Stent fracture associated with drug-eluting stents: clinical characteristics and implications

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.

Percutaneous Treatment of an Injured Coronary Stent Using the Looping Wire Technique

Drug-eluting stent implantation is an effective treatment for coronary artery disease, yet unexpected serious complications during stent implantation are possible. A 70-year-old man with unstable angina presented with a left main bifurcation lesion. Two drug-eluting stents were successfully deployed at the left main bifurcation lesion by the mini-crush technique under intravascular ultrasound guidance. However, after removal of the wire and intravascular ultrasound catheter, the stent of the proximal left circumflex artery was damaged and shortened at the distal edge. We used a looping wire technique to cross the injured stent and we successfully re-dilated the damaged portion of the stent. Finally, we deployed an additional drug-eluting stent at the left circumflex artery over the damaged stent. Our case illustrates the importance of gentle handling of devices during coronary intervention. Furthermore, interventionists should keep in mind the role of intravascular ultrasound when treating this kind of serious complication.

Pathologic Etiologies of Late and Very Late Stent Thrombosis following First-Generation Drug-Eluting Stent Placement

Several randomized and observational studies have reported steady increase in cumulative incidence of late and very late ST (LST/VLST) following first-generation drug-eluting stents (DES: sirolimus-(SES) and paclitaxel-(PES)) up to 5 years. Pathologic studies have identified uncovered struts as the primary substrate responsible for LST/VLST following DES, where delayed arterial healing is associated with stent struts penetrating into the necrotic core, long/overlapping stents, and bifurcation stenting especially in flow divider region. Grade V stent fracture also induces LST/VLST and restenosis. Hypersensitivity reaction is exclusive to SES as an etiology of LST/VLST, whereas malapposition secondary to excessive fibrin deposition is associated with PES. Uncovered struts can be identified in SES and PES with duration of implant beyond 12 months, particularly in stents placed for "off-label" indications. Neoatherosclerosis is another important contributing factor for VLST in DES and bare metal stents (BMS); however, DES shows rapid and more frequent development of neoatherosclerosis than BMS. Future pathologic studies should address the long-term safety of newer generation DES including zotarolimus- and everolimus-eluting stents in terms of the improvement in reendothelialization, decreased inflammation and fibrin deposition as well as a lower incidence of stent fracture-related adverse events, and reduced neoatherosclerosis, which likely contribute to the decreased risk of LST/VLST and better patient outcomes.

Angiographically confirmed stent thrombosis in contemporary practice: insights from intravascular ultrasound

OBJECTIVE

We hypothesized that patients presenting with stent thrombosis (ST) have a high prevalence of stent underexpansion and malapposition when assessed by intravascular ultrasound (IVUS).

BACKGROUND

IVUS can provide mechanistic insight into mechanical factors, including stent underexpansion, malapposition, and fracture that may predispose to ST.

METHODS

All consecutive cases of angiographically confirmed ST from a multicenter registry (from 2005 to 2010) were reviewed. All IVUS images were reviewed off-line for the presence of stent underexpansion, malapposition, and fracture. Kaplan-Meier analysis was used to determine whether use of IVUS at the time of ST was associated with long-term mortality and major adverse cardiovascular events.

RESULTS

IVUS was performed in 32 of 173 subjects with ST (18%). Stent underexpansion was present in 82% of cases and in all cases of early ST, with a mean stent expansion of 0.7 ± 0.23 by MUSIC criteria. Stent malapposition was most frequently observed in very late ST (40%). In-hospital mortality was similar between subjects who had IVUS performed at the time of ST when compared with the non-IVUS group (3.2% vs. 4.3%, P = 0.8). Subjects who had IVUS performed at the time of ST had lower rates of mortality (HR 0.4, 95% CI 0.1-1.6, P =0.2) and major adverse cardiovascular events (HR 0.5, 95% CI 0.2-1.4, P =0.2) at follow-up, but these values were not statistically significant.

CONCLUSIONS

There is a high prevalence of stent underexpansion in early ST, while the prevalence of malapposition is higher in very late ST. Use of IVUS during treatment for ST may identify mechanisms underlying the development of ST.

Incidence and clinical impact of stent fracture after everolimus-eluting stent implantation

BACKGROUND

Stent fracture (SF) after drug-eluting stent implantation has recently become an important concern because of its potential association with in-stent restenosis and stent thrombosis. However, the incidence and clinical impact of SF after everolimus-eluting stent implantation remain unclear.

METHODS AND RESULTS

A total of 1035 patients with 1339 lesions undergoing everolimus-eluting stent implantation and follow-up angiography 6 to 9 months after index procedure were analyzed. SF was defined as complete or partial separation of the stent, as assessed by plain fluoroscopy or intravascular ultrasound during follow-up. We assessed the rates of SF and major adverse cardiac events, defined as cardiac death, myocardial infarction, stent thrombosis, and clinically driven target lesion revascularization within 9 months. SF was observed in 39 of 1339 lesions (2.9%) and in 39 of 1035 patients (3.8%). Ostial stent location and lesions with hinge motion, tortuosity, or calcification were independent predictors of SF. The rate of myocardial infarction and target lesion revascularization were significantly higher in the SF group than in the non-SF group (5.1% versus 0.4%; P=0.018 and 25.6% versus 2.0%; P<0.001, respectively). Stent thrombosis was more frequently observed in the SF group than in the non-SF group (5.1% versus 0.4%; P=0.018). Major adverse cardiac events within 9 months were significantly higher in the SF group than in the non-SF group (25.6% versus 2.3%; P<0.001).

CONCLUSIONS

SF after everolimus-eluting stent implantation occurs in 2.9% of lesions and is associated with higher rate of major adverse cardiac events, driven by higher target lesion revascularization and stent thrombosis.

Detection of Postcoronary Stent Complication: Utility of 64-Slice Multidetector CT

Coronary stent fracture is a known complication of coronary arterial stent placements. Multiple long-term risks are also associated with drug eluting stents. 64-slice multidetector CT (MDCT) coronary angiography has been shown to detect poststent complications such as instent stenosis, thrombosis, stent migration and stent fractures. We report a case of stent fracture in a patient who underwent RCA stenting with associated RCA perforation and almost complete thrombosis of the RCA and peristent fibrinoid collection. This is a rare case of stent fracture with perforation of the RCA. The paper highlights the role of 64-row multidetector computed tomography (MDCT) in evaluation of such poststent placement complications.

Flat panel digital detector cinefluoroscopy late following SES or BMS implantation for detection of coronary stent fracture in asymptomatic patients

BACKGROUND

Coronary stent fracture (SF), is rare and confined mainly in patients treated with sirolimus eluting stents (SES). The role of flat panel digital detector (FPDD) fluoroscopy in detecting SF has not been investigated.

METHODS

Assessment with FPDD fluoroscopy of asymptomatic patients, with 200 SES (Cypher, Cordis, J&J, Miami, Florida, US), and 200 bare metal stents (BMS), at 45.5 ± 15.7 and 38.4 ± 3.9 months post-stenting respectively. SF was defined as discontinuity of stent struts on fluoroscopy. Coronary angiography was reserved for patients with documented SF.

RESULTS

Effective radiation dose was 0.26 ± 0.14 mSv. SF was depicted in 6 (3%) SES, and 1 BMS (0.5%). Stent length was an independent predictor of SF (OR 1.19, 95% CI 1.03-1.4, p=0.024). RCA location and vessel angulation were marginally significant (OR 7.7, 95% CI 0.8-74.2, p=0.077 and OR 5.1, 95% CI 0.8-34, p=0.089). Significant angiographic restenosis was detected in 4 SES (66.6%), and 1 BMS (0.5%). Re-intervention was needed in 3 (42.8%) cases, (2 SES and 1 BMS).

CONCLUSION

Detection of SF with FPDD cinefluoroscopy late following coronary stenting is feasible, involves low radiation and is confined mainly to SES compared to BMS. Application of cinefluoroscopy as part of a routine stent surveillance programme in asymptomatic patients may be more appropriate in "high risk" settings (SES, long stents and adverse angiographic characteristics). The role of invasive imaging and subsequent management of such patients need further studying.

Chronic total occlusion by stent fracture in Kawasaki disease: is recanalisation possible?

Despite various medications for Kawasaki disease, a small number of children have been undergoing interventions for severe coronary artery complications. Transcatheter intervention is a feasible alternative to coronary artery bypass grafting in a patient with chronic totally occluded lesion after Kawasaki disease, even by stent fracture.

Surgical treatment of entrapped intravascular ultrasonography catheter

Intravascular ultrasonography (IVUS) has been widely used in percutaneous coronary artery interventions to ensure optimal stent expansion. Entrapment of the IVUS catheter is potentially lethal. We report a case of successful emergent surgical removal of an entrapped catheter within the sirolimus-eluting stent and coronary revascularization.

[Sirolimus-eluting stent displaced fracture: case report and review of the literature]

Drug-eluting stents have greatly reduced the risk of in-stent restenosis compared to bare metal stents by inhibiting neointimal growth. However, they may carry some long-term risks, especially the risk of late stent thrombosis. Recently, several cases of drug-eluting stent fracture have been also reported. The mechanisms, the diagnosis, the clinical implications and the management of this new complication are not well-known. We report the observation of a new case of displaced, sirolimus drug-eluting stent fracture. To our knowledge, this is the first reported case in France.

Stent fracture at the proximal shaft of the left main stem

Stent fracture is likely to be caused due to mechanical stress at the hinge point or kinking movement at the point of aneurysm formation with stent malapposition. To our knowledge, this is the first published report of stent fracture at the proximal shaft of the left main stem in a patient with acute myocardial infarction.

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.

Impact of Sirolimus-Eluting Stent Fracture on 4-Year Clinical Outcomes

Background—

Although stent fracture (SF) after sirolimus-eluting stent (SES) implantation has been recognized as one of the predisposing factors of in-stent restenosis, it remains uncertain whether SF can increase the risk of major adverse cardiac events (MACE), especially beyond 1 year after SES implantation. The aim of this study was to assess the impact of SF relative to non-SF on 4-year clinical outcomes after treatment with SES of comparable unselected lesions.

Methods and Results—

A total of 874 lesions in 793 patients undergoing SES implantation and subsequent angiography 6 to 9 months after index procedure were analyzed. At 6- to 9-month angiographic follow-up, SF was identified in 70 of 874 lesions (8.0%). In-stent late loss was significantly higher in SF lesions versus non-SF lesions (0.42±0.59 mm versus 0.13±0.49 mm, P <0.001), resulting in a significantly higher in-stent restenosis rate (21.4% versus 4.1%, P <0.001). At 4 years, SF versus non-SF was associated with a significantly higher MACE rate (23.2% versus 12.6%, P =0.014), mainly driven by significantly higher target-lesion revascularization (18.8% versus 10.2%, P =0.029) rate. Adverse effects of SF on clinical outcomes occurred mostly within the first year (17.4% versus 6.6%, P =0.001), with similar MACE rate between 1 and 4 years (5.8% versus 5.9%, P =0.611). No significant differences between SF versus non-SF patients were observed in the cumulative frequency of very late stent thrombosis (2.9% versus 1.4%, P =0.281), death (0% versus 2.1%, P =0.252), or myocardial infarction (5.8% versus 2.9%, P =0.165).

Conclusions—

SF of SES was associated with higher MACE rate up to 1 year, mainly driven by higher target-lesion revascularization, whereas no significant association was evident between years 1 and 4.

A case of a zotarolimus-eluting stent fracture in the left anterior descending artery in a patient undergoing hemodialysis

Although stent fracture after implantation of a drug-eluting stent (DES) is a rare complication, it has been suggested to be a cause of restenosis. To date, most DES fractures have been associated with sirolimus-eluting stents. We describe here a case of a zotarolimus-eluting stent fracture after 8 months of stent placement in a calcified left anterior descending artery lesion in a patient undergoing hemodialysis.

Stent fracture after everolimus-eluting stent implantation

Compared with bare-metal stents, drug-eluting stents (DES) have greatly reduced the risk of in-stent restenosis (ISR) by inhibiting neointimal growth. Nevertheless, DES are still prone to device failure, which may lead to cardiac events. Recently, stent fracture (SF) has emerged as a potential mechanism of DES failure that is associated with ISR. Stent fracture is strongly related to stent type, and prior reports suggest that deployment of sirolimus eluting stents (SES) may be associated with a higher risk of SF compared to other DES. Everolimus eluting stents (EESs) represent a new generation of DES with promising results. The occurrence of SF with EES has not been well established. The present paper describes two cases of EES fracture associated with ISR.

Coronary Stent Fracture

Coronary stent fracture is a relatively uncommon and rare complication of stent implantation. The reported incidence of stent fracture among drug-eluting stents ranges from 1% to 8%. Since 2003, when the use of drug-eluding stents was approved by the FDA for the treatment of coronary atherosclerosis, a number of retrospective and prospective studies and case reports have been published. We reviewed these publications to determine the incidence, predictors, clinical implications, and different management strategies for drug-eluding stent fracture in the coronary arteries. A review of the literature showed that the risk for stent fracture was higher with right coronary artery location, increased vessel tortuosity and angulation prior to stenting, use of overlapping stents, and use of longer stents. A higher risk of bare metal stent fracture was reported in saphenous vein bypass grafts. The authors also report in this issue in the Department “Case Study” a symptomatic fracture of a sirolimus-eluding Cypher® stent in the mid-left anterior descending artery.

In-stent restenosis in the drug-eluting stent era

The introduction of the drug-eluting stent (DES) proved to be an important step forward in reducing rates of restenosis and target lesion revascularization after percutaneous coronary intervention. However, the rapid implementation of DES in standard practice and expansion of the indications for percutaneous coronary intervention to high-risk patients and complex lesions also introduced a new problem: DES in-stent restenosis (ISR), which occurs in 3% to 20% of patients, depending on patient and lesion characteristics and DES type. The clinical presentation of DES ISR is usually recurrent angina, but some patients present with acute coronary syndrome. Mechanisms of DES ISR can be biological, mechanical, and technical, and its pattern is predominantly focal. Intravascular imaging can assist in defining the mechanism and selecting treatment modalities. Based upon the current available evidence, an algorithm for the treatment approaches to DES restenosis is proposed.

Clinical characteristics of coronary drug-eluting stent fracture: insights from a two-center des registry

Stent fracture (SF) has been implicated as a risk factor for in-stent restenosis, but its incidence and clinical characteristics are not well established. Therefore we investigated the conditions associated with stent fracture and its clinical presentation and outcome. Between 2004 and 2007, consecutive cases of SF were collected from the Seoul National University Hospital. Clinical characteristics and outcome of patients with fractured stents were compared with a ten-fold cohort of age and gender matched controls (n = 236). A total of 4,845 patients received percutaneous coronary intervention and 3,315 patients (68.4%) underwent angiographic follow-up. Twenty-eight fractured stents were observed in 24 patients. The incidence of SF was 0.89% for sirolimus-eluting stents (SES) and 0.09% for paclitaxel-eluting stents. Chronic kidney disease, stent implantation in the right coronary artery (RCA), and SES use were independent predictors of drug-eluting stent fracture by multivariate analysis. SF was significantly associated with binary restenosis (11.4% vs 41.7%, P < 0.001) and increased risk of target lesion revascularization (8.1% vs 33.3%, P = 0.001). Patients with SF but without significant restenosis showed excellent outcome despite only medical treatment. In conclusion, SF is associated with increased rates of restenosis and repeat revascularization. Significant risk factors include chronic kidney disease, RCA intervention, and SES use.

Late catch-up phenomenon associated with stent fracture after sirolimus-eluting stent implantation: incidence and outcome

OBJECTIVE

To examine the long-term outcome of the stent fracture (SF) and the potential predictive factors contributing to in-stent restenosis (ISR) in the fractured stent.

BACKGROUND

The SF is thought to be a higher risk of ISR in drug-eluting stent, although SF does not always develop ISR.

METHODS

The consecutive 1,228 de novo lesions in 1,079 patients who underwent sirolimus-eluting stents implantation and assessed by 8 months follow-up coronary angiography were retrospectively analyzed.

RESULTS

One hundred and seventeen SFs (9.5%) were identified in 100 patients and 22 (18.8%) SFs revealed ISR at the first follow-up. In addition, 16 (13.7%) developed new ISRs from 95 residual SFs without ISR prior to the second follow-up. Overall, 38 (32.5%) of all 117 SFs developed ISR, and 16 (42.1%) of 38 SFs occurred in a late phase beyond the first 8 months follow-up. A higher risk of ISR in the SF site was associated with the chronic total occlusion (ISR vs. no ISR: 34.2% vs. 16.5%, P = 0.0304), calcified lesions (55.3% vs. 34.2%, P = 0.0299), and correspondence 89.5% versus 43.0%, P < 0.0001 (SF site occurring at the original target lesion site) in the univariate analysis. The correspondence was identified as the only strong predictive factor for ISR at the SF site according to a multivariate logistic regression analysis (odds ratio 12.6, 95% confidence interval 3.82-53.5, P < 0.0001).

CONCLUSIONS

SF occurring at the site of the original target lesion was a strong independent predictor of ISR. This indicates the need for a careful, long-term follow-up in those situations, even when no significant ISR is initially detected.

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.

Intravascular ultrasound findings of stent fractures in patients with Sirolimus- and Paclitaxel-eluting stents

We compared intravascular ultrasound (IVUS) findings of fractures of sirolimus-eluting stents (SESs) versus paclitaxel-eluting stents (PESs). IVUS findings in 6 PES fractures (all in the right coronary artery) in 6 patients from a clinical trial cohort were compared to 14 SES fractures (8 in the right coronary artery, 2 in the left anterior descending coronary artery, and 4 in the left circumflex coronary artery) in 13 patients from our institutional cohort. Comparing PES fractures to SES fractures, IVUS analysis showed (1) similar frequency of complete stent fracture (1 of 6, 17%, vs 3 of 14, 21%, p >0.99), (2) similar frequency of fracture adjacent to calcified plaque or stent metal overlap (5 of 6, 86%, vs 14 of 14, 100%, p = 0.99), (3) more frequent complete malalignment of proximal and distal fragments in PES strut fractures compared to SES fractures (5 of 6, 83%, vs 1 of 14, 7%, p = 0.002), (4) similar stent lengths (45.2 mm, 23.8 to 50.7, vs 39.3 mm, 22.6 to 73.4, p >0.99), (5) similar fracture lengths (0.5 mm, 0.4 to 0.7, vs 0.7 mm, 0.6 to 1.0, p = 0.14), and (6) larger reference external elastic membrane area (15.0 mm(2), 13.5 to 18.0, vs 10.4 mm(2), 6.8 to 13.6, p = 0.01). In conclusion, malalignment of proximal and distal stent fragments more often occurred in PES fractures compared to SES fractures; otherwise the IVUS features of PES and SES fractures were similar.

Serial angiographic findings and prognosis of stent fracture site without early restenosis after sirolimus-eluting stent implantation

BACKGROUND

Stent fracture is one of the possible causes of in-stent restenosis after sirolimus-eluting stent (SES) implantation. However, long-term prognosis including late restenosis in stent fracture site without early restenosis remains unknown. The aim of this study is to investigate the risk of late restenosis at the stent fracture site without early restenosis after SES implantation.

METHODS

We divided 366 patients with 490 lesions into 2 groups with or without stent fracture based on the first scheduled follow-up coronary angiography (fracture group, 21 lesions; nonfracture group, 469 lesions). The second scheduled follow-up coronary angiography (>15 months after SES implantation) was performed in 83 patients with 124 lesions.

RESULTS

Target lesion revascularization due to late restenosis at the stent fracture site did not occur in the fracture group, but occurred in 5 lesions in the nonfracture group. At the first follow-up, minimal luminal diameter was significantly smaller and percentage diameter stenosis was significantly larger in the fracture group (1.98 ± 0.41 vs 2.52 ± 0.49 mm, P = .001 and 30.5% ± 13.1% vs 13.0% ± 8.8%, P < .0001, respectively). These differences were also present at the second follow-up (P = .01 and P = .007, respectively). In each group, there were no significant changes in minimal luminal diameter, percentage diameter stenosis, and late lumen loss between the first and second follow-up.

CONCLUSIONS

Late restenosis was not observed in stent fracture sites without early restenosis during the midterm follow-up after SES implantation.

Coronary stent fracture: a cause of cardiac chest pain?

Inherent risks of coronary artery stenting include restenosis and thrombosis. More recently, stent fractures (SF) have emerged as a complication. Lengthy coronary stents, overlapping stents, saphaneous vein graft stents, and right coronary artery lesions treated with sirolimus-eluting stents (SES; Cypher, Cordis, Miami Lakes, Florida, USA) are some of the predisposing factors that have been linked to fractures. Early detection and management may help alleviate the complications of SF including acute thrombosis and restenosis at the site of fracture. We present an interesting case of a SES fracture in the left main coronary artery.

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.

Incidence and predictors of drug-eluting stent fracture in human coronary artery a pathologic analysis

OBJECTIVES

The aim of this study was to perform pathologic assessment on stent fracture.

BACKGROUND

Clinically, stent fracture has been reported in 1% to 2% of patients after drug-eluting stent (DES) implantation.

METHODS

High-contrast film-based radiographs of 177 consecutive lesions from the CVPath DES autopsy registry were reviewed. Stent fracture was graded as I (single-strut fracture), II (> or =2 struts), III (> or =2 struts with deformation), IV (with transection without gap), and V (with transection causing gap in stent segment). The incidence of adverse pathologic findings (thrombosis and restenosis) was assessed histologically.

RESULTS

Stent fracture was documented in 51 lesions (29%; grade I = 10, II = 14, III = 12, IV = 6, and V = 9). Lesions with stent fracture had longer duration after implantation (172 days [interquartile range (IQR) 31 to 630 days] vs. 44 days [IQR 7 to 270 days], p = 0.004), a higher rate of Cypher (Cordis Corp., Miami Lakes, Florida) stent usage (63% vs. 36%, p = 0.001), longer stent length (30.0 mm [IQR 22.0 to 40.0 mm] vs. 20.0 mm [IQR 14.0 to 27.3 mm], p < 0.0001), and a higher rate of overlapping stents (45% vs. 22%, p = 0.003). Although fracture with grade I to IV did not have significant impact on the occurrence of adverse pathologic findings such as thrombosis and restenosis, 67% of the grade V fracture lesions were associated with adverse pathologic findings at fracture sites. Longer stent length, use of Cypher, and longer duration of implant were identified as independent risk factors of stent fracture by logistic regression analysis.

CONCLUSIONS

The incidence of stent fracture was 29% lesions at autopsy, which is much higher than clinically reported. A high rate of adverse pathologic findings was observed in lesions with grade V stent fracture, whereas fracture with grade I to IV did not have a significant impact on the pathological outcome.

Stent gap by 64-detector computed tomographic angiography relationship to in-stent restenosis, fracture, and overlap failure

OBJECTIVES

The goal of this study was to define the frequency of stent gaps by 64-detector computed tomographic angiography (CTA) and their relation to in-stent restenosis (ISR), stent fracture (SF), and overlap failure (OF).

BACKGROUND

SF defined by catheter angiography or intravascular ultrasound has been implicated in ISR.

METHODS

A total of 292 consecutive patients, with 613 stents, who underwent CTA were evaluated for stent gaps associated with decreased Hounsfield units. Correlations with catheter coronary angiography (CCA) were available in 143 patients with 384 stents.

RESULTS

Stent gaps were noted in 16.9% by CTA and 1.0% by CCA. ISR by CCA was noted in 46.1% of the stent gaps (p < 0.001) as determined by CCA, and stent gaps by CTA accounted for 27.8% of the total ISR (p < 0.001). In univariate analysis, stent diameter > or =3 mm was the only CCA characteristic significantly associated with stent gaps (p = 0.002), but was not a significant predictor by multivariate analysis. Bifurcation stents, underlying calcification, stent type, location, post-dilation, and overlapping stents were not observed to be predisposing factors. Excessive tortuosity and lack of conformability were not associated with stent gaps; however, their frequency was insufficient to permit meaningful analysis.

CONCLUSIONS

Stent gap by CTA: 1) is associated with 28% of ISR, and ISR is found in 46% of stent gaps; 2) is associated with > or =3-mm stents by univariate (p = 0.002) but not by multivariate analysis; 3) is infrequently noted on catheter angiography; and 4) most likely represents SF in the setting of a single stent, and may represent SF or OF in overlapping stents.

Complete fracture of sirolimus-eluting stent in a saphenous vein graft to left anterior descending artery

Coronary stent fractures have been suggested as a potential new mechanism of restenosis. The mechanical properties of stents were designed not only to prevent vessel recoil, but also to resist the mechanical stress of vessel movement over millions of cardiac cycles. We present a case in which mechanical stress may have contributed to the fracture of a stent implanted in a saphenous vein graft (SVG) to the left coronary artery. The patient was admitted due to chest pain 2 years after receiving a coronary artery bypass graft. A coronary angiography revealed the culprit vessel to be the SVG to the left coronary artery. The graft was stenosed and was stented with a sirolimus-eluting stent. A 6-month follow-up coronary angiography revealed 80% in-stent restenosis with stent fracture. We re-intervened by balloon angioplasty. This is the first report of sirolimus-eluting stent fracture combined with restenosis of SVG in Korea.

Drug-eluting stent fracture and acute coronary syndrome

BACKGROUND

Coronary 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 MATERIALS

A 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.

RESULTS

The 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%).

CONCLUSIONS

Most 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.

Predictors and prognosis of stent fracture after sirolimus-eluting stent implantation

BACKGROUND

Stent fracture is a cause of in-stent restenosis (ISR) after sirolimus-eluting stent (SES) implantation, so this study investigated the incidence, predictors and prognosis of stent fracture.

METHODS AND RESULTS

The 273 consecutive patients (364 lesions) after SES implantation and who had 6-9 month' scheduled follow-up coronary angiography (CAG) were divided into groups with and without stent fracture. Deltaangle was defined as the difference in the angle in the target lesion between diastole and systole before the procedure. The incidence of stent fracture was 4.9% (18 of 364 lesions). Deltaangle in the target lesion was larger in the fracture group (28.3 +/-11.5 degrees vs 12.3 +/-9.0 degrees , P<0.0001). Independent predictors of stent fracture were Deltaangle and total stent length. The rates of binary restenosis and target lesion revascularization (TLR) were higher in the fracture group (33% vs 4.0%, P=0.0002 and 28% vs 3.5%, P=0.0007, respectively). There were no major adverse cardiac events (MACE) in the fracture group during a mean 24-month follow-up after follow-up CAG.

CONCLUSIONS

Predictors of stent fracture were Deltaangle and total stent length. Although stent fracture was associated with ISR and TLR, it was not associated with MACE during long-term follow-up.