Venous Thromboembolism: Obstruction of a vein or VEINS (embolism) by a blood clot (THROMBUS) in the blood stream.Thromboembolism: Obstruction of a blood vessel (embolism) by a blood clot (THROMBUS) in the blood stream.Venous Thrombosis: The formation or presence of a blood clot (THROMBUS) within a vein.Pulmonary Embolism: Blocking of the PULMONARY ARTERY or one of its branches by an EMBOLUS.Anticoagulants: Agents that prevent clotting.Heparin, Low-Molecular-Weight: Heparin fractions with a molecular weight usually between 4000 and 6000 kD. These low-molecular-weight fractions are effective antithrombotic agents. Their administration reduces the risk of hemorrhage, they have a longer half-life, and their platelet interactions are reduced in comparison to unfractionated heparin. They also provide an effective prophylaxis against postoperative major pulmonary embolism.Thrombophilia: A disorder of HEMOSTASIS in which there is a tendency for the occurrence of THROMBOSIS.Thrombophlebitis: Inflammation of a vein associated with a blood clot (THROMBUS).Fibrin Fibrinogen Degradation Products: Soluble protein fragments formed by the proteolytic action of plasmin on fibrin or fibrinogen. FDP and their complexes profoundly impair the hemostatic process and are a major cause of hemorrhage in intravascular coagulation and fibrinolysis.Enoxaparin: Low-molecular-weight fragment of heparin, having a 4-enopyranosuronate sodium structure at the non-reducing end of the chain. It is prepared by depolymerization of the benzylic ester of porcine mucosal heparin. Therapeutically, it is used as an antithrombotic agent. (From Merck Index, 11th ed)Hemorrhage: Bleeding or escape of blood from a vessel.Stockings, Compression: Tight coverings for the foot and leg that are worn to aid circulation in the legs, and prevent the formation of EDEMA and DEEP VEIN THROMBOSIS. PNEUMATIC COMPRESSION STOCKINGS serve a similar purpose especially for bedridden patients, and following surgery.Warfarin: An anticoagulant that acts by inhibiting the synthesis of vitamin K-dependent coagulation factors. Warfarin is indicated for the prophylaxis and/or treatment of venous thrombosis and its extension, pulmonary embolism, and atrial fibrillation with embolization. It is also used as an adjunct in the prophylaxis of systemic embolism after myocardial infarction. Warfarin is also used as a rodenticide.Factor V: Heat- and storage-labile plasma glycoprotein which accelerates the conversion of prothrombin to thrombin in blood coagulation. Factor V accomplishes this by forming a complex with factor Xa, phospholipid, and calcium (prothrombinase complex). Deficiency of factor V leads to Owren's disease.Risk Factors: An aspect of personal behavior or lifestyle, environmental exposure, or inborn or inherited characteristic, which, on the basis of epidemiologic evidence, is known to be associated with a health-related condition considered important to prevent.Intermittent Pneumatic Compression Devices: Instruments that generate intermittent forces, uniformed or graduated, to facilitate the emptying of VEINS. These devices are used to reduce limb EDEMA and prevent venous THROMBOEMBOLISM, such as deep vein thrombosis in the legs.Vena Cava Filters: Mechanical devices inserted in the inferior vena cava that prevent the migration of blood clots from deep venous thrombosis of the leg.Contraceptives, Oral, Combined: Fixed drug combinations administered orally for contraceptive purposes.Recurrence: The return of a sign, symptom, or disease after a remission.Prothrombin: A plasma protein that is the inactive precursor of thrombin. It is converted to thrombin by a prothrombin activator complex consisting of factor Xa, factor V, phospholipid, and calcium ions. Deficiency of prothrombin leads to hypoprothrombinemia.Vitamin K: A lipid cofactor that is required for normal blood clotting. Several forms of vitamin K have been identified: VITAMIN K 1 (phytomenadione) derived from plants, VITAMIN K 2 (menaquinone) from bacteria, and synthetic naphthoquinone provitamins, VITAMIN K 3 (menadione). Vitamin K 3 provitamins, after being alkylated in vivo, exhibit the antifibrinolytic activity of vitamin K. Green leafy vegetables, liver, cheese, butter, and egg yolk are good sources of vitamin K.Heparin: A highly acidic mucopolysaccharide formed of equal parts of sulfated D-glucosamine and D-glucuronic acid with sulfaminic bridges. The molecular weight ranges from six to twenty thousand. Heparin occurs in and is obtained from liver, lung, mast cells, etc., of vertebrates. Its function is unknown, but it is used to prevent blood clotting in vivo and vitro, in the form of many different salts.Activated Protein C Resistance: A hemostatic disorder characterized by a poor anticoagulant response to activated protein C (APC). The activated form of Factor V (Factor Va) is more slowly degraded by activated protein C. Factor V Leiden mutation (R506Q) is the most common cause of APC resistance.Incidence: The number of new cases of a given disease during a given period in a specified population. It also is used for the rate at which new events occur in a defined population. It is differentiated from PREVALENCE, which refers to all cases, new or old, in the population at a given time.Dalteparin: A low-molecular-weight fragment of heparin, prepared by nitrous acid depolymerization of porcine mucosal heparin. The mean molecular weight is 4000-6000 daltons. It is used therapeutically as an antithrombotic agent. (From Merck Index, 11th ed)International Normalized Ratio: System established by the World Health Organization and the International Committee on Thrombosis and Hemostasis for monitoring and reporting blood coagulation tests. Under this system, results are standardized using the International Sensitivity Index for the particular test reagent/instrument combination used.Fibrinolytic Agents: Fibrinolysin or agents that convert plasminogen to FIBRINOLYSIN.Desogestrel: A synthetic progestational hormone used often as the progestogenic component of combined oral contraceptive agents.Postoperative Complications: Pathologic processes that affect patients after a surgical procedure. They may or may not be related to the disease for which the surgery was done, and they may or may not be direct results of the surgery.Postthrombotic Syndrome: A condition caused by one or more episodes of DEEP VEIN THROMBOSIS, usually the blood clots are lodged in the legs. Clinical features include EDEMA; PAIN; aching; heaviness; and MUSCLE CRAMP in the leg. When severe leg swelling leads to skin breakdown, it is called venous STASIS ULCER.Androstenes: Unsaturated derivatives of the steroid androstane containing at least one double bond at any site in any of the rings.Pregnancy Complications, Hematologic: The co-occurrence of pregnancy and a blood disease (HEMATOLOGIC DISEASES) which involves BLOOD CELLS or COAGULATION FACTORS. The hematologic disease may precede or follow FERTILIZATION and it may or may not have a deleterious effect on the pregnant woman or FETUS.Risk Assessment: The qualitative or quantitative estimation of the likelihood of adverse effects that may result from exposure to specified health hazards or from the absence of beneficial influences. (Last, Dictionary of Epidemiology, 1988)Protein C Deficiency: An absence or deficiency in PROTEIN C which leads to impaired regulation of blood coagulation. It is associated with an increased risk of severe or premature thrombosis. (Stedman's Med. Dict., 26th ed.)Protein S Deficiency: An autosomal dominant disorder showing decreased levels of plasma protein S antigen or activity, associated with venous thrombosis and pulmonary embolism. PROTEIN S is a vitamin K-dependent plasma protein that inhibits blood clotting by serving as a cofactor for activated PROTEIN C (also a vitamin K-dependent protein), and the clinical manifestations of its deficiency are virtually identical to those of protein C deficiency. Treatment with heparin for acute thrombotic processes is usually followed by maintenance administration of coumarin drugs for the prevention of recurrent thrombosis. (From Harrison's Principles of Internal Medicine, 12th ed, p1511; Wintrobe's Clinical Hematology, 9th ed, p1523)Phlebography: Radiographic visualization or recording of a vein after the injection of contrast medium.Bandages: Material used for wrapping or binding any part of the body.Levonorgestrel: A synthetic progestational hormone with actions similar to those of PROGESTERONE and about twice as potent as its racemic or (+-)-isomer (NORGESTREL). It is used for contraception, control of menstrual disorders, and treatment of endometriosis.ThiophenesProspective Studies: Observation of a population for a sufficient number of persons over a sufficient number of years to generate incidence or mortality rates subsequent to the selection of the study group.Thrombosis: Formation and development of a thrombus or blood clot in the blood vessel.beta-Alanine: An amino acid formed in vivo by the degradation of dihydrouracil and carnosine. Since neuronal uptake and neuronal receptor sensitivity to beta-alanine have been demonstrated, the compound may be a false transmitter replacing GAMMA-AMINOBUTYRIC ACID. A rare genetic disorder, hyper-beta-alaninemia, has been reported.AustriaFactor Xa: Activated form of factor X that participates in both the intrinsic and extrinsic pathways of blood coagulation. It catalyzes the conversion of prothrombin to thrombin in conjunction with other cofactors.Norpregnenes: Pregnenes with one double bond or more than three double bonds which have undergone ring contractions or are lacking carbon-18 or carbon-19..Neoplasms: New abnormal growth of tissue. Malignant neoplasms show a greater degree of anaplasia and have the properties of invasion and metastasis, compared to benign neoplasms.Retrospective Studies: Studies used to test etiologic hypotheses in which inferences about an exposure to putative causal factors are derived from data relating to characteristics of persons under study or to events or experiences in their past. The essential feature is that some of the persons under study have the disease or outcome of interest and their characteristics are compared with those of unaffected persons.Contraceptives, Oral, Synthetic: Oral contraceptives which owe their effectiveness to synthetic preparations.Practice Guidelines as Topic: Directions or principles presenting current or future rules of policy for assisting health care practitioners in patient care decisions regarding diagnosis, therapy, or related clinical circumstances. The guidelines may be developed by government agencies at any level, institutions, professional societies, governing boards, or by the convening of expert panels. The guidelines form a basis for the evaluation of all aspects of health care and delivery.Acenocoumarol: A coumarin that is used as an anticoagulant. Its actions and uses are similar to those of WARFARIN. (From Martindale, The Extra Pharmacopoeia, 30th ed, p233)Risk: The probability that an event will occur. It encompasses a variety of measures of the probability of a generally unfavorable outcome.Pregnancy Complications, Cardiovascular: The co-occurrence of pregnancy and a cardiovascular disease. The disease may precede or follow FERTILIZATION and it may or may not have a deleterious effect on the pregnant woman or FETUS.Treatment Outcome: Evaluation undertaken to assess the results or consequences of management and procedures used in combating disease in order to determine the efficacy, effectiveness, safety, and practicability of these interventions in individual cases or series.Contraceptives, Oral: Compounds, usually hormonal, taken orally in order to block ovulation and prevent the occurrence of pregnancy. The hormones are generally estrogen or progesterone or both.Cohort Studies: Studies in which subsets of a defined population are identified. These groups may or may not be exposed to factors hypothesized to influence the probability of the occurrence of a particular disease or other outcome. Cohorts are defined populations which, as a whole, are followed in an attempt to determine distinguishing subgroup characteristics.Compression Bandages: Strips of elastic material used to apply pressure to body parts to control EDEMA and aid circulation.Blood Coagulation: The process of the interaction of BLOOD COAGULATION FACTORS that results in an insoluble FIBRIN clot.Pyridones: Pyridine derivatives with one or more keto groups on the ring.Arthroplasty, Replacement, Knee: Replacement of the knee joint.Administration, Oral: The giving of drugs, chemicals, or other substances by mouth.Injections, Subcutaneous: Forceful administration under the skin of liquid medication, nutrient, or other fluid through a hollow needle piercing the skin.Follow-Up Studies: Studies in which individuals or populations are followed to assess the outcome of exposures, procedures, or effects of a characteristic, e.g., occurrence of disease.Immobilization: The restriction of the MOVEMENT of whole or part of the body by physical means (RESTRAINT, PHYSICAL) or chemically by ANALGESIA, or the use of TRANQUILIZING AGENTS or NEUROMUSCULAR NONDEPOLARIZING AGENTS. It includes experimental protocols used to evaluate the physiologic effects of immobility.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Hospitalization: The confinement of a patient in a hospital.Case-Control Studies: Studies which start with the identification of persons with a disease of interest and a control (comparison, referent) group without the disease. The relationship of an attribute to the disease is examined by comparing diseased and non-diseased persons with regard to the frequency or levels of the attribute in each group.Protein C: A vitamin-K dependent zymogen present in the blood, which, upon activation by thrombin and thrombomodulin exerts anticoagulant properties by inactivating factors Va and VIIIa at the rate-limiting steps of thrombin formation.Antithrombins: Endogenous factors and drugs that directly inhibit the action of THROMBIN, usually by blocking its enzymatic activity. They are distinguished from INDIRECT THROMBIN INHIBITORS, such as HEPARIN, which act by enhancing the inhibitory effects of antithrombins.Arthroplasty, Replacement, Hip: Replacement of the hip joint.Aerospace Medicine: That branch of medicine dealing with the studies and effects of flight through the atmosphere or in space upon the human body and with the prevention or cure of physiological or psychological malfunctions arising from these effects. (from NASA Thesaurus)Gravity Suits: Double-layered inflatable suits which, when inflated, exert pressure on the lower part of the wearer's body. The suits are used to improve or stabilize the circulatory state, i.e., to prevent hypotension, control hemorrhage, and regulate blood pressure. The suits are also used by pilots under positive acceleration.Hospital Bed Capacity, 300 to 499Double-Blind Method: A method of studying a drug or procedure in which both the subjects and investigators are kept unaware of who is actually getting which specific treatment.Blood Coagulation Factors: Endogenous substances, usually proteins, that are involved in the blood coagulation process.Orthopedic Procedures: Procedures used to treat and correct deformities, diseases, and injuries to the MUSCULOSKELETAL SYSTEM, its articulations, and associated structures.Factor VIII: Blood-coagulation factor VIII. Antihemophilic factor that is part of the factor VIII/von Willebrand factor complex. Factor VIII is produced in the liver and acts in the intrinsic pathway of blood coagulation. It serves as a cofactor in factor X activation and this action is markedly enhanced by small amounts of thrombin.Guideline Adherence: Conformity in fulfilling or following official, recognized, or institutional requirements, guidelines, recommendations, protocols, pathways, or other standards.Antithrombin III Deficiency: An absence or reduced level of Antithrombin III leading to an increased risk for thrombosis.Partial Thromboplastin Time: The time required for the appearance of FIBRIN strands following the mixing of PLASMA with phospholipid platelet substitute (e.g., crude cephalins, soybean phosphatides). It is a test of the intrinsic pathway (factors VIII, IX, XI, and XII) and the common pathway (fibrinogen, prothrombin, factors V and X) of BLOOD COAGULATION. It is used as a screening test and to monitor HEPARIN therapy.Randomized Controlled Trials as Topic: Works about clinical trials that involve at least one test treatment and one control treatment, concurrent enrollment and follow-up of the test- and control-treated groups, and in which the treatments to be administered are selected by a random process, such as the use of a random-numbers table.PolysaccharidesDrug Administration Schedule: Time schedule for administration of a drug in order to achieve optimum effectiveness and convenience.Premedication: Preliminary administration of a drug preceding a diagnostic, therapeutic, or surgical procedure. The commonest types of premedication are antibiotics (ANTIBIOTIC PROPHYLAXIS) and anti-anxiety agents. It does not include PREANESTHETIC MEDICATION.MorpholinesInpatients: Persons admitted to health facilities which provide board and room, for the purpose of observation, care, diagnosis or treatment.Factor V Deficiency: A deficiency of blood coagulation factor V (known as proaccelerin or accelerator globulin or labile factor) leading to a rare hemorrhagic tendency known as Owren's disease or parahemophilia. It varies greatly in severity. Factor V deficiency is an autosomal recessive trait. (Dorland, 27th ed)Puerperal Disorders: Disorders or diseases associated with PUERPERIUM, the six-to-eight-week period immediately after PARTURITION in humans.Blood Coagulation Tests: Laboratory tests for evaluating the individual's clotting mechanism.Antiphospholipid Syndrome: The presence of antibodies directed against phospholipids (ANTIBODIES, ANTIPHOSPHOLIPID). The condition is associated with a variety of diseases, notably systemic lupus erythematosus and other connective tissue diseases, thrombopenia, and arterial or venous thromboses. In pregnancy it can cause abortion. Of the phospholipids, the cardiolipins show markedly elevated levels of anticardiolipin antibodies (ANTIBODIES, ANTICARDIOLIPIN). Present also are high levels of lupus anticoagulant (LUPUS COAGULATION INHIBITOR).Antibodies, Antiphospholipid: Autoantibodies directed against phospholipids. These antibodies are characteristically found in patients with systemic lupus erythematosus (LUPUS ERYTHEMATOSUS, SYSTEMIC;), ANTIPHOSPHOLIPID SYNDROME; related autoimmune diseases, some non-autoimmune diseases, and also in healthy individuals.Age Factors: Age as a constituent element or influence contributing to the production of a result. It may be applicable to the cause or the effect of a circumstance. It is used with human or animal concepts but should be differentiated from AGING, a physiological process, and TIME FACTORS which refers only to the passage of time.Benzimidazoles: Compounds with a BENZENE fused to IMIDAZOLES.Aspirin: The prototypical analgesic used in the treatment of mild to moderate pain. It has anti-inflammatory and antipyretic properties and acts as an inhibitor of cyclooxygenase which results in the inhibition of the biosynthesis of prostaglandins. Aspirin also inhibits platelet aggregation and is used in the prevention of arterial and venous thrombosis. (From Martindale, The Extra Pharmacopoeia, 30th ed, p5)Contraceptives, Oral, Hormonal: Oral contraceptives which owe their effectiveness to hormonal preparations.Estrogen Replacement Therapy: The use of hormonal agents with estrogen-like activity in postmenopausal or other estrogen-deficient women to alleviate effects of hormone deficiency, such as vasomotor symptoms, DYSPAREUNIA, and progressive development of OSTEOPOROSIS. This may also include the use of progestational agents in combination therapy.Femoral Vein: The vein accompanying the femoral artery in the same sheath; it is a continuation of the popliteal vein and becomes the external iliac vein.Early Ambulation: Procedure to accelerate the ability of a patient to walk or move about by reducing the time to AMBULATION. It is characterized by a shorter period of hospitalization or recumbency than is normally practiced.Intrauterine Devices, Medicated: Intrauterine devices that release contraceptive agents.Benzylamines: Toluenes in which one hydrogen of the methyl group is substituted by an amino group. Permitted are any substituents on the benzene ring or the amino group.Postphlebitic Syndrome: A condition characterized by a chronically swollen limb, often a leg with stasis dermatitis and ulcerations. This syndrome can appear soon after phlebitis or years later. Postphlebitic syndrome is the result of damaged or incompetent venous valves in the limbs. Distended, tortuous VARICOSE VEINS are usually present. Leg pain may occur after long period of standing.Acute Disease: Disease having a short and relatively severe course.AzetidinesBlood Coagulation Disorders: Hemorrhagic and thrombotic disorders that occur as a consequence of abnormalities in blood coagulation due to a variety of factors such as COAGULATION PROTEIN DISORDERS; BLOOD PLATELET DISORDERS; BLOOD PROTEIN DISORDERS or nutritional conditions.Nadroparin: A heparin fraction with a mean molecular weight of 4500 daltons. It is isolated from porcine mucosal heparin and used as an antithrombotic agent. (From Merck Index, 11th ed)Antithrombin III: A plasma alpha 2 glycoprotein that accounts for the major antithrombin activity of normal plasma and also inhibits several other enzymes. It is a member of the serpin superfamily.Registries: The systems and processes involved in the establishment, support, management, and operation of registers, e.g., disease registers.Protein S: The vitamin K-dependent cofactor of activated PROTEIN C. Together with protein C, it inhibits the action of factors VIIIa and Va. A deficiency in protein S; (PROTEIN S DEFICIENCY); can lead to recurrent venous and arterial thrombosis.Chemoprevention: The use of chemical compounds to prevent the development of a specific disease.United StatesMassachusettsAircraft: A weight-carrying structure for navigation of the air that is supported either by its own buoyancy or by the dynamic action of the air against its surfaces. (Webster, 1973)Stroke: A group of pathological conditions characterized by sudden, non-convulsive loss of neurological function due to BRAIN ISCHEMIA or INTRACRANIAL HEMORRHAGES. Stroke is classified by the type of tissue NECROSIS, such as the anatomic location, vasculature involved, etiology, age of the affected individual, and hemorrhagic vs. non-hemorrhagic nature. (From Adams et al., Principles of Neurology, 6th ed, pp777-810)Tertiary Prevention: Measures aimed at providing appropriate supportive and rehabilitative services to minimize morbidity and maximize quality of life after a long-term disease or injury is present.Comorbidity: The presence of co-existing or additional diseases with reference to an initial diagnosis or with reference to the index condition that is the subject of study. Comorbidity may affect the ability of affected individuals to function and also their survival; it may be used as a prognostic indicator for length of hospital stay, cost factors, and outcome or survival.Anesthesia, Conduction: Injection of an anesthetic into the nerves to inhibit nerve transmission in a specific part of the body.Proportional Hazards Models: Statistical models used in survival analysis that assert that the effect of the study factors on the hazard rate in the study population is multiplicative and does not change over time.Odds Ratio: The ratio of two odds. The exposure-odds ratio for case control data is the ratio of the odds in favor of exposure among cases to the odds in favor of exposure among noncases. The disease-odds ratio for a cohort or cross section is the ratio of the odds in favor of disease among the exposed to the odds in favor of disease among the unexposed. The prevalence-odds ratio refers to an odds ratio derived cross-sectionally from studies of prevalent cases.Fibrin Clot Lysis Time: A measurement of the time needed for FIBRINOLYSIS to occur.Embolectomy: Surgical removal of an obstructing clot or foreign material which has been transported from a distant vessel by the bloodstream. Removal of a clot at its original site is called THROMBECTOMY.Catheterization, Central Venous: Placement of an intravenous CATHETER in the subclavian, jugular, or other central vein.Progestins: Compounds that interact with PROGESTERONE RECEPTORS in target tissues to bring about the effects similar to those of PROGESTERONE. Primary actions of progestins, including natural and synthetic steroids, are on the UTERUS and the MAMMARY GLAND in preparation for and in maintenance of PREGNANCY.Intracranial Hemorrhage, Traumatic: Bleeding within the SKULL induced by penetrating and nonpenetrating traumatic injuries, including hemorrhages into the tissues of CEREBRUM; BRAIN STEM; and CEREBELLUM; as well as into the epidural, subdural and subarachnoid spaces of the MENINGES.Surgical Procedures, Operative: Operations carried out for the correction of deformities and defects, repair of injuries, and diagnosis and cure of certain diseases. (Taber, 18th ed.)Primary Prevention: Specific practices for the prevention of disease or mental disorders in susceptible individuals or populations. These include HEALTH PROMOTION, including mental health; protective procedures, such as COMMUNICABLE DISEASE CONTROL; and monitoring and regulation of ENVIRONMENTAL POLLUTANTS. Primary prevention is to be distinguished from SECONDARY PREVENTION and TERTIARY PREVENTION.Predictive Value of Tests: In screening and diagnostic tests, the probability that a person with a positive test is a true positive (i.e., has the disease), is referred to as the predictive value of a positive test; whereas, the predictive value of a negative test is the probability that the person with a negative test does not have the disease. Predictive value is related to the sensitivity and specificity of the test.Prevalence: The total number of cases of a given disease in a specified population at a designated time. It is differentiated from INCIDENCE, which refers to the number of new cases in the population at a given time.Logistic Models: Statistical models which describe the relationship between a qualitative dependent variable (that is, one which can take only certain discrete values, such as the presence or absence of a disease) and an independent variable. A common application is in epidemiology for estimating an individual's risk (probability of a disease) as a function of a given risk factor.Thrombolytic Therapy: Use of infusions of FIBRINOLYTIC AGENTS to destroy or dissolve thrombi in blood vessels or bypass grafts.Atrial Fibrillation: Abnormal cardiac rhythm that is characterized by rapid, uncoordinated firing of electrical impulses in the upper chambers of the heart (HEART ATRIA). In such case, blood cannot be effectively pumped into the lower chambers of the heart (HEART VENTRICLES). It is caused by abnormal impulse generation.Thrombin: An enzyme formed from PROTHROMBIN that converts FIBRINOGEN to FIBRIN.Hip Fractures: Fractures of the FEMUR HEAD; the FEMUR NECK; (FEMORAL NECK FRACTURES); the trochanters; or the inter- or subtrochanteric region. Excludes fractures of the acetabulum and fractures of the femoral shaft below the subtrochanteric region (FEMORAL FRACTURES).Kaplan-Meier Estimate: A nonparametric method of compiling LIFE TABLES or survival tables. It combines calculated probabilities of survival and estimates to allow for observations occurring beyond a measurement threshold, which are assumed to occur randomly. Time intervals are defined as ending each time an event occurs and are therefore unequal. (From Last, A Dictionary of Epidemiology, 1995)Surgical Procedures, Elective: Surgery which could be postponed or not done at all without danger to the patient. Elective surgery includes procedures to correct non-life-threatening medical problems as well as to alleviate conditions causing psychological stress or other potential risk to patients, e.g., cosmetic or contraceptive surgery.Plethysmography, Impedance: Recording changes in electrical impedance between electrodes placed on opposite sides of a part of the body, as a measure of volume changes in the path of the current. (Stedman, 25th ed)Cell-Derived Microparticles: Extracellular vesicles generated by the shedding of CELL MEMBRANE blebs.DenmarkIntention to Treat Analysis: Strategy for the analysis of RANDOMIZED CONTROLLED TRIALS AS TOPIC that compares patients in the groups to which they were originally randomly assigned.Thrombectomy: Surgical removal of an obstructing clot or foreign material from a blood vessel at the point of its formation. Removal of a clot arising from a distant site is called EMBOLECTOMY.
Superficial vein thrombosis: Superficial vein thrombosis (SVT) is a type of venous thrombosis, or a blood clot in a vein, which forms in a superficial vein near the surface of the body. Usually there is an inflammatory reaction around the vein which presents as a painful induration with erythema.Pulmonary angiography: Pulmonary angiography (or pulmonary arteriography) is a cardiological medical procedure. Pulmonary blood vessels are x-rayed to detect arteriovenous malformations.Anticoagulant: Anticoagulants are a class of drugs that work to prevent the coagulation (clotting) of blood. Such substances occur naturally in leeches and blood-sucking insects.Low molecular weight heparin: In medicine, low-molecular-weight heparin (LMWH) is a class of anticoagulant medications. They are used in the prevention and treatment of venous thromboembolism (deep vein thrombosis and pulmonary embolism) and in the treatment of myocardial infarction.ThrombophiliaPhlegmasia cerulea dolens: Phlegmasia cerulea dolens (literally: painful blue edema) is an uncommon severe form of deep venous thrombosis which results from extensive thrombotic occlusion (blockage by a thrombus) of the major and the collateral veins of an extremity. It is characterized by sudden severe pain, swelling, cyanosis and edema of the affected limb.D-dimer: D-dimer (or D dimer) is a fibrin degradation product (or FDP), a small protein fragment present in the blood after a blood clot is degraded by fibrinolysis. It is so named because it contains two crosslinked D fragments of the fibrin protein.Pulmonary hemorrhageWarfarinWeigh House (Leiden)QRISK: QRISK2 (the most recent version of QRISK) is a prediction algorithm for cardiovascular disease (CVD) that uses traditional risk factors (age, systolic blood pressure, smoking status and ratio of total serum cholesterol to high-density lipoprotein cholesterol) together with body mass index, ethnicity, measures of deprivation, family history, chronic kidney disease, rheumatoid arthritis, atrial fibrillation, diabetes mellitus, and antihypertensive treatment.Inferior vena cava filter: An inferior vena cava filter (IVC filter) is a type of vascular filter, a medical device that is implanted by interventional radiologists or vascular surgeons into the inferior vena cava to presumably prevent life-threatening pulmonary emboli (PEs). Their effectiveness and safety profile is not well established, and in general, they are only recommended in some high-risk scenarios.Prothrombin G20210A: Prothrombin G20210A (also the prothrombin 20210 mutation, the factor II mutation, or the prothrombin mutation) is a genetic variant that approximately doubles or triples the risk of forming blood clots in the veins. The variant is commonly associated with the disease venous thromboembolism (VTE), which includes both deep vein thrombosis and pulmonary embolism.Vitamin K reactionIncidence (epidemiology): Incidence is a measure of the probability of occurrence of a given medical condition in a population within a specified period of time. Although sometimes loosely expressed simply as the number of new cases during some time period, it is better expressed as a proportion or a rate with a denominator.Antithrombotic: An antithrombotic agent is a drug that reduces the formation of blood clots (thrombi).http://cancerweb.DesogestrelDrospirenoneGestational thrombocytopeniaGlobal Risks Report: The Global Risks Report is an annual study published by the World Economic Forum ahead of the Forum’s Annual Meeting in Davos, Switzerland. Based on the work of the Global Risk Network, the report describes changes occurring in the global risks landscape from year to year and identifies the global risks that could play a critical role in the upcoming year.Impedance phlebographyElastic bandage: An elastic bandage is a "stretchable bandage used to create localized pressure". Elastic bandages are commonly used to treat muscle sprains and strains by reducing the flow of blood to a particular area by the application of even stable pressure which can restrict swelling at the place of injury.LevonorgestrelBenzo(c)thiopheneThrombusHealthcare in Austria: The nation of Austria has a two-tier health care system in which virtually all individuals receive publicly funded care, but they also have the option to purchase supplementary private health insurance. Some individuals choose to completely pay for their care privately.DarexabanGestodeneNational Clinical Guideline CentreOral contraceptive pill: Oral contraceptives, abbreviated OCPs, also known as birth control pills, are medications taken by mouth for the purpose of birth control.Ford Essex V4 engineCoagulation testing: Blood clotting tests are the tests used for diagnostics of the hemostasis system.Mineral salts pyridone broth: Mineral salts pyridone broth is a selective medium for bacteria that can metabolize pyridone (which is an unusual carbon source that a select few types of bacteria can use). This medium is used to isolate bacteria belonging to the Arthrobacter genus among other bacteria genera.Oxford knee score: The Oxford Knee Score (OKS) is a Patient Reported Outcome questionnaire that was developed to specifically assess the patient's perspective of outcome following Total Knee Arthroplasty. The OKS has subsequently been validated for use in assessing other non-surgical therapies applied to those suffering from issues with the knee.Osmotic controlled-release oral delivery system: OROS (Osmotic [Controlled] Release Oral [Delivery] System) is a controlled release oral drug delivery system in the form of a tablet. The tablet has a rigid water-permeable jacket with one or more laser drilled small holes.Subcutaneous injectionTemporal analysis of products: Temporal Analysis of Products (TAP), (TAP-2), (TAP-3) is an experimental technique for studyingNested case-control study: A nested case control (NCC) study is a variation of a case-control study in which only a subset of controls from the cohort are compared to the incident cases. In a case-cohort study, all incident cases in the cohort are compared to a random subset of participants who do not develop the disease of interest.Drotrecogin alfaInogatranMinimally invasive hip resurfacing: Minimally invasive hip resurfacing (MIS) is "total or partial hip surgery that can be carried out through an incision of less than 10 cm (3.94 inches) without imparting great forces on the anatomy or compromising component positioning"Comis Orthopaedics websiteList of Royal Air Force aircraft independent flights: This is a list of Royal Air Force independent Flights. An independent Flight is a military administrative structure which is used to command flying units where the number of aircraft is not large enough to warrant a fully fledged squadron.Non-pneumatic anti-shock garment: The non-pneumatic anti-shock garment (NASG) is a low-technology first-aid device used to treat hypovolemic shock. Its efficacy for reducing maternal deaths due to obstetrical hemorrhage is being researched.Placebo-controlled study: Placebo-controlled studies are a way of testing a medical therapy in which, in addition to a group of subjects that receives the treatment to be evaluated, a separate control group receives a sham "placebo" treatment which is specifically designed to have no real effect. Placebos are most commonly used in blinded trials, where subjects do not know whether they are receiving real or placebo treatment.Aafact: Aafact is a monoclonal purified factor VIII concentrate. It consists of a protein fraction prepared from fresh-frozen human plasma.Antithrombin III deficiencyPartial thromboplastin time: The partial thromboplastin time (PTT) or activated partial thromboplastin time (aPTT or APTT) is a medical test that characterizes blood coagulation.AIP Conference Proceedings: AIP Conference Proceedings is a serial published by the American Institute of Physics since 1970. It publishes the proceedings from various conferences of physics societies.Premedication: Premedication refer to a drug treatment given to a patient before a (surgical or invasive) medical procedure. These drugs are typically sedative or analgesic.MorpholinePuerperal disorderAntiphospholipid syndrome: (ILDS D68.810)Age adjustment: In epidemiology and demography, age adjustment, also called age standardization, is a technique used to allow populations to be compared when the age profiles of the populations are quite different.ClemizoleAspirinEstrogenFemoral vein: In the human body, the femoral vein is a blood vessel that accompanies the femoral artery in the femoral sheath. It begins at the adductor canal (also known as Hunter's canal) and is a continuation of the popliteal vein.EzlopitantPost-thrombotic syndrome: Post-thrombotic syndrome (PTS), also called postphlebitic syndrome and venous stress disorder is a medical condition that may occur as a long-term complication of deep vein thrombosis (DVT).
(1/679) Acquired risk factors for venous thromboembolism in medical patients.
Acute venous thromboembolism (VTE) is a serious and potentially fatal disorder, which often complicates the course of hospitalized patients, but may also affect ambulatory and otherwise healthy people. While the introduction of thromboprophylactic measures is expected to have reduced the occurrence of postoperative VTE, there is an increasing awareness of the importance of medical conditions in determining thromboembolic events. Among the conditions that predispose patients to VTE are increasing age, cancer and its treatment, prolonged immobility, stroke or paralysis, previous VTE, congestive heart failure, acute infection, pregnancy or puerperium, dehydration, hormonal treatment, varicose veins, long air travel, acute inflammatory bowel disease, rheumatologic disease, and nephrotic syndrome. Other factors that have recently been associated with an increased risk of VTE disorders include persistent elevation of D-dimer and atherosclerotic disease. Recognition of the incidence and clinical importance of thrombosis will most likely encourage more widespread use of antithrombotic prophylaxis in medical patients. (+info)
(2/679) Thrombosis and the antiphospholipid syndrome.
The antiphospholipid syndrome is an antibody-mediated hypercoagulable state characterized by recurrent venous and arterial thromboembolic events. Several studies have determined that the frequency of antiphospholipid syndrome in patients presenting with a venous thromboembolic event is between 4% and 14%. Because of the high risk for recurrent thromboembolism in these patients, current recommendations suggest a longer, potentially lifelong, course of antithrombotic therapy following an initial event. Although most authorities agree on an extended course of therapy, considerable controversy surrounds the optimal target therapeutic INR for patients with antiphospholipid syndrome. For an initial venous thromboembolic event, a target INR of 2.0 to 3.0 is supported by two prospective, randomized clinical trials. In contrast, relatively limited data exist for an initial arterial thromboembolic event in patients who have the antiphospholipid syndrome, and therapeutic recommendations range from aspirin to warfarin with a high target INR. Recurrent thromboembolic events can be extremely difficult to treat, and some patients may benefit from the addition of immunosuppressive therapies. Importantly, as many as 50% of the initial thromboembolic events sustained by patients with antiphospholipid antibodies occur in the setting of additional, coincident prothrombotic risk factors, indicating the importance of addressing any additional risk factors, such as hypercholesterolemia, in these patients. Prospective studies are needed to address the role of thromboprophylactic strategies in asymptomatic individuals with antiphospholipid antibodies in the absence of additional risk factors. (+info)
(3/679) Prophylaxis of venous thrombosis in medical patients: A real-world perspective.
BACKGROUND: Although low-molecular weight heparins (LMWH) have been proven to be efficacious for prophylaxis of venous thrombo-embolism (VTE) in non-surgical patients, their use and safety outside the setting of a clinical trial has not been investigated. OBJECTIVE: The objective of this survey was to determine the efficacy and safety of LMWH (enoxaparin) in the prevention of VTE in a study population comprising general medical patients. METHODS: The study involved an open-label, non-controlled, multicentre survey of any patient confined to bed due to medical illness, where the physician had made an independent decision to prescribe LMWH as prophylaxis for VTE. The demographic information and risk factors for venous thrombosis and dose of enoxaparin were recorded. Patients were assessed for clinical evidence of VTE. Only if this was present were further invasive investigations performed. Adverse events relating to the use of LMWH were recorded. RESULTS: Four hundred and seventy-one patients were enrolled from 53 centres. Five per cent of the patients were treated for up to and including three days, 4.4% for four days or less, 49.6% for six days or less, and a further 45.5 % for seven to 21 days. The most frequently prescribed dose was enoxaparin 40 mg once daily (86%). Of the enrolled patients, 28.2% had one risk factor and 69.8% had two or more risk factors for the development of VTE. The incidence of clinically suspected deep-vein thrombosis (DVT) or pulmonary embolism (PE) in this survey was three out of 457 patients at risk, ie, 0.66%. One serious adverse event occurred in an incorrectly enrolled surgical patient and 22 minor adverse events occurred that were thought by the enrolling physician to be related to the study drug. CONCLUSION: This survey was not designed to test for efficacy in DVT prevention. However the incidence of clinically identified DVT was low and there were no deaths from PE. This probably represents a considerable reduction in morbidity and mortality from that described in studies comparing LMWH with placebo. Enoxaparin may be used with confidence in a 'real-world' situation out of the confines of a study in which exclusions, inclusions and therapy are rigorously controlled. (+info)
(4/679) The association of alpha-fibrinogen Thr312Ala polymorphism and venous thromboembolism in the LITE study.
INTRODUCTION: The alpha-fibrinogen Thr312Ala variant has been shown to influence clot structure through increased factor XIII cross-linking and formation of thicker fibrin fibers. However, the effect of this common variant on risk of venous thromboembolism (VTE) is unclear. This paper reports the association between the Thr312Ala variant and VTE in the LITE study. MATERIALS AND METHODS: 506 cases and 1014 controls frequency matched on age, sex, race, and study were drawn from two prospective studies and included in the analysis. Logistic regression was used to examine the association between Thr312Ala and VTE. RESULTS: In a logistic regression model minimally adjusted for the matching variables, the Thr312Ala TA and AA genotypes were associated with a significantly higher risk of VTE than the TT genotype (TA OR and 95% confidence interval 1.27 [1.01-1.60], AA OR 1.49 [1.00-2.22]). Associations were similar in analyses of PE and DVT considered separately and across racial and study subgroups. The association between alpha-fibrinogen Thr312Ala and VTE was modified by both BMI and the FXIII Val34Leu variant; the combination of elevated BMI or FXIII Val34Leu with alpha-fibrinogen Thr312Ala conveyed lower odds of VTE than would be expected by an additive or multiplicative model of individual risk factors. CONCLUSIONS: These results suggest that alpha-fibrinogen Thr312Ala is involved in the pathogenesis of VTE and that its action may be modified by other VTE risk factors. (+info)
(5/679) Fondaparinux prevents venous thromboembolism after joint replacement surgery in Japanese patients.
Venous thromboembolism (VTE) is an important complication of major orthopaedic surgery of the lower limbs. Fondaparinux, a synthetic pentasaccharide and highly selective inhibitor of activated Factor Xa, is the first in a new class of antithrombotic agents. To determine the optimal dose in Japanese patients, double-blind, placebo-controlled, dose-ranging studies of fondaparinux were conducted in patients undergoing total knee replacement (TKR) or total hip replacement (THR) surgery. Patients were randomly assigned to receive a once-daily subcutaneous injection of fondaparinux (0.75, 1.5, 2.5, or 3.0 mg) or placebo in Study 1 (TKR) and Study 2 (THR). In Study 1, the incidence of VTE was 65.3% in the placebo group and was 34.2%, 21.3%, 16.2%, and 9.5% in the groups receiving 0.75, 1.5, 2.5, and 3.0 mg fondaparinux respectively. In Study 2, the incidence of VTE was 33.8% in the placebo group and was 24.2%, 4.6%, 7.4%, and 14.4% in the 0.75, 1.5, 2.5, and 3.0 mg fondaparinux groups respectively. Dose-response effects were observed in both studies; however, no statistically significant differences in major bleeding events were found among any groups. Fondaparinux proved to be a potent anticoagulant with a favourable benefit-to-risk ratio in the prevention of VTE in these study patients. (+info)
(6/679) Detection of venous thromboembolism by proteomic serum biomarkers.
BACKGROUND: Available blood assays for venous thromboembolism (VTE) suffer from diminished specificity. Compared with single marker tests, such as D-dimer, a multi-marker strategy may improve diagnostic ability. We used direct mass spectrometry (MS) analysis of serum from patients with VTE to determine whether protein expression profiles would predict diagnosis. METHODS AND RESULTS: We developed a direct MS and computational approach to the proteomic analysis of serum. Using this new method, we analyzed serum from inpatients undergoing radiographic evaluation for VTE. In a balanced cohort of 76 patients, a neural network-based prediction model was built using a training subset of the cohort to first identify proteomic patterns of VTE. The proteomic patterns were then validated in a separate group of patients within the cohort. The model yielded a sensitivity of 68% and specificity of 89%, which exceeded the specificity of D-dimer assay tested by latex agglutination, ELISA, and immunoturbimetric methods (sensitivity/specificity of 63.2%/60.5%, 97.4%/21.1%, 97.4%/15.8%, respectively). We validated differences in protein expression between patients with and without VTE using more traditional gel-based analysis of the same serum samples. CONCLUSION: Protein expression analysis of serum using direct MS demonstrates potential diagnostic utility for VTE. This pilot study is the first such direct MS study to be applied to a cardiovascular disease. Differences in protein expression were identified and subsequently validated in a separate group of patients. The findings in this initial cohort can be evaluated in other independent cohorts, including patients with inflammatory conditions and chronic (but not acute) VTE, for the diagnosis of VTE. (+info)
(7/679) The use of enoxaparin to prevent venous thromboembolism in patients undergoing radical retropubic prostatectomy: feasibility and utility.
OBJECTIVE: To assess the utility of enoxaparin in prevention of venous thromboembolism (VTE) in men poorly compliant with pneumatic compression stockings (PCS) in the immediate postoperative period after a radical retropubic prostatectomy (RP). MATERIALS AND METHODS: This retrospective study included 47 men who underwent RP at an inner-city tertiary care hospital. All patients were started on enoxaparin 40 mg subcutaneously 6-8 hours postoperatively and daily while hospitalized. Preoperative, operative, and postoperative data were collected and analyzed. Median follow-up was 18 months. RESULTS: Median patient age was 64 +/- 7 years, median prostate-specific antigen level was 4.9 ng/mL and median prostate biopsy-determined Gleason score was 6. Forty-one men (87%) underwent a pelvic lymph node dissection. Median operative time was 181 minutes (range 164-450 minutes). Median estimated blood loss was 700 mL. Approximately 36% of the men wore PCS the recommended > 19 hours/day. On average PCS were worn 10.3 +/- 7.5 hours/day. Postoperative complications were not increased in this cohort. Two patients developed pulmonary embolism requiring long-term anticoagulation. There were no mortalities. CONCLUSIONS: In men non-compliant with PCS, initiation of enoxaparin in the immediate postoperative setting was well-tolerated and maintained a low (4%) rate of VTE. Thus, enoxaparin may be useful in adjunct with PCS in these patients. (+info)
(8/679) Venous thromboembolism predicts poor prognosis in irresectable pancreatic cancer patients.
BACKGROUND: The aim was to investigate the outcomes associated with venous thromboembolism (VTE) among irresectable pancreatic cancer patients. METHODS: This is a follow-up study of consecutive irresectable cancer patients, treated and followed up in clinical trials between December 2001 and December 2004 in order to evaluate the prognostic impact of symptomatic VTE on clinical outcomes, such as response to treatment, progression-free survival (PFS) and overall survival (OS). RESULTS: Among 227 irresectable pancreatic cancer patients, with Eastern Cooperative Oncology Group performance status (ECOG-PS) < or = 2, 59 (26.0%) patients developed a VTE. A synchronous VTE occurred in 28 (12.3%) patients, while a VTE during chemotherapy was observed in 15 (6.6%) patients, and 16 (7.0%) patients experienced both events. Presence of synchronous VTE was associated with a higher probability of not responding to treatment (odds ratio 2.98, 95% CI 1.42-6.27, P = 0.004), but showed no effect on both PFS and OS at least at multivariate analysis. Occurrence of a VTE during chemotherapy showed a statistically significant effect on PFS (hazard ratio [HR] 2.59, 95% CI 1.69-3.97, P < 0.0001) and OS (HR 1.64, 95%CI 1.04-2.58, P = 0.032). CONCLUSIONS: Our data suggest that the occurrence of VTE may be associated with a reduced response rate and a shorter PFS and OS among patients with irresectable pancreatic cancer. In these patients the development of VTE may reflect the presence of a biologically more aggressive cancer that in turn leads to a worse prognosis. (+info)
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