Detection rate and shunt grading with synchronous testing of contrast transcranial Doppler and contrast transthoracic echocardiography: Preliminary findings

Patent foramen ovale, a common congenital atrial septal defect, may lead to cardiac right-to-left shunting (RLS), which has been associated with various diseases. Reliable techniques for detecting RLS are essential for diagnosis and assist with treatment decision-making. Contrast transcranial Doppler (c-TCD), contrast transthoracic echocardiography (c-TTE), and contrast transesophageal echocardiography can be used to detect RLS. However, it is still unclear which ultrasound modalities are the most practical and cost-effective. To evaluate the efficacy of synchronous c-TCD and c-TTE in detecting cardiac RLS. We prospectively designed and continuously recruited 100 patients with cryptogenic stroke, migraines, transient ischemic attack, unexplained syncope, or dizziness admitted at the First Affiliated Hospital of Shenzhen University between February 2020 and August 2020. Ninety-five patients underwent synchronous c-TCD and c-TTE (during a single contrast-enhanced ultrasound session). We compared synchronous test results with the results of c-TCD alone and c-TTE alone. Ninety-five patients successfully underwent synchronous c-TCD and c-TTE, with the data analyzed for each individual. The positive detection rates of Grade I, II, and III shunts with synchronous c-TCD and c-TTE were higher than those with c-TTE or c-TCD alone (P = .047, P = .002, and P = .024, respectively). Overall, the positive detection rates of synchronous tests, c-TCD alone, and c-TTE were 69.5%, 51.6%, and 31.6%, respectively (P = .000, and P = .012). Among the 66 patients who were double-RLS-positive (both c-TTE and c-TCD showed positive results), as detected by the synchronous test, 26 (39.3%) patients who underwent c-TTE alone had higher shunt grades detected than those who underwent c-TCD alone. Conversely, 5 (7.6%) patients who underwent c-TCD alone had higher shunt grades detected than those who underwent c-TTE alone (P = .000). Synchronous c-TCD and c-TTE testing can significantly improve the detection rate, accuracy, and test process efficacy for quantifying RLS, and reduce the testing risk, workload, and medical costs.