A CLINICAL AND FAMILY STUDY OF HEREDITARY PROCONVERTIN (FACTOR VII) DEFICIENCY

Is prophylaxis required for delivery in women with factor VII deficiency?

Factor VII (fVII) deficiency is a rare congenital bleeding disorder in which fVII activity level and bleeding tendency do not completely correlate. Pregnancy and delivery present a significant haemostatic challenge to women with fVII deficiency. Treatment with recombinant factor VIIa (rfVIIa) carries a thrombotic risk and the literature is not clear whether prophylaxis is necessary prior to delivery. The aim of this study was to define management, haemorrhagic and thrombotic complications of pregnant women with fVII deficiency through a systematic review. Medical databases (PubMed, MEDLINE, CINAHL, Academic Search Premier, Cochrane Library, Web of Science and Scopus) were searched using "factor VII deficiency" and "pregnancy" or "surgery." Overall 34 articles, four abstracts, and three institutional cases were reviewed. Literature from 1953 to 2011 reported 94 live births from 62 women with fVII deficiency. The median fVII activity was 5.5%. Haemostatic prophylaxis was used in 32% of deliveries. Without prophylaxis, 40 vaginal deliveries and 16 caesarean sections were completed. The odds of receiving prophylaxis were 2.9 times higher in women undergoing caesarean section compared to vaginal delivery. Post-partum haemorrhage occurred in 10% of deliveries with prophylaxis and 13% of deliveries without prophylaxis. The fVII level did not significantly differ between women who did and did not receive prophylaxis. We present the only systematic review of the management of pregnancy in fVII deficient women. No difference in post-partum haemorrhage was seen in deliveries with and without prophylaxis. Therefore, we recommend that rfVIIa be available in the case of haemorrhage or surgical intervention, but not as mandatory prophylaxis.

Carriers of factor VII deficiency are not always asymptomatic

Seven children, referred because of bleeding symptoms, proved to be heterozygotes for factor VII deficiency. Abnormal bruising was the commonest symptom (6/7), followed by postoperative bleeding (4/7). One case had recurrent epistaxis. Results on the patients and their families are presented. Prothrombin times were prolonged by 2-3 s and factor VII assays ranged from 25 to 55% (mean 38%). The cases are reported because they bled excessively: yet it is usually stated that carriers for factor VII deficiency are symptom-free. One case of homozygous factor VII deficiency is also described: the parents (who are heterozygotes) were symptom-free.

Arterial and venous thrombosis in rare congenital bleeding disorders: a critical review

A thorough review of the literature and of personal files has allowed the gathering of 81 patients with rare congenital bleeding disorders and thrombotic phenomena. Sixteen of these patients had congenital afibrinogenemia, eight involved factor V deficiency, 20 factor VII defects, 33 factor XI deficiencies and only one, a factor XIII defect. Altogether 42 patients showed arterial thrombosis (myocardial infarction [MI] in 28 cases; ischemic stroke in 4; arterial occlusion in 8; 2 patients with disseminated intravascular coagulation (DIC)). Ages varied between 13 and 74. Twenty-two patients were males and 16 females. In four cases, sex was not reported. There were three fatalities: two after a MI and one because of heart failure. With regard to venous thrombosis: 9 patients had pulmonary embolism, 15 patients had deep vein thrombosis, 9 patients had both pulmonary embolism and deep vein thrombosis; 1 patient had superficial vein thrombosis, whereas, 5 cases had an unusual site venous thrombosis (two portal systems, two cerebral sinuses, one inferior vena cava) for a total of 39 cases. Age varied between 3 and 86. In this case, 20 patients were males and 17 were females. In two cases, sex was not reported. There were three fatalities: two because of pulmonary embolism and one because of inferior vena cava thrombosis. The fact that thrombosis has never been described in patients with factor II or factor X seems to underscore the central antithrombotic role that these two factors have in the coagulation system.

Factor VIIa replacement therapy in factor VII deficiency

Factor (F)VII deficiency is an autosomal recessive disorder for which a replacement therapy is not universally available; recombinant FVIIa has been utilized as a therapeutic substitute. As FVII competes with FVIIa for binding to tissue factor in initiating the extrinsic pathway of blood coagulation, a lower dose of FVIIa replacement in cross-reacting material-negative (CRM-) individuals can achieve hemostasis. Three coagulation models (computational, synthetic and in vitro whole blood) were used to predict the FVIIa levels needed to provide apparent hemostasis in a non-bleeding state. Our whole blood results show that a 'normalized' coagulation profile for FVII-deficient individuals has an initiation phase that ends at 5.8 +/- 0.5 min (clot time) and the propagation phase of thrombin generation (thrombin-antithrombin III) yields a maximum concentration of 380 +/- 29 nmol L(-1). When CRM- FVII-deficient subjects were infused with a prophylactic dose of 23 micro g kg(-1) of recombinant FVIIa, 6-8 h postinfusion resulted in a comparable normalized whole blood profile. This FVIIa concentration (0.3-0.7 nmol L(-1)/equivalent dose: 0.8-1.8 micro g kg(-1)) is approximately 1/10 that currently used in treating FVII-deficient individuals and suggests that therapies should be altered relative to the concentration of the FVII zymogen.

Thrombosis in inherited factor VII deficiency

Thrombosis in congenital factor (F) VII deficiency was investigated through extensive phenotypic and molecular-genetic studies. Patients with a history of thrombosis among 514 entries in the FVII Deficiency Study Group database were evaluated. Thrombotic events were arterial in one case, disseminated intravascular coagulation in another and venous in seven. Gene mutations were characterized in eight patients: three were homozygous, three compound heterozygous and two heterozygous. FXa and IIa generation assays were consistent with the genetic lesions. One patient was heterozygous for the FV Leiden and one for the FIIG20210A mutation. In seven patients, surgical interventions and/or replacement therapies had a close temporal relationship with thrombosis, while in the remaining, events were apparently spontaneous. Thromboses were not associated with any specific age, phenotype, mutation zygosity or thrombophilic abnormalities. In particular, severe FVII deficiency did not seem to offer protection from strong thrombosis risk factors such as surgery and replacement therapy.

Novel mutations in the Factor VII gene of Taiwanese Factor VII-deficient patients

The genetic defects of four Taiwanese patients with factor VII (FVII) deficiency were studied. FVII activity and antigen levels were < 1 u/dl and 125.7 u/dl (patient I), < 1 u/dl and < 1 u/dl (patient II), 3.4 u/dl and 5.9 u/dl (patient III), and 1.2 u/dl and 30.4 u/dl (patient IV) respectively. The 5' flanking region, and all exons and junctions were amplified using polymerase chain reaction and sequenced. Patient I was homozygous for a 10824C-->A transversion with Pro303-->Thr mutation in exon 8. In patient II, a heterozygous transversion, 9007+1G-->T at the IVS6, a heterozygous decanucleotide insertion polymorphism at -323 (both mutations present in his father) and a heterozygous deletion, del TC (26-27) in exon 1A (originating from his mother) were identified. Patient III had a homozygous 10961T-->G transversion with His348-->Gln mutation in exon 8. Patient IV had a heterozygous 10902T-->G transversion with Cys329-->Gly mutation in exon 8 (transmitted to her second son) and a heterozygous decanucleotide insertion polymorphism at -323 (transmitted to her third son). All but one of the FVII gene mutations detected in the four patients have not been previously reported. In conclusion, four novel mutations of the FVII gene in Taiwanese, including two missense mutations in exon 8, one point mutation at the exon 6 splice site and one deletion in exon 1A, were identified.

Clinical picture and treatment strategies in factor VII deficiency

Factor VII is a trace protein required for normal haemostasis. Deficiency of factor VII comprises a highly heterogeneous disease group. Factor VII deficiency can cause bleeding, in particular if factor VII is extremely low, but a few cases lacking factor VII function entirely or subtotally may not present with a history of bleeding. Bleeding problems are not often reported in patients having a factor VII:C level at 10-15% of normal or more. Bleeding is frequently of mucocutaneous type, but the whole array of haemophilic bleeding may also occur. To control bleeding, during surgery in particular, substitution is required in the severe case of factor VII deficiency, but clinical studies documenting which correctional levels of factor VII:C to aim are lacking. It appears that a critical low level (trough) value at 10-15% may be anticipated, but clear documentation does not exist. Substitution programmes may include plasma or plasma derived factor IX concentrates of lower degrees of purity, so-called prothrombin complex concentrates that also are relatively impure, and pure factor VII concentrates. An alternative is a recombinant factor VIIa molecule. However, this concentrate has not received license in a number of countries. Thrombotic manifestations appear to occur more often than expected in the factor VII deficient patients, some have been linked to the use of impure concentrates, others to preexisting thrombophilic risk factors, but some are unexplained and may bear a relationship to the deficiency state of factor VII itself. Controlled clinical trials are highly warranted in this rare bleeding condition.

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

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.

African-American factor VII-deficient variants in Georgia (FVII variants)

We studied African-American Factor (FVII)-deficient variants and carriers in Georgia by measuring their levels of FVII antigen (FVIIAG) and FVII procoagulant (FVIIC). Factor VIIAG was determined using enzyme-linked immunoassay (ELISA), whereas FVIIC was measured in two ways: 1) by fibrin clotting methods that employed human recombinant (HRFVIIC), human placental (HPFVIIC), rabbit brain (RBFVIIC), and bovine brain (BBFVIIC) thromboplastins; and 2) by an amidolytic method (AMFVIIC). Prothrombin time tests (PT) were also performed by standard methods. These 4 FVII-deficient patients and 3 carriers demonstrated the following results: PT: 18.2 +/- 6.5 sec; FVIIAG: 73.0 +/- 14.9%; HRFVIIC: 30.6 +/- 20.3%; HPFVIIC: 30.5 +/- 21.4%; RBFVIIC: 25.3 +/- 21.4%; BBFVIIC: 30.6 +/- 17.5%; AMFVIIC: 44.1 +/- 18.3%. We conclude that a group of clinically mild African-American FVII-deficient variants exists in Georgia. This group is characterized by the presence of FVIIAG and decreased FVIIC, using a variety of thromboplastins; and excellent correlation was noted for both human thromboplastins.

Uncomplicated stereotactic and open neurosurgical procedures in patients with factor VII deficiency

Factor VII deficiency is characterized by epistaxis, bruising, hemarthrosis, menorrhagia, gastrointestinal bleeding, hematuria, and intracranial hemorrhage during infancy. Causes of acquired factor VII deficiency include liver disease, Vitamin K deficiency, and warfarin administration. Congenital factor VII deficiency is an autosomal recessive disorder, with the homozygotes having a severe deficiency and the heterozygotes a moderate deficiency of factor VII. Orthopedic, gynecological, cardiothoracic, and abdominal surgical procedures have been successfully performed in patients with factor VII deficiency both with and without factor VII replacement. We present two patients with moderate and moderately severe factor VII deficiency who successfully underwent intracranial procedures using plasma during the perioperative period for factor VII replacement. One patient successfully underwent stereotactic placement of mesial temporal lobe depth electrodes and subdural strip electrodes followed by anterior temporal lobectomy for medically refractory seizures. The second patient successfully underwent craniotomy for an olfactory groove meningioma. No bleeding complications were encountered with any of the three intracranial procedures performed. These cases represent the first reported cases of successful intracranial procedures in patients with factor VII deficiency, other than shunting procedures performed for intraventricular hemorrhage during infancy.

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

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 factor-induced 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.

Hereditary factor VII deficiency in pregnancy: peripartum treatment with factor VII concentrate

This report describes pregnant sisters with severe factor VII deficiency and peripartum management with factor VII concentrate. In this family, two affected members had previously developed severe postpartum hemorrhage when managed with fresh frozen plasma. Therapy-related complications owing to plasma infusion included viral disease transmission and pulmonary edema. Therefore, to lessen the risks of complications, specific factor therapy was initiated shortly before parturition in both patients. Factor VII concentrate was administered prior to delivery and every 6 hr for the next 72 hr to keep trough levels at approximately 10%. Based on peak and trough levels, the mean factor VII half-lives were determined to be 3.6 and 5.7 hr. Use of the concentrate was associated with uncomplicated delivery and minimal postpartum bleeding.

Rare factor VII variant inherited through genetic variant in proband's mother and another genetic variant in proband's father

An 11-year-old girl with hereditary factor-VII deficiency and her family have been studied for factor VII coagulation activity (VII:C) and factor VII antigen level (VII:Ag). The proband had 11% VII:C, whereas her VII:Ag was at a level that corresponds to about 50% coagulation activity. Forty-two members of the proband's family were tested. This study disclosed that the proband's factor VII deficiency had been inherited through both her mother and her father. Although her father was dead, testing of her father's family showed a factor VII defect of the type VII+ variant, that is, normal production of VII:Ag but reduced VII:C. The maternal side of her family was found to have reduced but identical levels of VII:C and VII:Ag (variant VIIR). The proband's factor VII deficiency is therefore apparently inherited through two different variants, and that could explain this rare genetic type of factor VII deficiency. To our knowledge no such variant has ever been described.

Blood coagulation changes in homocystinuria: effects of pyridoxine and other specific therapy

The aim of this study was to investigate the blood coagulation changes in three patients with homocystinuria, in baseline condition and during therapy. At baseline, antithrombin III activity and factor VII levels were reduced in all three patients; antithrombin III protein and protein C antigen were also slightly lowered in one patient, and factor X in another. beta-Thromboglobulin, a measure of platelet activation, was increased in one case. During pyridoxine treatment, antithrombin III activity was rapidly restored to normal; factor VII increased and beta-thromboglobulin decreased. These data suggest that, in addition to platelet activation, abnormalities of blood clotting, and particularly reduction of antithrombin III, may play a role in the thrombotic tendency associated with homocystinuria. The nature of these clotting alterations is still uncertain, but their improvement during active metabolic treatment suggests that the defect in amino acid transsulfuration of homocystinuria may directly affect synthesis or activity of some liver-dependent clotting factors.

Monoclonal anti-human factor VII antibodies. Detection in plasma of a second protein antigenically and genetically related to factor VII

Several murine monoclonal anti-human Factor VII antibodies were produced using hybridoma technology. Two noncompetitive monoclonal antibodies were used to examine by Western blotting the Factor VII cross-reactive material (CRM) in normal human plasma and three commercially available congenitally Factor VII-deficient plasmas, and to construct a facile "sandwich" immunoassay for plasma Factor VII. A second, previously undescribed, form of Factor VII CRM was detected in human plasma, which on Western blotting stained with an apparent intensity 5-8% that of Factor VII. This glycoprotein, tentatively called VII*, has a molecular weight 4,500 D less than Factor VII, lacks detectable Factor VII functional activity, does not bind to barium citrate, and is not recognized by a monoclonal antibody that recognizes Factor VII but not alpha-chymotrypsin-treated Factor VII. VII* was not proteolytically produced from Factor VII during in vitro coagulation or after infusion of human Factor VII into rabbits. As determined by Western blotting, the human hepatoma cell line, HepG2, cultured in the presence of vitamin K, secreted relatively greater levels of VII* in proportion to VII (75%) than that found in human plasma. Warfarin treatment of HepG2 cells decreased the quantity of VII secreted by 77%, whereas it only inhibited the secretion of VII* by 14%. Immunologic studies of the plasmas from a patient on chronic warfarin therapy and an individual given a short course of high dose warfarin therapy corroborated the in vitro synthetic studies obtained with HepG2 cells. The data are consistent with the production of VII* by posttranslational, proteolytic, modification of VII, that, at least in the HepG2 cells studied, occurs intracellularly. However, other mechanisms for the production of VII*, in particular, alternative RNA splicing of the transcript from a single gene, cannot be excluded.

Multiple extractions in a patient with factor VII deficiency

Multiple extractions were carried out in a patient with factor VII deficiency treated with prothrombin complex concentrate. Hemostasis and healing were completely satisfactory. The side effects of prothrombin complex concentrate are discussed.

Hereditary factor VII deficiency in a Chinese family

Hereditary deficiency of factor VII is demonstrated in a Chinese family. The proposita was a 32-year-old female with bleeding diathesis consisting of spontaneous ecchymosis, menorrhagia and recurrent haemarthrosis. The prothrombin time was prolonged and the prothrombin and proconvertin test was 10% of normal. The activated partial thromboplastin time and the Stypven-cephalin clotting time were normal. The prolonged prothrombin time could be corrected by the addition of normal serum, but not by adsorbed normal or coumadin plasma. The factor VII level was 3.6% of normal. One of her brothers had bleeding symptoms and died at age 25, suggesting that factor VII deficiency might have been present. 13 of her family members had partial deficiency of factor VII with plasma levels ranging from 24 to 50%. These results suggest an autosomal recessive inheritance with a homozygous state occurring in the proposita and possibly in her brother, and a heterozygous state occurring in 13 of her family members. Our study marks an extensive survey of factor VII deficiency in an Oriental family.

Studies on a family with the factor VII defect

Investigations in a family with an isolated factor VII deficiency are reported. In one of the propositi VII Ag was reduced, in all other family members VII Ag was in the low normal range. Other investigators have observed various activation patterns of factor VII in four deficient families which were tested with thromboplastins from different sources. In contrast to most of these earlier studies the degree of activation with different thromboplastins was very similar regardless which thromboplastin was tested. These results confirm the heterogeneity of the factor VII defect. Platelet aggregation which was tested in one of the propositi with ADP, adrenaline, and collagen was found to be normal. No cold activation of factor VII was observed.

Binding of human factor VII and VIIa to monocytes

Human coagulation Factors VII and VIIa bind with equal affinity to monocytes stimulated with endotoxin. Equilibrium binding studies performed at 0 degrees C using 125I-labeled Factor VII and VIIa showed the dissociation constant (Kd) to be congruent to 82 pM with congruent to 3,600 binding sites/monocyte. Ca++ was required for Factor VII and VIIa interaction with monocytes (optimal CaC12 concentration greater than or equal to 2.5 mM) and binding was reversed by the addition of EDTA. The rate of conversion of Factor X to Xa in mixtures containing Factor VIIa and monocytes was directly related to the quantity of Factor VIIa bound to the monocyte surface. Thus the monocyte binding sites appear to represent tissue factor. Competition experiments showed that Factor VII and VIIa bind to the same monocyte sites and further, that unlabeled Factor VII and VIIa have the same affinity for the binding sites as the 125I-labeled proteins.

[Clinical studies of familial hereditary factor VII deficiency (author's transl)]

The discovery of a severe factor VII deficiency with increased bleeding tendency resulted in investigations of 22 members of the family. In the propositus and in two of his siblings a severe hypoproconvertinemia was demonstrated, a partial deficiency was found in ten persons. Studies of the family confirmed that this disorder is transmitted by an autosomal gene with intermediate penetrance. The mutated gene produces a severe deficiency in the homozygote and partial deficiency in the heterozygote. The parents of the homozygote patients were consanguineous. Hemorrhagic diathesis was noted only in patients with a severe factor VII deficiency. Causes for the variability of the clinical manifestations are discussed.

Warfarin skin necrosis. The role of factor VII

Necrosis of cutaneous and subcutaneous tissue is a rare complication of therapy of with oral anticoagulants, and is related to the use of loading-dose regimes. Three cases are reported, and demonstrate that the principal histopathological feature is thrombosis within the subcutaneous vasculature. The effect of large doses of anticoagulant on the levels of the vitamin K dependent clotting factors provides a satisfactory model for the temporal sequence of events in this syndrome. The occurrence of intravascular thrombosis with low or absent levels of Factor VII indicates that the intrinsic clotting system is of primary importance in venous thrombosis. This complication of anticoagulant therapy is not seen if loading-dose regimes are avoided.

Congenital factor VII deficiency. A report of four new cases

Four new cases with congenital homozygous factor VII deficiency are described. Factor VII levels were reduced to less than 1%, 3%, 8% and 10%, respectively. The incidence and severity of bleeding symptoms were well correlated with the measured factor VII activity. In the severe case of factor VII deficiency (less than 1%) a home treatment program was started because of severe recurrent hemarthroses. This entailed transfusions of 20 U/kg body weight prothrombin complex or factor VII concentrate in case of acute bleeding approximately every three weeks. These transfusions have been carried out successfully without any problems. In contradiction, two brothers with hypoproconvertinemia (factor VII 8% and 10% respectively) reached an age of more than 70 years. Despite replacement therapy postoperative bleeding followed one appendectomy, whereas no postoperative bleeding followed patients requiring Achilles tendon lengthening and an above knee amputation and only slight bleeding followed a tonsillectomy. Based on our experience we suggest that in patients with factor VII deficiency of less than 10%, when undergoing surgery, should be maintained a minimal factor VII activity of 10--15% during the first three postoperative days.

A syndrome of factor VII deficiency and abnormal platelet release reaction

A 15-year-old girl with severe factor VII deficiency and chronic arthropathy showed an excessively prolonged bleeding time. Further studies demonstrated low platelet adhesiveness and abnormal platelet aggregation with ADP, collagen and epinephrine. Release of 14C-serotonin was deficient after aggregation with ADP and epinephrine, but was normal with thrombin. Transfusion of plasma or prothrombin complex concentrate resulted in a partial or complete correction of the bleeding time, respectively, but had no effect on in vitro platelet function tests. Both parents and the only sister had factor VII activities of 42%-72% and factor VII antigen levels of 45%-66% of normal and may thus be heterozygotes with respect to factor VII deficiency. All three had normal bleeding times in spite of abnormal in vitro platelet functions. The observations are interpreted to mean that in this family with factor VII deficiency and abnormal platelet release reaction the platelet abnormality as such was not sufficiently severe to prolong the bleeding time unless the factor VII activity was also very low.

The relationship of platelet coagulant activities to venous thrombosis following hip surgery

Platelets have recently been shown to trigger intrinsic coagulation by two alternative pathways, protect active clotting factors from inactivation by plasma inhibitors and catalyse intrinsic coagulation reactions on the platelet surface to form fibrin. To determine whether these platelet coagulant activities (PCA) might have a role in the pathogenesis of DVT, 29 patients have been studied before and after arthroplasty or other surgery for fractured hip or degenerative hip disease. The occurrence of DVT was detected by [125I]fibrinogen uptake in the legs and confirmed by venography. In patients who developed DVT, all PCA increased progressively and significantly on day 1 (mean rise, 146% of baseline), day 3 (228%) and day 5 (298%) after surgery before isotopic evidence of DVT appeared (mean 3.27 days postoperatively). In patients without DVT no changes in PCA were observed. Plasma coagulation factor assays were no different in patients with a without DVT. Platelet counts and total platelet antiheparin activity increased during the early postoperative period in DVT patients but not in patients without DVT. It is suggested that progressive increases in PCA concerned with triggering and catalysing intrinsic coagulation reactions may play a pathogenetic role in DVT after hip surgery.

Hereditary factor VII and IX deficiencies in a large kindred

A large kindred with combined deficiencies of factors VII and IX is presented. The deficiencies appeared to be independent and the data were not consistent with a diagnosis of haemophilia BM. The identification of mildly affected family members, including carriers of haemophilia B and heterozygotes for factor-VII deficiency, was facilitated by comparison with the 95% confidence interval of an age- and sex-matched control population. The bleeding patterns were those of mild to moderate haemophilia B and did not appear to have been modified by the presence of factor-VII deficiency.