What evidence indicates that device closure may benefit patients with high-risk anatomic features? 
There is evidence that patients with high-risk anatomic features, including larger shunt size (defined variably), particularly an atrial septal aneurysm, are more likely to benefit from device closure. This is supported by an individual patient level meta-analysis of the first 3 trials552 which found slightly greater benefit among patients with these characteristics, as well as the RESPECT trial which showed significant interactions between treatment and both larger shunt size (>20 micro-bubbles) and atrial septal aneurysm, with benefit shown only when either was present. 