Relative dependence of diameters of branches in coronary bifurcations after stent implantation in main vessel--importance of carina position

BACKGROUND AND AIM: Bifurcation lesions are relatively frequently encountered in everyday interventional practice. Stenting of the vessel chosen to be main (usually the larger one) frequently leads to stenosis at the ostium of the side branch (SB) and compromises its flow (side branch compromise--SBC). The relative dependence of main and side branch diameters, based on the concept of carina displacement of stent struts, was examined in a cohort of patients with bifurcation stenting. METHODS: We accept that the basic mechanism for SBC after stent placement in the parent vessel is carina shifting from expanded stent struts. The ostial SB minimal lumen diameter (MLD), percentage diameter stenosis (%DS) at maximal and calculated actual carina displacement, as well as distal limb diameter (DLD) in the main branch were calculated and compared with actually observed values. RESULTS: A group of 55 consecutive patients with acceptable quality angiograms formed the study population. General patient characteristics were similar to other bifurcation studies. Left anterior descending artery was predominantly treated in 73% of patients. There was worsening SB ostial stenosis after stent implantation (%DS increase from 48%+/-23% to 69%+/-21%, p <0.001) and final improvement because of kissing balloon inflation or SB postdilatation (post vs. final-69+/-21% and 53+/-25%, p<0.001). Stent implantation causes straightening of the main vessel, evident from a significant increase in angle C (pre- 148 degrees +/-19 degrees vs. 156 degrees +/-16 degrees after stenting, p=0.007). Relations between observed and predicted values for main branch DLD and %DS demonstrated a good correlation between predicted and observed values (for DLD r=0.66, p<0.001, and for %DS r=0.53, p <0.001). There was an excellent fit of regression lines between theoretical predictions and actual measurements for side branches (MLD r=0.91, p<0.001, %DS r=0.89, p<0.001).CONCLUSIONS: Carina displacement from stent struts is a major mechanism governing changes in coronary bifurcations after main vessel stenting. Improvement in the ostium of the side branch causes shifting back of the carina and a decrease of main vessel diameter. The long-term consequences of this phenomenon are not currently known.     

Simultaneous kissing drug-eluting stent technique for percutaneous treatment of bifurcation lesions in large-size vessels.

Treatment of bifurcation lesions is associated with high procedural complications and restenosis rate due to plaque shift, suboptimal angiographic results, difficulty in crossing the stent struts, and incomplete coverage of the side-branch ostium. The simultaneous kissing stent (SKS) technique involves two stents, one in main vessel (MV) and one in the side branch (SB) with overlapping stents in the MV proximally, extending proximally the carina of bifurcation. We analyzed our first 200 consecutive patients (202 lesions) who underwent SKS technique for true bifurcation lesions using sirolimus eluting stents, with a minimum follow-up of 6 months. Procedural success was 100% for MV and 99% for SB using SKS technique, with clinical success rate of 97%. In-hospital and 30-day major adverse cardiac events were 3% and 5%, respectively, with a procedure time of 36 +/- 14 min. At mean follow-up of 9 +/- 2 months, the incidence of target lesion revascularization was 4% in the entire group. Therefore, SKS technique using sirolimus-eluting stents may become an effective treatment strategy for large-size bifurcation lesions. However, in order to establish its superiority, SKS technique needs to be compared in a randomized manner with conventional stent techniques.     

The AST petal dedicated bifurcation stent: first-in-human experience.

The aim of this first-in-human study was to evaluate the feasibility and safety of the novel AST petal side-access bifurcation stent. Outcomes following percutaneous coronary intervention for bifurcations remain inferior to those of nonbifurcated lesions. Even with drug-eluting stents, restenosis occurs especially at the side-branch (SB) ostium. The petal stent uniquely deploys strut elements into the SB, supporting the ostium and carina. The primary endpoint of this 13-patient prospective registry was in-hospital major adverse cardiac events (MACE). Secondary end points included acute minimum lumen diameter (MLD) at the SB ostium, lesion success, device success, procedural success, 30-day MACE, and 4-month SB ostial MLD. The study lesion was successfully treated in 13 patients with the study stent being successfully implanted in 12. Target lesions were left anterior descending coronary artery in nine subjects, left circumflex in three, and right coronary artery in one. In-hospital MACE were limited to two non-Q-wave myocardial infarctions. In-stent main branch MLD increased from a mean of 0.63 +/- 0.45 mm to 2.61 +/- 0.47 mm at the index procedure and for this initial bare metal version of the stent, 4-month mean MLD measured 1.02 +/- 0.42 mm and there was target vessel revascularization on two patients. The feasibility of safely deploying this first-generation petal stent was demonstrated in selected patients with challenging coronary bifurcation lesions. It is a promising platform for drug delivery, with unique scaffolding of the side-branch ostium.     

The Carina Angle—New Geometrical Parameter Associated with Periprocedural Side Branch Compromise and the Long‐Term Results in Coronary Bifurcation Lesions with Main Vessel Stenting Only

Background: The two main problems unresolved in coronary bifurcation stenting are periprocedural side branch compromise and higher restenosis at long term. The purpose of this study is to reveal the link between periprocedural side branch compromise and long‐term results after main vessel stenting only in coronary bifurcations. Methods: Eighty‐four patients formed the study population. The inclusion criteria were good‐quality angiograms, with maximal between‐branch angle opening, no overlap, permitting accurate angiographic analysis. Carina angle (α)—the distal angle between main vessel (MV) before bifurcation and side branch (SB)—was measured pre‐ and poststenting. Clinical follow‐up 9–12 months was obtained with coronary angiography if needed. Results: The patient population was high‐risk with 33% diabetics and 84% two‐ and three‐vessel disease. Ninety‐five stents were implanted in 92 lesions, with three T‐stenting cases. Drug‐eluting stents were implanted in 54%. Kissing‐balloon (KBI) or sequential inflation was performed in 35%. SB functional closure occurred in 17.4%, with independent predictors α < 40° and diameter ratio MB/SB >1.22. After 12±4 months there were five myocardial infarctions (6%) and 13 (15%) target lesion revascularization procedures. Independent predictors of major cardiovascular events were carina angle <40°, MB lesion length >8 mm, negative change of between‐branch angle, DES usage, and KBI. Conclusions: Smaller carina angle with straightening of MV—main branch from stent implantation in coronary bifurcations predicted higher SB compromise, restenosis, and MACE rates during follow‐up of 1 year.     

Preintervention angiographic and intravascular ultrasound predictors for side branch compromise after a single-stent crossover technique

A single stent crossover technique is the most common approach to treating bifurcation lesions. In 90 bifurcation lesions with side branch (SB) angiographic diameter stenosis <75%, we assessed preintervention intravascular ultrasound (IVUS; of main branch [MB] and SB) predictors for SB compromise (fractional flow reserve [FFR] <0.80) after a single stent crossover. Minimal lumen area (MLA) was measured within each of 4 segments (MB just distal to the carina, polygon of confluence, MB just proximal to polygon of confluence, and SB ostium). All lesions showed Thrombolysis In Myocardial Infarction grade 3 flow in the SB after MB stenting. Although angiographic diameter stenosis at the SB ostium increased from 26 ± 15% before the procedure to 36 ± 21% after stenting (p = 0.001), FFR <0.80 was observed in only 16 patients (18%). Negative remodeling (remodeling index <1) was seen in 83 (92%) lesions but did not correlate with FFR after stenting. Independent predictors for FFR after stenting were maximal balloon pressure (p = 0.002) and MLA of SB ostium before percutaneous coronary intervention (p <0.001), MLA within the MB just distal to the carina (p = 0.025), and plaque burden at the SB ostium before percutaneous coronary intervention (p = 0.005), but not angiographic poststenting diameter stenosis or minimal lumen diameter. For prediction of FFR <0.80 after percutaneous coronary intervention, the best cutoff of MLA within the SB ostium before percutaneous coronary intervention was 2.4 mm(2) (sensitivity 94%, specificity 69%). Also, the cutoff of plaque burden within the SB ostium before percutaneous coronary intervention was ≥51% (sensitivity 75%, specificity 71%). In 67 lesions with an MLA ≥2.4 mm(2) or plaque burden <50% before percutaneous coronary intervention, 63 (94%) showed FFR ≥0.80. However, FFR <0.80 was seen in only 12 (52%) of 23 lesions with an MLA <2.4 mm(2) and plaque burden ≥50%. In conclusion, there do not appear to be reliable IVUS predictors of functional SB compromise after crossover stenting.     

Single String Technique for Coronary Bifurcation Stenting: Detailed Technical Evaluation and Feasibility Analysis

ObjectivesThe study aimed to evaluate the adequacy and feasibility of the single string bifurcation stenting technique.BackgroundDouble-stent techniques may be required for complex bifurcations. Currently applied methods all have their morphological or structural limitations with respect to wall coverage, multiple strut layers, and apposition rate.MethodsSingle string is a novel method in which, first, the side branch (SB) stent is deployed with a single stent cell protruding into the main branch (MB). Second, the MB stent is deployed across this protruding stent cell. The procedure is completed by final kissing balloon dilation. The single string technique was first tested in vitro (n = 20) and next applied in patients (n = 11) with complex bifurcation stenoses.ResultsAll procedures were performed successfully, crossing a single stent cell in 100%. Procedure duration was 23.0 ± 7.9 min, and the fluoroscopy time was 9.4 ± 3.5 min. The results were evaluated by optical coherence tomography, showing fully apposed struts in 83.0 ± 9.2% in the bifurcation area. Residual area obstruction in the MB was 6.4 ± 5.6% and 25.0 ± 16.9% in the SB, as evaluated by micro computed tomography. All the human cases were performed successfully with excellent angiographic results: the residual area stenosis was 27 ± 8% and 29 ± 10% in the MB and in the SB, respectively, by 3-dimensional quantitative coronary angiography. No relevant periprocedural enzyme increase was observed. During follow-up (6 ± 4 months), no adverse clinical events (death, myocardial infarction, target vessel revascularization) were noted.ConclusionsThe single string technique for complex bifurcation dilation was shown to be adequate in vitro and feasible in humans, with favorable results in terms of stent overlap, malapposition rate, and low residual obstruction in both the MB and SB.     

A New Stent Design for the Treatment of True Bifurcation Lesions: H-Side Branch Stents

Background: There has been much debate for the adequate treatment strategies for true bifurcation lesions. The purpose of this study is to introduce and test a novel stent design for the treatment of true bifurcation lesions.
Methods: This side branch stent is composed of three parts: proximal, connecting, and distal parts. The distal part for the side branch vessel has a slope-side stent margin for circumferential coverage of the ostium and one radio-opaque marker for targeting the carina. The proximal part with two radio-opaque markers operates for safe stent delivery and useful guidance for a more precise placement of the distal part on the side branch ostium. Results of the in vitro test in the acrylic resin-made bifurcation phantom model were evaluated with microcomputer tomography. Animal experiments with this new stent platform were also performed in five pigs.
Results: In vitro test and microcomputer tomography showed complete coverage of the side branch ostium circumferentially with stent struts, and the absence of stent struts in the main vessel above the side branch ostium level. This side branch stents were successfully deployed in all 5 pigs. The results of animal experiments were also similar to those of in vitro tests.
Conclusions: In vivo and vitro tests demonstrated the effective modality of this side branch stent for the treatment of true bifurcation lesions. (J Interven Cardiol 2010;23:54–59)     

Bifurcation coronary lesions treated with the "crush" technique: an intravascular ultrasound analysis

OBJECTIVES: We report intravascular ultrasound (IVUS) findings after crush-stenting of bifurcation lesions. BACKGROUND: Preliminary results with the crush-stent technique are encouraging; however, isolated reports suggest that restenosis at the side branch (SB) ostium continues to be a problem. METHODS: Forty patients with bifurcation lesions underwent crush-stenting with the sirolimus-eluting stent. Postintervention IVUS was performed in both branches in 25 lesions and only the main vessel (MV) in 15 lesions; IVUS analysis included five distinct locations: MV proximal stent, crush area, distal stent, SB ostium, and SB distal stent. RESULTS: Overall, the MV minimum stent area was larger than the SB (6.7 +/- 1.7 mm2 vs. 4.4 +/- 1.4 mm2, p < 0.0001, respectively). When only the MV was considered, the minimum stent area was found in the crush area (rather than the proximal or MV distal stent) in 56%. When both the MV and the SB were considered, the minimum stent area was found at the SB ostium in 68%. The MV minimum stent area measured <4 mm2 in 8% of lesions and <5 mm2 in 20%. For the SB, a minimum stent area <4 mm2 was found in 44%, and a minimum stent area <5 mm2 in 76%, typically at the ostium. "Incomplete crushing"--incomplete apposition of SB or MV stent struts against the MV wall proximal to the carina--was seen in >60% of non-left main lesions. CONCLUSIONS: In the majority of bifurcation lesions treated with the crush technique, the smallest minimum stent area appeared at the SB ostium. This may contribute to a higher restenosis rate at this location.     

Analysis of left main coronary artery bifurcation lesions treated with biolimus‐eluting DEVAX AXXESS plus nitinol self‐expanding stent: Intravascular ultrasound results of the AXXENT trial

Objective: To assess the efficacy of the AXXESS stent on the treatment of left main coronary artery (LMCA) bifurcation lesions using IVUS. Background: The treatment of LMCA bifurcation lesions remains challenging even with the use of drug‐eluting stents. The AXXESS system is a biolimus A9‐eluting self‐expanding stent, dedicated to the treatment of bifurcation lesions. Methods: Data were obtained from the AXXENT trial, a prospective, single‐arm, multicenter study designed to evaluate the efficacy of the AXXESS stent on the treatment of LMCA bifurcation lesions. IVUS was available in 26 cases at 6‐months follow‐up. Volumetric and cross‐sectional analyses within the AXXESS stent, and cross‐sectional analyses at the ostia of left anterior descending (LAD) and left circumflex coronary arteries (LCX) were performed. Results: Within the AXXESS stent, percent neointimal volume obstruction was (3.0 ± 4.1)% with a minimal lumen area of 10.3 ± 2.6 mm². AXXESS stent volume showed an 12.4% increase at follow‐up compared with postprocedure (P = 0.04). Lumen area was significantly smaller in the LCX ostium compared with the LAD ostium at follow‐up (3.6 ± 1.3 mm² vs. 5.5 ± 2.0 mm², P = 0.0112). There was greater neointimal formation in the LCX ostium compared with the LAD ostium (1.37 ± 1.20 mm² vs. 0.30 ± 0.36 mm², P = 0.0003). Conclusions: The AXXESS stent in the LMCA showed enlargement through 6‐months follow‐up and significant neointimal suppression. Greater neointimal formation and relatively inadequate stent expansion may contribute to luminal narrowing in the LCX ostium. © 2008 Wiley‐Liss, Inc.     

Favorable strategy for the ostial lesion of the left anterior descending coronary artery: Influence on narrowing of circumflex coronary artery

We examined the effectiveness of Palmaz-Schatz (P-S) stent and directional coronary atherectomy (DCA) in ostial lesions of left anterior descending arteries (LAD). The P-S stent was implanted in 11 cases at LAD ostial lesions, and DCA was performed in 13 cases. Percent stenosis and vessel diameter at the target site and the ostium of the circumflex coronary artery (LCX) were measured before and after the procedure. The initial success rate was 100% in both groups. No major complication occurred. LAD ostial lesions were improved from 81.3 ± 3.4% to −8.1 ± 5.7% by P-S stent and from 82.8 ± 2.6% to −2.7 ± 3.9% by DCA. LCX ostial vessel diameter was not changed by DCA (from 3.0 ± 0.2 mm to 3.1 ± 0.3 mm); however, it was significantly decreased by P-S stent (from 2.9 ± 0.2 mm to 2.6 ± 0.2 mm, P < 0.01). When the angle of LAD and LCX was ≦80° from the view of RAO 30° and Caudal 30°, the LCX ostium was significantly narrowed by stenting at LAD ostium (P < 0.01). These findings indicate that both the P-S stent and DCA are effective and safe therapies for LAD ostial lesions in cases with LAD-LCX angle >80°. In cases with LAD-LCX angle ≦80°, however, DCA is a favored therapy rather than P-S stenting to avoid narrowing of the LCX ostium. Cathet. Cardiovasc. Diagn. 43:95–100, 1998. © 1998 Wiley-Liss, Inc.     

Jailed 球囊保护在冠状动脉分叉病变处理中的初步应用

目的：探讨Jailed球囊技术在冠状动脉分叉病变主支血管支架加分支血管备选T-支架处理中的作用。方法对57例接受主支血管支架加分支血管备选T-支架治疗的患者临床资料和冠状动脉介入治疗过程记录的DICOM格式的造影录像进行分析,测定治疗前后主支血管病变处与分支血管开口的最小直径、主支与分支血管夹角,计算术前和术后变化差值,并作Jailed球囊与Jailed导丝组之间的比较。结果共有57例60个分叉病变接受Jailed导丝（39例）或Jailed球囊（18例）分支保护下的主支血管支架植入手术。Jailed导丝组发生分支血管闭塞3例,TIMI血流≤2级的5例,Jailed球囊组分支血管闭塞1例。分支血管开口最小直径术后与术前变化差值Jailed导丝组为（-0.34±0.39）mm,Jailed球囊组为（0.08±0.64）mm,差异有显著统计学意义（t=3.144,P＜0.01）。分叉血管夹角术后Jailed导丝组缩小,Jailed球囊组增大,变化值差异有显著统计学意义[（-3.82±9.04）°、（3.54±7.76）°;t=3.102,P＜0.01]。结论在冠状动脉分叉病变主支血管支架加分支血管备选T-支架治疗中,Jailed球囊技术有利于防范分支血管开口严重挤压甚或闭塞的发生。     

Limited balloon expansion through the struts of the Palmaz-Schatz and NIR stents compared with the Multi-Link stent

After placing a stent in the main vessel of a bifurcation lesion, it is sometimes necessary to perform further balloon inflation in order to treat an ostial lesion in a side branch. The stent struts may prevent full balloon expansion at the ostium of a side branch, resulting in residual ostial stenosis. The degree of completeness of balloon inflation may vary significantly depending on the stent design and structure. A model of a bifurcation lesion with an angle of 45 degrees was created from acrylic resin. The diameters of the main vessel and the side branch were both 3.5 mm. Deployment of the Palmaz-Schatz stent (n=5), NIR stent (n=5) or Multi-Link stent (n=5) was performed in the main vessel with a 3.5-mm balloon catheter inflated to 12 atm. A 3.5-mm balloon catheter was then inflated to 12 atm through the stent struts of the main vessel and into the ostium of the side branch. The degree of completeness of balloon inflation (% balloon expansion) was calculated as (smallest diameter of balloon catheter/reference diameter of balloon catheter) x 100%. The minimal lumen diameter (MLD) and cross-sectional area (CSA) at the ostium of the side branch created with the stent struts were also measured. Limited balloon expansion through the struts was observed with the Palmaz-Schatz stent and the NIR stent, but almost full balloon expansion was observed with the Multi-Link stent (% balloon expansion: Palmaz-Schatz stent 80%, NIR stent 60%, Multi-Link stent 94%, p<0.01). The MLD and CSA of the dilated struts, representing the ostium of the side branch, of the Palmaz-Schatz stent (2.2+/-0.1 mm, 4.5+/-0.3 mm2) and the NIR stent (1.8+/-0.1 mm, 3.1+/-0.3 mm2) were significantly smaller compared with those of the Multi-Link stent (3.0+/-0.2 mm, 8.4+/-0.6 mm2) (p<0.01). The struts of the Palmaz-Schatz stent and the NIR stent deployed in the main vessel of a bifurcation prevent full expansion of a balloon catheter inflated at the side branch ostium. In contrast, almost full balloon expansion through the struts of the Multi-Link stent is achieved.     

Evaluation of a Bifurcation Drug‐Eluting Stent System versus Provisional T‐Stenting in a Perfused Synthetic Coronary Artery Model

Background: Provisional T‐stenting is a widely used strategy for the treatment of coronary artery bifurcation lesions. However, the use of conventional stents in this setting is limited by multiple factors; this includes technical considerations such as wire wrap when accessing the involved vessel, and stent overlap at or near the carina of the lesion. In addition, current slotted tube stent technology tends to be associated with gaps in the coverage of the side branch ostium, which may result in restenosis in that segment of the lesion. The Pathfinder device, now more commonly referred to as the Xience Side Branch Access System (Xience SBA) is a drug‐eluting stent (DES) designed specifically to assist in the treatment of bifurcation lesions by allowing wire access into the side branch, irrespective of the treatment strategy to be employed. Methods: The Xience SBA drug‐eluting stent was compared with the standard Vision coronary stent system using a provisional T‐stenting strategy in a perfused synthetic model of the coronary vasculature with side branch angulations of 30°, 50°, 70°, and 90°. Stent delivery was performed under fluoroscopic guidance. Following the procedure, high‐resolution 2D Faxitron imaging was used to evaluate deployment accuracy of the side branch stent relative to the main branch stent. Results: Deployment of the Xience SBA was accomplished in the same total time as the standard stents in a provisional T‐stenting approach (14.9 vs. 14.6 minutes). However, the time required to achieve stent deployment in the main branch was less with the Xience SBA (4.0 vs. 6.6 minutes), and as a result, total contrast usage (49.4 vs. 69.4 cm³) and fluoroscopy time (5.1 vs. 6.2 minutes) was lower. Additionally, the Xience SBA had a lower incidence of wire wrap (22% vs. 89%) and less distal protrusion of the side branch stent into the main branch (0.54 vs. 1.21 mm). Significant gaps in ostial side branch coverage were not seen in either group. Conclusions: The Xience Side Branch Access DES is a viable device for consistently accessing coronary bifurcation lesions; it allows for easy wire access into the side branch. This may assist the operator in overcoming those well‐recognized limitations associated with use of standard one‐ or two‐stent strategies. In this perfused synthetic coronary model, Xience SBA deployment required less contrast usage and shorter fluoroscopy times. Further testing of this device is warranted.     

Immediate results of bifurcational stenting assessed with optical coherence tomography

Background : A tubular stent may adapt with difficulty to coronary bifurcation lesions (CBLs). Methods : Time domain or frequency domain (FD) optical coherence tomography (OCT) was performed to assess strut apposition immediately after stent implantation across four segments inside the bifurcation, in a consecutive series of patients. OCT pullbacks were performed in the main vessel (MV). Results : A total of 13,142 struts in 45 CBL in 41 patients were assessed. Strut malapposition was significantly more frequent in the half bifurcation facing the side‐branch (SB) ostium (42.9%) than in the proximal segment of the bifurcation 11.8%, half bifurcation opposite the SB 6.7%, or the distal segment 5.7% (all P < 0.0001). Lesions (n = 15) treated with stenting of both MV and SB had a total higher rate of malapposition than those (n = 30) treated with stenting of the MV only (17.6% vs. 9.5%; P = 0.0014). In latter group, lesions treated with FD‐OCT‐guided stent implantation (n = 13) presented a lower rate of malapposition than those treated with conventional angiographic‐guided stent implantation (n = 17) (7.1% vs. 17.5%; P = 0.005). Conclusions : In CBL, strut malapposition is particularly high at the SB ostium. However, a strategy of stenting MV only with adjunctive FD‐OCT guidance is associated with lower rates of malapposition. © 2012 Wiley Periodicals, Inc.     

Double-Kissing Nanocrush for Bifurcation Lesions: Development,Bioengineering, Fluid Dynamics,and Initial Clinical Testing

BackgroundWhen possible, a single-stent technique to treat coronary bifurcation disease is preferable. However, when 2 stents are required, there is scope to improve on existing techniques. The crush technique has already been improved with the introduction of double-kissing (DK) and minicrush. We sought to refine and simplify the minicrush technique, retaining its advantages while avoiding its disadvantages, by developing a DK nanocrush technique.MethodsThe DK nanocrush method allows complete lesion coverage of a bifurcation lesion without excessive metal layers. This is achieved by positioning the side branch (SB) stent with minimal protrusion into the main branch (MB), implantation of the SB stent with an undeployed balloon in the MB, immediate kissing-balloon inflation with formation of a minimal neocarina, stenting the MB, recrossing the proximal part of the SB without crossing a double metal layer, and final kissing. We demonstrate this technique with benchtop implantation, microscopic computed tomographic reconstruction, computational fluid dynamics (CFD) modelling, and clinically with the use of angiographic and intravascular imaging.ResultsThe DK nanocrush was practically feasible and resulted in full ostial coverage. CFD analysis demonstrated minimally disturbed blood flow. The technique was successfully utilised in 9 patients with bifurcation lesions with excellent angiographic outcomes and no adverse events over 12 months.ConclusionsThe DK nanocrush technique may represent the ultimate refinement of the original crush technique with a number of practical and theoretical advantages. It remains to be tested against other bifurcation techniques in prospective trials.     

Serial intravascular ultrasound analysis comparing double kissing and classical crush stenting for coronary bifurcation lesions

Background : Compared with the classical crush, double kissing (DK) crush improved outcomes in patients with coronary bifurcation lesions. However, there is no serial intravascular ultrasound (IVUS) comparisons between these two techniques. Objectives : This study aimed to analyze the mechanisms of the two crush stenting techniques using serial IVUS imaging. Methods : A total of 54 patients with IVUS images at baseline, post‐stenting and eight‐month follow‐up were classified into classical (n = 16) and DK (n = 38) groups. All patients underwent final kissing balloon inflation (FKBI). Unsatisfactory kissing (KUS) was defined as the presence of wrist or >20% stenosis during FKBI at the side branch (SB) ostium. The vessels at bifurcation lesions were divided into the proximal main vessel (MV) stent, the crushed segment, the distal MV stent, the SB ostium and the SB stent body. Results : KUS and incomplete crushing were commonly observed in the classical group (62.5%, 81.3%), compared with DK group (18.0%, 39.5%, P < 0.001 and P = 0.004). The post‐stenting stent symmetry in the classical group was 71.85 ± 7.69% relative to 85.93 ± 6.09% in DK group (P = 0.022), resulting in significant differences in neointimal hyperplasia (NIH, 1.60 ± 0.21 mm² vs. 0.85 ± 0.23 mm², P = 0.005), late lumen loss (1.31 ± 0.81 mm² vs. 0.55 ± 0.70 mm², P = 0.013), and minimal lumen area (MLA, 3.57 ± 1.52 mm² vs. 4.52 ± 1.40 mm^2, P = 0.042) at the SB ostium between two groups. KUS was positively correlated with the incomplete crush and was the only predictor of in‐stent‐restenosis (ISR) at the SB ostium. Conclusion : DK crush was associated with improved quality of the FKBI and larger MLA. KUS predicted the occurrence of ISR. © 2011 Wiley Periodicals, Inc.     

Proximal Side-Branch Optimization in Crush Stenting: A Step-by-Step Technical Approach in a Silicone Phantom Model

Provisional single drug-eluting stent (DES) strategy remains the standard of care in simple bifurcation lesions which comprise the vast majority of coronary bifurcations. Nevertheless, the presence of complex bifurcations which are defined based on the 1) Side Branch (SB) lesion length of >10 mm and 2) SB ostial diameter stenosis of >70% are approached with a 2-DES strategy upfront. The bifurcation angle will further define the most appropriate technique, with T-stenting more suitable in angulations close to 90°, Culotte and the family of Crush techniques more appropriate for acute angles of <75°. The Crush techniques which are composed of the classic Crush, mini-Crush and double kissing Crush (DK-Crush) share the core principle of protruding the SB DES within the Main Branch (MB) to minimize the risk of ostial SB restenosis, which remains the most prevalent etiology of stent failure during 2-stent approach in bifurcations. Proximal Side Optimization (PSO) is an additional technical consideration to further optimize the protruding SB struts enabling 1) optimal SB strut accommodation to the larger MB vessel diameter, 2) strut enlargement that will further facilitate effortless rewiring for kissing balloon inflation (KBI) avoiding unfavorable guide wire advancement in the peri-ostial SB area.     

Assessment with optical coherence tomography of a new strategy for bifurcational lesion treatment: The Tryton Side‐Branch Stent

The Tryton‐Side Branch Stent? (Tryton Medical, Inc., Newton, MA, USA) is a dedicated stent designed to provide complete carinal coverage of bifurcational lesions. After implantation of a 18 mm cobalt chromium Tryton stent from the left circumflex into the obtuse marginal branch, recrossing with an everolimus eluting Promus stent and final kissing balloon dilatation, optical coherence tomography (OCT) (LightLab Imaging Inc., Westford, MA, USA) was performed with a non‐occlusive technique with motorized pullback (3 mm/s) during continuous pump injection of iso‐osmolar contrast, in both LCx and OM1. OCT imaging showed good strut apposition at the level of the carina, with full coverage and no stent protrusion at the ostium of the side branch. Few malapposed struts were present in the proximal main vessel in the segment of stent superimposition, with a maximal separation from to the vessel wall of 160 μm. The implantation of the Tryton‐Side Branch Stent? allowed full coverage of the side branch ostium with uniform apposition of the stent struts at the level of the carina assessed by OCT. © 2008 Wiley‐Liss, Inc.