[The morphologic changes of Amplatzer asymmetric ventricular septal defect occluder after transcatheter closure of perimembrane ventricular septal defect].

Objective: Catheter closure of perimembrane ventricular septal defect (PMVSD) using the Amplatzer asymmetric ventricular septal defect occluder (AAVSDO) is a potential alternative for open surgical repair. However, the profile of the device obtained after closure probably continues to change some concerns regarding its safety. This study was designed to evaluate the morphologic changes of AAVSDO by transthoracic echocardiography examination (TTE) and X-ray examination after transcatheter closure of PMVSD.

Methods: A total of 23 patients, aged 2.5 - 47.0 years, with PMVSDs underwent transcatheter closure with the AAVSDO. Each patient underwent TTE and X-ray examination with same radiography system immediately, 72 hours, 6 months and 1 year after the transcatheter closure procedures, respectively. Seven parameters were measured by TTE and X-ray to evaluate the morphologic changes of AAVSDO: the distance between superior edge of left disk of AAVSDO and aortic valve (L(1)), the distance between superior extremity edge of two disks of the occluder (L(2)), the distance between inferior extremity edge of two disks of the occluder (L(3)), the distance between two marks on the left and right disks (L(4)), the diameter of left disk (D(1)), the diameter of left disk (D(2)), and the degree of angle between left and right disks (alpha). In the meantime, the influences of occluder's morphologic changes were evaluated by TTE.

Results: The PMVSD diameter ranged from (8.53 +/- 4.82) mm (3.91 - 17.0 mm). The device diameter ranged from 6 - 18 (10.34 +/- 7.16) mm. AAVSDO was performed successfully in all the 23 patients who underwent immediately, 72 hours and 6 months follow-up after catheter closure, and 12 patients accomplished 1-year follow-up. L(2), L(4) and alpha were shorter at 6-months than 72-hours after procedures, but D(1) and D(2) were greater at 6-months than 72-hours after procedures in all patients. Alpha was decreased further 1 year after the procedure, but other parameters did not change significantly compared with those at 6-months after procedures. The lower profile and smaller thickness of AAVSDO were observed in the follow-up. Meanwhile, D(1) and D(2) changed significantly during the follow-up. L(4) had a weak positive correlation with device size (r = 0.47, 0.33 and 0.39, respectively) and with alpha (r = 0.47, 0.53 and 0.49, respectively), and had weak negative correlation with D1 (r = -0.27, -0.45 and -0.29, respectively). After deployment of the prosthesis there was no residual shunt in 20 of 23 patients (87%). There was a trivial residual shunt that disappeared at the six month follow up in two patients, and a small residual shunt that disappeared at the one year follow up in one patient. The morphologic changes of AAVSDO did not influence the structure near PMVSD.

Conclusion: The morphologic changes of Amplatzer occluder were observed in the follow-up. The change of the occluder was safe and beneficial to improve short-term curative effect.