Alpha 2-plasmin Inhibitor Research Articles

Anticoagulation during use of a left ventricular assist device.

Thirty-six mongrel dogs underwent 24hr left ventricular assist. The VAD was placed between the left atrium and the descending aorta, and the dogs were divided into four groups according to type of anticoagulation: no anticoagulation, argatroban, nafamostat mesylate, and nafamostat mesylate + prostacyclin analog. Results of this animal experiment revealed that a newly developed synthetic thrombin inhibitor argatroban can prevent activation of the intrinsic coagulation pathway. Argatroban is efficient under any blood coagulative condition, even lack of anti-thrombin III, because of its direct inhibitory effect on thrombin, making argatroban more useful than heparin as an anticoagulant for LVAD. Argatroban, as well as heparin, provides marked and significant prolongation of the prothrombin time from early assisted circulation, but produces a bleeding tendency. Nafamostat mesylate can maintain blood coagulation parameters within the acceptable range. Combined administration of nafamostat mesylate and a prostacyclin analog cause the least decrease in fibrinogen and alpha2-plasmin inhibitor among the four groups and causes no significant prolongation of prothrombin time.

Immunohistochemical analysis of vascular prostheses implanted with the left ventricular assist system

Background Dacron vascular prostheses are associated with thromboembolic complications and inflammatory responses; impregnation with bovine collagen reportedly stimulates additional inflammatory/immunologic complications. The Novacor (Baxter Healthcare Corp., Oakland, CA, USA) left ventricular assist system uses Dacron inflow and collagen-impregnated Dacron outflow prostheses. Methods Explanted inflow and outflow prostheses were evaluated for inflammatory/immunologic, hemostatic, anticoagulant, and fibrinolytic pathways. Non-implanted prostheses immersed in whole blood or plasma were used as controls. Results Immunoglobulins and complement components were observed in all prostheses with activated macrophages being present only in implanted prostheses. Antithrombin III was observed in all prostheses whereas fibrin, tissue plasminogen activator, and alpha-2 plasmin inhibitor were present only in implanted prostheses. Endothelial and smooth muscle cells associated with vascular structures containing collagen type IV and laminin were observed solely in implanted prostheses. Conclusion An inflammatory response occurs and key components of hemostatic, anticoagulant, and fibrinolytic pathways are present within implanted prostheses. These processes are accompanied by endothelial and smooth muscle cell infiltration which appear to lay the foundation for neovessel development.

The effects of recombinant tissue-type plasminogen activator (rt-PA) on canine cadaver lung transplantation.

The intrapulmonary thrombi that form after the cessation of circulation are thought to be one of the major causes of graft function failure. We evaluated the effect of recombinant tissue-type plasminogen activator (rt-PA) in a canine cadaver lung transplant model. Donor dogs were killed by the intravenous administration of pancuronium bromide without heparinization, and left for 2 h at room temperature. The donor lungs were then flushed with low potassium dextran glucose (LPDG) solution, being subjected to a total ischemic time of 3 h. Following left lung transplantation, the contralateral pulmonary artery of the recipient dogs was ligated. In group 1 (n = 6), chloride solution was administered from the main pulmonary artery for 90 min, commencing 15 min prior to reperfusion. In group 2 (n = 6), 2.5 microg/kg per min of rt-PA, and in group 3 (n = 6), 5.0 microg/kg per min of rt-PA, were continuously infused in the same manner as in group 1. Lung function, including arterial blood gases and pulmonary hemodynamics, was measured for 3 h. The side effects of rt-PA were evaluated by measuring the prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen, alpha2-plasmin inhibitor (alpha2-PI), plasminogen, and fibrin/fibrinogen degradation product (FDP). All of the animals in the three groups survived throughout the observation period. The group 3 animals had significantly better gas exchange than the group 1 animals, and the pulmonary hemodynamics were significantly better in the group 2 and 3 animals than in the group 1 animals. The FDP levels in the group 2 and 3 animals were significantly higher than those in the group 1 animals, while the PT and APTT were significantly prolonged in the group 3 animals. These findings led us to conclude that rt-PA improves early lung function, particularly pulmonary hemodynamics.

Coagulation and fibrinolytic activity in rats with naturally occurring gingivitis.

It is well known that there are several coagulation factors and fibrinolysis factors, and these inhibitors are also present in blood and tissues. Normally, these factors balance each other. We measured antithrombin III (AT III), an important inhibitor of coagulation and alpha 2-plasmin inhibitor (alpha 2-PI), a factor inhibiting fibrinolysis in blood and gingival tissue of naturally occurring gingivitis rats (ODUS/Odu) and control rats (Res). Blood plasma and supernatants of gingival homogenate from ODUS/Odu and Res were used as samples. And concentrations of alpha 2-PI and AT III were measured by colorimetric assay using commercially available reagents. We found no difference in blood concentrations of alpha 2-PI or AT III between ODUS/Odu and Res groups. However, AT III in the gingiva showed a significantly higher value in the ODUS/Odu group versus that in the controls (p < 0.001). There was a high positive correlation between AT III in gingival tissue and pocket probing depth. Moreover, the fibrinolytic activity in saliva and the gingiva from ODUS/Odu increased with each passing month. Results suggest that both the decrease in blood coagulability and systemic enhancement of fibrinolytic activity due to increased AT III in gingival tissue are associated with the bleeding tendency and inflammatory response in the gingiva of ODUS/Odu.

Cross-linking exogenous bifunctional peptides into fibrin gels with factor XIIIa.

Bi-domain peptides with a factor XIIIa substrate in one domain and a bioactive peptide in another domain were covalently incorporated into fibrin gels during coagulation through the action of the transglutaminase factor XIIIa. The cross-linking characteristics were determined for two bi-domain peptides with factor XIIIa substrates based on fibrinogen, dYRGDTIGEGQQHHLGG-NH2, and dLRGDGAKDV-NH2, as well as one bi-domain peptide with a substrate sequence based on alpha2-plasmin inhibitor, dLNQEQVSPLRGD-NH2, and another with a nonbiological, oligolysine substrate, dLRGDKKKKG-NH2 (substrate domains in italic). Each of these peptides was able to cross-link into the fibrin gels during coagulation, with the peptide containing the factor XIIIa substrate based on alpha2-plasmin inhibitor being incorporated at levels in excess of 8 mol/mol fibrinogen. The structural characteristics of these peptide-modified gels proved to be the same as those for a native fibrin gel. The bioactivity of the incorporated active factors was tested in a neuronal culture model with day 8 chicken dorsal root ganglia using two bioactive sequences, RGD and DGEA, and one inactive control sequence, RDG. Each of these peptides influenced the extension of neurites from the ganglia as expected, indicating that the incorporated factors retained their activity. With the use of soluble competitive inhibitors, it was shown that this effect was due to the covalently incorporated peptides. Through exploiting the role of factor XIIIa in coagulation, we have developed a method by which to impart the character of nonfibrin proteins, such as extracellular matrix proteins, to fibrin, a biological material with many potential therapeutic and academic applications.

Age-related changes in blood coagulation and fibrinolysis in mice fed on a high-cholesterol diet.

To investigate the pathogenesis of hyperlipidemia-induced atherosclerosis, we examined age-dependent changes in platelet activity, blood coagulation and fibrinolysis in susceptibility to a high cholesterol diet (HCD) feeding in male ICR mice. Pretreatment of platelet-rich-plasma from HCD feeding mice for 3 days with epinephrine (300 microM) resulted in a marked enhancement of adenosine 5'-diphosphate (ADP: 0.1 microM) or collagen (0.7 microgram/ml)-stimulated aggregation compared with the same in control mice. Yohimbine as alpha 2-adrenergic blocker antagonized these aggregations in a dose-dependent manner. A significant increase in plasma total cholesterol and VLDL (very low-density lipoprotein)-LDL (low-density lipoprotein)-cholesterol and the liver/body weight ratio was observed in mice fed on HCD for 3 months (3-month HCD mice). In the early phase of this experiment, a significant increase in fibrinogen was observed. In the middle phase, increases in the activity of antithrombin III (ATIII) and alpha 2-plasmin inhibitor (alpha 2-Pl) followed. Plasminogen content gradually decreased in both normal diet and HCD mice throughout the experiment. The activity of plasminogen activator inhibitor (PAI) decreased in 3-month HCD mice. Morphological observation of the aortic arch from 3-month HCD mice revealed apparent atheromatous plaques not seen in control mice. These results suggest that 3-month HCD mice can be a convenient hyperlipidemia-induced atherosclerotic model and the changes in platelet activity, coagulation and fibrinolysis in the early phase may be a cause of pathologic changes in this model.

Severe Postadenoidectomy Bleeding Revealing Congenital alpha2 Antiplasmin Deficiency in a Child

Severe Postadenoidectomy Bleeding Revealing Congenital alpha2 Antiplasmin Deficiency in a Child

Hypercoagulable state in a hypobaric, hypoxic environment causes non-bacterial thrombotic endocarditis in rats.

High-altitude hypoxia causes polycythaemia and a hypercoagulable state in humans and animals. This study examines the effects of a hypobaric, hypoxic environment (HHE) on the blood coagulation system in rats. A total of 170 male Wistar rats were housed in a chamber at the equivalent of 5500 m in altitude for 1-12 weeks. After 2 weeks of exposure to HHE, platelet counts decreased significantly; after 4 weeks, the prothrombin and activated partial thromboplastin times were significantly prolonged, compared with those of control rats. In addition, individual coagulation factors (VII, IX, X, XI, and XII) were significantly decreased at 8 weeks (P < 0.05). Levels of anti-thrombin III and alpha 2-plasmin inhibitor also decreased (between 4 and 8 weeks). After 4-12 weeks of exposure to HHE, 30 of 56 rats (54 per cent) developed (i) non-bacterial thrombotic endocarditis (NBTE) or (ii) infarction of the myocardium or kidney, or both (i) and (ii). The incidence of NBTE increased from 33 per cent (5/15 rats) at 4 weeks to 100 per cent (7/7 rats) at 12 weeks. Electron microscopy showed detached endothelial cells in the mitral valves at 1 week; platelets adhered to the subendocardial matrix and platelet aggregation with thrombus formation was seen at 2 weeks of exposure. The results suggest that exposure to HHE induces a hypercoagulable state and causes an NBTE in rats that may result in consumption coagulopathy.

Electrophoretic demonstration of high molecular weight fibrin degradation products persisting in chronic subdural hematomas.

Local hyperfibrinolysis plays an important role in the pathogenesis of chronic subdural hematoma (CSH). The purpose of this study is to elucidate the nature of the local hyperfibrinolysis in CSH, by comparing the pattern of fibrin/fibrinogen degradation product (FDP) of hematomas with that of purified fibrin clots digested by plasmin in vitro. Forty-seven hematoma samples were subjected to the analysis. FDPs of CSH and the purified fibrin clots digested by plasmin for different incubation times were identified using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and immuno-blotting, and then quantified by densitometry. The effect of alpha-2 plasmin inhibitor (A2-PI) on the degradation process was also studied. The FDP pattern of CSH was similar to those of purified fibrin digested by plasmin for 0.75-2 h. The FDP composition of CSH was closest to that of purified fibrin digested for 1 h. By adding the physiological concentration of A2-PI at the second hour, further degradation of high molecular weight FDPs was inhibited and the early FDP pattern persisted after 24 h. Local hyperfibrinolysis in CSHs is characterized by incomplete fibrinolysis, which occurs only on the solid fibrin clot, and is arrested in the liquid hematoma. As a result, high molecular weight FDPs persist in CSHs for weeks or months in the hematoma. A2-PI seems to play an important role in producing this unique FDP pattern in CSH.

Hypercoagulability and secondary hyperfibrinolysis may be related to abnormal lipid metabolism in patients treated with continuous ambulatory peritoneal dialysis.

To investigate abnormalities in the hemostatic and fibrinolytic system in CAPD patients, parameters of coagulation, anticoagulation, fibrinolysis, and platelet function were measured in 21 CAPD patients and 20 healthy controls. The CAPD patients had significantly higher levels of factor (F) IX, FVII, FX, antithrombin III, thrombin/antithrombin III complex, protein C, protein S, thrombomodulin, fibrinogen, fibrinopeptide A, plasminogen, FXIII, alpha2-plasmin inhibitor, alpha2-plasmin inhibitor/plasmin complex, D-dimer, fibrinopeptide B beta 15-42, and beta-thromboglobin than the healthy controls. The CAPD patients also showed a shorter prothrombin time. However, tissue plasminogen activator, plasminogen activator inhibitor-1 and platelet factor-4 did not show any significant differences from the levels in healthy controls. There was a significant positive correlation between many of the blood parameters and serum lipids. These results demonstrate that hypercoagulability and secondary hyperfibrinolysis occur in CAPD patients, and suggest that these changes may be related to abnormalities in lipid metabolism.

Blood coagulability and fibrinolysis in streptozotocin-induced diabetic rats.

Changes in coagulation and fibrinolysis in the plasma (in vivo) and hepatocytes (ex vivo) were studied using hyperglycemic rats. Hyperglycemia was induced by intravenous injection of 50 mg/kg streptozotocin (STZ). Eight weeks after the injection, we observed increases in thrombin-antithrombin III complex and tissue type plasminogen activator activity, decreases in plasma levels of antithrombin III, plasminogen and alpha2-plasmin inhibitor, and significant shortening of activated partial thromboplastin time. In freshly isolated or cultured hepatocytes from STZ-induced hyperglycemic rats, concentrations of proteins related to coagulation were increased. An increase in alanine-aminotransferase leakage and decreases in the levels of amylase, triglycerides and phospholipids were observed in the culture medium of hepatocytes from STZ treated rats. In vivo study revealed that STZ-induced subchronic diabetes induced imbalance between coagulation and fibrinolysis, and ex vivo study in hepatocytes from STZ-treated rats showed membrane degeneration and reduction in amylase synthesis, while protein synthesis related to coagulation was not inhibited. These results suggest that, despite vulnerability of liver cells from STZ treated rats, coagulation activity in the liver is retained and rather enhanced in STZ-induced hyperglycemic rats, which may contribute to the promotion of atherosclerosis.

Interleukin-6 is a useful marker for early prediction of the severity of acute pancreatitis.

Twelve patients with acute pancreatitis admitted to our department between January 1993 and December 1994 were studied prospectively and classified into two groups (severe group, five patients; mild group, seven patients), according to the criteria for grading severity of acute pancreatitis proposed by the Research Committee for Intractable Diseases of the Pancreas, Japanese Ministry of Health and Welfare (1990). To evaluate markers for early estimation of the severity of acute pancreatitis, we measured serum changes in various parameters. In the severe group interleukin-6 (IL-6) levels were increased significantly 5, 24, 72, and 120 h after the onset (p < 0.01), compared with the mild group. C-reactive protein (CRP), thrombin antithrombin III, and alpha 2-plasmin inhibitor plasmin complex levels were significantly increased only at the 72-h time point. Peak values of interleukin-8 (IL-8) and soluble human E selectin were observed at 5 and 72 h, respectively, after the onset. There was a significant correlation between IL-6 at 5 h and both pancreatic secretory trypsin inhibitor (r = 0.85) and CRP (r = 0.94) at 72 h. We therefore conclude that IL-6 is a useful marker for assessment of the severity of acute pancreatitis in its early stages.

The fibrinolytic system in neoplasia.

During activation of the fibrinolytic system plasminogen is converted to plasmin by tissue plasminogen activator (t-PA) or urokinase-type plasminogen activator (u-PA). t-PA is predominantly released from endothelial cells, u-PA primarily by renal parenchymal cells. The activation of plasminogen is regulated by plasminogen activator inhibitor-1 (PAI-1), plasmin is controlled by alpha 2-plasmin inhibitor. The fibrinolytic system is not only involved in the intravascular dissolution of fibrin (thrombi), it also plays a vital role in normal physiologic reproduction, wound repair, angiogenesis, and tissue remodeling. Fibrinolysis is also a vital component in the pathogenesis of neoplastic disease. It is essential in releasing cells from their primary site of origin, providing nutrition for neoplastic cell growth and promoting cell mobility and motility. In neoplastic cells the degradation of the extracellular matrix proteins is facilitated by excessive expression of u-PA, t-PA, and u-PAR. In many forms of carcinoma increased expression of u-PAR and u-PA is associated with significantly shorter survival. Greater expression of u-PA in breast cancer cells, for example, is associated with shorter survival and increased relapse rate. Progressively aggressive neoplastic cells evidence high expression of u-PA and u-PAR activities, variable expression of t-PA, and enhanced PAI-1 and PAI-2 activities. In acute nonlymphocytic leukemias, poor outcome correlates with high t-PA levels. In acute progranulocytic leukemia there is a high incidence of DIC. Neoplastic prostatic tissue also expresses high u-PA activity and the more aggressive the cell line, the greater the number of u-PAR and the higher the u-PA activity. In gynecologic malignancies, a greater expression of u-PA in combination with cathepsin D is associated with widespread disease and poor prognosis. High u-PA values were also seen in patients with brain, gastric, and hepatic malignancies. It is evident that the plasminogen-plasmin system is a vital component in the biology of neoplastic disease and that it is, in theses conditions, in no way beneficial to the host.

Factors that control extravascular fibrinolysis.

The physiological and pathophysiological state of tissues determines the exudation of plasma proteins, hemostasis, and fibrinolysis, i.e., inflammation, injury, and malignancy. The physiological controls of extravascular fibrinolysis ultimately rest on a balance between generation of the fibrinolytic enzyme(s), i.e., plasmin, elastase, cathepsins, etc., and inhibitors of the fibrinolytic enzyme(s), i.e., plasminogen activator inhibitors, alpha-2 plasmin inhibitor, alpha 1-protease inhibitors, etc. Moreover, it is the structural modification of fibrin that determines its stability toward proteolytic enzymes and physical duress. The structural modification of fibrin involves factor XIIIa-mediated cross-linking of interfibrin chains and alpha 2-plasmin inhibitor to fibrin. In turn, there are a number of agents that influence factor XIIIa catalytic activity (e.g., sulfhydryl agents, albumin, erythrocytes). The two key proenzymes, factor XIII and plasminogen, are tightly bound with the circulating fibrinogen molecules. Such high selective affinity for fibrin(ogen) provides the reaction specificity in a complex tissue fluid milieu and governs the kinetics of fibrinolysis. Any agents that interfere with such binding reactions, e.g., autoantibodies, may also affect the fibrinolytic reactions. Understanding these unique biochemical controls of factors involved in fibrinolysis may provide an insight into the complex regulatory process of extravascular fibrinolysis.

Fibrin degradation in the synovial fluid of rheumatoid arthritis patients: a model for extravascular fibrinolysis.

The patterns of degradation and the influence of factor XIII polymerization on fibrin stability were examined in vitro following incubation with leukocyte elastase. In vivo experiments, various factor XIII-polymerized fibrin clots were implanted subcutaneously in mice to evaluate the stability of clots in the extravascular space. Both in vitro and in vivo lysis proceeded faster with nonpolymerized fibrin and was not influenced by the presence of cross-linked alpha 2-plasmin inhibitor. In vivo lysis of implanted clots was prevented by elastatinal, powerful elastase inhibitor, suggesting that granulocyte elastase is chiefly responsible for clot lysis in the extravascular space. To further extend investigations on the mechanisms of fibrinolysis in tissues, we evaluated fibrin and its degradation products in the synovial space. Expression of factor XIII in synovial cells and activities of coagulation factors, fibrinolytic enzymes, and inhibitors were investigated in the synovial fluid of rheumatoid arthritis patients. Immunohistochemical analysis showed deposits of insoluble fibrin on synovial membranes and pannus to an extent related to the progression of the disease. Factor XIII was expressed by fibroblasts and macrophages in the early stages of the disease, whereas in advanced stages factor XIII staining was associated with fibrin. The reduction of certain coagulation factors and high level of thrombin-antithrombin complexes in synovial fluid show a steady activation of the coagulation cascade. The evaluation of fibrinogen degradation products and the pattern of degradation of synovial fibrin(ogen) suggest the participation of leukocyte elastase in fibrin(ogen) lysis in synovial tissue of rheumatoid arthritis.

Nafamostat mesilate reduces blood-foreign surface reactions similar to biocompatible materials

Nafamostat mesilate (FUT-175) is a synthetic serine protease inhibitor that inactivates coagulation, fibrinolysis, and platelet aggregation. Nafamostat mesilate may suppress the blood-foreign surface reaction similar to biocompatible materials by blocking factor XIIa. We performed an in vitro study of cardiopulmonary bypass (CPB) with fresh human blood among the following three groups: standard CPB sets (C), biocompatible CPB sets (B), and standard CPB sets with FUT-175 (10 mg/L) (F). A clinical study using these same CPB groups also was performed in 45 patients undergoing aortocoronary bypass operations (15 patients each). We injected FUT-175 at 40 mg/h during CPB. In the in vitro study, both groups B and F showed significantly lower levels of coagulation factors, thrombin-antithrombin III complex, fibrinopeptide A, beta-thromboglobulin, complement C3a, granulocyte elastase, and free hemoglobin than group C at the conclusion of the study. Thrombin-antithrombin III complex and free hemoglobin in group F also were lower than in group B. The platelet count remained at a higher level in group F than in the other groups. Separation of bradykinin was suppressed most significantly in group F. In the clinical study, group F also showed significantly lower levels of alpha 2-plasmin inhibitor plasmin complex and C3a than both groups C and B. There were minimal levels of free hemoglobin in group F. Nafamostat mesilate may contribute major beneficial effects toward conservation of blood during CPB and prevention of coagulopathy after CPB.

Determinants of substrate specificity for factor XIII.

Plasma factor XIIIa (A*2) is a regulator in balancing the opposing coagulation and fibrinolytic processes. Its enzymatic activity is to catalyze epsilon-(gamma-glutamyl)lysyl bonds between certain substrate molecules to link them by strong bonds. The primary physiological substrates are crosslinks between the gamma and alpha chains of fibrin that produce gamma-gamma-dimer and alpha-polymer, between alpha 2-plasmin inhibitor (alpha 2-PI) and alpha chains of fibrin, and between fibronectin and fibrin. We have characterized a unique factor XIII antibody that is specific for the middle 54-kDa section of A*2. It does not react with the zymogen (A2) or the inactive intermediate (A'2), and it does not inhibit the active center, as do most patient antibodies to factor XIII. This antibody inhibits the formation of A*2-fibrin complexes. Because of this specificity, the antibody was used to study other substrate interactions. It inhibited formation of fibronectin-factor XIIIa complexes, similarly to fibrin, and there was very little crosslinking of fibronectin to a fibrin clot. However, the amount of alpha 2-PI crosslinked to a fibrin clot was normal. It was concluded that this antibody interferes with exosite binding of fibrin and fibronectin interferes with exosite binding of fibrin and fibronectin in a similar way, while at least one critical exosite binding domain for alpha 2-PI is different from those of the other two substrates. Furthermore, with this antibody, it was shown that both alpha 2-PI-alpha chain crosslinking and alpha-polymer formation are necessary to normalize the rate of fibrinolysis.

Thrombin-antithrombin III complexes as an additional diagnostic aid in pulmonary embolism.

Plasma levels of selected coagulation and fibrinolytic parameters (activated partial thromboplastin time, prothrombin time, fibrinogen, antithrombin III, protein C, thrombin-anti-thrombin III complexes (TAT), plasminogen activator inhibitor-1 (PAI-1), plasminogen, alpha 2-plasmin inhibitor) were evaluated in 90 patients with clinical suspicion of pulmonary embolism (PE). Plasma levels of fibrinogen, PAI-1 and TAT were significantly higher in patients than in controls (p < 0.01): evaluation of TAT displayed a sensitivity of 96.1% and specificity of 30.8%, and positive and negative predictive values of 64.5 and 85.7%, respectively. The number of nonperfused lung segments correlated directly with TAT levels (p < 0.01) and inversely with arterial pO2 values (p < 0.01). No significant difference was found in the other parameters between patients and controls. Our results suggest that the finding of normal TAT plasma levels can help to exclude PE in patients with clinically suspected PE.

Danger of urokinase as an anticoagulant with left ventricular assist devices.

The sole administration of urokinase causes no initial prolongation of activated partial thromboplastin time (A-PTT), but thereafter produces serious progressive prolongation of A-PTT; it also causes a progressive, severe decrease in fibrinogen levels and alpha 2-plasmin inhibitor activity by depletion. The antithrombogenicity of urokinase is not caused by prevention of blood coagulation system activation by antithrombin effect, but by secondary fibrinolysis by plasmin. Consequently, the administration of urokinase as a sole anticoagulant results in activation of coagulation and fibrinolysis, and, as a result, induces disseminated intravascular coagulation. Therefore, it is concluded that administration of urokinase is an inadequate anticoagulation therapy unless it is combined with other antithrombin agents.

Changes in coagulation and fibrinolytic system after local intra-arterial thrombolysis for acute ischemic stroke.

Intracerebral hemorrhagic transformation is one of the most important complications of thrombolytic therapy for acute ischemic stroke. The relationship between changes in markers for the coagulation and fibrinolytic systems and occurrence of hemorrhagic transformation was determined after local intra-arterial thrombolytic therapy using urokinase (UK) (24 patients) or recombinant tissue plasminogen activator (t-PA) (10 patients) within 6 hours of onset. All 34 patients had no hypodensity areas on initial computed tomography scans. Plasma concentrations of fibrinogen-fibrin degradation products (FDP), fibrinogen, alpha 2-plasmin inhibitor (alpha 2-PI), plasmin-alpha 2 plasmin inhibitor complex (PIC), thrombin-antithrombin III complex (TAT), and D-dimer were measured. Hemorrhagic transformation occurred in seven patients (21%) with complete or partial recanalization; four in the UK group and three in the t-PA group. Doses of the thrombolytic agents did not correlate with the incidence of hemorrhagic transformation. The FDP levels in the hemorrhagic transformation group treated with UK significantly increased immediately and 1 hour after the therapy. The alpha 2-PI activities decreased and PIC levels increased in both the hemorrhagic transformation and the nonhemorrhagic groups after the therapy. The TAT levels in both groups tended to be higher than the normal range, but there was no significant difference from the pretreatment levels. The D-dimer levels in the hemorrhagic transformation group were higher than those in the nonhemorrhagic group at 24 hours after the therapy. Furthermore, the D-dimer levels were significantly higher in patients with complete recanalization compared with those with none or partial recanalization.(ABSTRACT TRUNCATED AT 250 WORDS)