The PLAT Study: a multidisciplinary study of hemostatic function and conventional risk factors in vascular disease patients.

In this paper are reported the basal results of a multidisciplinary, multicenter study designed to explore in a population with ischemic disease the relation between hemostatic variables, conventional risk factors and atherothrombotic sequelae. 953 patients less than or equal to 69 yrs with documented coronary, cerebral or peripheral atherosclerotic disease were studied and followed-up for 24 months. Examinations included hemostatic and lipid laboratory assays, arterial Doppler examination, cerebral computerized tomography and nuclear magnetic resonance, exercise electrocardiogram and coronary angiography. Fibrinogen (301.4 +/- 71.52 mg/dl) correlated positively with antithrombin III (r = 0.27) and leukocytes (r = 0.25), negatively with HDL-cholesterol (r = 0.18) and tended to increase with smoking. Heavy smokers had higher leukocyte counts than non-smokers (8.0 +/- 2.0 vs. 7.2 +/- 2.1 x 10(3)/microliters), higher triglycerides (1.87 +/- 1.12 vs. 1.53 +/- 1.35 mmol/l) and lower HDL-cholesterol (0.93 +/- 0.27 vs. 1.00 +/- 0.25 mmol/l). FVII correlated positively with triglycerides (r = 0.16) and protein C (r = 0.45). vWF:Ag (145.4 +/- 70.58%) ad FVII:C (139.7 +/- 59.10%) were positively correlated (r = 0.44). FVIII:C correlated positively with fibrinogen (r = 0.21). Myocardial infarction survivors with associated cerebral and peripheral vascular lesions had higher FVIII:C, FVII, fibronogen and vWF:Ag. These findings suggest that hemostatic factors may enhance and/or mediate the effects of conventional risk factors in atherothrombotic ischemic events.

Idarubicin in the therapy of acute myeloid leukemia: final analysis in 57 previously untreated patients.

Fifty-seven previously untreated adult acute myeloid leukemia patients received idarubicin (IDA) in sequential combination with cytarabine as induction therapy; post-remission treatment included two courses of IDA and cytarabine alternating with two courses of VP-16 and cytarabine. As late intensification, patients received either high-dose cytarabine or, in 10 cases, autologous bone marrow transplantation. Complete remission (CR) was achieved in 48 patients (84.2%), 41 after one induction course and seven after two courses. Median length of disease-free survival (DFS) was 26 months. Univariate analysis did not identify any of the investigated variables as having prognostic significance in predicting DFS. On the other hand, patients achieving CR after one induction course had a better DFS than those requiring two courses. Furthermore, the analysis of DFS slightly favors autologous bone marrow transplantation. In conclusion, the antileukemic activity of the present IDA protocol is testified by the high CR rate and by the possibility of minimizing the role of prognostic factors. The better outcome of patients achieving CR after one induction course further supports the opinion that the intensity of the induction treatment, offered by an agent as potent as IDA, might significantly influence DFS.

GAGs-potentiated inhibition of thrombin, factor Xa and plasmin in plasma and in a purified system containing antithrombin III - correlation with total charge density.

The ability of heparin and related glycosaminoglycans (GAGs) to accelerate the inhibition of thrombin, factor Xa and plasmin in plasma and in a purified system containing antithrombin III (At III) was studied using chromogenic peptide substrate assays. There was good correlation between the charge density of the mucopolysaccharides and the activities investigated. While the difference between potentiation of the antithrombin activity by GAGs in plasma and in the purified system was slight, the inhibition of factor Xa in plasma was more pronounced than in the presence of purified At III, indicating the mechanisms for GAGs-potentiated inhibition of thrombin and factor Xa are not identical. For the antiplasmin activity, there was a good correlation between the chemical structure and biological activity only in the pure system, confirming that the antithrombin-GAG complex plays a very limited role in the inactivation of plasmin in plasma.

Coagulation activation markers in the prediction of venous thrombosis after elective hip surgery.

BACKGROUND: Despite prophylaxis, deep vein thrombosis (DVT) after hip surgery continues to occur frequently. Thus it would be helpful if before surgery patients at higher risk of DVT could be identified and more adequate prophylaxis given. As part of an international study on the prevention of DVT after total hip replacement, we investigated whether preoperative levels of three coagulation activation markers, prothrombin fragment F1 + 2 (F1 + 2), thrombin-antithrombin III complexes (TAT) and D-dimer, correlate with results of postoperative venography. METHODS: 159 patients undergoing total hip replacement were randomized to receive 10, 15 or 20 mg desirudin bid or 5000 IU unfractionated heparin tid immediately before surgery and then for 11 days, until bilateral venography was performed. Preoperative F1 + 2, TAT and D-dimer plasma levels were measured using ELISA procedures. As no difference among anticoagulant treatments or in the interaction between treatments and DVT was detected for any of the three variables, results are reported as pooled data. FINDINGS: The frequency of DVT was 18.8% in the low (0.75-1.33 nM) vs 65.7% in the high third of distribution (1.77-3.47 nM) of F1 + 2 (p < .001), 27.3% in the low (2.00-2.50 micrograms/l) vs 57% in the high third (5.10-61.00 micrograms/l) of TAT (p = .042), and 29.4% in the low (39-59 micrograms/l) vs 57.1% in the high third (129-651 micrograms/l) of D-dimer (p = .051). INTERPRETATION: Preoperative F1 + 2, TAT and D-dimer levels are associated with the risk of development of DVT after total hip replacement.

Selective PF4 release in vitro induced by heparin and related glycosaminoglycans (GAGs)--correlation with beta-TG release and platelet aggregation.

We studied human platelet aggregation and beta-TG/PF4 release induced by heparin and related GAGs in vitro both in normal PRP and in PRP after aspirin. In our experimental conditions, heparin and related GAGs always caused PF4 release in vitro from normal platelets, whether or not there was measurable platelet aggregation in the aggregometer. Significant beta-TG release was induced only by the mucosal heparin preparation (which also induced platelet aggregation in some citrated PRP). Therefore, while beta-TG release in vitro seems to correlate with platelet aggregating activity of heparin, the selective PF4 release, caused by heparin and related GAGs also in conditions in which neither platelet aggregation nor beta-TG are measurable, is probably associated with the high affinity of PF4 for heparin. The degree of affinity of GAGs for PF4 (heparin greater than DeS greater than HS) seems to correlate with PF4 release. Moreover, the significant reduction in PF4 release in vitro after aspirin suggests that GAGs-induced PF4 release is related to a cyclooxygenase-dependent activation process.

Daunorubicin and platelet function.

The influence of Daunorubicin on some platelet functions in vitro was investigated, using different concentrations of the drug (0.01-0.02-0.04 microgram/ml). Daunorubicin was shown to inhibit Collagen and Thrombin induced platelet aggregation and the intensity of inhibition on both drug concentration and the time of preincubation. Daunorubicin was also shown to inhibit the release reaction, the platelet prostaglandin pathway and the availability platelet factor 3; the drug at concentrations for clinical use does not damage the platelet membrane, as is the case with the freezing and thawing test, in platelet uptake of 14C-serotonin and as confirmed by the electron microscope. When very high doses (0.16 mg) of Daunorubicin are used, lysis of the platelets can be observed and this is confirmed under the electron microscope by the presence of empty platelets with fractures at the level of the cytoplasmid membrane. Finally, Daunorubicin causes irreversible inhibition of reptilase clot-retraction, even if this is less severe than with Vincristine. Working with gel-filtered platelets, it would appear that the inhibition exercised by the drug on platelet reactions is not caused through modifications in Ca++ metabolism. The authors suggest that Daunorubicin, at the dosages used clinically, induces in vitro thrombocytopathy without damaging the cellular membrane as confirmed by the electron microscope. This impairment of platelet functions could play a part in hemorrhagic diathesis observed during Daunorubicin therapy.

Clinical utility of prothrombin fragment 1+2, thrombin antithrombin III complexes and D-dimer measurements in the diagnosis of deep vein thrombosis following total hip replacement.

BACKGROUND: Measurements of prothrombin fragment 1+2 (F1+2), thrombin antithrombin III complexes (TAT) and D-dimer plasma levels have been proposed as non-invasive screening tests to exclude postoperative deep venous thrombosis (DVT). We investigated the diagnostic efficacy of these coagulation activation markers to rule out postoperative DVT in patients undergoing hip surgery under antithrombotic prophylaxis. METHODS: In this substudy of a randomized double-blind thrombosis prophylaxis trial comparing three doses of desirudin (10, 15 or 20 mg b.i.d.) with unfractionated heparin (5000 IU t.i.d.) we used ELISA procedures to measure F1+2, TAT and D-dimer in 159 patients undergoing total hip replacement at baseline (day 0) and on postoperative days 1, 3 and 6. Bilateral venography was performed in all cases 8-11 days after surgery. RESULTS: For the F1+2 assay sensitivity ranged from 73 to 83% in the three postoperative days investigated, and negative predictive value (NPV) from 68 to 74%. For TAT and D-dimer sensitivity ranged from 71 to 73% and from 71 to 83% and NPV from 61 to 65% and from 61 to 74% respectively. INTERPRETATION: In terms of sensitivity and NPV F1+2 and D-dimer are equivalent and are superior to TAT. However, their accuracy is too low to rule out the presence of DVT after hip surgery under antithrombotic prophylaxis.

Effects of fluvastatin and bezafibrate combination on plasma fibrinogen, t-plasminogen activator inhibitor and C reactive protein levels in coronary artery disease patients with mixed hyperlipidaemia (FACT study). Fluvastatin Alone and in Combination Treatment.

AIM OF THE STUDY: We studied the effects of fluvastatin and bezafibrate in monotherapy and in combination on plasma fibrinogen, t-plasminogen activator inhibitor (PAI-1) and C reactive protein (CRP) in patients with coronary artery disease (CAD) and mixed hyperlipidaemia. DESIGN: In this randomised, double blind, multicentre trial 333 patients with stable angina pectoris or previous myocardial infarction or coronary revascularisation and mixed hyperlipidaemia (LDL-cholesterol 135-250 mg/dl and triglycerides (TG) 180-400 mg/dl) were randomised to fluvastatin 40 mg, bezafibrate 400 mg, fluvastatin 20 mg + bezafibrate 400 mg or fluvastatin 40 mg + bezafibrate 400 mg treatments for 24 weeks. RESULTS: Plasma fibrinogen significantly decreased after treatment with the combinations fluvastatin+bezafibrate (-14 and -16%) and with bezafibrate monotherapy (-9%). No significant reduction was observed after fluvastatin monotherapy (-4%). No significant changes were observed in PAI-1 and CRP plasma levels. Combination therapy significantly decreased both LDL-C and TG, and significantly increased HDL-C. CONCLUSIONS: The combined effects on fibrinogen and plasma lipids achieved by fluvastatin and bezafibrate combination treatment might be more useful than the simple reduction of cholesterol in preventing ischaemic cardiovascular disease.

Markers of hemostatic system activation during thromboprophylaxis with recombinant hirudin in total hip replacement.

Coagulation activation markers were studied in 148 patients undergoing total hip replacement under recombinant-hirudin (Desirudin, Revasc) prophylaxis with the aim of investigating the efficacy and safety of this anticoagulant compared with heparin in terms of biological effects on coagulation variables and bleeding. Hirudin (10, 15 or 20 mg s.c. b.i.d.) or unfractionated heparin (5000 IU s.c. t.i.d.) was administered immediately before surgery and continued for 8-12 days. Activated partial thromboplastin time (aPTT), prothrombin activation fragment F1 + 2 (F1 + 2), thrombin-antithrombin III complexes (TAT) and D-dimer were measured at baseline and on postoperative days 1,3 and 6, immediately before the morning injection. In comparison with baseline values, heparin had little effect on aPTT whereas the three hirudin doses prolonged aPTT significantly with no differences among the three doses. Moreover, there were no group differences in perioperative or cumulative blood loss or transfusion requirements. F1 + 2 fragment, TAT and D-dimer plasma levels were higher than at baseline during the entire postoperative period, with different trends (F1 + 2 increasing, TAT decreasing, D-dimer increasing, decreasing and then increasing again), but without significant differences among the four treatment groups. Our findings suggest that specific inhibition of thrombin seems a safe and efficacious mode of blocking thrombin activity after hip surgery although it does not prevent thrombin generation.

Association of increased fibrin turnover and defective fibrinolytic capacity with leg atherosclerosis. The PLAT Group.

Patients with peripheral arterial disease have a high risk of death from cardiovascular events. As defective fibrinolysis associated with leg atherosclerosis has been suggested as a predisposing factor, we sought a relation among decreased fibrinolysis, the presence of leg atherosclerosis and the incidence of thrombotic events in a case-control study nested in the PLAT. Fifty-eight patients with coronary and/or cerebral atherothrombotic disease, free of leg atherosclerosis at Doppler examination, were compared with 50 atherosclerotic patients with leg involvement. High D-dimer (153.0 vs 81.3 ng/ml, p < 0.001) and tPA antigen before venous stasis (14.4 vs 11.8 ng/ml, p < 0.03), and low tPA antigen (6.7 vs 15.6 ng/ml, p < 0.01) and fibrinolytic activity released after venous stasis (fibrinolytic capacity: 113.2 vs 281.4 mm2, p < 0.001) were found in patients with leg atherosclerosis. D-dimer and fibrinolytic capacity, in addition to age, were selected by stepwise discriminant analysis as characterizing patients with leg atherosclerosis. Moreover, higher D-dimer and tPA inhibitor characterized patients with leg atherosclerosis who subsequently experienced thrombotic events. These findings constitute evidence of high fibrin turnover and impaired fibrinolytic potential in patients with leg atherosclerosis. Thus impaired fibrinolysis may contribute to the prothrombotic state in these patients.

Primary shunt hyperbilirubinemia associated with Gilbert's syndrome.

A patient with primary shunt hyperbilirubinemia associated with Gilbert's syndrome is described. The laboratory findings of unconjugated hyperbilirubinemia, mild reticulocytosis, normoblastic erythroid hyperplasia of bone marrow, increased plasma iron turnover, and normal peripheral red blood cell survival were consistent with increased intramedullary hemolysis. Nevertheless, unconjugated bilirubin level exceeding 4 mg/100 mL, in the absence of appreciable anemia and of biochemical evidence of hepatic dysfunction, suggested the coexistence of defective hepatic bilirubin clearance. The mode of inheritance and the effect of fasting and phenobarbital on bilirubin concentrations were indicative of associated Gilbert's syndrome.

The effect of dermatan sulfate on in vitro human plasma coagulation, platelet aggregation and beta TG/PF4 release.

We evaluated the in vitro anticoagulant action of dermatan sulfate (DS) (aPTT, antiXa, anti-thrombin) and its effect on human platelet aggregation and beta TG/PF4 release induced by threshold doses of aggregating agents, compared with standard heparin (SH). In pooled plasma, DS prolonged aPTT much less than SH, had no measurable antiXa activity, showed an anti-thrombin activity similar to that shown by SH at a tenfold higher dilution. DS had no direct effect on human platelet aggregation and beta TG/PF4 release. Moreover it did not significantly affect platelet aggregation and release by ADP and collagen, whereas it completely inhibited platelet aggregation and beta TG/PF4 release by thrombin. These data in vitro confirm that thrombin inhibition induced by DS is accompanied by a far lesser aPTT prolongation compared to heparin, without any appreciable interference with platelet function.

Dermatan sulphate for the treatment of disseminated intravascular coagulation (DIC) in acute leukemia: a randomised, heparin-controlled pilot study.

Efficacy and safety of i.v. dermatan sulphate (DS) and heparin (H) in controlling laboratory alterations due to DIC were compared in 10 patients with acute leukaemia, in a prospective, randomised pilot study. The time courses of the coagulation and fibrinolysis markers for DIC were similar in the two treatment groups except for activated partial thromboplastin time and thrombin time, which were prolonged in the H but not in the DS group. Blood product support tended to be greater in the H than in the DS group. DS appears to be as effective as H in controlling thrombin production during leukaemic cytolysis and may represent a safer alternative to H in the management of DIC in acute leukaemia.

Association of lipoprotein(a) with atherothrombotic events and fibrinolytic variables. A case-control study.

Elevated plasma levels of lipoprotein(a) [Lp(a)] have been associated with an increased risk of cardiovascular disease. The aim of the present study was to investigate whether Lp(a) plasma levels were associated with subsequent ischemic events and with fibrinolytic variables in patients with established atherosclerotic disease enrolled in the prospective PLAT study. Lp(a) levels and fibrinolytic variables in 37 atherosclerotic patients who subsequently developed an atherothrombotic event during the first year of follow-up (cases) were compared with those in paired controls, matched for age, sex, diagnosis at enrollment and lipid pattern, who remained free from vascular events during the same time frame. Median and mean Lp(a) levels were similar in cases (6.05 mg/dl; 13.8 +/- 19.4 mg/dl) and controls (6.05 mg/dl; 17.1 +/- 21.6 mg/dl). In the whole group plasma Lp(a) levels correlated significantly with the increase of t-PA antigen (r = 0.368; p = 0.002) and fibrinolytic activity (r = 0.410; p = 0.001) induced by venous stasis but not with baseline fibrinolytic variables. These findings indicate that in patients with established atherosclerotic disease Lp(a) may interfere in vivo with the fibrinolytic process but is not predictive of subsequent ischemic events.

Low-dose heparin in thoracic surgery: effect on blood coagulation and fibrinolysis system.

Plasma kallikrein, antithrombin III and antiplasmin were determined with chromogenic methods in 29 patients pre-, per- and post-operatively in a controlled, randomized study. 16 patients received calcium heparin, 5000 IU s. c. every 8 hr for 7 days, the first administration given 2 hr before surgical procedure. 13 control patients received saline. A significant reduction of kallikrein and antiplasmin in per- and post-operative periods was observed in the control patients compared with the heparin-treated patients, while there was a significant reduction of anti-thrombin III in the control patients compared with the treated patients only in the per-operative period. The results obtained suggest that activation of the coagulation and fibrinolysis system occurs in patients undergoing thoracic surgery, and that it is inhibited significantly by calcium heparin prophylaxis.

High heparin released platelet factor 4 in uncomplicated type 1 diabetes mellitus.

The role of platelet activation in diabetic microangiopathy is still controversial. We evaluated the degree of platelet activation in relation to vessel wall damage in three selected, well matched groups of subjects (10 healthy controls; 20 insulin dependent diabetic patients, 10 without microangiopathy and 10 with microangiopathy). We measured beta TG and PF4 plasma levels before and 5, 15 and 90 min after a heparin bolus i.v. (5000 U). beta TG basal levels were increased only in diabetic patients with microangiopathy. Diabetic patients without microangiopathy showed significantly higher levels of heparin released-PF4 (HR-PF4) in comparison with healthy controls. High levels of HR-PF4 seem to be an early marker of in vivo increased platelet activation in uncomplicated diabetes mellitus.

[rt-PA in extracardiac thromboembolic vascular occlusions]. / L'rt-PA nelle occlusioni vascolari trombo-emboliche extra-cardiache.

Recombinant tissue plasminogen activator (rt-PA) is a thrombolytic agent characterized by elevated but not absolute fibrin specificity. However, its therapeutic dose is high and associated with a variable degree of systemic activation of the fibrinolytic system. Thrombolytic drugs are widely used in acute myocardial infarction and have now begun to be considered for deep vein thrombosis (DVT), pulmonary embolism (PE), and peripheral artery thrombosis (PAT) as well. Although anticoagulant therapy is effective in reducing the immediate complications of venous thromboembolism, thrombolytic therapy has various advantages over anticoagulant therapy, including lysis of thrombi with recanalization of venous circulation, reduction of venous valve damage and prevention of post-phlebitic syndrome. The different dosage regimens of rt-PA recently evaluated (0.71 to 1.76 mg/kg/24 h for 2-4 days) in DVT have caused consistent thrombolysis but also excessive bleeding. The optimal therapeutic range for rt-PA in DVT remains to be determined. Thrombolytic therapy is superior to heparin treatment only in hemodynamically compromised patients with massive PE. The minor systemic fibrinolytic effect and the faster action on thrombi of rt-PA compared with the first generation thrombolytic agents, streptokinase (SK) and urokinase (UK), are very interesting and explain the positive results recently obtained in PE with this drug (50 mg over 2 h, followed, if necessary, by 40-50 mg over 4-5 h) by Goldhaber and Verstraete.(ABSTRACT TRUNCATED AT 250 WORDS)

Preoperative plasma levels of prothrombin fragment 1 + 2 correlate with the risk of venous thrombosis after elective hip replacement.

Better preoperative identification of those patients at high risk of developing a deep vein thrombosis (DVT) after hip surgery could reduce the incidence of this postoperative complication, which still occurs despite prophylaxis. One hundred fifty-nine patients undergoing elective total hip replacement and given anticoagulant prophylaxis, were investigated, looking for the presence of a hypercoagulable state, that represents one element of Virchow's triad predisposing to DVT. Plasma levels of three markers of coagulation activation, namely prothrombin fragment 1 + 2 (F1 + 2), thrombin-antithrombin III complexes (TAT) and D-dimer were measured using ELISA procedures and were correlated with the results of the postoperative phlebography. A high correlation (p < 0.001) between the preoperative plasma levels of F1 + 2 and the risk of postoperative venous thromboembolism was detected. The performance of TAT and D-dimer levels in predicting DVT was lower. These findings support the hypothesis that preoperative measurement of coagulation activation markers might be useful in predicting DVT following a total hip replacement.