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The study gives a survey of literature on obstetric aspects of hereditary thrombophilias e.i. factor V Leiden, prothrombin gene 20210A mutation, antithrombin III deficiency, protein C/protein S deficiency, and hyperhomocysteinemia. All types of thrombophilia cause similar pathomorphological changes in placenta and decidua (high number of infarcts and microclots, decidual vasculopathia) as well as insufficient invasion of cytotrophoblast in spiral arteries. The study also discusses prophylactic rules: application of low molecular weight heparin and non-fractionated heparin in prophylaxis and in hyperhomocysteinemia application of folic acid.
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PMID:[Obstetric aspects of hereditary thrombophilias: epidemiology, complications and prophylaxis]. 1293 69

Until recently the laboratory diagnosis of thrombophilia consisted on investigation of the plasmatic anticoagulant pathways and the search for dysfibrinogenemia and antiphospholipid antibodies/lupus anticoagulants. More recently, the laboratory investigation has been expanded by including activated protein C (APC) resistance, due or not to the presence of the factor V Leiden mutation; hyperprothrombinemia, due to the presence of the prothrombin mutation G20210A and hyperhomocysteinemia, due to impairment of the relevant metabolic pathway because of enzymatic and/or vitamin deficiency. Testing for thrombophilia may be useful for many reasons. First, the results of testing may provide valuable information to assess the risk of recurrence in the proband. Second, testing family members is useful for prophylactic and diagnostic purposes. Third, the identification of patients bearing combined defect helps to identify those at increased risk for thrombosis. Testing is recommended for patients with a past history of thrombosis and should be extended to their first-degree family members. Since most of the tests are not reliable during anticoagulation, it is preferable to postpone laboratory testing until after discontinuation of the treatment. Whenever possible testing should be performed by means of functional assays. DNA analysis is required for the prothrombin mutation G20210A. Laboratory diagnosis for antiphospholipid antibodies/lupus anticoagulant should be performed by a combination of tests including phospholipid-dependent clotting assays and solid phase anticardiolipin antibodies. Hyperhomocysteinemia may be assessed by high-pressure liquid chromatography methods, or by fluorescence polarization immunoassays.
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PMID:Laboratory diagnosis of thrombophilic states: where do we stand? 1367 50

We investigated the association between inherited and acquired maternal thrombophilias and adverse pregnancy events. A cohort of 491 patients with a history of adverse pregnancy outcomes was evaluated for activated protein C resistance, factor V Leiden and prothrombin G20210A mutations, hyperhomocysteinemia, deficiencies of antithrombin, protein C and S and both anticardiolipin antibodies and lupus anticoagulants. The study had an 80% power to detect a 15% difference in the prevalence of thrombophilia for 1(st) trimester loss. In our high-risk cohort the presence of 1 maternal thrombophilia or more than one thrombophilia were found to be protective of recurrent losses at < 10 weeks (1 thrombophilia: OR: 0.55, 95% CI: 0.33-0.92; > 1 thrombophilia: OR: 0.48, 95%CI:0.29-0.78). In contrast, the presence of maternal thrombophilia(s) was modestly associated with an increased risk of losses > 10 weeks (1 thrombophilia: OR:1.76, 95%CI: 1.05-2.94, >1 thrombophilia: OR:1.66, 95%CI:1.03-2.68). Women who experienced only euploid losses were not more likely to have an identified thrombophilia than women who experienced only aneuploid losses (OR 1.03; 0.38-2.75). The presence of maternal thrombophilia was associated with an increased risk of fetal loss after 14 weeks, fetal growth restriction, abruption and preeclampsia. There was a significant "dose-dependent" increase in the risk of abruption (OR:3.60, 95%CI: 1.43-9.09) and preeclampsia (OR:3.21, 95%CI:1.20-8.58). In conclusion, these data indicate maternal thrombophilias are not associated with pregnancy wastage prior to 10 weeks of gestation.
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PMID:Maternal thrombophilias are not associated with early pregnancy loss. 1496 Nov 56

Thrombophilia is characterized by clinical tendency to thrombosis or molecular abnomalities of hemostasis that predisposes to thromboembolic disease. Hereditary thrombophilia may be due to antithrombin deficiency, or protein C or protein S deficiency. More recently, other molecular abnormalities have been described: activated protein C resistance due to factor V Leiden, G 20210 A polymorphism on the prothrombin gene, increased factor VIII plasma levels or hyperhomocysteinemia. Acquired thrombophilia is frequently associated with the antiphospholipid syndrome characterized by thrombosis and presence of lupus anticoagulant or phospholipid-binding antibodies. In some cases, no molecular abnormality is found despite recurrent thrombosis observed in patient and his/her family. This situation can be considered as clinical thrombophilia.
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PMID:[Definition of thrombophilia]. 1502 78

Selected blood tests may be useful in the diagnosis of venous thromboembolism (VTE), or in the identification of a congenital or acquired defect associated with the development of VTE. Several studies have shown the D-dimer assay to have a high negative predictive value but poor specificity when used in the detection of VTE. Yet in the emergency room setting, the D-dimer test may be useful if a detailed risk factor analysis for each patient is included in the diagnosis. The presence of such genetic thrombophilia markers as factor V Leiden, prothrombin 20210A mutation, and antiphospholipid antibodies significantly increases a patient's risk of a thrombotic event. The relative risk of thrombosis in factor V heterozygotes is at least 3 times higher than in the general population, whereas the increased risk of thrombosis in homozygotes is estimated to be 50- to 80-fold greater than those without the defect. Thromboembolic events are reported in approximately one third of antiphospholipid-positive patients. Other markers such as hyperhomocysteinemia and deficiencies of antithrombin, protein C, or protein S, when combined with the previous mutations, significantly increase a patient's risk of a thrombotic event. We feel that it is important to identify these ultra-high-risk patients to provide adequate counseling about the risk of thrombosis before elective surgical procedures. Often, lifelong anticoagulation may be needed as these patients and family members may need testing before taking birth control pills or hormonal replacement.
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PMID:Laboratory markers in the diagnosis of venous thromboembolism. 1505 62

Venous thromboembolism (VTE) is one of the most frequent multifactorial diseases. It manifests clinically by deep vein thrombosis (DVT) and pulmonary embolism (PE) leading to death in about 6%. It is important to emphasize, that 50% of the patients do not present any symptoms. The prevalence is influenced by age and ethnics. Both, hereditary (Factor V Leiden, G20210A prothrombin gene mutation, deficiencies of protein C, S or antithrombin) and acquired risk factors (estrogen replacement, cancer, cardiovascular disease, surgery, trauma, immobility, use of central venous catheters, autoimmune disease such as anti-phospholipid syndrome) contribute to VTE. The risk increases dramatically by the addition of hyperhomocysteinemia or the combination of several risk factors. Since VTE is a dynamic process able to manifest clinically or to resolve completely, the identification of persons at increased risk is mainly important for early diagnosis and treatment. The diagnostic strategy including clinical scores and laboratory tests (D-dimer measurement) as initial steps to confirm the suspicion of VTE may exclude patients who do not need further, sometimes invasive imaging tests (venography, compression ultrasonography combined or not combined with colour Doppler imaging, magnetic resonance imaging). Laboratory tests for suspected inherited thrombophilia should be performed six months after clinical presentation.
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PMID:Epidemiology, etiology and diagnosis of venous thrombosis. 1509 18

Up to date several hereditary disorders have been identified as prothrombic risk factors. The most common inherited thrombotic disorders include activated protein C resistance (factor V Leiden), prothrombin G20210A mutation, hyperhomocysteinemia, deficiencies of protein C, protein S, antithrombin III, and thrombomodulin. This article focuses on the clinical and the laboratory aspects of some of the inherited venous thrombotic disorders including the factor V Leiden, prothrombin G20210A mutation and protein S deficiency.
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PMID:[Genetic risk factors of venous thromboembolism]. 1510 Sep 7

The annual incidence of diagnosed venous thromboembolism (VTE) is 1 to 2 events per 1000 of the general population. VTE is very uncommon before age 20 years and, after 40 years of age, the incidence about doubles with each decade. Over half of episodes of VTE are deep vein thrombosis (DVT), and three quarters are first episodes. The incidence of VTE is similar in men and women and lower in Asians than it is in Caucasians or Africans. Hereditary risk factors include the factor V Leiden mutation; the G20210A prothrombin gene mutation; and deficiencies of protein C, protein S, and antithrombin. Hyperhomocysteinemia and elevated levels of factors I, VIII and XI, which may be hereditary and/or acquired, are also risk factors. Acquired risk factors include malignancy, hospitalization, surgery, venous trauma, immobilization, estrogen therapy, pregnancy, and the antiphospholipid antibodies. Risk factors for a first episode of VTE are generally also risk factors for recurrence, although the associated relative risk for thrombosis may differ for a first and subsequent event.
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PMID:Epidemiology of venous thromboembolism. 1519 10

The etiology of venous thromboembolic disease has been the subject of several recent discoveries, particularly on genetic predisposing factors. The laboratory investigation that may help to evaluate the risk for individual patients includes the measurements of coagulation inhibitors (antithrombin, protein C, and protein S) in plasma assays, the search for the factor V Leiden mutation by the plasma activated protein C resistance test (always to be confirmed by DNA analysis when abnormal), and the search for the prothrombin gene mutation by DNA analysis. Among acquired abnormalities, the most frequently involved are phospholipid-dependent autoantibodies associated or not with a subset of antibodies having an anticoagulant effect in vitro (lupus anticoagulant). Other coagulation abnormalities such as increased FVIII, FIX, or FXI levels or hyperhomocysteinemia have been suggested to be risk factors for thrombosis, although additional studies are required to definitively assess their role.
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PMID:Venous thromboembolic disease: risk factors and laboratory investigation. 1519 17

The purpose of the present study was to determine whether using an extended panel of laboratory tests increases the detection of a hypercoagulable state in patients with ocular thromboses. Twenty consecutive patients with ocular thromboses (vein, artery, or choriocapillaris occlusions) underwent testing for activated protein C resistance/factor V Leiden, prothrombin G20210A, lupus anticoagulant, anticardiolipin antibodies, hyperhomocysteinemia, and deficiencies of protein C, protein S, and antithrombin. For each patient, we selected two age-matched and gender-matched individuals without ocular thromboses as controls. Sixteen of the 20 patients (80%) had one or more laboratory tests that supported a hypercoagulable condition. Prothrombin G20210A (P < 0.02) and hyperhomocysteinemia (P < 0.0006) were significantly more frequent in ocular thrombosis patients compared with controls. The most common condition was antiphospholipid antibody syndrome, present in 40% of patients (confirmed by repeat testing at least 6 weeks later), but this did not reach statistical significance compared with the controls. No patients with ocular thromboses had hereditary abnormalities of protein S, protein C, or antithrombin. In conclusion, an extended panel of laboratory tests improved the detection of a hypercoagulable state in ocular thromboses. Testing for homocysteine, antiphospholipid antibodies, and the prothrombin G20210A mutation should be considered in patients with ocular thromboses.
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PMID:Prothrombin gene mutation G20210A, homocysteine, antiphospholipid antibodies and other hypercoagulable states in ocular thrombosis. 1520 87


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