Advances in Interventional Neuroradiology 2007

Frequency and predictors of endoleaks and long-term patency after covered stent placement for the treatment of intracranial aneurysms: a prospective, non-randomised multicentre experience

OBJECTIVE

We investigated immediate/late endoleaks and long-term patency following stent-graft placement for treatment of intracranial aneurysms located within the distal internal carotid artery (ICA) or vertebral artery (VA).

METHODS

Forty-five aneurysms in 41 patients receiving covered stents in three centres were followed. Outcome measures included aneurysm occlusion rate, endoleaks, late in-stent stenosis rate, clinical improvement, neurological deficiencies and death.

RESULTS

Total aneurysm exclusion was achieved in 69.2% (n = 27), with 30.8% (n = 12) experiencing immediate residual endoleaks. Angiographic follow-up (mean 43.5 ± 14.3 months) revealed that 87.2% (n = 34) were completely occluded with only 12.8% (n = 5) showing residual endoleaks. Predictors of immediate endoleaks in our patient group were stent number (P = 0.023) and stent diameter (P = 0.022), while predictors of late endoleaks in our patient group were stent diameter (P = 0.035) and stent angulation (P = 0.021). Late in-stent stenosis rates were 18.0 ± 13.3 and 29.0 ± 18.5% compared with the period immediately following implantation at 2- and 6-year follow-ups respectively. Smoking (P = 0.017) and stent angulation (P = 0.020) were predictors of late in-stent stenosis.

CONCLUSION

Treating intracranial aneurysms with Willis stent-grafts has an acceptable immediate and late occlusion rate and long-term stented artery patency rate.

The use of flow-diverting stents in the treatment of giant cerebral aneurysms: preliminary results

The treatment of giant cerebral aneurysms has always been a challenge for neurosurgeons and neuroradiologists. Flow-diverting stents (Silk; Pipeline Embolization Device) are new endovascular devices introduced for the treatment of intracranial aneurysms without release of intrasaccular coils. They are tubular bimetallic endoluminal devices with low porosity. We have employed these stents in the Neuroradiology Unit of Bellaria Hospital (Bologna, Italy) since the end of 2008, treating nine patients with giant carotid cerebral aneurysms using nine Silk stents as soon as the device obtained the CE mark. All patients were pretreated with dual antiplatelet medications before surgery. The Silk stents were deployed through a 4F Balt introducer, which ensured an uneventful and very quick procedure. Control CT angiography or MR angiography was typically performed at discharge and one, three, six and 12 months after treatment. Post-treatment results were: four complete occlusions, three near complete occlusions (residual neck flow) with reduced volume of the aneurysm and two more than 50% reduction of intra-aneurysmal flow. A fatal hemorrhagic complication occurred in one patient, probably due to the antiplatelet treatment. The Silk stent seems a very interesting curative device to treat giant aneurysms with preservation of the parent artery and small adjacent branches. Technical improvements will certainly reduce the thrombogenic effect with the related risks.

[Intravascular treatment for acute carotid occlusion with an intracranial tandem lesion]

We present the case of a patient with an acute obstruction in the origin of the internal carotid artery that was associated with occlusion of segment one of the ipsilateral medial cerebral artery and severe neurologic deterioration. We describe the neuroimaging findings (unenhanced cranial computed tomography [CT], CT angiography, CT perfusion studies, and cerebral angiography) and the intravascular treatment (mechanical and pharmacological intra-arterial fibrinolysis). Treatment yielded good morphological and clinical results; we also analyze the follow-up of the patient.

An original flow diversion device for the treatment of intracranial aneurysms: evaluation in the rabbit elastase-induced model

BACKGROUND AND PURPOSE

The potential for successful treatment of intracranial aneurysms by flow diversion is gradually being recognized in the clinical setting; however, the devices currently available (stents) are not designed for flow diversion. We evaluate the long-term response of an appropriately designed flow diversion device in producing thrombotic occlusion of experimental aneurysms.

METHODS

Three different configurations of an original flow diversion device were implanted across thirty elastase-induced aneurysm models in rabbits. Ten animals per device configuration were followed-up for 3 weeks (n=3), 3 months (n=3), or 6 months (n=4), and tissue explanted postsacrifice was sent for histology. The temporal variation in angiographic contrast intensity within each aneurysm was fitted with a mathematical model to quantify the alteration in local hemodynamics caused by the implanted device. A predictive index, called the washout coefficient, was constructed to estimate long-term aneurysm occlusion probabilities immediately after treatment with any flow diversion device.

RESULTS

The device with a porosity of 70% and pore density of 18 pores/mm(2) performed better at occluding aneurysms than devices with 70% porosity, 12 pores/mm(2) and 65% porosity, 14 pores/mm(2). A value of the washout coefficient less than 30 predicted greater than 97% angiographic aneurysm occlusion over a period of 6 months with a sensitivity of 73% and specificity of 82%.

CONCLUSIONS

The flow diversion devices effected successful and stable aneurysm occlusion. Pore density, rather than porosity, may be the critical factor modulating efficacy of such devices.

Periprocedural Drug Therapy in Carotid Artery Stenting: The Need for More Evidence

Carotid artery stenting (CAS) is a widely accepted alternative for patients at high risk for carotid endarterectomy (CEA). However, the role, indications, and evidence for many pharmacologic agents that are used adjunctively in the periprocedural setting have not been established. Several drugs are commonly used before, during, and after CAS, but their uses have not been standardized. Large prospective cohort studies with good validity or randomized trials are needed to demonstrate efficacy, predict outcome, and determine the optimal use of these medications in patients undergoing CAS to improve patient care and obtain optimal outcomes. Several conclusions can be made: (1) dual-antiplatelet therapy (aspirin and clopidogrel) is commonly used for CAS; (2) the most commonly used regimen is aspirin 325 mg and clopidogrel 75 mg per day, but the optimal time of therapy is unknown; and (3) the dose and regimen of other agents used for CAS are not established.