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

It is suggested that the early failure of bypass grafts in patients with clinical evidence of venous hypertension is a result of increased resistance caused by venous obstruction. The importance of using autogenous vein grafts in such cases is emphasized. One should accept the possibility that arterial reconstruction may result in a less successful outcome in patients with chronic venous disease.
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PMID:Chronic venosus obstruction as a factor in the early failure of bypass grafts in the leg. 644 57

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

Air-plethysmography has been used in order to measure resting arterial inflow in 25 normal limbs and 126 limbs with various grades of venous disease. Twenty five limbs had venous ulcers. Resting arterial inflow was 60-95 ml/min in normal limbs (95% range), 60-110 ml/min in 45 limbs with uncomplicated varicose veins, 65-162 ml/min in limbs with swelling and/or lipodermatosclerosis/pigmentation and 100-235 ml/min in limbs with venous ulceration. There was an increase in the incidence of ulceration with increasing values of arterial inflow. The abnormal increase in resting arterial inflow is considered to reflect the damage in the microcirculation produced by chronic venous hypertension. Therapy should aim to treat or prevent this microangiopathy.
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PMID:The hemodynamic effect of venous hypertension in the microcirculation of the lower limb. 759 56

Before and after venous stasis and upon recovery blood samples were drawn from the saphenous vein in 10 patients with varicose veins (Group 1), in 10 with venous hypertension (Group 2) and in 10 healthy controls. The total leucocyte count, the leucocyte filterability rate (LFR), superoxide dismutase blood concentrations (SOD) and the production of superoxide anions from granulocytes were determined. After stasis, the total leucocyte count increased significantly (p < 0.01) in both groups of patients and the LFR was significantly (p < 0.01) impaired. SOD blood concentrations fell significantly (p < 0.01) and oxygen free radical production dropped significantly (p < 0.01) in both groups. Upon recovery, all parameters returned to normal in Group 1 but significant differences remained in Group 2. No significant modification was observed at any stage of the study in the control group. These results suggest that impairments in leucocyte rheology and granulocyte production of oxygen free radicals cause capillary plugging and possibly damage to microcirculatory vessel walls in venous disease.
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PMID:Leucocyte activity in chronic venous insufficiency. 779 Jul 51

The aim of this study was to evaluate the effect of hydroxyethylrutosides on capillary filtration in subjects with mild to moderate venous incompetence--superficial varicose veins and/or deep venous disease and ankle oedema--using the vacuum suction chamber (VSC) device applied to the internal perimalleolar region and the wheal vanishing (WV) time. Subjects entered in to the study were randomised to receive either hydroxyethylrutosides (1 g twice daily for 4 weeks) or placebo for four weeks. The two groups entering and completing the study were comparable. Microcirculatory parameters (laser-Doppler resting flux, the venoarteriolar response, transcutaneous PO2 and PCO2) remained constant during the four week study in both groups. The WV time, which was comparable in the two groups at the beginning of the study decreased significantly [from a median 55 min (interquartile 955 min), to a median 45 minutes (interquartile 65-40 min) in the treated group, p < 0.01]. No change was observed in the WV time in the placebo group. Subjective symptoms measured with an analogue scale improved following treatment with hydroxyethylrutosides [foot oedema (p < 0.005), ankle oedema (p < 0.001), and paraesthesia (p < 0.01)]; only night cramps were reported less in patients receiving the placebo (p < 0.05). In conclusion, the WV time can be used to assess the beneficial effect of therapy on capillary filtration in subjects with mild-moderate venous hypertension, even after a short period of treatment, and before other microcirculatory parameters change. Furthermore, the changes observed in WV time correlate well with an improvement in patients symptoms.
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PMID:The effect of hydroxyethylrutosides on capillary filtration in moderate venous hypertension: a double blind study. 782 3

The acute variation in capillary filtration [CF] was evaluated with strain-gauge plethysmography in patients with severe venous hypertension due to deep venous disease. Two groups were selected and randomly treated with a single oral dose or TTFCA (60 mg or 120 mg). CF was assessed again after 5 and 10 hours. Eleven patients were randomised in the 60 mg group and 9 in the 120 mg group. Also 5 normal subjects were studied with the same procedure to act as controls. No variations in CF were observed in normal limbs. In both groups of patients there was a significant decrease in CF after 5 and 10 hours. The percent decrease in CF after 10 hours was higher in the high dose group. These results indicate that TTFCA is acutely effective in reducing CF and oedema in subjects with venous hypertensive microangiopathy. The effects of TTFCA on CF appear to be dose related.
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PMID:Acute effects of TTFCA on capillary filtration in severe venous hypertension. 783 Oct 65

Cerebral vein thromboses constitute a major part of cerebral venous disease. They can occur at any age, generally in young subjects, and are due to a variety of causes, although no aetiology can be detected in one quarter of cases. They generally occur in the superior sagittal sinus and transverse sinuses, while involvement of the deep veins and posterior fossa veins is much less common. The symptoms consist of varying degrees of signs of intracranial hypertension (ICH) and focal and/or epileptic signs. The onset may be sudden, subacute or chronic, simulating a cerebral vascular accident, an abscess, encephalitis, a tumour or benign ICH. Radiological investigations, especially MRI and angiography, are the key to the diagnosis. A fatal outcome is observed in 10% of non-infectious forms. The benefit of heparin therapy, although controversial for a long time, has now been clearly established.
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PMID:[Cerebral venous thromboses. Clinical diagnosis]. 817 75

Although less frequent than that of the lower limbs, venous thrombosis of the upper limbs may cause pulmonary embolism. This embolism is usually moderate and facilitated by the delay or absence of anticoagulant treatment. We report the case of a young man who had multiple and recurrent embolism consecutive to thrombosis of the axillary and subclavian veins and who rapidly developed pulmonary arterial hypertension on previously healthy lungs. There was no venous disease of the lower limb. After a more than 2 years' period, the pulmonary arterial hypertension is still moderate, but the patient remains under long-term antivitamin K therapy, this being the only available treatment capable of preventing a deterioration that would result in post-embolic cor pulmonale and ultimately require lung transplantation.
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PMID:[Unusual complication of venous thrombosis of the upper limb: pulmonary hypertension]. 829 44

Hyperhomocyst(e)mia (Hcy) negatively influences vascular endothelium and coagulation factors. Association of Hcy with premature arteriosclerosis (rather than atherosclerosis), stroke, myocardial infarction and peripheral arterial and venous disease was proved in clinical and epidemiological studies, even as the association with conventional risk factors like age, male sex, smoking, hypertension and hypercholesterolemia. Vitamin substitution of folates, vitamin B6 and B12 decreases Hcy blood levels, however definite evidence is still lacking, whether it results in lower incidence and mortality from cardiovascular diseases. Therefore clinical and epidemiological studies are necessary. Before the grant-application we proved in a pilot study significantly higher Hcy levels in 97 patients with manifest ischaemic heart disease than in 37 controls.
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PMID:[Homocysteine, a less well-known risk factor in cardiac and vascular diseases]. 870 81

The authors studied 200 consecutive outpatients with symptoms due to venous disease of the lower limbs. All the patients underwent anamnestic, clinical and instrumental evaluation (c.w. Doppler velocimetry and strain-gauge plethysmography). The results of this study showed that some anamnestic and clinical data are significantly related to venous disease detected by instrumental techniques. The superficial and deep vein hypertension were, instead, correlated to oral contraceptive use.
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PMID:Clinical-anamnestic and instrumental data in outpatients suffering from venous disease. 870 36


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