Limitations
RV distension, volume overload
VOLUME OVERLOAD
The sample size, especially those of the spontaneous closure cohort, is rather small and the conclusions drawn should be seen as hypothesis generating, as statistical power is lacking to exclude effects not observed. The shunt fraction of 30% has been proposed as a cut-off to balance the risk of RV distension due to volume overload to the benefit of alleviating left atrial pressure by an intentionally created ASD in patients with HF and was therefore chosen as inclusion criterion in the randomized MITHRAS trial [