Influence of a single hemodialysis on left ventricular energy loss and wall shear stress in patients with uremic cardiomyopathy assessed with vector flow mapping

BACKGROUND: The influence of hemodialysis (HD) on hydromechanics of the left ventricle has not been reported. This study evaluated the left ventricular summation of energy loss (EL-SUM), average energy loss (EL-AVE), and wall shear stress (WSS) before and after HD using vector flow mapping (VFM) in patients with end-stage renal disease (ESRD). METHODS: We prospectively recruited 40 patients receiving long-term HD and excluded those with structural cardiac disease. Echocardiography was performed before and within 24 hours after HD. Conventional echocardiographic parameters, summation, and average energy loss (EL-SUM, EL-AVE, EL-base, EL-mid and EL-apex), and WSS in each segment were compared. RESULTS: A total of 40 patients with uremia were recruited. After HD, left ventricular EL-AVE-total, and EL-SUM-total decreased significantly in the early diastolic [29.43 (18.76 to 46.28) vs. 17.70 (10.76 to 95.60) N/(m(2)·s) and 12 (6 to 17) vs. 5 (3 to 11) e(−2) J; P<0.001, respectively], mid-diastolic [17.07 (10.38 to 24.35) vs. 10.29 (5.86 to 16.30) N/(m(2)·s) and 7 (3 to 10) vs. 4 (2 to 6) e(−2) J; P<0.001, respectively], and early systolic [17.82 (12.79 to 24.77) vs.14.90 (10.23 to 19.05) N/(m(2)·s) P=0.011 and 8 (5 to 11) vs. 5 (4 to 8) e(−2) J, P=0.002, respectively] phases. It was revealed that HD did not change EL-AVE-total and EL-SUM-total in the late diastolic and late systolic phases. The EL-AVE decreased after HD in the left ventricular (LV) basal [50.70 (24.19 to 77.92) vs. 26.00 (11.50 to 47.68) N/(m(2)·s); P<0.001] and mid [15.52 (8.88 to 20.90) vs. 9.47 (6.41 to 14.21) N/(m(2)·s); P=0.001] segments during the early diastolic phase; in the LV basal [18.64 (10.33 to 29.80) vs. 10.25 (6.98 to 19.43) N/(m(2)·s); P<0.001), mid (15.70 (9.93 to 23.08) vs. 9.99 (6.03 to 16.25) N/(m(2)·s); P<0.001), and apical [9.78 (4.06 to 15.77) vs. 4.52 (3.14 to 10.36) N/(m(2)·s); P=0.001) segments during the mid-diastolic phase; in the LV mid [14.34 (8.34 to 23.88) vs. 9.36 (6.48 to 17.05) N/(m(2)·s); P=0.013] and apex [11.25 (6.37 to 21.88) vs. 6.60 (5.33 to 12.17) N/(m(2)·s); P=0.016] segments during the late diastolic phase; and in the apical [10.28 (6.05 to 17.01) vs. 7.59 (3.73 to 13.20) N/(m(2)·s) P=0.025] segment during the early systolic phase. After HD, WSS significantly reduced in the mid-diastolic [0.51 (0.32 to 0.69) vs. 0.38 (0.30 to 0.46) Pa, P=0.001] and early systolic [0.60 (0.45 to 0.81) vs. 0.57 (0.42 to 0.68) Pa, P=0.029] phases. There was no change in WSS during the early diastolic, late diastolic, and late systolic phases. CONCLUSIONS: After HD, EL and WSS of LV decrease during the systolic and diastolic phases. The VFM can reflect the LV hemodynamics in patients undergoing HD under different fluid loads.