Anticoagulation thromboembolic complications

Warfarin has been the primary oral anticoagulant used in the United States for the past 60 years. Warfarin is the anticoagulant of choice when long-term or extended anticoagulation is required. Warfarin is FDA-approved for the prevention and treatment of VTE, as well as the prevention of thromboembolic complications in patients with myocardial infarction, atrial fibrillation, and heart valve replacement. While very effective, warfarin has a narrow therapeutic index, requiring frequent dose adjustments and careful patient monitoring.15,29... 

Thromboembolic complications Adjunct to coumarin anticoagulants in the prevention of postoperative thromboembolic complications of cardiac valve replacement. 

When neuraxial anesthesia (epidural/spinal anesthesia) or spinal puncture is employed, patients who are anticoagulated or scheduled to be anticoagulated with low molecular weight heparins (LMWHs) or heparinoids for prevention of thromboembolic complications are at risk of developing an epidural or spinal hematoma, which can result in long-term or permanent paralysis. 

Thrombocytopenia, heparin-induced For anticoagulation in patients with heparin-induced thrombocytopenia (HIT) and associated thromboembolic disease in order to prevent further thromboembolic complications. 

E. Therapeutic response Thrombin-dependent tests show dose dependency [aPTT rise proportionally to dose of Refludan]. The key criteria of efficacy in two pivotal clinical trials from a laboratory standpoint were platelet recovery and effective anticoagulation. Seven days after the start of treatment with Refludan in patients with HIT, the cumulative risk of death, limb amputation, or new thromboembolic complication was substantially lower than in a historical control group. 

Anticoagulants are sometimes used in the overall treatment of PVE even though there are risks of intracerebral hemorrhage or hemorrhagic infarction. Countering this risk, however, is the risk of major thromboembolic complications involving the central nervous system that may occur in die absence of continued anticoagulant therapy. 

Rheumatic mitral valve disease is associated with thromboembolic complications at reported rates of 1.5 to 4.7% per year the incidence in patients with mitral stenosis is approximately 1.5 to 2 times that in patients with mitral regurgitation. The presence of atrial fibrillation is the single most important risk factor for thromboembolism in valvular disease, increasing the incidence of thromboembolism in both mitral stenosis and regurgitation four- to sevenfold. In current practice, patients with nonrheumatic atrial fibrillation at low risk for thromboembolism based on clinical characteristics frequently are treated with aspirin. Warfarin therapy is considered in higher-risk patients, especially those with previous thromboembolism and in whom anticoagulation is not contraindicated due to preexisting conditions. 

The anticoagulant warfarin is increasingly used to prevent thromboembolic complications in patients with atrial fibrillation. The drug is administered as racemate, and bio-inactivation of the active S-enantiomer is accomplished by CYP2C9. Relatively common variants in CYP2C9 that reduce its function have been described, and homozygotes for reduction of function alleles... 

The most widely prescribed anticoagulant in North American is warfarin sodium (Coumadin). It was discovered serendipitously in the early 1940s at the University of Wisconsin after hemorrhagic deaths occurred in cattle eating spoiled sweet clover. Warfarin is approved by the FDA for the prevention and treatment of VTE as well as for the prevention of thromboembolic complications associated with atrial fibrillation, heart valve replacement, and myocardial infarction. Because of its narrow therapeutic index, predisposition to drug and food interactions, and propensity to cause hemorrhage, warfarin requires... 

Dipyridamole is indicated as an adjunct to therapy with cou-marin anticoagulant in the prevention of postoperative thromboembolic complications of cardiac valve replacement as an alternative to exercise in thaUium myocardial perfusion imaging for the evaluation of coronary artery disease in patients who are unable to exercise and in long-term therapy for angina pectoris. Dipyridamole inhibits platelet adhesion and is a coronary vasodilator. Inappropriate use of dipyridamole has caused MI, ventricular fibrillation, tachycardia, bronchospasm, and transient cerebral ischania (see also Figures 14 and 92). 

Cause minimum trauma to blood elements and the endothelial tissue of the cardiovascular structure surrounding the valve. Show a low probability for thromboembolic complications without the use of anticoagulants. 

Cardiovascular The main adverse effect of prothrombin complex concentrates is a risk of thrombosis, as patients taking oral anticoagulants have prothrombotic susceptibility factors [31, 33 ]. Reported thromboembolic complications include ischemic stroke, venous thromboembolism (venous thrombosis or pulmonary embolism), myocardial infarction, and disseminated intravascular coagulation [32 ]. 

One might add that this is by no means the first pointer to an interaction of hormonal contraceptives with anticoagulants [SEDA-5, 371]. Oral contraceptives have effects on clotting factors and the thromboembolic complications associated with contraceptives are of course very well known. 

Adequate orders for discontinuation, bridging or timing of anticoagulants must be written to avoid interference with the planned surgery and LRA, but also in order to avoid thromboembolic complications [8]. In patients with recently stented coronaries, mechanical valves or chronic atrial fibrillation, a cardiology consult should be obtained. 

The comprehensive review by Douglas provides a recent discussion of the clinically useful anticoagulants. Recent studies have shown heparin to be clearly effective in clinical states In which disseminated Intravascular coagulation was Indicated to be a pathologic factor.75 xhe most commonly employed oral anticoagulants are of the coumarin type such as warfarin and nicoumalone. The oral anticoagulants appear to be of value in the prevention of thromboembolic complications after myocardial infarction.9 76 However, anticoagulation therapy has been found to have no effect on death-rate in these patients.77 Warfarin has been shown to be effective in the prevention of postoperative venous thrombosis. 

In a worldwide survey of AF ablation, major complications were reported in 6% of patients, including cardiac tamponade in 1.2%, stroke in 0.28% and transient ischemic attacks in 0.66% of left sided procedures (164). Periprocedural mortality was reported in 0.05%, Most thromboembolic strokes occur within two weeks of the ablation procedure (165). To reduce the risk of stroke, anticoagulation is often instituted prior to ablation, particularly in patients with CHADS-II risk factors (congestive heart failure or left ventricular dysfunction, hypertension,... 

Venous thromboembolism (VTE) is a complicating condition responsible for high morbidity and mortality in North America and Europe. This disease commonly is linked to advanced age but has both hereditary and acquired risk factors, such as surgery, any form of trauma, and childbirth, associated with it. It encompasses the conditions of deep vein thrombosis (DVT) and pulmonary embolism. In excess of 60,000 deaths annually are attributed to pulmonary embolism. Preventative therapy consists of the use of two different classes of antithrombotic agents, namely anticoagulants and antiplatelet drugs (1,2). 

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