Key result
Passive leg raising cuts augmentation index ~30% from baseline, reducing wasted left ventricular pressure energy.
Why the study?
Does passive leg raising alter central hemodynamics and arterial wave reflection in healthy adults?
Does passive leg raising alter central hemodynamics and arterial wave reflection in healthy adults?
Absolute Event Rate: 7% vs 10%
p-value: p=0.004
Passive leg raising decreases the amplitude and delays the onset of the reflected aortic pressure wave, thereby reducing wasted left ventricular pressure energy and workload in healthy adults.
May reduce ventricular workload in healthy adults; hypothesis-generating and should not yet change practice.
BACKGROUND: Passive leg raising (PLR) produces hemodynamic and physiological changes related to centralizing blood volume and baroreceptor activation. METHODS/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. CONCLUSION: PLR decreases the amplitude and delays the onset of the reflected aortic pressure wave. This decreases wasted LV pressure energy and workload.
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Kamran et al. (2009) studied Healthy adults (n=50). Passive leg raising vs. Baseline was evaluated on HR corrected augmentation index (AIx@75) (p=0.004). Passive leg raising significantly decreased the heart rate-corrected augmentation index from 10 to 7 (P=0.004) compared to baseline, reducing wasted left ventricular pressure energy.
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