Abstract Number ‐ 17: Robot‐assisted transcranial Doppler versus transthoracic echocardiography for right to left shunt detection: Final Results

Abstract

Introduction Right to left shunt (RLS), including patent foramen ovale (PFO), is a recognized risk factor for stroke. RLS/PFO diagnosis is made by transthoracic echocardiography (TTE) which is insensitive, transesophageal echocardiography (TEE) which is invasive, and transcranial Doppler (TCD) which is noninvasive and accurate but scarce. Methods We conducted a multi‐center device clinical trial of robot‐assisted TCD (raTCD) versus TTE for RLS diagnosis in patients who presented with an event suspicious for embolic cerebrovascular ischemia. raTCD was performed with standard TCD bubble study technique. TTE bubble study was performed to local standards. The primary outcome was rate of RLS detection by raTCD versus TTE. Results 133 patients were enrolled (intention to treat, ITT) and 126 subjects had complete data. In the ITT cohort, mean age was 60 +/‐ 15 years, 46% were women, and 92% of qualifying events were diagnosed as ischemic stroke. raTCD was positive for RLS in 82 subjects (64%) and TTE was positive in 26 (20%) [absolute difference 43.4% (95% CI 34.3%‐52.5%), p < 0.001]. On prespecified secondary analysis, large RLS was detected by raTCD in 35 subjects (28%) vs 13 (10%) by TTE [absolute difference 17.5% (95% CI 10.1%‐24.8%), p < 0.001]. There were no serious adverse events. Conclusions raTCD was safe and 3 times more likely to diagnose RLS than TTE. TTE completely missed or underdiagnosed two thirds of large shunts diagnosed by raTCD. The raTCD device, used by health professionals with no prior TCD training, may allow providers to achieve the known sensitivity of TCD for RLS and PFO detection without the need for an experienced operator. TCD is the superior screen for RLS compared to TTE.