A clinical and family study of hereditary proconvertin (factor VII) deficiency

Hall, Charles A.; Rapaport, Samuel I.; Ames, Sara Beth; DeGroot, Jean A.; Allen, Edward D.; Ralston, Marc A.

doi:10.1016/0002-9343(64)90003-8

Cited by 82 publications

(39 citation statements)

References 21 publications

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“…As mentioned earlier, venous thromboembolism has been reported in patients with hereditary factor VII deficiency (3,4). Adding purified factor VII to a plasma level of 5% generated maximal prothrombinase activity when the coagulation reactions of hereditary factor VII-deficient plasma were initiated in vitro with dilute TF (6).…”

Section: Discussionmentioning

confidence: 74%

“…Reports ofvenous thrombo-embolism in patients with hereditary factor VII deficiency (3,4) also raised uncertainty as to the importance ofdepressed factor VII activity for warfarin's antithrombotic efficacy. Recently, Furie et al (5) reported that the plasma native prothrombin antigen level correlated closely with the presence of bleeding or thromboembolic complications in patients given warfarin.…”

Section: Introductionmentioning

confidence: 99%

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Mechanism of the anticoagulant effect of warfarin as evaluated in rabbits by selective depression of individual procoagulant vitamin K-dependent clotting factors.

Zivelin¹,

Rao²,

Rapaport³

1993

J. Clin. Invest.

129

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We have evaluated the contribution of depression of individual procoagulant vitamin K-dependent clotting factors to the ability of warfarin to protect rabbits against tissue factor-induced coagulation. Mean activities of individual procoagulant factors were determined, in assays with rabbit substrates, for a group of rabbits achieving a protective degree of anticoagulation with warfarin. Values were: factor VII, 12%; factor IX, 7%; factor X, 14%, and prothrombin, 13%. The effect upon tissue factor-induced coagulation of selective immunodepletion of each factor to a comparable level was then evaluated. Immunodepletion of plasma factor X or prothrombin, but not of factor VII or factor IX, protected otherwise normal rabbits against tissue factorinduced coagulation. Next, we determined the effect upon the protection in warfarin-treated rabbits of selectively restoring factor X or prothrombin before infusing tissue factor. When either factor was selectively restored, warfarin's protective effect was abolished. Moreover, selective restoration of prothrombin sensitized warfarin-treated rabbits to coagulation more severe than observed in nontreated control rabbits. One may extrapolate from these data that depression of both factor X and prothrombin are required for warfarin's clinical antithrombotic efficacy and that depression of plasma prothrombin is particularly important. (J. Clin. Invest. 1993. 92:2131-2140

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Section: Discussionmentioning

confidence: 74%

Section: Introductionmentioning

confidence: 99%

Mechanism of the anticoagulant effect of warfarin as evaluated in rabbits by selective depression of individual procoagulant vitamin K-dependent clotting factors.

Zivelin¹,

Rao²,

Rapaport³

1993

J. Clin. Invest.

129

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“…Typically, even a very low level of functional VII will prevent spontaneous bleeding. In fact, a level of only 10-20% of normal is considered adequate to assure normal hemostasis at the time of major surgery [30,31]. The second explanation for the increased incidence of hemorrhage in the first few months of warfarin therapy is that patients with a high risk for hemorrhage (i.e., those with a subclinical lesion or hemorrhagic diathesis) will bleed during the initial period of anticoagulation.…”

Section: Discussionmentioning

confidence: 99%

Comparison of plasma prothrombin and factor VII and urine prothrombin F1 concentrations in patients on long‐term warfarin therapy and those in the initial phase

et al. 1998

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Control of warfarin anticoagulation during the initial phase of therapy is difficult and empirically based. Plasma and urine samples were obtained from normal controls, patients under stable anticoagulation, and patients in the initial phase of anticoagulation. Total plasma prothrombin, des-carboxy (non-adsorbable with barium chloride) prothrombin, and native (total minus non-adsorbable) prothrombin were quantitated using Echis carinatus venom activation. Functional plasma factor VII (VII) was measured using a one-stage clotting assay. Total and des-carboxy urine prothrombin F1 (F1) were measured by ELISA. All urine F1 in normals and both anticoagulated groups was adsorbed by barium chloride. Plasma des-carboxy prothrombin concentration was similar for the two anticoagulated groups and did not correlate with 1/INR. Native prothrombin correlated with 1/INR in both the stable (r = 0.76) and initial phase (r = 0.74) groups. For any given INR, the subjects on stable anticoagulation had lower native prothrombin concentrations than the initial phase patients. Functional factor VII concentration also correlated significantly with 1/INR in both the stable (r = 0.64) and initial phase (r = 0.76) patients. Unlike native prothrombin, VII concentrations did not vary between the two cohorts for any given INR. Previous studies indicate that native prothrombin is a superior predictor of both hemorrhagic and thromboembolic complications during warfarin therapy. Our findings indicate that VII, and not prothrombin, may be the predominant factor monitored by the INR. This further supports the need to reevaluate the usefulness of the INR in the monitoring of warfarin therapy during the initial phase. Am.

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“…4 When the level of zymogen Factor VII is low, or the amount of Factor VII to Factor VIla decreased, one would expect the dampening effect of Factor VII to be diminished. It is tempting to speculate that the loss of this inhibitory effect of zymogen Factor VII might contribute to the thrombotic complications associated with congenital Factor VII deficiency (48)(49)(50), loading dose coumarin therapy (51,52), and infusion of prothrombin complex concentrates, which may contain high levels of activated Factor VII (46,(53)(54)(55)(56)(57)(58)(59)(60)(61)(62).…”

Section: Methodsmentioning

confidence: 99%