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

The clinical course of the haemolytic-uraemic syndrome in four patients suggests that hypertension may result from it. The morphological changes in the kidney are those of primary malignant nephrosclerosis. Hypercoagulability is thought to be an important pathogenetic factor in the development of the disease. But irreversible renal failure is not, contrary to typical primary malignant nephrosclerosis, an inevitable sequel. Abortive forms with predominant involvement of glomerular vessels have a more favourable prognosis than those forms with additional preglomerular vascular changes, in which a more or less marked impairment of renal function and hypertension persists. These forms are of particular interest because they indicate a renal pathogenetic mechanism of chronic hypertension. The described observations--taken together with those on the pathogenesis of hypertension caused by oral contraceptives--provide a pointer to the importance of clotting disorders in the initiation and development of some forms of hypertension.
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PMID:[Are clotting disorders a pathogenetic factor in nephrosclerosis and hypertension? (author's transl)]. 63 Oct 40

This study prospectively evaluates hypercoagulable states in patients under 51 years of age undergoing lower extremity revascularization for ischemia and assesses early outcome after operation. Twenty patients whose ages range from 23 to 50 years (mean 40.8 years) were identified prospectively who underwent lower extremity revascularization and evaluation of hypercoagulability. Fifteen patients were male (75%), 10 were black (50%), six had hypertension (30%), and four were diabetic (20%). All but two were cigarette smokers (90%). Seven aortoiliac procedures and 13 infrainguinal procedures were performed. Six patients had one or more abnormalities of regulatory proteins (protein S deficiency, four; protein C deficiency, three; presence of lupus-like anticoagulant, three; plasminogen deficiency, two). Eight of 17 patients in whom platelet aggregation profiles were obtained showed increased reactivity (47%). Only 4 of 17 patients (24%) were normal when tested for all parameters. Arterial or graft thrombosis developed in four of the 20 patients within 30 days after operation. Hypercoagulability was found in all four patients whose revascularizations failed. A high incidence of hypercoagulable states was found in patients under 51 years of age with lower limb ischemia requiring revascularization. Hypercoagulability may have contributed to early postoperative thrombosis of the vascular procedure.
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PMID:Hypercoagulable states and lower limb ischemia in young adults. 252 8

A retrospective community-wide survey identified 109 patients younger than 40 years of age with lower extremity ischemia: 72 men and 37 women, mean age 36 years (range 25 to 40 years), black-to-white ratio-1:1. Initially, 66 patients had claudication and 43 had severe ischemia. Cardiovascular risk factors were smoking (85%), hypertension (47%), coronary artery disease (30%), hyperlipidemia (27%), diabetes (25%), and visceral arteriopathy (17%). Unique risk factors included hypercoagulability (15%) and clinical arterial hypoplasia (15%). Twenty-three (21%) patients were treated medically; 74 (68%) underwent primary revascularization and 12 (11%) primary major limb amputation. Forty-six (53%) patients required secondary procedures, of which 34 (74%) were performed within 1 year of primary intervention. A total of 29 (27%) patients ultimately required amputation (10 bilateral). Women had higher prevalence of diabetes (p < 0.01), arterial hypoplasia (p < 0.05), and tendency for more severe ischemia (p = 0.11). No racial differences in severity of symptoms or outcome of treatment were found. By multiple logistic regression analysis, typical cardiovascular risk factors did not predict severity of symptoms, need for surgical treatment, or outcome. However, diabetes was associated with tissue loss (p < 0.05) and primary amputation (p < 0.001). Further, adjusted odds ratios indicate that arterial hypoplasia had a protective effect on distal vasculature (p < 0.05) and predicting need for revascularization (p < 0.05), but not on treatment failure. Hypercoagulability had the highest predictive value for presence of severe ischemia (p < 0.05), need for primary amputation (p < 0.01), and early failure of surgical treatment (p < 0.05).
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PMID:Lower extremity ischemia in adults younger than forty years of age: a community-wide survey of premature atherosclerotic arterial disease. 817 42

Thrombophilia may cause thrombotic venous occlusion in the femoral head, with venous hypertension and hypoxic bone death, leading to Legg-Perthes disease. Resistance to activated protein C, the most common thrombophilic trait, was measured in 64 children with Legg-Perthes disease. Genomic deoxyribonucleic acid was studied to delineate the CGA-->CAA substitution at position 1691 of the Factor V Leiden gene responsible for resistance to activated protein C. The activated protein C ratio was calculated by dividing clotting time obtained with activated protein C-calcium chloride by clotting time obtained with calcium chloride alone. Resistance to activated protein C, with a low activated protein C ratio (less than 2.19, the 5th percentile for 160 normal pediatric controls) was the most common coagulation defect, found in 23 of 64 children with Legg-Perthes disease versus 7 of 160 pediatric controls. Eight of 64 children with Legg-Perthes disease had a low activated protein C ratio and the mutant Factor V gene (7 heterozygotes, 1 homozygote) versus 1 of 101 normal pediatric controls. Two or 3 generation vertical and horizontal transmission of heterozygosity for the mutant Factor V gene was found in 4 of the 8 kindreds. Of 64 children with Legg-Perthes disease, only 14 (22%) had entirely normal coagulation measures. Resistance to activated protein C appears to be a pathogenetic cause of Legg-Perthes disease.
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PMID:Resistance to activated protein C and Legg-Perthes disease. 1037 32

Thrombophilia is now considered a multicausal disease, with an interplay of acquired and genetic risk factors. Recent studies have shown that patients with the 20210 A prothrombin mutation display remarkably similar characteristics compared with patients with Factor V Leiden mutation. It is evident that neither the Factor V Leiden mutation nor the 20210 A prothrombin mutation is a major risk factor for myocardial infarction or stroke, unless accompanied by other classical risk factors, including diabetes mellitus, hypertension and smoking. Finally, the homozygous form of the thermolabile methylenetetrahydrofolate reductase gene, although leading to elevated homocysteine levels, seems not to represent a genetic risk factor for venous thrombosis.
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PMID:Thrombophilia. 1046 43

Thrombophilia with a contemporary reduction of fibrinolytic activity has been observed both in diabetes mellitus and hypertension. Previously, we found a relationship between plasminogen activator inhibitor Type 1 (PAI-1) and lipoprotein(a) [Lp(a)] in Type 2 diabetes mellitus patients without complications. We hypothesised that this relationship could be due to a compensatory mechanism able to lower the risk of hypofibrinolysis as found in Type 2 diabetes mellitus. The present work was aimed at investigating the influence of concurrent hypertension and diabetes mellitus on the plasma levels of these two fibrinolytic inhibitors. In addition, other risk factors, known to influence the fibrinolytic parameters, were taken into account. Forty-nine Type 2 nonhypertensive diabetic patients without complications, 47 Type 2 hypertensive diabetic patients without complications, 54 non-diabetic hypertensive subjects without complications as well as 87 control subjects were studied. Plasma concentrations of Lp(a), PAI-1 antigen and activity, and the main parameters of oxidative, lipo- and glycometabolic balance were determined. Significant statistical differences between diabetic and non-diabetic subjects were found concerning triglycerides and antioxidant defence (p<0.01). Analysis of variance showed the F test statistically significant in evaluating the Log PAI-1/Lp(a) (p = 0.02). Correlation analysis between Log PAI-1 antigen and Lp(a) was significant in non-hypertensive diabetic patients, as expected (r = -0.38, p<0.01), and even stronger in hypertensive diabetic patients (r = -O.72,p<0.01). These results allow to hypothesise that the relationship between PAI-1/Lp(a) could be determinant in avoiding vascular complications due to diabetes mellitus and hypertension.
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PMID:A strong inverse relationship between PAI-1 and Lp(a) in hypertensive Type 2 diabetic patients. 1078 61

The major side effects due to estrogens in oral contraceptives are summarized, (thromboembolism, hypertension, diabetes, lipid metabolism, liver function) 2 retrospective studies on thromboembolism are reviewed. Estrogens decrease bile flux in the liver, which can become manifest as jaundice or pruritus, and may be the cause of abnormal synthesis of proteins by the liver. Glucose tolerance decreases and insulinemia rises in 30% of users after 2 years and in 80% after 5 years, often revealing latent diabetes or causing obesity. Plasma fatty acids and triglycerides increase, and in the predisposed, hyperlipidemia may appear. Hypercoagulability results from increased synthesis of clotting factors by the liver and thromboembolism may become more likely because of hypertension, obesity and lesions in the veins. Hypertension seems due to increased output of angiotensinogen by the liver and aldosterone by the adrenal. A British retrospective study on less than 10% of known thromboembolism cases implicates estrogen doses above 50 mcg, but found several contradictions.
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PMID:[Are estrogens responsible for incidents observed under combined estrogen-progestagen treatment?]. 1230 14

The role of thrombophilia in the pathogenesis of preeclampsia is controversial. The aim of this case-controlled study was to determine whether thrombophilia increases the risk of preeclampsia or interferes with its clinical course. A total of 808 white patients who developed preeclampsia (cases) and 808 women with previous uneventful pregnancies (controls) matched for age and parity were evaluated for inherited and acquired thrombophilia (factor V Leiden; factor II G20210A; methylenetetrahydrofolate reductase C677T; protein S, protein C, and antithrombin III deficiency; anticardiolipin antibodies; lupus anticoagulant; and hyperhomocysteinemia). Odds ratios (ORs) with 95% confidence intervals (CIs) for risk of being carriers of thrombophilia in cases compared with controls and for risk of maternal life-threatening complications and adverse perinatal outcomes in preeclamptic patients with or without thrombophilia were calculated. Women with severe preeclampsia (406 cases) had a higher risk (OR, 4.9; 95% CI, 3.5 to 6.9) of being carriers of either an inherited or acquired thrombophilic factor, except for protein S, protein C, and antithrombin deficiency. In women with mild preeclampsia (402 cases), only prothrombin and homozygous methylenetetrahydrofolate reductase gene mutations were significantly more prevalent than in the controls. Thrombophilic patients with severe preeclampsia are at increased risk of acute renal failure (OR, 1.8; 95% CI, 1.5 to 2.2), disseminated intravascular coagulation (OR, 2.7; 95% CI, 1.1 to 6.4), abruptio placentae (OR, 2.6; 95% CI, 1.2 to 6.0) and perinatal mortality (OR, 1.7; 95% CI, 1.5 to 2.2) compared with nonthrombophilic preeclamptic patients. Our study demonstrates a significant association between maternal thrombophilia and severe preeclampsia in white women. Thrombophilia also augments the risk of life-threatening maternal complications and adverse perinatal outcomes in preeclamptic patients.
Hypertension 2005 Dec
PMID:Thrombophilia is significantly associated with severe preeclampsia: results of a large-scale, case-controlled study. 1628 82

A new hypothesis is presented on the function of factor XII, which is postulated to be a "missing link" between acute stress and transient hypercoagulability. The implications of this idea are developed to show how chronic stress, which involves activation of hypertension and migraine as well as hypercoagulability, can cause of cerebrovascular disease. "Acute stress" is defined as "the normal short-term physiological response to the perception of major threats or demands". "Chronic stress" is "the abnormal ongoing physiological response to the continuing perception of unresolvable major threats or demands". The factor XII hypothesis is as follows: Acute stress includes release of epinephrine by the adrenal medulla. Epinephrine activates platelets by binding to alpha-2A adrenergic receptors. Activated platelets convert pre-bound factor XII to its active form, which then initiates the intrinsic coagulation cascade. This can be called the "activated platelet initiation pathway" for coagulation. Neither tissue factor nor pre-formed thrombin is required. Thrombosis proceeds to completion, but only a minute amount of thrombin is formed, and the process normally stops at this point. In people who lapse into a state of chronic stress, essential hypertension, which is also a manifestation of stress, synergizes with hypercoagulability: there is both a baseline rise in blood pressure and systemic platelet activation as well as superimposed labile rises of both. Upregulation of these two stress parameters is atherogenic: epinephrine-activated platelets stimulating thrombin formation interact with endothelial cells activated by angiotensin II to cause, first, smooth muscle cell proliferation, which is a histological hallmark of atherosclerosis, and, lastly, a symptomatic thrombotic occlusion-the stroke. The migraine symptoms which often accompany this process are a marker of chronic stress and ongoing pathophysiologic damage. Therapeutic predictions are made regarding novel ways of blocking stress-induced hypercoagulability and hypertension. Hypercoagulability could be targeted by monoclonal antibodies directed against the platelet-specific alpha-2 adrenergic receptor or the (putative) platelet receptor for Factor XII; hypertension could be treated with monoclonal antibodies directed against the beta-adrenergic receptor in the juxtaglomerular apparatus or by surgical denervation of the kidneys, either of which would decrease the renin release which helps drive the hypertension.
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PMID:Factor XII (Hageman factor) is a missing link between stress and hypercoagulability and plays an important role in the pathophysiology of ischemic stroke. 1675 26

Thrombophilia may be defined as an acquired or congenital abnormality of hemostasis predisposing to thrombosis. Because arterial thrombosis is usually linked with classical risk factors such as smoking, hypertension, dyslipidemia, or diabetes, a thrombophilia workup is usually not considered in case of arterial thrombosis. The most accepted inherited hemostatic abnormalities associated with venous thromboembolism are factor V Leiden (FVL) and factor II (FII) G20210A mutations, as well as deficiencies in antithrombin (AT), protein C (PC), and protein S (PS). This review focuses on the link between these abnormalities and arterial thrombosis. Overall, the association between these genetic disorders and the three main arterial complications (myocardial infarction [MI], ischemic stroke [IS], and peripheral arterial disease [PAD]) is modest. Routine screening for these disorders is therefore not warranted in most cases of arterial complications. However, when such an arterial event occurs in a young person, inherited abnormalities of hemostasis seem to play a role, particularly when associated with smoking or oral contraceptive use. These abnormalities also seem to play a role in the risk of premature occlusion after revascularization procedures. Therefore thrombophilia tests may be informative in a very restricted population with arterial events. Anticoagulants rather than antiplatelet therapy may be preferable for these patients, although this remains to be proven.
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PMID:Inherited thrombophilia in arterial disease: a selective review. 1743 3


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