Vasomotor reactivity as a predictor for syncope in patients with orthostatism

• Published in: Acta neurologica Scandinavica Vol. 126; no. 1; pp. 32 - 36
• Main Authors: Gur, A. Y., Auriel, E., Korczyn, A. D., Gadoth, A., Shopin, L., Giladi, N., Bornstein, N. M., Gurevich, T.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.07.2012; Blackwell
• Subjects: acetazolamide; Aged; Aged, 80 and over; Biological and medical sciences; cerebral autoregulation; Cerebrovascular Circulation - physiology; cerebrovascular reactivity; Doppler ultrasonography; Female; Homeostasis - physiology; Human viral diseases; Humans; Hypotension, Orthostatic - complications; Hypotension, Orthostatic - diagnostic imaging; Hypotension, Orthostatic - physiopathology; Infectious diseases; Male; Medical sciences; Middle Aged; Middle Cerebral Artery - diagnostic imaging; Middle Cerebral Artery - physiopathology; Neurology; orthostatic hypotension; Predictive Value of Tests; syncope; Syncope - complications; Syncope - diagnostic imaging; Syncope - physiopathology; transcranial; Ultrasonography; Vasomotor System - diagnostic imaging; Vasomotor System - physiopathology; Viral diseases; Viral diseases of the nervous system; Sonography; Doppler ultrasound study; Human; Doppler ultrasonography; orthostatic hypotension; Nervous system diseases; transcranial; Consciousness impairment; Central nervous system; Cardiovascular disease; Encephalon; Postural hypotension; Syncope; Arterial hypotension; Diseases of the autonomic nervous system; acetazolamide; cerebral autoregulation; Self regulation; cerebrovascular reactivity; Neurological disorder
• ISSN: 0001-6314; 1600-0404
• DOI: 10.1111/j.1600-0404.2011.01591.x

Gur AY, Auriel E, Korczyn AD, Gadoth A, Shopin L, Giladi N, Bornstein NM, Gurevich T. Vasomotor reactivity as a predictor for syncope in patients with orthostatism.
Acta Neurol Scand: 2012: 126: 32–36.
© 2011 John Wiley & Sons A/S. Objectives –  Syncope in patients with orthostatic hypotension (OH) may be the result of impaired cerebral autoregulation. Cerebral autoregulation status can be determined by assessing cerebral vasomotor reactivity (VMR). We assessed and compared VMR in patients with OH with and without syncope. Material and methods –  Twenty‐nine patients with OH underwent transcranial Doppler (TCD) and the Diamox test (1 g acetazolamide IV) for assessing VMR during elaboration of their OH syndrome. The percent difference between cerebral blood flow velocities (BFV) in the middle cerebral (MCA) and vertebral (VA) arteries before and after acetazolamide was defined as VMR%. We considered increases of BFV of ≥40% as being indicative of good VMR and classified our study patients as having good or impaired VMRs accordingly. Results –  Mean VMR% values of the MCA and VA in patients with OH with syncope (n = 12) were significantly lower as compared with patients with OH without syncope (n = 17): 25.2 ± 20.5% and 42.5 ± 18.6%; 20.9 ± 15.5% and 40.8 ± 28.5%, respectively (P < 0.05). Conclusions –  Among patients with OH, we found an association between the presence of syncope and impaired VMR. Assessment of VMR among patients with OH may predict those who are at higher risk to faint and fall and to support more aggressive intervention.