ALBERT

Description: Background Together with clinical decision rules, D-dimer testing has long been the mainstay of diagnostic work-up of suspected deep vein thrombosis (DVT). Advantages of D-dimer measurement include wide availability, low costs and high sensitivity. Age-adjusted D-dimer cut-off values have been suggested to improve specificity of D-dimer testing, defining a positive D-dimer as age multiplied by 0.01 mg/L at or over fifty years of age. Age-adjusted cut-off values have been found to increase specificity without compromising safety in the setting of acute pulmonary embolism, but have not been extensively evaluated in DVT. In this study, we aimed to evaluate and compare the diagnostic performance of fixed versus age-adjusted D-dimer thresholds in patients with suspected DVT, as a stand-alone test or in combination with pre-test probability assessment. Methods We included 973 consecutive outpatients referred to Østfold Hospital, Norway, with suspected first or recurrent lower extremity DVT, between 2015 and 2017. STA®-Liatest® Plus D-Dimer assay was performed and Wells clinical score assessed in all patients. Patients with positive fixed D-dimer (≥0.5 mg/L) were referred for whole-leg compression ultrasonography (CUS), whereas patients with negative D-dimer were not, irrespective of the clinical pre-test probability. Failure rate was defined as patients with negative D-dimer at baseline remaining untreated and diagnosed with symptomatic venous thromboembolism during 3-month follow-up. We compared diagnostic indices of both D-dimer thresholds with or without initial pre-test probability assessment. Results DVT was diagnosed in 177 out of 973 patients (18%).The fixed D-dimer cut-off was associated with a sensitivity of 99.4% (95% CI 96.9 to 99.9%) for one diagnostic failure (0.3%) (not adjudicated as of print). Adding the Wells score would have detected this one case at a cost of 90 additional CUS examinations. Age-adjusted D-dimer as a stand-alone test was associated with 6 diagnostic failures (1.5%) for a sensitivity of 96.6% (95% CI 92.8 to 98.8%). Age-adjusted D-dimer combined with Wells score yielded a sensitivity of 99.4% (95% CI 96.9 to 99.9%), with one diagnostic failure (0.4%) and 714 patients referred for CUS. Conclusion Our results suggest that the fixed D-dimer as a stand-alone test without Wells score is a safe and efficient diagnostic strategy. Combining age-adjusted D-dimer with Wells score was equally safe, but was not associated with a lower number of necessary CUS examinations. Disclosures Fronas: Bayer AG: Other: Bayer AG contributed with financial support in conducting the study; South-Eastern Norway Regional Health Authority: Other: Grant in conducting the study. Tøvik Jørgensen:Bayer AG: Other: Bayer AG contributed with financial support in conducting the study; South-Eastern Norway Regional Health Authority: Other: Grant for conducting the study. Ghanima:Bayer, BMS, Novartis: Research Funding; Amgen, Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees.

Description: The diagnosis of recurrent ipsilateral deep vein thrombosis (DVT) is challenging, because persistent intravascular abnormalities after previous DVT often hinder a diagnosis by compression ultrasonography. Magnetic resonance direct thrombus imaging (MRDTI), a technique without intravenous contrast and with a 10-minute acquisition time, has been shown to accurately distinguish acute recurrent DVT from chronic thrombotic remains. We have evaluated the safety of MRDTI as the sole test for excluding recurrent ipsilateral DVT. The Theia Study was a prospective, international, multicenter, diagnostic management study involving patients with clinically suspected acute recurrent ipsilateral DVT. Treatment of the patients was managed according to the result of the MRDTI, performed within 24 hours of study inclusion. The primary outcome was the 3-month incidence of venous thromboembolism (VTE) after a MRDTI negative for DVT. The secondary outcome was the interobserver agreement on the MRDTI readings. An independent committee adjudicated all end points. Three hundred five patients were included. The baseline prevalence of recurrent DVT was 38%; superficial thrombophlebitis was diagnosed in 4.6%. The primary outcome occurred in 2 of 119 (1.7%; 95% confidence interval [CI], 0.20-5.9) patients with MRDTI negative for DVT and thrombophlebitis, who were not treated with any anticoagulant during follow-up; neither of these recurrences was fatal. The incidence of recurrent VTE in all patients with MRDTI negative for DVT was 1.1% (95% CI, 0.13%-3.8%). The agreement between initial local and post hoc central reading of the MRDTI images was excellent (κ statistic, 0.91). The incidence of VTE recurrence after negative MRDTI was low, and MRDTI proved to be a feasible and reproducible diagnostic test. This trial was registered at www.clinicaltrials.gov as #NCT02262052.