Oral anticoagulants or antiplatelets for cryptogenic stroke: a systematic review and meta-analysis

Abstract Background Cryptogenic strokes comprise 20 to 30% of ischemic strokes and include a substantial proportion classified as embolic stroke of undetermined source (ESUS). However, the optimal antithrombotic strategy for cryptogenic stroke remains contentious. Purpose We conducted a systematic review and meta-analysis to compare the efficacy and safety of oral anticoagulants (OAC) versus antiplatelets in patients with cryptogenic stroke. Methods Six electronic databases of PubMed, Embase, Web of Science, the Cochrane Library, Google Scholar and ClinicalTrials.gov were searched from inception to Feb 15, 2024 to identify relevant randomized controlled trials (RCTs) comparing stroke recurrence and major bleeding rates between OAC and antiplatelets in cryptogenic stroke patients. We included trials adhering to a stringent diagnostic work-up for cryptogenic stroke, defined as cerebral infarction not attributed to definite sources of cardioembolism, large artery atherosclerosis, or small artery disease despite undergoing comprehensive investigations. The primary outcome was recurrent ischemic stroke, and the secondary outcome was major bleeding based on International Society of Thrombosis and Hemostasis criteria. Subgroup analysis was conducted for ESUS patients with an increased risk of cardiac emboli, such as patent foramen ovale (PFO) and atrial cardiopathy, defined as lead V1 terminal P-wave > 5000 μV × ms in electrocardiogram, serum N-terminal pro-B-type natriuretic peptide level > 250 pg/mL, and left atrial diameter (LAE) > 4 cm, or LAE index ≥ 3 cm/m2 on echocardiogram. Hazard ratio (HR) with 95% confidence (CI) was used as a measure of the effect estimates for aforementioned outcomes. Random-effects meta-analysis was performed using a restricted maximum likelihood model given between-study variance is inevitable. Results Our meta-analysis included 9 RCTs with a total of 15,139 patients (OAC = 7,343; antiplatelets = 7,796). ARCADIA, RE-SPECT ESUS, and NAVIGATE ESUS Trial investigated apixaban, dabigatran, and rivaroxaban, respectively, while warfarin was primarily used as OAC in the remaining six trials. Aspirin was predominantly utilized for antiplatelet therapy. There was no significant difference in recurrent ischemic stroke between OAC and antiplatelets (HR, 0.90; 95% CI, 0.78 to 1.04; I2 = 0%). However, OAC use was associated with a significantly higher risk of major bleeding (HR, 1.66; 95% CI, 1.07 to 2.56; I2 = 36%). Subgroup analysis in ESUS patients revealed comparable rates of recurrent ischemic stroke in those with atrial cardiopathy (HR, 0.91; 95% CI, 0.65 to 1.29; I2 = 0%) and PFO (HR, 0.72; 95% CI, 0.49 to 1.07; I2 = 0%). Conclusions Our meta-analysis suggests that OAC use does not decrease the risk of recurrent ischemic stroke compared with antiplatelet use but is associated with a significantly higher risk of major bleeding in patients with cryptogenic stroke.Primary (A) and secondary (B) outcomesSubgroup analysis for recurrent stroke