Stenting for carotid artery stenosis: Fractures, proposed etiology and the need for surveillance

Endovascular Drug Delivery

Drug-eluting stents (DES) and balloons revolutionize atherosclerosis treatment by targeting hyperplastic tissue responses through effective local drug delivery strategies. This review examines approved and emerging endovascular devices, discussing drug release mechanisms and their impacts on arterial drug distribution. It emphasizes the crucial role of drug delivery in modern cardiovascular care and highlights how device technologies influence vascular behavior based on lesion morphology. The future holds promise for lesion-specific treatments, particularly in the superficial femoral artery, with recent CE-marked devices showing encouraging results. Exciting strategies and new patents focus on local drug delivery to prevent restenosis, shaping the future of interventional outcomes. In summary, as we navigate the ever-evolving landscape of cardiovascular intervention, it becomes increasingly evident that the future lies in tailoring treatments to the specific characteristics of each lesion. By leveraging cutting-edge technologies and harnessing the potential of localized drug delivery, we stand poised to usher in a new era of precision medicine in vascular intervention.

Acute ischemia secondary to popliteal artery stent fracture and embolization

Femoropopliteal disease comprises more than one half of lesions in peripheral vascular disease. The treatment modalities for stenosis or occlusion of this anatomic region include femoropopliteal bypass and percutaneous transluminal angioplasty with or without stenting. Our patient developed acute leg ischemia 3 years after stenting, secondary to stent fracture, with distal embolization of stent fragments. Using mechanical thromboembolectomy and superficial femoral artery to below-the-knee popliteal in situ saphenous vein bypass, we were able to restore perfusion to the limb and retrieve fragments of the fractured stent.

Multiphase Flow Hemodynamic Evaluation of Vertebral Artery Stenosis Lesions and Plaque Stability

BACKGROUND

Atherosclerosis is one of the main causes of vertebral artery stenosis, which reduces blood supply to the posterior circulation, resulting in cerebral infarction or death.

OBJECTIVE

To investigate stenosis rates and locations on the development of vertebral artery plaques.

METHODS

Stenosis models with varying degrees and positions of stenosis were established. The stenosis area was comprehensively analyzed using multiphase flow numerical simulation. Wall shear stress (WSS), blood flow velocity, and red blood cell (RBC) volume fraction were calculated.

RESULTS

Blood flow velocity in 30-70% stenosis of each segment tended to increase significantly higher than normal. Downstream of 50% stenosis exhibited turbulent flow; downstream of 70% displayed reflux. Severe stenosis increases the WSS and distribution area. The mixed area of high and low WSS appeared downstream of the stenosis. The RBC volume fraction at the stenosis increased (maximum value: 0.487 at 70% stenosis in the V4), which was 1.08 times the normal volume fraction. Turbulent and backflow regions exhibited complex RBC volume fraction distributions.

CONCLUSION

Flow velocity, WSS, and RBC volume fraction at the stenosis increase with stenosis severity, increasing plaque shedding. Narrow downstream spoiler and reflux areas possess low WSS and high erythrocyte volume fractions, accelerating plaque growth.

Folding Deformation of Open-Cell Stents in Carotid Artery Stenting: Report of Three Cases and Review of Literature

Objective

We describe 3 cases with folding deformation of a PRECISE (Cordis, Miami, FL, USA) stent in carotid artery stenting (CAS).

Case Presentations

The 3 cases with cervical carotid stenosis consisted of 3 males around 80 years old and included 2 symptomatic lesions. During CAS, distal embolic protection was established using a Mo.Ma (Medtronic, Minneapolis, MN, USA) along with a filter device in 2 cases and an Optimo (Tokai Medical Products, Aichi, Japan) along with a filter device in 1 case. For the filter device, either FilterWire EZ (Boston Scientific, Natick, MA, USA) or Spider FX (Covidien, Irvine, CA, USA) was employed. In all cases, a PRECISE stent was deployed after pre-dilation performed using a percutaneous transluminal angioplasty (PTA) balloon with the diameter of 2.5 to 3 mm. Post-dilation was performed after the stent deployment using a PTA balloon whose diameter was about 80% of that of the normal distal internal carotid artery. In all cases, cone-beam CT taken after the deployment of a stent showed folding deformation of the stent. In 2 cases, heavily calcified plaque hampered self-expansion of the stent, which resulted in the stent deformation. On the other hand, in the remaining 1 case, a distal shaft of the Mo.Ma caused the stent deformation, which was likely accelerated by head rotation and cervical compression that was performed to resolve difficulties for a filter retrieval device to pass through the stent, and post-dilation after the stenting.

Conclusion

Heavily calcified plaque and a distal shaft of a Mo.Ma would result in stent deformation.

Assessing the Suitability of the Carotid Bifurcation for Stenting: Anatomic and Morphologic Considerations

OBJECTIVE

Over the years where stents have been used to treat carotid lesions, a great deal has been learned about which anatomical characteristics lead to adverse outcomes. This review summarizes the anatomic and morphologic characteristics of the carotid vasculature that can help guide patient selection and clinical decision-making.

METHODS

Each of the carotid artery anatomy and lesion characteristics that are relevant to carotid stenting are described in detail. These are accompanied with evidence-based outcomes and results.

RESULTS

Data on the prevalence of carotid artery lesions that are unsuitable for stenting are summarized and the implications of these data for practice are discussed, especially as they pertain to transcarotid artery revascularization.

CONCLUSIONS

CAS can be viable option for carotid revascularization, but the lesion must be acceptable and safe for stent placement. There should be thorough assessment to rule out the presence of severe tortuosity, long-segment disease, severe calcification (circumferential or exophytic), mobile-plaque, swollen ICA sign, and carotid diameters outside the acceptable range. In carefully chosen lesions with the absence of the unfavorable characteristics described-TCAR may offer improved periprocedural success, and CAS may attain better long-term durability.

Vascular Lesion-Specific Drug Delivery Systems: JACC State-of-the-Art Review

Drug delivery is central to modern cardiovascular care, where drug-eluting stents, bioresorbable scaffolds, and drug-coated balloons all aim to restore perfusion while inhibiting exuberant healing. The promise and enthusiasm of these devices has in some cases exceeded demonstration of efficacy and even understanding of driving mechanisms. The authors review the means of drug delivery in each device, outlining how the technologies affect vascular behavior. They focus on how drug retention and response are governed by lesion morphology: lipid displacing drug-specific binding sites, calcium inhibiting diffusion, blocking thrombi or promoting luminal washout, and vascular healing steering hyperplastic developments. In this regard, the authors outline the fundamental impact of vascular structure on drug delivery and review the development of contemporary and future devices for coronary and peripheral intervention. They look toward a future where incorporating information on lesion distribution is central to therapeutic success and envision a transition toward lesion-specific treatment for improved interventional outcomes.

Prevention of Stroke with Closed-Cell Stent-in-Stent for Carotid Artery Stenosis Due to Stent Fracture

Objective

Stent fracture is a risk factor for stroke. It has not been fully elucidated whether stent-in-stent procedures can effectively treat stent fractures.

Case Presentation

An 80-year-old man underwent carotid artery stenting (CAS) with an open-cell stent to treat asymptomatic right internal carotid artery (ICA) stenosis. Type III stent fracture occurred during CAS. Six months later, in-stent stenosis progressed on DSA. Repeat CAS with a closed-cell stent was performed. CT showed expansion of the narrowed lumen. The patient remained stroke-free and carotid artery restenosis did not occur for 3 years postoperatively.

Conclusion

Repeat CAS with a closed-cell stent is a viable treatment option for stent fracture.

Failed carotid artery stenting followed by successful surgical intervention: Case report

A 56-year-old female patient with significant carotid stenoses with circumferential plaques, causing localized vascular narrowing, was inappropriately indicated for carotid artery stenting. After placement of a distal embolic protection device in the left internal carotid artery, a stent was inserted; however, it could not be fully deployed due to the rigid, severely calcified vascular walls. The various endovascular attempts to recapture the protection device were futile and, eventually, led to fracture of the guidewire of the device and it remained entrapped together with the stent. Emergency carotid arteriotomy with extirpation of the stent and embolic protection device via carotid thromboendarterectomy was performed. In conclusion, the proper patient selection for carotid artery stenting is of utmost importance.

Carotid Artery Stenting Using Balloon-Expandable Coronary Stent: Intentional Use for Staged Angioplasty

Objective

We report carotid artery stenting (CAS) using balloon-expandable coronary (BECo) stent. The materials in this study consist of 15 cases of high-grade stenosis in internal carotid artery (ICA) in which self-expanding carotid (SECa) stent was not utilized. There were two groups why BECo stent was used instead of SECa stent: alternative group and intentional group. The alternative group was subdivided into two groups: access difficulty of guiding catheter and access difficulty of SECa stent.

Case Presentation

The alternative group included 11 cases (access difficulty of guiding catheter in 10 and access difficulty of SECa stent in 1), and the intentional group included 4 cases. There were four cases using transbrachial approach. All the intentional group cases were the first stage of staged angioplasty (SAP). The second stage of SAP was PTA in two and SECa stent over the BECo stent in two. There was no complication related to CAS.

Conclusion

CAS using BECo stent is one of the choices for the first stage of SAP, if stent placement instead of PTA is required at the first stage. It is also the useful alternative for the patient having difficulty of SECa stent.

"Whiplash" cervical trauma with fracture and migration of carotid stent fragments

Background:

Angioplasty using a carotid stent is a treatment modality for carotid stenosis, with results similar to those obtained with endarterectomy, as demonstrated by important studies. The increasing use of this procedure has also led to a larger number of reports of complications, stent fractures among those. Stent fracture is a rare manifestation and hence needs further studying so that its actual prevalence can be determined, as well as its associated risk factors and proper clinical management. The current study reports the case of a patient who had previously undergone angioplasty with a carotid stent and, after an automobile accident, presented with a stent fracture and distal embolization of fragments thereof with neurological manifestation.

Case Description:

A male patient, 40 years old, presented with a history of previously stent carotid angioplasty. He had been involved in an automobile accident and suffered a stent fracture with distal fragment migration. As he was an asymptomatic patient (NIHSS 0, Rankin zero), we opted for a conservative treatment with oral anticoagulant.

Conclusion:

Angioplasty is an effective treatment for extracranial atherosclerosis and, albeit rare, stent fractures can result in the migration of fragments thereof. This occurrence should be suspected in patients who have sustained severe neck injuries due to sudden deceleration and may be associated with thromboembolism.

The presence of long and heavily calcified lesions predisposes for fracture in patients undergoing stenting of the first part of the subclavian artery

OBJECTIVE

To determine the prevalence and risk factors of subclavian artery stent fractures and to investigate their impact on in-stent restenosis development.

METHODS

One hundred eight patients (65 females; median age, 58.3 years [interquartile range, 53.4-65.5 years]) with steno-occlusive disease of the first part of the subclavian artery who underwent stenting (N = 108 stents; balloon-expandable, 83.3%; self-expandable, 16.7%) between 2005 and 2015 and returned for a fluoroscopic examination of the implanted stents in 2017 were included in our study. Fractures were type I (single strut fracture), type II (multiple strut fractures without deformation), type III (multiple strut fractures with deformation), type IV (multiple strut fractures with acquired transection but without gap), or type V (multiple strut fractures with acquired transection with gap in the stent body). Stent patency was monitored by duplex ultrasound imaging. The Mann-Whitney U and Fisher's exact tests; Kaplan-Meier, receiver operating characteristic, and logistic regression analyses; as well as a log-rank test were used as statistical methods.

RESULTS

The median follow-up was 73.8 months (interquartile range, 35.6-104.2 months). Thirty-eight fractures (35.2%) were detected; fractures were type I in 13, type II in 12, type III in 6, type IV in 4, and type V in 3 cases. Multivariable logistic regression analysis revealed the presence of long (≥20 mm) lesions (odds ratio, 3.3; 95% confidence interval, 1.3-8.4; P = .012) and heavy calcification (odds ratio, 4.7; 95% confidence interval, 1.7-12.7; P = .002) to be significant independent predictors of stent fracture. The primary patency rates were significantly worse (P = .035) in patients with stent fracture compared with those without stent fracture.

CONCLUSIONS

Stent fractures frequently occur. Patients with long and/or heavily calcified lesions require closer follow-up.

Surgical Rescue Retrieval of a Filter Protection Device in Carotid Artery Stenting with Stent Deformation: Case Report and Literature Review

BACKGROUND

Despite the development of neuroendovascular treatment, device-related complications requiring surgical procedures remain. We report a case requiring surgical retrieval of a filter protection device in carotid artery stenting (CAS) with an open-cell stent, due to stent deformation, and review past reports on CAS in which surgical retrieval of devices was required.

CASE DESCRIPTION

An 82-year-old man underwent CAS for symptomatic right internal carotid artery stenosis with severe calcification and tortuosity. Immediately after placement of the open-cell stent, stent deformation was detected and the filter protection device could not be retrieved. All noninvasive device retrieval attempts failed, and the device was ultimately retrieved surgically. After surgery, right cerebral infarction progressed increased, but no permanent deficit was observed.

CONCLUSIONS

As the treatment of cerebrovascular disease shifts from surgical to endovascular approaches, surgeons must be familiar with devices and techniques to manage complications of neuroendovascular treatment.

Sonographic Evaluation of Complications of Extracranial Carotid Artery Interventions

Carotid endarterectomy and carotid artery stenting are among the most common peripheral vascular procedures performed worldwide. Sonography is the initial and often only imaging modality used in the evaluation of iatrogenic carotid arterial injuries. This pictorial essay provides an overview of the clinical and sonographic findings of complications after interventions in the extracranial carotid arteries, including dissection, fluid collections, pseudoaneurysm, thrombosis, thromboembolism, restenosis, and stent deformation. Grayscale, color, and pulsed Doppler imaging findings are reviewed, and correlations with computed tomography, magnetic resonance imaging, and angiography are provided.

Carotid Stent Fracture from Stylocarotid Syndrome

Eagle syndrome is a rare condition resulting from elongation of the temporal styloid process or calcification of its associated stylohyoid ligaments. Although usually presenting with pain or odynophagia, Eagle syndrome has been reported to cause a multitude of neurologic symptoms or vascular complications, some of which can be life-threatening. We present a case in which an endovascularly placed internal carotid artery stent in close proximity to a calcified stylohyoid ligament resulted in stent fracture with subsequent stent and vessel occlusion. We review and discuss the presentation, diagnosis, etiology, complications and treatment options of the syndrome.

Structural Mechanics Predictions Relating to Clinical Coronary Stent Fracture in a 5 Year Period in FDA MAUDE Database

Endovascular stents are the mainstay of interventional cardiovascular medicine. Technological advances have reduced biological and clinical complications but not mechanical failure. Stent strut fracture is increasingly recognized as of paramount clinical importance. Though consensus reigns that fractures can result from material fatigue, how fracture is induced and the mechanisms underlying its clinical sequelae remain ill-defined. In this study, strut fractures were identified in the prospectively maintained Food and Drug Administration's (FDA) Manufacturer and User Facility Device Experience Database (MAUDE), covering years 2006-2011, and differentiated based on specific coronary artery implantation site and device configuration. These data, and knowledge of the extent of dynamic arterial deformations obtained from patient CT images and published data, were used to define boundary conditions for 3D finite element models incorporating multimodal, multi-cycle deformation. The structural response for a range of stent designs and configurations was predicted by computational models and included estimation of maximum principal, minimum principal and equivalent plastic strains. Fatigue assessment was performed with Goodman diagrams and safe/unsafe regions defined for different stent designs. Von Mises stress and maximum principal strain increased with multimodal, fully reversed deformation. Spatial maps of unsafe locations corresponded to the identified locations of fracture in different coronary arteries in the clinical database. These findings, for the first time, provide insight into a potential link between patient adverse events and computational modeling of stent deformation. Understanding of the mechanical forces imposed under different implantation conditions may assist in rational design and optimal placement of these devices.

Delayed cerebral infarction due to stent folding deformation following carotid artery stenting

We report a case of delayed cerebral infarction due to stent longitudinal folding deformation following carotid artery stenting using a self-expandable stent with an open-cell design. The stented segment of the left common carotid artery was divided into two different lumens by this folding deformation, and the separated lumens became restricted with in-stent thrombosis. Although no established method of managing this rare complication exists, a conservative approach was taken with administration of anticoagulant and dual antiplatelet therapy. No neurological symptoms were observed during several months of clinical follow-up after discharge.

Carotid stent deformation: sonographic findings and CT correlation

Carotid artery dissection is a rare but potentially serious complication of endovascular procedures in the carotid arteries. Stent deformation or incomplete expansion may occur following endovascular repair of an iatrogenic carotid artery dissection and may mimic stent fracture. We report an unusual case of deformation of a common carotid artery open cell design stent following endovascular repair of an iatrogenic dissection, which resulted in persistent blood flow between the stent and the wall of the common carotid artery. Sonographic features are described and correlation with intravascular ultrasound and CT is provided.

Carotid false aneurysm after carotid stent fracture: report of a surgical solution

Stent fracture has been well documented in the Literature and in the majority of cases arises from the exposition of the stent to unfavourable stresses and biomechanical forces. We report a case of carotid false aneurysm after stent placement for post-surgery restenosis. Stent fracture is a clinical reality that sometimes should be considered prior to stent deployment and may require monitoring or treatment after occurrence.

Complications and Solutions with Carotid Stenting

Complications of carotid stenting can be classified as neurologic, cardiovascular, death, carotid, access site, device malfunctions, and general and late complications. The risk of most complications is related to readily identifiable patient and anatomic factors. Management and outcome of complications require immediate recognition and a team-based approach to patient care.

Stent fracture in the brachiocephalic trunk

Stents are commonly used as a tool for revascularization of different vascular beds in the body. However, many pitfalls have been reported with their use, such as thrombosis, migration, restenosis or fractures. The latter have been strongly correlated to in-stent restenosis with long-term follow-up. We report a rare case of an early stent fracture in the brachiocephalic trunk with in-stent restenosis and recurrence of symptoms. To our knowledge there has been only one case report of a delayed brachiocephalic stent fracture in the English literature. We believe that our case is the first report of an early stent fracture in the brachiocephalic trunk.

Carotid stent fracture and restenosis management

We report an unusual case of asymptomatic accelerated right carotid artery in-stent restenosis in a patient referred for revascularization of a de novo stenosis of her left internal carotid artery.

Article Commentary: Late Outcomes of Carotid Artery Stenting: A Critical Review

The role of carotid artery stenting (CAS) as an alternative to carotid endarterectomy for the treatment of extracranial carotid occlusive disease for stroke prevention continues to evolve. Although technical and device refinements aimed at making CAS safer continue to this day, safety as measured by 30-day and 1-year outcomes has been the primary recipient of regulatory and practice attention. Relatively less emphasis has been placed on the incidence of recurrent stenosis after CAS and the efficacy of CAS in late stroke prevention. Data on late outcomes of CAS, including factors of potential influence, have been emerging and are addressed in this review.

Clinical relevance and treatment of carotid stent fractures

OBJECTIVE

To review all published reports and investigate the clinical relevance and need for treatment of carotid stent fractures.

METHODS

Electronic and hand-searching of the published literature and the Manufacturer and User Facility Device Experience (MAUDE) database.

RESULTS

Thirteen articles were published. There are 10 case reports and 3 clinical studies. There are 26 reports of fractured stents in the MAUDE database. Fifty-five cases of carotid stent fractures are reported in total. A total of 201 carotid stents were examined in the 3 studies, and the incidence of fractures was 8.9% (18/201). Fractured stents were 22 Xact, 20 Acculink, 6 Precise, 2 Exponent, 1 Nexstent, 1 Genesis, 1 Symbiot, and 2 nonspecified nitinol self-expandable stents. Twenty-seven of the treated carotid lesions were atherosclerotic, 3 restenoses after carotid endarterectomy, 2 postradiational, 1 pseudoaneurysm, and 22 lesions of unknown pathology. Calcification was reported in 15 of the 27 atherosclerotic lesions (55.5%). Time from implantation to fracture ranged from 0 days (fracture during implantation) to 37 months. In 55% of the cases, stent fracture was associated with restenosis. Six patients presented with symptoms. Treatment was reported for 32 patients: 14 patients underwent de novo stent placement, 2 balloon angioplasty, 2 carotid endarterectomy, 2 bypass graft (1 vein, 1 polytetrafluoroethylene), 1 anticoagulation, and 11 patients were followed up.

CONCLUSION

Carotid stent fractures are mainly reported in self-expandable nitinol stents. Plaque calcification may be a risk factor for stent fractures. No difference was observed between open and closed-cell design. Stent fractures were often associated with restenosis and usually were asymptomatic. The actual incidence, clinical relevance, and optimal treatment remain to be clarified from larger prospective studies designed to investigate the issue.

Carotid Artery Stenting for Stenosis Following Cervical Radiotherapy: Report of Early Failure With Associated Stent Fracture

Experience with carotid artery stenting (CAS) as an alternative to carotid endarterectomy (CE) for management of carotid stenosis continues to evolve. We report the case of a 64-year-old man who was treated with bilateral CAS for stenoses, which developed 7 years following thyroidectomy, neck dissection, and radiotherapy. Although long considered an ideal alternative to CE in this clinical setting, CAS in this case was complicated by multiple episodes of recurrent stenosis in his left carotid, managed by balloon angioplasty. Severe, early recurrence in his right carotid associated with a type III stent fracture was managed by CE. Close surveillance and intervention prevented neurologic morbidity. This case, combined with emerging published experience, argues for reappraisal of the general consensus that CAS is an ideal alternative to CE for radiotherapy-associated carotid stenoses.