Left atrial pressure is associated with iatrogenic atrial septal defect after mitral valve clip

Mitral valve (MV) clip procedure requires interatrial trans-septal puncture to access the left atrium (LA). Iatrogenic atrial septal defect (iASD) is not uncommon and may remain for a while. However, haemodynamic and echocardiographic determinants of persistent iASD are not well investigated. We sought to find haemodynamic and echocardiographic determinants of iASD after MV clip.

A total of 131 patients with grades 3 to 4+ mitral regurgitation who underwent MitraClip and completed invasive haemodynamic measurement, baseline, 1 month and approximately 12 months of transthoracic echocardiography (TTE) follow-up were retrospectively reviewed.

TTE at 1 month showed persistent iASD in 57% (1M-iASD). Mean LA pressure after clip was significantly higher in patients with 1M-iASD than patients without 1M-iASD (17±6 mm Hg vs 15±5 mm Hg, p=0.01). Among patients with 1M-iASD, 24 patients (35%) had persistent iASD at 12 months (12M-iASD). Mean LA pressure after clip was significantly higher in patients with 12M-iASD than patients without 12M-iASD (19±6 mm Hg vs 16±6 mm Hg, p=0.04). Patients with 12M-iASD did not significantly differ from patients without 12M-iASD in terms of right heart enlargement, estimated systolic pulmonary artery pressure, New York Heart Association functional class and brain natriuretic peptide at 12 months. Logistic regression analysis, however, showed that mean LA pressure after clip was significantly associated with persistent iASD at 12 months in patients with 1M-iASD even after adjustment for cardiac index after clip and the prevalence of mitral regurgitation ≥3+ at 12 months (OR 1.10 per 1 mm Hg, 95% CI 1.01 to 1.21, p=0.04).

Elevated LA pressure after MV clip was associated with persistent iASD.