Aortic Pulse Wave Velocity and Extracellular Water Expansion in Hemodialysis Patients.

Background: Pulse wave velocity (PWV), a measurement of arterial stiffness, is a risk factor for cardiovascular mortality in hemodialysis patients. Debate continues as to whether PWV is increased by volume overload. As such, we reviewed the association between volume overload and PWV.

Methods: We measured aortic PWV (aPWV) in hemodialysis patients attending routine dialysis sessions with contemporaneous measurements of extracellular water/total body water (ECW/TBW) ratios using multifrequency bioimpedance.

Results: A total of 102 patients, 63.7% male, mean age 63.5 ± 15.9 years, 44.1% diabetic, median dialysis duration 22.2 (4.9-52.8) months, weight 73.7 ± 15.8 kg, and central systolic blood pressure 157 ± 35 mmHg had a mean aPWV of 10.1 ± 2.5 m/s. Patients dialyzed with a low dialysate calcium (median 1.0 [1.0-1.25] mmol/L). Patients with aPWV of ≥ 10 m/s were older (72.9 ± 10.3 vs. 52.6 ± 14.4 years, p < 0.01) with a higher ECW/TBW ratio (40.6 ± 1.3 vs. 39.6 ± 1.7, p < 0.001), with no differences in active vitamin D₃ or calcium-containing medications. Aortic PWV was associated with age (r = 0.9, p < 0.001) and ECW/TBW (r = 0.33, p = < 0.001), and after adjusting aPWV for age, ECW/TBW remained higher (40.5 ± 1.5 vs. 39.5 ± 1.5, p < 0.001). On multivariable testing, ECW/TBW remained independently associated with a raised aPWV (odds ratio [OR] 1.59 (95% confidence intervals [CI] 1.06-2.41), p = 0.026), and after age adjustment (OR 1.74 (95% CI 1.19-2.53, p = 0.004)).

Conclusions: This study highlights the association between volume overload, as determined by bioimpedance in hemodialysis patients, and arterial stiffness measured by aPWV. These results would reinforce the importance of improving volume control in hemodialysis patients to reduce cardiovascular risk.