Patterns of transcranial doppler flow velocities in recent ischemic stroke patients

Abstract

Context: Intracranial atherosclerosis is a common cause of stroke in India. Transcranial Doppler (TCD) provides a noninvasive way to study basal intracranial blood vessels. The Oxfordshire Community Stroke Project (OCSP) classification is a simple clinical stroke classification system that has prognostic significance and has been associated with size and location of the infarct. Aim: This study was undertaken to identify patterns of TCD abnormalities in our stroke population particularly in relation to the OCSP classification. Setting and Design: A cross-sectional study was conducted at a tertiary care center in South India. Methods: Recent nondisabling ischemic stroke patients were studied. TCD was used to insonate bilateral middle cerebral, bilateral anterior cerebral, bilateral vertebral, and basilar arteries. Mean flow velocity was used to define normal or abnormal flow as per standard criteria. Statistical Methods: Association between abnormal flow velocities and OCSP classification was studied using Chi-square tests. Univariate and multivariate analysis was performed to determine factors associated with abnormal flow velocities. Results: Of the 59 participants studied, 42 (71%; 95% confidence interval [CI]: 57.3-84.7%) had abnormal flow velocities in one or more vessels and this was significantly associated with smoking (odds ratio = 5; 95% CI: 1.2–21.8). All abnormal flow velocities were blunted flow velocities. Anterior circulation flow velocity abnormalities were seen among all OCSP stroke subtypes, but posterior circulation flow abnormalities were associated with posterior circulation infarcts (P = 0.03). Conclusion: Intracranial flow velocity abnormalities are frequent among Indian stroke population. Further studies are needed to characterize these abnormalities fully.

Keywords

• Blunted flow velocities
• Oxfordshire Community Stroke Project classification
• transcranial Doppler