The effects of passive leg raising on arterial wave reflection  in healthy adults.
BACKGROUND
Passive leg raising (PLR) produces hemodynamic and physiological changes related to centralizing blood volume and baroreceptor activation.


RESULTS
To evaluate the effects of PLR on central hemodynamics, we prospectively studied 50 healthy participants (80% male, age 37 +/- 12 years). Central aortic blood pressures (CA-BPs) and reflected wave properties were evaluated using applanation tonometry at baseline and upon 1 min of PLR. Heart rate (HR) was unchanged. Brachial artery (BA)-systolic BP, BA-diastolic BP, and BA-pulse pressure (PP) all decreased from baseline to PLR. Changes in BA-PP were significantly greater than changes in CA-PP. Reflected wave augmentation pressure (P(s)-P(i)), HR corrected augmentation index (AIx@75), and augmentation index decreased significantly [(P(s)-P(i)): 5 +/- 6 vs. 4 +/-5, P < 0.001; AIx@75%: 10 +/- 13 vs. 7 +/- 12, P = 0.004; AI%: 14 +/- 12 vs. 12 +/- 12, P = 0.014, respectively]. HR corrected ejection duration (ED(c)), round trip travel time (deltat(p)), and reflected wave systolic duration (deltat(r)) all increased upon PLR [ED(c): 433 +/- 15 vs. 444 +/- 17, P < 0.001; deltat(p): 149 +/- 18 vs. 156 +/- 20, P = 0.003; deltat(r): 174 +/- 33 vs. 179 +/- 32, P = 0.046, respectively]. Indices of left ventricular (LV) workload including wasted LV energy and tension-time index decreased upon PLR.


CONCLUSIONS
PLR decreases the amplitude and delays the onset of the reflected aortic pressure wave. This decreases wasted LV pressure energy and workload.
Kamran
Haroon
H
Division of Cardiovascular Medicine, State University of New York Downstate Medical Center, Brooklyn, New York 11203-2098, USA.
Salciccioli
Louis
L
Gusenburg
Jeffery
J
Kazmi
Haris
H
Ko
Eun Hee
EH
Qureshi
Ghazanfar
G
Lazar
Jason M
JM
D000328:Adult; D001783:Blood Flow Velocity; D001794:Blood Pressure / Q000502:physiology*; D001916:Brachial Artery; D005260:Female; D006439:Hemodynamics; D006801:Humans; D007866:Leg / Q000098:blood supply* / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D011311:Pressoreceptors / Q000502:physiology; D011446:Prospective Studies; D011673:Pulsatile Flow; D016683:Supine Position