Enhanced external counterpulsation does not compromise cerebral autoregulation.
OBJECTIVE
Enhanced external counterpulsation (EECP) rhythmically augments blood pressure (BP) by diastolic lower-body compression. Recently, we showed decreased mean cerebral blood flow velocity (CBFVmean) in young healthy persons during EECP, but unchanged CBFVmean in atherosclerotic patients. In this study, we assessed EECP effects on dynamic cerebral autoregulation (CA).


METHODS
In 23 healthy persons and 15 atherosclerotic patients we monitored heart rate (HR), mean BP (BPmean) and CBFVmean before and during 5 min EECP. We analyzed spectral powers of HR, BPmean and CBFVmean in the low (LF: 0.04-0.15 Hz) and high (HF: 0.15-0.5 Hz) frequency ranges to determine CA from the LF-transfer function gain and phase shift between BPmean and CBFVmean oscillations.


RESULTS
EECP increased HR and BPmean, while transfer function gain and phase shift remained stable.


CONCLUSIONS
Stable gain and phase values suggest that EECP does not compromise CA and, therefore, does not seem to bear cerebrovascular risks.
Marthol
H
H
Department of Neurology, University of Erlangen-Nuremberg, Erlangen, Germany.
Werner
D
D
Brown
C M
CM
Hecht
M
M
Daniel
W G
WG
Hilz
M J
MJ
D000328:Adult; D000367:Age Factors; D000368:Aged; D001161:Arteriosclerosis / Q000503:physiopathology*; D001794:Blood Pressure / Q000502:physiology*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D015908:Counterpulsation; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006706:Homeostasis / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged