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Synergistic effects of hypofibrinolysis and genetic and acquired risk factors on the risk of a first venous thrombosis.

ABSTRACT: BACKGROUND: Previously, we demonstrated that hypofibrinolysis, a decreased capacity to dissolve a blood clot as measured with an overall clot lysis assay, increases the risk of venous thrombosis. Here, we investigated the combined effect of hypofibrinolysis with established risk factors associated with hypercoagulability. METHODS AND FINDINGS: Fibrinolytic potential was determined with a plasma-based clot lysis assay in 2,090 patients with venous thrombosis and 2,564 control participants between 18 and 70 y of age enrolled in the Multiple Environmental and Genetic Assessment (MEGA) of risk factors for venous thrombosis study, a population-based case-control study on venous thrombosis. Participants completed a standardized questionnaire on acquired risk factors. Hypofibrinolysis alone, i.e., clot lysis time (CLT) in the fourth quartile (longest CLT) (in absence of the other risk factor of interest) increased thrombosis risk about 2-fold relative to individuals with CLT in the first quartile (shortest CLT). Oral contraceptive use in women with CLT in the first quartile gave an odds ratio (OR) of 2.6 (95% confidence interval [CI] 1.6 to 4.0), while women with hypofibrinolysis who used oral contraceptives had an over 20-fold increased risk of venous thrombosis (OR 21.8, 95% CI 10.2 to 46.7). For immobilization alone the OR was 4.3 (95% CI 3.2 to 5.8) and immobilization with hypofibrinolysis increased the risk 10.3-fold (95% CI 7.7 to 13.8). Factor V Leiden alone increased the risk 3.5-fold (95% CI 2.3 to 5.5), and hypofibrinolysis in factor V Leiden carriers gave an OR of 8.1 (95% CI 5.3 to 12.3). The combination of hypofibrinolysis and the prothrombin 20210A mutation did not synergistically increase the risk. All ORs and 95% CIs presented are relative to individuals with CLT in the first quartile and without the other risk factor of interest. CONCLUSIONS: The combination of hypofibrinolysis with oral contraceptive use, immobilization, or factor V Leiden results in a risk of venous thrombosis that exceeds the sum of the individual risks.

SUBMITTER: Meltzer ME

PROVIDER: S-EPMC2365975 | biostudies-other | 2008 May

REPOSITORIES: biostudies-other

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Project description:Background and purposeCerebral venous thrombosis (CVT) is a special cerebrovascular disease that accounts for around 0.5%-1.0% of all strokes and often occurs in younger adults. Intracranial hypertension is the most frequent symptom of acute CVT due to venous occlusion. This study aimed to ascertain the risk factors for intracranial hypertension after CVT and to investigate whether intracranial hypertension at diagnosis may affect patient outcomes.MethodsWe performed a retrospective cohort analysis of all patients treated for acute/subacute CVT at our department between 2018 and 2021. Logistic regression analysis was performed to identify potential risk factors associated with intracranial hypertension after CVT and clinical outcomes at the 6-month follow-up.ResultsA total of 293 acute/subacute CVT survivors were eligible for inclusion, with 245 patients (83.60%) experiencing concomitant intracranial hypertension at diagnosis. In the multivariable regression analysis, hereditary thrombophilia (OR 2.210, 95% CI 1.148-4.254, p = 0.018) and thrombosis location of superior sagittal sinus (SSS) and right lateral sinus (LS) (OR 4.115, 95% CI 1.880-9.010, p = 0.000) were independently associated with intracranial hypertension. 83.67% of patients with intracranial hypertension after CVT had favorable functional outcomes (mRS score, 0-2), whereas they more often had residual visual impairment (15.51% vs. 4.17%, p = 0.036) at follow-up. The risk factors for residual visual impairment were papilledema (OR 2.971, 95% CI 1.231-7.170, p = 0.015) and visual disturbances at diagnosis (OR 2.869, 95% CI 1.123-7.327, p = 0.028), thrombosis location (SSS and right LS [OR 10.811, 95% CI 4.208-27.773, p = 0.000]; SSS and left LS [OR 3.139, 95% CI 1.409-6.995, p = 0.005]), and CVT recurrence (OR 4.763, 95% CI 1.556-14.584, p = 0.006).ConclusionsIntracranial hypertension is the most common clinical symptom of acute CVT. At follow-up, patients with intracranial hypertension after CVT were more prone to develop residual visual impairment.

Project description:BackgroundRecurrent venous thromboembolism (VTE) is common. Current guidelines suggest that patients with unprovoked VTE should continue anticoagulants unless they have a high bleeding risk, whereas all others can stop. Prediction models may refine this dichotomous distinction, but existing models apply only to patients with unprovoked first thrombosis. We aimed to develop a prediction model for all patients with first VTE, either provoked or unprovoked.Methods and findingsData were used from two population-based cohorts of patients with first VTE from the Netherlands (Multiple Environment and Genetic Assessment of Risk Factors for Venous Thrombosis [MEGA] follow-up study, performed from 1994 to 2009; model derivation; n = 3,750) and from Norway (Tromsø study, performed from 1999 to 2016; model validation; n = 663). Four versions of a VTE prediction model were developed: model A (clinical, laboratory, and genetic variables), model B (clinical variables and fewer laboratory markers), model C (clinical and genetic factors), and model D (clinical variables only). The outcome measure was recurrent VTE. To determine the discriminatory power, Harrell's C-statistic was calculated. A prognostic score was assessed for each patient. Kaplan-Meier plots for the observed recurrence risks were created in quintiles of the prognostic scores. For each patient, the 2-year predicted recurrence risk was calculated. Models C and D were validated in the Tromsø study. During 19,201 person-years of follow-up (median duration 5.7 years) in the MEGA study, 507 recurrences occurred. Model A had the highest predictive capability, with a C-statistic of 0.73 (95% CI 0.71-0.76). The discriminative performance was somewhat lower in the other models, with C-statistics of 0.72 for model B, 0.70 for model C, and 0.69 for model D. Internal validation showed a minimal degree of optimism bias. Models C and D were externally validated, with C-statistics of 0.64 (95% CI 0.62-0.66) and 0.65 (95% CI 0.63-0.66), respectively. According to model C, in 2,592 patients with provoked first events, 367 (15%) patients had a predicted 2-year risk of >10%, whereas in 1,082 patients whose first event was unprovoked, 484 (45%) had a predicted 2-year risk of <10%. A limitation of both cohorts is that laboratory measurements were missing in a substantial proportion of patients, which therefore were imputed.ConclusionsThe prediction model we propose applies to patients with provoked or unprovoked first VTE-except for patients with (a history of) cancer-allows refined risk stratification, and is easily usable. For optimal individualized treatment, a management study in which bleeding risks are also taken into account is necessary.

Project description:ObjectiveThrombosis is a serious complication of systemic lupus erythematosus (SLE). We investigated whether genetic variants implicated in thrombosis pathways are associated with thrombosis among 2 ethnically diverse SLE cohorts.MethodsOur discovery cohort consisted of 1698 patients with SLE enrolled in the University of California, San Francisco, Lupus Genetics Project and our replication cohort included 1361 patients with SLE enrolled in the PROFILE cohort. Patients fulfilled American College of Rheumatology SLE criteria, and data relevant to thrombosis were available. Thirty-three single nucleotide polymorphisms (SNP) previously shown to be associated with risk of deep venous thrombosis in the general population or implicated in thrombosis pathways were genotyped and tested for association with thrombosis in bivariate allelic analyses. SNP with p < 0.1 in the bivariate analyses were further tested in multivariable logistic regression models adjusted for age, sex, disease duration, antiphospholipid antibody status, smoking, nephritis, and medications.ResultsIn the discovery cohort, 23% of patients with SLE experienced a thrombotic event. SNP in the following genes demonstrated association with thrombosis risk overall in the discovery or replication cohorts and were assessed using metaanalytic methods: factor V Leiden (FVL) rs6025 (OR 1.85, p = 0.02) and methylenetetrahydrofolate reductase (MTHFR) rs1801133 (OR 0.75, p = 0.04) in whites, and fibrinogen gamma (FGG) rs2066865 (OR 1.91, p = 0.01) in Hispanic Americans. SNP in these genes showed association with venous thrombosis risk in whites: MTHFR rs1801131 (OR 1.51, p = 0.01), MTHFR rs1801133 (OR 0.70, p = 0.04), FVL rs6025 (OR 2.69, p = 0.002), and FGG rs2066865 (OR 1.49, p = 0.02) in whites. A SNP in FGG rs2066865 (OR 2.19, p = 0.003) demonstrated association with arterial thrombosis risk in Hispanics.ConclusionOur results implicate specific genetic risk factors for thrombosis in patients with SLE and suggest that genetic risk for thrombosis differs across ethnic groups.

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Synergistic effects of hypofibrinolysis and genetic and acquired risk factors on the risk of a first venous thrombosis.

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