Activated Protein C-Resistance Determination and Vascular Access Thrombosis in Populations with High Prevalence of Factor V Leiden.

BACKGROUND/AIMS: Factor V Leiden heterozygosity occurs in 3-8% of the general European and US populations. Activated protein C resistance (APC-R)--a non-molecular laboratory test--can efficiently demonstrate the presence of this mutation and can be performed on most coagulation analyzers. On the other hand, fistula or graft thrombosis is a common and costly complication in hemodialysis patients. Our aim was to establish the value of APC-R determination in hemodialysis patients by assessing the risk of access thrombosis in patients with increased APC-R.

METHODS: A total of 133 patients (81 men, mean age 64.5 ± 14.9 years and 52 women, mean age 63.6 ± 15 years) were selected. Participants were divided into 2 groups: those with access thrombosis (54 patients, 40.6%) and those with no access thrombosis (79 patients, 59.4%), and they were tested for the most common congenital or acquired thrombophilia risk factors.

RESULTS: Overall, 12 patients (9%) had an increased APC-R and 10 of them had at least 1 episode of access thrombosis (83.3%). Univariate analysis to estimate crude odds ratio (OR) showed an OR of 8.8 (95% CI 1.8-41.8) times higher risk for access thrombosis in these patients. No significant differences were found after adjusting for age, hypertension, diabetes mellitus, coronary artery disease, cerebrovascular disease, peripheral arterial disease and malignancy. Sex was also a factor influencing thrombosis, presenting a higher OR for women (OR 2.2, 95% CI 1.1-4.4).

CONCLUSION: This study revealed a significant association between access thrombosis and increased APC-R in hemodialysis patients. This indicates that the determination of APC-R should be considered--especially, in populations with a high prevalence of Factor V Leiden--as proper anticoagulant therapy in these patients may reduce the risk of access thrombosis.