To use or not to use antithrombotics in unruptured cerebrovascular malformations? A systematic review focusing on this clinical and surgical dilemma

OBJECTIVE Antithrombotic medications (ATMs), including antiplatelet therapy (APT) and oral anticoagulants (OACs), are widely used in current clinical practice for the prevention and treatment of a variety of cardiovascular diseases, deep vein thrombosis, and pulmonary thromboembolisms. The long-term usage of these drugs, associated with an inherent risk of bleeding, raises concerns for unruptured cerebrovascular malformations (UCVMs), such as arteriovenous malformations (AVMs), cerebral cavernous malformations (CCMs), and intracranial aneurysms (IAs), in which the bleeding risk also poses a major threat. The aim of this study was to assess the safety and risk-benefit ratio of ATMs in these various neurosurgical diseases and to give neurosurgeons a safe and reasonable choice regarding whether to administer ATMs to these patients during the course of the disease. METHODS The authors conducted a systematic review of the literature (PubMed/MEDLINE and Embase) according to Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols (PRISMA-P) guidelines, which yielded 4 papers about CCMs, 2 about AVMs, and 9 about IAs. The risk of bias was assessed using the Cochrane Collaboration's tool. RESULTS For AVMs, only 2 studies with a total of only 14 patients were included. Data on AVMs and ATMs are limited and weak, relying on small case series. Nevertheless, there is no evidence for either an increased risk of intracranial hemorrhage in patients with AVMs who are receiving ATMS or the need to interrupt ATMs in those patients who have been diagnosed with sporadic, unruptured brain AVMs. With respect to CCMs, the literature search resulted in 4 cohort studies and 1 meta-analysis. These studies affirmed the absence of a correlation between ATMs and an increased risk of CCM bleeding while simultaneously suggesting a protective role of ATMs against bleeding. Concerning IAs, the topic is more complex and debated, despite larger case series on IAs than on AVMs or CCMs. The benefits of ATMs for IAs may vary according to the type of intervention and specific drug administered. Evidence supports the continuation of long-term APT for all patients newly diagnosed with an IA, whereas starting APT in patients with incidentally discovered IA as a means of prophylaxis against rupture is unclear. CONCLUSIONS The findings of this review should be taken as a wide overview of UCVM and ATM. Future research should consider the relationship of AVM, CCM, and IA with APT and OAC independently. https://thejns.org/doi/abs/10.3171/2023.7.FOCUS23117