Is ICE the key to success?
Both the aforementioned approaches seem safe and feasible, although it has to be underlined that 3 patients (4.7%), all in the same cohort,7 had an inadvertent epicardial puncture during the transseptal access. In these 3 cases, although the device diameter ranged from 28 to 34 mm, a non-echocardiography guided TSP across the native interatrial septum (posteroinferior to the ASD closure device) was performed. After the epicardial puncture, 2 patients underwent TSP across the device in the same procedure, while in one case the procedure was rescheduled under transesophageal echocardiography (TEE) guidance. This percentage of epicardial puncture during a fluoroscopy-guided transseptal approach is extremely high (3 out of 9 patients), especially if we consider that procedures were performed in a high-volume center by skilled operators. As stated by Santangeli et al .6, intracardiac echocardiography (ICE) guidance is crucial to identify the portion of the native septum not covered by the ASD closure device (generally posteroinferior to the device), that should be preferentially targeted during TSP. In their cohort, if ICE failed to recognize a portion of the interatrial septum not covered by the device, mostly due to oversizing with respect to the interatrial septum or in cases with a device diameter ≥ 26mm, a direct puncture of the closure device was performed. Although Sang et al. 8 reported no procedural complications without ICE, suggesting that real-time monitoring of catheter movement may be sufficient to assess the optimal puncture site even when the device diameter is ≥ 26mm, in our opinion ICE guidance remains crucial to improve safety and to avoid unnecessary attempts to TSP by identifying unfavorable anatomies in which a straight puncture of the device should be performed. Real-time 3D-TEE has also shown to provide an accurate anatomic definition of the native septum during TSP11and may represent a valuable alternative, although ICE-guidance is corroborated by more robust data in this scenario and its use should be encouraged in routine practice.