Determinants of increased central excess pressure in dialysis: role of dialysis modality and arteriovenous fistula

Background: Arterial reservoir-wave analysis (RWA) - a new model of arterial hemodynamics - separates arterial wave into reservoir pressure (RP) and excess pressure (XSP). The XSP integral (XSPI) has been associated with increased risk of clinical outcomes. The objectives of the present study were to examine the determinants of XSPI in a mixed cohort of hemodialysis (HD) and peritoneal dialysis (PD) patients, to examine whether dialysis modality, and presence of an arteriovenous fistula (AVF) are associated with increased XSPI.

Method: In a cross-sectional study, 290 subjects (232 HD, and 130 with AVF) underwent carotid artery tonometry (calibrated with brachial diastolic and mean blood pressure). The XSPI was calculated through RWA using pressure-only algorithms. Logistic regression was used for determinants of XSPI above median. Through forward conditional linear regression, we examined whether treatment by HD or presence of AVF is associated with higher XSPI.

Results: Patients with XSPI> median were older, had a higher prevalence of diabetes and cardiovascular disease, had a higher body mass index and were more likely to be on HD. After adjustment for confounders, HD was associated with a higher risk of higher XSPI (OR=2.39, 95%CI:1.16-4.98). In a forward conditional linear regression analysis, HD was associated with higher XSPI (standardized coefficient: 0.126, P=0.012), but upon incorporation of AVF into the model, AVF was associated with higher XSPI (standardized coefficient: 0.130, P=0.008) and HD was excluded as a predictor.

Conclusion: This study suggests that higher XSPI in HD patients is related to the presence of AVF.