Oscillatory Cerebral Blood Flow Is Associated With Impaired Neurocognition and Functional Hyperemia in Postural Tachycardia Syndrome During Graded Tilt

Authors

Julian M. Stewart, From the Departments of Pediatrics (J.M.S., A.T.D.P., A.P., Z.R.M., C.T., M.S.M.) and Physiology (J.M.S., M.S.M.), New York Medical College, Valhalla. julian_stewart@nymc.edu.
Andrew T. Del Pozzi, From the Departments of Pediatrics (J.M.S., A.T.D.P., A.P., Z.R.M., C.T., M.S.M.) and Physiology (J.M.S., M.S.M.), New York Medical College, Valhalla.
Akash Pandey, From the Departments of Pediatrics (J.M.S., A.T.D.P., A.P., Z.R.M., C.T., M.S.M.) and Physiology (J.M.S., M.S.M.), New York Medical College, Valhalla.
Zachary R. Messer, From the Departments of Pediatrics (J.M.S., A.T.D.P., A.P., Z.R.M., C.T., M.S.M.) and Physiology (J.M.S., M.S.M.), New York Medical College, Valhalla.
Courtney Terilli, From the Departments of Pediatrics (J.M.S., A.T.D.P., A.P., Z.R.M., C.T., M.S.M.) and Physiology (J.M.S., M.S.M.), New York Medical College, Valhalla.
Marvin S. Medow, From the Departments of Pediatrics (J.M.S., A.T.D.P., A.P., Z.R.M., C.T., M.S.M.) and Physiology (J.M.S., M.S.M.), New York Medical College, Valhalla.

Author Type(s)

Faculty

DOI

10.1161/HYPERTENSIONAHA.114.04576

Journal Title

Hypertension

First Page

636

Last Page

43

Document Type

Article

Publication Date

3-1-2015

Abstract

We hypothesize that upright cognitive impairment in patients with postural tachycardia syndrome (POTS) is caused by reduced cerebral blood flow (CBF). The CBF velocity (CBF(v)) measured by transcranial Doppler ultrasound decreased excessively during 70° tilt in a minority of patients with intermittent hyperpnea/hypocapnia. Incremental tilt showed no difference in mean CBF(v). But N-back memory tasking indicated progressive compromised memory, reduced functional hyperemia, and reduced neurovascular coupling. Orthostasis caused slow oscillations in CBF(v) linked to oscillations in arterial pressure in patients with POTS. We also hypothesize that oscillatory CBF(v) degrades neurovascular coupling. We performed 2-back testing when subjects were in supine position and during incremental tilts to 15°, 30°, 45°, and 60° in 11 patients with POTS and 9 controls. Oscillatory arterial pressure, oscillatory CBF(v), and neurovascular coupling were similar in supine position. The oscillatory arterial pressure increased by 31%, 45%, 67%, and 93% in patients with POTS during tilt and remained unchanged in the controls. Oscillatory CBF(v) increased by 61%, 82%, 161%, and 264% in patients with POTS during tilt and remained unchanged in the controls. Functional hyperemia decreased from 4.1% to 3.0%, 1.1%, 0.2%, and to 0.04% in patients with POTS, but it was unchanged at 4% in the controls. Percent correct N-back responses decreased from 78% to 33% in patients with POTS, whereas they remained at 89% in the controls. In patients with POTS, oscillatory CBF(v) was linearly correlated with functional hyperemia (r(2)=0.76). Increased oscillatory CBF is associated with reduced neurovascular coupling and diminished cognitive performance in patients with POTS.

Recommended Citation

Stewart, J. M., Del Pozzi, A. T., Pandey, A., Messer, Z. R., Terilli, C., & Medow, M. S. (2015). Oscillatory Cerebral Blood Flow Is Associated With Impaired Neurocognition and Functional Hyperemia in Postural Tachycardia Syndrome During Graded Tilt. Hypertension, 65 (3), 636-43. https://doi.org/10.1161/HYPERTENSIONAHA.114.04576