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. 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 (Ps-Pi), HR corrected augmentation index (AIx@75), and augmentation index decreased significantly [(Ps-Pi): 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 (EDc), round trip travel time (Δtp), and reflected wave systolic duration (Δtr) all increased upon PLR [EDc: 433±15 vs. 444±17, P<0.001; Δtp: 149±18 vs. 156±20, P = 0.003; Δtr: 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.