Forty-eight studies were included in the review (10,327 patients): ten comparative studies, and 38 non-comparative studies. The study sample size ranged from 16 to 1,055 patients. The length of follow-up ranged from 0.1 to 6.7 years. The loss to follow-up ranged from 0 to 19.2%, where reported.
Transcatheter closure was associated with statistically significantly reduced risk of recurrent neurological events compared with medical therapy (RR 0.25, 95% CI 0.11 to 0.58; Ι²=66%; 10 studies). The pooled incidence of recurrent neurological events was 0.76 per 100 patient years (95% CI 0.48 to 1.05) for transcatheter closure and 4.39 per 100 patient years (95% CI 3.20 to 5.59) for medical therapy.
Subgroup analysis indicated that the risk of neurological events was lower with anticoagulants compared with antiplatelets (RR 0.58, 95% CI 0.41 to 0.82; 12 studies; Ι²=0%). The risk of recurrent neurological events was significantly lower with no residual shunt than shunt patients (OR 0.33, 95% CI 0.21 to 0.53; 17 studies).
Other results were presented in the review.
There was no evidence of publication bias with transcatheter closure studies, but there was evidence of bias with medical therapy studies.