Met 358 to Arg mutation of alpha 1-antitrypsin associated with protein C deficiency in a patient with mild bleeding tendency.

The molecular defect responsible for a dramatic prolongation of all standard clotting tests discovered in a 15-yr-old boy has been identified. Initial investigations revealed the presence of an activated Factor X (Factor Xa) and thrombin inhibitor which copurified with alpha 1-antitrypsin (alpha 1-AT), thereby suggesting the occurrence of an alpha 1-AT variant similar to alpha 1-AT Pittsburgh. This was confirmed by dot-blot analysis and direct sequencing after amplification by the polymerase chain reaction. A G to T transition at nucleotide 10038 results in the substitution of Met to an Arg, converting alpha 1-AT into an Arg-Ser protease inhibitor (serpin) that inhibited thrombin and Factor Xa more effectively than antithrombin III. Surprisingly, there was no bleeding history in the proband. The common mutation Z, which may explain a reduced expression of the allele bearing the Arg 358 Met mutation, was not observed in the propositus' DNA. To exclude the presence of another mutation, the coding regions and intron/exon junctions were sequenced. No other mutation was found. Recently, the patient experienced his first hemorrhagic episode at the age of 17. The level of the abnormal inhibitor had increased twofold 2 mo before. The large decrease in protein C concentration may account for the mild bleeding tendency in this case, despite the presence of the alpha 1-AT Pittsburgh mutation. An abnormal protein C pattern was observed in patient's plasma, suggesting that the circulating deficiency might be due to a deleterious effect of the abnormal inhibitor on both intracellular processing and catabolism of protein C.

Molecular characterization of antithrombin III (ATIII) variants using polymerase chain reaction. Identification of the ATIII Charleville as an Ala 384 Pro mutation.

The genes of seven structural mutants of antithrombin III (ATIII), presenting either defective serine protease reactivity or abnormal heparin binding, were analyzed. The polymerase chain reaction (PCR) was used to amplify the corresponding gene exon and the mutation was identified by either dot blot analysis using a battery of allele-specific oligonucleotide probes or sequencing. Variants Paris and Paris 2 were identified as Arg 47 Cys mutations, and Clichy, Clichy 2, and Franconville were found to be Pro 41 Leu mutations. All five are heparin binding-site variants. ATIII Avranches is an Arg 393 His mutation and ATIII Charleville is an Ala 384 Pro mutation. These two mutations impair the reactive site of the molecule. ATIII Charleville is a new mutation of the reactive center, as predicted by previous biochemical data. The position of this new mutation, together with the other previously described mutations of the reactive center, sheds light on the molecular function of this site in inhibiting thrombin. Finally, genomic amplification by PCR is a powerful technique for the fast identification of antithrombin III mutations and their homozygous/heterozygous status, and should be useful for predicting thrombotic risk.

[Endovascular repair of a tuberculous aortic false aneurysm]. / Traitement par voie endovasculaire d'un faux anévrisme tuberculeux de l'isthme aortique.

INTRODUCTION: Aortic aneurysms are a well known but rare complication of tuberculosis. Their major complication is aneurysmal rupture, unforeseeable and lethal. EXEGESIS: Chest pain and hemoptoic expectoration revealed a false aneurysm of the aortic isthmus in a 48-year-old man. Endovascular repair with a stent graft was urgently undertaken. Tuberculosis was diagnosed 6 weeks thereafter by the growth of gastric juice cultures and medically treated. Most tuberculous aortic aneurysms are false aneurysms, caused by an adjacent tuberculous focus eroding the aortic wall. They present with pain, bleeding or as para-aortic masses. CONCLUSION: Tuberculous false aneurysms of the aorta necessitate an early intervention before they rupture. Surgical treatment remains the preferred option but endovascular repair with a stent graft is a therapeutic alternative, to be considered in high-risk surgical patients.

Oral Beraprost sodium, a prostaglandin I(2) analogue, for intermittent claudication: a double-blind, randomized, multicenter controlled trial. Beraprost et Claudication Intermittente (BERCI) Research Group.

BACKGROUND: Beraprost sodium (BPS) is a new stable, orally active prostaglandin I(2) analogue with antiplatelet and vasodilating properties. We report the results of a phase III clinical trial of BPS in patients with intermittent claudication. METHODS AND RESULTS: Patients (n=549) with a pain-free walking distance of between 50 and 300 m were entered into a 4-week single-blind placebo run-in phase. Patients whose pain-free walking distance had changed by <25% were then randomized to receive either BPS (40 microg TID, n=209) or placebo (n=213) in a double-blind manner for 6 months. Pain-free and maximum walking distances were measured on the occasion of treadmill exercise tests performed at baseline and 1.5, 3, 4.5, and 6 months after randomization. Success was defined as an improvement of >50% in pain-free walking distance at month 6 and in > or =1 earlier treadmill exercise test in the absence of critical cardiovascular events. Success was observed more frequently in the BPS group (43.5%) than in the placebo group (33.3%, P=0.036). Pain-free walking distances increased by 81.5% and 52.5%, respectively, in the BPS and placebo groups (P=0.001) and maximum walking distances by 60.1% and 35.0%, respectively (P=0.004). The incidence of critical cardiovascular events was 4.8% in the BPS group and 8.9% in the placebo group. CONCLUSIONS: These results show that BPS is an effective symptomatic treatment of patients with intermittent claudication. The beneficial effects of BPS on critical cardiovascular events should be confirmed in appropriate clinical trials.

The specific thromboxane receptor antagonist S18886: pharmacokinetic and pharmacodynamic studies.

OBJECTIVES AND PATIENTS: We conducted a multicenter double-blind pharmacokinetic/pharmacodynamic (PK/PD) study of the new oral thromboxane receptor antagonist S18886 in 30 patients with peripheral artery disease, who were randomized to receive five different oral dosages of S18886 (1, 2.5, 5, 10 or 30 mg) for 12 weeks (83 days). Primary objective was to determine the effect of S18886 on platelet aggregation ex vivo. RESULTS: Pharmacokinetics of S18886 was linear, with peak plasma levels being reached between 30 min and 2 h and a terminal half-life of 5.8-10 h. No significant accumulation of S18886 in plasma was observed after repeated dosing. The relationship between the S18886 concentration and platelet inhibition was examined in terms of U46619-induced platelet aggregation. Over the range of doses studied, there was a predictable relation between the plasma drug concentration and the degree of platelet inhibition at each dose. Maximal inhibition of U46619-induced platelet aggregation was achieved within 1 h with all oral doses of S18886, and this effect was maintained for at least 12 h. The PK/PD relationship was direct, and U46619-induced platelet aggregation was strongly inhibited by S18886 plasma concentrations above 10 ng mL(-1). This concentration was thus the minimal effective antiplatelet level in this population, and was maintained only by the dosages of 10 and 30 mg. The safety profile of S18886 was excellent, whatever the unit dose, with no attributable adverse events. CONCLUSION: The results of this study, which included modeling and simulation, help identify the minimal effective plasma concentration of S18886 required for potent antiplatelet efficacy in patients with stable peripheral arterial disease.

Hypercoagulable states in primary upper-extremity deep vein thrombosis.

BACKGROUND: There are very few data on the prevalence of coagulation abnormalities in primary deep vein thrombosis of the upper limbs. OBJECTIVE: To determine if coagulation abnormalities play a role in effort-related and/or idiopathic (non-effort-related) upper-extremity deep vein thrombosis (UEDVT). METHODS: Fifty-one consecutive patients (21 men and 30 women) who had effort-related (n = 20) or idiopathic (n = 31) UEDVT over an 18-year period (median age at diagnosis, 32 years; age range, 15-86 years) were routinely reexamined. Plasma was screened for antithrombin, protein C, and protein S deficiencies and for antiphospholipid antibodies (lupus anticoagulant and anticardiolipin antibodies). The DNA was screened for factor V Leiden and for prothrombin gene G20210A mutations. RESULTS: The median age (35 vs. 28 years), the proportion of women (81% [25/31] vs. 25% [5/201), the proportion of patients with a personal and/or family history of thromboembolism (42% [13/31] vs. 15% [3/20]), and the proportion of patients with at least 1 coagulation abnormality (42% [13/31] vs. 15% [3/20]) were higher in the idiopathic UEDVT group than in the effort-related UEDVT group. The odds ratio of having a coagulation abnormality was 4.09 (95% confidence interval, 0.99-16.78; P = .06) in the idiopathic UEDVT group compared with the effort-related UEDVT group. CONCLUSION: Hypercoagulable states appear to play a significant role in idiopathic but not in effort-related UEDVT.

The factor II G20210A gene polymorphism, but not factor V Arg506Gln, is associated with peripheral arterial disease: results of a case-control study.

BACKGROUND: The FIIG20210A polymorphism has been associated with arterial wall thickness and atherothrombotic diseases in selected subgroups. The FVArg506Gln polymorphism does not seem to be associated with arterial diseases. Few data are available on these polymorphisms and the risk of peripheral arterial disease (PAD). OBJECTIVES: To study the association between the FIIG20210A and FVArg506Gln polymorphisms and PAD and its clinical severity. To examine the potential interactions with traditional vascular risk factors. PATIENTS AND METHODS: We studied 184 consecutive male patients under 70 years of age with symptomatic PAD and 330 age-matched male controls free of symptomatic PAD and with no cardiovascular history. We evaluated the FIIG20210A and FVArg506Gln polymorphisms in all subjects. RESULTS: Mean age was 57.1 +/- 7.2 years (cases) and 56.7 +/- 7.6 years (controls). The FII20210A allele was more frequent in PAD patients with odds ratios (OR) of 3.77 (1.39-10.2) in univariate analysis and 4.30 (1.3-14.7) after adjustment for diabetes, smoking, hypertension and hypercholesterolemia. In smokers or past smokers the magnitude of the association was markedly increased but there was no evidence of an interaction between tobacco exposure and FIIG20210A. In case subjects, the FII20210A allele was also associated with critical ischemia [OR = 4.1 (1.1-15.7), P = 0.039 in multivariate analysis]. FVArg506Gln was not associated with PAD [OR = 0.65 (0.27-1.54) and 0.77 (0.28-2.1) in univariate and multivariate analyses, respectively]. CONCLUSIONS: The FIIG20210A gene polymorphism may be a risk factor for PAD and its severity. In contrast, the FVArg506Gln polymorphism is not associated with PAD.

Incidence and prognosis of cancer associated with bilateral venous thrombosis: a prospective study of 103 patients.

BACKGROUND: A strong association between bilateral deep vein thrombosis (DVT) and cancer had been found in one retrospective study. To confirm this finding, consecutive patients with an objective diagnosis of bilateral DVT were followed over 12 months. PATIENTS AND METHODS: One-hundred and three patients, hospitalized for bilateral DVT, were included in the study. Twenty-six patients (25.2%) were already known to have a cancer, 26 (25.2%) had a previous history of venous thromboembolic disease, 44 (42.7%) had a symptomatic pulmonary embolism. The patients were scheduled to be prospectively followed up at 3, 6 and 12 months as outpatients. Information on recurrence, evidence of a new overt cancer and the cause of death were recorded for all patients. RESULTS: A new cancer was diagnosed in 20 (26%) of the 77 patients without known cancer at admission. The risk of cancer was significantly more important in idiopathic thrombosis than in patients with secondary thrombosis (40.5% vs. 12.5%; odds ratio 4.8, 95% confidence interval 1.4, 18.8). Seventy percent of the cancers discovered had already spread. Age, gender, presence of pulmonary embolism, recurrence and location of the thrombosis were not statistically associated with the risk of cancer. The 1-year survival rates of patients with a previously known cancer and patients with a newly discovered cancer were, respectively, 26% and 35% (P = 0.33). CONCLUSIONS: Bilateral DVT is a significant risk indicator of malignancy. Cancer is present in 45% of patients with bilateral DVT and is associated with a poor prognosis.

Factors V leiden and II 20210A in patients with symptomatic pulmonary embolism and deep vein thrombosis.

PURPOSE: Factor V Leiden and factor II 20210A are inherited disorders of the clotting system that occur frequently in patients with deep vein thrombosis. We conducted this study to determine whether these factors are also common in patients with pulmonary embolism. SUBJECTS AND METHODS: We determined the prevalence of factor V Leiden and factor II 20210A in 773 consecutive patients with objectively documented symptomatic deep vein thrombosis or symptomatic pulmonary embolism, or with a combination of these disorders. RESULTS: Isolated symptomatic deep vein thrombosis occurred in 345 patients; isolated symptomatic pulmonary embolism occurred in 236; and both anomalies occurred in 192. Factor V Leiden was present in 21 (9%) of the patients with isolated symptomatic pulmonary embolism, in 30 (16%) with both manifestations, and in 63 (18%) with isolated symptomatic deep vein thrombosis (P = 0.007). Factor V Leiden was more common among patients with deep vein thrombosis (odds ratio [OR] = 2.1; 95% confidence interval [CI]: 1.2 to 3.7; P = 0.006) or both pulmonary embolism and deep vein thrombosis (OR = 1.8; 95% CI: 1.0 to 3.3; P = 0.07) than among patients with isolated pulmonary embolism. Factor V Leiden was less common in massive pulmonary embolism (5% [7 of 127]) than in submassive pulmonary embolism (13% [21 of 155], P = 0.03). We found no significant difference in the prevalence of factor II 20210A among the three groups. CONCLUSION: Factors V Leiden and II 20210A vary in prevalence among patients with pulmonary embolism and deep vein thrombosis, suggesting that the risk of pulmonary embolization may vary among patients who have different causes of venous thromboses.

Partial characterization of an autoantibody recognizing the secondary binding site(s) of thrombin in a patient with recurrent spontaneous arterial thrombosis.

A patient with an 18 year history of recurrent arterial thrombosis and no evidence of atherosclerosis or embolism of cardiac origin presented with a prolonged thrombin clotting time when performed with human thrombin. The bovine thrombin clotting time was only slightly prolonged. During 30 months of follow-up, the thrombin time fluctuated, but remained prolonged. The patient has been treated with an oral anticoagulant for the past 8 years, with no thrombotic recurrence. The inhibitor activity was due to the presence of polyclonal IgGs which bound to thrombin-Sepharose. The influence of IgGs purified from the patient's serum was compared to the influence of normal IgGs in several systems exploring the catalytic activity of thrombin and the binding of the enzyme to macromolecular substrates through secondary binding site(s). We found that the IgGs did not impair the catalytic activity toward small synthetic substrates, but inhibited the binding of thrombin to fibrinogen, thrombomodulin and heparin cofactor II. Such proteins are known to require a secondary binding site of thrombin to interact with the enzyme. The anti-thrombin antibody might have resulted from an abnormal generation of thrombin. This would be the consequence of the process favouring thrombosis. Alternatively, the autoantibody might have favoured thrombosis primarily, by impairing natural antithrombotic mechanisms triggered by thrombin.

Antithrombin III Avranches, a new variant with defective serine-protease inhibition--comparison with antithrombin III Charleville.

A decreased plasma antithrombin activity in presence or in absence of heparin was discovered in a 47-year-old patient presenting with recurrent venous thromboembolism. The immunoreactive material (AT III-IR) was normal. The same biological abnormalities were found in two relatives of the patient, leading to the diagnosis of hereditary qualitative AT III deficiency. The propositus' AT III was coeluted with normal AT III from an heparin-sepharose column. An additional step of ion-exchange chromatography on a Mono Q column using a FPLC system (Pharmacia, St-Quentin en Yvelines, France) allowed the purification of a protein which was homogenous in SDS-10% polyacrylamide electrophoresis gel (PAGE). AT III purified from propositus' plasma, normal plasma and the plasma of the patient known to have an AT III variant with defective protease binding (AT III Charleville) were compared. The specific activities measured as heparin cofactor antithrombin or factor Xa inhibition in absence of heparin were decreased to half the normal value. Kinetic studies confirmed a decreased rate of thrombin inhibition for both abnormal AT III preparations. SDS-PAGE experiments performed in purified system and immunoblots obtained from plasma showed that the two variants have different behaviour: in the case of AT III Charleville thrombin induced an apparent 5 k delta increase in molecular mass, probably due to a conformational change. AT III Avranches did not form stoechiometric complexes with thrombin, but was unmodified by the protease.

Effect of local urokinase on arterial occlusion of lower limbs.

Sixty nine patients were treated with local intra-arterial urokinase (37,500 U/CTA. hr-1) for recent severe ischemia of lower limbs: 27 (40%) ultimately required amputation. The difference of amputation rate between the groups with and without thrombolysis was not significant (33% v. 42%). A biological study in 6 patients showed that local arterial plasminemia occurred in only 1 patient. Local urokinase does not strongly stimulate "endogenous" thrombolysis and enhances "exogenous" thrombolysis only very inconstantly. A better adaptation of urokinase dosage or the use of an agent with higher affinity for fibrin might improve the efficiency of local thrombolytic therapy.

A plasma clot lysis assay based on the release of fibrin degradation products: application to the diagnosis of hypofibrinolytic states.

Using a monoclonal antibody-based assay, we measured the fibrin degradation product release in the supernatant of plasma clots obtained before and after venous occlusion (VO) in 30 patients with definite or suspected vascular thrombosis (19 definite and 2 suspected deep vein thrombosis, 6 recurrent superficial thrombophlebitis, 3 arterial occlusions of lower limbs). tPA and PAI-1 concentrations were determined using ELISA assays; the post-occlusion values were corrected for haemoconcentration. The increase in tPA during VO was correlated with haemoconcentration (r = 0.74), but 3 patients had ineffective VO (less than 2% increase in proteins). The fibrinolytic response to VO was evaluated using the shortening of the time necessary for the release of 200 micrograms of fibrin degradation products per mg of fibrinogen (delta T 200). Two among the 27 patients with effective VO were bad responders with a delta T 200 less than 3 h (whereas all the others had delta T 200 greater than 10 h). These patients had respectively a deficient tPA release (delta tPA = 1 ng/ml) and an elevated PAI-1 level at rest (33 ng/ml). Several other patients were bad responders in terms of tPA release or of shortening of the euglobulin clot lysis time but they had a normal delta T 200. This plasma clot test reflects the ability of free tPA to bind to fibrin (the amount of which depends on the level of tPA and PAI-1), and may be useful in the diagnosis of a hypofibrinolytic state.

Comparison of a once daily with a twice daily subcutaneous low molecular weight heparin regimen in the treatment of deep vein thrombosis. FRAXODI group.

BACKGROUND: Clinical trials have been performed to compare with standard heparin a once or a twice daily regimen of low-molecular-weight heparin but no direct comparison has been done between these two low-molecular-weight heparin regimens in terms of efficacy and safety with a long-term clinical evaluation. METHODS: Patients with proximal deep vein thrombosis, confirmed by venography were randomly assigned to either nadroparin (10,250 AXa IU/ml) twice daily or nadroparin (20,500 AXa IU/ml) once daily for at least 5 days. Regimens were adjusted to bodyweight. Oral anticoagulants were started on day 1 or 2 and continued for 3 months. Patients were followed up for 3 months. The composite outcome of venous thromboembolism and death possibly related to pulmonary embolism was the primary measure of efficacy. Major bleeding was the principal measure of safety. The study was designed to show equivalence between the two regimens. RESULTS: Recurrent thromboembolic events or death possibly related to pulmonary embolism were reported in 13 patients in the once daily group (4.1%) and in 24 patients of the twice daily group (7.2%): (absolute difference 3.1% in favor of the once daily regimen; 95% confidence interval -6.6%, +0.5%). Major bleeding episodes during nadroparin treatment occurred in 4 (1.3%) and 4 patients (1.2%) in the once and twice daily groups, respectively. CONCLUSIONS: A nadroparin regimen of one injection per day is at least as effective and safe as the same total daily dose divided over two injections for the treatment of acute deep vein thrombosis.

Heparin-associated thrombocytopenia treatment with low molecular weight heparin.

Eight patients with heparin associated thrombocytopenia (HAT) were treated by a low molecular weight heparin derivative (LMW). Biological and clinical improvement occurred in all patients. This efficiency confirms the antithrombotic activity of LMW and allows its use in patients with HAT.

Molecular basis of antithrombin type I deficiency: the first large in-frame deletion and two novel mutations in exon 6.

We report three novel mutations accounting for cases of inherited type I antithrombin (AT) deficiency. Using the polymerase chain reaction (PCR) and direct sequencing of the coding sequences of the AT gene, we found one mutation in exon 4 and two in exon 6. A deletion of 105 bp causing an in-frame deletion of 35 amino acids between Tyr 240 and Gly 276 was found in exon 4. In a second kindred, deletion of two adenines in codon 412-413 introduced a frameshift and a stop codon at position 431. The last mutation was an insertion of ACCG in codon 387, generating a frameshift with a stop codon located at the normal position. The finding of a sequence repeat of nine residues located at the 5' and 3' ends of the deleted fragment might explain the 105 bp deletion by slippage and mispairing at the replication fork during DNA synthesis. The second mutation is the fourth described within a region of six amino acids (between Phe 408 and Arg 413), which seems to be a cluster of mutations. In this case, the presence of a double repeat sequence--TTCCT and AACA--flanking this region could be particularly favorable for slipped mispairing. These results confirm that human gene mutations are not random events but are strongly influenced by DNA flanking sequences.

A study of fibrinogen and fibrinolysis in 10 adults with nephrotic syndrome.

In 10 patients with nephrotic syndrome (NS), the coagulation inhibitors, the fibrinolytic system and several functions of the fibrinogen-fibrin molecule were studied. Among the coagulation inhibitors, only antithrombin III (AT III) was found decreased and correlated with serum-albumin levels. Venous occlusion test provoked a normal tissue plasminogen activator (tPA) release in all patients. The plasminogen activator inhibitor (PAI) had an increased activity in 5 out of the 10 patients. Thrombin and reptilase times were found abnormal in most patients. The thrombin time (TT) prolongation correlated with serum albumin levels and was corrected by adding purified albumin. The fibrinogen was purified from each of the 10 patients' plasma. Only 2 of them showed abnormal polymerization in purified system, suggesting dysfibrinogenaemia. Other functions (thrombin binding, tPA stimulating activity, lysis by purified plasmin) were found normal except in one of the 2 patients with dysfibrinogenaemia whose fibrinogen lysis by plasmin was delayed. It is concluded that an abnormal fibrinogen molecule is not the most frequent explanation for thrombin time prolongation in NS.

Demonstration of an association between Chlamydia pneumoniae infection and venous thromboembolic disease.

Chlamydia pneumoniae infection has been linked to atherosclerosis, but a possible relationship with venous thromboembolism (VTE) has not been sought. We determined circulating anti-C. pneumoniae antibody levels in patients with VTE. We studied 176 case patients with objectively diagnosed VTE and 197 age- and sex-matched healthy controls, in a retrospective study. Acquired risk factors for VTE and frequent predisposing genetic factors (factor V Arg 506 Gln and factor II G 20210 A mutations) were assessed in all the subjects. Anti-C. pneumoniae IgG antibodies were determined by microimmunofluorescence. All positive plasma samples (titer > or =128) were precisely quantified and tested for the presence of specific IgM antibodies. Fifty-four percent of the cases and 15.9% of the controls had specific IgG titers of at least 256 (p <0.0001). The crude odds ratio for VTE was 6.2 (95% CI, 3.8-10.1), and rose to 7.7 (4.5-13.2) after excluding subjects carrying the factor V Arg 506 Gln or factor II G 20210 A mutations. The odds ratio for VTE increased with the IgG titer: the adjusted odds ratios were 2.1 (95% CI, 1.1-4.1), 5.3 (2.7-10.6) and 33.0 (4.4-248.4) for titers of 256, 512 and 1024, respectively. Only one subject (a case patient) with a high IgG titer (> or =256) also had specific IgM. High titers of anti-C. pneumoniae IgG antibodies are frequently found in patients with previous venous thromboembolism. This association deserves to be confirmed in other case-control studies and prospective studies.

Double-blind, randomized comparison of systemic continuous infusion of 0.25 versus 0.50 mg/kg/24 h of alteplase over 3 to 7 days for treatment of deep venous thrombosis in heparinized patients: results of the European Thrombolysis with rt-PA in Venous Thrombosis (ETTT) trial.

Thirty-two patients with acute, proximal-vein thrombosis were treated with heparin and alteplase (0.25 versus 0.5 mg/kg/24 h during 3-7 days) in a randomized, double-blind, multicenter, European (ETTT) trial. The treatment resulted in a decrease of the venographic Marder's score from 18 (6-25) to 13 (2-24) units (median, range) in Group I (0.25 mg/kg/24 h, n = 15, median decrease 3.0, p = 0.32) and from 17.5 (3-33) to 15.5 (0-27) in Group II (0.5 mg/kg/24 h, n = 16, median decrease 4.0, p = 0.23). Comparison of the sequential venograms could be performed in 14 cases of Group I and in 15 cases in Group II. A minority of patients showed substantial partial recanalization of the initially obstructed veins on the control venogram (one in each treatment group) and most of the control venograms showed either thrombus size reductions (5 in Group I, 7 in Group II) or no change or even deterioration (8 in Group I, 7 in Group II). Major bleedings were observed in 7 patients (7/32, 22%), 5 of them occurring in Group II (5/17, 29%). Thus, the results of the ETTT trial show that the used low dosages of alteplase administered intravenously over 3-7 days in heparinized patients cannot be recommended as a treatment for patients with deep venous thrombosis of lower limbs and/or pelvis. Further studies are needed to define a more suitable dosage regimen of alteplase in this indication.