Clinical Use of Low Molecular Weight Heparins and Heparinoids

Levine, Mark; Hirsh, Jack

doi:10.1055/s-2007-1002764

Cited by 25 publications

(12 citation statements)

References 29 publications

(94 reference statements)

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“…For low-molecular-mass (LMM) especially, the plasma chromogenic antifactor Xa (AXa) assays are the most common methods [5], Some studies report that antithrombotic activ ity is not correlated to the AXa activity of glycosaminoglycans [10,11], A few authors have found, on the contrary, a correlation between patients' AXa plasma levels and the anti thrombotic effect recorded after treatment with heparin or LMM heparins [12][13][14][15][16], The aim of this study was to investigate a possible correlation between protection against experimental venous thrombosis of three heparins of different molecular mass and plasma AXa levels, assayed at the mo ment of thrombosis induction.…”

Section: Many Attempts Have Been Made To Establish the Therapeutic Ramentioning

confidence: 99%

Relationship between Plasma Antifactor Xa Activity and the Antithrombotic Activity of Heparins of Different Molecular Mass

Bianchini¹,

Bergonzini²,

Parma³

et al. 1995

Pathophysiol Haemos Thromb

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The relationship between the inhibition of venous thrombosis and antifactor Xa (AXa) plasma levels, measured as ex vivo AXa activity at the moment of experimental thrombosis induction, was evaluated in rats treated by different administration routes with different doses of heparins of various molecular masses: unfractionated heparin (UH, 13 kDa), low-molecular-mass heparin (LMM-H, 5kD) and oligo-heparin (OL-H, 2 kD). The AXa activity levels of plasma samples were measured by an amidolytic method and expressed in AXa U/ ml. The antithrombotic effect was determined by a vena cava ligature model and expressed as the percent inhibition of thrombus weight. A correlation between the two parameters was determined, regardless of the administration route used. Every heparin requires different AXa plasma levels to develop the same antithrombotic activity: the plasma concentration inducing a 50% protection was 0.09,0.12 and 0.15 AXa U/ml, for UH, LMM-H and OL-H, respectively. Oligo-H has a significant antithrombotic activity when delivered by the intraileal route and the time course pharmacodynamics showed two phases for the parameters considered: in the second phase, a dissociation between AXa plasma level and antithrombotic effect was observed.

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Section: Many Attempts Have Been Made To Establish the Therapeutic Ramentioning

confidence: 99%

Relationship between Plasma Antifactor Xa Activity and the Antithrombotic Activity of Heparins of Different Molecular Mass

Bianchini¹,

Bergonzini²,

Parma³

et al. 1995

Pathophysiol Haemos Thromb

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“…43 The rate of hemorrhagic complications has been highly variable among the different studies, depending on the type of LMWH preparation used and its dose. 22 Higher doses were associated with an increased risk of bleeding, and a relationship between "ex vivo" anti-Factor Xa levels and hemorrhage has been indicated. 19 ' 31 ' 35 ' 44 ' 45 The risk of bleeding is minimal when the anti-Xa activity does not exceed 0.2 to 0.3 U/ml.…”

Section: Tolerance To Low Molecular Weight Heparinsmentioning

confidence: 99%

“…19 ' 31 ' 35 ' 44 ' 45 The risk of bleeding is minimal when the anti-Xa activity does not exceed 0.2 to 0.3 U/ml. 21,22,45 In some of the studies carried out in general surgery with Fraxiparin, Kabi 2165, and the Sandoz heparin fraction, there was an increased bleeding tendency among treated patients when compared with control groups (Table 1). 24,29,30,33 Most of these hemorrhagic occurrences were considered minor.…”

Section: Tolerance To Low Molecular Weight Heparinsmentioning

confidence: 99%

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Low Molecular Weight Heparins and External Pneumatic Compression as Options for Venous Thromboembolism Prophylaxis: A Surgeon's Perspective

Caprini¹,

Arcelus²,

Traverso³

et al. 1991

Semin Thromb Hemost

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“…These considerations presup pose that LMW heparins achieve prophylac tic efficacy solely by their action within the fluid compartment of blood and that the interactions of LMW heparins with the ves sel wall do not contribute to their overall effectiveness. Some reports suggest that the anti-factor Xa activities of LMW heparins in ex vivo plasmas of patients are predictive of both efficacy and potential haemorrhagic complications [27,28,[52][53][54], It is my view, however, that current anti factor Xa assays ought to be considered as the best surrogate tests for the mass of LMW heparins in patients' plasmas. They do not necessarily reflect the overall catalytic con centrations of LMW heparins in plasma.…”

Section: Discussionmentioning

confidence: 99%

In vitro and ex vivo Activities of CY216: Comparison with Other Low Molecular Weight Heparins

Ofosu

1990

Pathophysiol Haemos Thromb

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Low molecular weight (LMW) heparins achieve their anticoagulant effects by inhibiting prothrombin activation, catalyzing endogenous thrombin inhibition, and binding thrombin. The extent to which each of the three actions of LMW heparins contributes to the antithrombotic effectiveness of LMW in man has not been defined. Several studies have reported that ex vivo anti-factor Xa activities of LMW heparins correlate with efficacy and potential haemorrhagic complications. However, critical review of the data suggests that anti-factor Xa assays are basically surrogate tests for the mass of LMW heparins in patients’ plasmas rather than reliable estimates of total catalytic concentrations of LMW heparins. Antithrombotic effectiveness of LMW heparins probably reflects their ability to inhibit coagulation in vivo. If the last concept proves correct, then results of tests which directly assess the extents to which LMW heparins have suppressed in vivo coagulation may provide more reliable markers for their antithrombotic effectiveness or lack thereof.

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Clinical Use of Low Molecular Weight Heparins and Heparinoids

Cited by 25 publications

References 29 publications

Relationship between Plasma Antifactor Xa Activity and the Antithrombotic Activity of Heparins of Different Molecular Mass

Relationship between Plasma Antifactor Xa Activity and the Antithrombotic Activity of Heparins of Different Molecular Mass

Low Molecular Weight Heparins and External Pneumatic Compression as Options for Venous Thromboembolism Prophylaxis: A Surgeon's Perspective

In vitro and ex vivo Activities of CY216: Comparison with Other Low Molecular Weight Heparins

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