Related Experiment Video
Updated: Jun 9, 2026
Tilt Testing with Combined Lower Body Negative Pressure: a "Gold Standard" for Measuring Orthostatic Tolerance
Published on: March 21, 2013
Different cerebral hemodynamic responses between sexes and various vessels in orthostatic stress tests
Yuh-Jen Wang1, A-Ching Chao, Chih-Ping Chung
1Department of Neurology and Internal Medicine, Taipei City Hospital, Taipei, Taiwan.
Objective:
The argument about why the head-up tilt table test (HUT) does not include the posterior cerebral circulation, which is mainly responsible for syncope, as a monitor target has not been resolved. It is also unclear whether there is a sex difference in cerebral blood flow (CBF) changes. We hypothesized that orthostatic CBF changes more in the posterior circulation than in the anterior circulation and is different between sexes.
Methods:
Thirty healthy volunteers (13 female and 17 male) were recruited for the HUT. The blood pressure (BP), middle cerebral artery flow velocity (MCAFV), and posterior cerebral artery flow velocity (PCAFV) were monitored simultaneously. Static cerebral autoregulation (CA) was calculated.
Results:
The female volunteers had a lower BP, but there was no difference in orthostatic BP changes (female versus male: 1.29% +/- 5.26% versus 4.22% +/- 12.65%; P = .65). The female volunteers had a significantly greater orthostatic drop in the PCAFV than in the MCAFV (23.8% +/- 9.1% versus 18.2% +/- 7.3%; P = .008). The static CA in the middle cerebral artery was better than in the posterior cerebral artery, although not significantly (13.6% +/- 34.8% versus - 2.8% +/- 12.2%; P = .15).
Conclusions:
Our study showed the different cerebral hemodynamic responses between anterior and posterior circulations and between sexes during the HUT. We conclude that HUT studies for syncope should include the posterior cerebral circulation, especially for female patients.
Related Concept Videos
01:26Exercise Stress Test
Exercise stress testing, commonly known as a treadmill test, is a noninvasive procedure used to evaluate cardiovascular function and diagnose heart conditions.
Definition
An exercise stress test measures the heart's response to exertion using a treadmill or stationary bicycle. Chest electrodes record the heart's electrical activity through an ECG, and blood pressure is monitored regularly.
Purposes
01:28Special considerations while measuring blood pressure
Monitoring Both Arms:
Monitoring BP in both arms during the initial assessment is advisable, as the systolic value may differ by five to ten mm Hg between arms. For subsequent BP assessments, use the arm with the higher reading.