Middle Cerebral Artery Pulsatility Is Highly Associated with Systemic Blood Viscosity in Acute Ischemic Stroke within 24 Hours of Symptom Onset

Background: Though blood viscosity (BV) is the major factor influencing pulsatility index (PI), it is unknown whether PI is related with BV in acute ischemic stroke. We explored the association between transcranial Doppler (TCD) PI and BV in acute ischemic stroke patient. Methods: Between January 2018 and December 2018, patients aged 40 years or older with an ischemic stroke or transient ischemic attack within 24 hours of symptom onset were recruited for the study. The scanning capillary-tube viscometer was used to assess whole blood viscosity. Doppler signals showing the highest mean flow velocity were used for PI calculation. Results: A total of 125 patients were enrolled for the study. The most frequent stroke subtype was lacunar stroke (42%), followed by stroke of undetermined etiology negative work-up (29%), and large artery atherosclerosis (19%). The mean middle cerebral artery (mMCA) PI was significantly associated with BV. Age, diabetes and BV were associated with mMCA PI, suggesting that increased mMCA PI is associated with old age, presence of diabetes, and increased BV. Conclusion: Pulsatility of MCA is highly associated with BV in acute ischemic stroke patient within 24 hours of symptom onset. Our findings indicate that TCD PI may be a useful non-invasive imaging modality for exploring the viscosity of cerebral vessels, which in turn is related to systemic BV.