kaolinite and Thrombocytopenia

Anticoagulation with recombinant hirudin (r-hirudin) (Refludan) has been suggested as an alternative to heparin for patients with heparin-induced thrombocytopenia requiring cardiac surgery. We sought to develop a modified activated coagulation time (ACT) that would allow quantification of the levels of r-hirudin required during cardiopulmonary bypass (CPB). Twenty-one patients scheduled for elective cardiac surgical procedures requiring CPB were enrolled in this IRB-approved study. R-hirudin was added to blood specimens obtained before heparin administration (before CPB) and 30 min after heparin neutralization with protamine (after CPB) to result in concentrations of 0, 2, 4, 6, 7, or 8 microg/mL. Kaolin/ACT and complete blood count measurements were assayed in native specimens (first 10 patients, Phase I) or in specimens mixed with equal volumes of commercial normal plasma (second 11 patients, Phase II). In Phase I, good (r(2) = 0.83) linear relationships between ACT values and r-hirudin concentrations (< or =4 microg/mL) were observed in specimens obtained before CPB. However, ACT values were markedly prolonged (P < 0.0001) by r-hirudin in specimens obtained after CPB, with ACT values generally exceeding the ACT's detection limit (>999 s) at hirudin concentrations >2 microg/mL. In patient specimens mixed with normal plasma (Phase II), ACT/hirudin relationships (i.e., hirudin/ACT slope values obtained with hirudin concentration < or =4 microg/mL) in the post-CPB period (0.022 +/- 0.004 microg. mL(-1). s(-1)) were similar (P = 0.47) to those (0.019 +/- 0.004 microg. mL(-1). s(-1)) obtained in the pre-CPB period. Accordingly, a significant relationship between normal plasma-supplemented ACT values and predilution hirudin concentration was obtained in the post-CPB (hirudin = 0.039ACT - 4.34, r(2) = 0.91) period. Although our data demonstrate that the ACT test cannot be used to monitor hirudin during CPB, the addition of 50% normal plasma to post-CPB hemodiluted blood specimens yields a consistent linear relationship between hirudin concentration and ACT values up to a predilution concentration of 8 microg/mL. Plasma-modified ACT may be useful in monitoring hirudin anticoagulation during CPB.. A modified activated clotting time test system that may be helpful in monitoring hirudin anticoagulation in patients with heparin-induced thrombocytopenia during cardiac surgery with cardiopulmonary bypass is described.

Topics: Anticoagulants; Antithrombins; Cardiopulmonary Bypass; Hematocrit; Heparin; Hirudins; Humans; Kaolin; Platelet Count; Thrombocytopenia; Whole Blood Coagulation Time

To determine whether thromboelastography is more accurate than conventional methods of evaluating hemostasis for the prediction of clinical bleeding in thrombocytopenic dogs following total body irradiation (TBI) and bone marrow transplantation (BMT).. 10 client-owned thrombocytopenic dogs with multicentric lymphoma.. Results of a kaolin-activated thromboelastography assay, platelet count, and buccal mucosal bleeding time were evaluated for correlation to clinical bleeding.. Maximum amplitude, derived via thromboelastography, was the only hemostatic variable with significant correlation to clinical bleeding. Buccal mucosal bleeding time had a high sensitivity but poor specificity for identifying dogs with clinical bleeding.. Compared with buccal mucosal bleeding time and platelet count, thromboelastography was more reliable at identifying thrombocytopenic dogs with a low risk of bleeding and could be considered to help guide the use of transfusion products in dogs undergoing TBI and BMT.

Topics: Animals; Bone Marrow Transplantation; Cohort Studies; Dog Diseases; Dogs; Hemorrhage; Hemostasis; Kaolin; Lymphoma; Male; Platelet Count; Prospective Studies; Thrombelastography; Thrombocytopenia; Whole-Body Irradiation

Thromboelastography/metry (TEG®; Haemoscope, Niles, IL/ROTEM®; Tem International GmbH, Munich, Germany) is increasingly used to guide transfusion therapy. This study investigated the diagnostic performance and therapeutic consequence of using kaolin-activated whole blood compared with a panel of specific TEM®-reagents to distinguish: dilutional coagulopathy, thrombocytopenia, hyperfibrinolysis, and heparinization.. Blood was drawn from 11 healthy volunteers. Dilutional coagulopathy was generated by 50% dilution with hydroxyethyl starch 130/0.4 whereas thrombocytopenia (mean platelet count 20 ×10⁹/l) was induced using a validated model. Hyperfibrinolysis and heparin contamination were generated by tissue plasminogen activator 2 nM and unfractionated heparin 0.1U/ml, respectively. Coagulation tests were run on ROTEM® delta.. Kaolin-activated whole blood showed no differences between dilutional coagulopathy and thrombocytopenia (mean clotting time 450 s vs. 516 s, α-angle 47.1° vs. 41.5°, maximum clot firmness 35.0 mm vs. 34.2 mm, all P values ≥0.14). Hyperfibrinolysis specifically disclosed an increased maximum lysis (median: 100%, all P values less than 0.001), and heparin induced a distinctly prolonged clotting time (2283 s, all P values less than 0.02). The coagulopathies were readily distinguishable using a panel of TEM-reagents. In particular, dilutional coagulopathy was separated from thrombocytopenia using FIBTEM (maximum clot firmness 1.9 mm vs. 11.2 mm, P < 0.001). The run time of analysis to achieve diagnostic data was shorter applying a panel of TEM-reagents. A transfusion algorithm based on kaolin suggested platelets in case of dilutional coagulopathy, whereas an algorithm applying TEM-reagents suggested fibrinogen.. Monoanalysis with kaolin was unable to distinguish coagulopathies caused by dilution from that of thrombocytopenia. Algorithms based on the use of kaolin may lead to unnecessary transfusion with platelets, whereas the application of TEM-reagents may result in goal-directed fibrinogen substitution.

Topics: Adult; Algorithms; Blood Coagulation Disorders; Female; Fibrinolysis; Hemostasis; Humans; Indicators and Reagents; Kaolin; Male; Middle Aged; Thrombelastography; Thrombocytopenia; Time Factors

Antiphospholipid (aPL) antibodies include anticardiolipin (aCL) and lupus anticoagulant (LA) antibodies. LA antibodies recognize the complex of lipid-bound (human) prothrombin, in this way inhibiting the phospholipid-dependent coagulation reactions, whereas aCL antibodies are directed towards beta 2-glycoprotein I (beta 2-GPI) bound to an anionic lipid surface. According to their behavior in coagulation reactions, we have divided aCL antibodies into two groups: aCL-type A, which inhibit the phospholipid-dependent coagulation reactions because they enhance the binding of beta 2-GPI to the procoagulant phospholipid surface; and aCL-type B antibodies, which are devoid of anticoagulant properties. We report the distinctive laboratory and clinical profiles of 25 patients with well-characterized, phospholipid-dependent inhibitor of coagulation. Fourteen patients had LA antibodies (aCL-type B were concomitantly present in 10 cases, while in the other four, aCL titer was normal), and the other 11 had aCL-type A antibodies. The laboratory evaluation of the two groups showed the dilute Russell viper venom time (dRVVT) to be the most abnormal coagulation test in the aCL-type A-positive group, whereas the kaolin clotting time (KCT) was the most abnormal assay in the LA-positive group. In fact, the ratios of the coagulation times of patient plasma over normal pooled plasma (mean +/- standard deviation) for LA versus aCL-type A antibodies were 1.48 +/- 0.27 versus 2.20 +/- 0.42, P = .0001, and 2.22 +/- 0.42 versus 1.50 +/- 0.42, P = .0003, for the dRVVT and KCT, respectively. No differences were observed either in the ratios of the activated partial thromboplastin times and the prothrombin times or the plasma levels of beta 2-GPI and prothrombin. Conversely, aCL titers were significantly higher in aCL-type A-positive patients (147 +/- 44 U) than in the LA-positive group (61 +/- 55 U; P = .0003). We ruled out the possibility that platelet contamination of plasma could account for the observed coagulation profiles, as the two patterns were reproduced in platelet-free plasma. In addition, we performed clotting tests in plasma in the presence of phospholipids and calcium after addition of factor IXa or factor Xa. The assay performed with factor Xa was more sensitive to the presence of aCL-type A antibodies, while the assay performed with factor IXa was preferentially sensitive to LA-containing plasmas, supporting the earlier findings with the dRVVT and KCT assays.(ABSTRACT

Topics: Adolescent; Adult; Aged; Anemia, Hemolytic, Autoimmune; Antibodies, Anticardiolipin; Antibodies, Antiphospholipid; Antiphospholipid Syndrome; Autoantigens; beta 2-Glycoprotein I; Blood Coagulation; Blood Coagulation Tests; Disease Susceptibility; Female; Glycoproteins; Humans; Immunoglobulin G; Immunoglobulin M; Kaolin; Lupus Coagulation Inhibitor; Lymphoma, Non-Hodgkin; Macromolecular Substances; Male; Middle Aged; Phospholipids; Protein Binding; Prothrombin; Prothrombin Time; Risk Factors; Thrombocytopenia; Thromboembolism

Twelve Indian patients with pre-eclampsia, 15 with eclampsia and 15 with normal pregnancy in the third trimester were investigated. A systemic bleeding diathesis was encountered in two patients with eclampsia and in none with pre-eclampsia; two patients with pre-eclampsia, however, had excessive uterine haemorrhage. Coagulation studies showed statistically significant prolongation of thrombin time, elevation of serum fibrinogen degradation products (FDP) and hypofibrinogenaemia in patients with pre-eclampsia as well as eclampsia. In patients with eclampsia, significant thrombocytopenia also occurred. Euglobulin lysis time showed no significant change in patients with pre-eclampsia and eclampsia. There was no significant difference in the coagulation profile between patients with eclampsia and pre-eclampsia, except for more hypofibrinogenaemia in the former. The laboratory findings suggest the occurrence of intravascular coagulation in patients with pre-eclampsia and eclampsia.

Topics: Adult; Albuminuria; Blood Coagulation; Blood Coagulation Disorders; Blood Platelets; Eclampsia; Edema; Female; Fibrinogen; Hemorrhagic Disorders; Humans; Hypertension; India; Kaolin; Middle Aged; Phosphatidylethanolamines; Pre-Eclampsia; Pregnancy; Pregnancy Trimester, Third; Prothrombin Time; Serum Globulins; Thrombocytopenia; Uterine Hemorrhage

Topics: Adenine Nucleotides; Blood Platelet Disorders; Blood Platelets; Bone Marrow Cells; Collagen; Electrophoresis; Freezing; Hemostasis; Humans; In Vitro Techniques; Kaolin; Macrophages; Megakaryocytes; Microscopy, Electron; Mononuclear Phagocyte System; Phagocytosis; Platelet Adhesiveness; Thrombocytopenia; Wiskott-Aldrich Syndrome

Topics: Adolescent; Adult; Blood Coagulation Disorders; Blood Coagulation Factors; Child; Child, Preschool; Factor VII; Factor VIII; Factor XIII; Female; Humans; Infant; Kaolin; Lymphoma, Non-Hodgkin; Male; Prothrombin Time; Pulmonary Embolism; Thrombocytopenia; Thrombophlebitis; Thromboplastin; Wiskott-Aldrich Syndrome