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Summary Background Although predicting the risk of venous thrombosis (VT) in an individual from a family with inherited thrombophilia is of major importance, it is often not feasible. Objectives To develop a simple risk assessment model that improves prediction of the risk of VT for individuals of families with inherited thrombophilia. Patients/methods 1201 relatives from 430 families with inherited thrombophilia (deficiencies of antithrombin, protein C or protein S, and the factor V Leiden and F2 20210A mutations) were recruited at the referral center for thrombophilia in Marseilles, France, from 1986 to 2008. One hundred and twenty-two individuals had a personal history of VT. Sixteen preselected clinical and laboratory variables were used to derive the VT risk score. Results The scores based on the 16 variables and on the five most strongly associated variables performed similarly (areas under receiver operating characteristic curves of 0.85 and 0.83, respectively). For the five-variable score, named the MARNI score, derived from family history score of VT, von Willebrand factor antigen levels, age, severity of thrombophilia, and FGG rs2066865, the risk of VT ranged from 0.2% for individuals with a score of 0 (n = 186) to > 70% for individuals with a score of ≥ 7 (n = 27). The model was validated with an internal bootstrap method. Conclusions With the use of a simple scoring system, assessment of the risk of VT in subjects from families with inherited thrombophilia can be greatly improved. External validation is now needed to replicate these findings.

SummaryFree-TFPI (f-TFPI) presents high anticoagulant activity and its plasma level correlates with unfavorable outcomes in unstable angina. Total TFPI (t-TFPI) represents mainly the lipid-bound form which seems to have a poor anticoagulant activity. Until now, it is not known whether the variations of f-TFPI plasma levels are determined by environmental factors. The aim of our study was to evaluate the influence of cardiovascular risk factors on plasma levels of f-TFPI and relations with other endothelial derived molecules in a population of 626 patients (277 men and 349 women) attending a metabolic ward for primary prevention of coronary disease.Free and total TFPI plasma levels were poorly correlated. f-TFPI levels increased with age in both sexes, t-TFPI in women only. Ageadjusted correlations of TFPI levels with conventional cardiovascular risk factors and endothelial cell markers showed different patterns for f-TFPI and t-TFPI. f-TFPI correlated with parameters associated with insulin resistance, particularly in females. f-TFPI was also positively associated in both genders with fibrinogen and endothelial cell markers: t-PA, thrombomodulin (TM) and von Willebrand factor (vWF). t-TFPI correlated strongly with LDL-C in both sexes. It also correlated negatively with parameters of the insulin resistance syndrome. t-TFPI also correlated with TM but not with other endothelial cell markers. The results of the multivariate step by step analysis showed that cardiovascular risk factors poorly explained the f-TFPI variability (7% and 4% in men and women, respectively), whereas they explained 16 and 20% of t-TFPI variability in men and women respectively (mostly related to LDL-C).In conclusion, this study showed that free- and total-TFPI are regulated differently. f-TFPI strongly correlates with endothelial cell markers and t-TFPI is more related to conventional cardiovascular risk factors. The strong gender effect on f-TFPI levels remains to be explained.

SummaryFive tissue factor reagents and three types of automated instruments for prothrombin time (PT) determination were studied in an international multicenter collaborative exercise. The purpose of this work was to determine the international sensitivity index (ISI) for each combination of reagent and instrument against the international reference preparation RBT/90. Each type of instrument was used by 3 or 4 centers to assess the interlaboratory variation of the ISI. The interlaboratory variation of the ISI for each combination of reagent and instrument ranged between 0.4% and 7.8% coefficient of variation. For three reagents, the mean ISI values for ACL (nephelometric) and STA (mechanical) were practically identical, but the mean ISI values for MLA (photo-optical) were at least 10% higher. For two other reagents prepared from rabbit tissue, the mean ISI values increased in the order ACL, STA, MLA. The widest range of mean ISI values was noted with one rabbit tissue factor reagent: 1.68 for ACL and 2.00 for MLA. Exclusion of patient specimens with INR 4.5 determined by the international reference preparation resulted in a slight decrease of the mean ISI.The interlaboratory variation of the International Normalized Ratio (INR) was assessed from the results obtained with common lyophilized and deep-frozen plasmas. The use of instrument-specific ISI values resulted in reduced interlaboratory variation of the INR. It is recommended that thromboplastin manufacturers provide instrument-specific ISI values.

SummaryThe interlaboratory variation of the International Normalized Ratio (INR) in various external quality assessment schemes is still relatively high. This is partly caused by inaccuracy of manufacturers’ stated International Sensitivity Index (ISI) and/or local instrumentation effects. The interlaboratory variation and accuracy of INR determinations may be improved by a local calibration procedure based on lyophilized plasmas with assigned INRs. The purpose of the present study was to determine INR values for different types of lyophilized plasmas to be used for local calibration. A total of 13 lyophilized plasmas (one normal, six from coumarin-treated patients, six artificially depleted) were analyzed by 10 laboratories, each using five calibrated prothrombin time (PT) systems. INRs were calculated for each plasma using each laboratory’s specific ISI and mean normal prothrombin time values. In the same way, five deep-frozen pooled plasmas from coumarin-treated patients were analyzed. There were significant INR differences for the lyophilized plasmas between the prothrombin time systems. The differences were relatively small for the deep-frozen coumarin plasmas (CV 2.6-3.3%) and three lyophilized coumarin plasmas from one manufacturer (CV 3.7-4.8%). Important INR differences were observed for three lyophilized coumarin plasmas from another manufacturer (CV 9.5-14.1%) and several artificially depleted plasmas (CV 5.3-12.8%). The citrate concentrations in the artificially depleted plasmas were lower than those in the normal and coumarin plasmas. These differences should be considered in the selection and certification of plasmas as calibrants for local calibration of PT systems. The lyophilized plasmas’ INR values obtained in the present study will be used for a field study of local PT calibration to assess their efficacy.

SummaryThe contribution of coagulation factors and fibrinolytic variables to the development of ischaemic arterial disease is still not clearly established. The PRIME study is a prospective cohort study of myocardial infarction in men aged 50-59 years and recruited from three MONICA field centers in France (Lille, Strasbourg and Toulouse) and the center in Northern Ireland (Belfast). Baseline examination included measurement of plasma fibrinogen, factor VII, and PAI-1 activity in over 10,500 participants. We investigated the associations of these haemo-static variables with cardiovascular risk factors, prevalent atherosclerotic disease and geographical area. Fibrinogen level increased with age, smoking, waist-to-hip ratio, LDL-cholesterol, and it decreased with educational level, leisure physical activity, alcohol intake and HDL-cholesterol. Factor VII activity increased with body mass index, waist-to-hip ratio, triglycerides, HDL- and LDL-cholesterol. PAI-1 activity increased with body mass index, waist-to-hip ratio, triglycerides, alcohol intake, smoking, and decreased with leisure physical activity. PAI-1 level was higher in diabetic subjects than in subjects without diabetes. Cardiovascular risk factors explained 8%, 9%, and 26% of the total variance in fibrinogen, factor VII, and PAI-1, respectively. Compared with participants without prevalent cardiovascular disease, those with previous myocardial infarction (n = 280), angina pectoris (n = 230), or peripheral vascular disease (n = 19) had significantly higher levels of fibrinogen, but those with stroke (n = 67) had not. PAI-1 activity showed a similar pattern of association. The odds ratio for cardiovascular disease associated with a rise of a one standard deviation in fibrinogen and PAI-1 was 1.31 (95% confidence interval: 1.20 to 1.42, p

Contexte Nous rapportons la demarche diagnostique d’un syndrome hemorragique chez une fille âgee de 6 ans. Observation Une fillette de 6 ans est hospitalisee pour volumineux hematome traumatique (torsion de l’avant bras par jeu). Elle n’a pas d’antecedent hemorragique, mais l’anamnese ne revele aucune situation a haut risque. Elle est la 3eme enfant d’une fratrie de 3 et n’a pas d’antecedent hemorragique familial. Il n’y a pas de notion de consanguinite. Les parents separes de l’enfant sont en conflit ouvert et le pere gardait sa fille les jours precedant l’hospitalisation. La mere a un comportement difficile vis-a-vis du personnel. Elle s’oppose a toute intervention de la psychologue aupres de son enfant agitee. L’examen clinique est normal en dehors de l’hematome. Il n’y a ni syndrome tumoral, ni symptomatologie infectieuse. Quels examens de depart ? Plaquettes a 386 G/L ; Hb a 112 g/L ; Leucocytes a 10,6 G/L sans cellule pathologique ; TP a 36 % ; TCA et TCK > 150s ; TT > 60s ; fibrinogene a 2,56 g/l ; taux de facteurs II, VII et X diminues respectivement a 48 %, 54 % et 21 % avec FV et bilan hepatique normaux ; taux de FVIII normal (126 %), taux de FIX, FXI et FXII diminues respectivement a 35 %, 55 % et 28 % ; monomeres de fibrine et D-Dimeres negatifs. L’hypothese de CIVD est eliminee Quelles hypotheses, donnees complementaires d’interrogatoire et explorations ? Il n’y pas de notion de prise medicamenteuse (ni AVK, ni nouvel anticoagulant oral, ni heparine) ; pas de prise de substance heparine-like, pas de morsure ou piqure d’insecte. L’activite anti-Xa (heparine) est fortement positive a 1,54 UI/ml, mais l’ajout de sulfate de protamine in vivo et in vitro est sans effet. La supplementation en vitamine K per os puis IV ne modifie pas les resultats obtenus. Les hypotheses d’intoxication, empoisonnement ou envenimation sont eliminees. Quelles autres hypotheses ? On suppose la presence d’un anticoagulant circulant (ACC) puissant. Cependant, la recherche d’ACC est negative en dRVVT. Le TT sur melange reste allonge. Le diagnostic ? La generation de thrombine est a peine detectable. L’hypothese d’un inhibiteur puissant dirige contre la thrombine est evoquee devant la perturbation majeure de tous les temps de la coagulation qui detectent la formation de thrombine (TP, TCA, TT). Les 2 grandes hypotheses sont alors une cause constitutionnelle avec l’existence d’un variant antithrombine (variant Pittsburgh de l’alpha 1 antitrypsine) ou une cause acquise avec presence d’un anticorps puissant. Dans le serum, l’electrophorese des proteines revele un pic supplementaire en zone des α2-globulines, et l’immunofixation avec anticorps anti-α1-AT montre la presence de deux bandes distinctes. Le sequencage direct du gene de l’α1-AT retrouve la mutation Met 382 > Arg, en position c.1145T > G du gene, a l’etat heterozygote (ancienne nomenclature : Met358 > Arg). Ainsi le diagnostic d’une maladie hemorragique constitutionnelle rare est retenu. Conclusion Le variant Pittsburgh de l’α1-antitrypsine (α1-AT) ou « antithrombine Pittsburgh » resulte d’une substitution Met 358 > Arg sur le site reactif de l’α1-AT, lui conferant une activite antithrombine drastique. Ce variant rare, rapporte dans la litterature chez 4 patients, s’accompagne d’un syndrome hemorragique d’intensite variable.

SummaryWe analyzed the clinical features of 36 patients homozygous for the Arg 506 to Gin factor V mutation and found a circumstantial event at risk for thrombosis in 29 of the 31 patients with thrombosis. The most frequent predisposing factors were the post-partum period and the use of oral contraceptives in women, and surgery in both sexes. Venous thrombosis recurred in 48% of the patients. One patient had a myocardial infarction at age 33 years, and also had an antiphospholipid syndrome. Homozygous Gin 506 mutation leads to far less severe thrombotic complications than homozygous protein C and protein S deficiencies and does not seem to predispose patients to arterial thrombosis.

The levels of anti-human and anti-porcine factor VIII inhibitors, measured in 63 severe haemophilia A patients, lay in the ranges of < 0.2-2,600 and < 0.2-1,300 Bethesda units per ml (BU/ml), respectively, with a median cross-reactivity of 33%. In 4 patients, human and porcine inhibitor levels were determined using both plasma, either human or porcine, and factor VIII concentrate, either very high purity human or porcine (Hyate:C). A good correlation between titres was found, whatever the source of factor VIII (plasma or concentrate). The cross-reactivity varies from 0 to over 100%, indicating that the evaluation of both human and porcine inhibitors should be mandatory before any treatment with Hyate:C. Results show that of the 46 patients with human inhibitor of more than 5 BU/ml, 21 (46%) with a low porcine inhibitor (< 5 BU/ml) could benefit from Hyate:C.

Among diabetic patients the presence of a nephropathy is associated with an increased risk of cardiovascular disease. But the prevalence and importance of the classical risk factors of cardiovascular disease among these patients do not appear to fully explain this phenomenon. An impaired fibrinolysis has been shown to be a risk factor for coronary heart disease. Therefore we have studied the fibrinolysis parameters in 31 insulin dependent diabetic patients subdivided in three groups according to their urinary albumin excretion (UAE), in normal (11 patients with UAE

SummaryThe mechanism underlying diurnal variations in PAI-1 as well as the cellular origin of PAI-1 in subjects with high PAI-1 levels are unknown. We evaluated diurnal changes (8:00 am vs 4:00 pm) in PAI-1 (functional and immunological assays), t-PA Ag and t-PA/PAI-1 complex levels in controls and subjects with high PAI-1 levels. Three test groups were recruited among obese hyperinsulinmic subjects, emergency care unit patients with inflammatory syndrome or infection and pregnant women.The classical afternoon decrease of PAI-1 level was observed in controls and obese subjects but its amplitude was greater in the latter. The decrease in t-PA Ag and t-PA/PAI-1 complex levels was the same in controls and in obese. As, in previous studies, elevated PAI-1 levels have been correlated with insulin resistance and a decrease in insulin sensibility has been described in the early morning, it is proposed that this “dawn phenomenon” could be implicated in the circadian variations of PAI-1 in controls and could be amplified in obese subjects. Great variability in PAI-1, t-PA Ag or t-PA/PAI-1 complex levels was observed in patients with acute inflammatory syndrome or infection for whom classical biorhythms are suppressed. No diurnal changes in PAI-1 and other fibrinolytic parameters were observed in patients with inflammatory syndrome or in pregnant women suggesting that other sources and/or other regulatory mechanisms of PAI-1 production are involved.

In 100 consecutive patients with clinically suspected deep vein thrombosis (DVT) of the legs, plasma D-dimer measurements based on an enzyme linked immunosorbent assay (ELISA) and on latex agglutination (Diagnostica Stago) were compared to the results of real time B mode ultrasound imaging combined with Doppler examination, which in a previous study has proved to be a very accurate method competitive with venography for the diagnosis of DVT. Forty five patients had DVT identified with the ultrasonic tests. We have obtained for ELISA and latex tests of D-dimer respectively: accuracy: 60%, 56%; sensitivity: 98%, 98%; specificity: 29%, 22%; predictive value of a positive test: 53%, 50% and predictive value of a negative test: 94%, 92%. These results confirmed those of previous studies using ELISA or latex assays, with venography as a reference test. We conclude that a negative D-dimer test, defined by a value lower than 0.5 μg/ml, excludes the diagnosis of DVT in 94% of cases by ELISA method and in 92% of cases by latex method. A reduction of venography or other objective testing of the venous circulation could be obtained if these methods were not performed in the case of a negative D-dimer test. However the safety of withholding anticoagulant therapy in out patients with negative tests needs confirmation in a prospective trial.

The effectiveness and safety of a very low molecular weight heparin fraction were evaluated in the prevention of deep-vein thrombosis in patients confined to bed due to hemiplegia consecutive to a recent cerebral infarction. CY 222 was administered within 48 hours of the stroke by one single daily subcutaneous injection of 0.6 ml (= 15,000 U AXa IC) during 14 days. This randomized pilot study involved 30 patients. The effects of CY 222 were assessed in a group of 15 patients compared with a control group of 15 untreated patients. No deep-vein thrombosis was detected by the labelled fibrinogen test in the treated group, as against 12 patients in the control group. Six patients (3 in each group) died during the study. One case of lethal pulmonary embolism was observed and confirmed at autopsy in the control group. In the remaining 5 patients, no systematic autopsy which would have asserted the absence of pulmonary embolism or drug-induced haemorrhage was performed. Numerous standard laboratory tests confirmed that CY 222 was well tolerated.

SummaryCongenital deficiencies of protein S (PS) are associated with thrombophilia. Their characterization and classification have been hampered by the complex physiology of the protein C-protein S system and the poor standardization and reliability of laboratory assays. The free active form of protein S is usually determined by immunoassay using polyclonal antibodies in the plasma supemate after polyethyleneglycol (PEG) precipitation. A new one step ELISA using two monoclonal antibodies specific for distinct epitopes of the free form of protein S has been developed for the direct measurement of free PS in untreated plasma.We have tested two ELISA assays for free PS. One assay was based on the PEG precipitation (Asserachrom PS®, Stago, Asnières, France) whereas the other was a one step ELISA assay (Asserachrom® free PS, Stago). Values were obtained in 35 PS deficient patients recruited among 500 consecutive patients evaluated by the laboratory for diagnosis of congenital disorders of coagulation. Values were compared to those obtained in 50 patients with no PS deficiency matched for age and sex with the PS deficient patients as well as in 33 normal subjects and in 12 pregnant women. Strong correlation was found between the two tests (r = 0.81, p

We investigated whether haemostatic variables were related with dietary fatty acid composition as estimated by the fatty acid content of erythrocytes. Subjects were a subsample (n=283) of the participants in the Prospective Epidemiological Study of Myocardial Infarction (PRIME) Study. Factor VII, fibrinogen, tissue-type plasminogen activator antigen (tPA-ag), plasminogen activator inhibitor type 1 (PAI-1), D-dimer and von Willebrand factor (vWf) were measured and the fatty acid composition was determined in the phospholipids of total erythrocytes by gas chromatography. Statistical analyses were performed using multiple linear regression analyses with adjustment for age, center and body mass index. tPA-ag was significantly related to the n-3 fatty acids derived from fish. This was reflected in an inverse association of all n-3 fatty acids combined with tPA-ag (beta=-0.37 ng/ml/%, 95% confidence intervals: -0.45, -0.29, P.01). Positive and significant associations of D-dimer with arachidic and eicosamonoenoic acid were observed (P.01). No relationships were found between fatty acids and fibrinogen, vWf, PAI-1 or factor VII. The results of this study suggest that consumption of n-3 fatty acids derived from fish may favourably influence tPA-ag.

Abstract —Identification of combined genetic factors in factor V Leiden carriers is important for a more accurate risk assessment for venous thrombosis (VT). Among these individuals, we evaluated the role of polymorphisms of the plasminogen activator inhibitor-1 (PAI-1) gene in the thrombophilic phenotype. A total of 382 factor V Leiden carriers were included in the study. This population was divided into 3 groups. Group 1 (n=168) included individuals with a personal history of VT; group 2 (n=140) included individuals without personal VT but with a familial history of VT; and group 3 (n=74) included individuals without VT and with a fortuitous discovery of the factor V Leiden mutation. We compared the genotype distribution of 2 polymorphisms, A −844G and −675 4G/5G, located in the promoter region of the PAI-1 gene among these 3 groups of individuals. The A −844G allele frequency differed significantly among the 3 groups ( P =0.048), the A allele being more frequent in patients who suffered from VT (61%) than in subjects without VT (52%, P =0.015), whereas no difference was observed between the 2 groups of asymptomatic individuals. The prevalence of genotype AA carriers was higher in patients with VT (38%) than in asymptomatic individuals (21%, P =0.015), leading to an odds ratio of 1.74 (95% confidence interval, 1.3 to 3.8). Carrying the AA genotype conferred a risk of deep VT of 2.08 (95% confidence interval, 1.28 to 3.40), whereas it did not seem to significantly influence the risk of pulmonary embolism. Concerning the −675 4G/5G polymorphism, no significant difference was observed among the 3 groups, the 4G allele frequency being 0.54 (in group 1), 0.49 (in group 2), and 0.45 (in group 3). These data suggest a role for the −A844G PAI-1 gene polymorphism in the thrombophilic phenotype of factor V Leiden carriers.

Abstract —Increased plasma plasminogen activator inhibitor-1 (PAI-1) concentration has been identified as a risk factor for coronary heart disease. We investigated the relative contribution of both metabolic factors involved in the insulin resistance (IR) syndrome and polymorphisms of the PAI-1 gene to plasma levels of PAI-1 in 228 healthy nuclear white families from the Stanislas Cohort. Variables related to IR included body mass index, waist-to-hip ratio, fasting insulin, triglyceride, and HDL cholesterol. Five PAI-1 gene polymorphisms were studied, including a newly described G+12078A substitution in the 3′ region. A sex difference was observed, with fathers exhibiting higher IR state and PAI-1 levels and stronger correlations between PAI-1 and IR variables than mothers. Such a difference was not observed in offspring. Family correlations were of similar magnitude for fibrinolytic parameters and IR variables. The PAI-1 genotypes A−844G, −675 4G/5G, and G+12078A polymorphisms, which were in strong linkage disequilibrium, were associated with plasma PAI-1 levels. In multivariate analysis, IR explained a major part of PAI-1 variability (49% in fathers, 29% in mothers), whereas polymorphisms had only a minor contribution, explaining 3% of variability in women and having no significant effect in men. We conclude that plasma levels of PAI-1 are, in a healthy population, primarily determined by the IR syndrome, this relationship being stronger in males. The contribution of the PAI-1 gene seems larger in females. These results deserve special attention for understanding the relationships observed between fibrinolytic parameters and the risk of developing a cardiovascular ischemic event.

Ala147Thr and C+1542G Polymorphisms in the TAFI Gene Are not Asssociated with a Higher Risk of Venous Thrombosis in FV Leiden Carriers

A Three-generation Family Presenting Five Cases of Homozygosity for the 20210 G to A Prothrombin Variant

Several mechanisms have been proposed to explain thrombotic tendency in Behçet's syndrome. We report the case of a 43-year old woman presenting retinal-vein thrombosis, factor XII deficiency and Behçet's syndrome. This kind of association has thus far never been reported. Factor XII deficiency is known to possibly induce various types of thrombosis and might explain the prevalence of ocular symptoms in our patient.

Thrombomodulin is a natural anticoagulant present on endothelial cell membrane. A soluble form exists in plasma and is a molecular marker reflecting injury of endothelial celles. Using a new ELISA method, we investigated plasma thrombomodulin in 45 systemic lupus erythematosus patients. The level of thrombomodulin was significantly increased when anti-phospholid antibodies were present, suggesting a pathogenetic role of those antibodies on vascular endothelium in vivo.

Thirty patients with deep venous thrombosis (DVT) (less than 7 days) were randomised into three treatment groups and received Choay's CY222 at the respective doses of 4 mg (group I), 3 mg (group II) and 2 mg/kg/24 h (group III) administered in three subcutaneous injections. A relationship between the thrombolytic effect evaluated on phlebography and plasma fibrinolysis parameters was looked for. Phlebography was performed before (D0) and on Day 7 (D7) of treatment and scored by Marder's index (MI). The mean decrease in MI on D7 was 40%. Blood samples were taken at DO and at 8.00 am before injection on D1, D3, D5 and D7. The following fibrinolysis parameters: euglobulin fibrinolytic activity (EFA), t-PA-Ag, PA inhibitor (PAI), showed no change during treatment in each group. Among patients with MI > 10 on DO (n=24) two response groups, A and B, were distinguished, based upon the thrombolytic response: Group A — six patients (three in treatment group I, two in group II and one in group III) with high degree of thrombolysis (decrease in MI ⩾ 80%); Group B — nine patients (three in each treatment group) with no thrombolytic response (decrease in MI ⩽ 20%). Changes in plasma fibrinolysis parameters in Groups A and B showed no difference during treatment. On DO mean PAI was lower in Group A than in Group B (p 4 U/ml) (5 of 30) before and during treatment were in Group B. These results show that CY222 is effective in the treatment of DVT. Its mechanism of action remains unclear, as no direct effect on EFA, t-PA-Ag, and PAI level could be demonstrated. No thrombolysis occured in patients with high PAI before treatment. Thus pre-treatment determination of PAI could have a predictive value in the efficacy of CY222 treatment.

SummaryThe fibrinolytic system was investigated in 120 patients with spontaneous or recurrent deep vein thrombosis (DVT) without any known organic disease able to explain by itself the occurrence of a thrombosis and without any known defect of antithrombin III, Heparin Cofactor II, Protein C, or Protein S. The assays included: Euglobulin fibrinolytic activity (EFA), tissue-type plasminogen activator related antigen (t-PA-Ag) and plasminogen activator inhibitor activity (PA inhibitor), which were measured before and after 10 min of venous occlusion (V. O.). On the basis of the results, the patients could be classified in 3 groups:good responders with an at least two-fold increase of EFA after venous occlusion (n = 76), poor responders with a lesser increase of EFA due to deficient release of t-PA (n = 12), and poor responders with a normal t-PA release but an increased level of PA-Inhibitor (n = 32).The poor responders due to deficient t-PA release (10% of total) had a higher incidence of recurrence of deep vein thrombosis, than the other groups (p It is concluded that a poor fibrinolytic response to venous occlusion occurs in 35 percent of DVT patients. Poor responders however fall into two categories, one fourth with deficient t-PA release who have a high risk for recurrent venous thrombosis, and three fourth with increased PA-Inhibitor levels which may be associated with underlying diseases also causing hypertriglyceridemia. Further elucidation of the correlation between recurrent venous thrombosis and deficient fibrinolysis is expected to result in more specific and adequate treatment and prevention of DVT.

SummaryElderly patients have previously been shown to have an increased plasma concentration of tissue plasminogen activator (t-PA) antigen (t-PAAg). Since the concentration of t-PA Ag dependson both free t-PA and t-PA complexed with inhibitors, mainly plasminogen activator inhibitor (PA inhibitor), we have investigated the relationship between the plasma concentration of PA inhibitor and age in 20 elderly and 20 young individuals. Elderly individuals showed a slight increase in PA inhibitor, in parallel with increase on others, acute-phase proteins, fibrinogen, von Willebrand factor, factor VIII :C, and the erythrocyte sedimentation rate. The increase i PA inhibitor as well as other acute-phase proteins in the elderly may be significant in relation to the increased incidence of thrombotic disease.

Positive-pressure and initial-flow-rate (Hémorhéomètre) filtration systems were used to study the deformability of erythrocytes from whole blood stored in EDTA or heparin. When all contaminating platelets and leucocytes were removed from the erythrocyte suspension there was no significant anticoagulant effect on erythrocyte filtration. Blood may therefore be stored in K2EDTA (1.5 mg/ml blood) or lithium heparin (15 IU/ml blood) for up to 6 hours at room temperature prior to measurement of erythrocyte filterability.

Rapid inhibition of tissue-type plasminogen activator (t-PA) in human plasma was measured by addition of 5 IU (50 ng) of purified t-PA per ml plasma and measurement of residual t-PA in the euglobulin precipitate after 5 min incubation at 37°C. The recovery of both t-PA activity and t-PA related antigen in pooled plasma from healthy individuals was approximately 90 percent, indicating that one ml of pooled normal plasma inhibits less than 1 IU or 10 ng of t-PA within 5 min. Of 20 control subjects 13 had less than 1 IU inhibitor activity; 5 subjects inhibited between 1 and 3 IU of t-PA and 2 subjects inhibited around 4.5 IU. The inhibitor titer in the latter two had however decreased to 1.8 and 2.7 IU after two days. Markedly increased rapid inhibition of t-PA (> 4 IU per ml) was found in plasma of patients with severe liver disease (3 of 8), pancreatitis (4 of 8), malignancy (5 of 26), but only very occasionally and transiently in that of patients with myocardial infarction (5 of 28) or deep vein thrombosis (2 of 9). Increased inhibition was observed on the first day following coronary bypass (22 of 42) or open heart (16 of 27) surgery but this had disappeared in 15 of 16 patients on the fifth postoperative day. Titration of inhibitor levels revealed maximal amounts of 30 to 50 IU per ml plasma. Gel filtration revealed that inhibition of t-PA was associated with a shift in the elution position of t-PA related antigen from an apparent molecular weight of 70,000 to 120,000. A positive correlation was found between inhibition of t-PA and of urokinase (r=0.82), but not between the t-PA inhibition level and the t-PA antigen concentration in plasma (r=0.46). These findings are compatible with the interpretation that human plasma contains a rapidly acting inhibitor of t-PA and urokinase with an apparent molecular weight of approximately 50,000. Its concentration in healthy individuals is usually less than 10 ng per ml but may increase up to 50-fold in severely ill patients or after major surgery.

SummaryIt has been reported that the level of PA-inhibitor increases in postoperative patients and on the other hand that glucocorticoids increase the PA-inhibitor level in cell culture. Because surgery is associated with increased plasma cortisol level, a relation between the postoperative increase in plasma cortisol and PA-inhibitor levels was looked for.Blood samples were collected from 8 patients undergoing extensive abdominal surgery, before operation and postoperatively at 2 hr, 4 hr, 24 hr and daily for 7 days. Plasma cortisol and PA-inhibitor were increased 2 hr after surgery, when there was a significant correlation (p In 7 controls 0.25 mg ACTH was given intravenously and blood was collected after ½, 1, 2, 4, 6 hr. Although the increase in plasma cortisol level following ACTH was comparable to that observed after surgery the increase was not associated with significant change in PA-inhibitor level, t-PA R: Ag or EFA.A cause-effect relationship between the increased plasma cortisol and PA-inhibitor level could not be shown. The mechanism of the postoperative increase in PA-inhibitor thus remains unknown.

SummaryWe have previously demonstrated that a short period of normoglycaemia obtained through an artificial pancreas in uncontrolled insulin-dependent diabetics improves parameters of the functional microangiopathy such as erythrocyte deformability and platelet aggregation. Because recently an immunoradiometric assay for tissue plasminogen activator (t-PA) was developed we measured t-PA levels in 18 uncontrolled insulin-dependent diabetics before and after 24 hr of normoglycaemia induced by insulin to look for a modification of endothelial cells function. After 24 hr of strict control, plasma free insulin levels rose significantly, total t-PA R-Ag, its active fibrin binding fraction and euglobulin fibrinolytic activity were significantly decreased. These results suggest a responsibility for insulin in the decrease in t-PA blood level and could explain at least partially the relation between hyperinsulinism, thrombosis and atherogenesis.