Coronary bifurcation lesions

Treatment of coronary bifurcation lesions represents a challenging area in interventional cardiology, but recent advances in percutaneous coronary interventions have led to a dramatic increase in the number of patients successfully treated percutaneously. When compared with nonbifurcation interventions, bifurcation interventions have a lower rate of procedural success, higher procedural costs, longer hospitalization, and a higher rate of clinical and angiographic restenosis. The recent introduction of drug-eluting stents has resulted in a lower event rate and reduction of main vessel restenosis compared with historical controls. Side branch ostial residual stenosis and long-term restenosis remain a problem, however. Although stenting the main vessel with provisional side branch stenting seems to be the prevailing approach, in the era of drug-eluting stents, various two stent techniques have emerged to allow stenting of the large side branch also.     

Practical Clinical Evaluation of Stents

This article discusses the clinical issues pertaining to an optimal stenting result and analyzes relevant stent structures and functions. There are five components of optimal stenting: favorable clinical features, easy stent delivery, ideal scaffolding, low stent thrombosis, and low restenosis. In straightforward cases, such as stenting in the mid-right coronary artery with a straight proximal segment, procedural success can be achieved with any stent. In vessels with curved, tortuous proximal segments, a highly flexible stent is needed for a smooth and successful delivery. For ostial, protected left main, or aortoanastomotic lesions, stents with sufficient radial strength and good visibility are needed. The two major concerns of an interventional cardiologist choosing a stent are excellent trackability for fast delivery and low long-term restenosis rate. In all situations, the procedural success depends on the operator's manual dexterity, experience with a particular stent design, and critical evaluation of different structural stent features to maximize benefits. Any new stent with high longitudinal flexibility, excellent scaffolding and radial strength, adequate radiopacity, complete deployment after one inflation, and that is easily recrossed and provides a good symmetrical conduit for a smooth coronary flow resulting in little tendency for thrombosis or restenosis would be today's stent of choice.     

Modified T-stenting technique with crushing for bifurcation lesions: immediate results and 30-day outcome.

We report a new stenting technique employed in 20 consecutive patients to treat true bifurcation lesions using the Cypher stent (Cordis, Warren, NJ). Both stents are advanced at the site of the bifurcation. The proximal marker of the side-branch stent must be situated in the main branch at a distance of 4-5 mm proximal to the carina of the bifurcation and the main branch stent must cover the bifurcation as well as the protruding segment of the side-branch stent. The side-branch stent is deployed first and balloon and wire are removed. The stent deployed in the main branch completely covers and crushes the protruding segment of the side branch stent against the vessel wall of the main branch. Following main- and side-branch predilatation, stents were successfully deployed in all lesions. Final kissing balloon inflation was performed in seven patients. Two patients had in-hospital myocardial infarction and one patient underwent in-hospital re-PTCA due to a dissection distal to a stent. No other major adverse cardiac events were observed in-hospital and during 1-month clinical follow-up. Treatment of bifurcation lesions using crushing stent technique is feasible with acceptable rate of procedural complications. Angiographic follow-up is necessary to prove the advantage of this specific technique to give complete coverage of the ostium of the side branch with a drug-eluting stent.     

Coronary bifurcation lesions: to stent one branch or both?

OBJECTIVE: The purpose of this study was to evaluate two different stent placement techniques for bifurcation lesions: 1) stenting of the main branch and balloon dilatation of the sidebranch versus 2) stenting of both branches. BACKGROUND: Percutaneous coronary intervention (PCI) of coronary bifurcation lesions remains challenging, and limited information is available regarding whether stent placement is necessary in both branches of the bifurcation using bare-metal stents. Methods. We prospectively followed all patients who underwent PCI for symptomatic bifurcation lesions at our center. All patients were carefully followed for subsequent clinical events. RESULTS: Between March 2001 and November 2002, a total of 50 patients were treated with either stenting of both vessels (double stent group; n = 32) or stenting of the parent vessel and balloon angioplasty of the sidebranch (single stent group; n = 18). Optimal angiographic success was 87.5% in the single stent group and 100% in the double stent group (p = 0.1). The post-procedure percent diameter stenosis of the sidebranch vessel was significantly higher in the single stent group (18 +/- 25% versus 4 +/- 8%; p = 0.005). At 6 months, the incidence of clinically driven repeat target lesion revascularization was 37.6% with 2 stents as compared to 5.6% using 1 stent (p = 0.01). Angiographic restenosis was documented in 40.6% using 2 bifurcation stents, as compared to 11% when using 1 stent (p = 0.05). By multivariable analysis adjusted for baseline differences, stenting the sidebranch was a borderline predictor for major adverse cardiac events at 6 months (odds ratio = 10.3; 95% confidence interval, 0.9-116; p = 0.053). CONCLUSION: For the treatment of true bifurcation lesions, a strategy of stenting both vessels using bare metal stents seems to be associated with worse long-term results, as compared to stenting only the parent vessel.     

Present status of coronary bifurcation stenting

Percutaneous coronary intervention (PCI) for bifurcation lesions is technically limited by the risk of side branch occlusion. In comparison with nonbifurcation interventions, bifurcation interventions have a lower rate of procedural success, higher procedural costs and a higher rate of clinical and angiographic restenosis. The recent introduction of drug-eluting stents (DES) has resulted in reduced incidence of main vessel restenosis compared with historical controls. However, side-branch ostial residual stenosis and long-term restenosis still remain problematic. In the era of DES, techniques employing two stents have emerged that allow stenting of the large side branch in addition to the main artery. Stenting of the main vessel with provisional side branch stenting seems to be the prevailing approach. This paper reviews outcome data with different treatment modalities for this complex lesion with particular emphasis on the use of DES as well as potential new therapeutic approaches.     

Coronary bifurcation stenting using dedicated bifurcation stents.

We report three cases of successful implantation of three different stents specially designed for bifurcation lesions, guided by intracoronary ultrasound. The BARD and AVE are true bifurcated stents for side-branch access and the NIR-Side Royal is a single modified NIR stent with an aperture to allow provisional bifurcation stenting. These designs introduce a new era in percutaneous management of coronary bifurcation lesions. Cathet. Cardiovasc. Intervent. 49:105-111, 2000.     

Stenting of bifurcation lesions: a rational approach

The occurrence of stenosis in or next to coronary bifurcations is relatively frequent and generally underestimated. In our experience, such lesions account for 15%-18% of all percutaneous coronary intervention > (PCI). The main reasons for this are (1) the coronary arteries are like the branches of a tree with many ramifications and (2) because of axial plaque redistribution, especially after stent implantation, PCI of lesions located next to a coronary bifurcation almost inevitably cause plaque shifting in the side branches. PCI treatment of coronary bifurcation lesions remains challenging. Balloon dilatation treatment used to be associated with less than satisfactory immediate results, a high complication rate, and an unacceptable restenosis rate. The kissing balloon technique resulted in improved, though suboptimal, outcomes. Several approaches were then suggested, like rotative or directional atherectomy, but these techniques did not translate into significantly enhanced results. With the advent of second generation stents, in 1996, the authors decided to set up an observational study on coronary bifurcation stenting combined with a bench test of the various stents available. Over the last 5 years, techniques, strategies, and stent design have improved. As a result, the authors have been able to define a rational approach to coronary bifurcation stenting. This bench study analyzed the behavior of stents and allowed stents to be discarded that are not compatible with the treatment of coronary bifurcations. Most importantly, this study revealed that stent deformation due to the opening of a strut is a constant phenomenon that must be corrected by kissing balloon inflation. Moreover, it was observed that the opening of a stent strut into a side branch could permit the stenting, at least partly, of the side branch ostium. This resulted in the provocative concept of "stenting both branches with a single stent." Therefore, a simple approach is currently implemented in the majority of cases: stenting of the main branch with provisional stenting of the side branch. The technique consists of inserting a guidewire in each coronary branch. A stent is then positioned in the main branch with a wire being "jailed" in the side branch. The wires are then exchanged, starting with the main branch wire that is passed through the stent struts into the side branch. After opening the stent struts in the side branch, kissing balloon inflation is performed. A second stent is deployed in the side branch in the presence of suboptimal results only. Over the last 2 years, this technique has been associated with a 98% angiographic success rate in both branches. Two stents are used in 30%-35% of cases and final kissing balloon inflation is performed in > 95% of cases. The in-hospital major adverse cardiac events (MACE) rate is around 5% and 7-month target vessel revascularization (TVR) is 13%. Several stents specifically designed for coronary bifurcation lesions are currently being investigated. The objective is to simplify the approach for all users. In the near future, the use of drug-eluting stents should reduce the risk of restenosis.     

Progress in percutaneous management of coronary bifurcation lesions

Bifurcation lesions have been recognized as one of the most important challenges facing the interventional cardiologist since the beginnings of percutaneous coronary intervention (PCI). The potential of periprocedural occlusion of the side branch was discovered to be significant, leading to early attempts at protecting the side branch with a second guide wire and kissing balloon inflation in order to minimize this risk and thus improve the procedural and short-term success of the procedure. The advent of stenting significantly improved the safety of the procedure, although, side branch success continued to be a challenge. A variety of single as well as double stenting techniques were developed that improved the safety and short-term results of percutaneous coronary intervention involving side branches. Long-term success, however, continued to elude, due to an increased need for target lesion revascularization (TLR) and higher major adverse cardiac event (MACE) rates following PCI of bifurcation lesions. Of the techniques, main vessel stenting and balloon inflation of the side branch, T-stenting, and permutations of Y-stenting including the Culotte, emerged. The introduction of drug-eluting stents appears to have brought bifurcation PCI to a new level of long-term efficacy. Specialty bifurcation stents have been developed to provide easy access to the side branch, however, these have to date had little impact on practice and have not been adopted widely. New techniques such as crush stenting and its several permutations, and simultaneous kissing stenting developed specifically for drug-eluting stents have been developed. Debate continues as to which is the most efficacious technique. True randomized comparisons are, however, lacking. It is likely that all of the currently utilized techniques have a place in the interventional cardiologist's quiver and that each is appropriate in a particular anatomical scenario. Nonetheless, well-designed randomized trials evaluating the various bifurcation techniques especially in complex bifurcation lesions are needed.     

A prospective registry to evaluate sirolimus-eluting stents implanted at coronary bifurcation lesions using the "crush technique"

The "crush technique" has been proposed as an alternative approach to treat bifurcation lesions because of its predictability and high procedural success rate. However, few data are available regarding its safety and long-term efficacy. We report the long-term clinical outcomes of patients with coronary bifurcation lesions treated with sirolimus-eluting stents using the crush technique. From April 2003 to May 2004, 120 patients with coronary bifurcation lesions were treated with sirolimus-eluting stents using the crush technique. Six months of clinical follow-up was completed in 95.8% of patients. Mean patient age was 64 years; 36% had diabetes mellitus, and the left anterior descending artery/diagonal was the most frequent bifurcation location (69%). Final kissing balloon inflation was performed in 87.5% of patients. Compared with the main vessel, side branch lesions were shorter, with a smaller reference diameter and final in-stent minimum lumen diameter. Procedural success was achieved in 97.5%. At 30 days of follow-up, 1 patient had died of noncardiac causes and 2 patients (1.7%) had subacute stent thrombosis. At 6 months of follow-up, target lesion revascularization was required in 13 patients (11.3%), all of whom had focal restenosis predominantly at the side branch ostium. In conclusion, the crush technique with final kissing balloon inflation can be safely used by experienced operators to treat highly complex bifurcation lesions with sirolimus-eluting stents. The safety profile of this technique is similar to that of other bifurcation stenting techniques reported thus far. Nonetheless, despite the excellent patency rates of the main vessel, the need for revascularization at the ostium of the side branch was not fully eliminated.     

Coronary bifurcation stenting. Current techniques, outcome and possible future developments

Percutaneous treatment of coronary bifurcation lesions remained challenging in the stent era, with restenosis rates greater than 30% and no advantage from the routine use of kissing stents. Drug eluting stents (DES) have dramatically reduced the restenosis rates (RR) in the main vessel, but with conventional T-stenting double digits figures are still reported for the side-branch because of poor ostial coverage. The techniques of kissing stenting able to provide full lesion coverage (Culotte, V-stenting, Crush) have the potential to improve these results but the development of dedicated DES is probably needed to obtain consistently high procedural and long-term success.     

血管内超声在分叉病变介入中的价值

即使在药物支架时代和采用多种术式,如Crush技术、Culotte支架术和V支架术等,无论手术成功率还是长期主要心血管事件、靶病变重建、再狭窄和支架内血栓方面,分叉病变的介入治疗目前仍充满挑战,目前必要支架术策略为术者广泛接受,但是对于分支血管严重狭窄的患者,双支架术仍然必需。血管内超声可以精确提供血管和管腔的大小、粥样斑块空间定位和几何学特征,所以血管内超声在术前评估斑块负荷、指导经皮冠状动脉介入治疗和随访期间理解支架失败具有重要作用,现综述血管内超声在分叉病变介入治疗中的价值。     

Very late stent thrombosis complicating a previously lost and partially crushed stent: Demonstration by optical coherence tomography

Stent thrombosis (ST) is the most dramatic complication of coronary stenting. Mechanisms of ST are multiple, including procedural and patient-related factors. A considerable burden of metal inside the coronary has been associated with ST as suggested by the higher rate of ST in case of multiple overlapping or complex two stents procedure in bifurcation lesions. However, occasional stent loss and failure to retrieve it may be a substrate of ST, especially if multiple layers of stent struts are incompletely crushed. Here, we describe a case of very late ST on a partially crushed stent previously lost inside the coronary circulation, using optical coherence tomography (OCT) for guidance during the procedure.     

A stepwise strategy for the stent treatment of bifurcated coronary lesions.

Several observational studies have shown a better late outcome in patients with coronary bifurcation lesions treated with stents in whom the side branch was not stented. Balloon dilation and provisional stenting for the side branch seem an attractive strategy to manage these challenging types of lesions. This study evaluated the results of a three-step phase strategy in the stent treatment of bifurcated coronary lesions. We treated 126 patients, 58 +/- 11 years old, with major coronary bifurcation stenosis. The therapeutic procedure was undertaken following three phases; progression through each phase was triggered by the failure of one procedure to achieve a <50% residual stenosis at the side branch: in the first step, balloon angioplasty of the side branch followed by stenting of the parent vessel; in the second, balloon redilation of the side-branch origin across the metallic structure of the stent; in the third, stenting of the side-branch origin. Immediate success was achieved in 116 patients (92%). Angiographic results in each phase were as follows: in the first step, 35 patients (28%) had procedural success, 3 patients had failure, and 88 crossed to the next step; in the second, 76 patients (86%) had procedural success, 7 patients had failure, and 5 crossed to the next step; in the third, all 5 patients had procedural success. The overall major cardiac event-free probability at 15 months was 78%. Target vessel revascularization took place in 19 patients (15%) and when stratified by phases were 13% of patients treated in the first step, 16% of patients in the second step, and 20% of patients in the third step. Patients with coronary stenosis at major bifurcations may be treated following an unitary stepwise approach. This attitude may avoid side-branch stent implantation in most patients, providing good immediate and long-term results.     

Technical feasibility,safety, and clinical outcome of stenting of unprotected left main coronary artery bifurcation narrowing

This study was performed to evaluate the acute and long-term results of stenting for unprotected left main coronary artery (LMCA) bifurcation lesions. Sixty-three consecutive patients with an unprotected LMCA bifurcation lesion and normal left ventricular function were included. Stenting was performed with (n = 32) or without debulking atherectomy (n = 31) at the operator's discretion. Slotted-tube stents, coil stents, or bifurcation stents were used. The procedural success rate was 100%. In-hospital events including stent thrombosis, Q-wave myocardial infarction, and emergency bypass surgery did not occur in any patients. The angiographic follow-up rate was 86% (43 of the 50 eligible patients), and the restenosis rate was 28% (parent vessel only 14%, side branch only 9%, and both 5%). Restenosis at the parent vessel occurred less frequently in the debulking group than in the nondebulking group (5% vs 33%, respectively, p = 0.02). In multivariate analysis, the debulking procedure was an independent predictive factor of restenosis for the parent vessel (odds ratio 0.10, 95% confidence intervals 0.01 to 0.91, p = 0.04). Clinical follow-up was obtained in all patients at 19.9 +/- 13.7 months. There were 2 deaths (noncardiac origin), but no myocardial infarction during follow-up. Target lesion revascularization was required in 6 patients. The event-free survival rate (death, nonfatal myocardial infarction, and repeat revascularization) was 86% at the end of the follow-up period. In conclusion, stenting for an unprotected LMCA bifurcation lesion may be performed with a high procedural success rate and a favorable clinical outcome in selected patients with normal left ventricular function, suggesting that stenting would be an effective alternative to surgery in these patients.     

Fork in the road: Are all bifurcations created equal?

• The TRYTON study evaluated routine side branch (SB) stenting with a novel bare metal stent (BMS) designed for true bifurcation lesions (Medina 1,1,1; 1,0,1; 0,1,1) and compared it to a strategy of balloon angioplasty with provisional stenting. It failed to meet the primary endpoint of non‐inferiority in target vessel failure mainly driven by peri‐procedural myocardial infarction (MI) with elevated CK‐MB > 3× the upper limit of normal.
• In this substudy, 41% of patients who had a SB diameter > 2.25 mm were evaluated and the new stent was found to be non‐inferior in the primary outcome of target vessel failure with no difference in post‐procedural MI.
• This substudy suggests that appropriately sized SB stents with TRYTON may be useful when the SB is >2.25 mm in diameter. However, further studies could evaluate routine use of FFR for SBs; drug eluting versions of the stent as well as stents designed for vessels 2.25 mm in diameter which are frequently felt to be clinically larger when not subjected to core lab analysis.

     

Drug eluting stenting in bifurcation coronary lesions long-term results applying a systematic treatment strategy

Objectives : To explore the long‐term results following implantation of drug‐eluting stents (DES) in bifurcation lesions according to contemporary “real world” practice. Background : Limited information is available on the long‐term outcomes of patients with bifurcation lesions who are treated using DES. A systematic approach for bifurcation lesion management was applied, using either a “provisional” single stent technique or a dedicated two stents strategy according to the side‐branch diameter and severity of its ostial stenosis. Methods : Four hundred one consecutive patients underwent bifurcation percutaneous coronary intervention (PCI) using DES and were included in our prospective registry. All adverse events were recorded up to 2 years and distinguished according to the planned PCI strategy (e.g., one versus two stents technique). Results : A planned two stents strategy was used in 141 patients (35% of patients). In 260 patients (65%), the planned treatment involved stenting of the main branch only with “provisional” stenting of the side‐branch according to procedural course. Thus, 24 patients (9.2%) needed additional stenting at the side‐branch to complete the PCI. Cumulative major adverse cardiac event rate at 1 and 2 years was similar for both groups (11.4% vs. 14.8% at 1 year and 19.4% vs. 25.7% at 2 years for the single vs. two stents groups, accordingly, P = NS for both). Likewise, there was no difference in mortality, cardiac mortality, myocardial infarction, need for target lesions or target vessel revascularization, or definite stent thrombosis rate between the two groups at 6, 12, and 2 years follow‐up. The rate of angiographically confirmed (i.e., definite) stent thrombosis did not differ between the two groups during follow‐up. Conclusions : Our study revealed favorable long‐term clinical results following DES implantation using a systematic, rather simplified approach towards bifurcation stenting and using either a single or double stenting technique. © 2011 Wiley Periodicals, Inc.     

Examination of Stent Deformation and Gap Formation after Complex Stenting of Left Main Coronary Artery Bifurcations Using Microfocus Computed Tomography

Background: Fluoroscopy and intravascular ultrasound (IVUS) lack sufficient resolution for assessing the results of complex stenting in true bifurcation lesions.
Objectives: After diverse bifurcation stenting at the left main coronary artery (LM) bifurcation model, the results were examined using microfocus computed tomography (MFCT).
Methods: The strut distribution of three kinds of stents deployed on a straight vessel segment was investigated. Classical crush, double kissing (DK)–double crush, and culotte stenting were performed on a three-dimensional (3D) LM model. The results were assessed using cross-sectional, longitudinal, and 3D reconstruction views of MFCT.
Results: Nonuniform strut distribution was observed in a corrugated stent design deployed on a straight vessel segment. Following classical crush stenting, a relatively large gap at the nonmyocardial site was observed in the corrugated stents. When the guidewire recrossed outside the ostium of the crushed side branch stent, kissing balloon inflation caused further crushing of the stent at the more distal segment. The dilated strut rose up from the main vessel bed after the first kissing balloon inflation in DK crush stenting; the advantage of DK would be cancelled after main vessel stenting due to recrushing the raised strut. The culotte stenting with closed-cell stents showed the restriction of the expansion at the branch ostium when it was dilated with a 3.5-mm balloon. The culotte stenting with open-cell-based stents showed a good stent apposition except for a tiny gap and small metallic carina at the distal bifurcation.
Conclusion: MFCT analysis in the 3D phantom model is useful to assess the structural deformation of the stents and gap on vessel wall coverage after complex stenting at the LM bifurcation.     

Review of percutaneous therapy for bifurcation lesions in the era of drug-eluting stents

Although recent advances in percutaneous coronary interventions (PCI) have led to dramatic expansions in procedural complexity, bifurcation lesions (BL) remain a serious challenge for the interventionalist. Turbulent flow dynamics and high shear stress likely predispose coronary bifurcations to development of atherosclerotic plaques. These lesions comprise 15% to 20% of the total number of coronary interventions. When compared with non-BL interventions, BL interventions demonstrate lower procedural success rates, higher procedural costs, longer hospitalizations, and higher clinical and angiographic restenosis rates. The recent introduction of drug-eluting stents (DES) has resulted in lower incidences of target lesion/ vessel revascularization and reduction of main branch restenosis in this anatomic subset, when compared to historical bare metal stent (BMS) controls. Nonetheless, DES have not resolved the bifurcation PCI problem; and several techniques employing either 1 or 2 stents have emerged. Stenting of the main vessel with provisional side branch stenting seems to be the prevailing approach. While no definitive single BL-PCI technique has been identified, the optimal approach is likely lesion-specific. This paper reviews different treatment modalities for this complex lesion subset, with particular emphasis on the use of DES, as well as new potential therapeutic approaches.     

Assessment of intermediate severity coronary lesions in the catheterization laboratory.

The management of intermediate coronary lesions, defined by a diameter stenosis of 40% to 70%, continues to be a therapeutic dilemma for cardiologists. The 2-dimensional representation of the arterial lesion provided by angiography is limited in distinguishing intermediate lesions that require stenting from those that simply need appropriate medical therapy. In the era of drug-eluting stents, some might propose that stenting all intermediate coronary lesions is an appropriate solution. However, the possibility of procedural complications such as coronary dissection, no reflow phenomenon, in-stent restenosis, and stent thrombosis requires accurate stratification of patients with intermediate coronary lesions to appropriate therapy. Intravascular ultrasound (IVUS) and fractional flow reserve index (FFR) provide anatomic and functional information that can be used in the catheterization laboratory to designate patients to the most appropriate therapy. The purpose of this review is to discuss the critical information obtained from IVUS and FFR in guiding treatment of patients with intermediate coronary lesions. In addition, the importance of IVUS and FFR in the management of patients with serial stenosis, bifurcation lesions, left main disease, saphenous vein graft disease, and acute coronary syndrome will be discussed.     

Assessment of intermediate severity coronary lesions in the catheterization laboratory

The management of intermediate coronary lesions, defined by a diameter stenosis of 40% to 70%, continues to be a therapeutic dilemma for cardiologists. The 2-dimensional representation of the arterial lesion provided by angiography is limited in distinguishing intermediate lesions that require stenting from those that simply need appropriate medical therapy. In the era of drug-eluting stents, some might propose that stenting all intermediate coronary lesions is an appropriate solution. However, the possibility of procedural complications such as coronary dissection, no reflow phenomenon, in-stent restenosis, and stent thrombosis requires accurate stratification of patients with intermediate coronary lesions to appropriate therapy. Intravascular ultrasound (IVUS) and fractional flow reserve index (FFR) provide anatomic and functional information that can be used in the catheterization laboratory to designate patients to the most appropriate therapy. The purpose of this review is to discuss the critical information obtained from IVUS and FFR in guiding treatment of patients with intermediate coronary lesions. In addition, the importance of IVUS and FFR in the management of patients with serial stenosis, bifurcation lesions, left main disease, saphenous vein graft disease, and acute coronary syndrome will be discussed.