Haemostasis
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Case Reports
Fibrinogen kaiserslautern III: a new case of congenital dysfibrinogenemia with aalpha 16 arg-->cys substitution.
An abnormal fibrinogen was identified in a man with suspicious prolonged prothrombin time and a mild bleeding tendency. Coagulation studies showed marked prolonged thrombin and reptilase clotting times and a discrepancy between functional fibrinogen test and fibrinogen antigen. ⋯ This mutation was found also in his 2 children. Both had a mild bleeding tendency too.
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A reliable prothrombin time (PT) testing and a careful drug dosage can prevent thrombotic or bleeding complications of the oral anticoagulant therapy. The international normalised ratio (INR) as PT standardisation introduced an analytical variation that increases with higher PT measures and higher international sensitivity index (ISI) values. Our study was conducted to investigate the INR accuracy through the mathematical derivative application to reduce the analytical component of the INR uncertainty. ⋯ The data expressed as PT ratios revealed a lower systematic error propagation suggesting that a linear system is more accurate. According to the calculation formula of INR, analytical variability increases with the PT measurements, then with the intensity of anticoagulation. Mathematical derivative suggests that the INR uncertainty due to the ISI can be reduced using a thromboplastin reagent with a low ISI or with ISI close to 1.
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To investigate how thrombin time, activated partial thromboplastin time (APTT) and prothrombin time are influenced by fibrinogen degradation products (FDP), different concentrations (0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.8 and 1.0 mg/ml) of the purified FDP X, Y, D and E were added to the plasma of healthy dogs. If fragment Y was added to the plasma a considerable inhibitory effect could be demonstrated for all three test systems. A significant prolongation (p < 0.05) was found for concentrations of > or =0.1 mg/ml (thrombin time, APTT) and > or =0.2 mg/ml (prothrombin time). ⋯ As regards the other fragments, a comparable inhibitory effect could only be shown for fragment X added to the thrombin time test system. This effect can most probably be explained by the competition of the FDP X and fibrinogen for the fibrinogen binding sites of thrombin, rather than by a fibrin polymerization disorder. The results demonstrate that for plasma with normal fibrinogen concentration the group tests are only prolonged beyond the reference range at FDP concentrations very rarely found in spontaneous hyperfibrinolysis.
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Review Comparative Study
Aspirin in the treatment and prevention of cardiovascular disease.
Randomized trials of aspirin have been conducted in three main populations: patients with evolving acute myocardial infarction (MI), patients with a history of cardiovascular disease and apparently healthy subjects. Initiating aspirin therapy within 24 h after the onset of symptoms of an acute MI results in conclusive reductions in the risk of nonfatal reinfarction, nonfatal stroke and total cardiovascular death. ⋯ Randomized data from studies in women and other populations are lacking. Until more data are available, the decision to use aspirin in primary prevention should be based on the clinical judgment of the physician and it should be used as an adjunct in the management of other cardiovascular disease risk factors.
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Review Comparative Study
Risk assessment and prophylaxis of venous thromboembolism in acutely and/or critically ill patients.
Both undetected and clinically evident venous thrombosis and venous thromboembolism (VTE) can seriously impact the prognosis of acutely and/or critically ill patients. Pulmonary embolism (PE) is harder to diagnose in the acutely and/or critically ill, many of whom also have developed respiratory failure for other reasons. Deep vein thrombosis (DVT) of the upper and lower extremities can subsequently complicate insertion of central venous catheters, leading to PE, sepsis and septic shock. ⋯ While LMWH appears superior to UFH in acute stroke patients to prevent venographically-proven lower-extremity DVT, whether it provides a superior long-term outcome after acute stroke is uncertain. One study found that a high dosage of the LMWH dalteparin was more effective than placebo in preventing left ventricular thrombi after acute myocardial infarction, but there was a significant safety cost. Current questions surrounding prophylaxis of VTE and the use of LMWH in acutely and/or critically ill patients include whether monitoring levels and dosage adjustment in some of these patients would improve outcome, and whether the diagnosis of VTE can be improved so that treatment can be instituted when prophylaxis has failed.