Bench-Top Comparison of Three Different Types of Stents Used for Treatment of Intracranial Atherosclerotic Stenosis

Benchtop and in Vitro Experiments of Novel Transform Stents for Trigeminal Neuralgia Treatment

BACKGROUND

Trigeminal neuralgia (TN) is a debilitating condition characterized by sudden, excruciating facial pain due to neurovascular compression of the trigeminal nerve. Stent deployment can change the course of the superior cerebellar artery upwards, possibly releasing the root entry zone of the trigeminal nerve. We developed a novel stent, the Transform stent, for TN treatment, and evaluated its mechanical properties using benchtop and in vitro hemocompatibility tests.

METHODS

We compared the performance of Transform and Enterprise stents in treating TN because they share similar self-expanding closed-cell features in the manufacturing process, are derived from nitinol tubes, and are fabricated through a laser-cutting process, but also because only the safety of Enterprise stents deployed in intracranial arteries has been reported clinically. All benchtop measurements, including radial force, trackability, bending stiffness, and conformability, were performed thrice for each stent model, and their average values are presented.

RESULTS

Transform stents showed higher radial forces in vessels of diameters ranging from 1.0 mm than Enterprise stents. The trackability of the Transform stent was better than that of the Enterprise stent in a neurovascular model. Bending stiffness was stronger in the Transform stent whereas conformability was superior in the Enterprise stent. No significant thrombogenic issues were observed in the in vitro hemocompatibility tests.

CONCLUSIONS

This study demonstrated the Transform stent as a potential option and paved the way for innovative endovascular approaches for the future TN treatment. Namely, the study confirmed that the characteristics of Transform stents at benchtop and in vitro evaluations may be used as a first step for studies such as in vivo pre- and clinical studies.

A proposed modern standardized technical approach for symptomatic chronic carotid total occlusion management

Chronic carotid total occlusion (CCTO) is a known cause of ischemic stroke and transient ischemic attack. Symptomatic CCTO is associated with up to 30% risk of recurrent ischemic stroke, despite optimal medical treatment. Notably, a randomized controlled trial reported that previous surgical management did not improve the overall prognosis of these patients. Endovascular treatment of CCTO has been proposed as a feasible strategy to re-establish cerebral perfusion in symptomatic patients. However, its use is controversial and not supported by evidence from randomized clinical trials. Recently, a meta-analysis reported a reasonably high procedural success without an excess periprocedural complication rate, but several steps are needed before the procedure is mature enough to be tested in randomized controlled trials. This review highlights the developments in the endovascular recanalization of CCTO and emphasizes key steps towards standardizing the procedure.

Modern endovascular management of chronic total carotid artery occlusion: technical results and procedural challenges

BACKGROUND

The optimal management of chronic total carotid artery occlusion (CTO) is still debated. Endovascular treatment is being increasingly used with heterogeneous technical and clinical results.

METHODS

Patients with CTO treated with modern endovascular approaches during the past several years (January 2018-December 2021) were retrospectively reviewed.

RESULTS

Twenty patients, with a mean age of 63.7 years, were treated during the study period. Indications for treatment were recurrent stroke in 12 (60%), hemodynamic impairment in 4 (20%), and progressive stroke in 4 (20%) patients. In 6 (30%) patients, the occlusion was limited to the cervical portion, in 5 (25%) to the petrous segment, and in 9 (45%) to the cavernous segment. Technical treatment success was achieved in 80% of cases. In patients with successful recanalization, median pretreatment hypoperfusion volumes dropped from 126 mL (25-75 IQR, 33-224 mL) to 0 mL (25-75 IQR, 0-31.5 mL). Symptomatic procedure-related complications were 30% and permanent procedure-related morbidity-mortality was 5%. Early stent occlusion occurred in 5 (25%) cases. Two cases were asymptomatic and were not retreated, 3 cases presented transient symptoms of which two were successfully recanalized. Stent occlusion was not associated with permanent symptoms. In successfully recanalized patients no intraprocedural emboli were observed.

CONCLUSIONS

In the modern endovascular era, revascularization of CTO is a feasible procedure in most cases, and it may be offered in selected patients. However, the high re-occlusion rate is still a limitation of the technique, underlining the need for more research on the technical procedural and periprocedural management.

A review on femoropopliteal arterial deformation during daily lives and nickel-titanium stent properties

The increasing number of studies on the behaviour of stent placement in recent decades provides a clear understanding of peripheral artery disease (PAD). The severe mechanical loads (axial tension and compression, bending, radial compression and torsion) deformation of the femoropopliteal artery (FPA) is responsible for the highest failure rate of permanent nickel-titanium (Nitinol) stents. Therefore, the purpose of this article is to review research papers that examined the deformation of the natural load environment of FPA, the properties of Nitinol and mechanical considerations. In conclusion, a better understanding of mechanical behaviour for FPA Nitinol stents contributes to increased mechanical performance and fatigue-life.

Update on Clinical Management with Neurovascular Stents

Endovascular stenting has continued to evolve given the new trials. Several new stents have recently been developed to address specific purposes. In this focused review, we discuss the concepts of neurointerventional stents and address the clinical implications. Furthermore, each type of stent is discussed with supporting evidence for clinical utility. In the final component, we argue for continued development and utilization.