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.     

Stent fracture associated with drug‐eluting stents: Clinical characteristics and implications

Objective : To evaluate the clinical characteristics and implications of stent fracture in drug‐eluting stents. Background : Approximately 2.5 million drug‐eluting stents are implanted every year worldwide. In 10 randomized controlled trials involving 2,602 patients, no incidence of stent fracture was recognized or reported. Methods : From April 2003 to December 2005, 2,728 patients underwent drug‐eluting stenting. The angiograms of all 530 patients who underwent repeat angiography were analyzed to identify the presence of stent fracture. We then documented the incidence of adverse events associated with drug‐eluting stent fracture and systematically analyzed the clinical, procedural, and structural factors, which might predispose to stent fracture. Results : Stent fracture was identified in 10 patients. None of these fractures were detectable at the time of stent placement. The median time interval from stent implantation to detection of fracture at repeat angiography was 226 days (range, 7–620 days). Adverse clinical outcomes associated with stent fracture occurred in 7 patients (6 patients had binary restenosis and 1 patient had stent thrombosis), all necessitating repeat intervention. Analysis of potential predisposing clinical, procedural, and structural factors revealed that 4 patients had excessive tortuosity in the proximal segment, and overlapping stents were used in 5 cases. All fractures occurred in sirolimus‐eluting stents. Conclusions : Stent fracture may represent a new potential mechanism of restenosis and stent thrombosis in drug‐eluting stents. Predisposing clinical and procedural factors may be vessel tortuosity and use of overlapping stents. The most important predisposing factor, however, may be stent structure, since all fractures occurred in sirolimus‐eluting stents. © 2006 Wiley‐Liss, Inc.     

Decreased risk of stent fracture‐related restenosis between paclitaxel‐eluting stents and sirolimus eluting stents: Results of long‐term follow‐up

Objective: To compare the outcomes between paclitaxel‐eluting stents (PES) and sirolimus‐eluting stents (SES) for the treatment of drug‐eluting stent (DES) fracture. Background: DES fracture is considered as an important predictor of in‐stent restenosis (ISR). However, little data are available evaluating the optimal treatment for this complication of coronary stenting. Methods: From January 1, 2004 to December 31, 2008, patients with DES ISR treated with a second DES were identified and evaluated for stent fracture. Stent fracture was defined by the presence of strut separation in multiple angiographic projections, assessed by two independent reviewers. Target lesion revascularization (TLR) at 6 and 12 months were the primary end points. Results: Of 131 lesions with DES ISR treated with a second DES, we found 24 patients (24 lesions, 18.2%) with angiographically confirmed stent fracture. Of these, 20 patients (20 lesions) treated with either PES (n = 11/55%) or SES (n = 9/45%) were included in the study. TLR at 6 months occurred in 9% of patients treated with PES and 22% of those treated with SES (P = 0.41). After 12 months, TLR was 9% and 55.5%, respectively (P = 0.024). Conclusions: This study demonstrates a high incidence of stent fracture in patients presenting with DES ISR in need of further treatment with another DES. The suggested association between treatment of stent fracture‐associated DES ISR with PES as compared with SES, and better long‐term outcomes, is in need of confirmation by larger prospective registries and randomized trials. © 2011 Wiley Periodicals, Inc.     

In‐Stent Restenosis

The introduction of coronary stents marked a major turning point in the practice of interventional cardiology. Whereas the efficacy of balloon angioplasty was challenged both by immediate mechanical complications and by a high incidence of restenosis, coronary stents offered cardiologists a means by which to not only augment immediate procedural success, but also to reduce the incidence of restenosis following coronary intervention. However, despite technological advances and an improved understanding of the restenotic process, the overall rate of in‐stent restenosis following bare metal stent implantation remains high. Although the introduction of drug‐eluting stents has further reduced the incidence of restenosis, the “real‐world” application of drug‐eluting stents in increasingly complex lesion and patient subsets has given way to the even greater clinical challenge of managing drug‐eluting stent restenosis. Although the standard treatment of bare metal stent restenosis typically involves placement of a drug‐eluting stent, the optimal therapeutic approach to drug‐eluting stent restenosis remains less defined. The issue of in‐stent restenosis (especially following implantation of a drug‐eluting stent) remains a clinical challenge, and investigation into therapeutic options remains ongoing. As technology evolves, such investigation will likely incorporate novel approaches including drug‐coated balloons novel stent designs.     

Acute coronary syndrome due to early multiple and complete fractures in sirolimus‐eluting stent: A case report and brief literature review

Despite drug eluting stents (DES), as compared to bare metal stents, have reduced in‐stent restenosis, complex and long lesions remains a challenge for interventional cardiologist. Their treatment is often associated with an unfavorable outcome, related to in‐stent restenosis, stent thrombosis, and target lesion revascularization. These complications may derive from the contact between metallic structures and coronary artery endothelium, and consequent overexpression of platelet activating factors, growth factors, and inflammatory cytokines. Recently, an additional mechanism has emerged as new cause of these complications: “stent fracture.” Several factors are involved in this phenomenon including material and stent platform, target vessel features, stent implantation technique, and implant duration. We reported a case of 69 years old man with rare early and complex DES fractures on right coronary that caused acute coronary syndrome 36 hr after a previous percutaneous coronary intervention.© 2012 Wiley Periodicals, Inc.     

Markedly different tissue types on optical coherence tomography imaging in a patient with multiple lesion drug‐eluting stent in‐stent restenosis

The treatment of in‐stent restenosis after drug‐eluting stent (DES) implantation remains a major clinical challenge. Optical coherence tomography (OCT) imaging at the time of presentation can provide important information on mechanical factors contributing to stent failure as well as on tissue characteristics of the in‐stent neointimal tissue. We report a case of markedly different tissue types—characterized by heterogeneous and homogeneous signal intensity—observed in a patient with multiple lesion DES in‐stent restenosis. Although both lesions were initially successfully treated with drug‐coated balloon angioplasty, the patient presented with recurrent in‐stent restenosis in the lesion with homogeneous tissue characteristics. Future studies should evaluate whether OCT tissue characterization can guide optimal treatment strategy in patients with DES restenosis. © 2016 Wiley Periodicals, Inc.     

Unprotected left main bifurcation restenosis treated with a 2‐stent technique

The present case report refers to the percutaneous treatment of severe left main stem stenosis as a consequence of proliferative in‐stent restenosis of left circumflex coronary with retrograde involvement. A reverse mini‐crush technique with 2 stents was described. © 2012 Wiley Periodicals, Inc.     

Late lumen enlargement induced by drug coated balloon in the patient with PTFE‐covered stent restenosis

We report a case of percutaneous coronary intervention with drug coated balloon (DCB) for the in‐stent restenosis of polytetrafluoroethylene‐covered stent. One year follow‐up angiography was excellent and in‐stent lumen enlargement compared with the postprocedure and 6‐months follow‐up was demonstrated by optical coherent tomography. This case suggested the utility of DCB as a therapeutic option for covered‐stent restenosis.     

Long‐term complication after LM bifurcation treatment

Two months after left anterior descending (LAD) artery and left circumflex (LCx) artery bare metal stent implantation, a proliferative subocclusive in‐stent restenosis in LCx coronary with severe LM coronary (LM) involvement developed. The present clinical case describes a simplified strategy for unprotected LM percutaneous coronary intervention using two bioabsorbable biolimus‐eluting stents without involvement of the LAD coronary using an “L” technique. © 2010 Wiley‐Liss, Inc.     

Stent fracture: an unusual cause of late restenosis after sirolimus-eluting stent placement.

Stent fracture is uncommon but may have consequences including restenosis. To date, stent fractures reported have been related to aggressive post dilation. We describe a case that involves fracture of a stent deployed to nominal pressure. Unlike most stent fractures reported that involve stent struts only our case demonstrated circumferential disruption with complete separation of the stent segments.     

Long‐term clinical,angiographic, and intravascular ultrasound outcomes of biodegradable polymer‐coated sirolimus‐eluting stents

Background: The residual drug carriers on drug‐eluting stents (DES) surfaces are considered to be one of the most significant reasons causing late thrombosis. There is no documented data currently available on the safety/benefit profile beyond 6 months of EXCEL stent, a novel sirolimus‐eluting stent with biodegradable polymer coating, in treating patients with coronary artery disease (CHD). Objective: To evaluate the long‐term efficacy and safety of EXCEL stent on treating CHD patients. Methods: Between February and March 2006, a consecutive cohort of complex patients treated with the EXCEL stent was prospectively enrolled in this single‐center registry. Antiplatelet protocol was 6‐month dual antiplatelet therapy with clopidogrel and aspirin followed by aspirin alone indefinitely. The primary outcome was major adverse cardiac events (MACE) at 12 months. Secondary outcomes included in‐segment and in‐stent late lumen loss and binary restenosis rate measured by quantitative coronary angiography (QCA) analysis at 8 months postindex PCI procedure. Results: A total of 100 patients with 153 lesions were included in this analysis. Most lesions (83.0%) were classified as complex (B2/C). At 12 months, four patients (4.0%) experienced MACE, which were four target‐lesion revascularizations due to in‐stent restenosis (ISR). All patients received follow‐up up to 24 ± 0.4 months and no cardiac death, MI, and in‐stent thrombosis occurred during the 6 months of dual antiplatelet therapy or the subsequent 15 months of aspirin treatment alone. QCA analysis of 112 lesions from 75 patients showed 3.6% (4/112) in‐stent lesion restenosis, 5.4% (6/112) in‐segment lesion restenosis, 0.12 ± 0.34 mm in‐stent late lumen loss, and 0.08 ± 0.35 mm in‐segment late lumen loss. Conclusions: In this single‐center experience with complex patients and lesions, the EXCEL^TM stent implantation with 6‐month dual antiplatelet treatment proved to markedly reduce the incidence of 24‐month ISR and MACE. These preliminary findings require further validation by large scale, randomized trials. © 2008 Wiley‐Liss, Inc.     

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.     

High energy excimer laser to treat coronary in‐stent restenosis in an underexpanded stent

Balloon refractory calcific coronary plaques remain a technical challenge. Stent underexpansion is known as a major cause of restenosis and thrombosis. We report a case of in‐stent restenosis 5 months after stent suboptimal implantation in a noncompliant calcific atherosclerotic plaque which could not be disrupted by repeated prolonged high‐pressure balloon inflations. High‐energy excimer laser use altered underlying lesion morphology, allowing full stent apposition. Advances in equipment and technique have allowed more frequent use of high energy excimer laser technology during percutaneous coronary angioplasty with very low rates of complications. Laser technology represents a useful tool to overcome resistant lesions during percutaneous coronary interventions. © 2008 Wiley‐Liss, Inc.     

3‐year follow‐up of 100 consecutive coronary bifurcation lesions treated with Taxus stents and the crush technique

Objectives : To determine the 3 year safety and efficacy of crush‐stenting with paclitaxel‐eluting stents. Background : The optimum two‐stent strategy for treatment of coronary bifurcation lesions is undetermined. Crush‐stenting is advocated to minimize restenosis through complete circumferential stent coverage; long‐term follow‐up data are lacking. Methods and Results : In a single center prospective registry, 100 consecutive patients with bifurcation lesions were treated with the Crush technique. The vast majority (93%) were true bifurcations, predominantly involving the left anterior descending and diagonal arteries. Technical success was 98%. Final kissing balloon dilatation, which became standard practice during the study, was attempted in 68 patients and successful in 51. Abciximab was used in all cases. There were no peri‐procedural stent thromboses. Follow‐up was 100% at 3 years. Symptom‐driven target lesion revascularisation was 8% at 3 years. Cumulative 3‐year major adverse cardiac events was 28% (7 cardiac deaths, 15 myocardial infarctions, 11 target vessel revascularisations). Absence of a final kissing inflation predicted repeat revascularisation but not death, infarction or stent thrombosis. Three probable stent thromboses occurred, of which two were very late. Conclusion : Where a two‐stent bifurcation strategy is required, Crush‐stenting with paclitaxel‐eluting stents is safe and effective in the long‐term. Failure to perform a final kissing dilatation increases the likelihood of revascularisation but not other adverse events. © 2009 Wiley‐Liss, Inc.     

Angiographic and intravascular ultrasound follow up of paclitaxel‐ and sirolimus‐eluting stent after poststent high‐pressure balloon dilation: From the poststent optimal stent expansion trial

Objectives : The aims of this study were to identify the efficacy of optimal stent expansion (OSE) according to the Multicenter Ultrasound Stenting in Coronaries Study (MUSIC Study) criteria in drug‐eluting stent (DES) and compare paclitaxel‐eluting stent (PES) to sirolimus‐eluting stent (SES). Background : Although poststent high‐pressure balloon dilatation is proposed after bare metal stent implantation according to OSE, defined by the criteria of the MUSIC Study, very little data are available in DES. Methods : Two hundred fifty patients (M:F = 149:101; age, 61.5 ± 9.2 years) who underwent 9‐month follow‐up angiography in the Poststent Optimal Stent Expansion Trial (POET) were included in this study. We assessed angiographic in‐stent restenosis (ISR) and neointima volume (NV) using IVUS at 9 months. Results : At 9‐month follow up, there were no significant differences in ISR and NV index (NV/stent length, mm²) between patients with and without OSE. However, the rate of ISR and NV index were higher in PES [ISR: 18 (13.7%) and 4 (3.4%), P = 0.004; NV index: 1.02 ± 0.99 mm² and 0.21 ± 0.37, P < 0.001 in PES and SES]. Conclusions : OSE according to the MUSIC Study criteria was not related to ISR and NV in the DES era but PES had a significantly higher ISR rate and NV than SES after poststent high‐pressure balloon dilatation. © 2010 Wiley‐Liss, Inc.     

Membranous diaphragm formation after simultaneous kissing stenting with sirolimus‐eluting stents for the left main bifurcation

Two patients who underwent simultaneous kissing stenting with sirolimus‐eluting stents in the left main coronary artery were investigated with optical coherence tomography (OCT) at just more than 1 year postoperatively. In both cases, follow‐up angiogram indicated complete coverage of the new metal carina with a membranous diaphragm, yet OCT showed varying tissue‐coverage patterns transitioning from stent inflow to stent outflow. These patterns included single‐strut coverage, bridge‐like membrane formation between more than 1 strut, and end‐to‐end coverage of the carina; no uncovered stent struts were detected. OCT also demonstrated mixed patterns of tissue characteristics on the metal carina, ranging from poor endothelialization to modest neointima formation. These varying tissue characteristics suggest that the process of tissue coverage in the metal carina is different from that occurring on the vessel wall; this may indicate delayed healing in the carina. © 2013 Wiley Periodicals, Inc.     

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.     

Aneurysm formation after drug‐eluting balloon treatment of drug‐eluting in‐stent restenosis: First case report

A 55‐year‐old male underwent paclitaxel‐eluting stent implantation in a bifurcation lesion of his left anterior descending artery (LAD) during an episode of unstable angina in 2008. A late in‐stent restenosis developed 15 months after implantation of the drug‐eluting stent (DES) and was treated with paclitaxel eluting balloon. Two months later, during angiography for functional assessment of the significance of lesions in the circumflex artery, an aneurysm at the place of drug‐eluting balloon (DEB) inflation was observed. The patient was left on double antiplatelet therapy and scheduled for clinical observation after 3 months and control coronary angiography after 6 months for aneurysm progression follow‐up. © 2012 Wiley Periodicals, Inc.     

Metal allergy to everolimus‐eluting cobalt chromium stents confirmed by positive skin testing as a cause of recurrent multivessel in‐stent restenosis

A 54‐year‐old woman treated with cobalt‐chromium everolimus eluting stents (CoCr‐EES) for her left distal circumflex and diagonal branch lesions suffered from repeated in‐stent restenosis in both lesions. Neointimal proliferation occurred rapidly and almost simultaneously in the two lesions. The cause was established to be metal allergy, as determined by patch tests which were strongly positive for bare metal stents and weakly positive for CoCr‐EES. Following the third successive angioplasty, we initiated treatment with prednisolone (30 mg daily) and the anti‐allergic and anti‐proliferative drug tranilast (300 mg daily). An elective angiogram performed 3 months later showed no evidence of in‐stent restenosis in any of the stented lesions. Furthermore, the patient has remained angina‐free for 15 months. The unique features of this case include: (1) near‐simultaneous repeated multivessel in‐stent restenosis in a patient with skin test‐documented metal allergy to cobalt‐chromium stents; (2) adjunctive systemic medical therapy with prednisolone and tranilast appeared to terminate the malignant restenotic cycle. © 2015 Wiley Periodicals, Inc.     

Outcome of patients treated by a novel thin‐strut cobalt‐chromium stent in the drug‐eluting stent era: Results of the SKICE (Skylor in real world practice) registry

Objectives : To investigate the outcome of patients undergoing percutaneous coronary interventions (PCI) with implantation of a new thin‐strut cobalt‐chromium bare‐metal‐stent (BMS) in the drug‐eluting‐stent (DES) era. Background : Despite the contemporary penetration of DES in the clinical practice, a relevant percentage of patients are still treated by BMS. Data on clinical outcome of novel BMSs are lacking. Methods : This is a single‐centre‐registry enrolling patients treated by Skylor? stent implantation. During the study, the criteria for BMS selection adopted at our institution (“internal” criteria) were as follows: (1) limited compliance to prolonged double antiplatelet therapy, (2) ST‐elevation myocardial infarction (STEMI) or saphenous vein grafts (SVG) interventions, and (3) in the absence of these conditions, noncomplex (no bifurcations, no chronic total occlusions) lesions considered at low restenosis risk on the basis of arbitrary angiographic criteria (short lesions, large vessels). Primary and secondary end‐points were respectively major adverse cardiovascular events (MACE) and target vessel failure (TVF) up to 9‐month. Results: A total of 150 patients were treated with Skylor? stent on 169 lesions. At 9‐month follow‐up, MACE occurred in 12 patients (8.0%) and TVF in 21 lesions (12.4%). By multivariable analysis, the predictors of MACE were Euroscore≥9 and ejection fraction < 30% while the predictors of TVF were the absence of the angiographic criteria of low restenosis risk and ejection fraction < 30%. Conclusions: In the DES era, the use of a last‐generation BMS in patients with limited compliance to double antiplatelet therapy, STEMI or SVG interventions, and noncomplex angiographic lesions may be associated with acceptable clinical outcome. © 2009 Wiley‐Liss, Inc.