Determinants of Increased Central Excess Pressure in Dialysis: Role of Dialysis Modality and Arteriovenous Fistula

Abstract

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 the 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 the presence of AVF is associated with higher XSPI. RESULTS Patients with XSPI above 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 (odds ratio = 2.39, 95% confidence interval: 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 on 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.

Arteriovenous Fistula Creation and Estimated Glomerular Filtration Rate Decline in Advanced CKD: A Matched Cohort Study

“…Additionally, the resultant increase in venous return has been proposed to promote blood flow in underperfused lung areas, which may increase blood oxygen delivery to the kidneys, decreasing the renal chemoreflex responsible for vasoconstriction through central sympathetic activation. 18 AVF creation has also been linked with an increased myocardial oxygen demand 29 and left ventricular hypertrophy 30 , and an increase in excess pressure integral, in turn associated with adverse cardiovascular outcomes 31 . However, these changes are only described in ESKD patients, where a longstanding abnormal development of the AVF may contribute to adverse hemodynamic changes.…”

Increased Excess Pressure After Creation of an Arteriovenous Fistula in End-Stage Renal Disease

“… 13 , 14 In addition, our previous findings show that XSPI was statistically higher in ESRD patients with an AVF. 15 Indeed, if XSP is analogous to flow, it is conceivable the creation of AVF could increase XSP. In the present study, our aim was to assess the impact of creation of an AVF on reservoir-wave parameters in ESRD patients, in a before and after study design.…”