Comparison of Autoregulation Index during Sit‐To‐Stand in Young Healthy Individuals across Races

Abstract

Cerebral autoregulation is an important mechanism to protect the brain by maintaining the brain perfusion over varying blood pressures. The cerebral blood flow velocity response to Sit‐To‐ Stand maneuver has been widely used to assess dynamic cerebral autoregulation. Previous work has demonstrated sex differences in autoregulation; however, little is known about the impact of race. Potential racial differences in cerebral autoregulation may contribute to different incidences of cerebrovascular events between different races. Therefore, the purpose of this study was to compare the Autoregulatory index between four different racial groups. We enrolled 55 young healthy subjects (aged 18~35 years) with four racial groups, i.e. White/Caucasian (Age 27±5; n=11; 5 Males), Black/African American (Age 28±6; n=8; 4 Males), Latino (Age 28±6; n=6; 2 Males), and Asian (Age 27±3; n=30; 15 Males). The transcranial Doppler was used to continuously record the cerebral blood flow velocity at middle cerebral artery during 3 repeated sit‐to‐stand maneuvers, with simultaneous measurements of blood pressure, heart rate, and end‐tidal CO2 (ETCO2). There was no difference in demographic variables across groups except for BMI (24±4, 26±4, 27±5, and 23±3; kg/m2, P=0.043). Similarly, there were no differences in baseline cerebral blood flow velocity, blood pressure or heart rate with the exception of ETCO2 (35±3, 40±4, 35±3, and 38±3 mmHg, P=0.003). We found no differences between groups in the physiological response during sit‐to‐stand. Similarly, autoregulatory index was similar across all racial groups (3.6±2.4, 3.9±1.2, 3.3±2.6, and 3.6±1.5, P=0.948). These data suggest that cerebral autoregulation is similar in young healthy individuals across different races. However, these findings must be interpreted with caution due to the small number of participants in the various racial groups. Future studies are warranted to include larger sample size, older subjects and also to consider sex differences within each race. Support or Funding Information Supported by the Funding from Rutgers University and U.S. Department of Defense.