Impaired brachial artery endothelial flow-mediated dilation and orthostatic stress in hemodialysis patients.
OBJECTIVE
Chronic kidney disease (CKD) is associated with an impaired endothelial function, which may contribute to cardiovascular events. Whether impairment in endothelial function is involved in the circulatory response to orthostatic stress is unknown. We assessed endothelial function via brachial artery flow-mediated dilation (BAFMD), an index of endothelial-dependent vasodilation.


METHODS
We measured changes in brachial artery diameter (BAD) and blood flow by Doppler ultrasound in 35 CKD patients on hemodialysis, 37 young healthy controls (HC) and 50 non-uremic matched controls (MC), in the supine position and after 60 degrees head-up tilting (HUT).


RESULTS
In the supine position, endothelial flow-mediated BAD was significantly increased in HC (p<0.001) and MC (p<0.01) while no significant changes were detected in CKD. Mean percent blood flow changes were HC+323.5%, MC+195.1% and CKD+158.8% (HC vs. CKD p<0.001; HC vs. MC p<0.001; MC vs. CKD p=0.04). Similarly, during HUT mean BAD and blood flow increases were significantly impaired in CKD patients.


CONCLUSIONS
In CKD patients, an impaired response in the physiologic vascular reactivity, suggesting endothelial dysfunction, was found in the supine position and after orthostasis by BAFMD. Our results are in favor of a possible adjunctive role of uremia in the abnormal brachial artery response.
Gallieni
M
M
Nephrology and Dialysis Unit, San Paolo Hospital, University of Milan, Milan - Italy. maurizio.gallieni@fastwebnet.it
Butti
A
A
Guazzi
M
M
Galassi
A
A
Cozzolino
M
M
Brancaccio
D
D
D000328:Adult; D001783:Blood Flow Velocity / Q000502:physiology; D001916:Brachial Artery / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology*; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D007676:Kidney Failure, Chronic / Q000503:physiopathology*; D008297:Male; D006435:Renal Dialysis / Q000009:adverse effects*; D018667:Tilt-Table Test; D014463:Ultrasonography; D014511:Uremia / Q000503:physiopathology*; D014664:Vasodilation / Q000502:physiology*