Long-term impact of transcatheter atrial septal defect closure in adults on cardiac function and exercise capacity.

Background: The long-term impact of transcatheter atrial septal defect (ASD) closure on right ventricular (RV) remodeling and exercise capacity is unknown.

Methods: We studied with cardiopulmonary exercise testing and transthoracic echocardiography 29 adults (age 42.3+/-16.4 years) with hemodynamically significant ASD just before transcatheter defect closure and after 6 and >36 months from closure.

Results: Compared to 6 months after closure, a further improvement of peak oxygen uptake (p<0.001) and of the slope of ventilation/carbon dioxide production (p<0.001) was observed 3 years after the procedure, so that peak oxygen uptake appeared to be within the normal range in 23/29 patients (79%). Right ventricular short-axis (p<0.05) and long-axis (p<0.05) diameters further decreased beyond the 6-month period. The long-term improvement in exercise capacity correlated with pulmonary-to-systemic flow ratio (R=0.55, p=0.003) and with percentage decrease in RV short-axis diameter (R=0.59, p=0.002), but it did not correlate with age at closure (R=0.25, p=0.46). All patients who did not achieve a normal exercise capacity after 3 years from closure had a severely depressed pre-closure peak oxygen uptake (<50% of predicted).

Conclusions: Adults who undergo transcatheter ASD closure may experience a further improvement in exercise capacity in the long term. The long-term improvement in exercise capacity is associated to an improvement in cardiac form and function and is not influenced by age at closure. Even if the majority of patients may reach a normal exercise capacity after ASD closure, an abnormal exercise capacity may persist in those patients that had a peak oxygen uptake below 50% of predicted value before the procedure.