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Right-to-left shunt detection via synchronized contrast transcranial Doppler combined with contrast transthoracic
Man-Juan Yao1,2, Ying-Ying Zhao3,4, Shui-Ping Deng3,4
1Department of Neurology, The First Affiliated Hospital of Shenzhen University, Shenzhen 518000, Guangdong Province, China.
Insights
Combining synchronized contrast transcranial Doppler (cTCD) and contrast transthoracic echocardiography (cTTE) improves the diagnosis of patent foramen ovale (PFO)-related right-to-left shunts (RLSs). This multimodal approach enhances accuracy for better patient outcomes.
Area of Science:
- Cardiology
- Neurology
- Medical Imaging
Background:
- Patent foramen ovale (PFO)-related right-to-left shunts (RLSs) are linked to cryptogenic stroke and migraines.
- Individual use of contrast transcranial Doppler (cTCD) and contrast transthoracic echocardiography (cTTE) can lead to false-negative results in RLS detection.
- Existing literature shows gaps in understanding the limitations of cTCD and cTTE, with conflicting recommendations and inefficient testing protocols.
Purpose of the Study:
- To evaluate the diagnostic accuracy of multimodal ultrasound in detecting PFO-related RLSs.
- To assess the efficiency of synchronized cTCD and cTTE for improved RLS diagnosis.
Main Methods:
- Prospective enrollment of four patients with cryptogenic stroke, migraines, or unexplained dizziness.
- Synchronized testing using both cTCD and cTTE.
- 24-month follow-up period for monitoring patient outcomes.
Main Results:
- cTTE identified moderate to large RLSs in stroke and migraine patients, while cTCD detected only small RLSs.
- Combined cTTE and cTCD confirmed moderate and large RLSs, leading to successful PFO occlusion in two patients with no recurrence of symptoms.
- In two other patients, discrepancies between cTTE and cTCD findings (small vs. large RLS) were noted, and these patients, without intervention, experienced symptom recurrence.
Conclusions:
- Exclusive reliance on cTTE or cTCD may underestimate RLS severity, impacting risk assessment.
- Synchronized multimodal ultrasound (cTCD with cTTE) enhances diagnostic accuracy for PFO-related RLSs.
- This combined approach aids in making better diagnostic and therapeutic decisions for patients.
Background:
Patent foramen ovale (PFO)-related right-to-left shunts (RLSs) have been implicated in cryptogenic stroke and migraine, with larger shunts posing a higher risk. When used individually to detect RLS, contrast transcranial Doppler (cTCD) and contrast transthoracic echocardiography (cTTE) may yield false-negative results. Further, the literature exposes gaps regarding the understanding of the limitations of cTCD and cTTE, presents conflicting recommendations on their exclusive use, and highlights inefficiencies associated with nonsynchronous testing.
Aim:
To investigate the accuracy of multimodal ultrasound to improve diagnostic efficiency in detecting PFO-related RLSs.
Methods:
We prospectively enrolled four patients with cryptogenic stroke (n = 1), migraine (n = 2), and unexplained dizziness (n = 1) who underwent synchronized cTCD combined with cTTE. The participants were monitored and followed-up for 24 months.
Results:
cTTE identified moderate and large RLSs in patients with recurrent cryptogenic stroke and migraines, whereas cTCD revealed only small RLSs. Moderate and large RLS were confirmed on combined cTTE and cTCD. After excluding other causes, both patients underwent PFO occlusion. At 21- and 24-month follow-up examinations, neither stroke nor migraine had recurred. cTTE revealed a small RLS in a third patient with unexplained dizziness and a fourth patient with migraines; however, simultaneous cTCD detected a large RLS. These patients did not undergo interventional occlusion, and dizziness and headache recurred at the 17- and 24-month follow-up examinations.
Conclusion:
Using cTTE or cTCD may underestimate RLS, impairing risk assessments. Combining synchronized cTCD with cTTE could enhance testing accuracy and support better diagnostic and therapeutic decisions.
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