Kidney Week

Abstract: TH-PO464

Renal Resistive Index in Cortical but Not in Segmental Arteries Reflects Renal Perfusion in Hypertensive CKD Patients

Session Information

• CKD: Epidemiology, Outcomes - Cardiovascular - I
  November 02, 2017 | Location: Hall H, Morial Convention Center
  Abstract Time: 10:00 AM - 10:00 AM

Category: Chronic Kidney Disease (Non-Dialysis)

• 303 CKD: Epidemiology, Outcomes - Cardiovascular

Authors

• Lubas, Arkadiusz, Military Institute of Medicine, Warsaw, Poland

Arkadiusz Lubas,

• Niemczyk, Stanislaw, Military Institute of Medicine, Warsaw, Poland

Stanislaw Niemczyk,

Background

Renal Resistive Index in segmental arteries (RI-S) is a well known marker of cardiovascular and renal organ damage. In many studies it is used as a marker of Renal Perfusion (RP). However this relation was not proved. Renal Resistive Index in cortical arteries (RI-C) is erroneously used as RI-S, because the difference between these indexes is unclear.
The aim of the study was to investigate relations between segmental and cortical renal Resistive Indexes and Renal Perfusion.

Methods

Fifty patients (3F; 47M; age 56.6 ±13.3) with stable CKD (CKD-EPI 57.4 ±28.4 ml/min/1.73m²) and a history of hypertension were enrolled in the study. Ultrasonic color and duplex Doppler examinations of intrarenal arteries in the right kidneys were performed. RI-S was calculated as a mean of 3 measurements. RI-C and RP (arterio-venous mean perfusion [mL/s]) were calculated with the use of Dynamic Tissue Perfusion Method (PixelFlux software). Echocardiographic Cardiac Index (CI), IMT, 24-h Pulse Pressure (PP) and renal function expressed as Creatinine and Cystatin based CKD-EPI formula were estimated.

Results

Renal Resistive Indexes were significantly correlated (r=0.63; R²=0.40; p<0.001), but RI-S was lower than RI-C (0.684 ±0.075 vs 0.728 ±0.131; p=0.004). In the univariable analysis RI-S and RI-C both were significantly correlated with age, IMT, PP, CI, CKD-EPI, and RP. The multivariable regression analysis adjusted to age and BMI showed that CKD-EPI (p<0.001), CI (p=0.005) and PP (p=0.014) independently influenced RI-S (R²=0.55, p<0.001). The same analysis for RI-C revealed an independent relation (R²=0.41, p<0.001) with PR (p<0.001) and CI (p=0.024). When RI-S was added to the regression equation PR (p<0.001) and RI-S (p<0.001) independently modified RI-C (R²=0.51, p<0.001).

Conclusion

Renal Resistive Index in segmental arteries is independently modified by cardiovascular and renal organ damage parameters with the exclusion of the Renal Perfusion. Although RI-S and RI-C correlate with each other, their values differ significantly. Renal cortical Resistive Index reflects both Renal Perfusion and segmental Resistive Index. Segmental and cortical renal Resistive Indexes cannot be used interchangeably.

Funding

• Government Support - Non-U.S.