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Abstract: PO2147

Extracellular Volume, Peripheral Resistance, and Cardiac Index May Be Altered in Early CKD

Session Information

Category: Hypertension and CVD

  • 1403 Hypertension and CVD: Mechanisms

Authors

  • Gregg, L Parker, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, United States
  • Van Buren, Peter N., University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, United States
  • Banerjee, Subhash, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, United States
  • Hedayati, Susan, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, United States
Background

It is unknown if extracellular volume (ECV), cardiac index (CI), and peripheral resistance are altered in early stages of chronic kidney disease (CKD) before significant decline in glomerular filtration rate (GFR) or if these can be identified by routine laboratory measurements.

Methods

A total of 21 participants, including 13 with CKD stages 1-3 and 8 non-CKD controls, were prospectively recruited from outpatient clinics. CKD stage 3 was defined as an estimated GFR (eGFR) of 30-59 mL/min/1.73 m2, and stages 1-2 as a urine albumin-to-creatinine ratio >30 mg/g and eGFR ≥60. ECV was measured using bioimpedance spectroscopy and normalized to total body weight. CI and total peripheral resistance index (TPRI) were measured using non-invasive cardiac output monitoring. Measurements were compared using Fisher exact tests, Student’s t tests, and Pearson correlations.

Results

Participants with CKD had a mean (SD) age of 65.4 (12.9) years vs. 59.8 (13.5) years for controls, P=0.36. Mean eGFR in the CKD group was 47.0 (17.9) mL/min/1.73 m2. In the CKD group there were 8 (61.5%) with diabetes, vs. 3 (37.5%) controls, P=0.39. Mean systolic blood pressure was 159.2 (22.3) in the CKD group vs. 143.1 (26.2) in the control group, P=0.17. Edema was present in 9 (69.2%) of the CKD group vs. 2 (25.0%) controls, P=0.08. Mean (SD) ECV/weight was marginally higher in the CKD group than in controls, 27.4% (3.7) vs. 24.7% (2.6), P=0.06. The CKD group had higher b-type natriuretic peptide (BNP), 182.8 (236.0) vs. 33.4 (35.4) pg/mL, P=0.04, lower CI, 2.4 (0.4) vs. 3.0 (0.5), P=0.04, and higher TPRI, 3800.2 (645.7) vs. 2980.8 (263.5) dyn.s.cm-5, P=0.001. Log-transformed BNP correlated with CI, r=-0.77, P=0.0002, and TPRI, r=0.50, P=0.04 (Table). ECV/weight did not correlate strongly with CI, r=-0.27, P=0.29, and TPRI, r=0.25, P=0.32.

Conclusion

In this hypothesis-generating study, patients with CKD had higher TPRI and lower CI than non-CKD controls. CI and TPRI correlated with BNP but not with ECV/weight. BNP, an easily measured and universally available test, may be used as a correlate for CI and TPRI in patients with early stage CKD. These findings need to be confirmed in larger cohorts.

 CKD (N=13)Non=CKD (N=8)P valueEntire Cohort (N=20)CKD (N=13)Non-CKD (N=7)
Log BNP, Pearson rP valueLog BNP, Pearson rP valueLog BNP, Pearson rP value
CI, L/min/m22.4 (0.4)3.0 (0.5)0.04-0.770.0002-0.640.02-0.900.02
TPRI, dyn.s.cm-53800.2 (645.7)2980 (263.5)0.0010.500.040.290.310.660.16

Funding

  • Veterans Affairs Support