New Data Demonstrate NovaGuide™ Intelligent Ultrasound Significantly Improves Detection of Right-to-Left Shunt

Clinical trial results show NovaGuide™ is three times more likely to detect RLS than transthoracic echocardiography
Data presented in late-breaking science session at International Stroke Conference 2022

LOS ANGELES, CA — February 11, 2022 — NovaSignal Corp., a medical technology and data company specializing in the assessment and management of brain health, today announced the results of a multi-center, prospective, single-arm study which show the autonomous NovaGuide™ Intelligent Ultrasound is three times more likely to detect right-to-left shunt (RLS) – a recognized risk factor for stroke – than standard of care transthoracic echocardiography (TTE). The study results were presented in a late-breaking science session at the American Heart Association 2022 International Stroke Conference, held in New Orleans, LA and virtually from February 9–11, 2022.

“Stroke care has advanced significantly in recent years, but those who have suffered a stroke have a high risk of recurrence,” said Robert Hamilton, Ph.D., Chief Scientific Officer and co-founder of NovaSignal. “RLS is a known risk factor for stroke and these study findings underscore the importance of utilizing NovaGuide as a diagnostic technology. It substantially improves detection of RLS compared to current standard of care. The results of this study suggest there may be many undiagnosed patients with RLS who are not receiving appropriate medical management with today’s diagnostic standards.”

The multi-center, prospective, single-arm BUBL clinical trial (NCT04604015) assessed use of NovaGuide compared to TTE for RLS diagnosis. The study enrolled adults (≥18 years) who presented with neurological signs and symptoms, which included embolic stroke or transient ischemic attack, on the differential diagnosis. The primary outcome was the percent shunt detection rate of NovaGuide relative to standard of care TTE. 

Among the 129 evaluable participants, RLS detection rate was 63.6% with NovaGuide (82 patients) and 20.9% by TTE (27 patients) for a difference of 42.6% (95% CI 28.6%-56.7%, p < 0.001). Additionally, NovaGuide accurately identified 35 patients (27%) with intervenable shunts (Spencer Logarithmic Scale ≥3), while TTE identified 13 (10%) of these cases for a difference of 17.1% (95% CI 6.9%-27.2%, p=0.002). The primary safety endpoint of adverse events with NovaGuide was 0% (95% CI 0%-2.8%).

“In the stroke population, RLS detection – especially due to a patent foramen ovale (PFO) – is important to reduce the risk of future stroke. We have known for decades that transcranial doppler (TCD) is exquisitely sensitive for RLS detection, but expertise is scarce. NovaGuide broadens the availability of TCD, allowing any provider to help their patients benefit from the sensitivity of TCD for RLS detection,” said principal investigator Mark N. Rubin, MD, RPNI, NVS, Medical Director of Neurosonology and Assistant Professor of Neurology at the University of Tennessee Health Science Center. “The BUBL study results underscore the potential for using this diagnostic capability to improve the management of ischemic stroke patients.”

Every year approximately 795,000 people in the U.S. have a stroke, with 23% of those occurring in people who have had a previous stroke.¹ RLS is a known risk factor for stroke as it provides a conduit for a venous clot to travel to the brain. A PFO, present in 25% of the population, is the most common source of RLS.²

About NovaSignal

Founded in 2013, NovaSignal Corp. is a medical technology company whose mission is to save lives by unlocking the power of cerebral blood flow data. The company’s FDA-cleared NovaGuide Intelligent Ultrasound combines non-invasive ultrasound, robotics, and artificial intelligence to assess cerebral hemodynamics in real time. Using cloud computing and data analytics, NovaSignal supports physicians in their clinical decision making in several neurological conditions including stroke, traumatic brain injury, and dementia. To learn more, visit


1. Tsao CW, Aday AW, Almarzooq ZI, Alonso A, Beaton AZ, Bittencourt MS, et al.; on behalf of the American Heart Association Council on Epidemiology and Prevention Statistics Committee and Stroke Statistics Subcommittee. Heart Disease and Stroke Statistics—2022 Update: A Report from the American Heart Association. Circulation. 2022; 145:e00–e00. doi: 10.1161/CIR.0000000000001052.

2. Ghosh AK, Jain A. Diagnosis and management of patent foramen ovale. Br J Hosp Med (Lond). 2015;76:C98–C102.

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