Indications and applications of arterial stents for stroke prevention in atherosclerotic intracranial stenosis

Prevention of neointimal hyperplasia induced by an endovascular stent via intravenous infusion of mesenchymal stem cells

OBJECTIVE

In-stent restenosis after percutaneous transluminal angioplasty and stenting (PTAS) due to neointimal hyperplasia is a potential cause of clinical complications, including repeated revascularization and ischemic events. Neointimal hyperplasia induced by an inflammatory response to the stent strut may be a possible mechanism of in-stent restenosis. Intravenous infusion of bone marrow-derived mesenchymal stem cells (MSCs) has been reported to show therapeutic efficacy for cerebral stroke, presumably by an antiinflammatory effect. This study aimed to determine whether MSCs can reduce or prevent neointimal hyperplasia induced by an endovascular stent.

METHODS

In this study, two types of bare metal stents were deployed using a porcine (mini-pig) model. One stent was implanted in the common carotid artery (CCA), which is considered quite similar to the human CCA, and the other was inserted in the superficial cervical artery (SCA), which is similar in size to the human middle cerebral artery. Angiographic images, intravascular ultrasound (IVUS) imaging, and microscopic images were used for analysis.

RESULTS

Angiographic images and IVUS studies revealed that intravenous infusion of MSCs immediately after deployment of stents prevented in-stent stenosis of the CCA and SCA. Histological analysis also confirmed that inflammatory responses around the stent struts were reduced in both the stented CCA and SCA in the mini-pig.

CONCLUSIONS

Intravenous infusion of MSCs inhibited the inflammatory reaction to an implanted stent strut, and prevented progressive neointimal hyperplasia in the stented CCA and SCA in a porcine model. Thus, MSC treatment could attenuate the recurrence of cerebral ischemic events after stenting.

Neuro Elutax SV drug-eluting balloon versus Wingspan stent system in symptomatic intracranial high-grade stenosis: a single-center experience

BACKGROUND

Intracranial atherosclerotic disease is a well-known cause of ischemic stroke. Following the SAMMPRIS trial, medical treatment is favored over stenting. Drug-eluting balloons (DEB) are widely used in coronary angioplasty, showing better results than bare-surface balloons. There is little evidence of DEB employment in intracranial stenosis, especially of paclitaxel-eluted balloons (pDEB). The Neuro Elutax SV (Aachen Resonance) is the first CE certificated pDEB for intracranial use.

OBJECTIVE

To compare pDEB Neuro Elutax SV (ElutaxDEB) with the Wingspan/Gateway stent system (WingspanStent).

MATERIALS AND METHODS

A single-center, open-label, retrospective cohort study of 19 patients with symptomatic atherosclerotic intracranial high-grade stenosis treated with either ElutaxDEB or WingspanStent from a tertiary stroke center in Switzerland.

RESULTS

Eight patients (42%) received ElutaxDEB. Median clinical follow-up was 10 months for the WingspanStent and 9.5 months for ElutaxDEB (P=0.36). No differences were found in the clinical baseline characteristics, with a median stenosis grade of 80% for the WingspanStent and 81% for the ElutaxDEB (P=0.87). The compound endpoint 'ischemic re-event and/or restenosis' was significantly lower for ElutaxDEB (13% vs 64%; P=0.03, OR 0.08 (95% CI 0.007 to 0.93; P=0.043) than for the WingspanStent.

CONCLUSIONS

The ElutaxDEB may be a promising alternative treatment for patients with symptomatic high-grade intracranial stenosis showing a significantly lower rate of ischemic re-events or restenosis in comparison with the WingspanStent-treated patients with a similar safety profile. Further studies will be needed to definitively elucidate the role of pDEB in the management of symptomatic intracranial high-grade stenosis.

Risk factors associated with in-hospital serious adverse events after stenting of severe symptomatic intracranial stenosis

OBJECTIVES

Severe symptomatic intracranial stenosis is an important cause of stroke. Intracranial stenting is alternatively applied to treat intracranial atherosclerotic disease. However, Stenting versus Aggressive Medical Therapy for Intracranial Arterial Stenosis trial (SAMMPRIS) and Vitesse Stent Ischemic Therapy trial (VISSIT) both demonstrated intracranial stenting were inferior to aggressive medical treatment. But careful patient selection probably can improve the outcome of stenting in intracranial artery stenosis. Therefore, the validation of risk factors associated with serious adverse events (SAEs) after intracranial stenting may contribute to identify patients who are at high risk of stenting therapy and benefit patient selection for stenting.

PATIENTS AND METHODS

Patients who underwent intracranial stenting with symptom attributable to severe (>70%) intracranial stenosis were included in our institution. In-hospital SAEs after procedure were reviewed. Risk factors associated with SAEs were analyzed using multivariable logistic regression analysis.

RESULT

Thirty serious adverse events (5.1%) occurred among a total of 583 patients, with a mean age of 58.1±9.7, including 13 ischemic strokes, 12 brain hemorrhages and 5 deaths. Bivariate analysis and multivariable logistic regression analysis showed age (OR=0.94, 95% CI:0.900-0.983), history of DM (OR=2.439, 95% CI:1.107-5.371), preprocedural mRS score (OR=3.076, 95% CI:1.290-7.336) and lesion site in BA (OR=9.056, 95% CI:1.147-71.524) were risk factors associated with SAEs.

CONCLUSION

History of DM and lesion site in BA were risk factors associated with postprocedural in-hospital SAEs after stenting of severe symptomatic intracranial stenosis. But considering of the limitation of this retrospective study, further studies are necessary to confirm our results.

Schlaganfallprävention: intrakranielle arterielle Stenosen

Intrakranielle arterielle Stenosen (IAS) sind für etwa 6,5–8% aller ischämischen Schlaganfälle verantwortlich. Für Patienten mit einer symptomatischen IAS wurde bislang trotz medikamentöser Sekundärprophylaxe innerhalb eines Jahres ein hohes Reinsultrisiko bis zu 12% in dem zugehörigen Gefäßterritorium beschrieben. Dabei haben IAS mit einem Stenosegrad ≥ 70% das höchste Reinsultrisiko (18%). Die Warfarin vs. Aspirin for Symptomatic Intracranial Stenosis Studie (WASID) führte zu der Empfehlung, dass bei symptomatischen IAS zunächst eine medikamentöse Sekundärprophylaxe mit Azetylsalizylsäure erfolgen sollte. Bei einem unter Thrombozytenfunktionshemmern auftretenden erneuten ischämischen Schlaganfall/TIA im Gefäßterritorium der symptomatischen IAS kann insbesondere bei Stenosen ≥ 70% eine interventionelle (stentgestützte) Angioplastie in einem spezialisierten Zentrum empfohlen werden. Zahlreiche aktuelle Veröffentlichungen legten nahe, dass durch die zunehmende Erfahrung der interventionell tätigen Neuroradiologen die periprozedurale Komplikationsrate zwischen 6 und 7% liegt, das Reinfraktrisiko bei bis zu 7,8% bei IAS > 70% liegen. Allerdings zeigte eine neue randomisierte Studie (SAMMPRIS), die bei symptomatischen IAS eine aggressive medikamentöse Sekundärprophylaxe mit der interven­tionellen Therapie vergliechen hat, dass in dieser Kohorte die Letalität im interventionellen Arm bei 14% lag, im medikamentösen Arm nur bei 5,8%. Eine abschließende Bewertung dieser noch sehr neuen Daten kann aktuell noch nicht erfolgen; ein Zwischenfazit könnte sein, dass eine endovaskuläre Therapie an speziellen Zentren in Betracht gezogen werden sollte wenn Patienten unter doppelter Thrombozytenfunktionshemmung weiterhin symptomatisch sind. Die Leitlinien werden sicher eine Weiterentwicklung und erneute Diskussion erfahren.

Drug eluting stents for symptomatic intracranial and vertebral artery stenosis

The use of bare metal stents (BMS) to prevent recurrent stroke due to stenosis of the cerebral vasculature is associated with high rates of restenosis. Drug-eluting stents (DES) may decrease this risk. We evaluated the performance of DES in a cohort of patients treated at our institution.Consecutive patients treated with DES were identified by a case log and billing records; data regarding procedural details, clinical outcome and angiographic follow-up was obtained by retrospective chart review.Twenty-six patients (27 vessels; 14 vertebral origin (VO); 13 intracranial) were treated. Stenosis was reduced from mean 81% to 8% at the VO and 80% to 2% intracranially. No strokes occurred in the first 24 hours after stenting or at any time point in the VO group during a mean follow-up period of nine months. Among patients with intracranial stents, stroke with permanent disability occurred within 30 days in 1/12 (8%) and after 30 days in 1/11 (9%) with clinical follow-up (mean follow-up, 14 months). Follow-up catheter angiography was obtained in 14/14 (100%) in the VO group at mean eight months and in 8/11 surviving patients (73%) at a mean of ten months after stenting in the intracranial group. The restenosis rate was 21% at the VO (3/14) and 38% (3/8) for intracranial stents. Restenosis at the VO was less frequent than might have been expected from reports utilizing BMS, however, overall restenosis rates appeared higher than previously reported for patients with intracranial DES and comparable with restenosis rates for intracranial BMS.