Antiplatelets and antithrombotics in neurointerventional procedures: Guideline update
Authors: Schirmer Clemens M , Bulsara Ketan R , Al-Mufti Fawaz , Haranhalli Neil , Thibault Lucie , Hetts Steven W 
Published: May 2023

BackgroundAntiplatelet and antithrombotic medication management before, during, and after neurointerventional procedures has significant practice variation. This document updates and builds upon the 2014 Society of NeuroInterventional Surgery (SNIS) Guideline ‘Platelet function inhibitor and platelet function testing in neurointerventional procedures’, providing updates based on the treatment of specific pathologies and for patients with specific comorbidities.MethodsWe performed a structured literature review of studies that have become available since the 2014 SNIS Guideline. We graded the quality of the evidence. Recommendations were arrived at through a consensus conference of the authors, then with additional input from the full SNIS Standards and Guidelines Committee and the SNIS Board of Directors.ResultsThe management of antiplatelet and antithrombotic agents before, during, and after endovascular neurointerventional procedures continues to evolve. The following recommendations were agreed on. (1) It is reasonable to resume anticoagulation after a neurointerventional procedure or major bleeding episode as soon as the thrombotic risk exceeds the bleeding risk in an individual patient (Class I, Level C-EO). (2) Platelet testing can be useful to guide local practice, and specific approaches to using the numbers demonstrate marked local variability (Class IIa, Level B-NR). (3) For patients without comorbidities undergoing brain aneurysm treatment, there are no additional considerations for medication choice beyond the thrombotic risks of the catheterization procedure and aneurysm treatment devices (Class IIa, Level B-NR). (4) For patients undergoing neurointerventional brain aneurysm treatment who have had cardiac stents placed within the last 6–12 months, dual antiplatelet therapy (DAPT) is recommended (Class I, Level B-NR). (5) For patients being evaluated for neurointeventional brain aneurysm treatment who had venous thrombosis more than 3 months prior, discontinuation of oral anticoagulation (OAC) or vitamin K antagonists should be considered as weighed against the risk of delaying aneurysm treatment. For venous thrombosis less than 3 months in the past, delay of the neurointerventional procedure should be considered. If this is not possible, see atrial fibrillation recommendations (Class IIb, Level C-LD). (6) For patients with atrial fibrillation receiving OAC and in need of a neurointerventional procedure, the duration of TAT (triple antiplatelet/anticoagulation therapy=OAC plus DAPT) should be kept as short as possible or avoided in favor of OAC plus single antiplatelet therapy (SAPT) based on the individual’s ischemic and bleeding risk profile (Class IIa, Level B-NR). (7) For patients with unruptured brain arteriovenous malformations there is no indication to change antiplatelet or anticoagulant management instituted for management of another disease (Class IIb, Level C-LD). (8) Patients with symptomatic intracranial atherosclerotic disease (ICAD) should continue DAPT following neurointerventional treatment for secondary stroke prevention (Class IIa, Level B-NR). (9) Following neurointerventional treatment for ICAD, DAPT should be continued for at least 3 months. In the absence of new stroke or transient ischemic attack symptoms, reversion to SAPT can be considered based on an individual patient’s risk of hemorrhage versus ischemia (Class IIb, Level C-LD). (10) Patients undergoing carotid artery stenting (CAS) should receive DAPT before and for at least 3 months following their procedure (Class IIa, Level B-R). (11) In patients undergoing CAS during emergent large vessel occlusion ischemic stroke treatment, it may be reasonable to administer a loading dose of intravenous or oral glycoprotein IIb/IIIa or P2Y12 inhibitor followed by maintenance intravenous infusion or oral dosing to prevent stent thrombosis whether or not the patient has received thrombolytic therapy (Class IIb, C-LD). (12) For patients with cerebral venous sinus thrombosis, anticoagulation with heparin is front-line therapy; endovascular therapy may be considered particularly in cases of clinical deterioration despite medical therapy (Class IIa, Level B-R).ConclusionsAlthough the quality of evidence is lower than for coronary interventions due to a lower number of patients and procedures, neurointerventional antiplatelet and antithrombotic management shares several themes. Prospective and randomized studies are needed to strengthen the data supporting these recommendations.