Abstract W P204: Diagnostic Ability of a Novel Probe Attached to the Cervix for the Detection of Right-to-left Shunt Is Similar to Transesophageal Echocardiography

Introduction: Although transcranial Doppler (TCD) plays an important role of detecting right-to-left shunt (RLS) in order to diagnose patients as a paradoxical brain embolism, insufficient temporal bone window interrupts the precise examination. So, we developed the novel probe (PSUP) attached to the cervix for the detection of RLS. Our hypothesis is that diagnostic accuracy of RLS by PSUP is comparable to those of transesophageal echocardiography (TEE) as a gold standard. . Methods: Subjects were patients with ischemic stroke and transient ischemic attack who underwent TEE. PSUP was a 2.0-MHz center frequency and had an equal property with TCD transducer. The shape was thin, soft, and square modified for adequate attachment to the neck. At first, we performed TEE with the echoscope at the level of the fossa ovalis after injection of saline agitated with air in the right antecubital vein. The procedure was performed with and without Valsalva maneuver. Visualization of microembolic signals (MES) induced contrast agent within the right atrium and crossing the interatrial septum was considered positive for RLS. Then, monitoring using PSUP was performed at unilateral common carotid artery (CCA) using similar preparation and procedure to TEE. RLS by PSUP was diagnosed as having 1and more MES in CCA. After compared RLS detectable rate between TEE and PSUP, accuracy parameters for RLS detection of PSUP against TEE were calculated. Results: From May to August 2014, 21 patients were included in this study. RLS was 5 (24%) of 21 on TEE, and 5 (24%) on PSUP, respectively (table). As a reference of TEE findings, diagnostic power of PSUP was 84% of sensitivity, 94% of specificity, 84% of positive predictive value, 94% of negative predictive value, and 91% of accuracy. Conclusion: RLS detection by PSUP is substantially correct. PSUP may be useful for patients with insufficient temporal bone window, such as elder Asian women.