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Updated: Jun 24, 2026
Functional Transcranial Doppler Ultrasound for Monitoring Cerebral Blood Flow
Published on: March 15, 2021
Cerebral Hemodynamic Reserve Abnormalities Detected Via Transcranial Doppler Ultrasound in Recovered COVID-19
Anselmo Antonio Abdo-Cuza1, Charles Hall-Smith1, Juliette Suárez-López2
1Medical-Surgical Research Center (CIMEQ), Havana, Cuba.
Insights
Recovered COVID-19 patients exhibit reduced cerebral hemodynamic reserve and breath-holding index, indicating potential long-term vascular effects. Transcranial Doppler ultrasound may aid in evaluating these persistent changes post-SARS-CoV-2 infection.
Area of Science:
- Neurology
- Vascular Medicine
- Infectious Diseases
Background:
- COVID-19 (SARS-CoV-2) can cause endothelial injury and microvascular damage, contributing to multiorgan failure.
- Cerebrovascular endothelial damage in COVID-19 increases stroke risk, necessitating prompt diagnosis.
- Transcranial Doppler ultrasound can assess cerebral hemodynamic reserve, but its use in COVID-19 follow-up is limited.
Purpose of the Study:
- To estimate baseline cerebral hemodynamic patterns in recovered COVID-19 patients.
- To evaluate cerebral hemodynamic reserve and breath-holding index in individuals post-SARS-CoV-2 infection.
- To compare hemodynamic reserve between recovered COVID-19 patients and a control group.
Main Methods:
- An exploratory study involving 51 participants (25 recovered COVID-19 patients, 26 controls).
- Participants were assessed using transcranial Doppler ultrasound for baseline and post-apnea cerebral hemodynamic patterns.
- Recovered patients were categorized by disease severity (asymptomatic/mild vs. severe/critical).
Main Results:
- No significant differences in baseline cerebral hemodynamics were observed between groups.
- Recovered COVID-19 patients showed significantly lower cerebral hemodynamic reserve and breath-holding index compared to controls.
- These hemodynamic deficits were consistent across different COVID-19 disease severity levels.
Conclusions:
- SARS-CoV-2 infection is associated with decreased cerebral hemodynamic reserve and breath-holding index, persisting after recovery.
- These findings suggest potential endothelial damage as a mechanism, irrespective of initial disease severity or neurological symptoms.
- Integrating transcranial Doppler ultrasound into COVID-19 evaluation and follow-up protocols is recommended.
Introduction:
SARS-CoV-2 infection can produce endothelial injury and microvascular damage, one cause of the multiorgan failure associated with COVID-19. Cerebrovascular endothelial damage increases the risk of stroke in COVID-19 patients, which makes prompt diagnosis important. Endothelial dysfunction can be evaluated by using transcranial Doppler ultrasound to study cerebral hemodynamic reserve, but there are few of these studies in patients with COVID-19, and the technique is not included in COVID-19 action and follow-up guidelines nationally or internationally.
Objective:
Estimate baseline cerebral hemodynamic patterns, cerebral hemodynamic reserve, and breath-holding index in recovered COVID-19 patients.
Method:
We conducted an exploratory study in 51 people; 27 men and 24 women 20-78 years of age, divided into two groups. One group comprised 25 recovered COVID-19 patients, following clinical and epidemiological discharge, who suffered differing degrees of disease severity, and who had no neurological symptoms or disease at the time they were incorporated into the study. The second group comprised 26 people who had not been diagnosed with COVID-19 and who tested negative by RT-PCR at the time of study enrollment. Recovered patients were further divided into two groups: those who had been asymptomatic or had mild disease, and those who had severe or critical disease. We performed transcranial Doppler ultrasounds to obtain baseline and post-apnea tests of cerebral hemodynamic patterns to evaluate cerebral hemodynamic reserve and breath-holding indices. We characterized the recovered patient group and the control group through simple descriptive statistics (means and standard deviations).
Results:
There were no measurable differences in baseline cerebral hemodynamics between the groups. However, cerebral hemodynamic reserve and breath-holding index were lower in those who had COVID-19 than among control participants (19.9% vs. 36.8% and 0.7 vs. 1.2 respectively). These variables were similar for patients who had asymptomatic or mild disease (19.9% vs.19.8%) and for those who had severe or critical disease (0.7 vs. 0.7).
Conclusions:
Patients recovered from SARS-CoV-2 infection showed decreased cerebral hemodynamic reserve and breath-holding index regardless of the disease's clinical severity or presence of neurological symptoms. These abnormalities may be associated with endothelial damage caused by COVID-19. It would be useful to include transcranial Doppler ultrasound in evaluation and follow-up protocols for patients with COVID-19.
