Theoretical prediction of side branch compromise after main branch stenting in coronary bifurcation

One of the main problems of treatment of bifurcation lesions is side branch (SB) stenosis appearing after stent placement in the main vessel.The aim of this study was to create quantitative method for prediction of side branch compromise extent.We accepted that the main mechanism for SB ostial stenosis is flow divider (FD) displacement from stent struts after stent implantation in the main vessel.Using easily measurable parameters from coronary angiography,as SB diameter,angle α (initial angle between axes of parent vessel and SB axis) and angle α' (angle between above mentioned axes after stent placement) we can calculate percentage diameter stenosis at branch ostium (%DS):%DS = sin (α - α')/(tan α).In boundary condition of full FD displacement %DS = cos α.We tested our theoretical predictions with fluoroscopic observation of elastic wall model of bifurcation (45°distal angle between branches)permitting wall deformations with stent.There is full coincidence of values of %DS and percentage area stenosis (%AS).The regular formulas for calculations of %DS and %AS overestimate stenosis severity between 10% and 25%.Our model tests have shown full coincidence between predicted values for %DS and observed values.We demonstrate that part of the SB ostium is not visible in regular angiography and contributes to ostial lumen area.This is a method that permits quantitative prediction of side branch compromise.     

Effects of stent design on side branch occlusion after coronary stent placement.

This study was performed to assess the immediate and long-term patency of stent-associated side branches (SB) according to the types of stent. A total of 314 patients with 332 lesions (CrossFlex stent 86, NIR 100, GFX 146) had 365 SB (>1 mm) covered by coronary stents. Side branch occlusion (SBO) occurred in 7.7% of CrossFlex stent, in 10.5% of NIR stent and in 8.8% of GFX stent (P = NS). SBO primarily occurred in SB with ostial disease, and the presence of SB ostial disease was the only independent predictors of SBO after stenting (OR 22.1, 95% CI 9.47-51.49, P < 0.001). At 6 months follow-up, 11 of 31 SBO regained the patency, but the remaining SB had persistent SBO. Delayed SBO occurred in 8 SB, being associated with the presence of SB ostial disease and in-stent restenosis. In conclusions, SBO was not associated with the types of stent design, but with the SB lesion morphology.     

Percutaneous coronary intervention for major bifurcation lesions using the simple approach: risk of myocardial infarction

Background Recent data has suggested that simple (main vessel only) stenting is the preferred approach for patients with bifurcation lesions. We sought to determine the feasibility and outcomes of this approach in a year long inclusive registry. Methods From August, 2004–2005, a registry of 1,600 consecutive patients undergoing PCI was reviewed. Patients undergoing PCI for major bifurcation lesions––≥70% stenosis in a major (≥2 mm) side branch and/or main vessel––were identified by review of the angiograms. Angiographic, clinical and treatment predictors of final SB compromise (≥70% stenosis and/or less than TIMI 3 final flow) were identified. Results Hundred and fifty eight patients who underwent initial stenting of the main vessel with subsequent rescue of the side branch if SB compromise occurred (“Provisional Main Vessel Stenting”) comprised the analysis population. Permanent SB compromise occurred in 16% of patients and was associated with an increased risk of large periprocedural MI and renal failure. Independent predictors of permanent SB compromise were lack of pre-PCI beta blockers, presence of diabetes mellitus, main vessel eccentric lesion and small SB vessel diameter. Conclusion Among unselected patients with major bifurcation lesions undergoing a “simple” stenting approach, there is a significant rate of large periprocedural infarction and side branch compromise.     

Very delayed coronary stent fracture: A case report

A stent fracture is an emerging complication of the coronary stents. There are numerous risk factors for stent fractures; which include forceful exaggerated motion in the atrioventricular groove seen in right coronary artery, long stent, an ostial lesion at the point of maximum curvature in a tortuous vessel, stent over-expansion, stent overlapping with different size stents, complex lesion after stenting of a totally occluded vessel, Cypher stent and a highly mobile segment causing high mechanical stress. Furthermore, chronic stretch at specific vessel sites as bends may lead to late occurrence of fracture.Here we report a case of 40-year-old male who had two overlapping Cypher stents (3.0 × 13 mm and 2.75 × 18 mm) deployed at mid left anterior descending artery 2 years earlier presented with progressive chest pain.     

Extension Distance Mismatch—An Unrecognized Factor for Suboptimal Side Branch Ostial Coverage in Bifurcation Lesion Stenting

Background: The unsatisfactory side branch (SB) ostial strut coverage remains a problem in coronary bifurcation stenting. Both the surplus and lack of struts at SB ostium may be the causative mechanism. We propose that the inability of available stents to cover the “extension distance” of the bifurcation region is the cause of in‐stent restenosis. Methods: The extension distance (ED) is defined as the maximal distance at the carina tip, which must be covered by the stent struts to ensure optimal coverage of the main branch (MB) and SB openings. A mathematical model was created, representing the key factors that govern geometrical reconfigurations after stent implantation in bifurcations. There are two options—with and without bifurcation region deformation. The theoretical assumptions were tested on a bifurcation model (soft polyvinylchloride polymer tubes) permitting free wall deformations and the following parameters: Parent Vessel, MB, SB diameters of 3.5, 3.0, and 2.5 mm, respectively, with an angle of 45° between the MB and SB. After stenting, final KBI with 3.5 mm and 3.0 mm balloons was performed up to 20 atm. Results: After the carina displacement, the ED, which has to be covered, is considerably smaller if the suboptimal result (DS >50%) at the SB ostium is acceptable. The maximal EDs from the bench test measurements are: Vision, Abbott Vascular – 5.62 mm ± 0.04; Liberte, Boston Scientific Corp. – 5.2 mm ± 0.03; Chopin2, Balton – 4.58 mm ± 0.05; Volo, Invatec – 4.41 mm ± 0.04; Driver, Medtronics – 4.39 mm ± 0.04; BxSonic, Cordis, J&J – 4.48 mm ± 0.05. The theoretical maximal ED of the model is 6.91 mm—28–62% larger than actually observed with different stents. Conclusions: The achievement of perfect ostial coverage of the SB is unsatisfactory with most of the currently available stents, especially when poststenting excessive dilation of the ostium of the SB is performed. (J Interven Cardiol 2010;23:305–318)     

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.     

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.     

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.     

Long-term outcome of simultaneous kissing stenting technique with sirolimus-eluting stent for large bifurcation coronary lesions.

OBJECTIVES: This study was conducted to evaluate the outcomes of simultaneous kissing stenting with sirolimus-eluting stent (SES). BACKGROUND: Percutaneous intervention for bifurcation coronary lesions is still challenging. METHODS: This study was designed to evaluate the long-term outcomes of 36 consecutive patients with large bifurcation coronary lesions who underwent simultaneous kissing stenting with SES. RESULTS: Lesion location was unprotected left main in 29 patients (81%) and anterior descending artery in 7 (19%). The patients received a combination of aspirin and clopidogrel for 6 months and cilostazol for 1 month. Mean proximal reference diameter was 4.05 +/- 0.68 mm. Compared with the side branch (SB), the main vessel (MV) involved longer lesions (25.8 +/- 17.0 mm vs. 10.2 +/- 10.8 mm, P < 0.001) and smaller preprocedural minimal lumen diameters (1.02 +/- 0.53 mm vs. 1.46 +/- 0.78 mm, P = 0.006) and was treated with larger stents (3.1 +/- 0.3 mm vs. 3.0 +/- 0.3 mm, P = 0.006). Angiographic success rate was 100%. Over the follow-up of 26.7 +/- 8.6 months, no deaths, myocardial infarctions or stent thromboses occurred. Target lesion revascularization was performed in five patients (14%). Overall angiographic restenosis occurred in 5/30 patients (17%), consisting of 4 (13%) at MV and 3 (10%) at SB. At follow-up angiography, a membranous diaphragm at the carina was identified in 14 patients (47%), but only one of whom was associated with angiographic restenosis. CONCLUSION: Simultaneous kissing stenting with SES appears a feasible stenting technique in large bifurcation coronary lesions. However, a new angiographic structure of carinal membrane developed in a half of patients at follow-up and its influence needs to be further investigated.     

Effectiveness of the stent pull-back technique for nonaorto ostial coronary narrowings

Coronary stenting of nonaorto ostial coronary lesions is challenging because of plaque shift into the main vessel, triggering the use of additional stents. Furthermore, inappropriate coverage of the ostium of the side branch increases the risk of restenosis and target vessel revascularization (TVR). To improve the treatment of nonaorto ostial coronary lesions with a novel interventional technique, we tested the hypothesis that inflating a balloon in the main vessel before stenting the side branch (stent pull-back technique) will limit plaque shifting and reduce the use of additional stents. In addition, proper coverage of the side branch ostium may also reduce 8-month TVR. A case-control design with 100 consecutive patients who underwent drug-eluting stent placement was performed; 55 patients were treated with the stent pull-back technique and 45 patients with a conventional stent technique. Procedural success was 100% for the 2 techniques. The use of additional stents was reduced in the stent pull-back group compared with the conventional stent group (2% vs 18%, p = 0.007). A tendency toward lower ostial miss was also observed in the stent pull-back group (4% vs 13%, p = 0.11). The incidence of in-hospital and 30-day cardiac events was similar between the 2 groups. TVR was lower in the stent pull-back group compared with the conventional group (5% vs 20%; p = 0.03). In conclusion, the stent pull-back technique improves the percutaneous treatment of nonaorto ostial coronary lesions. The technique is associated with a lower use of additional stents and improved clinical outcome, reducing TVR at 8 months of follow-up.     

Simple and complex stent strategies for bifurcated coronary arterial stenosis involving the side branch origin

Coronary lesions located in major bifurcations constitute a challenge for the use of stents. Although the occlusion of a side branch covered by a stent is infrequent, the maintenance of a patent, stenosis-free bifurcation may result in a complex procedure. Between September 1994 and April 1998, 70 patients were treated by stent implantation for coronary bifurcation stenosis. The side branch always had a diameter >2 mm. The pairs of treated arteries were: left anterior descending (LAD)/diagonal artery in 32 patients, circumflex/obtuse marginal in 26, right coronary/posterior descending artery in 5, and LAD/circumflex in 7. We applied 2 different techniques of stent implantation: (1) deployment of 1 stent in the parent vessel covering the takeoff of the side branch and subsequent angioplasty of the side branch across the metallic structure (group A, n = 47 patients), and (2) implantation of 1 stent at the ostium of the side branch and complete reconstruction of the entire bifurcation with additional implantation of 1 or 2 stents at the parent vessel (group B, n = 23 patients). There were no significant differences between groups at baseline variables. Procedural success was similar in both groups: 42 (89%) in group A versus 21 (91%) in group B. However, major cardiac events at 18 months follow-up were higher in group B (event-free probability 44% vs 75%, p <0.05). Selected patients with coronary stenosis at major bifurcations can be treated with an acceptable rate of primary and late success. Complex techniques providing radical stent reconstruction of the bifurcation seems to provide no advantages over the simpler stent jail followed by ostial side branch balloon dilation.     

The glider balloon: A useful device for the treatment of bifurcation lesions

Background

Final kissing balloon dilatation (FKBD) is a recommended final step in case of treatment of bifurcation lesions by two stents approaches. Furthermore, dilatation of the side branch (SB) may be necessary following main vessel (MV) stenting. Occasionally, recrossing the stent struts with a balloon is hampered because the tip hits a stent strut.

Methods

The Glider (TriReme Medical, Pleasanton, CA) is a dedicated balloon designed for crossing through struts of deployed stents toward a SB. From October 2010 to January 2012, FKBD was attempted in 236 consecutive bifurcation lesions treated in our Institution. FKBD was successfully performed by conventional balloon catheters in 221 (93.5%) lesions (Conventional group). In the remaining 15 (6.5%) lesions, where a conventional balloon failed to cross the stent strut, the Glider balloon was attempted (Glider group).

Results

The angle beta (between the axis of the MV after the branch point and the SB axis at the point of divergence) was wider in the Glider group (83 ± 17° versus 65 ± 27°; p = 0.032). A trend toward an higher rate of the true bifurcation lesions was observed in the Glider group (93% versus 70.5%; p = 0.07). The Glider balloon successfully crossed through MV stent struts toward a SB in 12 patients (80%), whereas failed in the remaining 3 patients.

Conclusions

The Glider balloon represents an unique bail-out device which offers an effective rescue strategy for recrossing stent struts during complex bifurcation stenting.     

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.     

Simultaneous stent implantation to treat bifurcation stenoses in the pulmonary arteries: Initial results and long‐term follow up

Background : Balloon angioplasty of bifurcating pulmonary artery (PA) stenoses is often inadequate, and stent treatment often requires simultaneous implantation of two stents. This study evaluates initial results and long‐term follow up of transcatheter stent placement in bifurcating PAs. Methods : This is a retrospective review of patients (pts) who had bifurcating PA stents placed in main and lobar branches from 1993 to 2007. Results : Forty‐nine pts had bifurcating PA stents placed at a median age of 10.9 years (range 1–43 years). The mean minimum vessel diameter increased from 5.7 ± 2.5 mm to 11.0 ± 3.6 mm (P < 0.001), the mean gradient across the stenoses decreased from 37.0 ± 26.9 to 9.2 ± 13 mm Hg (P < 0.001), whereas the mean RV:FA ratio decreased from 0.76 ± 0.29 to 0.53 ± 0.24 (P < 0.001). There was one death due to severe pulmonary hemorrhage. F/U data were available in 38 pts (mean duration 6.3 ± 4.1 years, range 1.2–13.1 years). Thirty pts underwent repeat catheterizations (mean 2.3 ± 2.2 years poststent), with 26 requiring further interventions: Fifteen had balloon angioplasty alone and 11 had additional stents placed. There were no complications at f/u catheterization. Six pts underwent further palliative surgeries, although none for repair of branch PA stenoses. Conclusions : Simultaneous transcatheter placement of bifurcating PA stents provides immediate gradient relief of bifurcating stenoses in the proximal or lobar branch PAs and reduces RV systolic pressure. Further interventions can be safely performed in future procedures, and the presence of stents does not complicate future surgeries. © 2009 Wiley‐Liss, Inc.     

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.     

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.     

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.     

Six-month intravascular ultrasound follow-up of coronary bifurcation lesions treated with rapamycin-eluting stents: technical considerations

INTRODUCTION AND OBJECTIVES: In vitro studies show that stents deform when dilated laterally to access a side branch. This phenomenon may be avoided by use of a kissing balloon at the end of the procedure. However, to date, no in vivo data are available. Our objectives were to investigate the main vessel stent using intravascular ultrasound (IVUS) at six-month follow-up in 55 patients with bifurcation lesions treated using rapamycin-eluting stents and to examine the effect of technical factors. PATIENTS AND METHOD: All patients were treated using provisional or T stents. At 6 months, IVUS measurements were made in the main vessel at both proximal and distal ends of the stent, in reference segments, immediately below the side branch ostium, and at the points where the lumen was smallest and where stent expansion was greatest. RESULTS: The lumen area immediately below the side branch ostium was significantly smaller than that at the point of maximum stent expansion (6.7 [1.8] vs 5.1 [1.3] mm2; P<.05). Underexpansion was not influenced by use of a kissing balloon (stent area immediately under the side branch ostium: 5.5 [0.9] vs 5.6 [1.6] mm2; P=NS) and only one patient experienced restenosis at this point. The lumen areas at the proximal and distal edges of the stent were almost identical in patients who did or did not undergo balloon dilation beyond the ends of the stent. CONCLUSIONS: Stent underexpansion below the side branch ostium was frequently found following provisional or T stenting of bifurcation lesions. This minor stent deformity was not prevented by use of a kissing balloon nor by any specific side branch treatment and had no significant impact on the restenosis rate.     

Treatment of bifurcation coronary lesions: a review of current techniques and outcome

Percutaneous treatment of coronary bifurcation lesions, pose a number of technical challenges to the interventional cardiologist. Each lesion has to be approached with its own, targeted solution in the context of the clinical picture, anatomy, and pathology. To achieve acceptable clinical outcomes a number of established techniques are available. The exact anatomy of the lesion determines the technique used. The most common approach is to stent the main vessel across the ostium of the side branch. The side branch can be additionally treated with a second stent or balloon angioplasty depending on the severity of the ostial lesion and/or evidence of active ischemia. Other techniques involve stenting the main branch up to the carina but sparing the side branches, multiple 'kissing stent' approaches ('Y','T', and 'V') or the 'culottes' technique. Follow-up data demonstrates a high (over 90%) technical success rate. Clinical outcome is variable but with conventional stents restenosis rates higher than 30% have been reported in most studies and there is no added advantage in routine stenting of both main vessel and side branch. Recent introduction of drug-eluting stents has resulted in a lower event rate and reduction of main vessel restenosis in comparison with historical controls. Side branch ostial restenosis remains a problem, which may require the development of novel 'bifurcate' stent designs to allow complete coverage with a single stent.