Aortic Pulse Wave Velocity in Peritoneal Dialysis Patients Is Not Simply Associated with Extracellular Water Expansion

Background: Cardiac death is increased in peritoneal dialysis (PD) patients. Pulse wave velocity (PWV) is a measurement of arterial stiffness, and previous reports linked PWV to increased extracellular water (ECW). As cyclers and icodextrin are increasingly used, we wished to determine whether this association between PWV and ECW remains. Methods: We measured aortic PWV (aPWV) and bioimpedance (InBody, Seoul, South Korea) in consecutive PD patients attending for peritoneal membrane testing. Results: 189 patients were included, 62.4% male, mean age 63.1 ± 15.2 years, 45.3% diabetic, median dialysis duration 12.3 (6.5–25.1) months, 71.4% using cyclers, weight 73.0 ± 16.1 kg, systolic blood pressure 142 ± 21 mm Hg, aPWV 10.4 ± 5.1 m/s. aPWV was associated with pulse pressure (r = 0.26, p = 0.001), Davies comorbidity score (r = 0.18, p = 0.013), and N-terminal pro-brain-type natriuretic peptide (NTproBNP; r = 0.18, p = 0.011). Patients with aPWV ≥10 m/s were older (65.9 ± 13.6 vs. 60.1 ± 16.3 years, p < 0.01) with a higher ECW-to-total body water ratio (0.400 ± 0.012 vs. 0.396 ± 0.013, p < 0.05), but ECW/height was not different (8.52 ± 2.32 vs. 8.75 ± 1.78 L/m), as was NTproBNP (2,472 [788–5,422] vs. 1,234 [410–6,230] ng/L). On multivariable testing, aPWV was positively associated with β-blocker prescription (standardised β coefficient [Stβ] 0.3, 95% confidence limits [95% CL] 0.7–2.6, p = 0.001) and negatively with icodextrin prescription (Stβ 0.19, 95% CL –0.2 to –2.1, p = 0.04). Conclusions: Compared to previous studies, we did not find an independent association between aPWV and ECW and estimates of ECW excess, using the InBody bioimpedance device, suggesting that vascular stiffness in PD patients is more complex than simple ECW volume expansion in PD patients.