Time-course of cardiac remodeling following transcatheter closure of atrial septal defect.

BACKGROUND: Right chamber dilatation and right-to-left volumetric unbalance are well-known cardiac consequences of atrial septal defect (ASD) shunt, accounting for most of its long-term complications. Thus, cardiac volumetric unloading is a major aim of ASD closure. Different from surgery, transcatheter option might be considered as an "unbiased" tool to evaluate the cardiac geometric remodeling following ASD closure.

METHODS: Extent and time-course of cardiac geometric changes were assessed by echocardiography 24 h, 1 and 6 months after percutaneous closure of large ASD (mean diameter 17+/-6 mm, QP/QS 2.2+/-0.9) in 42 asymptomatic patients (age 22+/-18 years).

RESULTS: Transcatheter closure was accomplished using the Amplatzer Septal Occluder device (mean 23+/-7 mm, median 24 mm), achieving a complete occlusion in all patients at the 6-month follow-up control. After ASD closure, right atrial (RA) volume reduced from 45+/-24 to 28+/-12 ml (-37.8%, p<0.001), while left atrial (LA) volume did not significantly change. Inlet and infundibulum right ventricular (RV) end-diastolic diameters reduced by 23+/-2% and 23+/-3%, respectively (p<0.001 for both measurements), although with a different time-course of changes. Finally, transverse left ventricular (LV) end-diastolic diameter increased from 39+/-7 to 44+/-5 mm (+11.4%, p<0.01). These geometric changes resulted in an RV/LV diameter ratio decrease by 34+/-3% (p<0.001). Nearly 90% of cardiac remodeling ensued within 1 month from shunt disappearance (50% within 24 h).

CONCLUSIONS: Percutaneous ASD closure results in early and striking cardiac geometric changes that almost completely revert the right-to-left volumetric unbalance. Most of this geometric remodeling ensues within a few weeks from ASD closure.