Microcirculatory hemodynamics and endothelial dysfunction in systemic lupus erythematosus.
OBJECTIVE
Impaired flow-mediated dilation (FMD) occurs in disease states associated with atherosclerosis, including SLE. The primary hemodynamic determinant of FMD is wall shear stress, which is critically dependent on the forearm microcirculation. We explored the relationship between FMD, diastolic shear stress (DSS), and the forearm microcirculation in 32 patients with SLE and 19 controls.


RESULTS
DSS was calculated using (mean diastolic velocity x 8 x blood viscosity)/baseline brachial artery diameter. Doppler velocity envelopes from the first 15 seconds of reactive hyperemia were analyzed for resistive index (RI), and interrogated in the frequency domain to assess forearm microvascular hemodynamics. FMD was significantly impaired in SLE patients (median, 2.4%; range, -2.1% to 10.7% versus median 5.8%; range, 1.9% to 14%; P<0.001). DSS (dyne/cm2) was significantly reduced in SLE patients (median, 18.5; range, 3.9 to 34.0 versus median 21.8; range, 14.1 to 58.7; P=0.037). A strong correlation between FMD and DSS, r(s)=0.65, P=0.01 was found. Postischemic RI was not significantly different between the 2 groups; however, there were significant differences in the power-frequency spectrums of the Doppler velocity envelopes (P<0.05).


CONCLUSIONS
These data suggest that in SLE, altered structure and function of the forearm microcirculation contributes to impaired FMD through a reduction in shear stress stimulus.
Wright
Stephen A
SA
Department of Therapeutics and Pharmacology, Whitla Medical Building, Queens University Belfast, BT9 7BL, Northern Ireland. s.wright@qub.ac.uk
O'Prey
Fiona M
FM
Rea
Derrick J
DJ
Plumb
Rick D
RD
Gamble
Andrew J
AJ
Leahey
William J
WJ
Devine
Adrian B
AB
McGivern
R Canice
RC
Johnston
Dennis G
DG
Finch
Michael B
MB
Bell
Aubrey L
AL
McVeigh
Gary E
GE
D000328:Adult; D001783:Blood Flow Velocity; D001916:Brachial Artery / Q000000981:diagnostic imaging / Q000503:physiopathology; D015331:Cohort Studies; D004730:Endothelium, Vascular / Q000503:physiopathology*; D005260:Female; D005542:Forearm / Q000098:blood supply*; D006439:Hemodynamics; D006801:Humans; D008180:Lupus Erythematosus, Systemic / Q000000981:diagnostic imaging / Q000503:physiopathology*; D008297:Male; D008833:Microcirculation; D008875:Middle Aged; D012039:Regional Blood Flow; D013314:Stress, Mechanical; D014463:Ultrasonography; D014655:Vascular Resistance; D014664:Vasodilation