Anti-fibrinolytic therapy with aminocaproic acid for the control of bleeding in thrombocytopenic patients

Challenges and Advances in Managing Thrombocytopenic Cancer Patients

Cancer patients have varying incidence, depth and duration of thrombocytopenia. The mainstay of managing severe chemotherapy-induced thrombocytopenia (CIT) in cancer is the use of platelet transfusions. While prophylactic platelet transfusions reduce the bleeding rate, multiple unmet needs remain, such as high residual rates of bleeding, and anticancer treatment dose reductions/delays. Accordingly, the following promising results in other settings, antifibrinolytic drugs have been evaluated for prevention and treatment of bleeding in patients with hematological malignancies and solid tumors. In addition, Thrombopoeitin receptor agonists have been studied for two major implications in cancer: treatment of severe thrombocytopenia associated with myelodysplastic syndrome and acute myeloid leukemia; primary and secondary prevention of CIT in solid tumors in order to maintain dose density and intensity of anti-cancer treatment. Furthermore, thrombocytopenic cancer patients are often prescribed antithrombotic medication for indications arising prior or post cancer diagnosis. Balancing the bleeding and thrombotic risks in such patients represents a unique clinical challenge. This review focuses upon non-transfusion-based approaches to managing thrombocytopenia and the associated bleeding risk in cancer, and also addresses the management of antithrombotic therapy in thrombocytopenic cancer patients.

The use of antifibrinolytics in pediatric patients with hypoproliferative thrombocytopenia

Despite the use of evidence-based platelet transfusion therapy during periods of hypoproliferative thrombocytopenia, a large proportion of pediatric hematology/oncology patients continue to suffer from clinically significant bleeding. Antifibrinolytic (AF) drugs have been shown in certain surgical and trauma settings to decrease bleeding, blood transfusion, and improve survival. We conducted a retrospective assessment of the safety of using AF drugs in pediatric patients with hypoproliferative thrombocytopenia at our center as well as the impact on bleeding occurrence and severity.

A new anti-fibrinolytic hemostatic compound 8-O-acetyl shanzhiside methylester extracted from Lamiophlomis rotata

BACKGROUND

Fibrinolysis prevents blood clots from growing and becoming problematic. Antifibrinolytics are used as inhibitors of fibrinolysis. Aprotinin was doubted after identification of major side effects, especially on kidney. Lysine analogues has their own defects and whether they are adequate substitutes for aprotinin is still under doubt. Lamiophlomis rotata (Benth.) Kudo. was previous found to have hemostatic activity. But the active compound in L. rotata and its hemostatic mechanism were unknown.

OBJECTIVES

To find the major hemostatic compound in L. rotata and identify its haemostasis mechanism.

METHODS

Traumatic hemorrhage model and coagulant activity assays were monitored in mice and platelets in drug treatment group and control group. Hyperfibrinolysis model was established by intravenous administration of urokinase in mice. Capillary blood clotting time (CBCT), activated partial thromboplastin time (APTT), prothrombin time (PT), thrombin time (TT), fibrinogen and euglobulin clot lysis time (ECLT) were measured.

RESULTS

The anti-fibrinolytic activity come from 8-O-Acetyl shanzhiside methylester (ASM) one of the highest iridoid glycosides contents in TIG extracted from L. rotata. ASM significantly (P<0.05) shorten CBCT and reduced blood loss volume in vivo, but did not influence mice APTT, PT or TT. In particular, it significantly prolonged ECLT in hyperfibrinolysis mice. It indicated that ASM could inhibit fibrinolysis. ASM was also effective in CBCT, traumatic bleeding volume and ECLT in hyperfibrinolysis mice model.

CONCLUSIONS

ASM was the major hemostatic compound in L. rotata. The haemostasis mechanism of ASM was achieved by anti-fibrinolytic activity. ASM was a new fibrinolysis inhibitor as iridoid glycoside compound.

Antifibrinolytics (lysine analogues) for the prevention of bleeding in people with haematological disorders

BACKGROUND

People with haematological disorders are frequently at risk of severe or life-threatening bleeding as a result of thrombocytopenia (reduced platelet count). This is despite the routine use of prophylactic platelet transfusions to prevent bleeding once the platelet count falls below a certain threshold. Platelet transfusions are not without risk and adverse events may be life-threatening. A possible adjunct to prophylactic platelet transfusions is the use of antifibrinolytics, specifically the lysine analogues tranexamic acid (TXA) and epsilon aminocaproic acid (EACA). This is an update of a Cochrane review first published in 2013.

OBJECTIVES

To determine the efficacy and safety of antifibrinolytics (lysine analogues) in preventing bleeding in people with haematological disorders.

SEARCH METHODS

We searched for randomised controlled trials (RCTs) in the Cochrane Central Register of Controlled Trials (The Cochrane Library 2016, Issue 3), MEDLINE (from 1946), Embase (from 1974), CINAHL (from 1937), the Transfusion Evidence Library (from 1950) and ongoing trial databases to 07 March 2016.

SELECTION CRITERIA

We included RCTs involving participants with haematological disorders, who would routinely require prophylactic platelet transfusions to prevent bleeding. We only included trials involving the use of the lysine analogues TXA and EACA.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened all electronically-derived citations and abstracts of papers, identified by the review search strategy, for relevancy. Two review authors independently assessed the full text of all potentially relevant trials for eligibility, completed the data extraction and assessed the studies for risk of bias using The Cochrane Collaboration's 'Risk of bias' tool. We requested missing data from one author but the data were no longer available. The outcomes are reported narratively: we performed no meta-analyses because of the heterogeneity of the available data.

MAIN RESULTS

We identified three new studies in this update of the review. In total seven studies were eligible for inclusion, three were ongoing RCTs and four were completed studies. The four completed studies were included in the original review and the three ongoing studies were included in this update. We did not identify any RCTs that compared TXA with EACA.Of the four completed studies, one cross-over TXA study (eight participants) was excluded from the outcome analysis because it had very flawed study methodology. Data from the other three studies were all at unclear risk of bias due to lack of reporting of study methodology.Three studies (two TXA (12 to 56 participants), one EACA (18 participants) reported in four articles (published 1983 to 1995) were included in the narrative review. All three studies compared the drug with placebo. All three studies included adults with acute leukaemia receiving chemotherapy. One study (12 participants) only included participants with acute promyelocytic leukaemia. None of the studies included children. One of the three studies reported funding sources and this study was funded by a charity.We are uncertain whether antifibrinolytics reduce the risk of bleeding (three studies; 86 participants; very low-quality evidence). Only one study reported the number of bleeding events per participant and there was no difference in the number of bleeding events seen during induction or consolidation chemotherapy between TXA and placebo (induction; 38 participants; mean difference (MD) 1.70 bleeding events, 95% confidence interval (CI) -0.37 to 3.77: consolidation; 18 participants; MD -1.50 bleeding events, 95% CI -3.25 to 0.25; very low-quality evidence). The two other studies suggested bleeding was reduced in the antifibrinolytic study arm, but this was statistically significant in only one of these two studies.Two studies reported thromboembolism and no events occurred (68 participants, very low-quality evidence).All three studies reported a reduction in platelet transfusion usage (three studies, 86 participants; very low-quality evidence), but this was reported in different ways and no meta-analysis could be performed. No trials reported the number of platelet transfusions per participant. Only one study reported the number of platelet components per participant and there was a reduction in the number of platelet components per participant during consolidation chemotherapy but not during induction chemotherapy (consolidation; 18 participants; MD -5.60 platelet units, 95% CI -9.02 to -2.18: induction; 38 participants, MD -1.00 platelet units, 95% CI -9.11 to 7.11; very low-quality evidence).Only one study reported adverse events of TXA as an outcome measure and none occurred. One study stated side effects of EACA were minimal but no further information was provided (two studies, 74 participants, very low-quality evidence).None of the studies reported on the following pre-specified outcomes: overall mortality, adverse events of transfusion, disseminated intravascular coagulation (DIC) or quality of life (QoL).

AUTHORS' CONCLUSIONS

Our results indicate that the evidence available for the use of antifibrinolytics in haematology patients is very limited. The trials were too small to assess whether or not antifibrinolytics decrease bleeding. No trials reported the number of platelet transfusions per participant. The trials were too small to assess whether or not antifibrinolytics increased the risk of thromboembolic events or other adverse events. There are three ongoing RCTs (1276 participants) due to be completed in 2017 and 2020.

Aminocaproic acid use in hospitalized patients with hematological malignancy: a case series

The antifibrinolytic aminocaproic acid is widely used in surgical settings to prevent blood loss and decrease transfusion requirements, and small observational studies have suggested that aminocaproic acid may be useful in the setting of malignancy-related bleeding. At our institution, aminocaproic acid is sometimes prescribed to patients with hematological malignancy who experience refractory thrombocytopenia with or without bleeding. We performed a 5-year retrospective review of 54 adult patients with 13 types of hematological malignancy who received aminocaproic acid at our institution. Indications for use included 31 (57.4%) for refractory thrombocytopenia with bleeding, 16 (29.6%) for refractory thrombocytopenia without bleeding, and 7 (13%) for bleeding alone. Patients received both oral and intravenous formulations. Administered doses ranged broadly and median duration of use was 6 days. Three patients (5.7%) developed deep venous thrombosis but none of the thrombotic events were clearly related to administration of aminocaproic acid. We conclude that aminocaproic acid may be a relatively safe and cost-effective adjunct treatment in the setting of bleeding related to the diagnosis and treatment of hematological malignancy. Prospective trials as well as formalized protocols for the use of aminocaproic acid may be indicated. Copyright © 2015 John Wiley & Sons, Ltd.

Antifibrinolytics (lysine analogues) for the prevention of bleeding in patients with haematological disorders

BACKGROUND

Patients with haematological disorders are frequently at risk of severe or life-threatening bleeding as a result of thrombocytopenia. This is despite the routine use of prophylactic platelet transfusions (PlTx) to prevent bleeding once the platelet count falls below a certain threshold. PlTx are not without risk and adverse events may be life-threatening. A possible adjunct to prophylactic PlTxs is the use of antifibrinolytics, specifically the lysine analogues tranexamic acid (TXA) and epsilon aminocaproic acid (EACA).

OBJECTIVES

To determine the efficacy and safety of antifibrinolytics (lysine analogues) in preventing bleeding in patients with haematological disorders.

SEARCH METHODS

We searched for randomised controlled trials (RCTs) in the Cochrane Central Register of Controlled Trials (CENTRAL Issue 12, 2012), MEDLINE (1948 to 10 January 2013), EMBASE (1980 to 10 January 2013), CINAHL (1982 to 10 January 2013), PubMed (e-publications only) and the Transfusion Evidence Library (1980 to January 2013). We also searched several international and ongoing trial databases to 10 January 2013 and citation-tracked relevant reference lists.

SELECTION CRITERIA

RCTs involving patients with haematological disorders, who would routinely require prophylactic platelet transfusions to prevent bleeding. We only included trials involving the use of the lysine analogues TXA and EACA.

DATA COLLECTION AND ANALYSIS

Two authors independently screened all electronically derived citations and abstracts of papers, identified by the review search strategy, for relevancy. Two authors independently assessed the full text of all potentially relevant trials for eligibility, completed the data extraction and assessed the studies for risk of bias using The Cochrane Collaboration's 'Risk of bias' tool. We requested missing data from one author but the data were no longer available. The outcomes are reported narratively: we performed no meta-analyses because of the heterogeneity of the available data.

MAIN RESULTS

Of 470 articles initially identified, 436 were excluded on the basis of the title and abstract. We reviewed 34 full-text articles from which four studies reported in five articles were eligible for inclusion. We did not identify any RCTs which compared TXA with EACA. We did not identify any ongoing RCTs.One cross-over TXA study (eight patients) was excluded from the outcome analysis because data from this study were at a high risk of bias. Data from the other three studies were all at unclear risk of bias due to lack of reporting of study methodology.Three studies (two TXA (12 to 56 patients), one EACA (18 patients)) reported in four articles (published 1983 to 1995) were included in the narrative review. All three studies compared the drug with placebo.All studies reported bleeding, but it was reported in different ways. All three studies suggested antifibrinolytics reduced the risk of bleeding. The first study showed a difference in average bleeding score of 42 in placebo (P) versus three (TXA). The second study only showed a difference in bleeding episodes during consolidation chemotherapy, with a mean of 2.6 episodes/patient (standard deviation (SD) 2.2) (P) versus a mean of 1.1 episodes/patient (SD 1.4) (TXA). The third study reported bleeding on 50% of days at risk (P) versus bleeding on 31% of days at risk (EACA).Two studies (68 patients) reported thromboembolism and no events occurred.All three studies reported a reduction in PlTx usage. The first study reported a difference of 222 platelet units (P) versus 69 platelet units (TXA). The second study only showed a difference in total platelet usage during consolidation chemotherapy, with a mean of 9.3 units (SD 3.3) (P) versus 3.7 (SD 4.1) (TXA). The third study reported one PlTx every 10.5 days at risk (P) versus one PlTx every 13.3 days at risk (EACA).Two studies reported red cell transfusion requirements and one study found a reduction in red cell transfusion usage.One study reported death due to bleeding as an outcome measure and none occurred.Only one study reported adverse events of TXA as an outcome measure and none occurred.None of the studies reported on the following pre-specified outcomes: overall mortality, adverse events of transfusion, disseminated intravascular coagulation (DIC) or quality of life (QoL).

AUTHORS' CONCLUSIONS

Our results indicate that the evidence available for the use of antifibrinolytics in haematology patients is very limited. The only available data suggest that TXA and EACA may be useful adjuncts to platelet transfusions so that platelet use, and the complications associated with their use, can be reduced. However, the trials were too small to assess whether antifibrinolytics increased the risk of thromboembolic events. Large, high-quality RCTs are required before antifibrinolytics can be demonstrated to be efficacious and safe in widespread clinical practice.

Epsilon aminocaproic acid reduces transfusion requirements in patients with thrombocytopenic hemorrhage

BACKGROUND

Epsilon aminocaproic acid (EACA) is an antifibrinolytic drug that has been used to control hemorrhage by stabilizing the thrombus. It has been used in thrombocytopenic patients largely on an empiric basis.

METHODS

Concerns regarding side effects have limited the use of this drug. The authors reviewed their experience with EACA at the Cleveland Clinic Foundation from 1997 to 2003.

RESULTS

Of 77 patients with thrombocytopenic hemorrhage, 51 (66%) patients achieved a complete response and 13 (17%) patients achieved a partial response, resulting in a decrease in platelet and red blood cell transfusions. Adverse effects were manageable in this set of patients with severe underlying disease.

CONCLUSIONS

Based on this experience, EACA may be a valuable adjunctive therapy in the treatment of patients with thrombocytopenic hemorrhage.

Management of bleeding emergencies: when to use recombinant activated Factor VII

Recombinant activated Factor VII (rVIIa) was originally released as a clotting factor, with use limited to a select group of patients who had few other treatment options. Due to the apparent ability of rVIIa to stop bleeding, no matter what the underlying cause, there is great interest in use of rVIIa in a wide range of bleeding patients. This article discusses rVIIa and its uses in a variety of patients, especially liver disease and trauma patients, and makes suggestions for appropriate use. Although most of the reports on rVIIa are anecdotes and case series, there is increasing data for clinical trials to help guide usage.

Management of bleeding in patients with advanced cancer

Bleeding occurs in up to 10% of patients with advanced cancer. It can present in many different ways. This article provides a qualitative review of treatment options available to manage visible bleeding. Local modalities, such as hemostatic agents and dressings, radiotherapy, endoscopic ligation and coagulation, and transcutaneous arterial embolization, are reviewed in the context of advanced cancer, as are systemic treatments such as vitamin K, vasopressin/desmopressin, octreotide/somatostatin, antifibrinolytic agents (tranexamic acid and aminocaproic acid), and blood products. Considerations at the end of life are described.

Liver biopsy complicated by hemorrhage in a patient with ARC syndrome

ARC syndrome is a rare disorder consisting of arthrogryposis, renal tubular acidosis and cholestatic liver disease. We report the case of a 5-week-old patient who underwent a percutaneous liver biopsy complicated by hemorrhage, and was subsequently diagnosed with ARC syndrome. A review of the literature demonstrates that these patients are at increased risk of bleeding caused by platelet dysfunction. The evaluation and management of unexpected hemorrhage in pediatric patients as a result of undiagnosed congenital bleeding problems is discussed.

Rare Bleeding Disorder Registry: deficiencies of factors II, V, VII, X, XIII, fibrinogen and dysfibrinogenemias

A North American registry for rare bleeding disorders [factor (F)II, factor (F)VII, factor (F)X, factor (F)V, factor (F)XIII, fibrinogen deficiencies and dysfibrinogenemias] was established to gather information about disease prevalence, genotyping frequency, diagnostic events, clinical manifestations, treatment and prophylaxis strategies, as well as disease- and treatment-related complications. Questionnaires were sent to 225 hemophilia treatment centers in the USA and Canada. Among 26% of responding centers, 294 individuals [4.4% of the registered children (200/4583) and 2.4% of adults (94/3809)] were diagnosed with one or more of the rare bleeding disorders (RBDs) included in this survey. The ethnic distribution for each disorder paralleled that of the general US population with the exception of the disproportionately large number of Latinos with FII deficiency. Only 5.4% of affected individuals were genotyped. An abnormal preoperative bleeding screen most often led to diagnosis. The most common coagulopathy was FVII deficiency; however, 40% of homozygous patients were asymptomatic. FX and FXIII deficiencies caused the most severe bleeding manifestations. Among all RBDs, the most common sites of bleeding were skin and mucus membranes. Multiple products were used to treat hemorrhage; however, half of the bleeding episodes required no therapy. The majority of patients suffered no long-term complications from hemorrhage. Treatment-related complications included viral seroconversion, anemia, allergic reactions and venous access device-related events. This registry provides the most comprehensive information to date about North American individuals with RBDs and could serve as an important resource for both basic scientist and clinician.

Excessive fibrin after cataract surgery associated with aminocaproic acid use

A 78-year-old woman developed a severe fibrinous anterior chamber reaction 1 day after uneventful clear corneal incision cataract extraction with intraocular lens implantation. There was no history of uveitis or diabetes, and the fibrin responded immediately to topical steroids. The patient was followed closely to rule out endophthalmitis. The only risk factor identified was the use of systemic aminocaproic acid as prophylaxis for bleeding in chronic leukemia.

Algorithm for managing the platelet refractory patient

Refractoriness to platelet transfusions continues to be a major problem for many thrombocytopenic patients. A proposed algorithm for managing these patients is presented which proceeds from easily instituted changes in platelet transfusion therapy such as provision of ABO-compatible and "fresh" platelet transfusions to the more difficult and costly process of selecting compatible platelets for patients who are documented to be alloimmunized. For nonimmunized platelet refractory recipients, multiple clinical and drug factors that may adversely effect transfusion responses have been identified. Identifying which of these factors are causally associated with poor platelet responses in any given patient remains a substantial challenge.

A multicenter trial of 6-aminocaproic acid (Amicar) in the prevention of bleeding in infants on ECMO

BACKGROUND/PURPOSE

Intracranial hemorrhage (ICH), is a major source of morbidity and the leading cause of death in neonates treated with extracorporeal membrane oxygenation (ECMO). Anecdotal reports have suggested that epsilon-aminocaproic acid (EACA) can decrease the risk of ICH. The purpose of this study was to evaluate, in a multiinstitutional, prospective, randomized, blinded fashion, the effect of EACA on the incidence of hemorrhagic complications in neonates receiving ECMO.

METHODS

All neonates (except congenital diaphragmatic hernia) who met criteria for ECMO at three institutions were eligible for enrollment. EACA (100 mg/kg) or placebo was given at the time of cannulation followed by 25 mg/kg/h for 72 hours. Bleeding complications, transfusion requirements, and thrombotic complications were recorded. Post-ECMO imaging included head ultrasound scan computed tomography (CT) scan, and duplex ultrasound scan of the inferior vena cava and renal vessels.

RESULTS

Twenty-nine neonates were enrolled (EACA, 13 and placebo, 16). Five (17.2%) patients had a significant (grade 3 or larger) ICH. There was no statistical difference in the incidence of significant ICH in patients who received EACA (23%) versus placebo (12.5%). Septic patients accounted for all of the ICH in the EACA group. Thrombotic complications (aortic thrombus and SVC syndrome) developed in two patients from the placebo group. There was no difference in thrombotic circuit complications between groups.

CONCLUSIONS

Our results suggest that the use of EACA in neonates receiving ECMO is safe but may not decrease the overall incidence of hemorrhagic complications.

Acute leukaemia in Jehovah's Witnesses

The refusal of Jehovah's Witnesses with leukaemia to accept transfusion provides a major clinical challenge because of the myelosuppressive effects of chemotherapy. Experience in treating five such patients is described. Two patients with acute lymphoblastic leukaemia (ALL) achieved remission following chemotherapy, the first without transfusion support, the second, a minor, receiving transfusion under a court order: the first patient remains in remission 5 years later, whereas the second subsequently relapsed and died. Of three patients with acute myeloid leukaemia (AML), two received chemotherapy: one died of anaemia during induction chemotherapy whereas the second eventually consented to transfusion but died of refractory leukaemia. The third patient died of anaemia despite erythropoietin. We feel Jehovah's Witnesses should not be denied antileukaemic therapy if they fully understand the risks involved. Minimizing phlebotomy, use of antifibrinolytic agents and growth factors may make chemotherapy feasible, especially in ALL where remission may be induced with less myelosuppressive agents. The outlook for those with AML treated with conventional chemotherapy appears poor; alternative approaches to treatment should be considered in these patients.

Rhabdomyolysis induced by epsilon-aminocaproic acid

OBJECTIVE

To report a case of rhabdomyolysis associated with epsilon-aminocaproic acid (epsilon-ACA).

CASE SUMMARY

A 33-year-old female patient with chronic granulocytic leukemia was treated with epsilon-ACA for approximately 3.5 months for thrombocytopenic bleeding. The initial dosage was 4 g po q6h. One month after an increase in dosage to 5 g po 14h the patient developed severe lower extremity myalgia and marked weakness. Laboratory investigations revealed an elevated creatine kinase (CK), lactate dehydrogenase (LDH). aspartate aminotransferase (AST), and myoglobinemia. Epsilon-ACA was thought to be the causative agent and was discontinued. The patient received intravenous fluids to minimize renal damage due to myoglobin. Serum enzyme concentrations did not return to normal. The patient died of a central nervous system hemorrhage 1 week after the epsilon-ACA was discontinued.

DISCUSSION

There were 31 cases of epsilon-ACA-induced myopathies published in the literature (MEDLINE) from 1972 to June 1995. Of these, 10 cases were reviewed. In all cases, patients received epsilon-ACA in doses ranging from 16 to 36 g/d for more than 28 days. Clinical findings varied from extreme muscle weakness to myopathic changes in electromyelograms. All patients recovered following discontinuation of epsilon-ACA.

CONCLUSIONS

Long-term therapy with high-dose epsilon-ACA may produce muscle weakness or rhabdomyolysis. Patients who require long-term, high-dose epsilon-ACA therapy should be monitored for myoglobinuria and changes in serum CK, LDH, and AST, for myoglobinemia, for decreases in muscle strength, and/or for myalgia. Significant changes in these parameters compared with baseline values should suggest a need to discontinue epsilon-ACA therapy.

Incidence and outcome of overt gastrointestinal bleeding in patients undergoing bone marrow transplantation

The purpose of this study was to determine the prevalence, clinical patterns, and outcomes of gastrointestinal bleeding in consecutive patients treated at one bone marrow transplant center. We reviewed the clinical course of 579 consecutive bone marrow transplant recipients who underwent therapy from January 1986 through December 1993. These patients were evaluated for overt gastrointestinal bleeding, defined as hematemesis, melena, hematochezia, or a combination. Overt gastrointestinal bleeding was defined in 43 of 579 patients (7.4%), including 25 men and 18 women undergoing transplantation for hematologic disorders (N = 29) and solid tumors (N = 14). After high-dose cytotoxic chemotherapy, patients were given allogeneic (N = 10) or autologous (N = 33) hematopoietic progenitor cell support obtained from bone marrow, peripheral blood, or both. H2 blockers, sucralfate, or a combination were administered to all patients as prophylactic therapy. Bleeding manifestations included hematemesis(N = 24, melena (N = 8), hematochezia (N = 7), and combinations (N = 4). The median time from bone marrow infusion to the onset of overt gastrointestinal bleeding was 7.5 days (range: 0-45 days). Fourteen patients had evidence of orthostatic hypotension attributable to gastrointestinal bleeding. Esophagogastroduodenoscopy was performed in 26 patients; 18 had diffuse esophagitis and gastritis. Two patients with bleeding ulcers underwent successful electrocautery. Colonoscopy was performed in five patients and revealed a cecal ulcer in one subject, tumor recurrence in one patient, and colitis in another. No patients underwent surgical intervention. Only ine patient died as a result of gastrointestinal bleeding. Overt gastrointestinal bleeding is uncommon in patients undergoing bone marrow transplantation; most episodes are self-limited and do not contribute to overall mortality. Endoscopy is primarily diagnostic as most patients do not have lesions amenable to therapeutic procedures.

Thrombocytopenia. Issues in diagnosis and therapy

Thrombocytopenia is defined by clinical characteristics and pathophysiologic mechanisms. The patient with thrombocytopenia often presents diagnostic and management challenges simultaneously. The differential diagnosis is broad because the disorders leading to thrombocytopenia are diverse, with failed production at one extreme and accelerated destruction at the other. Reviewed in terms of diagnosis and therapy are pseudothrombocytopenia, dilutional thrombocytopenia, and the three major mechanisms: decreased production, altered distribution, and increased destruction.

Inhibitory effects of lysine analogues on t-PA induced whole blood clot lysis

The lysine analogues epsilon-aminocaproic acid (EACA) and trans-4-amino-methyl cyclohexane carboxylic acid (AMCA) are used to prevent excessive bleeding in patients with coagulopathies, such as hemophilia and thrombocytopenia, or in those who have received tissue plasminogen activator (t-PA). However, their relative efficacy in inhibiting lysis of clots that have been formed in the presence of exogenous t-PA or that have been formed and then exposed to exogenous t-PA has not been well characterized. The present study utilized blood from normal volunteers and 125I-fibrinogen in a dilute whole blood clot assay to determine the relative concentrations of lysine analogues required for inhibition of clot lysis induced by exogenous t-PA. AMCA (0.06 mM) and EACA (0.6 mM) were effective in prolonging clot lysis if (1) whole blood clots were formed and then exposed to a lysine analogue and exogenous t-PA or if (2) whole blood clots were formed in the presence of exogenous t-PA and a lysine analogue. However, their inhibitory effect was markedly reduced if clots were formed in the presence of t-PA and then exposed to either of the lysine analogues. The analogues did not inhibit the initial binding of t-PA to fibrin. They did inhibit binding of plasminogen to fibrin as well as the activation of plasminogen by t-PA in the absence of fibrin. The data suggest that lysine analogues, even at low concentrations, reduce the rate of t-PA induced whole blood clot lysis by several mechanisms.

Tranexamic acid therapy in acute myeloid leukemia: possible reduction of platelet transfusions

We studied the clinical efficacy and safety of the antifibrinolytic drug tranexamic acid (TA) in patients undergoing chemotherapy for acute leukemia. 54 newley diagnosed AML patients were treated with 1 g of TA every 6 hours until the platelet count rose to above 20 x 10(9)/l. Platelet transfusions were given, irrespective of the count, only when oral, mucosal or significant skin bleeding manifestations were observed. During induction, the average number of days with thrombocytopenia below 20 x 10(9)/l was 14.4 +/- 7.4 and 4.6 +/- 4.1 transfusions were given in each course. During consolidation, the average number of thrombocytopenic days was 8.4 +/- 8.5 and only 1.7 +/- 1.8 transfusions were administered. In 11.5% of the induction and 32.1% of the consolidation courses, no platelet support was required. TA was tolerated very well and no side effects or thromboembolic complications were observed. Only in 6 of the 78 induction courses did a major bleeding event occur and there were none in any of the 53 consolidation courses. Thus it seems that TA therapy allowed a significant reduction in the use of platelet transfusions without submitting the patients to greater bleeding risks.