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Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Plasma antithrombin III (AT III) level was examined in 30 pregnant women with hypertension and 44 without hypertension. AT III level is significatively lower in the group of hypertension. The degree of reduction in plasma AT III level seems to be correlated with hyper uricemia but not with count of platelets or fibrinogen.
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PMID:[A study of the mean concentration of plasma antithrombin III in arterial hypertension in pregnancy]. 653 44

In 57 patients with pregnancy-induced or aggravated hypertension, antithrombin III levels correlated inversely with maternal morbidity. Morbidity was determined by the maximal diastolic blood pressure, disturbance of renal and liver function, and thrombocytopenia. Antithrombin III levels and platelet counts correlated inversely with the degree of placental infarction. Proteinuria (grams per 24 hours) was most predictive of fetal outcome, which was considered to be either favorable if a healthy baby could be discharged with its mother or unfavorable in case of perinatal death or a prolonged stay in the neonatal intensive care unit. Plasma antithrombin III and serum glutamic oxaloacetic transaminase levels, in that order, augmented the number of correct predictions. Antithrombin III inhibits blood coagulation by forming irreversible complexes with activated clotting enzymes, notably with factor Xa and thrombin. Evidence is presented which suggests that antithrombin III levels in preeclampsia are depressed as a result of increased consumption in the maternal vascular tree, rather than decreased synthesis or increased urinary loss.
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PMID:Antithrombin III levels in preeclampsia correlate with maternal and fetal morbidity. 671 44

Thrombus formation depends on adherence of blood-formed elements to the intimal surface through platelet-vessel surface interaction, platelet release phenomena and aggregation, formation of fibrin, and the enmeshing of blood cells. Arterial thrombi involve platelet aggregation, whereas venous thrombi found in low flow or during stasis have greater proportions of erythrocytes and fibrin. It is not known if or how abnormalities of flow resistance, platelet thrombus formation, or endothelial and dynamic parameters affect the microcirculation, largely due to the difficulty of obtaining comprehensive data from these systems. Increases of fibrinogen observed in many disorders may result in minor changes in blood viscosity without known physiologic consequence, but in most disorders in which thrombosis is observed, the pathophysiologic mechanisms are multifactorial and abnormal blood viscosity is presumed to be a significant but not limiting component. Therapeutic approaches in thrombotic disorders should recognize which elements of the thrombotic triad predominate. In arterial disorders focus should be on platelet activity, and the objectives of venous thrombosis treatment include prevention of morbidity and death from pulmonary embolism, reduction of morbidity resulting from the acute thrombotic episode, and prevention of the postphlebitic syndrome. Pathology, mechanism, and treatment for specific thrombogenic disorders are described. Treatments suggested for hyperviscosity involve giving antibiotics during crises. Also discussed are thalassemia, paroxysomal nocturnal hemoglobinuria, polycythemia, cryoglobulinemia, paraproteinemia, diabetes mellitus, and disseminated intravascular coagulation. Studies have established a relationship between thromboembolic disease and oral contraceptives (OCs). The risk is only increased while the patient is taking OCs but is compounded in women undergoing surgery or who have a disorder which predisposes to venous disease. The risk for myocardial infarction or stroke is significantly increased when OCs are taken over age 35 and when there is hypertension, smoking, type-II hyperlipoproteinemia, and diabetes mellitus. The risk appears to be a function of estrogen dosage, causing a 25% mean increase in calf venous volume and 30% decrease in vein velocity of venous blood compared to controls. Low flow rates may contribute to venous thromboembolism. OCs may alter precisely regulated systems of coagulation and fibrinolysis and recent studies confirm abnormalities in the hemostatic system attributed to OCs. 16% of women taking OCs have a 60% or greater reduction in antithrombin III activity. The multiple effects of OCs often result in low-grade activation of the hemostatic system, potentially lowering the threshold to precipitate thrombus formation and possibly explaining the increased incidence of thromboembolic disease. Heparin appears to reverse many of these problems.
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PMID:Blood viscosity and thrombosis: clinical considerations. 676 12

The incidence of thromboses among young women has increased with widespread use of oral contraceptives (OCs) due to the significant thromboembolic risk of estrogen. Estrogens intervene at the vascular, platelet, and plasma levels as a function of hormonal variations in the menstrual cycle, increasing the aggregability of the platelets and thrombocytes, accelerating the formation of clots, and decreasing the amount of antithrombin III. Estrogens are used in medicine to treat breast and prostate cancers and in gynecology to treat dysmenorrhea, during the menopause, and in contraception. Smoking, cardiovascular disease and hypertension, hypercholesterolemia, and diabetes are contraindicators to estrogen use. Thrombosis refers to blockage of a blood vessel by a clot or thrombus. Before estrogens are prescribed, a history of phlebitis, obesity, hyperlipidemia, or significant varicosities should be ruled out. A history of venous thrombosis, hyperlipoproteinemia, breast nodules, serious liver condition, allergies to progesterone, and some ocular diseases of vascular origin definitively rule out treatment with estrogens. A family history of infarct, embolism, diabetes, cancer, or vascular accidents at a young age signals a need for greater patient surveillance. All patients receiving estrogens should be carefully observed for signs of hypertension, hypercholesterolemia, hypercoagulability, or diabetes. Nurses have a role to play in carefully eliciting the patient's history of smoking, personal and family medical problems, and previous and current laboratory results, as well as in informing the patients of the risks and possible side effects of OCs, especially for those who smoke. Nurses should educate patients receiving estrogens, especially those with histories of circulatory problems, to avoid standing in 1 position for prolonged periods, avoid heat which is a vasodilator, avoid obesity, excercise regularly, wear appropriate footgear, and follow other good health practices.
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PMID:[Estrogens and vascular thrombosis]. 692 85

Plasma antithrombin III (AT III) activity was examined retrospectively in patients with preeclampsia-eclampsia, chronic hypertension, and chronic hypertension with superimposed preeclampsia-eclampsia. Levels of AT III were greater than 1 SD below normal pregnant control in each case of preeclampsia-eclampsia syndrome. The degree of reduction in plasma AT III activity was correlated with the severity of disease. AT III activity was within normal limits in patients with chronic hypertension. AT III activity dropped prior to the appearance of clinically evident disease in three patients who were followed from an early gestational age. In no instance was low plasma AT III activity associated with normal pregnancy. Coincidental disease, including pyelonephritis and a viral syndrome, were associated with markedly decreased levels of plasma AT III activity in otherwise normal pregnancies. Plasma AT III activity may be valuable as a tool in diagnosing preeclampsia-eclampsia, as a screening test for preclinical preeclampsia-eclampsia, and as an indicator of severity of disease.
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PMID:Plasma antithrombin III activity: an aid in the diagnosis of preeclampsia-eclampsia. 706 16

Thrombelastography in the whole blood and determination of antithrombin III by means of chromogenic substrates were performed in a group of 10 patients with hypertension. The results of the thrombelastograms showed a slight shift toward hypercoagulability, as revealed by a significant increase in the thrombodynamic potential index. There was no significant change in antithrombin activity as compared with control group.
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PMID:[Coagulation parameters in patients with hypertension]. 714 84

The correlation between elevated serum lipids, shortened coagulation time, and the accelerated thrombosis measured in vivo was found in experimental animals. Elevated levels of some coagulation factors were found in samples of human hyperlipoproteinemic plasma. Experimental hypertension induced significant rise of serum cholesterol and some coagulation factors also. If thrombosis is important in the genesis of atheroclerosis, these findings could indicate that elevation of plasma lipids may play a role, via the coagulation pathway, in the production of human vascular disease. These findings encouraged us to test the group of patients with rised blood pressure and to correlate their lipid and coagulation status. Statistically significant difference between hyperlipemia and normolipemic hypertonics was seen in level of factors V and VII reduced fibrinolytic activity, decreased antithrombin III, and in higher rate of hypercoagulabilic thromboelastograms.
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PMID:[Signs of hypercoagulability in hyperlipemic hypertensives]. 733 84

To assess hemostatic risk factors for sudden death in patients with stable angina, 323 consecutive patients were recruited prospectively. Patients with clinical heart failure or recent myocardial infarction were excluded. The following clinical variables were recorded: age, gender, smoking habits, hypertension, previous myocardial infarction, left ventricular hypertrophy, and severe ventricular arrhythmia. Angiographic variables included coronary extent, assessed from Jenkins' and mean atherosclerotic scores, and left ventricular ejection fraction. Lipid variables included total cholesterol, triglycerides, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, and apolipoproteins A-I and B. Hemostatic factors included fibrinogen, fibrinopeptide A, antithrombin III, factor VIII antigen, factor VIII coagulant, protein C, plasminogen, alpha 2 antiplasmin, euglobulin clot lysis time, tissue plasminogen activator before and after venous occlusion, and plasminogen activator inhibitor. There were 34 deaths, 19 of which were sudden during the follow-up period (60 +/- 17 months). The association between each variable and the risk of sudden death was assessed by calculating the relative risk with the Cox univariate model. All significant predictors from the univariate analysis were then incorporated in a Cox multivariate model to select the independent predictors of sudden death. The independent predictors of sudden death were left ventricular hypertrophy (p < 0.04), lower left ventricular ejection fraction (p < 0.04), and shorter euglobulin clot lysis time after venous occlusion (p < 0.02), whereas fibrinogen (p < 0.07) and Jenkins' score (p < 0.08) were borderline. Determination of hemostatic variables, especially those pertaining to dynamic fibrinolysis, may thus be of value in assessing risk of sudden death.
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PMID:Predictive value of hemostatic factors for sudden death in patients with stable angina pectoris. 761 16

Recent cohort and case control studies of low-dose combined oral contraceptives (COCs) containing the new generation of progestogens have allowed classification of adverse effects into those which are rare but serious and should be considered risks and those which are more frequent but are less of a threat to health. Low-dose COCs continue to affect coagulation in a complex way, but the risk is less than with the older preparations, and it can be minimized by screening women for a personal or familial history of early or unusual thrombosis and for levels of protein C, S, and antithrombin III. Women with true migraine with focal signs should also avoid using COCs. The relative risk of myocardial infarction (MI) may increase from 4:1 in women with one risk factor (age, smoking, hypertension, hyperlipidemia, and diabetes) to 20:1 with two risk factors and 128:1 with three or more risk factors. In the absence of all risk factors, a recent study indicated that the relative risk of MI with COC use was 1.9 for current and past use. COC use also causes a slight increase in hypertension in most women, especially those who are older or have a family history of hypertension. While the COC can affect carbohydrate and lipid metabolism, the new generation of progestogens has reduced these effects. The COC may accelerate presentation of gallbladder disease in predisposed women. The COC protects against benign breast disease but may increase the risk of breast cancer and cervical cancer slightly. There is a strong link between hepatocellular adenoma and COC use, but the incidence is low. Return to fertility after use has not been a problem. Both estrogenic adverse effects (nausea, dizziness, irritability, weight gain, bloating) and progestogenic adverse effects (vaginal dryness, acne, hirsutism, weight gain, depression, loss of libido) can occur in 50% of women, but these generally disappear after a few months of use. In conclusion, the low-dose, third generation COCs are associated with minimal risks in the absence of other risk factors and have many beneficial effects such as the prevention of ovarian and endometrial cancer; a decrease in pelvic inflammatory disease and ectopic pregnancies; and protection from anemia, primary dysmenorrhea, functional ovarian cysts, and benign breast disease as well as from the morbidity and mortality associated with pregnancy.
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PMID:The combined oral contraceptive. Risks and adverse effects in perspective. 776 40

The diagnosis of preeclampsia, with all of its consequences, is at times difficult to establish, especially when the patient has underlying chronic hypertension and is not known from prior prenatal care visits. Many screening tests have been proposed. These should be sensitive, relatively specific, easy to perform, of low cost, and have a reasonable interval from prediction to disease onset. Laboratory assays would obviously be useful. We evaluated hemostasis tests for the diagnosis of preeclampsia, and compared fibronectin, antithrombin III and alpha 2-antiplasmin in 48 preeclamptics and 86 control nulliparas. Receive operator characteristic (ROC) curve analysis suggested that fibronectin is the most effective of these tests. A similar analysis comparing the results of previous studies using serum iron, angiotensin infusion, urinary calcium/creatinine ratio, the rollover test and uric acid suggested a possible role for fibronectin in the diagnosis of preeclampsia. While not ideal, there seems to be, at present, no other, easy to perform laboratory test that outperforms fibronectin in predicting preeclampsia.
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PMID:Hemostasis and diagnosis of preeclampsia. 797 90


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