In vitro effect on heptest® of low molecular weight heparin fractions and preparations with various anti-IIa and anti-Xa activities

Bara, L.; Mardiguian, J; Samama, M

doi:10.1016/0049-3848(90)90075-n

Cited by 35 publications

(15 citation statements)

References 3 publications

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“…113,114 Although another study showed that Heptestmeasured Xa-like activity levels using finger-stick specimens were comparable to those measured with a chromogenic substrate assay using venous blood specimens, 115 a subsequent study from the same investigators showed that Heptest values were 10 -20% larger than those from the chromogenic (i.e., S 222) method. 117 Heptest measurements have also been shown to reflect the anticoagulant tissue pathway factor inhibitor properties of tissue pathway factor inhibitor released by heparin. 117 Heptest measurements have also been shown to reflect the anticoagulant tissue pathway factor inhibitor properties of tissue pathway factor inhibitor released by heparin.…”

Section: Heparin Concentration Assaysmentioning

confidence: 99%

Anticoagulation Monitoring during Cardiac Surgery

et al. 1999

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The literature does not consistently support the importance of anticoagulation monitoring techniques during CPB. This is best reflected by studies that have evaluated the impact of the ACT method on blood loss and transfusion outcomes. Inconsistent findings from studies that evaluated the impact of ACT monitoring may be related to either suboptimal study design (i.e., retrospective, unblinded, nonrandomized) or possibly the diagnostic inprecision of the ACT method used in these studies. There are a small number of well-controlled studies, some of which suggest that bleeding and transfusion outcomes can be improved by refining heparin monitoring techniques, either by sustaining better anticoagulation during CPB or by optimizing protamine doses (i.e., when empiric protocols result in excessive protamine doses). More well-controlled studies are needed to better define the importance of anticoagulation management during CPB.

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Section: Heparin Concentration Assaysmentioning

confidence: 99%

Anticoagulation Monitoring during Cardiac Surgery

et al. 1999

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“…Anti‐Xa activity measurement has been the most widely used method for assessing LMWHs activity and to establish a therapeutic range for a particular LMWH. Even if anti‐Xa and anti‐IIa activities have been well correlated with the dose of subcutaneous (s.c.) injection of LMWH (Hirsh et al , 1987; Frydman et al , 1988; Bara et al , 1987, 1990), experimental studies in animals have not demonstrated a strong correlation between antithrombotic activity and ex vivo anti‐Xa plasma levels (Holmer et al , 1982; Buchanan et al , 1985; Carter et al , 1982; Ockelford et al , 1982a; Fernandez et al , 1986). In contrast, some studies have found a significant statistical relationship between anti‐Xa plasma levels and both thrombotic and haemorrhagic outcomes with different LMWHs (Levine et al , 1989; Koller et al , 1986).…”

mentioning

confidence: 99%

Occurrence of thrombosis and haemorrhage, relationship with anti‐Xa, anti‐IIa activities, and D‐dimer plasma levels in patients receiving a low molecular weight heparin, enoxaparin or tinzaparin, to prevent deep vein thrombosis after hip surgery

1999

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Summary. Studies in experimental animal models and in patients receiving low molecular weight heparin (LMWH) to prevent thromboembolic events after surgery have not demonstrated a clear relationship between anti-Xa and anti-IIa activities in plasma and either bleeding or prevention of thrombosis. The relationship between these clinical outcomes and ex vivo anti-Xa and anti-IIa activities, activated partial thromboplastin time (APTT) and D-dimers were evaluated in 440 patients undergoing total hip replacement and given prophylaxis once daily with a LMWH (tinzaparin or enoxaparin) in a multicentre doubleblind randomized study. 221 patients received 4500 anti-Xa IU of tinzaparin; 219 patients received 40 mg (4000 anti-Xa IU) of enoxaparin. Both regimens were administered subcutaneously once daily. Blood samples for anti-IIa, antiXa, D-dimers levels and APTT were taken at baseline, on day 1, day 5 and on the day of discharge (days 8-14) and clinical assessments were performed daily until day 14. All patients had bilateral venography between days 8 and 14.All coagulation tests were performed in central laboratories. A significant correlation was observed between anti-IIa activity and anti-Xa activity and the dose of each LMWH injected. The anti-Xa activity was significantly higher with enoxaparin and the anti-IIa activity was significantly higher with tinzaparin. No clear relationship between these two activities and the clinical outcomes was observed. This was also true with regards to APTT. Before and after surgery, Ddimers were significantly higher in patients with deep vein thrombosis (DVT) than in those without DVT but had no predictive value. Interestingly, a significant post-operative increase of D-dimers persisted in both groups of patients during the whole observation period, possibly suggesting that a longer duration of prophylactic treatment may be appropriate.

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“…At low concentrations of heparin (<0.3 IU/ml), the HEPTEST clotting times from the plasma of pregnant women exceeded those obtained from non‐pregnant women whereas the reverse applied to intermediate (0.3–0.7 IU/ml) and high (>0.7 IU/ml) ranges of heparin concentrations. Some studies have shown that the HEPTEST detects antithrombin (anti‐IIa) activity as well as anti‐Xa activity, which becomes increasingly important at higher concentrations of heparin ( Bara, Mardiguian & Samama 1990). This crossing over of HEPTEST clotting time curves for the plasma of pregnant and non‐pregnant women at higher heparin concentrations may reflect discrepant anti‐IIa activity between the two groups.…”

Section: Discussionmentioning

confidence: 99%

“…This crossing over of HEPTEST clotting time curves for the plasma of pregnant and non‐pregnant women at higher heparin concentrations may reflect discrepant anti‐IIa activity between the two groups. This discrepancy in anti‐IIa activity may indicate reductions in heparin cofactor II levels in pregnancy or changes in the concentration of naturally occurring glycosaminoglycans such as dermatan sulphate and heparan sulphate, which may be detected by the HEPTEST assay ( Bara, Mardiguian & Samama 1990). However, at low concentrations of heparin, anti‐Xa activity is the dominant contributor to the HEPTEST clotting time and permits the extrapolation of anti‐Xa levels.…”

Section: Discussionmentioning

confidence: 99%

HEPTEST: a suitable method for monitoring heparin during pregnancy

Campbell

Tirvengadum

Pickering

et al. 1999

Clinical &Amp; Laboratory Haematology

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Methods of monitoring heparin in pregnancy are problematic. The aim of this study was to assess the plasma HEPTEST as a rapid and reliable test for heparin monitoring in pregnancy. HEPTEST, activated partial thromboplastin time (APTT) and chromogenic anti-Xa assays were performed on individual heparin-spiked plasma samples from two groups: normal non-pregnant women (n = 6) and normal pregnant women during the third trimester (n = 6). Heparin activity curves were established in plasma from both groups for low (< 0.3 IU/ml), intermediate (0.3-0.7 IU/ml) and high (> 0.7 IU/ml) heparin concentrations and validated by comparison with the anti-Xa chromogenic assay. Both the APTT and HEPTEST demonstrated good correlation with anti-Xa levels across all heparin concentrations in both plasma groups (r range = 0.879-0.945). In comparison with the APTT, the HEPTEST showed better correlation with anti-Xa levels at low concentrations of heparin (r values 0.933 vs. 0.772, respectively). For both the APTT and HEPTEST there were significant differences between the clotting times in pregnant and non-pregnant plasma at a number of heparin concentrations. This data supports the plasma HEPTEST as an acceptable alternative to the chromogenic anti-Xa assay for monitoring heparin thromboprophylaxis in pregnancy.

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In vitro effect on heptest® of low molecular weight heparin fractions and preparations with various anti-IIa and anti-Xa activities

Cited by 35 publications

References 3 publications

Anticoagulation Monitoring during Cardiac Surgery

Anticoagulation Monitoring during Cardiac Surgery

Occurrence of thrombosis and haemorrhage, relationship with anti‐Xa, anti‐IIa activities, and D‐dimer plasma levels in patients receiving a low molecular weight heparin, enoxaparin or tinzaparin, to prevent deep vein thrombosis after hip surgery

HEPTEST: a suitable method for monitoring heparin during pregnancy

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