Seminars in vascular medicine
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Inherited thrombophilia has been reported to be associated with an increased risk for complications of pregnancy, including venous thromboembolism (VTE) as well as preeclampsia (PEC), fetal loss (FL), fetal growth retardation (FGR), and abruptio placentae (AP), the latter probably due to inadequate placental perfusion. The estimate of risk largely depends on the kind of thrombophilia and on the criteria applied for the selection of the patients, producing in some cases contradictory results. Convincing evidence is available that deficiency of antithrombin III (AT), protein C (PC), and protein S (PS) is a risk factor for VTE and late FL. ⋯ However, the absolute risk for VTE during pregnancy and puerperium is between 1 and 3%, in comparison with the baseline risk of 0.08%. Antithrombotic prophylaxis with subcutaneous heparin is warranted during puerperium in all women with thrombophilia and throughout all pregnancy in women at higher risk (AT deficiency, homozygosity for factor VLeiden, and perhaps PC and PS deficiencies); treatment with subcutaneous heparin for prevention of FL among women with thombophilia is under investigation. Presence of inherited thrombophilia increases the risk for VTE due to oral contraceptives up to an absolute risk of 3 per 1000 person-years, in comparison with the baseline risk of 3 to 6 per 10000 person-years; the risk is further increased by first usage, the use of preparations containing third-generation progestins, and thrombophilia due to AT, PC, and PS deficiency as well as homozygous factor V (Leiden) and combined defects.
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Since the introduction of oral contraceptives, their use has been associated with an increased risk of both venous and arterial thrombosis. Pulmonary embolism, myocardial infarction, and stroke are serious disorders with a considerable risk of mortality. Because worldwide over 100 million women use oral contraceptives, issues of drug safety are of great importance. ⋯ For stroke and peripheral arterial disease no difference in risk was found between second and third generation oral contraceptives. For myocardial infarction study results are conflicting, and a small benefit of third- over second-generation oral contraceptives cannot be ruled out. However, this is unlikely to counterbalance the adverse effect of third generation contraceptives on venous thrombosis.
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Pulmonary angiography is the gold standard for diagnosis of segmental pulmonary embolism, but no longer for subsegmental pulmonary embolism because the inter-observer agreement for angiographically documented subsegmental pulmonary embolism is only 60%. A normal rapid ELISA VIDAS D-dimer test result and a normal perfusion scan exclude pulmonary embolism with a negative predictive value of >99%, irrespective of clinical score. The positive predictive value for pulmonary embolism of a high probability VP-scan compared to pulmonary angiography is 87% indicating that 13% of patients with a high probability VP-scan do not have pulmonary embolism. ⋯ The negative predictive value during 3 months followup after a negative spiral CT for pulmonary embolism in 4 retrospective studies and 1 prospective management study was >99%. Only a small group of patients (1-2%) with a non-diagnostic spiral CT are candidates for pulmonary angiography. Therefore, it is predicted that the spiral CT will replace both VP-scanning and pulmonary angiography to safely exclude or diagnose pulmonary emboli in patients with suspected pulmonary embolism.
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Upper extremity deep vein thrombosis (UEDVT) should no longer be regarded as an uncommon and benign disease, as previously reported. It is usually associated with risk factors, as central venous lines, malignancy, and coagulation defects; however, up to 20% of UEDVTs are apparently spontaneous. The clinical picture is characterized by swelling, pain, and functional impairment, albeit UEDVT may be completely asymptomatic. ⋯ Up to 36% of the patients develop pulmonary embolism, which may be fatal; postthrombotic sequelae and recurrent thromboembolism are also frequent complications. Unfractionated or low-molecular-weight heparin followed by oral anticoagulation should be regarded as the treatment of choice; thrombolysis and surgery may be indicated in selected cases. Prophylaxis with low-dose heparin or low-dose warfarin is necessary whenever central venous catheters are positioned.