Transcranial Doppler findings in patients with COVID-19: a prospective observational study.

Abstract

Background: Transcranial Doppler (TCD) is a diagnostic tool to detect real-time spontaneous microembolic signals (MESs) in intracranial circulation. Critically-ill coronavirus disease 2019 (COVID-19) patients may present an increased likelihood of MESs due to systemic inflammation and hypercoagulability.

Objective: To assess the presence of MESs and other TCD parameters, including cerebral blood flow velocity (CBFV), pulsatility, and resistance indices, and to calculate the estimated cerebral perfusion pressure (eCPP) in patients with and without COVID-19.

Methods: The TCD monitoring was performed for 1 hour in both middle cerebral arteries (MCAs) of adult patients in the Intensive Care Unit (ICU) with confirmed COVID-19 infection. The eCPP was calculated by multiplying the mean arterial pressure (MAP) by the ratio of end-diastolic velocity to mean CBFV, then adding 14 mmHg.

Results: We evaluated 31 subjects: 11 intubated COVID-19 patients, 10 non-intubated COVID-19 patients, and 10 intubated non-COVID-19 patients. Patient ages ranged from 29 to 84 (median: 62; interquartile range [IQR]: 50-70) years, with 64.5% being male individuals. A total of 17 (54.8%) subjects died during hospitalization, and 2 patients (6.45%) lacked an ultrasonographic signal via the transtemporal window. No MESs were detected. A positive correlation was found between the resistance index of MCAs (p = 0.390) and D-dimer (p = 0.049). In contrast, direct bilirubin (p = -0.494), C-reactive protein (CRP; p = -0.540), activated partial thromboplastin time (aPTT; p = -0.495), and D-dimer (p = -0.439) were negatively correlated with eCPP.

Conclusion: No spontaneous cerebral microemboli were observed in this cohort, but patients with higher direct bilirubin, CRP, aPTT, and D-dimer presented lower eCPP.