African-Caribbean ethnicity is associated with an increased risk of both first and recurrent venous thromboembolism (VTE). The aim of this study was to evaluate thrombin generation in African-Caribbeans compared with whites in patients with deep vein thrombosis (DVT) and healthy volunteers. Thrombin generation was measured in a case-control study of 80 patients who had completed anticoagulation therapy for a first DVT (50 white and 30 African-Caribbean) and 66 controls. Peak thrombin with and without thrombomodulin was significantly higher in African-Caribbeans with DVT compared with whites with DVT (P < 0.001 for both comparisons) and African-Caribbean controls (P < 0.001, 0.003, respectively). Endogenous thrombin potential (ETP) with and without thrombomodulin was significantly higher in African-Caribbeans with DVT than whites with DVT (P ≤ 0.001 for both comparisons). Maximum velocity and ETP ratio were increased in African-Caribbeans with DVT compared with whites with DVT (P < 0.001 and 0.030, respectively) and African-Caribbean controls (P < 0.001 and 0.019, respectively). Within the control group, peak thrombin was significantly increased in African-Caribbeans compared with whites (P = 0.017). ETP, peak thrombin with thrombomodulin and maximum velocity were also increased in African-Caribbeans compared with white controls (P = 0.045 for all comparisons). African-Caribbeans with DVT had significantly higher factor VIII levels compared with whites with DVT and controls. African-Caribbean ethnicity confers a hypercoagulable state as measured by thrombin generation. This supports epidemiological findings of increased risk of first and recurrent VTE. Thrombin generation requires adjustment for ethnicity in studies undertaken in ethnically diverse populations.
SummaryPost-thrombotic syndrome (PTS) is the most common complication of deep vein thrombosis (DVT). Current preventative strategies are limited to the daily wear of graduated compression stockings (GCS). The aim of this study was to evaluate early predictors of PTS. One hundred and twentytwo consecutive patients with a first DVT were prospectively recruited from diagnosis and followed for up to 6 months post-end of anticoagulation. D-dimer was measured in 107 participants at presentation and Villalta scale was evaluated in 70 participants at a median of 2 weeks following diagnosis. PTS developed in 51Á6% of participants. GCS were obtained by 78Á1% of participants, with 33Á7% reporting daily wear at the end of follow-up. Mean early Villalta scale was significantly higher in those with PTS (8Á1 AE 3Á7) compared to those without (2Á6 AE 2Á7, P < 0Á001). Median D-dimer was significantly higher in those with PTS [3260 ng/ml, interquartile range (IQR) 820-8000 ng/ml] compared to those without (1540 ng/ml, IQR 810-2520 ng/ml, P < 0Á001). The adjusted odds ratio for every one point increase in early Villalta scale was 1Á78 [95% confidence interval (CI), 1Á19-2Á64; P = 0Á005] and for D-dimer >1910 ng/ml it was 2Á71 (95% CI, 1Á05-7Á03; P = 0Á04). These markers could enable targeted counselling regarding GCS for those at high risk of PTS.
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