The Frontier stent registry: safety and feasibility of a novel dedicated stent for the treatment of bifurcation coronary artery lesions

OBJECTIVES: The goal of this study was to evaluate the safety and performance of the Multi-Link Frontier coronary bifurcation stent system (Guidant Corp., Santa Clara, California), a novel dedicated device designed for permanent side branch (SB) access, stent delivery by simultaneous kissing balloon inflation, and optimal main branch (MB) and SB ostium scaffolding. BACKGROUND: The treatment of coronary bifurcation lesions remains challenging, and various approaches using stents have been proposed. METHODS: The primary end point was the 180-day incidence of major adverse cardiac events (MACE) per intent-to-treat analysis. Secondary end points included device success, 30-day MACE, angiographic restenosis, and target lesion revascularization (TLR) rates at 180 days. RESULTS: After a learning phase of two cases per center, 105 patients were prospectively included in 11 centers. The left anterior descending coronary artery/diagonal bifurcation was the target in 80% of cases. The Frontier stent was successfully implanted in 96 patients (91%), and procedural success was obtained in 93%. Two patients suffered in-hospital myocardial infarction (MI) secondary to SB occlusion, and one patient underwent elective coronary artery bypass grafting. At 30 days and 6 months, the MACE rates were 2.9% and 17.1% (no death, no subacute stent thrombosis, Q-wave MI 1.0% and 1.9%, non-Q-wave MI 1.0% and 1.9%, TLR 1.0% and 13.3%). The MB in-stent restenosis was 25.3%, in-segment 29.9%. The SB restenosis was 29.1%. The overall restenosis rate for any branch was 44.8%. CONCLUSIONS: The results of this Frontier registry demonstrate the safety and performance of this dedicated stent system for the treatment of bifurcation lesions. The device can be successfully implanted in more than 90% of all cases, with a high procedural success rate and low 30-day and 6-month MACE rates.     

A new dedicated stent and delivery system for the treatment of bifurcation lesions: preliminary experience.

We report the first clinical experience in eight patients with a new stent and delivery system specifically designed for the treatment of bifurcational lesions. The device (AST SLK-View system) consists of a premounted stent and a delivery system. The stent has a side aperture, which orients toward the ostium of the side branch. The system allows deployment of the stent while the access to both main and side branches is maintained by two wires. We evaluated this system in nine bifurcations. The location of bifurcations was left descending artery/diagonal branch in four lesions, left circumflex/obtuse marginal branch in three lesions, and postero-lateral branch/posterior descending artery in two lesions. Predilation was performed in six lesions of the main branches and in five lesions of the side branches. The stent was effectively delivered to all bifurcations except for one, in which the target lesion was located at a distal segment and the device could not be delivered. Following stent implantation in the main branch, two lesions at the side branches were treated by stent, while the other lesions were treated by balloon angioplasty without difficulty. Final kissing balloon was performed in four bifurcation lesions. No adverse event was observed during 1 month of clinical follow-up. Treatment of bifurcation lesions with this new dedicated device appears to be feasible. This new device may introduce a new approach for the treatment of coronary bifurcation lesions.     

Novel stent system for bifurcation lesions: examination by intravascular ultrasound.

Bifurcation disease represents a mechanical and biological challenge for definitive interventional treatment. This case report discusses an experience with a novel stent system designed for the treatment of bifurcation lesions.     

Novel method of coronary stent delivery.

Occasionally a coronary stent cannot be delivered. In this case, a dislodged stent was purposely pushed forward by the delivery balloon into position; a smaller, compliant balloon was used for initial deployment; and the original stent-delivery balloon was used for subsequent final deployment.     

Management of calcified coronary artery bifurcation lesions

Calcified coronary artery bifurcation lesions (CBL) remain a challenge for the interventional cardiologist. Evidence regarding treatment of CBL is minimal. Optimal plaque modification is the most important step prior to stent deployment. Provisional stenting is the preferred strategy for most bifurcation lesions. However, two-stent strategy should be considered for BL with compromised large SB (>2.5 mm) supplying a large territory, >70% SB stenosis and lesions more than 5 mm long. In this contemporary review article, we present a simplified approach to treating CBL and demonstrate the approach to specific case examples using our newly developed mobile application, BifurcAID.     

冠状动脉分叉病变的介入治疗

临床上冠状动脉分叉病变占冠状动脉介入治疗的15%～20%,一直是该治疗领域的难点.进入药物支架时代,新器械的发明和新技术的应用显著降低了急性并发症及中、远期的靶血管重建率、再狭窄率.该文简要介绍分叉病变的介入治疗现状.     

药物涂层球囊在冠状动脉分叉病变边支介入治疗中的临床应用

目的探讨药物涂层球囊应用于冠状动脉分叉病变边支血管保护的可行性分析。方法选择2015年3月~2016年3月在解放军总医院经冠状动脉造影证实冠状动脉分叉病变患者20例,Medina分型1,1,1;1,0,1;0,1,1,分别为11、5、4例。行PCI,于主支血管置入药物洗脱支架,边支血管用药物涂层球囊主动保护技术处理,术后即刻冠状动脉造影检查。术后6个月临床随访,统计患者主要心脑血管不良事件。结果20例患者PCI成功率为100%。20例患者主支置入药物洗脱支架,边支血管用药物涂层球囊主动保护技术处理,主支血管最小管腔直径由术前(1.49±0.46)mm增加至术后(3.20±0.53)mm(P=0.001),分支血管由术前(1.36±0.66)mm增加至术后(1.78±0.61)mm(P=0.048)。术后6个月患者无主要心脑血管不良事件发生。结论药物涂层球囊主动保护技术应用于冠状动脉分叉病变边支血管保护安全、有效。     

Classification and treatment of coronary artery bifurcation lesions: putting the Medina classification to the test

BackgroundCoronary bifurcation lesions are common, difficult to treat, and associated with poorer outcomes compared to non-bifurcation lesions. The Medina classification has been widely adopted as the preferred system to classify bifurcation lesions, however there have been little efforts to characterize this metric. The objective of this study was to characterize the inter-observer variability of the Medina classification and examine its contribution to treatment selection strategy.Methods and materialsWe invited 150 interventional cardiologists from the United States and Europe to complete an online survey evaluating 12 freeze frame coronary angiograms of bifurcation lesions. Each respondent was asked to characterize the bifurcation lesions using the Medina classification and other metrics including side branch vessel size and angle. Respondents were asked to designate either a provisional (1 stent) or dedicated (2 stent) treatment strategy. ‘Complex’ lesions were defined as Medina scores 1.1.1, 0.1.1, or 1.0.1.ResultsA total of 49 interventional cardiologists responded. In 7 of the 12 angiograms evaluated, there was > 75% agreement regarding lesion classification using the Medina system. There was moderate inter-observer agreement when using Medina to classify lesions as ‘Complex’ vs. ‘non-Complex’. ‘Complex’ bifurcation designation and side branch size were predictive of selection of a dedicated treatment strategy, whereas side branch angle was not.ConclusionsThe Medina classification is a useful tool in characterizing coronary bifurcation lesions. For the majority of the angiograms evaluated there was good inter-observer agreement in lesion classification using the Medina system. ‘Complex’ bifurcation designation and side branch size were predictive of selection of a dedicated treatment strategy.     

国产及进口药物涂层支架在冠状动脉分叉病变治疗中的短期疗效比较

目的 评价国产及进口雷帕霉素药物涂层支架在冠状动脉分叉病变中的短期临床疗效.方法 60例冠状动脉分叉病变患者随机分为两组,每组30例,分别置人国产及进口雷帕霉素药物涂层支架(PARTNER和CYPHER).依据分叉病变主支与分支的夹角关系采取不同的双DES置入术,比较两种支架的即刻手术成功率、住院期及6个月随访期内的主要不良事件发生率及6个月后的支架内和病变节段内再狭窄率.结果 两组患者各成功置入60个支架,冠脉造影显示即刻手术成功率均为100%.PARTERN支架组与CYPHER支架组患者住院期不良事件发生率分别为0%(0/30)和3.3%(1/30),两组差异无统计学意义(P>0.05);随访期不良事件发生率分别为21.4%(6/28)和17.2%(5/29),两组差异无统计学意义(P>0.05);支架内再狭窄率分别为10.7%(3/28)和6.9%(2/29).两组差异无统计学意义(P>0.05).结论 国产及进口雷帕霉素药物洗脱支架治疗冠脉分叉病同样安全有效.     

Three‐year outcome of drug‐eluting stent implantation for coronary artery bifurcation lesions

Objectives: To compare the very long‐term clinical outcomes of bifurcation lesions using the crush and the simultaneous kissing stent (SKS) techniques. Background: A variety of two‐stent techniques have been used to treat coronary artery bifurcation lesions in the drug‐eluting stent era, but the long‐term clinical outcome of these approaches is not known. Methods: A total of 74 consecutive patients underwent bifurcation stenting using either the crush or SKS techniques. Mean patient age was 66.91 ± 11.3 years; 26% were diabetic, and the left anterior descending/diagonal bifurcation was the most frequently treated lesion (68%). Results: In‐hospital outcomes were not significantly different between groups. Over a median follow‐up of 3.3 years, 1 patient in the SKS group and 3 patients in the crush group died (P = ns). Probable stent thrombosis leading to death according to the Academic Research Consortium definition occurred in 1 patient in the crush group. Mortality in the remaining 3 patients was noncardiac. Target lesion revascularization (TLR) occurred in 14 patients (40%) in the SKS group and 5 patients (12.8%) in the crush group (P = 0.015). Survival free from major adverse cardiac events (MACE) was significantly less in the SKS group and predominantly driven by TLR (60 vs. 88%, P = 0.001). Conclusions: In conclusion, over a median of 3.3 years of follow‐up, TLR and MACE are significantly lower in bifurcation lesions treated with the crush technique when compared with the SKS technique. Definite or probable stent thrombosis is rare with either technique. © 2009 Wiley‐Liss, Inc.     

A porcine coronary stent model of increased neointima formation in the left anterior descending coronary artery

BACKGROUND: Clinical trials suggest an increased frequency of restenosis after coronary intervention in left anterior descending (LAD) compared to the left circumflex or right coronary arteries. Experimental studies correlate stent-induced arterial injury and the extent of neointima formation. This study investigates whether the coronary artery affects the relationship between arterial injury and neointima hyperplasia in the porcine stent model. METHODS: Non-lipemic farm pigs underwent stent placement in the LAD (n = 26) and the right coronary artery (RCA; n = 30). Quantitative coronary angiography (QCA) was performed before and after stent placement, and at follow-up; quantitative histomorphometry and injury score were analyzed at 30-day follow-up. RESULTS: Initial procedure balloon/artery ratios (LAD 1.17 +/- 0.11 vs RCA 1.17 +/- 0.09, P = NS), and minimal stent lumen diameters (MLD; LAD 2.91 +/- 0.31 vs RCA: 2.93 +/- 0.28 mm, P = NS) were similar suggesting no difference in deployment technique. At follow-up there was more restenosis in the LAD (diameter stenosis: 55.0 +/- 26.4% vs 37.3 +/- 18.1%, and MLD: 1.24 +/- 0.78 mm vs. 1.71 +/- 0.57 mm, P < 0.05 for both comparisons). No differences were seen for injury score (1.09 +/- 0.51 vs 1.01 +/- 0.57; LAD vs RCA) or stent area (6.13 +/- 0.99 vs 6.55 +/- 1.42 mm2). Histomorphometry demonstrated smaller lumen area (2.15 +/- 0.94 vs 2.96 +/- 1.29 mm2) and thicker neointima (0.63 +/- 0.25 vs 0.51 +/- 0.17 mm; all P < 0.05) in the LAD. Multiple linear regression analysis identified the LAD as an independent predictive factor for increased neointima formation. CONCLUSIONS: These observations establish an animal model that is consistent with clinical experience showing that restenosis after stenting is more common in the LAD. The findings may be useful for understanding and developing systemic and local antirestenotic strategies.     

Novel stent system for accurate placement in aorto-ostial renal artery disease: preclinical study in porcine renal artery model

BACKGROUND: Treatment of aorto-ostial renal artery stenosis has been associated with a lower procedural success and higher complication and restenosis rate, as compared to nonostial lesions. The design and delivery of currently available stent systems in ostial lesions can result in inaccurate stent positioning and placement leading to stent protrusion into the parent vessel lumen or geographic miss. A novel stent system (SquareOne Inc., Campbell, CA, USA) has been designed specifically for aorto-ostial lesions in the renal artery. This stent system aims to provide both tactile and visual confirmation of the ostium at the aorta, allow for improved accuracy during stent positioning and placement, provide complete scaffolding of the lesion at the aortic junction to the native vessel, and enable future vessel reaccess. METHODS: Stents (n=12) were implanted in both renal arteries of six swine. For histology, two animals were euthanized immediately after stent implantation, and each two animals were then followed up at 2 and 4 weeks, respectively. Intravascular ultrasound (IVUS) studies were performed immediately after stent implantation and at follow-up. RESULTS: Proper stent positioning and implantation was obtained in all animals. Angiographic and IVUS assessments indicated no dissection or thrombus formation. Histology demonstrated good apposition and endothelialization of the stent strut surface. CONCLUSION: The unique flared shape of this novel ostial stent system allows for improved accuracy during stent positioning and placement, as well as complete apposition and coverage/scaffolding of the similarly-shaped luminal ostium. Future studies will determine if this novel stent system fulfills the unmet clinical need in aorto-ostial stenoses.     

Transradial treatment of bifurcation coronary disease using the Multi-Link Frontier bifurcation stent system

Percutaneous coronary intervention (PCI) for bifurcation lesions is technically limited by the risk of side branch occlusion. Despite using various strategies for the treatment of bifurcation lesions, adequate stent coverage of the side branch ostium remains difficult with conventional stent design. The Multi-Link Frontier stent is a specifically designed bifurcation stent that allows stenting of the main branch and the side branch ostium with a single stent, whilst preserving access to the side branch. Requirement for a 7 French (Fr) guide has discouraged operators from using this device via a transradial approach. We present the immediate results of using the Multi-Link Frontier stent in 5 consecutive cases with bifurcation coronary lesions using a transradial approach.     

Update in management of coronary bifurcation lesions in the drug-eluting stent era

Despite advances in percutaneous coronary interventions, treatment of coronary lesions remains a challenge for the interventional cardiologists. It has been relatively more successful to manage the bifurcation lesions, which entail higher procedural success rates, lower costs, shorter hospitalization and lower clinical and angiographic restenosis rates in comparison with non-bifurcation lesions. After introduction of drug-eluting stents, there has been substantial reduction in event rate and main vessel restenosis, although the side branch ostial residual stenosis and long-term restenosis continue to pose a problem. This article reviews the various techniques being currently employed with varying degrees of success.     

Contrast media as carriers for local drug delivery. Successful inhibition of neointimal proliferation in the porcine coronary stent model.

BACKGROUND: Lipophilic taxanes can be dissolved in contrast media at significantly higher concentration than in saline. As contrast media have occasionally been observed to delineate the contour of coronary arteries for some seconds they may serve as a matrix for an antiproliferative drug aimed at preventing restenosis. The aim of this study was to test a novel taxane-contrast agent formulation for this new approach in the setting of coronary stenting. METHODS AND RESULTS: In cell culture experiments (bovine vascular smooth muscle cells), 60-min incubation with contrast agent-taxane formulations (iopromide-paclitaxel, iopromide-protaxel) induced a significant, concentration-dependent inhibition of vascular smooth muscle cell (VSMC) proliferation over 12 days. Shorter incubation times of 10 and 3 min showed the same efficacy. For in vivo investigation, 16 stents were implanted into the coronary arteries of eight pigs using a 1.3 to 1 overstretch ratio. A control group received iopromide 370 alone while the treatment group was injected with a iopromide-protaxel formulation at a dose of 74 micromol/l, which is far below protaxel levels inducing systemic toxicity. Quantitative angiography and histomorphometry of the stented arteries asserted statistic equality of the baseline parameters between the control and treatment groups. After 28 days, the treatment group showed a marked reduction of the parameters characterizing in-stent restenosis, especially a 34% reduction of the neointimal area. CONCLUSIONS: First evidence is provided that using a contrast agent as solvent for a taxane constitutes a new drug delivery mechanism able to inhibit in-stent restenosis in the porcine restenosis model.     

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.