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.Pulmonary Embolism: Blocking of the PULMONARY ARTERY or one of its branches by an EMBOLUS.Venous Thrombosis: The formation or presence of a blood clot (THROMBUS) within a vein.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).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.Hemorrhage: Bleeding or escape of blood from a vessel.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)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.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.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.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.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.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.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.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.Fibrinolytic Agents: Fibrinolysin or agents that convert plasminogen to FIBRINOLYSIN.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.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.Thrombosis: Formation and development of a thrombus or blood clot in the blood vessel.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.Contraceptives, Oral, Combined: Fixed drug combinations administered orally for contraceptive purposes.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.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)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.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.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.)Prospective 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.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.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.Bandages: Material used for wrapping or binding any part of the body.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.Phlebography: Radiographic visualization or recording of a vein after the injection of contrast medium.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.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)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.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)Desogestrel: A synthetic progestational hormone used often as the progestogenic component of combined oral contraceptive agents.Blood Coagulation: The process of the interaction of BLOOD COAGULATION FACTORS that results in an insoluble FIBRIN clot.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.ThiophenesAndrostenes: Unsaturated derivatives of the steroid androstane containing at least one double bond at any site in any of the rings.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.Factor 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.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.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.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.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.Risk: The probability that an event will occur. It encompasses a variety of measures of the probability of a generally unfavorable outcome.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.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.Administration, Oral: The giving of drugs, chemicals, or other substances by mouth.AustriaNorpregnenes: Pregnenes with one double bond or more than three double bonds which have undergone ring contractions or are lacking carbon-18 or carbon-19..Contraceptives, Oral, Synthetic: Oral contraceptives which owe their effectiveness to synthetic preparations.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Antithrombin III Deficiency: An absence or reduced level of Antithrombin III leading to an increased risk for thrombosis.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.Arthroplasty, Replacement, Knee: Replacement of the knee joint.Injections, Subcutaneous: Forceful administration under the skin of liquid medication, nutrient, or other fluid through a hollow needle piercing the skin.Atrial Appendage: Ear-shaped appendage of either atrium of the heart. (Dorland, 28th ed)Compression Bandages: Strips of elastic material used to apply pressure to body parts to control EDEMA and aid circulation.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.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)Pyridones: Pyridine derivatives with one or more keto groups on the ring.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)Echocardiography, Transesophageal: Ultrasonic recording of the size, motion, and composition of the heart and surrounding tissues using a transducer placed in the esophagus.Acute Disease: Disease having a short and relatively severe course.Vascular Neoplasms: Neoplasms located in the vasculature system, such as ARTERIES and VEINS. They are differentiated from neoplasms of vascular tissue (NEOPLASMS, VASCULAR TISSUE), such as ANGIOFIBROMA or HEMANGIOMA.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.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.Intracranial Embolism and Thrombosis: Embolism or thrombosis involving blood vessels which supply intracranial structures. Emboli may originate from extracranial or intracranial sources. Thrombosis may occur in arterial or venous structures.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.Blood Coagulation Factors: Endogenous substances, usually proteins, that are involved in the blood coagulation process.Heart Valve Prosthesis: A device that substitutes for a heart valve. It may be composed of biological material (BIOPROSTHESIS) and/or synthetic material.Puerperal Disorders: Disorders or diseases associated with PUERPERIUM, the six-to-eight-week period immediately after PARTURITION in humans.Hospitalization: The confinement of a patient in a hospital.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.Intracranial Thrombosis: Formation or presence of a blood clot (THROMBUS) in a blood vessel within the SKULL. Intracranial thrombosis can lead to thrombotic occlusions and BRAIN INFARCTION. The majority of the thrombotic occlusions are associated with ATHEROSCLEROSIS.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)Arthroplasty, Replacement, Hip: Replacement of the hip joint.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).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.Blood Coagulation Tests: Laboratory tests for evaluating the individual's clotting mechanism.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.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.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.Blood 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.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.Platelet Aggregation Inhibitors: Drugs or agents which antagonize or impair any mechanism leading to blood platelet aggregation, whether during the phases of activation and shape change or following the dense-granule release reaction and stimulation of the prostaglandin-thromboxane system.Inpatients: Persons admitted to health facilities which provide board and room, for the purpose of observation, care, diagnosis or treatment.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.Thrombolytic Therapy: Use of infusions of FIBRINOLYTIC AGENTS to destroy or dissolve thrombi in blood vessels or bypass grafts.Double-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.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)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.Hospital Bed Capacity, 300 to 499Drug Administration Schedule: Time schedule for administration of a drug in order to achieve optimum effectiveness and convenience.PolysaccharidesPhlebitis: Inflammation of a vein, often a vein in the leg. Phlebitis associated with a blood clot is called (THROMBOPHLEBITIS).Orthopedic Procedures: Procedures used to treat and correct deformities, diseases, and injuries to the MUSCULOSKELETAL SYSTEM, its articulations, and associated structures.Guideline Adherence: Conformity in fulfilling or following official, recognized, or institutional requirements, guidelines, recommendations, protocols, pathways, or other standards.Disseminated Intravascular Coagulation: A disorder characterized by procoagulant substances entering the general circulation causing a systemic thrombotic process. The activation of the clotting mechanism may arise from any of a number of disorders. A majority of the patients manifest skin lesions, sometimes leading to PURPURA FULMINANS.Sulfinpyrazone: A uricosuric drug that is used to reduce the serum urate levels in gout therapy. It lacks anti-inflammatory, analgesic, and diuretic properties.MorpholinesThrombin: An enzyme formed from PROTHROMBIN that converts FIBRINOGEN to FIBRIN.Klippel-Trenaunay-Weber Syndrome: A congenital disorder that is characterized by a triad of capillary malformations (HEMANGIOMA), venous malformations (ARTERIOVENOUS FISTULA), and soft tissue or bony hypertrophy of the limb. This syndrome is caused by mutations in the VG5Q gene which encodes a strong angiogenesis stimulator.Postoperative Hemorrhage: Hemorrhage following any surgical procedure. It may be immediate or delayed and is not restricted to the surgical wound.Death, Sudden: The abrupt cessation of all vital bodily functions, manifested by the permanent loss of total cerebral, respiratory, and cardiovascular functions.Tomography, X-Ray Computed: Tomography using x-ray transmission and a computer algorithm to reconstruct the image.Catheterization, Central Venous: Placement of an intravenous CATHETER in the subclavian, jugular, or other central vein.Pulmonary Artery: The short wide vessel arising from the conus arteriosus of the right ventricle and conveying unaerated blood to the lungs.Benzimidazoles: Compounds with a BENZENE fused to IMIDAZOLES.Fibrinogen: Plasma glycoprotein clotted by thrombin, composed of a dimer of three non-identical pairs of polypeptide chains (alpha, beta, gamma) held together by disulfide bonds. Fibrinogen clotting is a sol-gel change involving complex molecular arrangements: whereas fibrinogen is cleaved by thrombin to form polypeptides A and B, the proteolytic action of other enzymes yields different fibrinogen degradation products.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.AzetidinesPredictive 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.Intrauterine Devices, Medicated: Intrauterine devices that release contraceptive agents.Intracranial Embolism: Blocking of a blood vessel in the SKULL by an EMBOLUS which can be a blood clot (THROMBUS) or other undissolved material in the blood stream. Most emboli are of cardiac origin and are associated with HEART DISEASES. Other non-cardiac sources of emboli are usually associated with VASCULAR DISEASES.Fatal Outcome: Death resulting from the presence of a disease in an individual, as shown by a single case report or a limited number of patients. This should be differentiated from DEATH, the physiological cessation of life and from MORTALITY, an epidemiological or statistical concept.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)Fibrinopeptide A: Two small peptide chains removed from the N-terminal segment of the alpha chains of fibrinogen by the action of thrombin during the blood coagulation process. Each peptide chain contains 18 amino acid residues. In vivo, fibrinopeptide A is used as a marker to determine the rate of conversion of fibrinogen to fibrin by thrombin.Angiography: Radiography of blood vessels after injection of a contrast medium.Hemostasis: The process which spontaneously arrests the flow of BLOOD from vessels carrying blood under pressure. It is accomplished by contraction of the vessels, adhesion and aggregation of formed blood elements (eg. ERYTHROCYTE AGGREGATION), and the process of BLOOD COAGULATION.Contraceptives, Oral, Hormonal: Oral contraceptives which owe their effectiveness to hormonal preparations.Registries: The systems and processes involved in the establishment, support, management, and operation of registers, e.g., disease registers.Embolism: Blocking of a blood vessel by an embolus which can be a blood clot or other undissolved material in the blood stream.United StatesEstrogen 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.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.Heart Diseases: Pathological conditions involving the HEART including its structural and functional abnormalities.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)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.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.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.Heart Atria: The chambers of the heart, to which the BLOOD returns from the circulation.Aircraft: 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)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.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.Chronic Disease: Diseases which have one or more of the following characteristics: they are permanent, leave residual disability, are caused by nonreversible pathological alteration, require special training of the patient for rehabilitation, or may be expected to require a long period of supervision, observation, or care. (Dictionary of Health Services Management, 2d ed)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)Pipecolic AcidsEthinyl Estradiol: A semisynthetic alkylated ESTRADIOL with a 17-alpha-ethinyl substitution. It has high estrogenic potency when administered orally, and is often used as the estrogenic component in ORAL CONTRACEPTIVES.Chemoprevention: The use of chemical compounds to prevent the development of a specific disease.Multivariate Analysis: A set of techniques used when variation in several variables has to be studied simultaneously. In statistics, multivariate analysis is interpreted as any analytic method that allows simultaneous study of two or more dependent variables.Pregnancy: The status during which female mammals carry their developing young (EMBRYOS or FETUSES) in utero before birth, beginning from FERTILIZATION to BIRTH.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.Norethynodrel: A synthetic progestational hormone with actions and uses similar to those of PROGESTERONE. It has been used in the treatment of functional uterine bleeding and endometriosis. As a contraceptive, it has usually been administered in combination with MESTRANOL.JapanAutopsy: Postmortem examination of the body.Intracranial Hemorrhages: Bleeding within the SKULL, including hemorrhages in the brain and the three membranes of MENINGES. The escape of blood often leads to the formation of HEMATOMA in the cranial epidural, subdural, and subarachnoid spaces.Sick Sinus Syndrome: A condition caused by dysfunctions related to the SINOATRIAL NODE including impulse generation (CARDIAC SINUS ARREST) and impulse conduction (SINOATRIAL EXIT BLOCK). It is characterized by persistent BRADYCARDIA, chronic ATRIAL FIBRILLATION, and failure to resume sinus rhythm following CARDIOVERSION. This syndrome can be congenital or acquired, particularly after surgical correction for heart defects.Thromboplastin: Constituent composed of protein and phospholipid that is widely distributed in many tissues. It serves as a cofactor with factor VIIa to activate factor X in the extrinsic pathway of blood coagulation.Vena Cava, Inferior: The venous trunk which receives blood from the lower extremities and from the pelvic and abdominal organs.Survival Analysis: A class of statistical procedures for estimating the survival function (function of time, starting with a population 100% well at a given time and providing the percentage of the population still well at later times). The survival analysis is then used for making inferences about the effects of treatments, prognostic factors, exposures, and other covariates on the function.Mitral Valve: The valve between the left atrium and left ventricle of the heart.MassachusettsSagittal Sinus Thrombosis: Formation or presence of a blood clot (THROMBUS) in the SUPERIOR SAGITTAL SINUS or the inferior sagittal sinus. Sagittal sinus thrombosis can result from infections, hematological disorders, CRANIOCEREBRAL TRAUMA; and NEUROSURGICAL PROCEDURES. Clinical features are primarily related to the increased intracranial pressure causing HEADACHE; NAUSEA; and VOMITING. Severe cases can evolve to SEIZURES or COMA.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.DenmarkProgestins: 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.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).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.Heart Valve Diseases: Pathological conditions involving any of the various HEART VALVES and the associated structures (PAPILLARY MUSCLES and CHORDAE TENDINEAE).Evidence-Based Medicine: An approach of practicing medicine with the goal to improve and evaluate patient care. It requires the judicious integration of best research evidence with the patient's values to make decisions about medical care. This method is to help physicians make proper diagnosis, devise best testing plan, choose best treatment and methods of disease prevention, as well as develop guidelines for large groups of patients with the same disease. (from JAMA 296 (9), 2006)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.Thrombocytopenia: A subnormal level of BLOOD PLATELETS.Popliteal Vein: The vein formed by the union of the anterior and posterior tibial veins; it courses through the popliteal space and becomes the femoral vein.Biological Markers: Measurable and quantifiable biological parameters (e.g., specific enzyme concentration, specific hormone concentration, specific gene phenotype distribution in a population, presence of biological substances) which serve as indices for health- and physiology-related assessments, such as disease risk, psychiatric disorders, environmental exposure and its effects, disease diagnosis, metabolic processes, substance abuse, pregnancy, cell line development, epidemiologic studies, etc.Probability: The study of chance processes or the relative frequency characterizing a chance process.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.)Rheumatic Heart Disease: Cardiac manifestation of systemic rheumatological conditions, such as RHEUMATIC FEVER. Rheumatic heart disease can involve any part the heart, most often the HEART VALVES and the ENDOCARDIUM.Lower Extremity: The region of the lower limb in animals, extending from the gluteal region to the FOOT, and including the BUTTOCKS; HIP; and LEG.Bleeding Time: Duration of blood flow after skin puncture. This test is used as a measure of capillary and platelet function.Bioprosthesis: Prosthesis, usually heart valve, composed of biological material and whose durability depends upon the stability of the material after pretreatment, rather than regeneration by host cell ingrowth. Durability is achieved 1, mechanically by the interposition of a cloth, usually polytetrafluoroethylene, between the host and the graft, and 2, chemically by stabilization of the tissue by intermolecular linking, usually with glutaraldehyde, after removal of antigenic components, or the use of reconstituted and restructured biopolymers.Atrial Function, Left: The hemodynamic and electrophysiological action of the LEFT ATRIUM.Fibrin Clot Lysis Time: A measurement of the time needed for FIBRINOLYSIS to occur.Hyperhomocysteinemia: Condition in which the plasma levels of homocysteine and related metabolites are elevated (>13.9 µmol/l). Hyperhomocysteinemia can be familial or acquired. Development of the acquired hyperhomocysteinemia is mostly associated with vitamins B and/or folate deficiency (e.g., PERNICIOUS ANEMIA, vitamin malabsorption). Familial hyperhomocysteinemia often results in a more severe elevation of total homocysteine and excretion into the urine, resulting in HOMOCYSTINURIA. Hyperhomocysteinemia is a risk factor for cardiovascular and neurodegenerative diseases, osteoporotic fractures and complications during pregnancy.Fibrin: A protein derived from FIBRINOGEN in the presence of THROMBIN, which forms part of the blood clot.Prognosis: A prediction of the probable outcome of a disease based on a individual's condition and the usual course of the disease as seen in similar situations.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.beta-Thromboglobulin: A platelet-specific protein which is released when platelets aggregate. Elevated plasma levels have been reported after deep venous thrombosis, pre-eclampsia, myocardial infarction with mural thrombosis, and myeloproliferative disorders. Measurement of beta-thromboglobulin in biological fluids by radioimmunoassay is used for the diagnosis and assessment of progress of thromboembolic disorders.Hypertension, Pulmonary: Increased VASCULAR RESISTANCE in the PULMONARY CIRCULATION, usually secondary to HEART DISEASES or LUNG DISEASES.Leg: The inferior part of the lower extremity between the KNEE and the ANKLE.Thalidomide: A piperidinyl isoindole originally introduced as a non-barbiturate hypnotic, but withdrawn from the market due to teratogenic effects. It has been reintroduced and used for a number of immunological and inflammatory disorders. Thalidomide displays immunosuppressive and anti-angiogenic activity. It inhibits release of TUMOR NECROSIS FACTOR-ALPHA from monocytes, and modulates other cytokine action.Cell-Derived Microparticles: Extracellular vesicles generated by the shedding of CELL MEMBRANE blebs.
Pulmonary angiography: Pulmonary angiography (or pulmonary arteriography) is a cardiological medical procedure. Pulmonary blood vessels are x-rayed to detect arteriovenous malformations.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.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.WarfarinPulmonary hemorrhageD-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.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.Weigh House (Leiden)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.Antithrombotic: An antithrombotic agent is a drug that reduces the formation of blood clots (thrombi).http://cancerweb.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.ThrombusFamilial atrial fibrillation: Familial atrial fibrillation is an autosomal dominant heart condition that causes disruptions in the heart's normal rhythm. This condition is characterized by uncoordinated electrical activity in the heart's upper chambers (the atria), which causes the heartbeat to become fast and irregular.Global 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.Gestational thrombocytopeniaElastic 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.Impedance phlebographyDesogestrelCoagulation testing: Blood clotting tests are the tests used for diagnostics of the hemostasis system.Benzo(c)thiopheneDrospirenoneDarexabanLevonorgestrelOral contraceptive pill: Oral contraceptives, abbreviated OCPs, also known as birth control pills, are medications taken by mouth for the purpose of birth control.National Clinical Guideline CentreNon-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.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.Healthcare 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.GestodeneTemporal analysis of products: Temporal Analysis of Products (TAP), (TAP-2), (TAP-3) is an experimental technique for studyingAntithrombin III deficiencyOxford 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.Subcutaneous injectionLeft atrial appendage occlusionFord Essex V4 engineDrotrecogin alfaAspirinMineral 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.List 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.Transesophageal echocardiogramMedrad Inc.InogatranNested 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.Robot-assisted double heart valve replacement: The first robotic-assisted double heart valve replacement was carried out in the Chennai region of India at Chettinad Hospital. Considered a rare form of surgery, this is the first instance of such a procedure using robotic surgery.Puerperal disorderPartial thromboplastin time: The partial thromboplastin time (PTT) or activated partial thromboplastin time (aPTT or APTT) is a medical test that characterizes blood coagulation.List of kanji by stroke count: This Kanji index method groups together the kanji that are written with the same number of strokes. Currently, there are 2,186 individual kanji listed.Minimally 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 websiteAntiphospholipid syndrome: (ILDS D68.810)Femoral 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.Aafact: Aafact is a monoclonal purified factor VIII concentrate. It consists of a protein fraction prepared from fresh-frozen human plasma.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.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.Scott syndrome: Scott syndrome is a rare congenital bleeding disorder that is due to a defect in a platelet mechanism required for blood coagulation.Weiss HJ.Antithrombin: Antithrombin (AT) is a small protein molecule that inactivates several enzymes of the coagulation system. Antithrombin is a glycoprotein produced by the liver and consists of 432 amino acids.Antiplatelet drug: An antiplatelet drug (antiaggregant) is a member of a class of pharmaceuticals that decrease platelet aggregation and inhibit thrombus formation. They are effective in the arterial circulation, where anticoagulants have little effect.Thrombolytic drug: Thrombolytic drugs are used in medicine to dissolve blood clots in a procedure termed thrombolysis. They limit the damage caused by the blockage or occlusion of a blood vessel.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.
(1/1606) Outcome of pregnancy in women with congenital shunt lesions.
OBJECTIVE: To evaluate the outcome of pregnancy in women with congenital shunt lesions. SETTING: Retrospective study in a tertiary care centre. METHODS: Pregnancy history was obtained by a standardised questionnaire and medical records were reviewed. PATIENTS: 175 women were identified, at a mean (SD) age of 42 (14) years. Pregnancies occurred in 126 women: 50 with an atrial septal defect, 22 with a ventricular septal defect, 22 with an atrioventricular septal defect, 19 with tetralogy of Fallot, and 13 with other complex shunt lesions. RESULTS: 309 pregnancies were reported by 126 woman (2.5 (1.6) pregnancies per woman). The shortening fraction of the systemic ventricle was 40 (8)%, and 98% were in New York Heart Association class I-II at last follow up. Spontaneous abortions occurred in 17% of pregnancies (abortion rate, 0.4 (0.9) per woman). Gestational age of the 241 newborn infants was 8.8 (0.8) months. There were no maternal deaths related to pregnancy. Pre-eclampsia and embolic events were observed in 1.3% and 0.6%, respectively of all pregnancies. Women with complex shunt lesions more often underwent caesarean section (70% v 15-30%, p = 0.005) and gave birth to smaller babies for equivalent gestation (2577 (671) g v 3016 (572) to 3207 (610) g, p < 0.05). The recurrence risk of congenital heart disease was 2.5%. CONCLUSIONS: The outcome of pregnancy is favourable in women with congenital shunt lesions if their functional class and their systolic ventricular function are good. Such patients can be reassured. (+info)
(2/1606) Prospective evaluation of the thrombotic risk in children with acute lymphoblastic leukemia carrying the MTHFR TT 677 genotype, the prothrombin G20210A variant, and further prothrombotic risk factors.
The reported incidence of thromboembolism in children with acute lymphoblastic leukemia (ALL) treated with L-asparaginase, vincristine, and prednisone varies from 2.4% to 11.5%. The present study was designed to prospectively evaluate the role of the TT677 methylenetetrahydrofolate reductase (MTHFR) genotype, the prothrombin G20210A mutation, the factor V G1691A mutation, deficiencies of protein C, protein S, antithrombin, and increased lipoprotein (a) concentrations in leukemic children treated according to the ALL-Berlin-Frankfurt-Muenster (BFM) 90/95 study protocols with respect to the onset of vascular events. Three hundred and one consecutive leukemic children were enrolled in this study. Fifty-five of these 301 subjects investigated had one established single prothrombotic risk factor: 20 children showed the TT677 MTHFR genotype; 5 showed the heterozygous prothrombin G20210A variant; 11 were carriers of the factor V G1691A mutation (heterozygous, n = 10; homozygous, n = 1); 4 showed familial protein C, 4 protein S, and 2 antithrombin type I deficiency; 9 patients were suffering from familially increased lipoprotein (a) [Lp(a)] concentrations (>30 mg/dL). In addition, combined prothrombotic defects were found in a further 10 patients: the FV mutation was combined with the prothrombin G20210A variant (n = 1), increased Lp(a) (n = 3), protein C deficiency (n = 1), and homozygosity for the C677T MTHFR gene mutation (n = 1). Lp(a) was combined with protein C deficiency (n = 2) and the MTHFR TT 677 genotype (n = 2). Two hundred eighty-nine of the 301 patients were available for thrombosis-free survival analysis. In 32 (11%) of these 289 patients venous thromboembolism occurred. The overall thrombosis-free survival in patients with at least one prothrombotic defect was significantly reduced compared with patients without a prothrombotic defect within the hemostatic system (P <.0001). In addition, a clear-cut positive correlation (P <.0001) was found between thrombosis and the use of central lines. However, because the prothrombotic defects diagnosed in the total childhood population studied were all found within the prevalences reported for healthy Caucasian individuals, the interaction between prothrombotic risk factors, ALL treatment, and further environmental factors is likely to cause thrombotic manifestations. (+info)
(3/1606) Bileaflet mechanical prostheses for aortic valve replacement in patients younger than 65 years and 65 years of age or older: major thromboembolic and hemorrhagic complications.
OBJECTIVE: To determine major thromboembolic and hemorrhagic complications and predictive risk factors associated with aortic valve replacement (AVR), using bileaflet mechanical prostheses (CarboMedics and St. Jude Medical). DESIGN: A case series. SETTING: Cardiac surgical services at the teaching institutions of the University of British Columbia. PATIENTS AND METHODS: Patients 2 age groups who had undergone AVR between 1989 and 1994 were studied. Group 1 comprised 384 patients younger than 65 years. Group 2 comprised 215 patients 65 years of age and older. RESULTS: The linearized rates of major thromboembolism (TE) occurring after AVR were 1.54%/patient-year for group 1 and 3.32%/patient-year for group 2; the rates for major TE occurring more than 30 days after AVR were 1.13%/patient-year for group 1 and 1.55%/patient-year for group 2. The crude rates for major TE occurring within 30 days of AVR were 1.04% for group 1 and 3.72% for group 2. The death rate from major TE in group 1 was 0.31%/patient-year and in group 2 was 0.88%/patient-year. Of the major TE events occurring within 30 days, 100% of patients in both age groups were inadequately anticoagulated at the time of the event, and for events occurring more than 30 days after AVR, 45% in group 1 and 57% in group 2 were inadequately anticoagulated (INR less than 2.0). The overall linearized rates of major hemorrhage were 1.54%/patient-year for group 1 and 2.21%/patient-year for group 2. There were no cases of prosthesis thrombosis in either group. The mean (and standard error) overall freedom from major TE for group 1 patients at 5 years was 95.6% (1.4%) and with exclusion of early events was 96.7% (1.3%); for group 2 patients the rates were 90.0% (3.2%) and 93.7% (3.0%), respectively. The mean (and SE) overall freedom from major and fatal TE and hemorrhage for group 1 patients was 90.1% (2.3%) and with exclusion of early events was 91.2% (2.3%); for group 2 patients the rates were 87.9% (3.1%) and 92.5% (2.9%), respectively. The 5-year rate for freedom from valve-related death for group 1 patients was 96.3% (2.1%) and for group 2 patients was 97.2% (1.2%). CONCLUSION: The thromboembolic and hemorrhagic complications after AVR with bileaflet mechanical prostheses occur more frequently and result in more deaths in patients 65 years of age and older than in patients years younger than 65 years. (+info)
(4/1606) Single and combined prothrombotic factors in patients with idiopathic venous thromboembolism: prevalence and risk assessment.
The inherited thrombophilias--deficiencies of protein C, protein S, and antithrombin III--and the prothrombotic polymorphisms factor V G1691A and factor II G20210A predispose patients toward venous thromboembolism (VTE). The aim of this study was to determine the prevalence of single and combined prothrombotic factors in patients with idiopathic VTE and to estimate the associated risks. The study group consisted of 162 patients referred for work-up of thrombophilia after documented VTE. The controls were 336 consecutively admitted patients. In all subjects factor V G1691A, factor II G20210A, and methylenetetrahydrofolate reductase (MTHFR) C677T were analyzed by specific polymerase chain reactions and restriction enzymes. Activities of antithrombin III and protein C, free protein S antigen, and lupus anticoagulant were determined in a subset of 109 patients who were not receiving oral anticoagulants. The prevalences of heterozygotes and homozygotes for factor V G1691A and factor II G20210A among patients and controls were 40.1% versus 3.9% and 18.5% versus 5.4%, respectively (P=0.0001). The prevalence of homozygotes for MTHFR C677T in patients was 22.8% and in controls, 14.3% (P=0.025). Heterozygous and homozygous factor V G1691A, factor II G20210A, and homozygous MTHFR C677T were found to be independent risk factors for VTE, with odds ratios of 16.3, 3.6, and 2.1, respectively. Two or more polymorphisms were detected in 27 of 162 patients (16.7%) and in 3 of 336 controls (0.9%). Logistic regression analysis disclosed odds ratios of 58.6 (confidence interval [CI], 22.1 to 155.2) for joint occurrence of factor V and factor II polymorphisms, of 35.0 (CI, 14.5 to 84.7) for factor V and MTHFR polymorphisms, and of 7.7 (CI, 3.0 to 19.6) for factor II and MTHFR polymorphisms. Among 109 patients in whom a complete thrombophilic work-up was performed, 74% had at least 1 underlying defect. These data indicate that in most patients referred for evaluation of thrombophilia due to idiopathic VTE, 1 or more underlying genetic predispositions were discernible. The presence of >1 of the prothrombotic polymorphisms was associated with a substantial risk of VTE. (+info)
(5/1606) Pulmonary embolism: one-year follow-up with echocardiography doppler and five-year survival analysis.
BACKGROUND: The long-term prognosis for patients with pulmonary embolism (PE) is dependent on the underlying disease, degree of pulmonary hypertension (PH), and degree of right ventricular (RV) dysfunction. A precise description of the time course of pulmonary artery pressure (PAsP)/RV function is therefore of importance for the early identification of persistent PH/RV dysfunction in patients treated for acute PE. Other objectives were to identify variables associated with persistent PH/RV dysfunction and to analyze the 5-year survival rate for patients alive 1 month after inclusion. METHODS AND RESULTS: Echocardiography Doppler was performed in 78 patients with acute PE at the time of diagnosis and repeatedly during the next year. A 5-year survival analysis was made. The PAsP decreased exponentially until the beginning of a stable phase, which was =38 days. The recovery of RV function occurred during the same time period. Risk factors for persistent PH/RV dysfunction and the 5-year mortality rate were analyzed using multiple logistic regression models. A PAsP of >50 mm Hg at the time of diagnosis of acute PE was associated with persistent PH after 1 year. The 5-year mortality rate was associated with underlying disease. Only patients with persistent PH in the stable phase required pulmonary thromboendarterectomy within 5 years. CONCLUSIONS: An echocardiography Doppler investigation performed 6 weeks after diagnosis of acute PE can identify patients with persistent PH/RV dysfunction and may be of value in planning the follow-up and care of these patients. (+info)
(6/1606) In vivo targeting of acoustically reflective liposomes for intravascular and transvascular ultrasonic enhancement.
OBJECTIVES: The purpose of this study was to target acoustically reflective liposomes to atherosclerotic plaques in vivo for ultrasound image enhancement. BACKGROUND: We have previously demonstrated the development of acoustically reflective liposomes that can be conjugated for site-specific acoustic enhancement. This study evaluates the ability of liposomes coupled to antibodies specific for different components of atherosclerotic plaques and thrombi to target and enhance ultrasonic images in vivo. METHODS: Liposomes were prepared with phospholipids and cholesterol using a dehydration/ rehydration method. Antibodies were thiolated for liposome conjugation with N-succinimidyl 3-(2-pyridyldithio) propionate resulting in a thioether linkage between the protein and the phospholipid. Liposomes were conjugated to antifibrinogen or anti-intercellular adhesion molecule-1 (anti-ICAM-1). In a Yucatan miniswine model, atherosclerosis was developed by crush injury of one carotid and one femoral artery and ingestion of a hypercholesterolemic diet. After full plaque development the arteries were imaged (20-MHz intravascular ultrasound catheter and 7.5-MHz transvascular linear probe) after injection of saline, unconjugated liposomes and antibody conjugated liposomes. RESULTS: Conjugated liposomes retained their acoustically reflective properties and provided ultrasonic image enhancement of their targeted structures. Liposomes conjugated to antifibrinogen attached to thrombi and fibrous portions of the atheroma, whereas liposomes conjugated to anti-ICAM-1 attached to early atheroma. CONCLUSIONS: Our data demonstrate that this novel acoustic agent can provide varying targeting with different antibodies with retention of intravascular and transvascular acoustic properties. (+info)
(7/1606) A comparison of three months of anticoagulation with extended anticoagulation for a first episode of idiopathic venous thromboembolism.
BACKGROUND: Patients who have a first episode of venous thromboembolism in the absence of known risk factors for thrombosis (idiopathic thrombosis) are often treated with anticoagulant therapy for three months. Such patients may benefit from longer treatment, however, because they appear to have an increased risk of recurrence after anticoagulant therapy is stopped. METHODS: In this double-blind study, we randomly assigned patients who had completed 3 months of anticoagulant therapy for a first episode of idiopathic venous thromboembolism to continue receiving warfarin, with the dose adjusted to achieve an international normalized ratio of 2.0 to 3.0, or to receive placebo for a further 24 months. Our goal was to determine the effects of extended anticoagulant therapy on rates of recurrent symptomatic venous thromboembolism and bleeding. RESULTS: A prespecified interim analysis of efficacy led to the early termination of the trial after 162 patients had been enrolled and followed for an average of 10 months. Of 83 patients assigned to continue to receive placebo, 17 had a recurrent episode of venous thromboembolism (27.4 percent per patient-year), as compared with 1 of 79 patients assigned to receive warfarin (1.3 percent per patient-year, P<0.001). Warfarin resulted in a 95 percent reduction in the risk of recurrent venous thromboembolism (95 percent confidence interval, 63 to 99 percent). Three patients assigned to the warfarin group had nonfatal major bleeding (two had gastrointestinal bleeding and one genitourinary bleeding), as compared with none of those assigned to the placebo group (3.8 vs. 0 percent per patient-year, P=0.09). CONCLUSIONS: Patients with a first episode of idiopathic venous thromboembolism should be treated with anticoagulant agents for longer than three months. (+info)
(8/1606) Arterial thromboembolism in patients with sick sinus syndrome: prediction from pacing mode, atrial fibrillation, and echocardiographic findings.
OBJECTIVE: To evaluate whether thromboembolism in sick sinus syndrome can be predicted by pacing mode, atrial fibrillation, or echocardiographic findings. METHODS: Patients were randomised to single chamber atrial (n = 110) or ventricular (n = 115) pacing. They were divided into subgroups with and without brady-tachy syndrome at time of randomisation. The occurrence of atrial fibrillation and thromboembolism during follow up were investigated and compared with echocardiographic findings. RESULTS: The annual risk of thromboembolism was 5.8% in patients with brady-tachy syndrome randomised to ventricular pacing, 3.2% in patients without brady-tachy syndrome randomised to ventricular pacing, 3% in patients with brady-tachy syndrome randomised to atrial pacing, and 1.5% in patients without brady-tachy syndrome randomised to atrial pacing. In atrial paced patients without brady-tachy syndrome at randomisation and without atrial fibrillation during follow up, the annual risk of thromboembolism was 1.4%. Left atrial size measured by M mode echocardiography was of no value in predicting thromboembolism. CONCLUSIONS: Arterial thromboembolism in patients with sick sinus syndrome is very common and is associated primarily with brady-tachy syndrome at randomisation and with ventricular pacing. The risk of thromboembolism is small in atrial paced patients in whom atrial fibrillation has never been documented. (+info)
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