Thrombo-embolism

Streptokinase is administered by intravenous or intra-arterial infusion in the treatment of thrombo-embolic disorders, e g. pulmonary embolism, deep-vein thrombosis and arterial occlusiorrs. It is also used in acute myocardial irtfarclioa... 

Streptokinase is a widely employed thrombolytic agent. It is administered to treat a variety of thrombo-embolic disorders, including ... 

Q67 The use of heporins for the management of thrombo-embolic disease in pregnancy ... 

Higher molecular mass dextrans (partieularly dextran 70, 75 and 110) are used to promote short-term expansion of plasma volume thus preventing/treating shoek due to blood loss. A 6% w/v solution of these dextrans exerts an osmotie pressure similar to that of plasma proteins. Generally, an initial dose of 500 ml 1 litre is administered by i.v. infusion. Dextrans also inhibit the aggregation of red blood eells. Thus, they are often used to prevent/treat post-operative thrombo-embolic disorders (see later in this ehapter) and to improve blood flow. 

Fever is common in, and often a sign of, infection irrespective of its cause. Other diseases, which cause fever, are tumours, non-infectious inflammations, endocrine disorders and thrombo-embolic disease. Drugs can cause fever, e.g. angiotension-II-antagonists, ACE inhibitors and phenytoin. 

Royal College of General Practitioners. Oral contraception and thrombo-embolic disease. J R Coll Gen Pract 1967 13(3) 267-79. 

Ksidcar W, Murray WJO Efficacy and safety of low molecular weight hq>arin (CY 216) in preventing postoperative venous thrombo-embolism A cooperative study. BrJSurg (1985) 72 786-791. 

Endothelin may also have a role in ischaemic stroke. Endothelin, released after ischaemia caused by thrombo-embolic occlusion of a cerebral vessel, could propagate further infarction by constricting the collateral circulation. Much less information is available on endothelin in ischaemic stroke but endothelin levels are raised in animal models of focal ischaemia [183] and in ischaemic stroke patients [184]. 

Lindoff C, Rybo G, Astedt B. Treatment with tranexamic acid during pregnancy, and the risk of thrombo-embolic complications. Thromb Haemost 1993 70(2) 238-40. 

M. M. Hartman, Thrombo-embolic Phenomena in Severe Asthma. Use of Heparin for Prevention and Treatment in Patients Receiving ACTH or Glucosteroids, California Med., 98, 27 (1963). 

However, estrogen has been demonstrated to be associated with the increased incidence of breast and endometrial cancer after prolonged treatment. In addition, during HRT, venous thrombo-embolic complications are encountered more frequently than in women not undergoing HRT [71]. Therefore, there is a growing interest in using isoflavones as a potential alternative to the estrogens in hormone replacement therapy. 

In spite of the desirable characteristics of the biomaterials used in the heart valve prostheses, problems with thrombo-embolic complications are significant with implanted valves and patients with mechanical valves are under long-term anticoagulant therapy. The mechanical stresses induced by the flow of blood across the valve prostheses have been finked to the lysis and activation of fornied elements of blood (red blood cells, white blood cells, and platelets) resulting in the deposition of thrombi in regions with... 

Cheon and Chandran, 1994]. Further improvements in the design of the valves based on the closing dynamics as well as improvements in material may result in minimizing thrombo-embolic comphcations with implanted mechanical valves. 

Thrombo-embolic complications, in mechanical heart valves, 44-5... 

Thrombo-embolism is a well known complication in patients with prosthetic heart valves. The pathogenesis of thrombo-embolic incidents is unclear but it seems that platelets play a significant role, due to the interaction between these cells and the artificial surfaces of the prosthetic valve. In an attempt to detect possible metabolic abnormalities, heat production rate was measured in platelets from patients with prosthetic cardiac valves [84]. Significantly decreased calorimetric values were observed, indicating that the metabolic activity of platelets in these patients is abnormally low (see Table 16). 

These results are in agreement with the observations of other investigators who had previously found decreased platelet ADP and ATP as well as shortened platelet survival, that correlated with thrombo-embolic manifestations in patients with prosthetic heart valves. No conclusive explanation can be offered for the observation of decreased heat production rate in the platelets of patients with prosthetic heart valves. Previous investigators have advanced the hypothesis that mechanical, chemical or immunological factors may cause alterations of blood cell function by interaction of the cells with the prosthetic valves. It is interesting to note that in the calorimetric study, the two patients who had double prosthetic valves were found to have P values below the mean value of the whole patient group. Moreover, the only patient who exibited thrombo-embolic manifestations, had the lowest value of platelet heat production rate. 

These studies seem to indicate that microcalorimetry is a suitable method for the quantitative measurement of overall metabolism in platelets from patients with prosthetic heart valves. It might be of help for identification of patients with high risk to develop thrombo-embolic complications after replacement of heart valves. 

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