Renal Venous Stasis Index Reflects Renal Congestion and Predicts Adverse Outcomes in Patients With Heart Failure

Figures

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  Figure 1. All renal Doppler ultrasonography studies were performed in the right kidney. Color Doppler images were used to record pulsed Doppler waveforms of the interlobar arteries and veins simultaneously. The upward Doppler signal indicated the intrarenal arterial flow, and the downward Doppler signal indicated the venous flow. We measured venous flow time and calculated RVSI as follows: (cardiac cycle time-venous flow time)/cardiac cycle time. RVSI of 0 was defined as the control. RVSI above 0 were divided based on the median value of RVSI (0.21): the low RVSI (0 < RVSI ≤ 0.21) and the high RVSI (RVSI > 0.21). RVSI increased with increasing severity of renal congestion. This figure shows representative IRVF patterns with RVSI in a patient with HF. IRVF patterns were broadly categorized into continuous (RVSI = 0, non-congestive) and discontinuous (RVSI > 0, nadir velocity = 0) flow patterns. We further classified the discontinuous IRVF patterns into two stages: biphasic (with venous peaks during systole and diastole), and monophasic (with venous peak during diastole). (a) RVSI = 0 (control) with continuous pattern; (b) low RVSI with biphasic pattern; (c) high RVSI with biphasic pattern;…

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  Figure 2. The severity of renal congestion can be assessed by measuring RVSI using renal Doppler ultrasonography. (A,C–E) show the relationship between RVSI and mRAP (A) IRVF patterns (C) severity of TR (D) and TAPSE/sPAP ratio (E). RVSI showed a significant stepwise increase along the IRVF patterns (C; P < 0.001) and severity of tricuspid regurgitation (D; P < 0.001). TAPSE/sPAP ratio showed a significant stepwise decrease along the RVSI groups (E; P < 0.001). In addition, both RVSI and IRVF patterns showed similar associations with elevated mRAP (A; P < 0.001 and B; P = 0.001). RVSI, renal venous stasis index; mRAP, mean right atrial pressure; IRVF, intrarenal venous flow; TR, tricuspid regurgitation; TAPSE/sPAP, tricuspid annular plane systolic excursion/systolic pulmonary artery pressure; IQR, interquartile range.

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  Figure 3. Kaplan–Meier analysis for cardiac event rates stratified by RVSI. The cumulative cardiac event rate significantly increased with increasing RVSI (log-rank, P = 0.001). RVSI, renal venous stasis index.

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  Figure 4. Kaplan–Meier analysis for cardiac event rate stratified by IRVF patterns. The cumulative cardiac event rate significantly increased with worsening IRVF patterns (log-rank, P = 0.002). Although it showed basically similar to those of RVSI classification, there were overlap and inversion between the groups with biphasic and monophasic IRVF patterns. IRVF, intrarenal venous flow.