Impaired Fibrinolytic Capacity Predisposes for Recurrence of Venous Thrombosis

The fibrinolytic capacity of 121 patients with a history of venous thrombosis and/or pulmonary embolism was studied by venous occlusion technique, at earliest 3 months after the last thromboembolic episode. After discontinuation of oral anticoagulation treatment the clinical course of the patients was followed and new thromboembolic episodes were noted. During the observation period of 56 ± 18.8 months 45 of 121 patients experienced recurrence of thrombosis. The recurrence-rate was significantly lower in patients with a post-occlusion ELT shorter than 60 min (4.8%/year) than in patients with an ELT longer than 60 min (10.3%/year). It is concluded that the fibrinolytic capacity is a useful parameter for determining the risk of recurrence in patients with venous thrombosis.

The Prevalence of Hereditary Antithrombin-III Deficiency in Patients with a History of Venous Thromboembolism

Antithrombin-III activity was determined in 752 patients with a history of venous thrombosis and/or pulmonary embolism. 54 patients (7.18%) had an antithrombin-III activity below the normal range. Among these were 13 patients (1.73%) with proven hereditary deficiency. 14 patients were judged to have probable hereditary antithrombin-III deficiency, because they had a positive family history, but antithrombin-III deficiency could not be verified in other members of the family. In the 27 remaining patients (most of them with only slight deficiency) hereditary antithrombin-III deficiency was unlikely. The prevalence of hereditary antithrombin-III deficiency was higher in patients with recurrent venous thrombosis.

T-Cell Alterations in Hemophiliacs Treated with Commercial Clotting Factor Concentrates

Various immunological parameters were determined in 46 patients with severe hemophilia A and in 9 patients with severe hemophilia B. All patients were treated over many years with commercial factor VIII or IX concentrates. Patients with severe classic hemophilia had a significantly reduced relative and absolute number of T-helper cells and a significantly increased relative and absolute number of T-suppressor cells. About half of these patients had an inverse T-helper/suppressor cell ratio. Patients with moderate hemophilia A and severe hemophilia B did not show these abnormalities. Hemophiliacs with an inverse ratio had a significantly higher concentration of serum total protein, IgG and IgM. No relationship between the amount of factor VIII concentrate administered, the HLA-type of the patient, the presence or absence of CMV-antibodies, hepatitis markers, thrombocytopenia and abnormal liver function tests to the T-cell abnormalities could be established. Lymphadenopathy was frequently associated with an inverse ratio. Indirect evidence suggests that the alterations of the immune system began in 1979/80.

Studies on the Specific Fibrinolytic Effect of Human Extrinsic (Tissue-Type) Plasminogen Activator in Human Blood and in Various Animal Species in Vitro

Human extrinsic (tissue-type) plasminogen activator (EPA) was highly purified from the culture fluid of a human melanoma cell line, both as a one-chain or as a two-chain molecule. Its specific fibrinolytic effect on human whole blood clots or plasma clots with different degrees of fibrin crosslinking was evaluated in an in vitro system, composed of a 125I-fibrin labeled clot, hanging in circulating human plasma. After infusion of EPA (30 IU per ml over 3 hrs), non-crosslinked clots lysed more extensively (75-100 percent in 5 hrs) than totally-crosslinked clots (50-65 percent), and no difference was found between one-chain or two-chain EPA. The extent of lysis of totally-crosslinked human or animal plasma clots hanging in autologous plasma induced by EPA varied markedly from one species to the other. When 90 IU of EPA were infused over 3 hrs, crosslinked human plasma clots dissolved for over 95 percent within 5 hrs. Under comparable conditions, the degree of lysis was 80 percent in primate plasma (cynomolgus fascicularis), 60 percent in cat and rabbit plasma, 30 percent in dog plasma and only 10 percent in rat plasma. Systemic activation of the fibrinolytic system in the circulating plasmas was minor and dose-dependent in all species, but complete fibrinogen breakdown was not observed in any species following infusion of up to 90 IU EPA per ml plasma.

It is concluded that the human system is more susceptible to EPA induced fibrinolysis than the other animal systems which were investigated, and that even totally-crosslinked clots can be lysed after infusion of EPA.

Turnover of Human Extrinsic (Tissue-Type) Plasminogen Activator in Rabbits

The turnover of highly purified human extrinsic plasminogen activator (EPA) (one- and two-chain form) was studied in rabbits. Following intravenous injection, EPA-activity declined rapidly. The disappearance rate of EPA from the plasma could adequately be described by a single exponential term with a t ½ of approximately 2 min for both the one-chain and two-chain forms of EPA.

The clearance and organ distribution of EPA was studied by using 125I-labeled preparations. Following intravenous injection of 125I-1abeled EPA the radioactivity disappeared rapidly from the plasma also with a t ½ of approximately 2 min down to a level of 15 to 20 percent, followed by a small rise of blood radioactivity. Gel filtration of serial samples revealed that the secondary increase of the radioactivity was due to the reappearance of radioactive breakdown products in the blood. Measurement of the organ distribution of 125I at different time intervals revealed that EPA was rapidly accumulated in the liver, followed by a release of degradation products in the blood.

Experimental hepatectomy markedly prolonged the half-life of EPA in the blood. Blocking the active site histidine of EPA had no effect on the half-life of EPA in blood nor on the gel filtration patterns of 125I in serial plasma samples.

It is concluded that human EPA is rapidly removed from the blood of rabbits by clearance and degradation in the liver. Recognition by the liver does not require a functional active site in the enzyme. Neutralization in plasma by protease inhibitors does not represent a significant pathway of EPA inactivation in vivo.

Neutralization of Human Extrinsic (Tissue-Type) Plasminogen Activator in Human Plasma: No Evidence for a Specific Inhibitor

Human extrinsic plasminogen activator (EPA), highly purified from a melanoma cell culture fluid is inactivated in human plasma with a half-life (t ½) of 90–105 min. Gel filtration on Ultrogel AcA 34 of mixtures of 125I-labeled EPA and human plasma, incubated at 37°C, revealed the progressive formation of two radioactive components, one with an apparent Mr of 150,000 and one eluting at the void volume. The component with an Mr of 150,000 was identified as consisting at least in part of EPA-α2-antiplasmin complex since: 1) it reacted with antibodies against α2-antiplasmin, but not with antibodies against the other known plasma protease inhibitors, and 2) formation of this component was strongly reduced in plasma specifically depleted in α2-antiplasmin or when the active site of EPA was blocked. The component eluting at the void volume was identified as consisting at least in part of EPA-α2-macroglobulin complex since: 1) it only reacted with antibodies against these two proteins and 2) was not formed in plasma depleted in α2-macroglobulin or when the active site of EPA was blocked.

In purified systems α2-antiplasmin inhibited one-chain EPA with a rate constant of 60 M-1s-1 and two-chain EPA with a rate constant of 130 M-1s-1, which corresponds to a t ½ in plasma of 180 min or 90 min, respectively. α2-Macroglobulin inhibited one-chain EPA with a rate constant of 15 M-1s-1 and two-chain EPA with a rate constant of 30 M-1s-1, which corresponds to a t ½ plasma of 4 or 2 hrs.

All these findings taken together indicate that EPA is slowly neutralized in human plasma primarily by α2-antiplasmin and to a lesser extent by α2-macroglobulin. There appears to be no specific inhibitor in human plasma, which would inactivate EPA either rapidly or to a significant extent.

Bone matrix quality and plasma homocysteine levels

It has recently been reported in the clinical literature that blood homocysteine levels correlate well with fracture risk, although a couple of reports exist to the opposite. Bone strength depends on both bone quantity and quality. The purpose of the present study was to investigate possible correlations between plasma homocysteine levels and bone material properties (Bone Mineral Density Distribution; BMDD, and collagen cross-link ratio). In the present study, femoral heads from subjects (N=19, females, age range 70-95 years old) with known homocysteine plasma levels were investigated. The bone material was collected during hemiarthroplasty surgery. We have determined collagen cross-link ratio and bone mineralization density distribution (BMDD) in bone tissue from patients with acute femoral neck fractures, by Fourier Transform Infrared Imaging (FTIRI) and quantitative Backscattered Electron Imaging (qBEI), respectively. The collagen cross-link ratio that was spectroscopically determined was pyridinoline/divalent cross-links (pyr/divalent). The BMDD variables quantified were: CaMean: the weighted mean calcium concentration; CaPeak: the most frequent Ca concentration; CaWidth: the width of the distribution, a measure of the mineralization homogeneity; CaLow: the percentage of bone area that is mineralized below the 5th percentile in the reference range; CaHigh: the percentage of bone area that is mineralized above the 95th percentile in the reference range. There was a significant correlation between plasma homocysteine levels and collagen cross-link ratio in areas of primary mineralized bone (p<0.0001), unlike the case of trabecular bone surfaces undergoing resorption (p>0.05). On the other hand there was no correlation in any of the BMDD parameters and plasma homocysteine levels (p>0.05). The results are consistent with the known effect of homocysteine on collagen post-translational modifications. These changes were independent of bone mineral characteristics. The results of the present study offer a mechanism by which homocysteine affects bone quality, but caution should be exercised since all patients examined had sustained fracture.

Gamma-hydroxybutyric acid in the treatment of alcohol withdrawal syndrome in patients admitted to hospital

Gamma-hydroxybutyric acid is a gamma-aminobutyric acid analogue which can be found in the human brain and is believed to be a neurotransmitter in the central nervous system. In animal experiments as well as in humans gamma-hydroxybutyric acid has been shown to alleviate the symptoms of the alcohol withdrawal syndrome. 299 patients, who were admitted to hospital for reasons primarily unrelated to their alcohol dependence, were treated with gamma-hydroxybutyric acid when symptoms of the alcohol withdrawal syndrome occurred. Gamma-hydroxybutyric acid was usually given at a daily dose of 50 mg/kg in 3 divided doses, the clinical course of the patients was followed for 7 days or until discharge from hospital. Patients were 214 men and 82 women aged 18-87 years. The reasons for admission to hospital were frequently internal diseases, neurological/psychiatric problems, trauma or surgery. At the start of gamma-hydroxybutyric acid treatment, tremor was present in 81% of patients, sweating in 76% and unrest in 92%. Symptoms occurred 1-72 hours after admission. The efficacy of gamma-hydroxybutyric acid to ameliorate or suppress the symptoms of the alcohol withdrawal syndrome was judged to be excellent in 57%, good in 34%, fair in 18%, insufficient in 3% of patients. Drug tolerance was judged to be excellent in 79%, good in 17%, fair in 2% and poor only in 1% of patients. Adverse events were rare and mild. It is concluded that gamma-hydroxybutyric acid is an attractive alternative to tranquilizers in the management of the alcohol withdrawal syndrome in hospital.

Predicting the risk of restenosis after angioplasty in patients with peripheral arterial disease

Restenosis is a serious therapeutic problem after percutaneous transluminal angioplasty (PTA). Strategies for the prevention of late restenosis include the use of antiaggregatory and anticoagulant drugs, aggressive lipid-lowering, intravascular radiation and others. As some of these therapeutic options are not without side effects it is important to identify patients with an increased risk to develop restenosis. Major clinically recognizable risk factors for restenosis are advanced disease stage and female gender. Elevated plasma levels of fibrinogen, Lp(a), CRP, and migration-inducing activity appear to indicate an unfavorable clinical outcome, and so does post-interventional increase of vWF and PAI-1 antigen. For peripheral arterial disease, only one study has addressed the influence of homocysteine levels upon the restenosis rate after PTA. Although homocysteine levels were elevated in >50% of patients at entry, they were not associated with a higher restenosis rate. Currently the available data allow a rough approximation of a patient's individual risk.

Thromboprophylaxis with 60 mg enoxaparin is safe in hip trauma surgery

BACKGROUND

Little information is available concerning dosage and optimal initiation of thromboprophylactic therapy with low-molecular-weight heparin (enoxaparin) in nonelective hip surgery. The aim of our prospective study was to evaluate the incidence of clinically apparent deep vein thrombosis (DVT), pulmonary embolism (PE), and major hemorrhage in patients receiving thromboprophylaxis with enoxaparin undergoing hip surgery after hip fracture.

METHOD

From 946 consecutive patients admitted with hip fractures, 897 were operated on and received enoxaparin according to the following regimen: Preoperative heparinization from time of admission onwards. Administration of 60 mg enoxaparin, in two doses (20 and 40 mg subcutaneously), during the first 5 days postoperatively. Prophylaxis for a minimum of 5 weeks (40 mg daily).

RESULTS

Clinical signs of DVT were present in 37 patients (4.2%), who all underwent venography. In five patients, DVT was confirmed (0.6%). None of these patients suffered from PE. Another four patients (0.4%) developed clinical signs of PE, and suspected diagnosis was confirmed by computed tomographic scan in two (0.2%). No deaths because of PE were observed. Major hemorrhage occurred in 42 patients (4.7%), there was one death from hemorrhage caused by an intracerebral event. No case of heparin-induced thrombocytopenia type II was observed.

CONCLUSION

Thromboprophylaxis with 60 mg enoxaparin daily, in split doses, starting before surgery, is safe and appropriate in patients with hip fractures. Clinically apparent DVT and PE are rarely observed, and bleeding complications are comparable to those occurring with a conventional thromboprophylactic regimen.

Smooth muscle cell migration promoting activity of plasma predicts restenosis in patients with peripheral arterial occlusive disease undergoing angioplasty

BACKGROUND

Efficacy of percutaneous transluminal angioplasty (PTA) is limited by restenosis occurring in a large proportion of patients. Smooth muscle cell (SMC) migration is a major pathomechanism of restenosis. We studied SMC migration inducing activity of plasma from patients with peripheral arterial occlusive disease (PAOD) undergoing PTA.

METHODS AND RESULTS

SMC migration was determined in a two-dimensional assay system after addition of 1/25 plasma dilutions. Mean increase in migration area was 65.5 +/- 33.8% in normal controls and 67.7 +/- 53.2% in patients with PAOD. 6 hours after PTA, plasmatic migration inducing activity was largely unchanged. In 19/30 patients with restenosis (6 months after PTA) migration promoting activity (82.7 +/- 60.0) was significantly higher than in 11/30 patients with patent vessels (41.8 +/- 21.0; p = 0.03). No correlation of clinical risk factors with outcome was observed. A weak correlation was found between plasmatic migration promoting activity and levels of epidermal growth factor and transforming growth factor-beta.

CONCLUSION

The capacity of human plasma to stimulate SMC migration in tissue culture can be used to assess the risk for restenosis after PTA in patients with PAOD.

Hepatic synthesis and clearance of components of the fibrinolytic system in healthy volunteers and in patients with different stages of liver cirrhosis

We determined plasma levels of tissue-type plasminogen activator (t-PA) antigen, urokinase-type plasminogen activator (u-PA) antigen, and activity of the fast acting inhibitor of plasminogen activator (PAI-1) in patients with different stages of liver cirrhosis (Child A, B, and C) and in age and sex-matched healthy controls to investigate the contribution of the liver to the metabolism of these main components of the fibrinolytic system. For control purposes routine clotting parameters were also determined. In patients with the most severe form of liver cirrhosis (Child C) t-PA antigen levels were significantly elevated as compared to patients with Child A or Child B (p less than 0.05) or to controls (p less than 0.01). Furthermore, Child C patients exhibited significantly decreased PAI-1 plasma levels (p less than 0.05) as compared to controls. We were not able to demonstrate, however, any significant correlation between liver function and u-PA plasma levels. Furthermore, t-PA antigen and albumin plasma levels were negatively correlated (r = 0.48; p = 0.0015) and t-PA antigen and bilirubin were positively correlated (r = 0.46; p = 0.0022) thus indicating that the liver is mainly involved in the clearance of t-PA antigen. PAI-1 activity, however, seems to depend partially on synthesis by the liver as demonstrated by a positive correlation between PAI-1 and albumin (r = 0.33; p = 0.037). These physiologic liver functions are both progressively attenuated in severe liver damage and an increase of t-PA plasma levels and a decrease of PAI-1 might contribute to the higher fibrinolytic tendency observed in those patients.

Disseminated intravascular coagulation and decrease in fibrinogen levels induced by vincristine/prednisolone therapy of lymphoid blast crisis of chronic myeloid leukemia

Therapy with vincristine (2 mg i.v. weekly) and prednisolone (100 mg p.o. daily) caused a decrease in fibrinogen levels in nine patients treated for lymphoid blast crisis LBC) of chronic myeloid leukemia (CML). During the first days of treatment disseminated intravascular coagulation (DIC), evidence by a positive ethanol gelation test, markedly increased thrombin-antithrombin III complex and fibrin-split product D-dimer levels, and a rapid fall in fibrinogen levels was observed in two patients. The induction of DIC in these two patients caused profuse bleeding in one and necessitated substitution therapy with fibrinogen and platelet concentrates. The remaining seven patients revealed no signs of DIC; nevertheless, four of them showed a moderate increase in D-dimer levels after initiation of therapy. In these patients a well-known side effect of long-term steroid therapy, namely a decrease of fibrinogen levels, was observed within the first week of treatment. Fibrinogen levels did not fall below 150 mg/dl and increased after dose reduction from 100 mg/day to 50 mg/day. We conclude from our results that two types of disturbances in fibrinogen metabolism can be observed during vincristine/prednisolone therapy of LBC of CML: (a) a decrease of fibrinogen levels due to a steroid-mediated impairment of liver synthesis, and (b) a rapid fall in fibrinogen levels in the course of DIC, most likely induced by the release of procoagulants from deteriorating blast cells, leading to severe bleeding in selected cases.

Activation of coagulation and fibrinolysis in patients with arteriosclerosis: relation to localization of vessel disease and risk factors

Activation markers of blood coagulation and fibrinolysis and several fibrinolytic parameters were determined in arteriosclerotic patients to investigate the relation between extension and main localization of vessel disease, risk factors and disturbances within the blood coagulation and the fibrinolytic system. Indications of an increased intravascular fibrin formation and subsequent fibrinolysis were found in peripheral artery disease (PAD) patients but not in coronary artery disease (CAD) patients. Compared with healthy controls PAD patients had elevated TAT (median: 3.2 ng/ml, 1.5-70 vs. 2.1, 1.2-4.7, p less than 0.005) and D-Dimer (median: 365 ng/ml, range 85-2000 vs. 185, 79-360; p less than 0.0001) plasma levels, whereas TAT (2.4, 1.2-13) and D-Dimer (190, 58-1000) levels of CAD patients were in the normal range. No associations were detected between risk factors of arteriosclerosis (hyperlipidemia, diabetes mellitus, cigarette smoking, hypertension) and the plasma levels of the activation markers TAT and D-Dimer. Independent from risk factors PAD and CAD patients had elevated plasma plasminogen activator inhibitor capacity (PAI cap). Our results provide evidence that 1) increased plasma levels of blood coagulation and fibrinolysis activation markers are not related to risk factors of arteriosclerosis but seem to be unspecifically caused by activation processes on arteriosclerotic vessel wall defects, 2) increased plasma PAI cap found in arteriosclerotic patients is a relatively unspecific phenomenon associated with arterial vessel disease.

[A fatality caused by heparin overdose]

Because of suspected pulmonary embolism 550.000 I.U. of heparin were administered instead of 55.000 I.U. of heparin within 24 h to a 62 year old patient. The man died because of cerebral hemorrhage the following day. Autopsy findings are reported and difficulties in medical expertise are discussed.

Evidence for an increased generation of prostacyclin in the microvasculature and an impairment of the platelet alpha-granule release in chronic renal failure

The formation of prostacyclin (PGI2) and thromboxane A2 and the release of beta-thromboglobulin (beta-TG) at the site of platelet-vessel wall interaction, i.e. in blood emerging from a standardized injury of the microvasculature made to determine bleeding time, was studied in patients with end-stage chronic renal failure undergoing regular haemodialysis and in normal subjects. In the uraemic patients, levels of 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha) were 1.3-fold to 6.3-fold higher than the corresponding values in the control subjects indicating an increased PGI2 formation in chronic uraemia. Formation of thromboxane B2 (TxB2) at the site of plug formation in vivo and during whole blood clotting in vitro was similar in the uraemic subjects and in the normals excluding a major defect in platelet prostaglandin metabolism in chronic renal failure. Significantly smaller amounts of beta-TG were found in blood obtained from the site of vascular injury as well as after in vitro blood clotting in patients with chronic renal failure indicating an impairment of the alpha-granule release in chronic uraemia. We therefore conclude that the haemorrhagic diathesis commonly seen in patients with chronic renal failure is--at least partially--due to an acquired defect of the platelet alpha-granule release and an increased generation of PGI2 in the microvasculature.

[High dosage and intermediate dosage cytosine arabinoside in the treatment of secondary leukemias]

Patients with secondary acute myeloid leukaemia (AML) following treatment with alkylating agents and/or radiation show a poor response to standard induction therapy. Between 1983-1987 8 consecutive patients were treated with high-dose cytosine arabinoside (HD-ARA C; 3 g/sqm twice daily for 6 days) or intermediate-dose cytosine arabinoside (ID-ARA C; 0.5 g/sqm twice daily for 6 days). Complete remission was achieved in 3 patients (HD-ARA C: 2/3l; ID-ARA C: 1/5) and partial remission in 3 patients (ID-ARA C: 3/5). One patient (HD-ARA C) died during prolonged aplasia, one patient (ID-ARA C) proved refractory to treatment. The respective duration of remission in the 3 responsive patients was 3, 7 and 8 months. The probability of survival of the whole group was 50% after 12 months and 25% after 24 months. Our results confirm the efficacy of monotherapy with ARA C in the treatment of secondary AML. Consolidation therapy with ID-ARA C for 4 days seems to prolong remission.

[Home treatment in hemophilia]

88 patients with severe haemophilia (66 with haemophilia A without inhibitor, 12 with haemophilia A and inhibitor, 10 with haemophilia B) currently receive comprehensive care at the Vienna haemophilia centre. Data available at the centre and a questionnaire answered by the hemophiliacs were used in order to evaluate the current situation of home care. At present, 62 (70%) out of 88 patients receive home treatment (51 with haemophilia A without inhibitor, 5 patients with haemophilia A and inhibitor and 6 with haemophilia B). For treatment of joint and muscle bleeding mean dosages of 15.3 units/kg body weight of factor VIII concentrate, 17.0 units/kg of factor IX concentrate and 30 units/kg of FEIBA were administered by the hemophiliacs. Children and young patients required higher doses (30 and 17.4 units/kg F VIII, respectively). Two thirds of the bleeding episodes were successfully treated by a single infusion. No severe side effects were observed during home treatment. Home treatment has been widely accepted by the patients. It is regarded as a practical and safe therapy and has improved the life quality of haemophiliac patients.

Enhanced fibrinolysis caused by tissue plasminogen activator release in hemodialysis

The effect of hemodialysis on components of the fibrinolytic system was measured in 22 patients. Plasma levels of t-PA antigen, t-PA activity, u-PA antigen and plasminogen activator inhibitor were determined by means of immunological and functional assays. During hemodialysis, 11 patients exhibited an increase in t-PA antigen within the first hour to about three times the starting values (P less than 0.05), followed by a decrease to about double of the initial values until the end of the treatment. Eleven patients showed a continuous increase up to 200% of the starting values until the end of hemodialysis. u-PA levels did not change significantly during the time of investigation (P greater than 0.5).

Evaluation of fibrinolytic capacity by a combined assay system for tissue-type plasminogen activator antigen and function using monoclonal anti-tissue-type plasminogen activator antibodies

An assay system has been developed that allows consecutive quantification of tissue-type plasminogen activator (t-PA) activity and t-PA antigen in the same plasma sample. In the first step t-PA is bound to an immobilized IgM monoclonal anti-t-PA antibody and functional activity of bound t-PA is quantified by its plasminogen-activating activity. In the second step the amount of bound t-PA antigen is determined by using a different peroxidase-labeled monoclonal anti-t-PA antibody. In this combined assay system t-PA functional activity was found to depend not only on the amount of t-PA antigen but also on the amount of plasminogen activator inhibitor (PAI), whereas in the t-PA antigen assay PAI did not affect the results. In plasma samples obtained from normal controls t-PA activity was detected only in post-venous occlusion plasma (3.7 +/- 2.5 IU/ml), whereas 2.7 +/- 0.5 ng/ml t-PA antigen was found before and 12.6 +/- 4.4 ng/ml after venous occlusion. Using this combined assay system to study plasma samples from patients who did not respond to venous occlusion with shortening of the euglobulin clot lysis time (ECLT), it was possible not only to confirm that in none of these patients could t-PA activity be detected in the postocclusion plasma samples but also to subdivide that group of patients into a group of about 39% not reacting with normal t-PA antigen release to venous occlusion and into a second group of about 61% that reacted with normal t-PA antigen release.(ABSTRACT TRUNCATED AT 250 WORDS)

[Oral anticoagulant therapy--renaissance of an old therapy?]

Although the antithrombotic potential of oral anticoagulants is undisputed, bleeding complications constitute a serious problem. One of the main causes for these complications has been a lack of standardization of the prothrombin time. The introduction of the International Normalized Ratio (INR) has led to a better standardization of prothrombin time. Thus, the same level of anticoagulation can be reached using different reagents and therefore over- and undercoagulation can be avoided. Furthermore, the benefit/risk ratio can be improved by adapting the intensity of anticoagulation to the indication. The following clinical conditions are established indications for treatment with oral anticoagulants: Prevention of cardiac emboli in acute anterior myocardial infarction with atrial thrombus, in patients with atrial fibrillation with or without mitral valve disease, in patients with prosthetic heart valves and in patients with dilated cardiomyopathy. Furthermore, oral anticoagulants should be given to patients after femoropopliteal bypass. A relatively mild oral anticoagulant treatment (INR 2-3) is sufficient to prevent recurrences of venous thrombosis and pulmonary emboli. The duration of treatment in patients with venous thromboembolism depends on some clinical features and the results of clotting tests which indicate an increased tendency to thrombosis.

[Right heart failure as a clinical sign of pulmonary artery sarcoma]

A 43 year-old female patient was admitted on account of severe dyspnoea of several months' duration and thrombocytopenia. The clinical symptomatology was compatible with pulmonary embolism, but no source of embolization was found and heparin therapy did not lead to clinical improvement. Angiography of the pulmonary artery revealed multiple filling defects. Symptoms improved after treatment with cortisone and so a malignant process was assumed. The patient died from right ventricular failure before the diagnosis could be established. At autopsy a sarcoma of the pulmonary artery, obviously originating from the pulmonary trunk was found. Thrombocytopenia most probably resulted from consumption of platelets by a mechanism corresponding to the Kasabach-Merritt syndrome. The difficulties in the diagnosis of pulmonary artery sarcomas are discussed and the 69 previously published cases are reviewed.

Incidence of inhibitors in patients with severe and moderate hemophilia A treated with factor VIII concentrates

Recent data published on the prevalence of inhibitors to factor VIII in hemophiliacs on treatment show great variations, with prevalence rates ranging from 3.6 to 14.2%. We have studied the cumulative risk of inhibitor development in a cohort of 62 patients with hemophilia A. All patients were born after 1960, were natives of the Vienna area, had a factor VIII activity of less than 5%, and were treated at least once. Using the method of Cutler and Ederer, the cumulative risk of inhibitor development was found to be 24% at the age of 25 years. Most inhibitors developed between the ages of 3 and 7 years. The current prevalence of F VIII inhibitors in the group of patients studied is 17.5%. It is concluded that prevalence data underestimate the true risk of inhibitor development.

Sandwich ELISA for t-PA antigen employing a monoclonal antibody

A sandwich enzyme-linked immunosorbent assay (ELISA) for determination of tissue-type plasminogen activator (t-PA) was developed. 96-well flat-bottom polystyrene plates were coated with polyclonal (goat) anti t-PA IgG (10 micrograms/ml). After addition of samples monoclonal (murine) anti t-PA IgG (1.5 micrograms/ml) was added. Finally, peroxidase labelled anti-mouse IgG (goat) was used to quantify the bound second antibody. The assay can be used for determination of t-PA antigen in purified systems, in cell culture supernatants, and in human plasma, provided that EDTA (0.005 M) is present in the sample. In 78 healthy volunteers, t-PA antigen levels at rest were 0.4 - 15.2 ng/ml (4.3 +/- 2.7, means +/- S.D.); A significant positive correlation between t-PA antigen and age could be demonstrated.

Increased risk of thrombosis due to abnormalities of the hemostatic system

In recent years a number or hereditary or acquired abnormalities of the hemostatic system have been discovered which predispose to thrombosis. The type of this abnormality determines not only whether there is a tendency to venous or arterial thrombosis but also predisposes in some instances to thrombosis at a specific site. Such hemostatic abnormalities may be present in 10-30% of patients with a history of venous thrombosis. The detection of a thrombophilic state has important implications as regards the choice and the duration of antithrombotic treatment.

The prevalence of hereditary antithrombin-III deficiency in patients with a history of venous thromboembolism

Antithrombin-III activity was determined in 752 patients with a history of venous thrombosis and/or pulmonary embolism. 54 patients (7.18%) had an antithrombin-III activity below the normal range. Among these were 13 patients (1.73%) with proven hereditary deficiency. 14 patients were judged to have probable hereditary antithrombin-III deficiency, because they had a positive family history, but antithrombin-III deficiency could not be verified in other members of the family. In the 27 remaining patients (most of them with only slight deficiency) hereditary antithrombin-III deficiency was unlikely. The prevalence of hereditary antithrombin-III deficiency was higher in patients with recurrent venous thrombosis.

[Plasminogen activator of tissue type. Physiology, pathophysiology and clinical value]

Tissue-type plasminogen activator (t-PA), the major physiological activator of fibrinolysis, is contained in most human organs, tissues and secretions. t-PA is synthesized by endothelial cells and is released, in response to various stimuli, into the blood stream. Activation of plasminogen by t-PA is greatly enhanced in the presence of fibrin, whereby the fibrinolytic process is confined to the immediate environment of a formed thrombus. The enzymatic activity of t-PA is controlled by a fast-acting plasminogen activator inhibitor. Methods are now available for the immunological and functional determination of t-PA in biological fluids. The major function of plasmatic t-PA is the lysis of intravascular fibrin deposits. A reduced capacity to liberate functionally active t-PA from the vessel wall may result in the development of a thrombotic tendency. Extravascular t-PA is involved in various processes associated with cell migration and tissue remodelling. Purified t-PA preparations have been shown to induce marked fibrinolysis and thrombolysis with negligible fibrinogenolysis, in vitro and in various animal models. At present, the efficacy of recombinant t-PA in the lysis of arterial and venous thrombi is being tested in man.

Prevention of arterial and pulmonary embolism by oral anticoagulants in patients with dilated cardiomyopathy

The incidence of arterial embolism (AE) and pulmonary embolism (PE) during treatment with oral anticoagulants (OA) or without OA therapy was studied in 38 patients with dilated cardiomyopathy (DCMP). AE/PE occurred in 17 patients (44.7%) before initiation of OA treatment. The severity of DCMP was a risk factor for AE/PE, but not the presence of atrial fibrillation or intracardial thrombi. No AE/PE episodes occurred during the period of OA therapy. No major bleeding complications were seen, probably due to the moderate intensity of OA therapy (therapeutic range 5-15% Thrombotest [TT], 2.1-4.8 International Normalized Ratio [INR], median TT value 11%, median INR 2.6). Recurrence of AE was observed in 4 of 5 patients in whom treatment with OA had been discontinued.

Tissue plasminogen activator inhibitor in human plasma: development of a functional assay system and demonstration of a correlating Mr = 50,000 antiactivator

An assay system for determination of the "fast"-acting inhibitor (antiactivator, AA) of tissue-type plasminogen activator (tPA) in human plasma was developed. The system is based on incubation of plasma samples with various amounts of vessel wall-derived tPA for 8 minutes at 25 degrees C, followed by acidification and determination of the residual tPA activity by an indirect spectrophotometric assay. One unit of AA was defined as the amount inhibiting 1 U of tPA. AA levels in normal controls (n = 26) were 1.4 to 17.4 U/ml (median 3.0 U/ml) and 0.9 to 17.5 U/ml (median 3.0 U/ml) in patients with a history of deep venous thrombosis (n = 26). When plasma was subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis followed by reverse fibrin autography, AA activity appeared as an inhibitory band corresponding to a relative molecular mass of 50,000. In six samples the inhibitory activity of this band was directly correlated to the functional AA activity of the plasma samples.

Deficiency of fibrinogen and factor VII following treatment of severe aplastic anaemia with anti-thymocyte globulin and high-dose methylprednisolone

In 4 patients with SAA treated with ATG and high-dose MP, an as yet unrecognized acquired deficiency of fibrinogen and factor VII was observed. The plasma level of fibrinogen fell to 39% (34-51%) and of factor VII:C to 50% (31-55%) of the pretreatment value. The nadirs were between days 10 and 35 (fibrinogen) and d 3 and 11 (factor VII) after the 1st dose of ATG/MP. From additional clotting studies it is concluded that disseminated intravascular coagulation, fibrinolysis, liver cell damage and synthesis of abnormal clotting factors are unlikely causes of these clotting abnormalities. The most probable explanation seems to be a selective inhibition of the synthesis of fibrinogen and factor VII by an as yet unknown mechanism. These clotting abnormalities might, to some extent, increase the bleeding tendency in these patients, which up to now had been solely attributed to thrombocytopenia.

[Use of monoclonal antibodies in the diagnosis of fibrinolysis]

Monoclonal antibodies to tissue type plasminogen activator (t-PA), urokinase (u-PA) and alpha-2-antiplasmin were obtained by immunizing Balb C mice with the respective purified antigens and fusion of spleen cells with mouse myeloma cells (NSO). The selected monoclonal antibodies reacted exclusively with the respective antigens used for immunization. 3 out of 7 monoclonal antibodies directed against t-PA inhibited plasminogen activation by t-PA and 6 of 7 interfered with the fibrin potentiating effect. Only one out of 5 monoclonal antibodies directed against u-PA inhibited plasminogen activation by u-PA. None of the monoclonal antibodies directed against t-PA or u-PA inhibited the cleavage of low molecular weight paranitroanilide substrates by the respective plasminogen activators. Likewise, the 3 monoclonal antibodies to alpha-2-antiplasmin did not functionally inhibit alpha-2-antiplasmin. The selected monoclonal antibodies were used to develop sensitive test systems for the respective antigens. The lower detection limit for determination of t-PA was found to be 0.5 ng/ml, for determination of u-PA 0.05 ng/ml, and for determination of alpha-2-antiplasmin 5 ng/ml.

Treatment of severe chronic idiopathic thrombocytopenic purpura in adults with high-dose intravenous gammaglobulin

12 patients with severe chronic idiopathic thrombocytopenic purpura (ITP) were treated with i.v. polyvalent intact immunoglobulin (0.14-0.4 g/kg body weight for 5 d) because of various bleeding episodes or prior to surgery. In 9 patients a significant rise in platelet counts was noted, starting on d 2 and reaching its maximum between d 4 and 11. Thereafter, platelet counts decreased slowly, approaching pre-treatment values after 20 d in most cases. Response to immunoglobulin was reproducible, when infusions were repeated. Response to high-dose immunoglobulin was independent of age of patients and duration of disease. Platelet-associated IgG decreased in all patients tested. A pepsin-treated immunoglobulin preparation was ineffective in 3 patients.

CRM+ severe Fletcher factor deficiency associated with Graves' disease

A 59-year-old male patient with Graves' disease and severe hereditary Fletcher factor deficiency is described. PKK clotting activity as well as the activity by a chromogenic substrate method (Chromozym PK) was less then 0.01 U/ml. In contrast to functional tests, the immunological assay (Laurell method) showed a PKK antigen concentration of 0.25 U/ml, indicating the presence of an abnormal nonfunctional PKK molecule (CRM+ variant). An inhibitor was excluded since the patient plasma did not inactivate partially purified PKK. Investigation of 11 family members revealed a reduction of the PKK clotting activity in 9 relatives of the patient. Since Graves' disease is considered an autoimmune disease, our case represents an example of an association of a severe hereditary deficiency of a contact factor and an autoimmune disease.

Prevention of Arterial and Pulmonary Embolism by Oral Anticoagulants in Patients with Dilated Cardiomyopathy

The incidence of arterial embolism (AE) and pulmonary embolism (PE) during treatment with oral anticoagulants (OA) or without OA therapy was studied in 38 patients with dilated cardiomyopathy (DCMP). AE/PE occurred in 17 patients (44.7%) before initiation of OA treatment. The severity of DCMP was a risk factor for AE/PE, but not the presence of atrial fibrillation or intracardial thrombi. No AE/PE episodes occurred during the period of OA therapy. No major bleeding complications were seen, probably due to the moderate intensity of OA therapy (therapeutic range 5-15% Thrombotest® [TT], 2.1-4.8 International Normalized Ratio [INR], median TT value 11%, median INR 2.6). Recurrence of AE was observed in 4 of 5 patients in whom treatment with OA had been discontinued.

Impaired fibrinolytic capacity predisposes for recurrence of venous thrombosis

The fibrinolytic capacity of 121 patients with a history of venous thrombosis and/or pulmonary embolism was studied by venous occlusion technique, at earliest 3 months after the last thromboembolic episode. After discontinuation of oral anticoagulation treatment the clinical course of the patients was followed and new thromboembolic episodes were noted. During the observation period of 56 +/- 18.8 months 45 of 121 patients experienced recurrence of thrombosis. The recurrence-rate was significantly lower in patients with a post-occlusion ELT shorter than 60 min (4.8%/year) than in patients with an ELT longer than 60 min (10.3%/year). It is concluded that the fibrinolytic capacity is a useful parameter for determining the risk of recurrence in patients with venous thrombosis.

Protein C deficiency in two Austrian families

Protein C antigen was determined by Laurell rocket immunoelectrophoresis in 225 patients with a history of venous thrombosis. Among these patients two females with protein C deficiency were detected. Additional studies in the families of the protein C deficient patients revealed further 7 family members with protein C deficiency. In 8 not anticoagulated patients with protein C deficiency the protein C ranged from 36 to 62% (median: 45%). In one patient on oral anticoagulant treatment protein C antigen concentration was less than 10%, F II and FX were 65 and 50%, respectively. The pattern of inheritance was consistent with autosomal dominant inheritance. 5 of the 9 protein C deficient patients had severe thrombotic tendency characterized by recurrent deep venous thrombosis (n = 4), pulmonary embolism (n = 1), probable mesenteric vein thrombosis (n = 1) and superficial thrombophlebitis (n = 2). All protein C deficient patients without thrombosis were less than 17 years old.

1-Deamino-8-D-arginine-vasopressin--an alternative in the management of mild haemophilia A and von Willebrand's disease

Intravenous administration of 0.4 micrograms DDAVP/kg body weight in 16 normal controls, 34 patients with haemophilia A and 30 patients with von Willebrand's disease (vWd) was followed by an increase in FVIII: C from 230 to 410%, in FVIIIR:Ag from 160 to 260% and FVIIIR:RC of from 160 to 320%. Additionally, in the patients with vWd, a shortening of the bleeding time and improvement in platelet retention was observed. In 7 haemophiliacs with pretreatment levels of FVIII: C ranging from between 11 and 43% dental extractions were performed successfully after DDAVP whereas in 2 patients with FVIII: C levels of 5 and 6%, respectively, severe bleeding necessitated administration of factor VIII concentrates. In 8 haemophiliacs (FVIII: C between 6.5 and 50%) and 2 patients with vWd (FVIII: C 18 and 36%, respectively) DDAVP enabled minor surgery and successful therapy of spontaneous or traumatic bleeding complications. However, severe postoperative bleeding after stomach surgery in 2 haemophiliacs (FVIII: C 23 and 40%, respectively) and severe menstrual bleeding in one patient with vWd (FVIII: C 15%) required administration of factor VIII concentrates. At present DDAVP therapy should be restricted to minor surgery and non-life-threatening, spontaneous or traumatic bleeding complications in patients with pretreatment FVIII: C levels higher than 10%.

T-cell alterations in hemophiliacs treated with commercial clotting factor concentrates

Various immunological parameters were determined in 46 patients with severe hemophilia A and in 9 patients with severe hemophilia B. All patients were treated over many years with commercial factor VIII or IX concentrates. Patients with severe classic hemophilia had a significantly reduced relative and absolute number of T-helper cells and a significantly increased relative and absolute number of T-suppressor cells. About half of these patients had an inverse T-helper/suppressor cell ratio. Patients with moderate hemophilia A and severe hemophilia B did not show these abnormalities. Hemophiliacs with an inverse ratio had a significantly higher concentration of serum total protein, IgG and IgM. No relationship between the amount of factor VIII concentrate administered, the HLA-type of the patient, the presence or absence of CMV-antibodies, hepatitis markers, thrombocytopenia and abnormal liver function tests to the T-cell abnormalities could be established. Lymphadenopathy was frequently associated with an inverse ratio. Indirect evidence suggests that the alterations of the immune system began in 1979/80.

[Bone marrow transplantation for aplastic anemia--initial results in 8 patients]

8 young patients (aged 11 to 23 years) with severe aplastic anaemia received bone marrow grafts from their HLA-identical, MLC-non reactive siblings. All patients had received repeated transfusions previously and had been unsuccessfully treated with corticosteroids (7 out of the 8 patients) and/or anabolic drugs (4 out of the 8 patients). In order to prevent graft rejection 5 patients received donor buffy coat cells after the marrow infusion and 3 patients underwent total body irradiation with 400 rad prior to the marrow transplantation. 5 patients are alive, 3 patients died. Death occurred from Candida septicaemia (day 4 after transplantation), left ventricular failure (day 14) and graft versus host reaction of the gut (day 85). The 5 living patients are in a very good state of health 30 to 166 days after transplantation. 4 patients already have normal blood cell counts. 2 of the surviving patients developed a transient GVH-reaction of the liver. One patient had a mild GVH-reaction of the skin on day 130.

The effect of histamine2 and muscarine receptor antagonists on plasma levels of parathyroid hormone and calcitonin

Long-term administration of cimetidine, a histamine2 receptor antagonist, has been reported to normalize elevated parathyroid hormone (PTH) concentrations in patients with secondary [1] and primary hyperparathyroidism [2] and even to improve the clinical symptoms. We have compared the effect of cimetidine and pirenzepine on PTH and calcitonin (CT) plasma levels in a short-term trial on patients with secondary hyperparathyroidism. After cimetidine a significant effect on PTH was seen within 30 min lasting 30 min and after pirenzepine, within 60 min and lasting 60 min. The effect on CT was only significant after cimetidine.

[New aspects of chlorprothixen-poisoning (author's transl)]

Over the past 8 years the Poison Information Centre of Vienna was confronted 24 times with acute chlorproxithene (CPTX) poisoning. In adults doses of 2 g and more caused severe intoxication, but serious toxic manifestations were observed already at low dosage in children (after the ingestion of less than 5 mg/kg body weight). In one case unexpected death due to cardiac failure occurred as long as 49 hours after CPTX intake. The favorable outcome in one patient treated with gut, as well as gastric lavage indicates that this therapeutic strategy may be of value in the management of CPTX intoxication.

Thrombolysis with human extrinsic (tissue-type) plasminogen activator in dogs with femoral vein thrombosis

Extrinsic (tissue-type) plasminogen activator (plasminogen activator) was isolated either as a single-chain or as a two-chain molecule from the culture medium of a human melanoma cell line. The thrombolytic activity of both molecular forms of activator was investigated in beagle dogs with an experimental femoral vein thrombosis and compared with that of urokinase. The 125I-fibrinogen-labeled thrombus was formed in an isolated 4-cm segment of the vein, aged for 30 min, and the thrombolytic substances were infused over a 4-h period. The degree of thrombolysis was measured 2 h later as the difference between the injected and recovered 125I. In six control animals with a saline infusion the extent of thrombolysis was 16.3 +/- 3.8% (mean +/- SEM), in five dogs receiving 100,000 IU urokinase, 17.4 +/- 3.7% (P less than 0.4) and in four dogs with 1,000,000 IU urokinase 40.6 +/- 4.8% (P less than 0.001). Infusion of 100.000 IU single-chain plasminogen activator in five dogs resulted in 3.5 +/- 7.8% lysis (P less than 0.05) and of 100,000 IU two-chain plasminogen activator in five dogs in 60.1 +/- 10.8% (P less than 0.001). Infusion of 300,000 IU one-chain plasminogen activator yielded 57.5% lysis and of the same amount of two-chain plasminogen activator 72.9%. Significant activation of plasminogen, consumption of alpha 2-antiplasmin, and fibrinogen breakdown in plasma was only observed in animals receiving the high doses of urokinase but not in the saline, plasminogen activator, or the low-dose urokinase groups. It is thus concluded that in this thrombosis model human extrinsic plasminogen activator has a higher specific thrombolytic effect that urokinase. Plasminogen activator also appears to induce thrombolysis without systemic fibrinolytic activation and fibrinogen breakdown.