摘要:

A critical review is given of the tests available for the assessment of the action of anticoagulants, such as heparins, oral anticoagulants and direct thrombin inhibitors, in patients under antithrombotic therapy. The principle of action and the performance of the thromboplastm time (PT), the activated partial thromboplastin time (aPTT), the whole blood clotting time, the thrombin time, the ecarin clotting time and the endogenous thrombin potential (ETP) is discussed, as well as the evidence behind the accepted therapeutic ranges. The two most common tests, PT and aPTT, respond in an essentially different way to clinically effective anticoagulation with hepa-rin and with oral anticoagulants. This means that they covar-iate with, but do not themselves represent the essential parameter influenced by anticoagulation. The experimental basis for the widely accepted two times prolongation of the aPTT as an indicator for adequate anticoagulation is shown to be meagre in the case of unfractionated heparin and lacking for the other anticoagulants. Common sources for error in the interpretation of anti-factor Xa- and anti-thrombin activity of heparins are indicated. Extensive experience with new tests like the ecarin clotting time and the ETP is still lacking. On the basis of preliminary data and in view of the importance of the enzymatic action of thrombin in the pathogenesis of thrombosis, the ETP is considered a possible candidate for a common parameter to assess different types of anticoagulants.

ISSN:1424-8832    

DOI:10.1159/000217459

出版商:S. Karger AG    

年代:1997

数据来源: Karger

摘要:

Tissue injury during hip surgery results in the activation of the haemostatic system. The aim of this study was to detect markers of haemostatic activity, i.e. prothrombin fragment 1 and 2 (Fl+2), thrombin-antithrombin (TAT) complexes, fibrin degradation products (FbDP), and soluble fibrin monomers (SF), preoperatively, and on days 1, 7 and 35 in plasma of patients undergoing total hip arthroplasty. The study was part of a mul-ticentre study in which the patients were randomized to receive a subcutanous injection of low molecular weight heparin (LMWH, dalteparin, Fragmin®) once daily for 5 weeks or placebo following a 1-week LMWH treatment (once daily). Bilateral phlebography was performed between days 33 and 35 or before if patients had clinical symptoms of deep vein thrombosis. A lung scan was performed in patients with clinical symptoms of pulmonary embolism. Levels of the markers were significantly increased on day 35 in the patients receiving LMWH for 7 days compared to patients receiving LMWH for 35 days. In patients receiving LMWH for 5 weeks, levels of FbDP and SF were significantly higher during the entire study period, but TAT and Fl+2 were normalized on day 35. The markers were increased two to five times on the 1 st postoperative day in patients with diagnosed venous thromboembo-lism

ISSN:1424-8832    

DOI:10.1159/000217460

出版商:S. Karger AG    

年代:1997

数据来源: Karger

摘要:

Hereditary protein S deficiency is a risk factor for developing recurrent venous thromboembolic disease and is caused by a defect in the protein S 1 (PROSl) gene. Identification of the mutation in the PROSl gene can overcome diagnostic uncertainty in family members with borderline protein S levels. We describe a novel nonisotopic method for molecular diagnosis of protein S deficiency, using fluorescein-labeled amplification and sequencing primers. As a first step, all exons of the PROS 1 gene are selectively amplified, and heteroduplex analysis is performed. As a second step, all exons are analyzed by direct sequencing. Using this method, we have characterized the molecular defect in two Belgian families with hereditary protein S deficiency type I: a frameshift mutation in exon XIV (1881insTC) and a missense mutation caused by a T-to-C transition, resulting in substitution of Leu405 by Pro (L405P).

ISSN:1424-8832    

DOI:10.1159/000217461

出版商:S. Karger AG    

年代:1997

数据来源: Karger

摘要:

Thrombotic potential and hemodynamic changes were assessed in the cerebral microcirculation in normal rats (WKY), non-stroke-prone spontaneously hypertensive rats (SHR) and stroke-prone spontaneously hypertensive rats (SHRSP) at the age of 4, 16 and 32 weeks. Whole blood platelet aggregation revealed that the platelet aggregability in vitro was significantly depressed in SHRSP compared to WKY at 16 and 32 weeks using 2 μg/ml collagen but was similar or higher than WKY at 32 weeks using 20 or 40 μg/ml collagen. Platelet-rich thrombi were induced using a helium-neon (He-Ne) laser technique in vivo. The numbers of laser pulses required to induce an occlu-sive thrombus in arterioles were similar in the three strains at the age of 4 weeks. In contrast, the numbers of laser pulses needed to induce vascular occlusion in SHR (5.5 ± 0.7; n = 4) and SHRSP (4.9 ± 0.3; n = 4) were lower than in WKY (7.4 ± 0.3; n = 5) at the age of 16 weeks. Similar differences were observed at 32 weeks (SHR 5.8 ± 0.2; n = 6; SHRSP 4.3 ± 0.1; n = 4; WKY 7.0 ± 0.2; n = 7). Red blood cell velocities were measured in pial arterioles using a fiber-optic laser Doppler anemometer microscope. Red cell velocities and wall shear rates in SHR and SHRSP were significantly lower than those in WKY (p < 0.05) at the age of 16 weeks and were markedly lower in SHRSP than in either WKY or SHR at the age of 32 weeks. The plasma concentration of nitrite/nitrate determined by the Griess reaction was significantly reduced in SHRSP at 32 weeks compared with 4-week-old rats. These changes could contribute to the enhanced tendency to cerebro-vascular stroke i

ISSN:1424-8832    

DOI:10.1159/000217462

出版商:S. Karger AG    

年代:1997

数据来源: Karger

摘要:

Warfarin-induced skin necrosis is a rare complication of warfarin therapy. It appears between days 1 and 10 of therapy while the patient is receiving warfarin. Warfarin-induced skin necrosis occurring several days after cessation of therapy has not been reported. We report an atypical case of warfarin-induced skin necrosis which occurred 96 h after the last dose of warfarin was given while the prothrombin time was still elevated.

ISSN:1424-8832    

DOI:10.1159/000217463

出版商:S. Karger AG    

年代:1997

数据来源: Karger

摘要:

Hydroxyethyl starch (HES) is often used for volume therapy. Since bleeding complications have been reported repeatedly, a strict dose limitation of a maximum of 1,500 ml 6% solution per day is recommended. However, many indications require higher dosages. Bleeding complications are known to be caused by an acquired von Willebrand syndrome. It has been shown that the accumulation of large molecules and their impairment in the coagulation system can be avoided by using HES preparations with a low in vivo molecular weight. However, the effects of a high-dose therapy have not been studied yet. We have investigated, how a 4-day high-dose therapy, using 3,000 ml 6% HES 70/0.5 on the 1st day and 1,500 ml on days 2-4, affects the coagulation system and hemorheological parameters of acute stroke patients. Thromboplastin time, activated partial thromboplastin time and thrombin time showed no significant changes, except for a slight, clinically irrelevant change due to dilution. The subunits of von Willebrand factor VIII showed no significant change. Hematocrit decreased from 42.3 ± 4.6 to 37.4 ± 3.9% (p < 0.05) after day 1, reaching 35.3 ± 4.2% (p < 0.01) at the end of the therapy, demonstrating a substantial volume effect. Plasmaviscosity and erythrocyte aggregation decreased slightly, however not significantly. Our study shows that even a high-dose therapy with 6% HES 70/0.5 has no influence on the coagulation syst

ISSN:1424-8832    

DOI:10.1159/000217464

出版商:S. Karger AG    

年代:1997

数据来源: Karger