P1857Risk calculator for prediction of iatrogenic atrial septal defect persistence following percutaneous mitral valve repair

Abstract Background The rising number of new percutaneous interventions for left-sided heart disease leads to increased occurrence of iatrogenic atrial septal defect (iASD). The percutaneous mitral valve repair (PMVR) for severe, symptomatic mitral regurgitation (MR) also requires intraprocedural puncture of the interatrial septum. In some cases iASD is persisting and becomes haemodynamically relevant with enhanced right heart overload due to significant left-to-right-shunting. Purpose This study aimed to evaluate pre- and periprocedural factors that may favour persistence and haemodynamic relevance of iASD in patients after PMVR. Methods In 2015, 75 consecutive patients with severe MR (age 74.8±10.5y) and following PMVR were enrolled. After 12 months, 57 patients completed their follow up (FU) including clinical conditions, transthoracic echocardiography (TTE), and cardiovascular magnetic resonance (CMR) whenever feasible. We evaluated the impact of comorbidities as well as intraprocedural, haemodynamic and functional characteristics that may favour persistence of iASD by multivariate analysis. Haemodynamic relevance of iASD was defined as right heart overload with predominantly significant enlargement of the right atrium (RA), impairment of right heart function as defined by fractional area shortening (FAC), and ratio of pulmonary to systemic blood flow (Qp/Qs>1) when available. Results 18 out of 57 patients (32%) showed a persistent iASD (+iASD), being associated with a specific combination of comorbidities as well as pre-procedural and periprocedural factors that can be summarised by a multifactorial iASD risk calculator (+iASD vs. -iASD: 6.3±2.9 vs. 3.9±2.7; p=0.0058). 11 iASD (61%) became haemodynamically relevant (+hd iASD) with a significant right heart overload (RA area +hd iASD vs. -hd iASD: baseline 23.1±4.1 vs. 23.2±4.3; FU 30.7±6.3 vs. 20.1±4.6; p