Lisette van Dam

Chapter 3 44 to select the optimal scenario. In the Netherlands, interventions are considered cost-effective up to 20,000 to 80,000 euros per quality-adjusted life years (QALY). 34 Assuming a quality-adjusted life expectancy of about 25 years in our population, these thresholds translates to 0.5 to 2 million euros per prevented death. 35,36 Microsoft Excel (2016) was used to perform all analyses. RESULTS Study patients The Theia study flowchart was described in previous publications from the Theia study. 13,17 A total of 234 patients were included in this analysis, excluding 71 patients for the following reasons: therapeutic anticoagulant treatment ≥ 48 hours prior to presentation (n=68), inconclusive MRDTI because of artefacts (n=1), MRDTI not performed because of claustrophobia (n=1) and protocol deviation (n=1). The baseline characteristics of the study population are shown in Table 2 . The DVT prevalence (baseline and 3-months follow-up combined) was 43% (100/234). The diagnostic accuracy of each test, depending on preceding tests, are reported in Table 3 . Table 2. Baseline characteristics of 234 patients with suspected recurrent ipsilateral deep vein thrombosis included in this analysis. Characteristics Data Mean age (+/- SD) – years 56 (16) Male – no (%) 110 (47) Median duration of complaints (IQR) – days 4 (2-7) More than 1 prior VTE episode – no (%) 50 (21) Mean time since the last DVT episode (+/- SD) – years 6.9 (9.2) Active malignancy – no (%) 10 (4.3) Immobility for > 3 days or recent long travel > 6 hours in the past 4 weeks – no (%) 15 (6.4) Trauma/surgery during the past 4 weeks – no (%) 9 (3.8) Hormone (replacement) therapy – no (%) 5 (2.1) Known genetic thrombophilia – no (%) 19 (8.1)