Antiplatelet Medications and Biomarkers of Hemostasis May Explain the Association of Hematoma Appearance and Subsequent Hematoma Expansion After Intracerebral Hemorrhage

BACKGROUND

To test the hypothesis that appearances of intracranial hematomas on diagnostic computed tomography (CT) are not idiosyncratic and reflect a biologically plausible mechanism, we evaluated the association between hematoma appearance on CT, biomarkers of platelet activity, and antiplatelet or anticoagulant medication use prior to admission.

METHODS

We studied 330 consecutively identified patients from 2006 to 2019. Biomarkers of platelet activity (platelet aspirin assay) and medication history (aspirin, clopidogrel) were prospectively recorded on admission. A blinded interpreter recorded the presence of hematoma appearances from the diagnostic scan. Associations were tested with parametric or nonparametric statistics, as appropriate.

RESULTS

The black hole sign (101, 30%) was most prevalent, followed by the island sign (57, 17%) and blend sign (32, 10%). There was reduced platelet activity in patients with a black hole sign (511 [430-610] vs. 562 [472-628] aspirin reaction units, P = 0.01) or island sign (505 [434-574] vs. 559 [462-629] aspirin reaction units, P = 0.004). Clopidogrel use prior to admission was associated with the black hole sign (odds ratio 2.25, 95% confidence interval 1.02-4.98, P = 0.04).

CONCLUSIONS

In patients with acute intracerebral hemorrhage, hematoma appearances on CT are associated with biomarkers of platelet activity and clopidogrel use prior to admission. Appearances of intracranial hematomas on CT may reflect reduced hemostasis from antiplatelet medication use.

Viscoelastic testing in oncology patients (including for the diagnosis of fibrinolysis): Review of existing evidence, technology comparison, and clinical utility

The quantification of the coagulopathic state associated with oncologic and hematologic diseases is imperfectly assessed by common coagulation tests such as prothrombin time, activated partial thromboplastin time, fibrinogen levels, and platelet count. These tests provide a static representation of a component of hemostatic integrity, presenting an incomplete picture of coagulation in these patients. Viscoelastic tests (VETs), such as rotational thromboelastometry (ROTEM) and thromboelastography (TEG), as whole blood analyses, provide data related to the cumulative effects of blood components and all stages of the coagulation and fibrinolytic processes. The utility of VETs has been demonstrated since the late 1960s in guiding blood component therapy for patients undergoing liver transplantation. Since then, the scope of viscoelastic testing has expanded to become routinely used for cardiac surgery, obstetrics, and trauma. In the past decade, VETs' expanded usage has been most significant in trauma resuscitation. However, use of VETs for patients with malignancy-associated coagulopathy (MAC) and hematologic malignancies is increasing. For the purposes of this narrative review, we discuss the similarities between trauma-induced coagulopathy (TIC) and MAC. These similarities center on the thrombomodulin-thrombin complex as it switches between the thrombin-activatable fibrinolysis inhibitor coagulation pathway and activating the protein C anticoagulation pathway. This produces a spectrum of coagulopathy and fibrinolytic alterations ranging from shutdown to hyperfibrinolysis that are common to TIC, MAC, and hematologic malignancies. There is expanding literature regarding the utility of TEG and ROTEM to describe the hemostatic integrity of patients with oncologic and hematologic conditions, which we review here.

Viscoelastic testing in benign hematologic disorders: Clinical perspectives and future implications of point-of-care testing to assess hemostatic competence

Viscoelastic tests (VETs) have been used routinely for liver transplantation, cardiac surgery, and trauma, but only recently have found clinical utility in benign hematologic disorders. Therefore, guidelines for diagnosis and treatment of these disorders based on viscoelastic variables have been adapted from the existing transplant, cardiothoracic surgery, and trauma resuscitation literature. As a result, diagnostic and therapeutic strategies for benign hematologic disorders utilizing VETs are not uniform. Accordingly, even though there has been a recent increase in the utilization of VET for the diagnosis and treatment of such disorders, the literature is still in its early stages. Analysis of point-of-care viscoelastic tracings from benign hematologic disorders has the potential to allow prompt recognition of disease and to guide patient-specific intervention. Here we present a review describing the application of VETs to benign hematologic disorders.

Complications of Implanted Nonbiologic Devices—An Overview

Under physiologic conditions, blood is contained within the vascular space lined with smooth endothelial cells. When various devices made of nonbiologic material are implanted, blood will be exposed to a foreign surface. A series of events ensue and may lead to many complications, including thrombosis, hemolysis, thrombocytopenia, bleeding, infection, and malfunction of the device. The incidence, manifestations, and special characteristics of these complications vary with different types of implanted devices. However, they have in common an important pathogenic pathway that of an exposure to a foreign surface. Despite the development of improved versions of these devices, more research on the causative factors of these complications is needed to take preventive and corrective measures, particularly those that enhance the process of healing by re-endothelialization of the foreign surface. This article is a brief review of the complications encountered in blood-contacting devices.

Delayed anithyroid drug-induced agranulocytosis

OBJECTIVE

To demonstrate that drug-induced agranulocytosis can occur after a very prolonged period of low-dose treatment with antithyroid medications.

METHODS

We present the history and long-term follow-up of a patient with Graves disease, including clinical and laboratory findings, and provide a brief review of the related literature.

RESULTS

A 53-year-old woman with a history of Graves disease presented with an absolute neutrophil count of zero, body temperature of 38.7°C, and symptoms of an upper respiratory tract infection. She had been treated continuously with low doses of antithyroid drugs for the preceding 11 years-propylthiouracil (100 to 150 mg daily) from February 1998 until July 2003 and methimazole (5 to 30 mg daily) from July 2003 until her presentation with severe neutropenia in March 2009. The daily dose of methimazole had been stable at 15 mg for 1 year before the current presentation. A thorough hematologic evaluation, including bone marrow biopsy, did not reveal an alternative cause for the agranulocytosis. After discontinuation of methimazole treatment and a short course of granulocyte colony-stimulating factor, she responded successfully with clinical improvement of her symptoms and resolved neutropenia.

CONCLUSION

Although this case is atypical, it reinforces the importance of remaining vigilant for signs of agranulocytosis throughout the course of treatment with antithyroid drugs, even at low doses and after years of continuous administration.

The impact of medical education and networking on the outcome of leukemia treatment in developing countries. The experience of International Consortium on Acute Promyelocytic Leukemia (IC-APL)

OBJECTIVES

Several clinical trials conducted in Europe and US reported favorable outcomes of patients with APL treated with the combination of all trans retinoic acid (ATRA) and anthracyclines. Nevertheless, the results observed in developing countries with the same regimen was poorer, mainly due to high early mortality mainly due bleeding. The International Consortium on Acute Promyelocytic Leukemia (IC-APL) is an initiative of the International Members Committee of the ASH and the project aims to reduce this gap through the establishment of international network, which was launched in Brazil, Mexico and Uruguay.

METHODS

The IC-APL treatment protocol is similar to the PETHEMA 2005, but changing idarubicin to daunorubicin. All patients with a suspected diagnosis of APL were immediately started on ATRA, while bone marrow samples were shipped to a national central lab where genetic verification of the diagnosis was performed. The immunofluorescence using an anti-PML antibody allowed a rapid confirmation of the diagnosis and, the importance of supportive measures was reinforced.

RESULTS

The interim analysis of 97 patients enrolled in the IC-APL protocol showed that complete remission (CR) rate was 83% and the 2-year overall survival and disease-free survival were 80% and 90%, respectively. Of note, the early mortality rate was reduced to 7.5%.

DISCUSSION

The results of IC-APL demonstrate the impact of educational programs and networking on the improvement of the leukemia treatment outcome in developing countries.

The coagulopathy of acute promyelocytic leukaemia revisited

Since the initial description of the disease, the life-threatening coagulopathy associated with acute promyelocytic leukaemia (APL) has been the defining clinical characteristic. Historically, this uncommon subtype of acute myeloid leukaemia has been associated with a high mortality rate during induction therapy, most frequently attributable to haemorrhage. Since the introduction of all-trans retinoic acid (ATRA) into the therapy of all patients with APL, disease-free survival and overall survival have improved dramatically, such that the disease is now highly curable. However, induction mortality remains a major problem and haemorrhage still accounts for the majority of such early deaths. Pathogenesis of the coagulopathy is complex and includes disseminated intravascular coagulation (DIC), fibrinolysis and proteolysis. As a result, while the predominant clinical manifestation of the coagulopathy is haemorrhage, thromboembolic events may occur both at presentation and during therapy. A major recent finding is the high expression of annexin II in the leukaemic cells from patients with APL. Annexin II is a protein with high affinity for plasminogen and tissue-type plasminogen activator (tPA), and also acts as a cofactor for plasminogen activation by tPA. As a result, both plasminogen and tPA are increased on the cell surface of the leukaemic cell, increasing plasmin activity. Annexin II is expressed in high amounts in cerebral microvascular endothelial cells, perhaps accounting for the relatively high incidence of intracranial haemorrhage in APL compared with other sites. Microparticles are cell-derived membrane fragments originating from normal cells or released from malignant cells involved in activating coagulation. Recent studies have found that microparticles containing tissue factor, tPA, plasminogen activator inhibitor-1 and annexin II have been found in the plasma of APL patients, suggesting a role in pathogenesis of the coagulopathy. Treatment of the coagulopathy remains primarily supportive. Aggressive transfusions of platelets and cryoprecipitate appear to be important. There is no clear role for the routine use of heparin or antifibrinolytic therapy. The most important factor may be the early introduction of ATRA at the first suspicion of a diagnosis of APL, before it is confirmed genetically.

A peptide derived from the nonreceptor binding region of urokinase plasminogen activator (uPA) inhibits tumor progression and angiogenesis and induces tumor cell death in vivo

Urokinase plasminogen activator (uPA) plays an important role in the progression of several malignancies including breast cancer. We have identified a noncompetitive antagonist of the uPA-uPAR interaction derived from a nonreceptor binding region of uPA (amino acids 136-143). This 8-mer capped peptide (A6) inhibited breast cancer cell invasion and endothelial cell migration in a dose-dependent manner in vitro without altering cell doubling time. Intraperitoneal administration of A6 resulted in a significant inhibition of tumor growth and suppressed the development of lymph node metastases in several models of breast cancer cell growth and metastasis. Large areas of tumor necrosis and extensive positive staining by TUNEL were observed on histological and immunohistochemical analysis of experimental tumor sections from A6-treated animals. A6 treatment also resulted in a decrease in factor VIII-positive tumor microvessel hot-spots. These results identify a new epitope in uPA that is involved in the uPA-uPAR interaction and indicate that an antagonist based on this epitope is able to inhibit tumor progression by modulating the tumor microenvironment in the absence of direct cytotoxic effects in vivo.

Diagnosis of septic pelvic thrombophlebitis by measurement of fibrinopeptide A

Septic pelvic thrombophlebitis is an uncommon but potentially life-threatening complication of puerperal endometritis. The lack of specific physical findings necessitates a diagnosis based by exclusion on the patient's response to anticoagulation. Fibrinopeptide A (FPA) is the first peptide cleaved from fibrinogen during thrombin-mediated fibrin generation. Because of its short half-life, FPA accurately reflects the level of ongoing fibrin generation. In a preliminary study of 40 puerperal patients, FPA successfully differentiated puerperal fever secondary to endometritis or abscess from fever responsive to a heparin trial. The mean FPA level in patients presumed to have septic pelvic thrombophlebitis was 23.8 ng/ml as opposed to 7 ng/ml in patients with endometritis. No patient with septic pelvic thrombophlebitis as diagnosed by her response to a heparin trial had a level of FPA less than 14 ng/ml. There was no overlap of FPA levels between patients with endometritis or abscess and septic pelvic thrombophlebitis. The data suggest further prospective evaluation of FPA for the diagnosis of septic pelvic thrombophlebitis is warranted.

Fibrin generation in normal pregnancy

Both clinical and laboratory findings suggest that pregnancy constitutes a hypercoagulable condition; yet none of the observed laboratory changes are specific for thrombosis. An essential step involves thrombin-mediated fibrin generation. In the process, fibrinopeptide A (FPA) is cleaved from fibrinogen. Using a radioimmune assay, FPA was determined prospectively in a longitudinal and cross-sectional fashion. Fibrinopeptide A increased significantly over control by the end of the first trimester, from 1.3 ng/ml to 2.8 ng/ml. It continued to increase until 30 to 32 weeks' gestation and then plateaued at 4.3 to 4.7 ng/ml. In the immediate postpartum period, FPA remains elevated. In conclusion, thrombin generation as reflected in FPA production is increased throughout pregnancy, thus confirming a hypercoagulable milieu.

Fibrin generation during the diabetic pregnancy

Fibrin catabolism was measured during the pregnancy of insulin-dependent diabetic women in both a longitudinal and cross sectional fashion. Samples of maternal peripheral venous blood were obtained in 20 pregnant diabetic women between 26 and 38 weeks' gestational age. Fibrinopeptide A, the first peptide cleaved from fibrinogen during thrombin-mediated catabolism, was measured by radioimmunoassay. Intra-assay and interassay variation for fibrinopeptide A in this laboratory were 2% and 4% respectively. Antithrombin III activity was determined by the method of Odegaard. The patients ranged from 23 to 36 years. Overall blood glucose control was good as reflected in near-normal HbA1 fasting plasma glucose values. The mean HbA1 +/- 1 standard deviation was 7.1% +/- 1.2%. The mean fasting plasma glucose concentration was 101.9 mg% +/- 21.5 mg%. Mean FPA for the diabetic women exceeded control values at each gestational period. Significant differences were found in four of the seven intervals. While the highest FPA was noted in a patient with advanced diabetic vasculopathy, exclusion of this patient did not alter the overall findings. The findings were striking and suggest the need for a prospective study designed to account for White's classification of diabetes and the degree of glucose control. Because complications of the diabetic pregnancy include an increased risk of hypertension in the mother and sudden, unexplained fetal loss, two complications associated with abnormal clotting, the increase in fibrin catabolism in patients in tight metabolic control would suggest that events other than glucose regulation impact upon fibrin catabolism and possibly pregnancy outcome in the diabetic mother.

Effect of Platelet Suppressants on Experimental Arterial Thrombosis

A reproducible model of platelet rich thrombi was produced in canine arteries by a previously described technique of intravascular insertion of metal tubing. The effect of platelet suppressants including sulfinpyrazone and ticrynafen, a clofibrate analog, on the rate and nature of thrombus formation was studied. ADP and epinephrine induced platelet aggregation of the animal's platelet rich plasma was monitored during the experiment. Platelet aggregation was impaired after the intravenous administration of either sulfinpyrazone (30 mg/kg body weight) or ticrynafen (100 mg/kg body weight). The rate of thrombus formation was not significantly altered by sulfinpyrazone when compared to the control, but histochemically, the thrombus studied showed a greatly diminished platelet content. In contrast, ticrynafen was able to prevent a complete occlusion of the involved vascular segment and a weak thrombus composed mostly of fibrin was produced instead. This effect of ticrynafen was dose related with minimal changes observed at a dose of 75 mg/kg. The results suggest that this arterial thrombosis model is of value in evaluating antithrombotic agents. They also indicate a potential value of ticrynafen as a therapeutic agent which should be further studied.

Thrombelastographic Effects of Dextran 70 on Human Blood

The effects of dextran was studied by thrombelastography (TEG) because it can graphically depict fibrin, formation and dissolution and plate 1st-fibrin interaction during clothing. Dextran 70 in concentrations of 1-8% ware added to samples of, native whole blood (WB), recalcified whole blood (RWB), platelet-rich plasma (PRP) and platelet-poor plasma (PPP) using buffered saline as control. Dextran produced an 13% reduction in clot Stiffness (MA) with native and celite activated WB. The same native WB shewed a 23? prolongation of clotting (R) and a 24% decrease in the rate of clot formation (α), while the celite activated WB R and α were reduced by 17% and 19% respectively. However, using RWB we found only a 10% reduction in MA as a result of dextran addition, suggesting that citrating and recalcification diminished the dextran effects. With FRF (platelets >560°000 dextran did not show any significant reduction in the measured parameters, uhiU FFP gavs the greatest response with a 36% decrease in MA. Results vere similar if FRF was obtained from subjects who had taken aspirin. This indicates the main action of dextran but to be on the fibrin network rather than on platelets or the plate let-fibrin interaction. though this effect is best seen when platelet concent: rations are low. Clot lysis by urokinase or streptokinase was accelerated in the presence of dextran but was reduced by increased platelet concentrations. These results suggest a direct effect of dextran on fibrin formation and may explain the antithrombotic effect of dextran in thit defective fibrin formation occurs.