Antithrombotic therapy and intracranial bleeding in subjects with sporadic brain arteriovenous malformations: preliminary results from a retrospective study

Antiplatelets and antithrombotics in neurointerventional procedures: Guideline update

BACKGROUND

Antiplatelet 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.

METHODS

We 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.

RESULTS

The 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).

CONCLUSIONS

Although 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.

[Endovascular treatment of aneurysms associated with cerebral arteriovenous malformations]

There are proximal, distal and intranidal AVM-associated aneurysms (G. Redekop, 1998).

OBJECTIVE

To evaluate treatment outcomes in 120 patients with AVM-associated aneurysms.

MATERIAL AND METHODS

We analyzed treatment outcomes in 639 patients with cerebral AVM who underwent 1992 endovascular procedures between 2010 and 2019. AVM-associated aneurysms were found in 120 (18.8%) cases: 81 (67.5%) patients with 69 proximal and 29 distal aneurysms, 33 (27.5%) AVMs with intranidal aneurysms and 6 (5%) aneurysms without hemodynamic connection with AVM. One hundred and one malformations (16.9%) out of 596 supratentorial AVMs and 19 (44.2%) out of 43 subtentorial AVMs were associated with aneurysms.

RESULTS

Intracranial hemorrhage occurred in 349 (53.3%) out of 639 patients with AVM: 97 (80.8%) out of 120 patients with AVM-associated aneurysms and 252 (48.6%) out of 519 ones with AVM and no aneurysms. All 33 patients with intranidal aneurysms in the AVM structure and 18 (94.7%) out of 19 patients with AVM-associated aneurysms and AVM in posterior cranial fossa had intracranial hemorrhage. There were 98 aneurysms in 81 patients with AVM-associated aneurysms. Eighty-nine (90.8%) ones underwent endovascular treatment, 6 (6.1%) patients with proximal aneurysms required microsurgery. Three distal aneurysms were not repaired. Thirty-four aneurysms were embolized with spirals. Embolization with spirals and balloon assistance was performed for 41 aneurysms, spirals with stent-assistance - for 9 aneurysms (including 1 distal MCA aneurysm in hemorrhagic period). Implantation of a flow-diverting stent was performed for 5 aneurysms (1 distal and 4 proximal aneurysms). There were 8 (8.9%) complications after embolization of 89 AVM-associated aneurysms (5 thromboembolic and 3 hemorrhagic events).

CONCLUSION

According to our data, intranidal aneurysms require exclusion of the parent AVM segment due to high risk of hemorrhage. Treatment of proximal AVM-associated aneurysms should be carried out prior to AVM embolization. Distal aneurysms do not regress after definitive AVM treatment and should be operated on after total AVM embolization.

An Update on Medications for Brain Arteriovenous Malformations

Despite a variety of treatment options for brain arteriovenous malformations (bAVMs), many lesions remain challenging to treat and present significant ongoing risk for hemorrhage. In Vitro investigations have recently led to a greater understanding of the formation, growth, and rupture of bAVMs. This has, in turn, led to the development of therapeutic targets for medications for bAVMs, some of which have begun testing in clinical trials in humans. These include bevacizumab, targeting the vascular endothelial growth factor driven angiogenic pathway; thalidomide or lenalidomide, targeting blood-brain barrier impairment; and doxycycline, targeting matrix metalloproteinase overexpression. A variety of other medications appear promising but either requires adaptation from other disease states or development from early bench studies into the clinical realm. This review aims to provide an overview of the current state of development of medications targeting bAVMs and to highlight their likely applications in the future.

Central nervous system vascular malformations: A clinical review

CNS vascular malformation is an umbrella term that encompasses a wide variety of pathologies, with a wide range of therapeutic and diagnostic importance. This range spans lesions with a risk of devastating neurological compromise to lesions with a slow, static or benign course. Advances in neurovascular imaging along with increased utilization of these advances, have resulted in more frequent identification of these lesions. In this article, we provide an overview on definitions and classifications of CNS vascular malformations and outline the etiologic, diagnostic, prognostic, and therapeutic features for each entity. This review covers intracranial and spinal cord vascular malformations and discusses syndromes associated with CNS vascular malformations.