Click to enlarge. Patients with unprovoked venous thromboembolism (VTE) have a high recurrence risk and are candidates for extended anticoagulation. However, many patients stay recurrence free and are unnecessarily exposed to anticoagulants. The updated Vienna Prediction Model has been developed to discriminate patients with unprovoked VTE with a low recurrence risk from those with a high recurrence risk based on the patient’s sex, the location of VTE, and D-Dimer, and allows risk assessment of recurrence not only at 3 weeks after anticoagulation but also at several time points later than 3 weeks after anticoagulation. This updated model was presented during the 2013 Congress of the International Society on Thrombosis and Haemostasis (ISTH) held last July 2013 in Amsterdam.

In order to update the model, the investigators analysed the data set of the Austrian Study on Recurrent Venous Thromboembolism, a prospective cohort study in patients of legal age with a first VTE who had received anticoagulants for 3 to 18 months. Patients with VTE provoked by surgery, trauma, pregnancy, or female hormone intake, or with a natural inhibitor deficiency, the lupus anticoagulant, or cancer, were excluded. The study end point was recurrent symptomatic deep vein thrombosis (DVT) and/or pulmonary embolism (PE). D-Dimer levels were measured at several time points after anticoagulation and these data were linked with the patient’s sex and location of VTE. Nomograms were generated to calculate individual risk scores and cumulative recurrence rates from 3 weeks, 3, 9, 15 and 24 months on after discontinuation of anticoagulation using a dynamic landmark competing risks regression approach.

In total, 159 of 738 patients had recurrence during a mean follow-up of 6 years. The cumulative probability of recurrence was 5,5% (95% CI: 3,9%-7,2%) after 1 year and 18,4% (95% CI: 15,4%-21,4%) after 5 years. D-Dimer levels varied between patients, but did not substantially increase over time. The updated version of the Vienna prediction model has two main improvements: first of all, the model accounts for the competing risk of death or informative drop out by competing risks regression, and second, various time points of prediction are now considered rather than predicting just once after starting anticoagulation (after 3 weeks). Subdistribution hazard ratios (95% CI) dynamically changed from 3 weeks to 3, 9, 15 and 24 months from 0.29 (0.19-0.43), 0.31 (0.21-0.46), 0.37 (0.24-0.55), 0.43 (0.27-0.68) to 0.55 (0.32-0.94) in women vs. men, from 1.60 (0.84- 3.05), 1.58 (0.83-3.00), 1.54 (0.80-2.96), 1.49 (0.74-3.00) to 1.43 (0.64-3.20) in patients with proximal DVT or PE compared to distal DVT, and from 1.37 (1.23-1.66), 1.36 (1.14-1.62), 1.34 (1.14-1.58), 1.32 (1.11-1.58) to 1.29 (1.02-1.63) per doubling D-Dimer levels. Nomograms were created based on subdistribution hazard ratios from the multivariable dynamic model to predict the recurrence risk from 3 weeks, 3, 9, 15 or 24 months after anticoagulation. A web-based calculator allows risk assessment from random time points on between 3 weeks and 24 months.

In summary, the updated Vienna Prediction Model integrates patient’s sex, location of first VTE and serial D-Dimer measurements and now allows prediction of recurrent VTE at a random time point after discontinuation of oral anticoagulation. This is a major improvement on the more static model that existed before.


You can find a web-based version of the calculator at:
http://cemsiis.meduniwien.ac.at/en/kb/science-research/software/clinical-software/recurrent-vte/


Reference

Eichinger S, Heinze G, Kyrle P. D-Dimer levels over time and the risk of recurrent venous thromboembolism: An update of the Vienna Prediction model. Presented during ISTH 2013, abstract #OC 12.5.