Antiphospholipid Antibody Persistent Positivity Is Associated with Worsened Endothelial Dysfunction in Hemodialysis Patients: A Cross-Sectional Study

<b>Introduction</b>: Endothelial dysfunction is a common feature of end-stage kidney disease, requiring hemodialysis (HD) and antiphospholipid antibody (aPL) persistent positivity. Endothelial dysfunction can be assessed with noninvasive tests such as flow-mediated dilation (FMD). In the HD population, it is not known whether aPL persistent positivity is associated with a more severe endothelial dysfunction. <b>Methods</b>: We performed a cross-sectional study in our HD patients. The FMD of the brachial artery was measured in 17 aPL-positive patients who fulfilled the inclusion criteria and were matched to 17 controls according to age, gender, diabetes mellitus, smoking status and markers of dialysis adequacy (Kt/V). <b>Results</b>: FMD was significantly lower in the aPL group with a mean of 6.9% and 11.8% in the aPL-positive and the control groups, respectively (mean difference (IC 95%): -4.9 (-8.3; -1.6), <i>p</i> = 0.006). aPL was associated with a higher c-reactive protein level, and longer HD vintage. There was no statistical difference between groups in terms of pre-dialysis urea and urinary output, dialysis adequacy (Kt/V), and history of cardiovascular disease or treatments. <b>Conclusions</b>: aPL persistent positivity in HD patients was associated with worse endothelial dysfunction, reflected by FMD measurements. These findings have to be confirmed in larger studies.