Heparins thromboembolic events

Low-molecular-weight heparins and heparinoids are not recommended in the treatment of acute ischemic stroke.11 A meta-analysis was performed using data from 10 randomized controlled trials.19 A non-significant decrease in combined death and disability and a non-significant increase in case fatality and hemorrhage were seen. A reduction in venous thromboembolic events was observed in acute stroke patients however, there was also an increase in extracranial bleeding. 

J Heparin-induced thrombocytopenia (HIT) is a serious immune-mediated problem that requires immediate intervention. For patients receiving therapeutic UFH doses, a baseline platelet count should be obtained before therapy is initiated and then every-other-day for 14 days or until therapy is stopped, whichever occurs first. HIT should be suspected if a patient develops a thromboembolic event (e.g., DVT, PE, stroke, myocardial infarction, limb artery occlusion) during or soon after receiving UFH. The platelet... 

Freeze-dried concentrates of plasma containing prothrombin, factors IX and X, and varied amounts of factor VII (Proplex, etc) are commercially available for treating deficiencies of these factors (Table 34-3). Each unit of factor IX per kilogram of body weight raises its activity in plasma 1.5%. Heparin is often added to inhibit coagulation factors activated by the manufacturing process. However, addition of heparin does not eliminate all thromboembolic events. 

Two types of heparin-induced thrombocytopenia have been defined. Type I (mild) occurs within the first few days of heparin administration, while type II (severe), which is less common, is generally seen after a week or more of treatment and is often complicated by the recurrence of thromboembolic events. 

Heparin-induced thrombocytopenia usually occurs with a delayed onset (a week or more) and is often comphcated by paradoxical recurrence of thromboembolic events, leading to life-threatening complications. The general term heparin-induced thrombocjdopenia is as a rule used to designate this phenomenon. 

A phase II study to investigate the efficacy and tolerability of the concurrent use of thalidomide 100 mg daily and darbepoetin-alfa 2.25 micrograms/kg per week subcutaneously in patients with myeiodysplastic syndrome was discontinued because of an unexpectedly high incidence of thromboembolic events. Of the first 7 patients enrolled in the study, two developed deep vein thrombosis and one died of pulmonary embolism. The authors recommended careful monitoring and possibly thromboprophylaxis (heparin or warfarin) in patients with myeiodysplastic syndrome given both thalidomide and epoetin. ... 

Anabolic androgenic steroids have been reported to have anticoagulant and profibrinolytic effects in people with protein C deficiency. However, despite these supposed antithrombotic effects, a 19-year-old male athlete with protein C deficiency developed proximal deep venous thrombosis and pulmonary embolism while abusing anabolic androgenic steroids and had repeated venous thromboembolic events during treatment with low-molecular-weight heparin [36 ]. 

Venous thromboembolism is the most common presentation of HIT, although arterial events (e.g., myocardial infarction and stroke) can occur. HIT should be suspected if a patient develops a DVT or PE while or soon after receiving unfractionated heparin. 

As mentioned earlier, the presence of antiphospholipid antibodies may result in several clinical manifestations, including thrombosis. There is no agreement on prophylaxis of patients with antiphospholipid antibodies without a history of thromboembolism. In such patients, low-dose aspirin (100-325 mg/day) may be used prophylactically, although efficacy has not been established. Patients with an acute thrombotic event should receive standard treatment with anticoagulants (e.g., heparin). Follow-up treatment with warfarin to prevent recurrence may require an international normahzed ratio (INR) of 3 or greater in patients with antiphosphohpid syndrome. However, currently, there is no consensus on the intensity of anticoagulation or duration of secondary prophylaxis, but since recurrence is common, patients usually are treated with oral anticoagulants indefinitely. ... 

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