The von Willebrand factor/ADAMTS13 ratio as an indicator of venous thromboembolism risk: results from the RETROVE project.

The von Willebrand factor/ADAMTS13 ratio and shortened PFA-100 values have been associated with the risk of venous thromboembolism (VT). Our objective was to confirm the association of the VWF/ADAMTS13 ratio with VT risk and to assess the correlation between this ratio and PFA-100 values. We determined ADAMTS13 and VWF plasma levels, as well as PFA-100 values in 800 individuals (400 with VT and 400 healthy controls) from the RETROVE project. Using binary logistic regression and multivariate analyses, we evaluated the relationship between the VWF/ADAMTS13 ratio and VT risk. Quartile cut-offs of this ratio were calculated in controls, after which we estimated odds ratios (ORs) with 95% CIs. The risk of VT increased progressively with increasing quartiles of the VWF/ADAMTS13 ratio, with an OR of 4.12 (95% CI, 2.47-6.88) for the highest vs lowest quartiles in an age-adjusted analysis. When we analyzed the ROC curve for the VWF/ADAMTS13 ratio, we found similar results: we obtained three ranges of this ratio, with an increasingly progressive risk (ORs from 2.59 to 6.54). Values of the VWF/ADAMTS13 ratio correlated negatively with PFA-100 (R = - 0.5 p < 0.001). These findings indicate that the VWF/ADAMTS13 ratio is an indicator of VT risk and that a high ratio correlates negatively with PFA-100 values.