Abstract 4684: Differences in Baseline Features and Long Term Follow-Up Post-Transcatheter Closure in Patients with Secundum Atrial Septal Defect - A Cohort Study

Patients with atrial septal defects (ASD) may develop pulmonary arterial hypertension (PAH). We aimed to explore predictors of PAH and characterize the evolution of pulmonary arterial systolic pressures (PASP) after transcatheter ASD closure. A cohort study was performed on 215 consecutive patients who underwent attempted transcatheter ASD closure, of which 194 were successful. Patients were classified into 4 groups based on PAH severity derived from baseline echocardiographic PASP estimates: no PAH (<40mmHg; Group I, n=107), mild PAH (40 –50mmHg; Group 2, n=62), moderate PAH (50 – 60mmHg; Group 3, n=27), and severe PAH (≥60mmHg; Group 4, n=19). Follow-up echocardiography was performed at a median of 10 months (IQR 3, 25 months). Independent predictors of moderate or severe baseline PAH were older age (OR 1.10 per year, p<0.0001), larger ASD size (OR 1.13 per mm, p=0.0052), female gender (OR 3.9, p=0.0313) and moderate or severe tricuspid regurgitation (OR 3.6, p=0.0043). Post closure, baseline PAH severity was associated with a greater likelihood of a ≥5mmHg reduction in PASP (33.7%, 73.9%, 79.2%, 100.0%, in Groups 1 to 4, p <0.0001) and larger reduction in PASP (median reduction 0, 8, 17, 22 mmHg in Groups 1 to 4, p<0.0001). However, likelihood of normalization of PASP (<40mmHg) was inversely correlated with baseline PAH severity (90.2%, 71.7%, 66.7%, 23.5% for Groups 1 to 4, p<0.0001). Higher baseline PASP (OR 1.20 per mmHg, p<0.0001), younger age (OR 0.97, p=0.0202), and smaller body surface area (OR 0.13 per m 2 , p=0.0210) independently predicted a ≥5mmHg reduction in PASP. Among patients with moderate or severe baseline PAH, normalization of PASP occurred in 48.8%, and was independently predicted by a lower baseline PASP (OR 0.91 per mmHg, p=0.0418) and absence of moderate or severe tricuspid regurgitation preceding ASD closure (OR 0.139, p=0.0420). In patients with ASD, severity of PAH is modulated by age, gender, defect size, and presence of moderate or severe tricuspid regurgitation. Patients with moderate or severe PAH benefit from a substantial reduction in PASP post-transcatheter ASD closure, but PASP remains elevated in a sizeable proportion of patients, warranting close long-term follow-up.