[show abstract][hide abstract] ABSTRACT: Circulating microparticles (MPs) may trigger a hypercoagulable state, leading to thrombotic complications. Data on their association with venous thromboembolism (VTE) are few and inconsistent.
To investigate whether or not high levels of MPs are associated with an increased risk of VTE, we carried out a case-control study on 186 patients with a first, objectively diagnosed, episode of VTE and 418 healthy controls. Plasma levels of circulating MPs were measured by flow cytometry.
Patients had higher median plasma levels of total MPs than controls (2184 per μL vs 1769 per μL, p<0.0001). The risk of VTE increased progressively with increasing MPs, with a linear dose-response effect in the log odds. Individuals with MPs above the 90th percentile of the controls' distribution (P(90) = 3263 per μL) had a 5-fold increased risk of VTE than those with MPs below the 10th percentile of controls (P(10) = 913 per μL), independently of sex, age, body mass index, thrombophilia, and plasma factor VIII levels [adjusted odds ratio: 5.30 (95%CI: 2.05-13.7)]. Using the 95th percentile of controls as cut-off (P(95) = 4120 per μL), the adjusted odds ratio was 2.20 (1.01-4.79) for individuals with MPs>P(95) compared with those having MPs ≤ P(95). After exclusion of individuals with antiphospholipid antibodies and hyperhomocysteinemia, the interaction between MPs>P(95) and thrombophilia increased the VTE risk from 1.63 (0.60-4.50) to 6.09 (1.03-36.1).
High levels of circulating MPs are a possible independent risk factor for VTE.
Thrombosis Research 09/2011; 129(5):591-7. · 3.13 Impact Factor
[show abstract][hide abstract] ABSTRACT: The clinical course of cerebral sinus-venous thrombosis (CSVT) is largely unknown because prospective studies with a long follow-up and with the goal to assess thrombosis recurrence rate and predisposing factors for recurrence are lacking.
One hundred forty-five patients with a first CSVT were followed up for a median of 6 years after discontinuation of anticoagulant treatment. End points were recurrent CSVT or other clinical manifestations of venous thromboembolism. CSVT recurred in 5 patients (3%) and other manifestations of venous thromboembolism (deep vein thrombosis of the lower limbs or pulmonary embolism) were seen in 10 additional patients (7%), for a recurrence rate of 2.03 per 100 person-years (95% confidence interval, 1.16 to 3.14) for all manifestations of venous thromboembolism and 0.53 per 100 person-years (95% confidence interval, 0.16 to 1.10) for CSVT. Nearly half of the recurrences occurred within the first year after discontinuation of anticoagulant therapy. Risk factors for recurrent venous thrombosis were male sex (adjusted hazard ratio, 9.66; 95% confidence interval, 2.86 to 32.7) and, for thromboses other than CSVT, severe thrombophilia resulting from antithrombin, protein C, protein S deficiency, anti-phospholipid antibodies, or combined abnormalities (adjusted hazard ratio, 4.71; 95% confidence interval, 1.34 to 16.5).
The risk of recurrent CSVT is low and is higher in the first year after discontinuation of anticoagulant treatment and among men. Mild thrombophilia abnormalities are not associated with recurrent CSVT, but severe thrombophilia entails an increased risk of deep vein thrombosis of the lower limbs or pulmonary embolism.