Transcatheter Closure of ASD
abstract & commentary
Synopsis: Centrally located ASDs and PFOs associated with cerebral emboli can be successfully treated with the double-umbrella-style atrial septal defect occluder system with acceptable morbidity.
Source: Sievert H, et al. Am J Cardiol 1998;82: 1405-1413.
The european trial of the double-umbrella-style atrial septal defect (ASD) occluder system has reported the feasibility, safety, and efficacy of this system in 154 patients with ASD and 46 with patent foramen ovale (PFO) who had cerebral embolism presumed to be paradoxic. The placement of the two umbrellas requires femoral venous and arterial access, a minimal patient weight of 10 kg, heparinization, and a transesophageal echo to guide seating of the umbrellas. The 200 patients ranged in age from 1 to 74 years (mean 32) and 138 were adults. Total procedure time was 2-3 hours, with mean fluoroscopy times of 30-45 minutes, and the average ASD diameter was about 15 mm. The procedure was unsuccessful in 26 patients (13%); in 20 patients, the device could be brought out by the catheter system, but six required surgery for retrieval because of device embolization in two, atrial wall perforation in two, entrapment in the Chiari network in one, and frame fracture in one. Of the 20 patients with unsuccessful deployment and successful retrieval, almost all had ASD greater than 20 mm in diameter and small septal rims to attach the device. Eleven additional patients had surgery for device removal during follow-up because of complications or large residual shunts. The remaining 163 patients (81%) were followed for 6-36 months (mean 17). Total (initial and follow-up) complications included residual shunt in up to one-third of patients, two cerebral embolic episodes despite evidence of thrombus on transesophagael echo at two weeks in 6% of patients, pericardial effusion in six, atrial perforation in five, infectious endocarditis in two, and device fracture in 23 (14%). Sievert and colleagues conclude that centrally located ASDs and PFOs associated with cerebral emboli can be successfully treated with this device with acceptable morbidity.
Comment by Michael H. Crawford, MD
Unfortunately, this report is not sufficiently detailed to ascertain when each complication occurred and what the clinical outcome was. In the discussion, Sievert et al state that the rate of complete defect closure was 63%, but only 8% of the remaining 37% had significant residual shunts. However, we do not know how many of the successfully closed patients were ASD vs. PFO. Regardless, this does not compare well to the surgical results of significant residual shunts in the range of 2-8%. Surgical series have shown some mortality (0-3%) and morbidity (8-15%) but they were mainly attributable to patients with pulmonary hypertension and other cardiac lesions. In those without these conditions, long-term surgical outcomes have been excellent. Further follow-up will be necessary to judge the efficacy of this device, especially with regard to long-term device fracture.
This device seems best suited for patients with PFOs or small ASDs where there is sufficient septal tissue to anchor the umbrellas. Also, anticoagulation may be necessary for three months or so until the device is endothelialized. In addition, more stringent aseptic techniques than are usually used in the catheterization laboratory may be necessary to prevent infection. Finally, the issue of chronic antibiotic prophylaxis is raised by the one patient who developed device endocarditis six months after implantation. Clearly, progress is being made with transcatheter device ASD/PFO closure and we now have an alternative for the patient in whom surgery is not feasible. However, surgery is still the treatment of choice at this time.
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