Vascular Access Type and Changes in Infammatory Markers in Incident Dialysis Patients: A Pilot Study

Abstract

To determine the association between the initial hemodialysis (HD) vascular access type and short-term changes in inflammation markers. This is a prospective, observational study in incident chronic kidney disease (CKD) (stages 4 and 5) patients receiving their first HD vascular access. Serum samples were obtained pre-access placement, and 1 week, and 1 month post-access insertion. Samples were tested for high sensitivity C-reactive protein (hsCRP) and interleukin-6 (IL-6) using ELISA. Patients with known inflammatory states (infection, malignancy, connective tissue disorders, organ transplantation and those on immune modulating agents) were excluded. The hsCRP and IL-6 values were transformed into logarithmic scale. Chi-square analysis, independent and paired t-tests were performed where appropriate, and a two-way ANOVA with time as a repeated measure was also performed. Significance was determined at p=0.05. One-month follow-up data was obtained in 48 patients (arteriovenous fistula (AVF), n=10; tunneled catheter (TC), n=28; arteriovenous graft (AVG), n=10). A significant increase in both hsCRP (p <0.05) and IL-6 (p=0.02) occurring 1 week after TC insertion was observed. Elevation of the IL-6 levels appeared to be sustained 1 month after TC insertion, although this finding was not statistically significant (p=0.68), whereas the hsCRP levels returned to baseline within 1 month. After AVG insertion only the hsCRP levels rose significantly (p=0.01) after 1 week and returned to baseline within 1 month. In the AVF group, inflammatory markers did not change for any time period. In CKD patients, TC and AVG insertion result in a transient state of inflammation 1 week post-operatively, which is not observed after AVF surgery. Whether this is a persistent phenomenon after TC insertion requires a larger, longitudinal study.