Occurrence of thrombotic events in acute promyelocytic leukemia correlates with consistent immunophenotypic and molecular features

Acute cardiovascular complications of disseminated intravascular coagulation in acute myeloid leukemia

BACKGROUND

Disseminated intravascular coagulation (DIC) is a common complication of all leukemia subtypes, but it is an especially prominent feature of Acute Myeloid Leukemias (AML). DIC complicating AML can lead to a variety of complications, however, its association with acute cardiovascular complications has not been reported before.

METHODS

National Inpatient Sample Database was used to procure individuals with AML, and baseline demographics and comorbidities were collected using ICD-10-DM codes. Patients were stratified into those with and without DIC. Greedy propensity matching using R was performed to match the two cohorts in 1:1 ratio on age, gender, and fifteen other baseline comorbidities. Univariate analysis pre and post-match along with binary logistic regression analysis post-match were used to analyze outcomes.

RESULTS

Out of a total of 37,344 patients with AML, 996 had DIC. DIC patients were younger, predominantly males, and had lower prevalence of baseline cardiovascular comorbidities. DIC patients had statistically significant higher mortality (30.2 % vs 7.8 %), acute myocardial infarction (5.1 % vs 1.8 %), acute pulmonary edema (2.3 % vs 0.7 %), cardiac arrest (6.4 % vs 0.9 %), and acute DVT/PE (6.6 % vs 2.7 %). Logistic regression model after matching showed similar outcomes along with significantly higher rates of acute heart failure in DIC patients.

CONCLUSION

These findings highlight the importance of close cardiovascular monitoring and prompt recognition of complications in AML patients with DIC. The underlying mechanisms involve a complex interplay of procoagulant factors, cytokine release, and endothelial dysfunction. Further studies are needed to develop targeted interventions for prevention and management of these complications.

Cancer-associated thrombosis in hematologic malignancies

Patients with hematologic malignancies are often complicated not only by severe bleeding due to thrombocytopenia and disseminated intravascular coagulation but also by thromboembolic events, just like in patients with solid cancers, and these events can negatively impact patient outcomes. Nevertheless, the prevention and treatment of cancer-associated thrombosis (CAT) in hematologic malignancies has not been adequately investigated due to the limited size, heterogeneity, and unique pathophysiology of the patient population. This article summarizes the current understanding, risk factors, prediction models, and optimal prevention and treatment strategies of CAT in hematologic malignancies on a disease-by-disease basis, including acute leukemia, lymphoma, myeloma, and myeloproliferative neoplasms. Specific considerations of novel molecular targeted therapeutics introduced in recent years, such as immunomodulatory drugs and tyrosine kinase inhibitors, are also discussed based on the latest clinical trials.

The ISTH DIC-score predicts early mortality in patients with non-promyelocitic acute myeloid leukemia

Coagulation disorders frequently complicate the clinical course of acute myeloid leukemia (AML) patients. This study examined the frequency and prognostic significance, with regards of early mortality, of the presence of overt disseminated intravascular coagulation (DIC) at AML diagnosis and its correlation with clinical and biological characteristics. A retrospective analysis of 351 newly diagnosed non-promyelocytic AML patients was conducted, utilizing the 2018 ISTH DIC-Score criteria to evaluate the presence of overt DIC at AML onset. The study cohort had a median age of 65 years with a predominance of male gender (59 %). Overt DIC was present in 21 % of cases and was associated with advanced age, comorbidities, poor performance status, hyperleukocytosis, LDH levels, NPM1 mutations, expression of CD33 and CD4, and lack of expression of CD34. With a median follow-up of 72 months (3-147 months), the 6-year overall survival (OS) was 17.4 %, with patients having overt DIC showing significantly poorer outcomes (7.2 % compared to 20.3 % of those without DIC, p < 0.001). Patients with overt DIC showed markedly high early mortality rates at 30 (42.5 % vs 8 %), 60 (49.3 % vs 16.9 %), and 120 days (64.4 % vs 25.6 %) from disease onset. In multivariate analysis overt DIC retained its independent prognostic value for early mortality. In conclusion, the prevalence and clinical relevance of DIC in non-promyelocytic AML is not negligible, underlining its potential as an unfavorable prognostic marker. In newly diagnosed patients with AML, early recognition and measure to counteract coagulation disturbances might help mitigate the elevated mortality risk associated with DIC.

Cellular hierarchy insights reveal leukemic stem-like cells and early death risk in acute promyelocytic leukemia

Acute promyelocytic leukemia (APL) represents a paradigm for targeted differentiation therapy, with a minority of patients experiencing treatment failure and even early death. We here report a comprehensive single-cell analysis of 16 APL patients, uncovering cellular compositions and their impact on all-trans retinoic acid (ATRA) response in vivo and early death. We unveil a cellular differentiation hierarchy within APL blasts, rooted in leukemic stem-like cells. The oncogenic PML/RARα fusion protein exerts branch-specific regulation in the APL trajectory, including stem-like cells. APL cohort analysis establishes an association of leukemic stemness with elevated white blood cell counts and FLT3-ITD mutations. Furthermore, we construct an APL-specific stemness score, which proves effective in assessing early death risk. Finally, we show that ATRA induces differentiation of primitive blasts and patients with early death exhibit distinct stemness-associated transcriptional programs. Our work provides a thorough survey of APL cellular hierarchies, offering insights into cellular dynamics during targeted therapy.

Arteriovenous thrombosis, a complication of induction therapy with all-trans retinoic acid for acute promyelocytic leukemia: A case report

We report a case of arterial and venous thrombosis during induction therapy. This case emphasizes considering some degree of caution for thrombotic events in APL patients which was represented in our case as abdominal pain. Rapid initiation of anticoagulation and preventive measures is suggested for better management of the condition.

The Coagulopathy of Acute Promyelocytic Leukemia: An Updated Review of Pathophysiology, Risk Stratification, and Clinical Management

Acute promyelocytic leukemia (APL) has a well-established mechanism and a long-term prognosis that exceeds that of any other acute leukemia. These improving outcomes are due, in part, to all-trans retinoic acid (ATRA) and arsenic trioxide (ATO), two targeted and highly active agents in this disease. However, there remains a considerable morbidity and mortality risk in APL secondary to clinically significant hemorrhagic and/or thrombotic events. Prevention and treatment of these coagulopathic complications remain significant impediments to further progress in optimizing outcomes for patients with APL. Moreover, the relative rarity of APL hinders adequately powered randomized controlled trials for evaluating APL coagulopathy management strategies. This review draws from peer-reviewed works falling between initial descriptions of APL in 1957 and work published prior to January 2023 and provides an updated overview of the pathophysiology of hemorrhagic and thrombotic complications in APL, outlines risk stratification parameters, and compiles current clinical best practices. An improved understanding of the pathophysiologic mechanisms driving hemorrhage and thrombosis along with the completion of well-designed trials of management strategies will assist clinicians in developing interventions that mitigate these devastating complications in an otherwise largely curable disease.

Simplified predictive scores for thrombosis and bleeding complications in newly diagnosed acute leukemia patients

BACKGROUND

Bleeding and thrombotic complications are the leading causes of death in acute leukemia patients. The Conventional International Society of Thrombosis and Haemostasis Disseminated Intravascular Coagulation (ISTH DIC) scoring system is utilized to assess DIC diagnoses in various conditions. Nevertheless, limited studies have tested the system's accuracy in predicting thrombo-hemorrhagic events in individuals with acute leukemia. This study aimed to (1) validate the ISTH DIC scoring system and (2) propose a new Siriraj Acute Myeloid/Lymphoblastic Leukemia (SiAML) bleeding and thrombosis scoring system for thrombohemorrhagic risk assessment in acute leukemia.

METHODS

We conducted a retro-prospective observational study of newly diagnosed acute leukemia patients between March 2014 and December 2019. We recorded thrombohemorrhagic episodes within 30 days postdiagnosis and DIC profiles, including prothrombin time, platelet level, D-dimer, and fibrinogen. The sensitivities, specificities, positive and negative predictive values, and areas under receiver operating characteristic curves for the ISTH DIC and SiAML scoring systems were calculated.

RESULTS

In all, 261 acute leukemia patients were identified: 64% with acute myeloid leukemia, 27% with acute lymphoblastic leukemia, and 9% with acute promyelocytic leukemia. Overall bleeding and thrombotic events were 16.8% and 6.1%, respectively. With a cutoff of 5 for the ISTH DIC score, the sensitivity and specificity for bleeding prediction were 43.5% and 74.4%, respectively, while the corresponding values for thrombotic prediction were 37.5% and 71.8%, respectively. D-dimer > 5000 µg FEU/L and fibrinogen ≤ 150 mg/dL were significantly associated with bleeding. A SiAML-bleeding score was calculated using these factors, with a sensitivity and specificity of 65.2% and 65.6%, respectively. Conversely, D-dimer > 7000 µg FEU/L, platelet > 40 × 10⁹/L, and white blood cell level > 15 × 10⁹/L were significant variables related to thrombosis. Using these variables, we established a SiAML-thrombosis score with a sensitivity and specificity of 93.8% and 66.1%, respectively.

CONCLUSIONS

The proposed SiAML scoring system might be valuable for prognosticating individuals at risk for bleeding and thrombotic complications. Prospective validation studies are needed to verify its usefulness.

Clinical outcomes of therapeutic leukapheresis in acute promyelocytic leukemia: A single-center retrospective cohort study

BACKGROUND

In acute promyelocytic leukemia (APL), increased cell burden in the peripheral blood due to either the disease itself or early treatment with all-trans retinoic acid could cause hyperleukocytosis (HL) before induction chemotherapy. However, therapeutic leukapheresis has seldom been used because of concerns of subsequent coagulopathy after this invasive procedure. The aim of this study was to evaluate the effects of leukapheresis in APL, especially for efficacy and safety.

METHODS

We retrospectively analyzed newly diagnosed patients with APL from January 2009 to March 2022. Among 323 patients, 85 had white blood cell count above 40 × 10⁹/L before induction chemotherapy. Thirty-nine patients were initially treated with leukapheresis, whereas the other 46 were not. Clinical and laboratory parameters between these groups were compared.

RESULTS

There was a trend toward favorable 30-day survival rate for the leukapheresis group compared with the non-leukapheresis group (76.9% and 67.4%; P = 0.24). The complications including subsequent intensive unit care (P = 0.23), severe hemorrhagic events (P = 0.13) showed no significant differences between the two groups. The patients were divided into subcohorts, and the survival rates of the leukapheresis and non-leukapheresis groups were 92.3% (95% confidence interval [CI], 77.8%-100.0%) versus 58.3% (95% CI, 38.6%-78.1%) (P = 0.03) in "sequential HL" and 76.7% (95% CI, 61.5%-91.8%) versus 54.8% (95% CI, 37.3%-72.4%) (P = 0.03) in "symptomatic HL," respectively. Moreover, in the "sequential HL" subcohort, the cumulative incidence of differentiation syndrome and following adverse events were significantly lower in the leukapheresis group.

CONCLUSIONS

In APL with "sequential HL" or "symptomatic HL" from either the disease itself or the effect of all-trans retinoic acid, therapeutic leukapheresis could be applied to reduce leukemic cell burden without significant risks.

Multi-omics and machine learning reveal context-specific gene regulatory activities of PML::RARA in acute promyelocytic leukemia

The PML::RARA fusion protein is the hallmark driver of Acute Promyelocytic Leukemia (APL) and disrupts retinoic acid signaling, leading to wide-scale gene expression changes and uncontrolled proliferation of myeloid precursor cells. While known to be recruited to binding sites across the genome, its impact on gene regulation and expression is under-explored. Using integrated multi-omics datasets, we characterize the influence of PML::RARA binding on gene expression and regulation in an inducible PML::RARA cell line model and APL patient ex vivo samples. We find that genes whose regulatory elements recruit PML::RARA are not uniformly transcriptionally repressed, as commonly suggested, but also may be upregulated or remain unchanged. We develop a computational machine learning implementation called Regulatory Element Behavior Extraction Learning to deconvolute the complex, local transcription factor binding site environment at PML::RARA bound positions to reveal distinct signatures that modulate how PML::RARA directs the transcriptional response.

Realgar (As4S4), a traditional Chinese medicine, induces acute promyelocytic leukemia cell death via the Bcl-2/Bax/Cyt-C/AIF signaling pathway in vitro

Acute promyelocytic leukemia (APL) is a specific subtype of acute myelogenous leukemia (AML) characterized by the proliferation of abnormal promyelocytes. Realgar, a Chinese medicine containing arsenic, can be taken orally. Traditional Chinese medicine physicians have employed realgar to treat APL for over a thousand years. Therefore, realgar may be a promising candidate for the treatment of APL. Nevertheless, the underlying mechanism behind realgar therapy is largely unclear. The present study aimed to investigate the effect of realgar on cell death in the APL cell line (NB4) in vitro and to elucidate the underlying mechanism. In this study, after APL cells were treated with different concentrations of realgar, the cell survival rate, apoptotic assay, morphological changes, ATP levels and cell cycle arrest were assessed. The expression of Bcl-2, Bax, Cytochrome C (Cyt-C) and apoptosis-inducing factor (AIF) at the mRNA and protein levels were also measured by immunofluorescence, quantitative PCR (qPCR) and Western blotting. We found that realgar could significantly inhibit APL cell proliferation and cell death in a time- and dose-dependent manner. Realgar effectively decreased the ATP levels in APL cells. Realgar also induced APL cell cycle arrest at the S and G2/M phases. Following realgar treatment, the mRNA and protein levels of Bcl-2 were significantly downregulated, whereas the levels of Bax, Cyt-C, and AIF were significantly upregulated. In summary, realgar can induce APL cell death via the Bcl-2/Bax/Cyt-C/AIF signaling pathway, suggesting that realgar may be an effective therapeutic for APL.

Predictive factors for differentiating thrombohemorrhagic disorders in high-risk acute promyelocytic leukemia

INTRODUCTION

Acute promyelocytic leukemia (APL) is often accompanied by potentially fatal coagulopathy, especially in high-risk APL. Bleeding, particularly severe bleeding is the leading cause of early death (ED). Meanwhile, thrombosis, the other major coagulopathic complication, is being increasingly recognized. However, predictors of thrombohemorrhagic disorders are still not well investigated.

MATERIALS AND METHODS

In this study, we retrospectively studied 83 patients with high-risk APL and categorized them into severe bleeding, thrombosis and no evident events groups.

RESULTS

Severe bleeding was observed in 15 patients, nearly half of whom died of hemorrhage, while thrombosis was observed in 12 patients. Risk factor analysis showed that high WBC (>58.76 × 10⁹/L) (p = 0.001) and prolonged PT (>17.7 s) (p = 0.015) could be independent predictors for severe bleeding, while high WBC/D-dimer>5.12 (p = 0.002) and low D-dimer/FIB<5.14 (p = 0.03) could be independent predictors for thrombosis in high-risk APL patients. Moreover, there are significant differences in WBC/D-dimer and D-dimer/FIB between DIC and Non-DIC groups (p < 0.001). Notably, we found that the WBC/D-dimer was dramatically higher in the thrombotic group than in the other two groups at the time of admission or during the first week of induction therapy.

CONCLUSIONS

High WBC and prolonged PT could predict severe bleeding in high-risk APL patients, while high WBC/D-dimer and low D-dimer/FIB could be independent predictors for thrombosis. For high-risk APL, WBC/D-dimer and D-dimer/FIB are also beneficial in the diagnosis of DIC. WBC/D-dimer might help early identification of thrombosis at the time of admission or during the first week of induction therapy.

Gangrenous Ischemic Colitis Due to Acute Promyelocytic Leukaemia, and Myelofibrosis in a 62-year-old Man Suffering from ESRD; Case Report

Introduction and importance

Ischemic colitis, also rare, is the most common ischemic pathology of the digestive system. It usually affects the ageing population and those suffering from end-stage renal disease (ESRD), hypertension, and heart failure. Its incidence varies from 4.5 to 44 cases per 100,000 annually.

Case presentation

We have reported a case of gangrenous colitis in a 62-year-old man suffering from acute promyelocytic leukaemia (APL) and myelofibrosis. He had hypertension and ESRD due to obstructive uropathy from seven years ago in his past medical history. His recurrent constitutional symptoms and persistent leukocytosis of more than 20,000 in μL was always treated as catheter-related infection or sepsis until acute abdomen emerged. The surgical team encountered a vast gangrenous right hemicolon. The leukocytosis did not resolve. Thus, the haematological investigations proved APL with myelofibrosis. The affected colon was free of leukemic infiltration.

Clinical discussion

Hypoperfusion due to ESRD and hemodialysis accompanied with malignancy induced hypercoagulative state provided a context in which small vessels of the bowel were obstructed.

Conclusion

Malignancies are associated with thrombophilia, and colonic involvement is not always related to lymphatic infiltration in leukaemia patients.

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Ischemic colitis, also rare, is the most common ischemic pathology of the digestive system.

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Not every leukocytosis should be viewed as sepsis.

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Although rare, acute promyelocytic leukaemia can be accompanied by myelofibrosis.

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Ischemic colitis may be a result of a hypercoagulable state caused by leukaemias, not necessarily leukaemic invasion.

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The cecum is within a watershed of the colon in which incomplete anastomoses of the marginal arteries make its blood supply poor and vulnerable to ischemia.

Acute promyelocytic leukemia presenting as recurrent venous and arterial thrombotic events: a case report and review of the literature

Acute promyelocytic leukemia (APL) is a distinct subtype of acute myeloid leukemia characterized by a translocation of chromosomes 15 and 17, creating an alternation in the retinoic acid receptor-alpha (RAR-alpha) gene. This leads to excessive medullary production of promyelocytic blasts, which are frequently associated with the hemorrhagic complications seen in APL. In contrast, APL-associated thrombosis occurs much less frequently and is an underappreciated life-threatening manifestation of the disease. Most thrombotic events occur during induction chemotherapy with all-transretinoic acid and are rarely seen as the initial presentation on APL. Here we report an exceedingly rare case of a patient with recurrent venous and arterial thrombotic events, including deep vein thrombosis, bilateral segmental pulmonary embolism, an ischemic stroke, splenic infarcts, and renal infarcts, later found to have APL. We aim to discuss the most recent understanding of the pathogenesis of APL-associated thrombosis and to summarize the literature of this rare presentation of APL.

Coagulopathy in Acute Promyelocytic Leukemia: Can We Go Beyond Supportive Care?

Acute promyelocytic leukemia (APL) is characterized by frequent complications due to a distinct coagulopathy. While advances in treatments have improved long-term survival, hemorrhagic and thrombotic complications remain the most common causes of death and morbidity. Improved understanding of the mechanisms of the coagulopathy associated with APL may lead to therapeutic interventions to mitigate the risk of hemorrhage and thrombosis.

Advances in the management of coagulopathy in acute promyelocytic leukemia

Since the introduction of all-trans retinoic acid and, more recently, arsenic trioxide into the therapy of acute promyelocytic leukemia (APL), significant improvements in patient outcomes have been achieved, and this disease has become the most curable subtype of acute myeloid leukemia. However, while primary leukemia resistance has virtually disappeared, a sizable fraction of APL patients still die before or during induction therapy. Hemorrhagic death still remains the major problem during this early phase of treatment and, to a lesser extent, deaths due to infection, differentiation syndrome and other causes. Patients with APL typically present with a range of laboratory abnormalities consistent with the diagnosis of disseminated intravascular coagulation and hyperfibrinolysis. This APL-associated coagulopathy, as a result of a dysregulation of the hemostatic system due to the imbalance between procoagulant, anticoagulant and profibrinolytic mechanisms, may show a variety of clinical manifestations, ranging from minimal bleeding or localized thrombosis to lethal or life-threatening hemorrhages or thrombotic events that sometimes occur concomitantly. Hemorrhagic events are the most common cause of death associated with APL coagulopathy, but thrombosis, a less recognized and probably underestimated life-threatening manifestation of the thrombo-hemorrhagic syndrome, is also a non-negligible cause of morbidity and mortality in patients with APL. In this article, we aim to discuss recent advances in the knowledge of pathogenesis, predictors of thrombo-hemorrhagic events, management of coagulopathy associated with APL and the controversial issues that still persist.

Risk factors of thrombosis in Chinese subjects with acute promyelocytic leukemia

BACKGROUND

Acute promyelocytic leukemia (APL) is a special type of acute myeloid leukemia Thrombosis is at increased risk complication in patients with this disease. However, the risk factors of thrombosis related to Chinese APL patients are not fully understood.

METHODS

In this study, clinical and laboratory data of 44 consecutively Chinese APL patients were collected and analyzed.

RESULTS

One arterial and 6 venous thrombosis occurred in 44 patients, including 22 males and 22 females, with a median age of 44 years (range from 18 to 74 years). The ratio of male and female gender, age, white blood cell count, hemoglobin, platelets, disease risk stratification, CD2, Khorana score, differentiation syndrome (DS) and gene mutation related to prognosis of APL, including DNMT3A, TET2, IDH1, IDH2, NRAS and ASXL1 in the two groups with and without thrombosis were not statistically significant. The detection rate of PAI-1 genotype 4G4G was 71.4% (5/7) in 7 patients with thrombosis, while the detection rate of PAI-1 genotype 4G4G in 37 patients without thrombosis was 8.1% (3/37). The differences between the two groups in WT-1 (P = 0.01), PAI-1 4G4G (P = 0.0009), bcr3 (P = 0.027), CD15 (P = 0.005), and FLT3-ITD mutation (P = 0.0008) were statistically significant. Using multivariate analysis, the risk factors of venous thrombosis in APL were CD15 (P = 0.043), PAI-1 4G4G (P = 0.009), WT-1 (P = 0.043) and FLT3/ITD (P = 0.013), respectively.

CONCLUSION

Our results suggested the PAI-1 gene 4G4G type, CD15, WT-1 and FLT3-ITD mutations excluding DNMT3A, TET2, IDH1/2, NRAS and ASXL1 are risk factors of thrombotic events in Chinese APL patients.

Trends and outcomes of venous thromboembolism in adult hospitalizations with acute myeloid leukemia: analysis of nationwide inpatient sample from 2010 to 2014

Background: Venous thromboembolism (VTE) occurs frequently in acute myeloid leukemia (AML) patients. There are no population-based studies from the United States (U.S.) analyzing this association. The study aims to analyze the trends, predictors of mortality, and outcomes of VTE in AML patients.Methods: We analyzed the publicly available Nationwide Inpatient Sample (NIS) for years 2010-2014. Hospitalizations due to AML were identified by previously validated International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) codes as the primary diagnosis. VTE was identified by ICD-9-CM codes as secondary diagnosis. Hospitalizations with age less than 18 years of age were excluded. The trends and outcomes were determined using Chi-squared (χ2) test and multivariate regression models.Results: From 2010 to 2014, there were 313,282 hospitalizations with a primary diagnosis of AML and 1,633 hospitalizations (0.1%) had VTE as a concurrent diagnosis. There was a significant increase in the proportion of AML hospitalizations with VTE from 0.47% in 2010 to 0.56% in 2014 (P = 0.014). Multivariable regression analysis showed that the odds of in-hospital mortality were not higher in AML hospitalizations with VTE (odds ratio [OR] 1.11; 95% confidence interval [CI] 0.81-1.52; P = 0.5) than those without VTE. Age group above 84 years carried the highest risk of mortality (OR 3.20; 95% CI 2.77-3.70; P < 0.0001) in AML-VTE patients. Black (OR 1.23; 95% CI 1.13-1.35; P < 0.0001) and uninsured patients (OR 1.50; 95% CI 1.31-1.73; P < 0.0001) were at significantly higher odds of in-hospital mortality amongst the AML-VTE hospitalizations.Conclusion: The proportion of AML hospitalizations with VTE continues to rise in the U.S. After adjusting for confounders, increasing age, Black race, and lack of insurance were found to have higher risk of in-hospital mortality in the AML-VTE cohort. The odds of in-hospital mortality in AML hospitalizations with VTE are not higher than those without VTE.

Advances in the diagnosis and treatment of disseminated intravascular coagulation in haematological malignancies

Haematological malignancies, including acute leukaemia and non-Hodgkin lymphoma, are one of the underlying diseases that frequently cause disseminated intravascular coagulation (DIC), an acquired thrombotic disorder. Concomitant DIC is associated with the severity of the underlying disease and poor prognosis. The Japanese Society on Thrombosis and Hemostasis released the new DIC diagnostic criteria in 2017. This criteria include coagulation markers such as soluble fibrin and the thrombin-antithrombin complex to more accurately evaluate the hypercoagulable state in patients. Among several groups of anticoagulants available, recombinant human soluble thrombomodulin is most frequently used to treat DIC caused by haematological malignancies in Japan. DIC is remitted in parallel with the improvement of the underlying haematological diseases; thus, there is room for debate regarding whether the treatment of DIC would improve the prognosis of patients. Haematopoietic stem cell transplantation as well as the recently introduced chimeric antigen receptor (CAR)-T-cell therapy are innovative therapies to produce a cure in a subset of patients with haematological malignancies. However, coagulopathy frequently occurs after these therapies, which limits the success of the treatment. For example, DIC is noted in approximately 50% of patients after CAT-T-cell therapy in conjunction with cytokine release syndrome. Hematopoietic stem cell transplantation (HSCT) causes endotheliitis, which triggers coagulopathy and the development of potentially lethal complications, such as sinusoidal obstruction syndrome/veno-occlusive disease and transplant-associated thrombotic microangiopathy. This review article describes the pathogenesis, clinical manifestation, diagnosis, and treatment of DIC caused by haematological malignancies, CAR-T-cell therapy, and HSCT.

Prevalence and outcomes of thrombotic and hemorrhagic complications in pediatric acute promyelocytic leukemia in a tertiary Brazilian center

INTRODUCTION

Little attention is given to thrombosis associated with pediatric acute promyelocytic leukemia (APL). This study describes the thrombotic and hemorrhagic manifestations of APL in pediatric patients and evaluates their hemostasis, based on coagulation tests.

METHODS

Inclusion criteria were age 0-18 years and APL diagnosis between April 2005 and November 2017. Patients who had received blood transfusion prior to coagulation tests were excluded. Baseline coagulation tests, hematologic counts, and hemorrhagic/thrombotic manifestations were evaluated.

RESULTS

Median age was 10.7 years (1-15 years). The initial coagulation tests revealed a median Hgb of 8.3 g/dL (4.7-12.9 g/dL), median leucocyte count of 10.9 × 10⁹/L (1.1-95.8 × 10⁹/L), median platelet count of 31.8 × 10⁹/L (2.0-109.0 × 10⁹/L), median activated partial thromboplastin time (aPTT) of 31.7 s (23.0-50.4 s), median aPTT ratio of 1.0 (0.78-1.6), median thromboplastin time (PT) of 17.5 s (13.8-27.7 s), median PT activity of 62% (25-95 %), and median fibrinogen of 157.7 mg/dL (60.0-281.0 mg/dL). Three patients (13%) had thrombosis. At diagnosis, 21 patients (91.3%) had bruising, one patient (4.3%) had splenic vein and artery thrombosis and one patient (4.3%) presented without thrombohemorrhagic manifestations. During treatment, two patients (8.6%) had thrombosis.

CONCLUSION

Knowledge of thrombosis in pediatric APL is important to determine its risk factors and the best way to treat and prevent this complication.

Direct oral anticoagulants in patients with hematologic malignancies

The anticoagulant treatment for patients with hematologic malignancies is low molecular weight heparin (LMWH), which is considered the safest in this particular patients setting. Although direct oral anticoagulants (DOACs) have proven their efficacy and safety in patients with cancer, their use can be challenging in patients with hematologic malignancies due to the peculiarity of these neoplasms: high thrombotic risk, possible onset of thrombocytopenia and concomitant anticancer therapies. The aim of our study was to evaluate the efficacy and safety of DOACs for venous thromboembolism or atrial fibrillation in patients with hematologic malignancies and plasmatic DOACs level during anticancer therapy and at time of bleeding or thrombotic complications. We evaluated patients with hematologic malignancies treated with DOACs for venous thromboembolism or atrial fibrillation-therapy was maintained until the platelet count was ≥50 × 10⁹ /L. In case of concomitant anticancer treatment and haemorrhagic or thrombotic events, we checked DOACs plasma levels (trough and peak). The patients evaluated were 135: 104/135 were on anticancer therapy. We did not observe either thrombotic or major haemorrhagic adverse events. Minor bleedings occurred in 10 patients and clinical relevant non-major (CRNM) in two patients. There was a statistically significant correlation between bleedings and myelodysplastic syndrome. DOACs resulted effective and safe in patients with hematologic malignancies. DOACs plasma level can be helpful in suggesting an early dose adjustment to prevent haemorrhagic adverse event in patients on concomitant anticancer therapy. Larger prospective studies including hematologic patients are warranted to confirm the safety and efficacy of DOACs.

Acute Promyelocytic Leukemia Presenting as Bilateral Acute Limb Ischemia and ST Elevation Myocardial Infarction: A Case Report

Acute myelogenous leukemia (AML) is one of the most common hematologic malignancies. Among them, acute promyelocytic leukemia (APL) is well known for its coagulopathies. Bleeding secondary to disseminated intravascular coagulation, is a common initial presentation and carries a high risk for mortality if left untreated. Thrombotic complications are uncommon and can be related to treatment with chemotherapeutic agents. Large artery thrombosis is very rare, and standardized management remains elusive given the classic revascularization techniques carry a significant risk of re-thrombosis, as well as high risk for mortality given the multiple surgical and percutaneous interventions that are attempted. A multidisciplinary approach is necessary in these cases to carefully weigh the risk and benefits as the classical approach to revascularization and acute arterial thrombosis could potentially cause harm.

Acute promyelocytic leukemia (APL): remaining challenges towards a cure for all

The application of all-trans retinoic acid (ATRA) and arsenic trioxide (ATO) has revolutionized the treatment of acute promyelocytic leukemia (APL). More than 80-90% of patients are expected to be cured with a combination of ATRA, ATO and/or chemotherapy. In this review, we focus on the remaining obstacles to a cure for all patients with APL. We review the issue of early death and coagulopathy and discuss the particular challenges in the care of patients with high-risk APL and patients with relapsed APL. We also give recommendations and highlight ongoing efforts to improve the persistently high early death rate and the outcomes of high risk and relapsed APL patients.

Factors affecting thrombohemorrhagic early death in patients with acute promyelocytic leukemia treated with arsenic trioxide alone

Acute promyelocytic leukemia (APL) is often accompanied by a potentially devastating coagulopathy. Predictors of thrombohemorrhagic early death (TH-ED)/early bleeding death are not well characterized. In this retrospective study, eleven baseline clinical variables that can be assessed easily and promptly were chosen for evaluation in a cohort of 364 patients with APL who were administered arsenic trioxide (ATO) alone as remission induction therapy. TH-ED was defined as death from bleeding or thrombosis within 30 days after hospital admission. Cox proportional hazards regression model was used for both the univariate and multivariate analyses. Totally, 53 patients died from severe bleeding (51 cases) or thrombosis (2 cases), and at 30 days the cumulative incidences of TH-ED were 14.6%. Six independent risk factors for TH-ED were identified, including relapse, male, white blood cell (WBC) count above 10 × 10⁹/L, fibrinogen level below 1 g/L, D-dimer level above 4 mg/L and increased creatinine level. Increased creatinine level was the most powerful risk factor, followed by WBC count > 10 × 10⁹/L. This study identified risk factors for TH-ED in a large cohort of patients with APL, which enriched clinical information on identifying patients at high risk of TH-ED.

Mechanisms and management of coagulopathy in acute promyelocytic leukemia

Acute promyelocytic leukemia (APL) is a subtype of leukemia which is associated with unique and distinctive coagulopathy. In the absence of treatment it is rapidly fatal and even after initiation of therapy the major cause of early mortality is related to hemorrhagic complications. The coagulopathy can be exacerbated with the start of treatment. In the absence of early hemorrhage related deaths the probability of cure exceeds 90% in low and intermediate risk patients and 80% even in high risk patients, highlighting the importance of understanding the pathophysiology of this complication and instituting prompt and appropriate management strategies. The coagulopathy in APL is complex and results from a combination of thrombocytopenia, disseminated intravascular coagulation and hyperfibronlysis. Recently the effect of all-trans retinioc acid (ATRA) induced ETosis on exacerbating coagulopathy in the first few days after starting therapy with this agent raises the potential for potentially novel strategies to reduce the risk of hemorrhage. Currently management is mainly related to rapid initiation of therapy with ATRA along with appropriate and adequate replacement of blood products to correct the coagulopathy. There is limited role for the use of low dose anti-coagulants and anti-fibrinolytic agents in the initial management of this disease. There is limited data on the use of rFVIIa or the use of global tests of hemostasis in the management of this condition.

Arterial thrombosis and cancer

Cancer-associated arterial thrombotic events (ATEs) are increasingly recognized in specific malignancies and in association with the expanding armamentarium of novel chemotherapeutic agents. The improved cancer survival led to cardiovascular complications becoming clinically relevant many years after cancer diagnosis. The pathobiology of ATEs in cancer is complex and the individual patient risk for an ATE entails a multifactorial interaction between the traditional cardiovascular risk factors and comorbidities, the specific malignancy and selected therapy. Treatment with several specific chemotherapeutic agents, immunomodulatory drugs, vascular endothelial growth factor pathway inhibitors, tyrosine kinase inhibitors, and radiotherapy, impart increased risk for ATEs that result from specific therapy-related mechanisms, often involving endothelial injury. Cancer cell-specific prothrombotic properties are important players in the pathogenesis of cancer-associated hypercoagulability. There are distinct biological and molecular processes preferentially activated in specific cancer cells which can trigger ATEs, including platelet activation, increased expression of procoagulants and suppression of fibrinolytic activity. ATEs portend adverse prognosis in cancer patients. Prevention and treatment of cancer-associated ATEs may be improved by greater awareness and careful monitoring for vascular toxicity, aggressive effort to optimize conventional cardiovascular risk factors, and use of antiplatelet and antithrombotic agents in selected patients. These issues are targets for future studies aimed to reduce ATEs in patients with cancer.

Venous thromboembolism incidence in hematologic malignancies

Venous thromboembolism (VTE) remains a major cause of morbidity and mortality in patients with cancer. Although some very well validated scores delineate the risk of VTE by cancer subtype and other risk factors, hematologic malignancies are underrepresented in these models. This subgroup represents a unique entity that undergoes therapy that can be thrombogenic. The overall risk of VTE in patients with leukemia depends on the use of L-asparaginase treatment, older age, comorbidities and central venous catheters. Patients with acute promyelocytic leukemia are at particularly high risk of VTE but also have an increased risk of bleeding. Patients with aggressive lymphomas have a high incidence of VTE, roughly 10%. Patients with multiple myeloma at highest risk of VTE are those receiving immunomodulatory agents such as thalidomide or lenalidomide. Allogeneic stem cell transplantation carries a risk of thrombosis, particularly in patients developing graft versus host disease. This review summarizes the incidence of VTE in leukemia, lymphoma, myeloma and stem cell transplantation and provides practical guidance for preventing and managing VTE in patients with hematologic malignancies.

Incidence of venous thromboembolism and use of anticoagulation in hematological malignancies: Critical review of the literature

Venous Thromboembolism (VTE) frequently complicates the course of hematologic malignancies (HM) and its incidence is similar to that observed in high-risk solid tumors. Despite that, pharmacologic prophylaxis and treatment of VTE in patients with HM is challenging, mainly because a severe thrombocytopenia frequently complicates the course of treatments or may be present since diagnosis, thus increasing the risk of bleeding. Therefore, in this setting, safe and effective methods of VTE prophylaxis and treatment have not been well defined and hematologists generally refer to guidelines produced for cancer patients that give indications on anticoagulation in patients with thrombocytopenia. In this review, besides to summarize the incidence and the available data on prophylaxis and treatment of VTE in HM, we give some advices on how to use antithrombotic drugs in patients with HM according to platelets count.

Laboratory biomarkers for venous thromboembolism risk in patients with hematologic malignancies: A review

INTRODUCTION

Despite high rates of venous thromboembolism (VTE) among patients with hematologic malignancies, few tools exist to assist providers in identifying those patients at highest risk for this potentially fatal complication. Laboratory biomarkers, such as d-dimer, have demonstrated utility in some clinical settings to distinguish patients at increased risk.

MATERIALS AND METHODS

We performed a systematic review of the literature utilizing search terms including "biomarker", "venous thromboembolism", "hematologic malignancy", "lymphoma", "myeloma" and "leukemia" in the Medline database. A total of 25 studies investigating laboratory biomarkers of increased thrombotic risk in the setting of hematologic malignancy were identified and included in this review.

RESULTS AND CONCLUSIONS

The most studied biomarkers, d-dimer and fibrinogen, demonstrated some degree of efficacy in identifying high-risk patients at levels >4.0 mg/L or <1.0 g/L respectively. Additional markers which demonstrated promise included thrombin generation, mean platelet volume, soluble VEGF, soluble P-selectin and extracellular vesicles. Other biomarkers reviewed, which did not consistently demonstrate significant associations with VTE included prothrombin fragments F1 + 2, factor VIII, protein C, protein S, von Willebrand antigen and activity, antithrombin, thrombin antithrombin complex, antiphospholopid antibody, plasminogen activator inhibitor, tissue factor pathway inhibitor and several variants associated with known hypercoagulable states (factor V Leiden, prothrombin gene variant, methylenetetrahydrofolate reductase variant). Data to support any of the biomarkers discussed here in routine clinical decision-making are currently lacking, but additional investigation in clinical studies, ideally in combination with clinical factors known to be associated with increased thrombotic risk, is warranted.

Thrombosis in adult patients with acute leukemia

PURPOSE OF REVIEW

Recent studies indicate that the risk of thrombosis in hematologic patients may be similar or even higher than that found in patients with solid tumors. However, available information about pathogenesis and incidence of thrombosis in acute leukemia is limited. This review focuses on mechanisms underlying thrombosis in acute leukemia and discusses recent literature data.

RECENT FINDINGS

In the last few years, proofs have been provided that leukemic cells release free prothrombotic products, such as micro-vesicles, tissue factors, circulating free DNA and RNA. Furthermore, leukemic blasts can activate the procoagulant population of platelets, which initiate and amplify coagulation, causing thrombosis. In addition to factors produced by acute leukemia itself, others concur to trigger thrombosis. Some drugs, infections and insertion of central venous catheter have been described to increase risk of thrombosis in patients with acute leukemia.

SUMMARY

Thrombosis represents a serious complication in patients affected by myeloid and lymphoid acute leukemia. A proper knowledge of its pathophysiology and of the predisposing risk factors may allow to implement strategies of prevention. Improving prevention of thrombosis appears a major goal in patients whose frequent conditions of thrombocytopenia impede an adequate delivery of anticoagulant therapy.

Complications and management of coagulation disorders in leukemia patients

Patients with leukemia are predisposed to various coagulation abnormalities. Thrombosis and bleeding continue to be a major cause of morbidity and mortality in leukemias. The pathophysiology of these disorders is unique, and not only the disease but also the treatment and other factors play a role. There has been an increase in the understanding of these disorders in leukemias. However, it is still difficult to predict when and which patients will have these complications. The evidence for the management of coagulation abnormalities in leukemias is still evolving and not as established as in solid malignancies. The management of these disorders is complex, and making clinical decisions is often challenging. In the era of specialization, where there are different hematologists looking after benign- and malignant-hematology patients, opinions of thrombosis experts are often sought by leukemia specialists. This review aims to bridge the gap in the knowledge of these disorders between these specialists.

Recent advances in acute promyelocytic leukaemia

Acute promyelocytic leukaemia (APML) is a subtype of leukaemia arising from a distinct reciprocal translocation involving chromosomes 15 and 17, which results in the PML-RARA fusion gene. Over the past three decades, APML has been transformed from a highly fatal disease to a highly curable one. This drastic improvement is because of the introduction of a new treatment strategy with all-trans retinoic acid and, more recently, arsenic trioxide. The revolutionary treatment of APML has also paved the way for a new cancer treatment, which is genetically targeted therapy. In this review, we look into this amazing journey of transformation and provide recent advances in the management of APML.

Leukemia and Risk of Venous Thromboembolism: A Meta-analysis and Systematic Review of 144 Studies Comprising 162,126 Patients

Venous thromboembolism (VTE) has significant clinical implications in leukemia patients. However, the actual frequency of this complication remains unknown. We performed a systematic review and meta-analysis to better estimate the frequency of this complication and to assess the risk factors that contribute to its occurrence. We searched several databases, including PubMed, Embase, and Web of Science, and assessed study quality using the Newcastle–Ottawa scale. The pooled frequency of VTE in leukemia patients was calculated. A total of 144 studies met the eligibility criteria. The incidence rate (IR) of VTE from 72 prospective studies comprising 9,061 patients was 5% (95%CI: 4–6%). The incidence rate (IR) of VTE in ALL, CLL, total-AML, and CML population was 5% (95%CI: 4–6%), 3% (95%CI: 2–5%), 6% (95%CI: 4–8%) and 13% (95%CI: 1–36%). The incidence of VTE was markedly decreased among ALL patients who received anticoagulation treatment (IR: 1%, 95%CI: 0–6%) or concentrates therapy (IR: 3%, 95%CI: 0–9%). The overall incidence of VTE in the leukemia population was high, particularly in transplant recipients, who had the highest risk (IR: 8%, 95% CI: 4–13%). Prophylactic approaches could significantly decrease the occurrence of VTE events.

Epileptic Seizure, Postictal Hemiparesis, and Hyperleukocytosis

Introduction: Acute ischemic stroke (AIS) is a rare event in infancy. Besides vasculopathy, thrombophilia, or cardiac disorders, cancer and chemotherapy are known predisposing factors for AIS. Leukemia can be associated with different abnormal coagulation parameters, but severe bleeding or thrombosis occurs rarely. Clinical Course: We report the case of a 2-year-old boy who was presented to our emergency ward after a prolonged seizure with right sided postictal hemiparesis. Cranial computed tomography scan revealed a large infarction and edema due to thrombosis of the left carotid artery, the middle cerebral artery, and the anterior cerebral artery. Laboratory workup showed 196 g/L leukocytes with 75% myeloid blast cells. Immediate exchange transfusion, hydration, and chemotherapy with cytarabine were started. During the hospital course intracranial pressure increased and the patient developed a unilateral dilated pupil unresponsive to light. Cranial computed tomography scan revealed a new infarction in the right middle cerebral artery territory. Refractory increased intracranial pressure and brain stem herniation developed, and the child died 3 days after admission to hospital. Conclusion: Seizures with postictal hemiparesis due to cerebral infarction can be a rare manifestation of acute myeloid leukemia. Leukocytosis and cancer-induced coagulopathy are main reasons for thrombosis and/or hemorrhage. High leukocyte counts need immediate interventions with hydration, careful chemotherapy, and perhaps exchange transfusion or leukapharesis. In the presence of thrombosis, anticoagulation must be discussed despite the risk of bleeding due to hyperfibrinolysis and low platelet counts. Mortality may be reduced by awareness of this rare presentation of leukemia and prompt institution of leucoreductive treatment.

Severe Lower Limb Ischemia by Massive Arterial Thrombosis Revealing an Acute Myeloid Leukemia Needing for Leg Amputation: Clinical and Emotional Aspects Related to the Communication with the Patient and His Family

Large vessel thrombosis is a very rare clinical presentation of acute leukemia, generally associated with coagulopathy, usually characteristic of acute promyelocytic leukemia. A 13- year-old boy with a previously undiagnosed acute myeloid leukemia was referred to our hospital with acute ischemia of the right lower limb due to occlusion of the right external iliac artery, treated with emergency double surgical thromboembolectomy and chemotherapy. The thrombotic complication resulted in leg amputation. Now the boy is well in complete remission, with a good social integration and quality of life, 30 months after completing treatment. The report highlights the crucial role of early diagnosis and subsequent chemotherapy in avoiding amputation. We particularly focused critical and emotional aspects related to the communication about the leg amputation with the patient and his family.

Recurrent Arterial Thrombosis as a Presenting Feature of a Variant M3-Acute Promyelocytic Leukemia

Acute limb ischemia (ALI) is a common vascular emergency. Hematologic malignancies are commonly associated with derangement of normal hemostasis and thrombo-hemorrhagic symptoms during the course of the disease are common. However, ALI as an initial presenting feature of acute leukemia is rare. Due to the rarity of this presentation, there is a scarcity of prospective randomized data to optimally guide the management of these patients. Current knowledge is mainly based on isolated cases. We report our experience managing a patient who presented with ALI and was found to have occult leukemia. A review of all cases with ALI as a presenting feature of acute leukemia is also presented.

Massive Pulmonary Embolism at the Onset of Acute Promyelocytic Leukemia

Life-threatening bleeding is a major and early complication of acute promyelocytic leukemia (APL), but in the last years there is a growing evidence of thromboses in APL. We report the first case of a young woman with dyspnea as the first symptom of APL due to massive pulmonary embolism (PE) successfully treated with thrombolysis for PE and heparin. APL has been processed with a combination of all-trans retinoic acid (ATRA) and arsenic trioxide (ATO) obtaining complete remission.

Thromboembolic risk in hematological malignancies

There are a growing number of studies documenting that, similarly to patients with solid cancers, also patients with hematological malignancies (i.e., acute leukemia, lymphoproliferative and myeloproliferative neoplasms and plasma cell disorders) are at increased risk of thrombosis. The pathogenesis of the hypercoagulable state associated with hematological cancers is often multifactorial. Contributor factors include tumor cell-derived procoagulants, antineoplastic therapies, central venous catheters, concomitant infections and advanced age. In this narrative review, the epidemiology, pathogenesis and management of thrombosis in patients with hematological malignancies are reviewed.

Transient ischemic attack as an unusual initial manifestation of acute promyelocytic leukemia

Patients with acute promyelocytic leukemia (APL) are prone to both bleeding and thrombosis. Both of these have a significant impact on the morbidity and mortality of patients with this disease. Here we report a case of a 41-year-old male, who presented with transient ischemic attack (TIA) and early neurological deterioration (END) as initial manifestations prior to an ultimate diagnosis of APL. This patient had no cerebrovascular risk factors or familial cerebrovascular disease. The patient experienced an acute ischemic stroke, verified by magnetic resonance imaging (MRI), in less than 24 h after his second hospital admission. Some APL patients suffer from cerebral ischemia as an initial manifestation or during induction therapy, and patients presenting this condition may continue to deteriorate until their death during hospitalization. Thus, APL should be considered as a possible underlying disease in patients with TIA without cerebrovascular risk factors. Delayed diagnosis and treatment of APL can be fatal.

A Rare Occurrence of Simultaneous Venous and Arterial Thromboembolic Events - Lower Limb Deep Venous Thrombosis and Pulmonary Thromboembolism as Initial Presentation in Acute Promyelocytic Leukemia

The development of acute myeloid leukemia has been attributed to various factors, including hereditary, radiation, drugs, and certain occupational exposures. The association between malignancy and venous thromboembolism events is well established. Here, we present a case of a 70-year-old Indian man who had presented with arterial and venous thrombosis, and the patient was later diagnosed with acute promyelocytic leukemia (APL). In our case, the patient presented with right lower limb deep venous thrombosis and pulmonary thromboembolism four months prior to the diagnosis of APL. Although thromboembolic event subsequent to the diagnosis of malignancy, and especially during the chemotherapy has been widely reported, this prior presentation with simultaneous occurrence of both venous and arterial thromboembolism has rarely been reported. We take this opportunity to state the significance of a complete medical evaluation in cases of recurrent or unusual thrombotic events.

Acute Coronary Syndrome Manifesting as an Adverse Effect of All-trans-Retinoic Acid in Acute Promyelocytic Leukemia: A Case Report with Review of the Literature and a Spotlight on Management

Background. Acute promyelocytic leukemia is characterized by t(15;17). This leads to the formation of PML/RARα which blocks the differentiation of blasts at the stage of promyelocytes. This is reversed by all-trans-retinoic acid (ATRA), a vitamin A derivative. Acute myocardial ischemia is a rare side effect of ATRA. Case Report. We report a case of acute coronary syndrome manifesting as an adverse effect of ATRA in a lady with APL who had no other risk factors for cardiovascular disease. Conclusions. We emphasize the need for high index of suspicion for the diagnosis of this entity. In the light of this case, the rare instances of ATRA associated acute myocardial ischemia recorded in the literature and the options available for treatment of acute promyelocytic leukemia sans ATRA have been reviewed.

Acute promyelocytic leukemia presenting as pulmonary thromboembolism: Not all APLs bleed

We present a rare case of acute promyelocytic leukemia (APL) presenting as pulmonary thromboembolism being misdiagnosed as community-acquired pneumonia. Thrombotic phenomenon in APL are poorly understood and grossly underreported. In our case, following no response to standard antibiotic treatment, the patient was further investigated and detected to have an acute pulmonary thromboembolism following right lower limb deep vein thrombosis (DVT). Though, complete blood picture revealed only mild hyperleukocytosis, bone marrow biopsy and aspiration revealed 60% blasts and a positive t (15,17)(q22,12) and PML retinoic acid receptor alpha (RARA) fusion protein on molecular cytogenetics. He was diagnosed as APL and received treatment with all-transretinoic acid (ATRA) and arsenic trioxide (ATO) and therapeutic anticoagulation

Thrombo-hemorrhagic deaths in acute promyelocytic leukemia

Acute promyelocytic leukemia (APL) has become the most curable form of acute myeloid leukemia after the advent of all-trans retinoic acid (ATRA). However, early deaths (ED) mostly due to the disease-associated coagulopathy remain the major cause of treatment failure. In particular, hemorrhagic events account for 40-65% of ED and several prognostic factors have been identified for such hemorrhagic deaths, including poor performance status, high white blood cell (WBC) count and coagulopathy. Occurrence of thrombosis during treatment with ATRA may be associated with differentiation syndrome (DS) or represent an isolated event. Some prognostic factors have been reported to be associated with thrombosis, including increased WBC or aberrant immunophenotype of leukemic promyelocytes. Aim of this review is to report the incidence, severity, possible pathogenesis and clinical manifestations of thrombo-haemorrhagic deaths in APL.

Thrombotic events in acute promyelocytic leukemia

INTRODUCTION

Thrombotic events (TE) appear to be more common in acute promyelocytic leukemia (APL) than in other acute leukemias, with reported prevalence ranging from 2 to 10-15%.

MATERIALS AND METHODS

We retrospectively analyzed the data on TE appearance in 63 APL patients.

RESULTS

TE occured in 13 (20.6%) cases, four arterial (6.3%) and nine venous (14.3%). TE were more frequently diagnosed after initiation of weekly D-dimer monitoring (7 TE during 20 months vs 6 during 76 months, P=0.032). Patients with and without venous thrombosis were significantly different regarding female/male ratio (P=0.046), PT (P=0.022), aPTT (P=0.044), ISTH DIC score (P=0.001), bcr3 (P=0.02) and FLT3-ITD (P=0.028) mutation. The most significant risk factor for venous TE occurrence in multivariate analysis was FLT3-ITD mutation (P=0.034). PAI-1 4G/4G polymorphism was five times more frequent in patients with venous TE than without it (P=0.05). Regarding risk factors for arterial TE we failed to identify any.

CONCLUSIONS

We have demonstrated that APL-related TE rate is higher than previously reported and that weekly D-dimer monitoring might help to identify patients with silent thrombosis. Moreover, our study suggests a possible relationship between venous TE occurrence and several laboratory findings (PT, aPTT, ISTH DIC score, bcr3 isoform, FLT3-ITD mutation and PAI 4G/4G). Prophylactic use of heparin might be considered in patients with ISTH DIC score<5, bcr3 isoform, FLT3-ITD mutation and PAI 4G/4G.