Right-to-Left Shunt Detection UsingTransf oraminal I nsonation of the Basilar Artery

摘要

Background and Purpose: Patent foramen ovale (PFO) screening in patients with cryptogenic stroke (CS) is warranted, as PFO closure in select CS patients is recommended for secondary stroke prevention. Transcranial Doppler (TCD) is non-invasive and has high sensitivity for PFO screening. 10% of the population has insufficient temporal bone windows to perform standard TCD monitoring of the middle cerebral arteries (MCA). We aimed to determine if transforaminal insonation of the basilar artery (TIBA) could be used for PFO screening in individuals unable to undergo standard TCD. Methods: We performed a retrospective, single-center, observational study of TIBA in patients with CS and inadequate temporal windows. We compared the PFO screening accuracy using TIBA versus echocardiogram, either transthoracic (TTE) or transesophageal (TEE). Results: Sixteen females and 4 males were included (mean age: 63.2 years). All patients underwent TTE, and 10 (50%) underwent gold-standard TEE. Nine patients had positive right-to-left shunt (RLS) with both TCD and echocardiogram. Two patients with negative echocardiogram had TCD-positive RLS. Three patients had RLS detected on echocardiogram, whereas TCD was negative. Six patients had absent RLS with both TCD and echocardiogram. The sensitivity and specificity of TIBA for RLS detection was 75%, positive predictive value 82% and negative predictive value 67%. Conclusion: PFO screening accuracy using TIBA was lower than standard transtem-poral insonation. Prospective evaluation of CS patients with TIBA and comparison to the gold-standard TEE should be performed to further guide clinical practice.