Transcranial Doppler quantification of residual shunt after percutaneous patent foramen ovale closure. Comparison of two devices.

BACKGROUND: Recurrent paradoxical embolism after catheter-based closure of right-to-left shunt (RLS) can be related to residual RLS. To improve closure success, we need a better understanding of the anatomic and device-related factors associated with closure efficacy.
METHODS: Patients with cryptogenic neurologic events and severe RLS (Valsalva Spencer transcranial Doppler [TCD] grade 5/5+) who underwent patent foramen ovale (PFO) closure by either central pin (Amplatzer(®) PFO [A-PFO]) or central occluding (Amplatzer(®) SO [A-SO]) devices were evaluated for residual shunt by quantitative TCD evaluation at 3 months. The findings were correlated with atrial septal aneurysm (ASA), device type, and device size.
RESULTS: We closed 628 consecutive patients with either the A-PFO (n = 327) or A-SO (n = 301) device. The frequency of large defects, small defects, and ASA was 12%, 88%, and 44% of cases, respectively. Severe residual shunt was detected in 13% of A-PFO and 7% of A-SO recipients (P = 0.005). This difference was attributable to a much higher frequency of severe residual shunt among patients with large defects closed with the A-PFO compared to the A-SO device (12 out of 29 [41%] vs. 3 out of 42 [7%], respectively; P < 0.001). There was no significant difference in device failure frequency for small defects. The presence of ASA increased the frequency of severe residual shunt compared to those without this feature (36 out of 275 [13%] vs. 28 out of 353 [8%], respectively; P = 0.046) but did not influence device-related differences.
CONCLUSIONS: (1) Both noncentering and central occluding closure devices effectively reduce RLS after PFO closure. (2) Large PFO defects with or without ASA have lower residual shunt grades at 3 months when closed by central occluding devices. ©2010, Wiley Periodicals, Inc.