patients also had optical coherence tomography (OCT) at follow-up to evaluate neointimal hyperplasia and strut coverage.

RESULTS

CS stent area at the sidebranch carina increased significantly from 3.8 ± 1.2 mm(2) postintervention to 4.6 ± 1.2 mm(2) at follow-up (P < 0.001), resulting in no change in lumen area (3.8 ± 1.2 mm(2) to 3.7 ± 1.2 mm(2) , P = 0.72) despite a neointimal area at follow-up of 0.9 ± 0.8 mm(2) . Volumetric changes were similar, and the distribution of neointimal hyperplasia peaked 1-2 mm distal to the carina. Change of lumen volume inversely correlated to the neointimal volume (R = -0.48, P < 0.001), but correlated positively to the change in stent volume (R = 0.52, P < 0.0001). By OCT, most CS struts were covered (100% [98.9, 100]) at the bifurcation site, whereas 61% of floating DES struts that crossed the sidebranch were covered by smooth tissue with a similar texture compared with neointima.

CONCLUSION

Although neointimal hyperplasia accumulates within the CS stent mainly 1-2 mm distal to the carina, the self-expanding CS stent may be effective in maintaining an adequate patency in the sidebranch by continued stent expansion noted at follow-up.

Impact of the complexity of bifurcation lesions treated with drug-eluting stents: the DEFINITION study (Definitions and impact of complEx biFurcation lesIons on clinical outcomes after percutaNeous coronary IntervenTIOn using drug-eluting steNts)

OBJECTIVES

The present study established criteria to differentiate simple from complex bifurcation lesions and compared 1-year outcomes stratified by lesion complexity after provisional stenting (PS) and 2-stent techniques using drug-eluting stents.

BACKGROUND

Currently, no criterion can distinguish between simple and complex coronary bifurcation lesions. Comparisons of PS and 2-stent strategies stratified by lesion complexity have also not been reported previously.

METHODS

Criteria of bifurcation complexity in 1,500 patients were externally tested in another 3,660 true bifurcation lesions after placement of drug-eluting stents. The primary endpoint was the occurrence of a major adverse cardiac event (MACE) at 12 months. The secondary endpoint was the rate of stent thrombosis (ST).

RESULTS

Complex (n = 1,108) bifurcation lesions were associated with a higher 1-year rate of MACE (16.8%) compared with simple (n = 2,552) bifurcation lesions (8.9%) (p < 0.001). The in-hospital ST and 1-year target lesion revascularization rates after 2-stent techniques in the simple group (1.0% and 5.6%, respectively) were significantly different from those after PS (0.2% [p = 0.007] and 3.2% [p = 0.009], respectively); however, 1-year MACE rates were not significantly different between the 2 groups. For complex bifurcation lesions, 2-stent techniques had lower rates of 1-year cardiac death (2.8%) and in-hospital MACE (5.0%) compared with PS (5.3%, p = 0.047; 8.4%, p = 0.031).

CONCLUSIONS

Complex bifurcation lesions had higher rates of 1-year MACE and ST. The 2-stent and PS techniques were overall equivalent in 1-year MACE. However, 2-stent techniques for complex lesions elicited a lower rate of cardiac death and in-hospital MACE but higher rates of in-hospital ST and revascularization at 1 year for simple lesions.

Serial intravascular ultrasound observations from the Tryton first-in-man study

AIMS

To report serial intravascular ultrasound (IVUS) findings of bifurcation lesions treated with the dedicated Tryton Side Branch Stent to assess mechanisms of restenosis.

METHODS AND RESULTS

The Tryton FIM study was a multicentre, prospective, single-arm, "first-in-man" study to treat de novo bifurcation lesions. Minimum lumen area (MLA) sites and overall volumes were analysed within main vessels and side branches. Overall, 27 main vessels and 22 side branches had paired baseline and follow-up IVUS. The post-intervention main vessel MLA decreased from 5.3 (4.1, 6.2) to 4.8 (3.4, 5.7) mm2 at follow-up, p=0.02, and the side branch MLA decreased from 3.5 (3.0, 3.8) to 2.5 (2.2, 3.2) mm2, p=0.0005. Stent area at the side branch did not change (mean stent area from 4.0 [3.3, 4.1] to 3.8 [3.4, 4.2] mm3/mm, p=0.95). Neointimal hyperplasia (NIH) net volume obstruction (%) measured 1.8% (0.5, 7.0) for the entire main vessel and 14.9% (2.3, 31.1) for the entire side branch stents. In both main vessel and side branches the decrease in lumen area correlated significantly with NIH.

CONCLUSIONS

Serial IVUS analysis of a new side branch Tryton stent showed no chronic stent recoil. Side branch underexpansion was common and along with superimposed NIH contributed to the reduction in lumen dimensions at follow-up.

Mechanisms, pathophysiology, and clinical aspects of incomplete stent apposition

Incomplete stent apposition (ISA) is characterized by the lack of contact of at least 1 stent strut with the vessel wall in a segment not overlying a side branch; it is more commonly found in drug-eluting stents than bare-metal stents. The accurate diagnosis of ISA, initially only possible with intravascular ultrasound, can currently be performed with higher accuracy by optical coherence tomography, which also enables strut-level assessment due to its higher axial resolution. Different circumstances related both to the index procedure and to vascular healing might influence ISA occurrence. Although several histopathology and clinical studies linked ISA to stent thrombosis, potential selection bias precluded definitive conclusions. Initial studies usually performed single time point assessments comparing overall ISA percentage and magnitude in different groups (i.e., stent type), thus hampering a comprehensive understanding of its relationship with vascular healing. Serial intravascular imaging studies that evaluated vascular response heterogeneity recently helped fill this gap. Some particular clinical scenarios such as acute coronary syndromes, bifurcations, tapered vessels, overlapping stents, and chronic total occlusions might predispose to ISA. Interventional cardiologists should be committed to optimal stent choices and techniques of implantation and use intravascular imaging guidance when appropriate to aim at minimizing acute ISA. In addition, the active search for new stent platforms that could accommodate vessel remodeling over time (i.e., self-expandable stents) and for new polymers and/or eluting drugs that could induce less inflammation (hence, less positive remodeling) could ultimately reduce the occurrence of ISA and its potentially harmful consequences.

Role of intravascular ultrasound in unprotected left main percutaneous coronary intervention

Percutaneous coronary intervention (PCI) to the unprotected left main stem offers an attractive alternative to bypass grafting, but is associated with a significant clinical risk and therefore demands special consideration. Successful left main PCI is dependent upon the morphology of the lesion and the technical quality of the procedure. For these reasons, intravascular ultrasound (IVUS) has been the most popular adjunct to coronary angiography during left main PCI. However, trials of IVUS in left main PCI have produced inconclusive results, and most data predate the use of drug-eluting stents. Despite this, IVUS offers practical benefits in both case selection, and in guiding angioplasty and stenting. Here, we review the arguments for the present and future role of IVUS in left main PCI.

Intravascular ultrasound comparison of the self-expanding Sideguard stent in the side branch versus a balloon-expandable stent in the main vessel to assess mechanisms of acute lumen gain in bifurcation lesions

OBJECTIVES

We compared the mechanisms of lumen gain after Cappella Sideguard (CS) side branch (SB) bifurcation stent deployment versus a balloon-expandable stent in the corresponding main vessel (MV).

BACKGROUND

The novel CS SB bifurcation stent is a self-expanding, thin-strut, nitinol device with anatomic flaring at the SB ostium.

METHODS

In 28 bifurcation lesions, intravascular ultrasound imaging of both the SB and the MV was performed both pre- and postintervention; vessel and lumen areas were measured every 1 mm over a 5 mm segment beginning at the carina.

RESULTS

Although minimum lumen area (MLA) within the distal 5 mm segment beginning at the carina increased from 2.8 ± 1.3 mm(2) to 3.8 ± 1.1 mm(2), P < 0.001, in the SB and from 3.4 ± 1.4 mm(2) to 6.0 ± 1.1 mm(2), P < 0.001, in the MV, stent expansion (minimum stent area/distal reference lumen area) was significantly less in the SB compared with the MV (77.8 ± 21.3% vs. 91.6 ± 18.4%, P = 0.02). Post stenting, the MLA site was located at the carina more frequently in the SB (85.7%) than in the MV (60.7%), P = 0.04. Plaque volume in the 5 mm proximal to carina in the MV tended to decrease, whereas plaque volume in the SB increased slightly with no change in overall plaque volume in the 5-mm-long segment distal to the carina in the MV, suggesting plaque shift from the proximal MV to the SB.

CONCLUSIONS

Acute CS lumen gain is less than the lumen gain of a balloon-expandable stent in the MV because of less aggressive acute expansion and/or the plaque shift from the proximal MV to the SB.

Vessel remodeling and plaque distribution in side branch of complex coronary bifurcation lesions: a grayscale intravascular ultrasound study

To investigate vessel remodeling and plaque distribution in side branch (SB) of true coronary bifurcation lesions with SB disease extending from its ostium. A total of 62 patients with single de novo true bifurcation lesions with SB with severe and extensive disease were enrolled. Of that, 45 patients/lesions underwent pre-intervention intravascular ultrasound (IVUS) at the SB. Left anterior descending was the most prevalent target vessel (>85%). All lesions had significant involvement of both branches of the bifurcation, and the majority were classified as type 1,1,1 according to the Medina classification. Considering the subset with IVUS imaging, mean lesion length, reference diameter and % diameter stenosis in the SB were 8.88 ± 4.61 mm, 2.68 ± 0.59, and 70.2 ± 16.0%, respectively. Also, mean proximal (take-off) and distal (carina) angles were 142.3 ± 21.9° and 60.7 ± 22.4°, respectively. At minimum lumena area (MLA) site, mean external elastic membrane and MLA cross-sectional areas were 6.70 ± 2.08 and 1.87 ± 0.93 mm2, respectively; given that the mean distance measured between the SB origin and MLA site was <1 mm. In addition, mean plaque burden was 67.9% and mean remodeling index was 0.78 ± 0.21. Importantly, only 9 cases out of 45 presented remodeling index > 1.0. Also, plaque distribution analysis within the SB ostium demonstrated preferable plaque positioning in the opposite side to the flow divider. In conclusions, significant negative remodeling is a frequent encounter in SB of complex coronary bifurcation lesions presenting with extensive and severe disease; in addition, plaque distribution in the SB ostium appears to be asymmetric in relation to the parent vessel, as plaque burden is mostly found in regions of low wall shear stress including the opposite side to the flow divider within the bifurcation anatomy.

Modified flower petal technique: a new technique for the treatment of Medina type 1.1.1 coronary bifurcation lesions

OBJECTIVES

This study sought to propose a new technique for the treatment of Medina type 1.1.1 bifurcation lesions.

BACKGROUND

Although there are many different 2-stent techniques, the optimal strategy for patients with Medina type 1.1.1 bifurcation lesions has not yet been determined.

METHODS

The authors selected 30 patients who had Medina type 1.1.1 coronary bifurcation lesions. The most important characteristics of this new technique are complete coverage of the side branch (SB) ostium by stent struts and lower metallic burden at carina region. All procedures were performed using drug-eluting stents. All patients were followed up to 9 months after the intervention. Quantitative coronary angiography (QCA) analyses were performed for both the main and the side branches at baseline, after stent implantation, and at 9-month follow-up.

RESULTS

Procedural success rate was 100%. Final kissing balloon inflation could be performed in all patients. There was no major adverse cardiac events during hospital stay. Clinical and angiographic QCA follow-up was available in 28 patients (93.4%). There was no death, myocardial infarction, or stent thrombosis at 9 months follow-up. In-stent restenosis requiring reintervention was noted at the SB ostium in only 1 patient.

CONCLUSIONS

This new "modified flower petal" technique has several advantages for stent implantation of Medina type 1.1.1 bifurcation lesions over the available techniques: complete coverage of the SB ostium, lower metallic burden at the carina, and excellent immediate and midterm clinical outcomes.

Three-dimensional intravascular ultrasound evaluation of carina and plaque shift at the distal left main coronary artery bifurcation after treatment with a one-stent cross-over technique

OBJECTIVE

To assess the geometrical changes in the distal left main coronary artery (LMCA), left anterior descending (LAD), and left circumflex (LCX) that occur after a distal LMCA lesion is treated using a one-stent cross-over strategy.

BACKGROUND

Morphological changes after stent implantation into distal LMCA lesions are not fully understood.

METHODS

We used pre- and postintervention three-dimensional intravascular ultrasound of both the LAD and LCX as well as of the LMCA to evaluate distal LMCA lesions after a 1-stent cross-over strategy. In 38 distal LMCA bifurcation lesions, cross-sectional measurements were performed every 1 mm over a 5-mm segment in the LAD and LCX distal to the carina and over the entire LMCA proximal to the carina.

RESULTS

The increase in lumen volume correlated with the increase in external elastic membrane volumes: R = 0.917, P < 0.001, in the LMCA and R = 0.785, P < 0.001, in the LAD with no decrease in plaque volume except at the distal end of the LMCA (P = 0.081) and at the LAD carina (P = 0.11). The LCX lumen area decreased significantly at the LCX carina from 5.9 ± 2.0 mm(2) to 5.3 ± 1.9 mm(2) (P < 0.01); however, the response was variable from a 4.0 mm(2) decrease to a 1.8 mm(2) increase in lumen area. While the change in LCX lumen area at the carina correlated with the change in vessel area (R = 0.791, P < 0.001), there was also a small increase in plaque area at the LCX carina from 6.4 ± 2.9 mm(2) to 6.8 ± 2.9 mm(2) (P < 0.01).

CONCLUSIONS

LMCA bifurcation lumen changes after cross-over single-stent implantation were determined primarily by conformational changes in vessel geometry.

Comparison of 3-year clinical outcomes between classic crush and modified mini-crush technique in coronary bifurcation lesions

OBJECTIVES

We aimed to compare long-term clinical outcomes between modified mini-crush (modi-MC) technique with classic crush (crush) technique for treatment of bifurcation lesions.

BACKGROUND

The modi-MC technique showed excellent procedural success and favorable 9-month clinical outcomes.

METHODS

From January 2005 to November 2009, we enrolled patients with de novo bifurcation lesions treated with modi-MC (n = 112 lesions in 111 patients) and crush technique (n = 69 lesions in 67 patients). Primary endpoint was rate of major adverse cardiac events (MACE), a composite of all-cause death, myocardial infarction (MI), and target lesion revascularization (TLR) at 3 years.

RESULTS

There was no significant difference in baseline characteristics. The modi-MC technique showed a significantly higher success rate of final kissing balloon inflation (84.1 vs. 98.2%, P = 0.001). After 3 years, MACE rate was significantly lower in the modi-MC group (25.4 vs. 12.6%, P = 0.030). The incidence of all-cause death was 7.5 vs. 2.7% (P = 0.087), MI was 4.5 vs. 1.8% (P = 0.290), TLR was 17.4 vs. 8.9% (P = 0.093) and stent thrombosis was 3.0 vs. 1.8% (P = 0.632) in the crush and modi-MC groups, respectively.

CONCLUSIONS

The modified mini-crush technique showed more favorable 3-year clinical outcomes compared to the classic crush technique.

Intravascular ultrasound-guided systematic two-stent techniques for coronary bifurcation lesions and reduced late stent thrombosis

BACKGROUND

The effects of intravascular ultrasound (IVUS)-guided complex approaches using drug-eluting stents (DES) for coronary bifurcation lesions on clinical outcomes has not yet been studied in detail.

OBJECTIVE

Our objective was to analyze the difference in 1-year outcomes following two-stent techniques involving implantation of DES for coronary bifurcation lesions between IVUS-guided and angiography-guided groups.

METHODS

From May 26, 2007 to March 24, 2010, 628 patients received two-stent techniques (324 in the IVUS-guided group and 304 angiography-guided) and were prospectively studied. We compared major adverse cardiac events (MACE, including cardiac death, stent thrombosis [ST], myocardial infarction [MI] and target lesion/vessel revascularization) at 12-months follow-up, before and after adjusting for propensity score matching.

RESULTS

At 12-months after the indexed procedure, patients in the angiography-guided group had significantly increased in-stent restenosis. Compared to the angiography-guided group, the IVUS-guided group had a significantly lower overall unadjusted ST rate (1.2% vs. 6.9%, P < 0.001), definite ST (0.6% vs. 5.3%, P < 0.001), late ST (0.6% vs. 4.3%, P = 0.003), MI (4.6% vs. 8.9%, P = 0.038) and cardiac death (0.9% vs. 3.3%, P = 0.049). By propensity score matching, 123 paired patients were matched. The late ST at 12-months follow-up was 0% in the IVUS-guided group versus 4.9% in the angiography-guided group (P = 0.029), resulting in significant differences in ST-elevation MI between the two groups (2.4% vs. 9.8%, P = 0.030).

CONCLUSIONS

The IVUS-guided two-stent technique was associated with significantly reduced late stent thrombosis, with a resultant reduction in ST-elevation MI. © 2012 Wiley Periodicals, Inc.

Clinical and Procedural Predictors of Suboptimal Outcome After the Treatment of Drug-Eluting Stent Restenosis in the Unprotected Distal Left Main Stem

Background—

Few data are available regarding the optimal revascularization strategy for unprotected distal left main coronary artery (UDLM) in-stent restenosis (ISR).

Methods and Results—

Between April 2002 and December 2008, UDLM-ISR following drug-eluting stent (DES) implantation occurred in 92 of 474 patients (19.4%). Of these, 8 (8.7%) who underwent a coronary artery bypass graft (CABG) were excluded, and the remaining 84 (91.3%) who underwent percutaneous coronary intervention (PCI) (43 plain old balloon angioplasty [POBA] and 41 DES) were analyzed to assess the feasibility of PCI for UDLM-ISR. The overall cardiac death, myocardial infarction (MI), and major adverse cardiac events during the follow-up period (median, 24 months) occurred in 4, 2, and 31 patients, respectively. Repeat target lesion revascularization (TLR) occurred in 28 patients. The incidence of repeat TLR was higher following PCI with POBA than with DES (hazard ratio [HR], 2.79; 95% CI, 1.23–6.34; P =0.014). On Cox regression analysis, the independent predictors of repeat TLR were treatment with POBA (HR, 3.29; 95% CI, 1.41–7.69; P =0.006) and EuroSCORE (European System for Cardiac Operative Risk Evaluation) >6 (HR, 2.53; 95% CI, 1.02–6.28; P =0.045). More complex lesions requiring a 2-stent strategy were associated with a higher occurrence of TLR for restenosis of the left circumflex coronary artery ostium (LCX-ISR) (HR, 2.51; 95% CI, 1.59–3.97; P =0.001) as well as repeat TLR for recurrent LCX-ISR (HR, 4.32; 95% CI, 0.97–19.20; P =0.05) compared to a 1-stent strategy. No cardiac death at 2 years occurred in patients with LCX-ISR.

Conclusions—

UDLM restenosis is better treated with DES than with POBA. The rate of recurrent ISR following repeat PCI was high, whereas the rates of MI and death were relatively low. Complex lesions requiring a 2-stent strategy had a higher recurrence rate at the ostial LCX but without an associated increased risk of MI and death.

Comparison between measured and calculated length of side branch ostium in coronary bifurcation lesions with intravascular ultrasound

PURPOSE

Accurate evaluation of side branch (SB) ostium could be critical to the treatment of bifurcation lesions. We compared measured and calculated values of side branch ostial length (SBOL) in coronary bifurcation lesions with intravascular ultrasound (IVUS).

MATERIALS AND METHODS

Pre-intervention and post-intervention IVUS was performed in 113 patients who underwent stent implantation of bifurcation lesions. For the IVUS longitudinal reconstruction of the bifurcation lesions, SBOL, SB diameter, and the angle between the distal portion of the main vessel (MV) and SB were directly measured. In addition, SBOL was calculated as: SB diameter/ sin (angle between distal MV and SB). The relationship between measured and calculated SBOL was then evaluated.

RESULTS

The angled between the distal MV and SB were 57.3±12.4° at pre-intervention and 59.4±12.6° at post-intervention. The mean measured and calculated SBOL values were 2.91±0.86 mm and 3.06±0.77 mm at pre-intervention and 2.79±0.82 mm and 2.92±0.69 mm at post-intervention, respectively. Differences between measured and calculated SBOL were 0.15±0.44 mm at pre-intervention and 0.13±0.41 mm at post-intervention. We found that calculated SBOL was correlated with measured SBOL (pre-intervention r=0.863, p<0.001; post-intervention r=0.868, p<0.001).

CONCLUSION

There was a good correlation between measured and calculated SBOLs of the bifurcation lesions in IVUS longitudinal reconstruction. SBOL in the bifurcation lesions can therefore be estimated using the SB diameter and the angle between distal MV and SB.