Arteriovenous fistula thrombosis in hemodialysis patients with COVID-19: epiphenomenon or marker of severe clinical disease?

Background: Pandemic condition due to Coronavirus disease (COVID-19) caused a fastest augmentation of hospitalization, impairing the healthcare organization. As a consequence, diagnostic and therapeutic delays have been showed. COVID-19-associated coagulopathy is an endothelial disease related to SARSCoV-2 infection. Our study evaluated the thrombosis of arteriovenous fistula (AVF) as risk marker of mortality. Methods: the analysis included 24 dialysis-dependent patients admitted in a period between March 2020 and June 2021. Patients were divided based on AVF thrombosis: the A group without AVF thrombosis (13 patients), and the B group with AVF thrombosis events (11 patients). Pearson or Spearman' correlation tests were performed to detect possible confounding variable to include in multivariate models. Kaplan Meier and Cox regression analysis were performed to compute mortality analysis. Results: Delta D-dimer (Rho: 0.613, p=0.007), over-infections (Rho 0.456; p= 0,026), C-reactive Protein (CRP) (Rho=0.417, p=0.043), death (Rho=0.492, p=0.027), positive pulmonary imaging (Rho 0.388, p=0.074), and high OLT (0.408, p=0.047) were related to AVF thrombosis, using Pearson or Spearman correlation tests. Kaplan Meier test showed a death average of 19 days in group B compared to a global average of 38 days (p=0.029), and Cox analysis showed an HR of 5.01, 95% CI 1.01-24.99, p=0.049. Furthermore, AVF thrombosis explained about the 68% of the mortality, evaluated through the Harrel's C test. Conclusion: We can speculate that AVF thrombosis in hemodialysis patients with COVID-19 could be an early marker of both pro-coagulative process and severe clinical disease and it could be used to stratify patients and identify the ones that can be considered "frail".