OBJECTIVE

Prospective studies have reported a positive association of coagulation factors with risk of coronary heart disease (CHD). It is unclear whether these coagulation factors interact.

RESULTS

Using a prospective case-cohort design, we analyzed by Cox proportional hazard regression interactions between soluble thrombomodulin (sTM) and fibrinogen, factor VIII (FVIII), FVII, or plasminogen activator inhibitor-1 (PAI-1) in 410 CHD cases and 721 non-cases from the Atherosclerosis Risk in Communities (ARIC). There was a significant interaction between sTM and fibrinogen (p=0.027). We next assessed risk ratios (RR) by combined tertile analysis. Combined analysis revealed that being in the upper sTM tertile counteracted the CHD risk imposed by higher fibrinogen whereas being in the lower sTM tertile amplified the CHD risk of higher fibrinogen. sTM and fibrinogen mutually influenced CHD incidence in a concentration-dependent manner. When analyzed as single factors by tertiles, FVIII, FVII and PAI-1 were not associated with CHD. However, when analyzed together with sTM, FVIII and PAI-1 were both positively associated with CHD for those in the lower sTM tertile.

CONCLUSIONS

There is a complex interaction between sTM and prothrombotic coagulation factors. Combined analysis improves CHD risk assessment.

Since the first report by Trousseau in 1865, several experimental and clinical studies have established that activation of coagulation is common in cancer. However, the biochemical basis of the activation of coagulation in cancer patients is still not completely understood. The current most accepted opinion is that initiation of coagulation in malignancy is driven primarily by activation of the extrinsic (tissue factor-dependent) pathway. In order to further prove that such a pathogenetic mechanism is actually involved in cancer patients, we correlated the plasma levels of activated factor VIIa (FVIIa), which represent a very small fraction of plasma FVII, with some well-established markers of systemic thrombin generation. Circulating FVIIa was measured using a prothrombin time-based assay that employs a truncated form of human recombinant tissue factor, while plasma levels of the thrombin-antithrombin complex, the prothrombin fragments 1 + 2 and D-dimer were determined by commercially available ELISA kits. The study was carried out in 37 patients with different types of cancer and 20 healthy controls. Plasma levels of FVIIa were significantly increased while those of FVII antigen (FVIIag) were decreased in cancer patients compared with controls. Furthermore, the FVIIa/ VIIag ratio was more than two-fold higher in cancer patients than in controls. In addition, an excess of thrombin generation was observed in cancer patients. Interestingly, a positive correlation between the FVIIa/VIIag ratio and the plasma levels of either D-dimer (Spearman's r = 0.325; P = 0.027) or prothrombin fragments 1 + 2 (r = 0.309; P = 0.034) was observed in cancer patients. In conclusion, our study further supports the hypothesis that the tissue factor/VIIa complex is the main determinant of coagulation activation in cancer patients. Large clinical studies will be necessary to determine whether FVIIa and the FVIIa/VIIag ratio are useful prognostic factors of thromboembolic events in cancer patients.

Some observational studies have found a difference in the risk of nonfatal venous thromboembolism (VTE) with low-dose, oral contraceptives (OCs) containing desogestrel (DSG) or gestodene (GSD) and those containing levonorgestrel (LNG). However, this does not agree with current pathophysiological concepts. This review compares all 17 comparative studies on the hemostatic effects of DSG/GSD- and LNG- or norgestimate (NGM)-containing OCs, and comments on two recent cross-sectional studies on the effects of third- and second-generation OCs on activated protein C (APC) sensitivity. In the comparative studies, the only difference in hemostatic parameters between DSG/GSD- and LNG- or NGM-containing OC users was a tendency towards higher factor VII (FVII) levels with DSG/GSD OCs. Differential effects on APC sensitivity were observed with the endogenous thrombin generation potential (ETP) assay, but not with the classical APC resistance test. FVII is not a risk marker for VTE, but is affected by dietary fat, estrogens and androgens and may interfere with the ETP assay. As no differences in established VTE risk markers were observed, there is no plausible reason for a differential risk of VTE with DSG/GSD- and LNG-containing OCs. In fact, the lack of differences with regard to established risk markers of VTE gives further support to the findings of the most recent epidemiological studies, which have not found any difference in the risk of VTE between third- and second-generation OCs.

Severe congenital factor VII (FVII) deficiency is a rare bleeding disorder. Prophylaxis with replacement therapy has been suggested to patients, yet the most beneficial dosing regimens and therapy intervals are still to be defined. Due to the lack of evidence-based data, we hereby present our experience with long-term administration and monitoring primary prophylaxis in children with severe FVII deficiency and an extremely high bleeding risk. Four children with familial FVII deficiency, treated by prophylactic recombinant activated factor VII (rFVIIa), 15-30μg/kg/dose, given 2-3 times weekly since infancy, are discussed. Clinical follow up and monitoring laboratory assays, including thrombin generation, measured at various time points after prophylactic rFVIIa administration are presented. Among our treated patients neither FVII activity nor thrombin generation parameters (both already declined 24h post rFVIIa administration) were able to predict the impact of prophylaxis, and could not be used as surrogate markers in order to assess the most beneficial treatment frequency. However, the long clinical follow-up and comprehensive laboratory assessment performed, have shown that early primary prophylaxis as administered in our cohort was safe and effective.

To make plasma readily available to treat major hemorrhage, some centers are internationally using either thawed plasma (TP) or "never-frozen" liquid plasma (LP). Despite the routine use of both, there are limited data comparing the two. The hemostatic properties of LP were evaluated and compared to TP in a paired study.

Two ABO-matched plasma units were pooled and split to produce 1 unit for LP and 1 unit for TP. Samples of TP and LP, stored at 2 to 6°C, were tested for a range of coagulation factors, thrombin generation, and rotational thromboelastometry. An additional 119 units of LP were collected and analyzed for markers of contact activation (S-2302 cleavage) and cellular content.

LP and TP were compared, up to 7 days of storage, with results showing no difference in the rate of change over time for any variable measured. When compared to Day 5, LP on Day 7 showed no difference for any factors measured; however, on Day 11 Factor (F)II, FV, FVII, and protein S (activity) were lower. Analysis of 119 LP units showed that 26 of 119 (22%) exhibited cold-induced contact activation by Day 28.

LP and TP were comparable in terms of hemostatic variables up to 7 days of storage. Decreasing coagulation factor activity along with an increased activation risk during storage of LP needs to be balanced against availability to supply and clinical need when considering using LP with more than 7 days of storage.

Twenty-three patients with congenital factor VII (FVII) deficiency, belonging to 9 kindreds were studied. Immunological variants were classified according to the relationship between FVII coagulant activity (FVIIC) and the level of FVII antigen (FVIIAg), considering 3 previously described groups: VII-, VII+ and VIIR. Activation variants were determined by the reactivity pattern with three different thromboplastins. One patient was classified as VII-, 16 as VII+, and 6 as VIIR. Three patients belonging to the same kindred showed a Padua 2 FVII deficiency, and 1 patient showed a Padua 1 variant. There was no correlation between antigenic or activation variants and severity of bleeding tendency. Classical autosomal recessive mode of inheritance was observed in VII- and VII+ families. Nevertheless, a possible autosomal dominant trait was observed in VII+ kindreds.

Menorrhagia is a well-recognized complication of inherited bleeding disorders. In the past, the only viable option for women who were unresponsive to medical therapy was hysterectomy. Endometrial ablation has been recently developed as an alternative therapy for these patients and is associated with decreased morbidity. We report the successful use of activated recombinant factor VII (FVIIa) and endometrial ablation in the treatment of excessive menstrual blood loss in a 34-year-old women with severe factor VII (FVII) deficiency. Recombinant FVIIa (40 microg/kg) was administered pre-operatively and every 6 h (20 microg/kg) for 24 h postoperatively. The procedure was uncomplicated with a 200 ml surgical blood loss. FVIIa was used because it allowed FVII replacement with a recombinant product and also has the ability to bind to tissue factor expressed at the site of vascular injury, resulting in site-specific thrombin generation. We believe that endometrial ablation with recombinant VIIa should be considered in patients with severe FVII deficiency and menorrhagia unresponsive to medical therapy.

Recombinant activated factor VII (rFVIIa) and plasma-derived factor VII (pdFVII) are used to prevent bleedings in severe FVII deficient patients, despite their short half-lifes. It is suggested that FVII levels of 15-20 IU/dL are sufficient to maintain hemostasis. We analyzed the pharmacodynamic effects of FVII substitution therapy in the Nijmegen Hemostasis Assay (NHA) that simultaneously measures thrombin and plasmin generation. Ten severe FVII deficient patients were treated with 20 μg/kg rFVIIa or 25 IU/kg pdFVII in a cross-over design. Thrombin generation lag-time (TG-LT) was identified as an effect-response parameter. Pharmacodynamic analysis using a maximum effect model showed 50% reduction of the TG-LT effect at ~2 IU/dL FVII activity for both rFVIIa and pdFVII. The FVII activity to obtain TG-LT comparable to the upper limit of normal range in healthy controls (4 min) was given by the effective concentration (ECnormal), showing sufficient hemostasis at 3-4 IU/dL FVII activity. No association was seen between FVII activity and other thrombin or plasmin generation parameters as measured by NHA. In conclusion, 3-4 IU/dL FVII activity seems sufficient to maintain hemostasis in patients with severe FVII deficiency during prophylaxis. These data may suggest a potential value for measurement of TG-LT in the monitoring of FVII(a) therapy.

OBJECTIVE

Although many F7 DNA variants have been described to be associated with alterations in factor VII (FVII) levels, the correlation of functional levels of FVII with disease (i.e. bleeding) is highly variable indicating that other factors are likely involved in producing this phenotype.

METHODS

We studied two unrelated Spanish families, identified from two asymptomatic propositi with FVII:C levels lower than 1% and 3%. Family members showed a wide range of FVII:C levels. Amplification and direct DNA sequencing of the F7 (promoter, exons, 3'-UTR and a large proportion of introns) identified the genetic variants involved.

RESULTS

We characterized 3 mutations in the F7 coding region (homozygous Q100R in one patient, and double heterozygosity for M298I and G331S in another patient). We also found 16 new DNA polymorphisms. The high variability of FVII levels in family members with the same mutation shows that the inheritance of FVII phenotypes is extremely complex and suggests that polymorphisms might play an important role in modulating FVII levels, and ensuring hemostatic balance under pathologic conditions.

CONCLUSIONS

These results highlight the importance of a concerted effect of multiple genetic factors in determining FVII levels. Since there is evidence that FVII levels constitute a risk factor for coronary heart disease and considering the importance of F7 DNA polymorphisms in determining FVII levels, further analyses of these polymorphisms should yield information to aid the understanding of the quantitative variation in FVII levels and the relative genetic risk for cardiovascular disease in the general population.

We investigated the frequency of the factor VII Gln353 (FVII Gln353) allele in Japan, where coronary artery disease is much less common and factor VII coagulant activity (FVIIc) is lower than in Western countries. Japanese males (n = 144) aged 40-59 years living in 2 different districts were studied, and the FVIIc and activated factor VII (FVIIa) levels were measured with human (FVIIa Hum) and bovine soluble tissue factor (FVIIa Bov). The frequency of the FVII Gln353 allele in the 2 districts was 0.026 and 0.052 (combined: 0.034), which was about one third of that in a European population. Thus, the lower FVIIc level in Japanese is not due to the effect of FVII Gln353 allele. Ten individuals with the Gln353 allele showed a 39% decrease of FVIIa Hum levels and a 29% decrease of the FVIIa Bov level compared with 134 individuals homozygous for the FVII Arg353 allele. These decreases of FVIIa were greater than the decrease of FVIIc (17%), suggesting that FVII Gln353 may be difficult to activate in vivo. The marked decrease of FVIIa levels in individuals with the FVII Gln353 allele suggests that they are genetically protected against cardiovascular disease irrespective of ethnic background, by virtue of their decreased FVIIa level.

Being a putative predictor of ischemic heart disease, the measurement of factor VII (FVII) coagulant activity will be presumably requested to clinical laboratories with increasing frequency. To assess the influence on FVII assays of different thromboplastins and FVII-deficient plasmas we compared performances of all possible combinations of 5 thromboplastins and 6 deficient plasmas. The reproducibility of the clotting times of the dose-response curves for human and rabbit thromboplastins were acceptable (CV lower than 7%), whereas bovine thromboplastin had a higher CV. Reproducibility was very similar for all deficient plasmas when they were used in combination with a given thromboplastin. Responsiveness of the dose-response curve did not depend on the deficient plasma but rather on the thromboplastin: one rabbit thromboplastin was the least responsive, the bovine thromboplastin the most responsive, the human and the remaining two rabbit thromboplastins had intermediate responsiveness. Assay sensitivity to cold-activated FVII varied according to the thromboplastin: the bovine thromboplastin was the most sensitive, the human thromboplastin the least sensitive, of the three rabbit thromboplastins two were relatively sensitive, one was almost insensitive. In conclusion, our results indicate that thromboplastin rather than deficient plasma is the crucial factor in the standardization of FVII assay.

Von Willebrand, who described a bleeder family from Aland in 1926 in whom the index patient died at the fourth menses, stated, "the trait seems to be seen among women." Menorrhagia is defined objectively as a menstrual blood loss of at least 80 mL. However, even though 5% of women aged 30 to 49 years consult their general practitioner and 12% of gynecologic referrals are for menorrhagia, the diagnosis is difficult. A pictorial bleeding assessment chart (PBAC) has a specificity and sensitivity of more than 80%, with a score of>> or = 100 being equivalent to more than 80 mL of blood loss. Using this chart to screen 150 women with menorrhagia who attended a gynecology clinic, an inherited bleeding disorder was diagnosed in 17%. Menorrhagia with onset at the menarche was predictive of an inherited bleeding disorder in 65% of von Willebrand's disease (vWD) and 67% of factor XI (FXI)-deficient patients. A retrospective survey in patients with inherited bleeding disorders using the PBAC showed menorrhagia in 74% of patients with vWD, 57% of carriers of hemophilia A or B, and 59% of FXI-deficient patients, compared with 29% of control individuals. Menorrhagia was the most common symptom in 60% of patients with FVII deficiency studied. Menorrhagia in women with bleeding disorders can be controlled with tranexamic acid with good effect. More recently, a desmopressin acetate (DDAVP) spray has been shown to achieve good FVIII and von Willebrand factor (vWF) levels and is efficacious for women with these deficiencies. The oral contraceptive pill may be useful. Since bleeding disorders are found in a substantial number of women with menorrhagia, it is important that such patients are investigated for these disorders before invasive procedures are done; hysteroscopy and hysterectomy in these patients are associated with a high rate of postoperative bleeding.

Human semen spontaneously coagulates into a semisolid mass and then wholly liquefies in a process that may have some similarity to that of normal blood. This well described phenomenon is referred to as coagulation and liquefaction of semen. Besides other active components of the haemostatic system, semen contains a significant amount of functional tissue factor (TF). However, TF needs factor (F)VII in order to exert it actions. In this study, we assessed human semen for the presence of FVII and FVIIa, and related their levels to conventional fertility parameters. Using a functional, one stage, clotting assay based upon the prolongation of the prothrombin clotting time, using the ACL 300R analyser and an Imubind FVIIa ELISA assay, FVII and FVIIa levels were measured in 97 semen specimens obtained from sub-fertile (sperm counts <20 x 10(6)/mL), normally fertile (sperm counts>>or=20 x 10(6) but <60 x 10(6)/mL), fertile sperm donors (sperm counts>>or=60 x 10(6)/mL), vasectomized subjects and in a pooled normal semen parameters group (categorization into groups was based on the World Health Organization guidelines on fertility criteria). In addition, conventional semen parameters were analysed on all semen samples. Both FVII and FVIIa were quantifiable in human semen. The mean levels of FVII and FVIIa were 4.4 IU/dL and 12 ng/mL respectively. Despite the observed variations of FVIIa levels in the studied groups they did not meet statistical significance when the groups were tested against each other. However, seminal FVIIa levels showed a significant positive association with semen liquefaction time, sperm motility and semen volume. The anti-sperm antibodies and sperm-agglutination groups were also associated with raised seminal FVIIa levels. We observed no significant relationship between FVIIa levels and total sperm concentration, sperm count per mL (sperm density), sperm progression and days of sexual abstinence. This study demonstrates that human semen contains appreciable amounts of FVII and FVIIa. It is possible to quantify these using commercially available assays. There also appears to be a direct correlation between the levels of these factors and certain seminal parameters. This finding reinforces the concept of an active clotting system in human semen, by establishing the missing link in the activation of a TF-dependent pathway.

Congenital coagulation factor (F) VII deficiency is a rare bleeding disorder caused by mutations in the F7 gene. The missense factor FVII variant p.Q160R is the disease-causing mutation in all Norwegian FVII deficient patients and results in reduced biological activity and antigen levels of FVII in patient plasma. Previous in vitro studies on this variant demonstrated impaired intracellular trafficking and reduced secretion, possibly due to protein misfolding. The aim of the study was therefore to assess the impact of chemical chaperones on cellular processing and secretion of this variant using a cell model based on overexpression of the recombinant protein.

Through screening of compounds, we identified 4-phenylbutyrate (4-PBA) to increase the secretion of recombinant (r) FVII-160R by ~ 2.5-fold. Additionally, treatment with 4-PBA resulted in a modest increase in specific biological activity. Intracellular localization studies revealed that upon treatment with 4-PBA, rFVII-160R was secreted through Golgi and Golgi reassembly-stacking protein (GRASP)-structures.The present study demonstrates that the chemical chaperone 4-PBA, restores intracellular trafficking and increases the secretion of a missense FVII variant with functional properties in the extrinsic coagulation pathway.

BACKGROUND

The relation between Factor VII (FVII) and tissue thromboplastin is not completely clarified, yet. Three FVII abnormalities, FVII Padua (Arg304Gln), FVII Nagoya (Arg304Trp) and FVII Shinjo or Tondabayshi (Arg79Gln) show different FVII activity according to the tissue Tissue Factor (TF) used in the assay system (rabbit brain, human placenta or human recombinant and ox brain).

OBJECTIVE

To investigate the possible existence of common conformational changes with regard to different tissue factors in these three FVII variants.

METHODS

Crystal structure analysis and "visual inspection" of FVII were deeply performed to select a crystallographic template for the in silico mutagenesis procedure of FVII Arg79Gln, Arg304Gln and Arg304Trp.100ns 300K NVT large-scale molecular dynamics simulation on GPU were applied to the models of FVII. The aims of this run was to describe at molecular level the influence of the mutation on the protein structure and function.

RESULTS

The molecular modelling of those three variants has shown common features in spite of the different location of the mutation involved (the first epidermal growth factor for the Arg79Gln and the catalytic region for the Arg304Gln or Arg304Trp). Molecular dynamics studies have shown in fact that the mutant FVII, shows a decreased flexibility or freezing of the protein conformation of FVIIa with regard to TF. This results in the formation of a defective FVIIa-TF complex that justifies the different clotting results observed in these variants according to the TF used.

CONCLUSIONS

The conformational studies may supply useful information on the structure- function relation of clotting factors.

The reagents most frequently used for FVII activity assay are obtained by rabbit brain or human placenta. In recent years, human recombinant thromboplastins have received great attention. FVII activity in FVII deficiency is usually low, regardless of the thromboplastin used. There are a few exceptions to this rule. These are represented by FVII Padua (Arg304Gln), FVII Nagoya (Arg304Trp), and FVII (Arg79Gln). In these three instances, clear discrepancies were noted in the FVII activity depending on the thromboplastin used. This indicates that at least two areas of FVII are involved in tissue binding, namely an epidermal growth factor domain of the light chain (Arg79Gln) and the catalytic domain (Arg304), controlled by exons 4 and 8, respectively. Since these three variants are cross reactive material positive, namely they are Type 2 defects, all other variants with normal antigen should be investigated by a panel of at least three tissue thromboplastins (rabbit brain, human tissue or human recombinant, and ox brain derived) in order to obtain a satisfactory classification.

Thrombocytopenic patients refractory to platelet concentrates (PC) could be treated during bleeding episodes with the recombinant activated FVII (rFVIIa). However, monitoring of administration of the rFVIIa or a response to platelet substitution therapy in thrombocytopenia patients is not well documented so far. Using of whole blood ROTEG analysis we monitored the changes in haemostatic parameters following in vivo platelet concentrate administration compared to ex vivo rFVIIa administration in patients with a severe to mild thrombocytopenia secondary to haemato-oncological disease. We use non-activated thrombelastography (NATEG) and a mild intrinsic activation thrombelastography (INTEG). NATEG analysis was sufficiently sensitive to monitor changes following PC and rFVIIa administration. Both, platelet infusion and rFVIIa treatment induced significant shortening of clotting time (CT) and clot formation time (CFT) parameters (p<0.05). When we compared the effect of platelet vs. rFVIIa treated whole blood by NATEG analysis we did not found any significant difference. Analysis with INTEG system was less sensitive and changes in CT and CFT were not significant. The monitoring with thrombelastography could enable efficient application of platelet concentrate and furthermore the using of rFVIIa as an alternative treatment of patients refractory to platelet infusion or with allergic reactions.

BACKGROUND

Abdominoplasties carried out in patients previously underwent gastroplasty present high rates of complications, including increased bleeding in the intra- and postoperative periods.

METHODS

This study evaluated bleeding, coagulation parameters (coagulogram, dosage of fibrinogen, FII, FV, FVII, FVIII, FIX, FX, and FXII), and thromboelastography in two groups of women who underwent abdominoplasties: a group with a history of gastroplasty by the Fobi-Capella technique (group I) and the other group without a history of obesity (group II). Analyses were performed before, during, and after each surgical procedure. Vitamins K and C were also dosed. Bleeding was measured by counting and weighing compresses at the end of each surgery, and the withdrawn surgical specimens were weighed.

RESULTS

Statistically, group I patients had more bleeding than group II in all evaluated operative periods (p = 0.007). There was no significant change in the coagulogram or decrease in coagulation factors that could be associated with increased bleeding in any of the analyzed groups. Thromboelastography, which provides a comprehensive analysis of thrombin generation and of hemostasis in real time, did not differ between groups. Vitamin K was significantly increased in group I patients (p = 0.019). The weight of the surgical specimens removed was significantly higher in group I (p = 0.007) and there was correlation of the weight with the degree of bleeding.

CONCLUSIONS

The results of this study demonstrate an increase of bleeding during the intraoperative period of abdominoplasty in patients with a history of gastroplasty that it is not due to changes in hemostasis.

METHODS

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

FVII deficiency is a rather rare inherited hemocoagulation disorder that predisposes to hemorrhagic events, especially from mucous membranes, that are not predictable and severe as in hemophilia A. This defect produces prolonged prothrombin time (PT), reduced activity of FVII and normal activated partial thromboplastin time (aPTT). We report the case of a 43-year-old obese woman with severe deficiency of factor VII (FVII), probably genetic in nature, and meno-metrorrhagia associated with multiple fibromas of uterus. Our patient had no history of bleeding in infancy and young age, and in the past, before the disease was diagnosed, underwent major surgery operations (thyroidectomy and caesarian section) without hemorrhage. Patient's relatives with mild heterozygous deficiency of FVII (the father, a brother, a sister, a sister's daughter and the patient's son) did not show any bleeding tendency. This case report is discussed in the light of literature data ((source: Medline from 1964 to 1996). The different forms of congenital (isolated or combined with other clotting disorders) and acquired FVII deficiency, with the appropriate therapies, are reviewed. The clinician must consider FVII deficiency in cases of recurrent bleeding, and this disease, even if rather rare, should not be underestimated in clinical practice because it is potentially fatal.

BACKGROUND

The homologous coagulation factor X (FX), VII (FVII), IX (FIX) and protein C (PC) display striking differences in the carboxyl-terminus, with that of FX being the most extended. This region is essential for FVII, FIX and PC secretion.

OBJECTIVE

To provide experimental evidence for the role of the FX carboxyl-terminus.

METHODS

Recombinant FX (rFX) variants were expressed in multiple eukaryotic cell systems. Protein and activity levels were evaluated by ELISA, coagulant and amidolytic assays.

CONCLUSIONS

Expression of a panel of progressively truncated rFX variants in HEK293 cells revealed that the deletion of up to 21 residues in the carboxyl-terminus did not significantly affect secreted protein levels, as confirmed in HepG2 and BHK21 cells. In contrast, chimeric rFX-FVII variants with swapped terminal residues showed severely reduced levels. The truncated rFX variants revealed normal amidolytic activity, suggesting an intact active site. Intriguingly, these variants, which included that resembling the activated FXβ form once cleaved, also displayed remarkable or normal pro-coagulant capacity in PT- and aPTT-based assays. This supports the hypothesis that subjects with nonsense mutations in the FX carboxyl-terminus, so far never identified, would be asymptomatic.

CONCLUSIONS

For the first time we demonstrate that the FX carboxyl-terminal region downstream of residue K467 is not essential for secretion and provides a modest contribution to pro-coagulant properties. These findings, which might suggest an involvement of the carboxyl-terminal region in the divergence of the homologous FX, FVII, FIX and PC, help to interpret the mutational pattern of FX deficiency.

BACKGROUND

Octaplas® LG is a second-generation solvent/detergent-treated plasma that offers an additional safety benefit by prion elimination. The stability of clotting factors of the new S/D plasma after thawing has not been investigated yet. This study intended to measure the time course of fibrinogen, FII, FV, FVII, FVIII, FIX, PC, fPS and PI through storage at 2-6°C over 6 days.

METHODS

We investigated 20 plasma bags (five bags per blood group) and measured fibrinogen, FII, FV, FVII, FVIII, FIX, PC, fPS and PI immediately after thawing and after 2, 4, 6, 24, 48, 72, 96, 120 and 144 h storage at 2-6°C. Five separate plasma bags were thawed and stored at 2-6°C for microbiological assessment. After 6 days samples were drawn for blood cultures that were incubated for six more days.

RESULTS

After 6 days FII, FIX and PC showed no significant changes. FV (-16%, p<0.001), FVII (-19%, p<0.001), FVIII (-19%, p<0.001), FXI (-13%, p<0.0001) and fPS (-4%, p<0.0007) decreased significantly. PI levels were stable at 56%. The microbiological investigation showed no bacterial contamination.

CONCLUSIONS

In Octaplas® LG plasma clotting factors decreased slightly through storage of 6 days. PI levels were remarkably higher and stable over time in the new Octaplas® LG. Stability of stored Octaplas® LG was limited by the decrease of FVIII to 53%, which may warrant storage up to 24h from a quality assurance point of view. This could result in reduced plasma wastage and costs for healthcare givers.

Background. The use of plasma frozen within 24 hrs is likely to increase. Whole blood (WB) and buffy coats (BCs) can be held for a few hrs or overnight before processing. Methods. Twenty-four bags of WB for plasma and 12 bags for platelet (PLT) concentrates were collected. The fresh frozen plasma (FFP) was prepared within 6 hrs. I-FP24 and II-FP24 samples were prepared either from leukodepleted WB that was held overnight or from WB that was held overnight before leukodepletion. The PLT concentrates (PCs) were prepared from BCs within 6 hrs (PC1) and within 18 to 24 hrs (PC2). The typical coagulation factors and some biochemical parameters were determined. Results. Compared to the FFP samples, the levels of FVII and FVIII in the I-FP24 and II-FP24 samples decreased significantly. The pH, Na(+), LDH, and FHb levels differed significantly between II-FP24 and FFP. Compared to PC1, PC2 exhibited lower pH, pO2, and Na(+) levels, a higher PLT count, and increased pCO2, K(+), Lac, and CD62P expression levels. Conclusion. FP24 is best prepared from WB that was stored overnight at 4°C and then leukodepleted and separated within 24 hrs. PCs are best produced from BCs derived from WB that was held overnight at room temperature.

Factor VII (FVII) deficiency is the most common of the Rare Inherited Coagulation Disorders. The inheritance is autosomal recessive but there is variable penetrance. Overall there is poor correlation between the FVII level and the bleeding phenotype. Heterozygotes may have significant bleeding and severe homozygotes, or compound heterozygotes can be asymptomatic. Typically, homozygotes have FVII levels <10% and heterozygotes have levels above that. In most cases bleeding is uncommon with FVII levels>10-20%. A personal and family history is essential to determine the bleeding risk and to plan for surgical and obstetrical prophylaxis. Severe bleeding complications including central nervous system bleeding, gastrointestinal system bleeding and bleeding into the joints occurs in 10-15% of FVII deficient patients. Mucocutaneous bleeding is a common symptom but 30% of patients are asymptomatic. Fifty to 69% of women have heavy menstrual bleeding. Due to the limited number of publications regarding this rare disorder there are no consensus guidelines. There is registry data which has led to the best recommendations for treatment of bleeding episodes, initiation of long-term prophylaxis in addition to surgical plus ante and peripartum prophylaxis. Recombinant FVII concentrate is the best replacement therapy and a review of treatment and prophylaxis dosing is discussed.