Study on sex difference of cerebral autoregulation by transcranial Doppler ultrasonography

Abstract

Objective To investigate sex difference of dynamic cerebral autoregulation (dCA) in different body positions. Methods A total of 130 healthy adults (65 males and 65 females) who underwent physical examination in Xuanwu Hospital Capital Medical University from August 2021 to November 2022 were included. Non⁃invasive continuous blood pressure monitor and transcranial Doppler ultrasonography (TCD) were used to monitor beat⁃to⁃beat blood pressure and middle cerebral artery (MCA) cerebral blood flow velocity (CBFV), respectively. Transfer function analysis (TFA) was used to compare and analyze the dCA parameters (absolute gain value and percentage gain, phase, coherence) in the range of very low frequency (0.02-0.07 Hz), low frequency (0.07-0.20 Hz) and high frequency (0.20-0.50 Hz) of different positions and sex. Results The phase in very low frequency and low frequency were significantly lower in the standing position than in the supine position [(57.37 ± 12.45)° vs. (66.72 ± 16.64)°, t = ⁃ 6.428, P = 0.000; (36.82 ± 11.59)° vs. (43.02 ± 11.51)°, t = ⁃ 6.052, P = 0.000], while the coherence in very low frequency and low frequency were significantly higher in the standing position than in the supine position (0.73 ± 0.06 vs. 0.66 ± 0.06, t = ⁃ 8.947, P = 0.000; 0.76 ± 0.06 vs. 0.73 ± 0.07, t = ⁃ 2.693, P = 0.007). In both supine and standing positions, absolute gain value of male in the low frequency [(0.91 ± 0.23) cm/(s·mm Hg) vs. (1.04±0.23)cm/(s·mm Hg), t =3.075, P =0.003; (0.84±0.19)cm/(s·mm Hg) vs. (0.95±0.21)cm/(s·mm Hg), t = 3.102, P = 0.002] and high frequency [(0.94 ± 0.25) cm/(s·mm Hg) vs. (1.11 ± 0.27) cm/(s·mm Hg), t = 3.740, P = 0.000; (0.91 ± 0.21) cm/(s·mm Hg) vs. (1.05 ± 0.23) cm/(s·mm Hg), t = 3.747, P = 0.000] was lower than those of female, while the phase in the low frequency was higher than that of female [(45.25 ± 10.21)° vs. (40.81 ± 12.37)°, t = ⁃ 2.239, P = 0.027; (38.90 ± 12.25)° vs. (34.74 ± 10.57)°, t = ⁃ 2.072, P = 0.040]. Conclusions Postural changes can also affect the cerebral autoregulation, and dCA can be improved in the supine position; there is no significant difference in dCA between male and female in the very low frequency, but there is a certain difference between the sex in the low frequency and high frequency.

Keywords

• ultrasonography, doppler, transcranial
• middle cerebral artery
• blood pressure
• hemodynamics
• posture
• gender identity