A case of early drug-eluting stent fracture

Although stent fracture following femoro-popliteal intervention is well recognized, coronary stent fracture represents an underrecognized entity. Its incidence is low but it represents an important clinical entity as it may complicate with stent thrombosis causing acute coronary syndromes, or may predispose to instent restenosis. Although coronary stent fracture may involve both bare metal stents (BMS) and drug-eluting stents (DES), a recent analysis of the literature indicates that reports of stent fracture have increased since DES was introduced. Furthermore, chronic stretch at specific vessel sites as bends may lead to late occurrence of fracture. We present the case of a patient with a non-ST-segment elevation acute coronary syndrome caused by the early fracture of an everolimus-eluting stent (Xience?) implanted only three days before.     

药物洗脱支架断裂的影像认识

目的借助冠状动脉造影和血管内超声的影像资料,确定支架断裂的发生和类型。方法回顾性分析北京大学人民医院2 021例冠状动脉造影和183例血管内超声（IVUS）影像资料。结果共发现3例患者的6处支架断裂,其中2例经IVUS证实。3例支架断裂均发生在西罗莫司药物洗脱支架,且均发生在冠状动脉介入术后1年以内。冠状动脉造影证实4处支架断裂为完全断裂伴断裂处支架移位。IVUS证实3处支架断裂为完全断裂,2处为部分断裂;1处断裂靠近支架重叠处;1处支架断裂伴有血管瘤形成。结论冠状动脉造影和IVUS可以帮助确定支架断裂的诊断。     

Very late stent fracture associated with a sirolimus-eluting stent

Late stent thrombosis (>1 year after implantation) is a recognised complication involving drug-eluting stents. Stent fracture is increasingly being reported as a complication of drug-eluting stent, and in particular sirolimus-eluting stent use. We report the case of very late sirolimus-eluting stent fracture resulting in an acute coronary syndrome. This case report highlights the need for greater awareness and post-marketing surveillance to detect a potential mechanism for late stent thrombosis in the drug-eluting stent era.     

药物洗脱支架置人术后断裂导致支架内再狭窄的临床分析

目的 探讨药物洗脱支架(DES)置入术后支架断裂与再狭窄的关系及支架断裂的特点.方法 回顾性分析冠状动脉支架置人术后行冠状动脉造影复查的536例患者,实验分为DES组(N=397)和裸金属支架(BMS)组(n=139).分析支架置入术前、术后及复查时的冠状动脉造影图像,找出支架内再狭窄和支架断裂的病例,分析支架断裂和再狭窄的关系以及支架断裂的病变特征及形态特征.结果 DES组和BMS组再狭窄分别为31例和30例(P＜0.01),其中5例发生支架断裂,断裂的支架均为DES,BMS组未见支架断裂,两组差异有统计学意义(P＜0.05).发生支架断裂的5例靶病变均为扭曲病变,支架断裂均发生在血管扭曲成角处.结论 支架断裂是DES置入术后发生再狭窄的原因之一,扭曲病变置入长的DES后可能容易发生支架断裂.     

Incidence and clinical impact of coronary stent fracture after sirolimus-eluting stent implantation.

BACKGROUND: Stent fracture is one of the possible causes of restenosis after sirolimus-eluting stents (SES) implantation. The aim of our study was to evaluate the prevalence and clinical impact of coronary stent fracture after SES implantation. METHODS: From our prospective institutional database, 280 patients were treated solely with SES from August 2004 to June 2005. Among the 280 patients, 256 patients with a total of 307 lesions underwent follow-up angiography on an average of 240 days after the procedure. RESULTS: Stent fractures were observed in eight (2.6%) lesions. Of the eight lesions with stent fracture, five were located in the right coronary artery (RCA), two in the saphenous vein (SV) graft, and one in the left anterior descending coronary artery. The stent fractures were all in the locations that served as hinges during vessel movement in the cardiac contraction cycle. Seven of the eight stent fractures were adjacent to the edge of previously implanted or overlapped stent. Significant multivariate predictors of stent fracture were SV graft location (Odds ratio 35.88; 95% confidence interval 2.73-471.6, P = 0.006), implanted stent length (Odds ratio 1.04; 95% confidence interval 1.01-1.07, P = 0.02), and RCA location (Odds ratio 10.00; 95% confidence interval 1.11-89.67, P = 0.04). In-stent binary restenosis rate was 37.5% and target lesion repeat revascularization rate was 50.0% in patients with stent fracture. CONCLUSIONS: Stent fracture was likely to be affected by mechanical stress provoked by rigid structures and hinge points. Stent fracture might be associated with the high incidence of target lesion revascularization.     

Drug-eluting stent fracture and acute coronary syndrome

BackgroundCoronary stent fracture is an underrecognized entity but has been reported more frequently in the drug-eluting stent (DES) era. Nevertheless, the clinical implications of coronary stent fracture remain unclear.Methods and MaterialsA literature search for reports of DES fracture was conducted via MEDLINE, and the US Food and Drug Administration Manufacturer and User facility Device Experience (MAUDE) database was accessed via the internet and interrogated for reports of stent fracture between January 1, 2003, and April 30, 2008. Each report was reviewed, and clinical information was extracted for analysis.ResultsThe MEDLINE search identified 202 cases of coronary DES fracture, with 95% of cases involving Cypher sirolimus-eluting stents. Clinical information regarding patient presentation was available in 96 cases. Patients presented with ST-elevation myocardial infarction (STEMI) or stent thrombosis in six cases (6%) and with unstable angina or non-STEMI (NSTEMI) in 40 cases (42%). The MAUDE database search identified 337 stent fracture reports, with 97% of cases involving Cypher stents. Clinical information regarding patient presentation was available 193 cases. Patients presented with STEMI or stent thrombosis in 24 cases (12%) and with unstable angina or NSTEMI in 36 cases (19%).ConclusionsMost reports of drug-eluting stent fracture involve Cypher stents. DES fracture can be associated with stent thrombosis, myocardial infarction and angina. However, whether the incidence of such events reported in the literature and in the MAUDE database is representative of all patients experiencing stent fracture remains unclear.     

Coronary aneurysm and stent fracture following stenting of a myocardial bridge

Myocardial bridge is the most common congenital coronary anomaly. We represent an extremely rare case of stent fracture combination with coronary aneurysm following stenting of a myocardial bridge. This 60‐years‐old male patient underwent coronary angiography in the local hospital four years ago. Coronary angiography revealed a myocardial bridge in the distal left anterior descending coronary artery (LAD). A 3.0 mm × 29 mm sirolimus eluting stent was deployed in the distal LAD. Three years later, repeat coronary angiography showed a large coronary aneurysm in the mid segment of the stent. The patient subsequently underwent coronary artery bypass grafting with left internal mammary artery (LIMA) to the distal segment of the LAD. But six months later, another coronary angiography showed a stent fracture in mid portion of the stent associated with a large coronary aneurysm, and the LIMA graft was totally occluded. A possible mechanism of stent fracture was long‐standing and cyclic mechanical stress on the stent by myocardium. These forces over a period of time may lead to metal fatigue and eventually fracture. Based on the observation of fracture and aneurysm in this study, we recommend that myocardial bridge should not be treated with intracoronary stenting. © 2015 Wiley Periodicals, Inc.     

Acute ST-elevation myocardial infarction 6 years following a sirolimus-eluting stent secondary to complete stent fracture

With increasing coronary interventions, coronary stent fracture following implantation of drug-eluting stents is being commonly recognized. Though isolated strut fractures are often only incidental findings, more severe forms of stent fracture with complete transection have adverse clinical outcomes. Most such cases are reported within several months following the index angioplasty. We report an unusual presentation of late stent fracture following a sirolimus-eluting stent, presenting with acute myocardial infarction 6 years after the initial stent implantation. The various mechanisms underlying fracture of drug-eluting stents are reviewed. Because no known mechanisms were noted in our case, unknown factors may also play a role in the genesis of stent fracture. Clinicians need to be aware that such complications may present rarely, extremely late after the index procedure as an acute myocardial infarction.     

Dislodged and mechanically distorted stent stuck within a previously implanted drug-eluting stent

Coronary stent loss during percutaneous coronary intervention is rare and is often associated with significant morbidity. Several retrieval techniques, overlying stent deployment and crushing, and surgical removal can be used to deal with a stent lost in the coronary system. We successfully treated a dislodged and mechanically distorted coil stent stuck within a previously implanted drug-eluting stent (DES) by stent-crush technique. This case might provide insight into the mechanisms responsible for the longitudinal fragility of cobalt alloy and coil-structure stents and stent fracture of DES. In the DES era, careful attention should be paid to such complications when attempting to deliver a stent to a distal vessel through a pre-existing DES.     

Restenosis and stent fracture following sirolimus-eluting stent (SES) implantation.

BACKGROUND: Restenosis still occurs, even with the sirolimus-eluting stent (SES), and the precise mechanisms and the impact of stent fracture on restensosis have not yet been elucidated. METHODS AND RESULTS: Intravascular ultrasound (IVUS)-guided SES implantation was performed in 184 lesions in 151 patients with stable and unstable angina. Serial (pre-, post- and follow-up) quantitative coronary angiography analysis was obtained in 169 lesions in 138 patients (angiographic follow-up rate: 91%) and 12-month clinical follow-up was done in all patients. Restenosis occurred in 13 (7.7%) of 169 lesions. Stent fracture occurred in 4 (2.4%) of 169 lesions at follow-up. Of the 13 restenotic lesions, 8 had intimal hyperplasia, 4 had stent fracture, and 1 had late stent thrombosis at 7 months. Although multivariate logistic regression analysis revealed that minimal lumen area (min-LA) post (p=0.027), total stent length (p=0.003) and diabetes (p=0.032) were significant independent predictors of restenosis, univariate analysis showed that stent fracture was more common in the restenosis than in the non-restenosis groups (p=0.001). CONCLUSIONS: Although min-LA post by IVUS, total stent length by QCA and diabetes are independent predictors for angiographic restenosis, stent fracture occurred in 4 lesions (2.4%) and all of them resulted in restenosis (31% of the restenosis). The impact of stent fracture and its potential role in the development of restenosis deserves further study.     

Meta-analysis of incidence, clinical characteristics and implications of stent fracture

A meta-analysis of published studies was conducted to evaluate the incidence, predictors, and clinical outcomes of stent fractures. Eight studies with 108 stent fractures in 5,321 patients were analyzed using the Bayesian method. Study end points included in-stent restenosis (ISR) and target lesion revascularization (TLR). The mean incidence of stent fracture per patient was 4.0% (95% confidence interval 0.4% to 16.3%). All cases, except 1, were reported with sirolimus-eluting stents. The incidence of stent fracture was 30.4% in the left anterior descending coronary artery, 10.9% in the left circumflex coronary artery, 56.4% in the right coronary artery, < 0.01% in the left main coronary artery, and 1.7% in saphenous vein grafts. The probability of stent fracture was significantly higher in the right coronary artery than in the left anterior descending and left circumflex lesions (p < 0.01). Left main stents were less likely to fracture compared to those in all other vessels (p < 0.01). The probability of stent fracture was significantly increased in overlapping stents (7.5% vs 2.1%, p = 0.01) and long stents (46 vs 32.5 mm, p < 0.01). Lesions with stent fractures had higher rates of ISR (38% vs 8.2%, p < 0.01) and TLR (17% vs 5.6%, p < 0.01). Conversely, the probability of stent fractures was higher in patients with ISR (12.8% vs 2.1%, p < 0.01) and TLR (8.8% vs 2.7%, p < 0.01). In conclusion, although not always associated with clinical sequelae, the probability of ISR and TLR is increased with stent fracture. Conversely, the probability of stent fractures is increased in lesions with ISR or TLR, thus raising the need for surveillance and management guidelines for at-risk patients.     

Usefulness of the evaluation of stent fracture by 64-multi-detector row computed tomography

A 77-year-old man with unstable angina pectoris showed severe coronary stenosis with soft plaque in the left anterior descending coronary artery (LAD) as detected by 64-multi-detector row computed tomography (MDCT). Percutaneous coronary intervention (PCI) with a bare-metal stent to the LAD was performed, and stent fracture immediately after PCI was clearly detected by MDCT. MDCT may be useful for identifying a fractured stent and for management after stent implantation.     

Stent thrombosis due to stent fracture in heavily calcified right coronary artery

Coronary stent fracture is an often unrecognized cause of target vessel failure, however, it has been reported more frequently in the drug-eluting stent era. Clinical presentation of stent fracture may range from benign in-stent restenosis to potentially fatal acute stent thrombosis. Interventional treatment of stent thrombosis can be carried out by high pressure balloon dilatation or second stent implantation into the stented segment after thrombus aspiration. Intravascular ultrasound is mandatory in order to exclude mechanical problems in the background of the stent thrombosis and to achieve good final stent apposition and expansion. We report on a stent fracture induced stent thrombosis occurring in a highly calcified proximal right coronary artery. (Treated previously with rotational atherectomy in the middle part, but not in the aortoostial location.) Our case emphasizes the importance of opitimal plaque modification with rotational atherectomy in a calcified aorto-ostial segment of right coronary artery to prevent long term complications such as stent thrombosis or restenosis due to stent fracture.     

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.     

A completely fractured zotarolimus‐eluting stent in an aortocoronary saphenous vein bypass graft

Drug‐eluting stents (DES) have significantly improved the rate of target vessel revascularization in comparison with bare metal stents. DES fracture was not reported in multicenter randomized clinical trials, but several case reports of DES fracture have been published, mostly with sirolimus‐eluting stents. DES fracture is associated with stent restenosis and thrombosis. We report a zotarolimus‐eluting stent fracture in an aortocoronary saphenous vein graft (SVG) bypass. The patient presented with chest pain and a non‐ST‐elevation myocardial infarction. He underwent cardiac catheterization that showed a complete fracture of a zotarolimus‐eluting stent in the ostium of a sequential SVG to the diagonal and obtuse coronary arteries. His management included coronary angioplasty and retrieval of the proximal fractured segment. We discuss the potential causes for this stent fracture and suggest caution when using a DES in an ostial location of a SVG bypass, especially in a highly mobile vessel. © 2012 Wiley Periodicals, Inc.     

Drug‐eluting stent fracture: Incidence,contributing factors,and clinical implications

Stent fracture has been observed in noncoronary vessels, especially in the superficial femoral and popliteal arteries and with bare metal stents in saphenous vein grafts of coronary arteries. Since the introduction of drug‐eluting stents, stent fractures have also been reported in small studies and case reports. We reviewed these publications to assess what is known regarding the incidence, contributing factors, and clinical implications of drug‐eluting stent fracture in coronary arteries. The reported rate of drug‐eluting stent fracture in coronary arteries ranges from 1 to 8%, although much of the available literature is derived from single‐center studies that are heterogeneous in their study methods. A higher risk of stent fracture may be associated with the right coronary artery location, excessive tortuosity or angulation of the vessel, overlapping stents, and longer stents. The closed‐cell design of the Cypher stent has been associated with increased rigidity that may increase the risk of stent fracture, although these studies did not assess the overall outcomes between the Cypher and Taxus stents in a head‐to‐head comparison. Stent fracture has been shown by most studies to be associated with a statistically increased incidence of focal in‐stent restenosis, and some have shown an increased risk of target lesion revascularization. Other complications observed with stent fracture include stent thrombosis, coronary aneurysms, myocardial infarction, and sudden death. © 2009 Wiley‐Liss, Inc.     

Late giant coronary aneurysm associated with a fracture of sirolimus eluting stent: a case report

A 73-year-old female underwent percutaneous coronary intervention (PCI) because of stable angina. An elective PCI for the RCA lesion was first performed with deploying sirolimus eluting stents (SES). Three weeks later, PCI was also provided in the residual LAD lesion. Eight months later, she presented with new angina. CAG revealed an in-stent restenosis in the mid LAD and a large eccentric saccular coronary aneurysm (17 mm x 9 mm) at the proximal RCA. Intravascular ultrasound (IVUS) showed absence of stent struts around the orifice of aneurysm, which suggested a fracture of SES stent. The entry of coronary aneurysm was finally sealed with a polytetrafluoroethylene-covered stent. This report documented a rare case of late giant coronary artery aneurysm associated with a fracture of SES.     

Coronary stent fracture in a saphenous vein graft to right coronary artery--successful treatment by the novel use of the Jomed coronary stent graft: case report and review of the literature

Coronary stents ultimately owe their success to the mechanical scaffolding effect that they provide. The mechanical properties of these metallic stents were designed not only to provide radial strength so as to prevent vessel recoil, but also to be able to resist the mechanical stress of vessel movement over millions of cardiac cycles. We present a case whereby the latter mechanical stresses may have contributed to the fracture of a stent implanted in the saphenous vein graft to the right coronary artery. We demonstrated that the point at which the stent fracture occurred coincided with an area of maximal graft movement. Our patient presented with acute myocardial infarction due to graft occlusion 3 months after stent implantation. We re-intervened by deploying a Jomed coronary stent graft, consisting of 2 layers of stent, to cover the stent fracture, thereby providing optimal support to this area of high mechanical stress, resulting in a good long-term clinical outcome. The novel use of a Jomed coronary stent graft for this indication has not been previously described. Review of the literature indicates that factors that may predispose to stent fracture include location in the right coronary vein graft, long stents, overlapping stents and stent over-expansion.     

The use of intra-coronary optical coherence tomography for the assessment of sirolimus-eluting stent fracture

Drug-eluting stents (DES) have made a tremendous impact on the practice of percutaneous coronary intervention. Recently however, long-term DES failures have become a focal point, particularly with restenosis and thrombosis. An uncommon, yet important cause of DES failure is stent fracture. Of the two established first generation DES, the sirolimus-eluting stent (SES) has been particularly linked to cases of stent fracture, likely as a result of its closed cell design compared with other DES employing an open cell system. We present 2 cases of SES fracture confirmed using high-resolution intravascular optical coherence tomography giving unique insights into the in-vivo appearance of this complication.     

Current and evolving stent evaluation by coronary computed tomographic angiography

Objectives : To demonstrate the variety of stent abnormalities that may be evaluated by coronary computed tomographic angiography (CTA). Background : The application of CTA to the evaluation of coronary stents has focused almost entirely on the detection of in‐stent restenosis. Methods : All CTA performed for stent evaluation at a single institution were reviewed. Results : In addition to in‐stent restenosis, stent fracture, and overlap failure, a multiplicity of stent‐related problems not previously addressed by CTA was categorized and illustrated: late stent thrombosis, jailed branches, edge stenosis, bifurcation stents, inadequate stent expansion, stent aneurysms, peri‐stent plaque, and stenting into bridged myocardium. Conclusions : CTA may be used to evaluate the full range of stent‐related problems. This work provides the framework for future studies validating these applications. © 2011 Wiley‐Liss, Inc.