https://journal.chestnet.org/article/S0012-3692(12)60129-9/pdf

Antithrombotic therapy for VTE disease: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines.

https://www.healthcare.uiowa.edu/familymedicine/fpinfo/Docs/Chest%20Rx%20VTE%20Feb%202016.pdf

Antithrombotic Therapy for VTE Disease: CHEST Guideline and Expert Panel Report

https://www.uky.edu/~achan2/pics/med/pe-tx-chest.pdf

Antithrombotic therapy for venous thromboembolic disease: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition).

Venous thromboembolism (VTE) is categorized by the U.S. Surgeon General as a major public health problem. VTE is relatively common and associated with reduced survival and substantial health-care costs, and recurs frequently. VTE is a complex (multifactorial) disease, involving interactions between acquired or inherited predispositions to thrombosis and VTE risk factors, including increasing patient age and obesity, hospitalization for surgery or acute illness, nursing-home confinement, active cancer, trauma or fracture, immobility or leg paresis, superficial vein thrombosis, and, in women, pregnancy and puerperium, oral contraception, and hormone therapy. Although independent VTE risk factors and predictors of VTE recurrence have been identified, and effective primary and secondary prophylaxis is available, the occurrence of VTE seems to be relatively constant, or even increasing.

The Epidemiology of Venous Thromboembolism

Oral Anticoagulants: Mechanism of Action, Clinical Effectiveness, and Optimal Therapeutic Range

Background A high plasma level of factor VIII is a risk factor for venous thromboembolism. We evaluated the risk of a recurrence of thrombosis after an initial episode of spontaneous venous thromboembolism among patients with high plasma levels of factor VIII. Methods We studied 360 patients for an average follow-up period of 30 months after a first episode of venous thromboembolism and discontinuation of oral anticoagulants. Patients who had recurrent or secondary venous thromboembolism, a congenital deficiency of an anticoagulant, the lupus anticoagulant, hyperhomocysteinemia, cancer, or a requirement for long-term treatment with antithrombotic drugs or who were pregnant were excluded. The end point was objectively documented, symptomatic recurrent venous thromboembolism. Results Recurrent venous thromboembolism developed in 38 of the 360 patients (10.6 percent). Patients with recurrence had higher mean (±SD) plasma levels of factor VIII than those without recurrence (182±66 vs. 157±54 IU per deciliter,...

https://www.nejm.org/doi/pdf/10.1056/NEJM200008173430702

High plasma levels of factor viii and the risk of recurrent venous thromboembolism

The post-thrombotic syndrome: risk factors and impact on the course of thrombotic disease.

Hyperhomocysteinemia is a risk factor of venous thromboembolism. The risk of recurrence in patients with hyperhomocysteinemia is unknown, and the optimal therapy for these patients after acute venous thromboembolism is uncertain. In a multicenter study, 264 patients with an objectively documented single episode of idiopathic venous thromboembolism were prospectively followed after discontinuation of oral anticoagulants. Patients were classified as hyperhomocysteinemic if their homocysteine levels exceeded the 95th percentile of the controls. The outcome events studied were objectively confirmed deep-vein thrombosis and/or pulmonary embolism. Homocysteine levels were elevated in 66 patients (25%) and normal in 198 patients (75%). Recurrent venous thromboembolism occurred in 12 of 66 patients with hyperhomocysteinemia (18.2%) and in 16 of 198 patients without hyperhomocysteinemia (8.1%). The cumulative probability of recurrence 24 months after discontinuation of oral anti-coagulants was 19.2 percent (95 percent confidence interval 8.7-27) in patients with hyperhomocysteinemia and was 6.3 percent (95 percent confidence interval 2.4-10.1; p = 0.001) in those without hyperhomocysteinemia. The relative risk of recurrent thrombosis was higher in patients with hyperhomocysteinemia [RR 2.7 (1.3-5.8), p = 0.009]. Patients with hyperhomocysteinemia are at high risk of recurrent venous thromboembolism. The high prevalence of hyperhomocysteinemia in thrombosis patients together with the increased risk of recurrence warrants extended patient screening. The impact on the risk of recurrence of prolonged anticoagulation, supplementation of folate and vitamin B12 , or both have to be investigated.

Hyperhomocysteinemia Is a Risk Factor of Recurrent Venous Thromboembolism

—A genetic variation in the prothrombin gene, the G→A transition at nucleotide 20210, is a risk factor for venous thrombosis in heterozygotes and is associated with increased prothrombin activity. The homozygous phenotype and the extent of thrombin generation in heterozygous and homozygous subjects are unknown. We investigated a family that included 2 homozygous and 5 heterozygous carriers of the 20210 A allele. The homozygous propositus and his presumably heterozygous father suffered from deep-vein thrombosis. His presumably heterozygous mother and his homozygous sister had recurrent phlebitis at a young age. The remaining 5 affected family members are still asymptomatic. We studied thrombin generation in the family and in 22 unrelated carriers of the 20210 A allele by measuring (1) prothrombin fragment F1+2 (F1+2) as an index of ongoing thrombin generation and (2) the endogenous thrombin potential (ETP) as an index of the possible thrombin-forming capacity. Their F1+2 levels were not different from those of age-matched controls, and thus, ongoing hemostatic system activation was not detectable. A significantly increased ETP was found in the heterozygous carriers of the 20210A allele compared with the controls (527.8±114.9 versus 387±50.1 nmol/L · min, P <0.0001). In the 2 homozygotes, the ETP was almost twice (639 and 751 nmol/L · min, respectively) as high as in the controls. We conclude that homozygosity for the G20210A mutation in the prothrombin gene is associated with a severe, albeit more benign, thrombotic diathesis compared with homozygosity for deficiencies of antithrombin, protein C, or protein S. In carriers of the 20210 A allele, the pathomechanisms leading to thrombosis should be sought in the higher amounts of thrombin that may be formed once thrombin generation is triggered, rather than in ongoing thrombin generation in vivo.

Clinical Studies and Thrombin Generation in Patients Homozygous or Heterozygous for the G20210A Mutation in the Prothrombin Gene

Background: In patients with a first symptomatic pulmonary embolism (PE), the risk of recurrence is unknown. We therefore investigated the risk of recurrence among patients with spontaneous symptomatic PE and among those with deep vein thrombosis (DVT) without symptoms of PE. Methods: After discontinuation of secondary thromboprophylaxis for a first venous thromboembolism (VTE), we prospectively observed 436 patients for an average of 30 months. Patients with secondary VTE, natural inhibitor deficiencies, lupus anticoagulant, cancer, long-term antithrombotic therapy, vena cava filters, or pregnancy were excluded. The study outcome was objectively documented recurrent symptomatic VTE. Results: Recurrent VTE was seen among 28 (17.3%) of 162 patients with symptomatic PE and among 26 (9.5%) of 274 patients with DVT without symptoms of PE. Compared with patients with DVT, the relative risk of recurrent VTE among patients with symptomatic PE was 2.2 (95% confidence interval, 1.3-3.7; P = .005). The relative risk was not affected by age, sex, presence of factor V Leiden or prothrombin G20210A, hyperhomocysteinemia, or high factor VIII levels. Compared with patients with DVT without symptoms of PE, patients with symptomatic PE had an adjusted relative risk of PE at recurrence of 4.0 (95% confidence interval, 1.3-12.3;P=.03). Conclusion: Patients with a first symptomatic PE not only have a higher risk of recurrent VTE than those with DVT without symptoms of PE, but are also at high risk of symptomatic PE at recurrence. Arch Intern Med. 2004;164:92-96

https://jamanetwork.com/journals/jamainternalmedicine/articlepdf/216461/ioi20610.pdf

Milena Stain

Papers

High plasma levels of factor viii and the risk of recurrent venous thromboembolism

The post-thrombotic syndrome: risk factors and impact on the course of thrombotic disease.

Hyperhomocysteinemia Is a Risk Factor of Recurrent Venous Thromboembolism

Clinical Studies and Thrombin Generation in Patients Homozygous or Heterozygous for the G20210A Mutation in the Prothrombin Gene

Symptomatic Pulmonary Embolism and the Risk of Recurrent Venous Thromboembolism