Abstract WP261: Role of Transcranial Doppler in a New Era of Patent Foramen Ovale Closure

Introduction: Recent patent foramen ovale (PFO) closure trials have demonstrated efficacy in secondary stroke prevention. Transcranial Doppler (TCD) can reliably detect the presence of PFO, with sensitivity comparable to echocardiography. We sought to compare the sensitivity of TCD in detecting right to left shunt (RLS) using transesophageal echocardiogram (TEE) criteria as described in the CLOSE and REDUCE trials. Methods: We retrospectively reviewed all TCD studies at our institution who also had TEE studies. We excluded patients who had their PFO closed prior to one of these studies being performed. We classified the size of the PFO based on both REDUCE and CLOSE criteria (large was defined as greater than 25 microbubbles and greater than 30 microbubbles, respectively) and compared to the size based on the Spencer grade. Results: A total of 525 TCD bubble studies were performed at our institution from May 2013 to June 2018, 220 of which also underwent TEE. Using TEE as the gold standard, TCD detected 97.61% (41/42) of any moderate-large RLS and 100% (10/10) of any large RLS. The single patient who had a moderate RLS on TEE, but not TCD had a poor Valsalva during the TCD study. TCD detected 33 patients with RLS not detected on TEE [33% (33/100)], 33.3% of which were considered significant (Spencer grades 3-5). Conclusion: TCD is comparable to TEE in detecting moderate-to-large RLS based on REDUCE/CLOSE criteria. TCD detected an appreciable amount of RLS (a third of which were Spencer grades 3-5) not detected by TEE. Further study is needed to clarify the role of PFO closure in patients with significant RLS on TCD, but no RLS on TEE. TCD is a good alternative screening tool for RLS as compared with TEE methods from recent positive trials.