Ruptured aneurysm: Complex ruptured MCA aneurysm - Ep.1/2

Endovascular Treatments and Antiplatelet therapy for Complex Ruptured Cerebral Aneurysms

Aneurysm repair with microsurgical clipping or endovascular treatments to prevent rebleeding should be performed preferably within 24 to 72 hours of primary rupture. The general goal is to secure the ruptured aneurysm thus support the patient surviving the acute phase, and to perform a durable treatment when the patient is clinically stable. With developments of techniques and devices, endovascular treatments have become not only less invasive but also associated with better short-term outcomes especially for patients with low-grade aneurysmal subarachnoid hemorrhage (Hunt and Hess grades I to III). Complication rates of surgical repair also considerably increase during the vasospastic phase typically one or two weeks after hemorrhage. 

Endovascular Treatment Techniques and Devices

In the acute setting of a ruptured aneurysm, most cases can be done with simple coiling with or without balloon remodeling. Double-microcatheter technique could be considered for aneurysms with multi-saccular or complex shapes. New ultrasoft 3D coils, such as Target Tetra 360 (Fremont, CA: Stryker Neurovascular), tend to keep designed tetrahedral shape allowing stable packing in small wide-necked aneurysms, which might avoid stent-assisted coiling in hemorrhagic patients. 

For wide-necked complex aneurysms up to certain sizes, intrasaccular flow diverters might simplify the procedure and also avoid antiplatelets, especially suitable for certain locations as terminal bifurcation. The initial and long-term occlusion rate of WEB device is slightly higher than stent-assisted coiling for wide-necked bifurcated aneurysms. Among the other four intrasaccular devices approved in Europe, the Luna/Artisse Aneurysm Embolization System (Medtronic), the Medina Embolic Device (Medtronic) might adapt to more irregular shapes; while the Contour Neurovascular System (Cerus), and the Neqstent Coil Assisted Flow Diverter (Cerus) mainly remodel aneurysm necks similar to intrasaccular neck-bridging devices and aneurysm domes could be protected with adjunctive coiling to facilitate immediate thrombus. However, most microcatheters used to deliver the first generation intrasaccular devices are 0.021 inch or larger carrying rupture risks during catheterization and deployment. The new low-profile WEB 17 system combined with steerable microcatheters may mitigate these intraprocedural safety concerns. Ruptured complex and large/giant cerebral aneurysms treated with coiling or intrasaccular flow diversion carry certain risks of device displacement, recanalization or recurrence, such patients might benefit from early follow-up angiography with staged flow diversion. 

Antiplatelet therapy for Ruptured Aneurysms

Ischemic complications of endovascular treatment in ruptured aneurysms are generally more frequent and preventable perioperatively, especially with stent-assisted embolization. Many patients present with new radiological ischemic lesions, regardless of the endovascular procedures used. Patients could be loaded with dual antiplatelets (DAPT) several hours after placement of external ventricular drainage (EVD) or ventriculostomy and 2~3 hours before endovascular intervention. A practical antithrombotic regimen including preoperative loading dose DAPT, intravenous heparin during the procedure, intra-arterial tirofiban during the procedure if stent thrombosis is evident, and other parenteral antiplatelets intraoperatively for rescue stenting, and converted to maintenance dose of oral DAPT (i.e., aspirin 81-100mg daily + clopidogrel 75mg daily/ ticagrelor 60–90mg twice a day/ prasugrel 5-10mg daily) within 24 hours. In-situ replacement for permanent shunt, when necessary, might reduce EVD tract hemorrhage and avoid discontinuation of antiplatelet therapy after intracranial stenting. Platelet function tests, such as the VerifyNow platelet reactivity test, could be performed 1.5–6 hours after antiplatelets are administered to evaluate patients’ responses. The target therapeutic level is <550 Aspirin reaction units (ARUs) and 60–207 P2Y12 reaction units (PRUs). 

Although flow diversion is not considered a first-line strategy for acutely ruptured aneurysms considering its thrombogenicity, it is still a valuable option for blister or dissecting aneurysms. Intravenous antiplatelets bridging with SAPT regimen, has been reported for patients treated with new generation flow diverters with hydrophilic polymer and phosphorylcholine-coated surface and reduced thrombogenicity. In those cases, thromboembolic complication risks are lower with prasugrel or ticagrelor monotherapy than aspirin monotherapy. 

References

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2. Gaudino C, et al. Incidence of intra-procedural complications according to the timing of endovascular treatment in ruptured intracranial aneurysms. Front Neurol. 2023 Jan 11;13:1096651. doi: 10.3389/fneur.2022.1096651.

3. Podlasek A, Al Sultan AA, Assis Z, et al. Outcome of intracranial flow diversion according to the antiplatelet regimen used: a systematic review and meta-analysis. Journal of NeuroInterventional Surgery 2020;12:148-155. doi: 10.1136/neurintsurg-2019-014996.

4. Ospel JM, et al. Antiplatelet Management for Stent-Assisted Coiling and Flow Diversion of Ruptured Intracranial Aneurysms: A DELPHI Consensus Statement. AJNR Am J Neuroradiol. 2020 Oct;41(10):1856-1862. doi: 10.3174/ajnr.A6814.

5. Schirmer CM, et al; SNIS Standards and Guidelines Committee. Antiplatelets and antithrombotics in neurointerventional procedures: Guideline update. J Neurointerv Surg. 2023 Nov;15(11):1155-1162. doi: 10.1136/jnis-2022-019844.

6. Cohen JE, et al. Flow-diverter stents in the early management of acutely ruptured brain aneurysms: effective rebleeding protection with low thromboembolic complications. J Neurosurg. 2021 Apr 16:1-8. doi: 10.3171/2020.10.JNS201642.

7. Ma Y, et al. Single antiplatelet regimen in flow diverter treatment of cerebral aneurysms: The drug matters. A systematic review and meta-analysis. Interv Neuroradiol. 2023 May 23:15910199231177745. doi: 10.1177/15910199231177745.