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PubMed2006

Hypercoagulability: interaction between inflammation and coagulation in familial Mediterranean fever.

Familial Mediterranean fever (FMF) patients in clinical remission are reported to have increased baseline inflammation. Normal function of the natural anticoagulant pathways is particularly needed in diminishing inflammatory responses. In the presence of subclinical inflammation, natural anticoagulant response may be exaggerated. We aimed to observe the anticoagulant-procoagulant status in attack-free FMF patients. Twenty-seven FMF patients diagnosed in accordance with Tel-Hashomer criteria, and 26 healthy controls were included. All patients were attack-free under regular colchicine treatment. Amyloidosis, autoimmunity, accompanying liver and renal disease, and vasculitis were excluded. Predisposing factors for thrombosis were not present. Acute phase reactants (APRs), anticardiolipin antibody positivity, prothrombin time (PT), activated prothrombin time, thrombin time (TT) and d-dimer, protein C activity, activated protein C resistance, free protein S, antithrombin, lupus anticoagulant, human prothrombin fragment F 1 + 2, and human thrombin/antithrombin III complex were analyzed for all subjects. APRs were comparable with controls. Autoimmune markers were negative in all. Anti-streptolysin titers were significantly different than the control group. PT, TT, protein C activity, and F 1 + 2 levels were significantly different from those of healthy controls. Shortened PT and TT, decreased protein C activity vs increased levels of F 1 + 2 suggested a hypercoagulable state in our patients. The hypercoagulable state detected in FMF patients suggests that screening with abnormal coagulation tests may be beneficial for tracing the future consequences of subclinical inflammation in these patients. Studies covering larger groups of patients are needed to verify the currently observed hypercoagulable status in FMF.

Adolescent↗
PubMed1997

[Prevalence of hypercoagulation conditions in patients with thrombosis in Northern Navarra].

BACKGROUND: To determine the prevalence of hypercoagulability states in patients with thromboembolic disease in Septentrional Navarra. PATIENTS AND METHODS: 74 patients were studied (13 female, mean age [+/- SD] 43.5 +/- 13.9 years, range 22-81) with: deep venous thrombosis (DVT) with or without pulmonary embolism (PE) in 15 patients; ischemic stroke (IS) in 20 patients and; myocardial infarction (MI) in 39 patients. Antithrombin III, C protein (CP), plasminogen, plasminogen activator inhibitor (PAI), total S protein (TSP), free S protein (FSP), lupus anticoagulant (LA) and anticardiolipin antibodies (ACA) type IgG were determined in all patients. RESULTS: The prevalence of hypercoagulability state was 27% in patients with thromboembolic disease; 26.6% in patients with PE (20% with ACA and 6.6% with CP deficiency); 30% in patients with IS (15% with ACA, CP deficiency in 5%, FSP deficiency in 5%, and PAI raising in 10%) and in the 25.6% of patients with MI (15.3% with ACA, 2.5% with CP deficiency, 2.5% with TSP and FSP deficiency and PAI raising in the 7.6%). CONCLUSIONS: In Septentrional Navarra population with thromboembolic disease the presence of hypercoagulable states is high. In our study, the most common hypercoagulable state was the presence of ACA, followed by PAI raising and by the CP deficiency.

Adult↗
PubMed1997

Risk factors for deep venous thrombosis of the upper extremities.

BACKGROUND: Hypercoagulable states and triggering factors (surgery, trauma, immobilization, pregnancy, and use of oral contraceptives) are associated with an increased risk for deep venous thrombosis of the lower extremities. In contrast, risk factors for deep venous thrombosis of the upper extremities have not been identified. OBJECTIVE: To evaluate the prevalence of hypercoagulable states and triggering factors in patients with primary deep venous thrombosis of the upper extremities. DESIGN: Frequency-matched case-control study. SETTING: Hemophilia and thrombosis center at a university hospital. PATIENTS: 36 patients who had primary deep venous thrombosis of the upper extremities, 121 patients who had primary deep venous thrombosis of the lower extremities, and 108 healthy controls. Patients who had deep venous thrombosis of the lower extremities and study controls were frequency-matched by age, sex, geographic origin, and social status with patients who had deep venous thrombosis of the upper extremities. MEASUREMENTS: Resistance to activated protein C was evaluated by a clotting method based on the activated partial thromboplastin time. If test results were abnormal or borderline, DNA analysis for substitution in coagulation factor V gene was done. Antithrombin, protein C, protein S, antiphospholipid antibodies, and total plasma homocysteine levels were also measured. RESULTS: Prevalences of abnormalities of the natural anticoagulant system (9%) and hyperhomocysteinemia (6%) in patients who had deep venous thrombosis of the upper extremities were similar to prevalences of both factors in controls (6% and 7%, respectively) but lower than in patients who had deep venous thrombosis of the lower extremities (31% and 14%, respectively). Antiphospholipid antibodies were found only in patients who had venous thrombosis of the lower extremities (7%). The overall prevalence of hypercoagulable states in patients who had thrombosis of the upper extremities (15%) was similar to that in controls (12%) but was significantly lower than that in patients who had thrombosis of the lower extremities (56%). A recent history of strenuous exercise of muscles in the affected extremity was the most frequent triggering factor for patients who had deep venous thrombosis in the upper extremities (33%). CONCLUSIONS: This preliminary study indicates that the prevalence of hypercoagulable states is low in patients who have primary deep venous thrombosis of the upper extremities.

Adult↗
PubMed1973

Interactions of the classical and alternate complement pathway with endotoxin lipopolysaccharide. Effect on platelets and blood coagulation.

The contributions of the classical and alternate pathways of complement activation to the biological effects of endotoxin have been examined in the guinea pig, with particular reference to thrombocytopenia, leukopenia, and the development of the hypercoagulable state. Injection of endotoxin into normal guinea pigs led to a 95% fall in the level of circulating platelets within 15 min as well as a fall in circulating granulocytes. C4-deficient guinea pigs, known to have a complete block in the activity of the classical complement pathway, but with the alternate pathway intact, sustained no fall in platelets. The development of granulocytopenia proceeded normally. Endotoxin did activate the alternate complement pathway in C4D guinea pigs, as evidenced by the fall in C3-9 titers. With restoration of serum C4 levels, endotoxin-induced thrombocytopenia was observed in C4D animals. Thus, function of the classical complement pathway was an absolute requirement for the development of thrombocytopenia. Experiments performed in cobra venom factor (CVF)-treated normal guinea pigs, with normal levels of C1, C4, and C2, but with less than 1% of serum C3-9 demonstrated the importance of the late components in the development of thrombocytopenia but not leukopenia.C4-deficient guinea pigs had normal clotting times demonstrating that C4 was not required for normal clotting. In addition, development of the hypercoagulable state, evidenced by a marked shortening of the clotting time, was not observed on injection of endotoxin into C4D animals. Therefore, development of the hypercoagulable state paralleled the development of thrombocytopenia and required function of the classical complement pathway. Again, the importance of the late components of complement was emphasized by the failure of CVF-treated normal animals to develop hypercoagulability. These results demonstrate that endotoxin is capable of activating both the classical and alternate complement pathways in guinea pigs but that function of the classical pathway is an absolute requirement for the development of thrombocytopenia and the hypercoagulable state.

Animals↗
PubMed2006

Thrombophilias and recurrent pregnancy loss.

Thrombophilia by definition represents acquired and/or genetic conditions that predispose patients to both venous and arterial thromboembolic events. Thrombosis is the most common cause of death worldwide. On the arterial side, myocardial infarction and stroke result in significant morbidity and mortality. Venous thromboembolic events most commonly involve the deep veins of the lower extremity with potential complications of pulmonary emboli. Pregnancy is a hypercoagulable state, and thromboembolism is the leading cause of antepartum and postpartum maternal mortality. With the description by Dahlback in 1993 of a condition initially labeled activated protein C resistance, significant advances have rapidly followed. Activated protein C resistance was linked to an underlying point mutation resulting in coagulation factor V (factor V Leiden). Recent attention has focused on certain inherited thrombophilic factors that may predispose to arterial and/or venous thromboses and their possible association with pregnancy complications, including early pregnancy loss. These include a group of mostly autosomal dominant, inherited gene mutations leading to a hypercoagulable state, such as factor V Leiden G1691A, factor II or prothrombin G20210A, and hyperhomocysteinemia associated with methylenetetrahydrofolate reductase C677T mutation. In addition, deficiencies in protein S, protein C, and antithrombin can lead to a hypercoagulable state. Although some studies of recurrent pregnancy loss patients with a positive test for an inherited thrombophilia are conflicting, a case-control study of untreated recurrent miscarriage patients who were heterozygous for the factor V Leiden mutation revealed a lower success rate than the controls who had a history of idiopathic recurrent miscarriage. With the identification of genetic risk factors, there has been synergistic amplification of thrombotic risk when one has an abnormal gene (e.g., factor V Leiden) plus environmental issues (e.g., pregnancy). Current understanding indicates that a combination of risk factors, including multiple inherited thrombophilic defects associated with secondary hypercoagulable states, have a particularly strong association with adverse pregnancy outcome.

Abortion, Habitual↗
PubMed1996

Use of enzyme-linked immunosorbent assay to measure thrombin-antithrombin III complexes in horses with colic.

OBJECTIVES: To evaluate new ELISA for measurement of thrombin-antithrombin III (TAT) concentration, and to correlate the values to other tests of hemostasis in horses with colic. DESIGN: Plasma TAT concentration and 8 other hemostasis analytes were measured in horses with colic at hospital admission and during the next 4 days. Retrospectively, data were analyzed by outcome, broad-category diagnosis, and clinical management, and for correlation between TAT and other assays. ANIMALS: 100 horses with colic. PROCEDURE: Plasma samples were evaluated for TAT, fibrinogen, and fibrin degradation products concentrations; antithrombin III (ATIII), protein C, alpha 2-antiplasmin, and plasminogen activities; prothrombin time (PT); and activated partial thromboplastin time. RESULTS: Changes were indicative of a hypercoagulable state, most severe in nonsurviving horses, characterized by increased TAT concentration; decreased ATIII, protein C, and plasminogen activities; and increased PT. Nonsurvivors had significantly increased TAT concentration compared with that in survivors, without regard to sample collection time; however, compared over time, TAT was significantly increased only at admission. Highest TAT concentration was in nonsurvivors with inflammatory intestinal lesions. There was significant negative correlation between TAT and ATIII, protein C, alpha 2-antiplasmin, and plasminogen values, and significant positive correlation between TAT and PT, and fibrin degradation products values. CONCLUSIONS: Plasma TAT reflects the current state of coagulation system activation and is a good assay for early diagnosis of the hypercoagulable state in horses with the most severe forms of colic. CLINICAL RELEVANCE: Measurement of equine TAT provides further information to characterize the hypercoagulable state in horses to aid in case management.

Analysis of Variance↗
PubMed1990

Treatment of patients with disseminated intravascular coagulation by protein C.

The therapeutic effect of highly purified protein C (PC) or activated protein C (APC) on three patients with disseminated intravascular coagulation (DIC) was tested. In two out of three cases, although therapeutic dose of heparin was not effective, PC or APC administration significantly improved the hypercoagulable state. In one case with acute leukemia who developed DIC with the severe gastrointestinal bleeding, APC corrected the hypercoagulable state without aggravating bleeding. These findings suggested that PC and/or APC might be effective in correcting hypercoagulable state without any adverse effect.

Anticoagulants↗
PubMed1991

Appearance of thrombosis-inducing activity in the plasma of patients undergoing pulmonary resection.

Thrombosis-inducing activity (TIA) was detected in the peripheral blood of patients with lung cancer who had undergone pulmonary resection. TIA was examined by intravenously injecting plasma from the patients into BALB/c mice. The plasma containing TIA induced multiple thromboses in the lung and caused the mice to die 3 to 30 minutes after injection. The subjects were 19 patients whose plasma contained no TIA before operation. TIA was detected in 5.3 percent (1/19) on the first postoperative day (POD), 47.4 percent (9/19) on the seventh POD, 47.1 percent (8/17) on the 14th POD, 26.7 percent (4/15) on the 21st POD, and 20 percent (2/10) on the 28th POD. Plasma fibrinogen levels and peripheral platelet counts increased postoperatively and reached a maximum on the seventh and 14th POD, respectively. Peripheral blood with TIA had a significant elevation of plasma fibrinogen levels and platelet counts as compared to that without TIA. These observations suggest that TIA is present in blood in a hypercoagulable state in patients after pulmonary resection. Since tumor necrosis factor and interleukin 1 are known to induce hypercoagulable states both in vitro and in vivo, we tried to determine whether it was possible to detect both cytokines in blood indicated as hypercoagulable state by the presence of TIA. They did not, however, reach detectable levels in the blood.

Aged↗
PubMed2002

Anticoagulant prophylaxis markedly reduces thromboembolic complications in Cushing's syndrome.

A hypercoagulable state and an increased incidence of thromboembolic complications are reported in Cushing's syndrome. The hypercoagulable state is related to an increase in plasma clotting factors, especially Factor VIII and von Willebrand factor complex, and to an impairment of fibrinolytic capacity. Retrospective analysis of postoperative thromboembolic events in a large group of patients with Cushing's syndrome, including 75 patients (group 1) evaluated in the period from 1972-1981 not receiving anticoagulants, and 232 patients (group 2), evaluated in the period from 1982-2000. Patients of group 1 underwent routine hemostatic function, i.e. prothrombin time and activated partial thromboplastine time. Patients of group 2 underwent a thorough investigation as to hemostatic parameters and received prophylactic treatment with heparin and/or warfarin. Patients with Cushing's syndrome showed various abnormalities of hemostatic parameters. A significant correlation between activated partial thromboplastine time and urinary free cortisol was observed. During follow-up, 15 patients (20%; mean follow-up, 9.4 +/- 6.4 yr) of group 1 and 14 (6.0%; mean follow-up, 6.6 +/- 4.2 yr) of group 2 showed thromboembolic complications. Of these patients, eight of group 1 and one of group 2 died. Survival analysis demonstrated a significantly higher morbidity and mortality due to thromboembolic events in group 1, not receiving anticoagulant prevention, than in group 2, treated with anticoagulants in the perioperative period until cure of the disease and normalization of clotting parameters. Cushing's syndrome is associated with a hypercoagulable state. An adequate anticoagulant prophylaxis can reverse this prothrombotic state and avoid postoperative thromboembolic events.

Adolescent↗
PubMed1995

Acute aortic occlusion--factors that influence outcome.

PURPOSE: The purpose of this study was to report our experience in the management of acute aortic occlusion and to analyze factors that influenced the outcome. METHODS: This was a retrospective analysis of 48 patients with acute aortic occlusion treated over a 19-year period. Presentation included limb ischemia in 34, acute abdomen in four, spinal cord compression-like symptoms in eight, and sudden onset of hypertension in two patients. Thrombosis was the cause of acute aortic occlusion in 44, and embolus in four patients. Acute thrombosis was associated with underlying atherosclerotic occlusive disease in 36 patients. In these, thrombosis was due to low-flow state caused by cardiac dysfunction or severe volume depletion. Thrombosed aneurysms caused aortic occlusion in two patients. Hypercoagulable state caused thrombosis of relatively normal aorta in six patients. Angiography in 39 patients revealed occlusion to be juxtarenal or infrarenal in 37 and suprarenal in two. Left ventricular function (LVF) was assessed in 42 patients. Circulation was restored in 45 (aortofemoral bypass in 22, axillofemoral bypass in 12, and thromboembolectomy in 11). This was not feasible in three patients. Additional surgical procedures were required in 29 patients (64%). RESULTS: The overall mortality rate was 52% (25 of 48). Of the 20 patients with severely compromised LVF, 17 died (85%). In contrast, only five (23%) deaths occurred among 22 with good LVF. Among 29 patients who required additional operations, 18 died (62%). All four patients with embolic occlusion survived. Patients with normal LVF but hypercoagulable state had dismal outcome--only one of the six survived. CONCLUSIONS: Acute aortic occlusion is infrequent. Presentation may be varied, thus delaying diagnosis. Poor LVF, thrombosis of arteries below the inguinal ligament or of visceral arteries, and "hypercoagulable state" portend ominous prognosis.

Acute Disease↗
PubMed2001

Hypercoagulable syndromes: evaluation and management strategies for acute limb ischemia.

Acute limb ischemia secondary to peripheral arterial thrombosis is a relatively uncommon but ominous form of vascular accident. Select inherited and acquired hypercoagulable states appear to contribute to an initial arterial thrombosis and, more importantly, recurrent thrombotic events. Mounting interest in hypercoagulability, the increased availability of hypercoagulable state "profiles," and enhanced ability to identify an abnormality in tested patients have promoted widespread testing. Unfortunately, widespread testing has had a limited beneficial impact on the management of acute limb ischemia. Ideally, costly and specialized testing should be limited to situations in which the results will have a tangible impact on patient care. Clear goals of testing should be determined before testing is performed. This article addresses a practical approach to hypercoagulable state testing in patients with acute limb ischemia with a focus on abnormalities that impact patient management.

Acute Disease↗
PubMed2005

Hextend attenuates hypercoagulability after severe liver injury in swine.

BACKGROUND: Hypercoagulability is a major source of morbidity and mortality after injury. A resuscitation regimen that modulates this coagulopathy may prove beneficial. We sought to evaluate the effects of lactated Ringer's (LR) solution and Hextend on the resuscitation of uncontrolled hemorrhagic shock. METHODS: Twenty swine underwent invasive line placement, midline celiotomy, and splenectomy. After a 15-minute stabilization period, we recorded a baseline mean arterial pressure and created a grade V liver injury. The animals bled freely for 30 minutes, after which we measured the initial blood loss (that after injury). We blindly randomized the swine to receive LR solution or Hextend to achieve and maintain the baseline mean arterial pressure for 90 minutes postinjury. Laboratory values were obtained at baseline and on completion of the 2-hour study period. RESULTS: The initial blood loss (before resuscitation) was 22 mL/kg in both treatment groups (p = 0.97). Animals required 119 +/- 78 mL/kg of fluid in the LR group and 40 +/- 21 mL/kg in the Hextend group (p = 0.01). After resuscitation, the secondary blood loss was 3.7 +/- 1.7 mL/kg in the LR group and 4.7 +/- 1.1 mL/kg in the Hextend group (p = 0.1). Thrombelastography revealed a hypercoagulable state in all animals after injury. This was less pronounced in those animals resuscitated with Hextend. Routine tests of coagulation did not reveal a hypercoagulable state. CONCLUSION: Modulation and restoration of normal coagulation is critical in the management of trauma patients. The patient's coagulation profile might determine the type of fluid to be used at various times during their course. Thrombelastography is superior to routine coagulation assays for the detection of a hypercoagulable state. Resuscitation with Hextend results in a decreased fluid requirement and attenuation of hypercoagulability after injury without increased blood loss.

Animals↗
PubMed2000

[Blood coagulation changes and neoplastic pathology].

Cancer patients show an increased susceptibility to develop thromboembolic diseases, suggesting that disorders of coagulation are very common in this pathology. Tumor cells possess the capacity to interact with the hemostatic system, activating the coagulation cascade and stimulating the prothrombotic properties of other blood cell components; the same events while inducing a hypercoagulable state, also contribute to the processes of tumor growth, neoangiogenesis and metastatic formation. Multiple risk factors associated with malignant disease contribute to the hypercoagulability state: stasis induced by prolonged bed rest, vascular invasion by the tumor and iatrogenic complications including the use of central vein catheters and chemotherapy. Several tests have been developed to assess the hypercoagulable state, however their clinical significance still needs to be defined, especially in terms of their predictive value for thrombosis. Clinical manifestations vary from localized deep venous thrombosis (DVT) or pulmonary embolism, more generally associated with solid tumors, to disseminated intravascular coagulation, frequent in hematologic malignancies and metastatic cancer. Diagnosis of idiopathic DVT, in the absence of other risk factors, could indicate the presence of occult cancer, but the usefulness of an extensive work-up to detect malignancy in terms of cost to benefit ratio still has to be demonstrated. Patients with cancer and thromboembolism must be treated with anticoagulant therapy; a large number of studies have shown that either low molecular weight heparins or standard unfractionated heparin for the treatment of acute deep vein thrombosis in hospitalized patients are equally safe and effective; however, the first treatment has been reported to be associated with a lower mortality. After an episode of thrombosis the patients should be protected by a long term course of oral anticoagulation, remaining high the risk of recurrence for as long as the cancer is active.

Blood Coagulation↗
PubMed1999

Coagulation abnormalities and their neuro-ophthalmologic manifestations.

Congenital and acquired hypercoagulable states arise from an imbalance between procoagulant and anticoagulant forces. Although these conditions are present throughout the vascular tree, they typically give rise to local thrombotic lesions in discrete segments of the veins or arteries; this suggests that focal defects in the vascular wall or blood flow must be associated with a hypercoagulable state to produce thrombosis. Numerous new factors associated with hypercoagulability have been described in the past few years. Congenital and acquired hypercoagulable states are reviewed here, with an emphasis on recent data on focal thrombosis involving the eye and central nervous system.

Blood Coagulation Factors↗
PubMed2002

[Study on stroke syndrome of Chinese medicine and its relationship with blood hypercoagulative status and insulin resistance in diabetic ischemic stroke patients].

OBJECTIVE: To study the relationship of TCM Syndromes, involving Viscera Syndrome and involving Meridian Syndrome, with blood hypercoagulative state and insulin resistance in patients with diabetic ischemic stroke. METHODS: Insulin sensitivity index (ISI) could reflect the insulin resistance, and those reflecting blood hypercoagulative state parameters such as platelet agglutination test (PAgT), fibrinogen (FG), in vitro thrombus length (VTL) and activating partial thrombinogen time (APTT), were used to expound and prove the relationship with the stroke syndrome. RESULTS: The symptom scores, PAgT, VTL, FG levels in patients involved with Viscera Syndromes (including those of Wind Syndrome, Phlegm-Dampness Syndrome, Heat-Fire Syndrome and Yin-deficiency with Yang-excess Syndrome) were significantly higher than those in patients involved with Meridian Syndromes (P < 0.05 or P < 0.01), while the ISI level in the former was lower than that in the latter (P < 0.01). CONCLUSION: There is close relationship between blood hypercoagulative state, insulin resistance and TCM Stroke Syndromes in patients with diabetic ischemic stroke.

Aged↗
PubMed2000

Prothrombotic factors in nephrotic syndrome.

Nephrotic syndrome is a hypercoagulable state with variable prevalence of clinical thrombosis. The role of platelet aggregation, fibrinogen and antithrombin III and protein S levels in the pathogenesis of hypercoagulable state in these patients is controversial. Since no study on Indians is available, the clinical and laboratory profile of 22 patients of nephrotic syndrome (age 18-35 years with an MF ratio of 4:3), have been studied. The coagulation profile revealed a prolonged APTT in 12 patients (54.5%), and a prolonged TT in four (18.1%). In the rest APTT and TT were normal. PT was raised in two patients. Fibrinogen, an acute phase reactant was raised in five patients (22.7%). Antithrombin III levels were reduced in 19 patients (86.4%), normal in one and raised in two patients. Free Protein S levels were high in 12(54.5%), normal in seven and decreased in three patients. Platelet aggregation with adrenaline and adenosine diphosphate was raised in 6 patients. Ultrasonographically detected deep vein thrombosis was seen in one patient only (4.5%) who had ATIII levels of 48%. This low incidence can be explained by elevated protein S levels which was found to be raised in 12(54.5%) cases, protein S being an anticoagulant factor. This low level of clinical thrombosis in Indian patients of nephrotic syndrome may be an ethnic variable factor. It is thus concluded that although patients with nephrotic syndrome have a hypercoagulable state, clinical thrombosis is rarely seen in Indian patients with nephrotic syndrome.

Adolescent↗
PubMed1985

A primate model (Macaca mulatta) to study the pharmacokinetics of heparin and its fractions.

We have extensively studied the hemostatic parameters and the responses to the anticoagulant action of heparin and its fractions in the primate model (M. mulatta) and found these to be identical to those obtained in humans. The functional properties of antithrombin III, alpha 2-antiplasmin, and platelet factor 4 were also identical to humans in amidolytic and coagulant assays. Human antibodies against FPA, B beta 15-42 peptide, platelet factor 4, and thromboxane B2 reacted with the primate antigen, and assays were developed to measure these parameters in primates. Infusion of activated prothrombin complex concentrates (more than 100 U/kg/day) on a continual basis up to 3 days resulted in a hypercoagulable state manifested by an elevation of FPA, thromboxane B2, and changes in the thrombelastographic patterns. Similarly, infusion of homologous primate serum also resulted in a hypercoagulable state, as was evident by a sharp increase in the FPA levels. The antithrombotic effects of intravenous and subcutaneous administration of heparin, its low molecular fraction, and their constituents were studied after intravenous and subcutaneous injections. The low molecular weight fractions showed the most effective antithrombotic effects, whereas somewhat milder protection was observed with the starting material and highly anionic fraction. The prolongation of global tests, such as the APTT, TT, and changes in the thromboelastogram did not correlate with the reduction in the blood markers of hypercoagulable state. A modified simplate bleeding time method was used to study the effect of heparin and its fractions on the bleeding profile of heparin fractions. The components of fibrinolytic systems were also measurable in both the clot-based and amidolytic methods to predict the profibrinolytic actions of heparin fractions in its mode. These studies suggest that plasma markers, such as the platelet release proteins, products of thrombin activation, and prostaglandin metabolites, may provide better indices in the monitoring of the antithrombotic actions of newer heparins and antithrombotic drugs. Studies suggest that the pathophysiologic responses after a thrombogenic trigger in the primate model are close to humans, and drug modulation of these may provide relevant clinical information. This model provides the most similar preclinical model to study the actions of heparin fractions.

Animals↗
PubMed2001

Resuscitation with Hextend decreases endogenous circulating heparin activity and accelerates clot initiation after hemorrhage in the rabbit.

UNLABELLED: Hemorrhagic shock can result in a hypercoagulable state and has been associated with both hemorrhagic and thrombotic complications in the perioperative period. The author hypothesized that hemorrhage and resuscitation could result in a hypercoagulable state via changes in the heparin-antithrombin III anticoagulant mechanism in rabbits. Rabbits sedated with ketamine underwent sham operation (n = 8) or hemorrhage (25 mL/kg blood shed) for 60 min, followed by resuscitation with an equal volume of 5% human albumin (n = 8) or Hextend (n = 8). Coagulation analysis with the Thrombelastograph analyzer and determination of endogenous heparin and antithrombin III activity were performed on arterial blood samples obtained before hemorrhage and 30 min after resuscitation. The reaction time significantly decreased by 34% after hemorrhage and resuscitation with Hextend, whereas no other significant changes in Thrombelastograph variables were noted. Antithrombin III activity was significantly less in the Albumin (83% +/- 8% of control, mean +/- SD) and Hextend (88% +/- 8%) Resuscitated groups compared with the Sham-Operated animals. Of interest, only the Hextend-Resuscitated animals demonstrated a significant decrease in heparin activity (53.4 +/- 13.6 mU/mL before hemorrhage, 42.3 +/- 5.6 mU/mL after resuscitation). A Hextend)-mediated decrease of both heparin and antithrombin III activity may explain the acceleration of clot initiation compared with albumin administration after hemorrhage in the rabbit. IMPLICATIONS: Hemorrhage may result in a hypercoagulable state after resuscitation. Decreases in both endogenous heparin and antithrombin III activity after hemorrhage and Hextend resuscitation in rabbits resulted in a significantly decreased time to clot coagulation analysis initiation without a significant change in the rate of clot formation or final clot strength.

Animals↗