Summary. Background/objectives: We prospectively measured change in quality of life (QOL) during the 2 years after a diagnosis of deep vein thrombosis (DVT) and evaluated determinants of QOL, including development of the postthrombotic syndrome (PTS). Patients/methods: Consecutive patients with acute DVT were recruited from 2001 to 2004 at eight hospitals in Canada. At study visits at baseline, and 1, 4, 8, 12 and 24 months, clinical data were collected, standardized PTS assessments were performed, and QOL questionnaires were self-completed. Generic QOL was measured using the Short-Form Health Survey-36 (SF-36) questionnaire. Venous disease-specific QOL was measured using the Venous Insufficiency Epidemiological and Economic Study (VEINES)-QOL/ Sym questionnaire. The change in QOL scores over a 2-year follow-up was assessed. The influence of PTS and other characteristics on QOL at 2 years was evaluated using multivariable regression analyses. Results: Among the 387 patients recruited, the average age was 56 years, two-thirds were outpatients, and 60% had proximal DVT. The cumulative incidence of PTS was 47%. On average, QOL scores improved during follow-up. However, patients who developed PTS had lower scores at all visits and significantly less improvement in QOL over time (P-values for PTS*time interaction were 0.001, 0.012, 0.014 and 0.006 for PCS, MCS, VEINES-QOL and VEINES-Sym). Multivariable regression analyses showed that PTS (P < 0.0001), age (P = 0.0009), proximal DVT (P = 0.01) and inpatient status (P = 0.04) independently predicted 2-year SF-36 PCS scores. PTS alone independently predicted 2-year VEINES-QOL (P < 0.0001) and VEINESSym (P < 0.0001) scores. Conclusions: Development of PTS is the principal determinant of health-related QOL 2 years after DVT. Our study provides prognostic information on patientreported outcomes after DVT and emphasizes the need for effective prevention and treatment of the PTS.

SummaryThe post-thrombotic syndrome (PTS) occurs frequently after deep venous thrombosis (DVT) despite appropriate anticoagulant therapy. A close relationship between inflammation and thrombosis exists. While the inflammatory process at the time of DVT appears to improve thrombus resolution, it may promote destruction of venous valves, valvular reflux and subsequent development of PTS. We prospectively evaluated the association between levels of four cytokines (IL-6, IL-8, IL-10 and MCP-1), two adhesion molecules (ICAM-1 and VCAM-1) and the development of PTS in a well-defined cohort of patients with DVT. The study population consisted of 387 patients with objectively diagnosed symptomatic DVT who were followed for two years to determine the incidence of PTS. At the end of follow-up, plasma samples frozen at the four-month visit in 307 study patients were thawed and analyzed for the above inflammatory markers using the Luminex beads technology. Mean levels of IL-6 were significantly higher in patients with PTS compared to patients without PTS (7.35 pg/ml ± 14.26 [SD] vs. 4.60 pg/ml ± 4.90;p=0.03). Logistic regression analyses showed significant associations between PTS and levels above vs. below the median of IL-6 [odds ratio (OR) 1.66; 95% confidence interval (CI) 1.05, 2.62 (p=0.03)] and ICAM-1 [OR 1.63; 95% CI 1.03, 2.58 (p=0.04)]. None of the other markers showed any association with PTS. Our study suggests the presence of significant associations between markers of inflammation such as IL-6 and ICAM-1 and the development of PTS. Further work is needed to evaluate this relationship and to analyse other candidate markers that could be implicated etiologically in the association between DVT and PTS. If confirmed, this could lead to identification of new therapeutic targets for preventing PTS after DVT.

Background: The post-thrombotic syndrome (PTS) occurs frequently after deep vein thrombosis (DVT) despite appropriate anticoagulant therapy. A close relationship between inflammation and thrombosis exists. While the inflammatory process at the time of DVT appears to improve thrombus resolution, it may promote destruction of venous valves, valvular reflux and subsequent development of PTS. Objective: We prospectively evaluated the association between levels of four cytokines (IL-6, IL-8, IL-10 and MCP-1), two adhesion molecules (ICAM-1 and VCAM-1) and the development of PTS in a well-defined cohort of patients with DVT. Methods: The study population consisted of 387 patients with objectively diagnosed symptomatic DVT who participated in the Venous Thrombosis Outcomes (VETO) Study and were followed for two years to determine the incidence of PTS. For this substudy, plasma samples frozen at the 4 month visit in 307 study patients who consented to provide blood samples were thawed and analyzed for the above inflammatory markers using the Luminex beads technology. Associations between marker levels and development of the PTS during follow-up were evaluated. Results: Mean levels of IL-6 were significantly higher in patients with PTS compared to patients without PTS (7.35 pg/ml ± 14.26 vs. 4.60 pg/ml ± 4.90;p=0.03). Logistic regression analyses showed significant associations between PTS and levels above vs. below the median of IL-6 (OR 1.66; 95% CI 1.05, 2.62 (p=0.03)) and ICAM-1 (OR 1.63; 95% CI 1.03, 2.58 (p=0.04)). None of the other markers showed any association with PTS. Conclusion: Our study suggests the presence of significant associations between markers of inflammation such as IL-6 and ICAM-1 and the development of PTS. Further work is needed to evaluate this relationship and to analyze other candidate markers that could be implicated etiologically in the association between DVT and PTS. If confirmed, this could lead to identification of new therapeutic targets for preventing PTS after DVT.

BackgroundPost thrombotic syndrome (PTS) is a burdensome and costly complication of deep venous thrombosis (DVT) that develops in 20–40% of patients within 1–2 years after symptomatic DVT. Affected patients have chronic leg pain and swelling and may develop ulcers. Venous valve disruption from the thrombus itself or thrombus-associated mediators of inflammation is considered to be a key initiating event for the development of venous hypertension that often underlies PTS. As existing treatments for PTS are extremely limited, strategies that focus on preventing the development of PTS in patients with DVT are more likely to be effective and cost-effective in reducing its burden. Elastic compression stockings (ECS) could be helpful in preventing PTS; however, data on their effectiveness are scarce and conflicting.Methods/DesignThe SOX Trial is a randomized, allocation concealed, double-blind multicenter clinical trial. The objective of the study is to evaluate ECS to prevent PTS. A total of 800 patients with proximal DVT will be randomized to one of 2 treatment groups: ECS or placebo (inactive) stockings worn on the DVT-affected leg daily for 2 years. The primary outcome is the incidence of PTS during follow-up. Secondary outcomes are severity of PTS, venous thromboembolism (VTE) recurrence, death from VTE, quality of life and cost-effectiveness. Outcomes will be evaluated during 6 clinic visits and 2 telephone follow ups. At baseline, 1 and 6 months, blood samples will be obtained to evaluate the role of inflammatory mediators and genetic markers of thrombophilia in the development of PTS (Bio-SOX substudy).DiscussionThe SOX Trial will be the largest study and the first with a placebo control to evaluate the effectiveness of ECS to prevent PTS. It is designed to provide definitive data on the effects of ECS on the occurrence and severity of PTS, as well as DVT recurrence, cost-effectiveness and quality of life. This study will also prospectively evaluate the predictive role of biomarkers that are reflective of putative underlying pathophysiological mechanisms in the development of clinical PTS. As such, our results will impact directly on the care of patients with DVT.Trial RegistrationNCT00143598 and ISRCTN71334751

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