Analysis of anticoagulation strategies for venous thromboembolism during severe thrombocytopenia in patients with hematologic malignancies: a retrospective cohort

[Translation into French and republication of: "Management of cancer-associated thromboembolism in vulnerable population"]

Although all patients with cancer-associated thrombosis (CAT) have a high morbidity and mortality risk, certain groups of patients are particularly vulnerable. This may expose the patient to an increased risk of thrombotic recurrence or bleeding (or both), as the benefit-risk ratio of anticoagulant treatment may be modified. Treatment thus needs to be chosen with care. Such vulnerable groups include older patients, patients with renal impairment or thrombocytopenia, and underweight and obese patients. However, these patient groups are poorly represented in clinical trials, limiting the available data on which treatment decisions can be based. Meta-analysis of data from randomised clinical trials suggests that the relative treatment effect of direct oral factor Xa inhibitors (DXIs) and low molecular weight heparin (LMWH) with respect to major bleeding could be affected by advanced age. No evidence was obtained for a change in the relative risk-benefit profile of DXIs compared to LMWH in patients with renal impairment or of low body weight. The available, albeit limited, data do not support restricting the use of DXIs in patients with TAC on the basis of renal impairment or low body weight. In older patients, age is not itself a critical factor for choice of treatment, but frailty is such a factor. Patients over 70 years of age with CAT should undergo a systematic frailty evaluation before choosing treatment and modifiable bleeding risk factors should be addressed. In patients with renal impairment, creatine clearance should be assessed and monitored regularly thereafter. In patients with an eGFR less than 30mL/min/1.72m2, the anticoagulant treatment may need to be adapted. Similarly, platelet count should be assessed prior to treatment and monitored regularly. In patients with grade 3-4, thrombocytopenia (less than 50,000platelets/μL) treatment with a LMWH at a reduced dose should be considered. For patients with CAT and low body weight, standard anticoagulant treatment recommendations are appropriate, whereas in obese patients, apixaban may be preferred.

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.

Anticoagulation in cancer patients with atrial fibrillation and grade 3-4 thrombocytopenia

INTRODUCTION

Atrial fibrillation or flutter (AF) is prevalent in cancer patients. Many of these patients have an indication for anticoagulation (AC) but are also at risk for developing chemotherapy-induced thrombocytopenia. There are scarce data regarding management of AC and risk of bleeding and thrombosis in cancer patients with AF and thrombocytopenia.

AIM

To assess anticoagulation management and incidence of bleeding and arterial thromboembolism (ATE) in cancer patients with AF and grade 3-4 thrombocytopenia (platelets <50 × 109/L).

METHODS

A retrospective cohort study included adults with active cancer, grade 3-4 thrombocytopenia and AF with CHA2DS2-VASc score ≥ 1. Patients were stratified according to AC discontinuation (No-AC) or continuation (Continue-AC) when platelets dropped below 50 × 109/L and followed for 30 days. The study outcomes were ATE (ischemic stroke, transient ischemic attack or systemic emboli) and major bleeding. Cox proportional hazards model was used to calculate hazard ratios (HR) with death as a competing risk (Fine and Gray model).

RESULTS

The cohort included 131 patients; 90 in the No-AC group and 41 in the Continue-AC group. Patient characteristics were balanced between the groups. The 30-day cumulative incidence of ATE was 2 % [95 % CI 0.4 %-7 %] in the No-AC group and 2 % [0.2 %-11 %] in the Continue-AC group (HR 0.92 [95 % CI 0.09-9.88]). The 30-day cumulative incidence of major bleeding was 7.8 % [95 % CI 3.40 %-14.52 %] and 2.44 % [95 % CI 0.18 %-11.22 %] in the No-AC and Continue-AC groups, respectively (HR 3.29 [95 % CI 0.42-26.04]).

CONCLUSIONS

The high rate of bleeding and low rate of ATE in thrombocytopenic cancer patients with AF suggests that holding AC during time-limited periods may be a reasonable approach.

Management of cancer-associated thromboembolism in vulnerable population

Although all patients with cancer-associated thrombosis (CAT) have a high morbidity and mortality risk, certain groups of patients are particularly vulnerable. This may expose the patient to an increased risk of thrombotic recurrence or bleeding (or both), as the benefit-risk ratio of anticoagulant treatment may be modified. Treatment thus needs to be chosen with care. Such vulnerable groups include older patients, patients with renal impairment or thrombocytopenia, and underweight and obese patients. However, these patient groups are poorly represented in clinical trials, limiting the available data, on which treatment decisions can be based. Meta-analysis of data from randomised clinical trials suggests that the relative treatment effect of direct oral factor Xa inhibitors (DXIs) and low molecular weight heparin (LMWH) with respect to major bleeding could be affected by advanced age. No evidence was obtained for a change in the relative risk-benefit profile of DXIs compared to LMWH in patients with renal impairment or of low body weight. The available, albeit limited, data do not support restricting the use of DXIs in patients with CAT on the basis of renal impairment or low body weight. In older patients, age is not itself a critical factor for choice of treatment, but frailty is such a factor. Patients over 70 years of age with CAT should undergo a systematic frailty evaluation before choosing treatment and modifiable bleeding risk factors should be addressed. In patients with renal impairment, creatine clearance should be assessed and monitored regularly thereafter. In patients with an eGFR<30mL/min/1.72m2, the anticoagulant treatment may need to be adapted. Similarly, platelet count should be assessed prior to treatment and monitored regularly. In patients with grade 3-4, thrombocytopenia (<50,000 platelets/μL) treatment with a LMWH at a reduced dose should be considered. For patients with CAT and low body weight, standard anticoagulant treatment recommendations are appropriate, whereas in obese patients, apixaban may be preferred.

Anticoagulation management and related outcomes in patients with cancer-associated thrombosis and thrombocytopenia: A systematic review and meta-analysis

BACKGROUND

Patients with cancer have an increased risk of both venous thromboembolism (VTE) requiring anticoagulation and thrombocytopenia. The optimal management is unclear. We performed a systematic review and meta-analysis to evaluate the outcomes in these patients.

METHODS

We searched MEDLINE, Embase, Scopus, and Cochrane Central Register of Controlled Trials from inception to February 5, 2022. Studies assessing adult patients with cancer-associated thrombosis and platelet count <100 × 10⁹/L were included. Three anticoagulation management strategies were reported: full dose, modified dose, or no anticoagulation. The primary efficacy outcome was recurrent VTE, and the primary safety outcome was major bleeding. The incidence rates of thrombotic and bleeding outcomes by anticoagulation management strategies were descriptive, and were pooled using random effects model and expressed as events per 100 patient-months with associated 95 % confidence intervals (CI).

RESULTS

We included 19 observational cohort studies (N = 1728 patients) in the systematic review, with 10 included in the meta-analysis (N = 707 patients). Approximately 90 % of patients had hematological malignancies, with low-molecular-weight heparin being the main anticoagulant. The rates of recurrent VTE and bleeding complications were high regardless of management strategies - recurrent VTE on full dose: 2.65/100 patient-months (95 % CI 1.62-4.32), modified dose: 3.51/100 patient-months (95 % CI 1.00-12.39); major bleeding on full dose: 4.45/100 patient-months (95 % CI 2.80-7.06), modified dose: 4.16/100 patient-months (95 % CI 2.24-7.74). There was serious risk of bias in all studies.

CONCLUSIONS

Patients with cancer-associated thrombosis and thrombocytopenia have high risks of both recurrent VTE and major bleeding, but current literature is significantly limited to guide the best management.

Early-onset venous thromboembolisms in newly diagnosed non-promyelocytic acute myeloid leukemia patients undergoing intensive induction chemotherapy

OBJECTIVES AND METHODS

Venous thromboembolic (VTE) events are emerging as frequent complications in acute myeloid leukemia (AML); however, there is insufficient data regarding epidemiology, risk factors, and impact on outcomes. The optimal approach to balance risks of thrombosis and hemorrhage remains unclear. This retrospective single-center study in AML patients undergoing induction chemotherapy between 2007 and 2018 assessed incidence, risk factors, features, and outcomes of early-onset VTE.

RESULTS

423 patients (median age 59 years) were enrolled. VTE was diagnosed in 31 patients (7.3%) within 3 months of admission. The median time to VTE was 3 days. Non-central venous catheter (CVC)-related VTE occurred in 19 patients (61%). Main risk factor for VTE was leukocytosis at admission, independent of platelet counts/INR. Four patients (13%) exhibited VTE recurrence. No deaths directly related to VTE or major bleeding events associated with platelet-adjusted anticoagulation in patients with VTE were recorded. There was no clear impact of VTE on 1-year overall survival; however, non-CVC-related VTE may be associated with adverse outcomes.

CONCLUSIONS

Early-onset VTE is a common complication in newly diagnosed AML patients admitted for induction chemotherapy. Leukocytosis is an independent VTE risk factor. The potentially adverse impact of non-CVC-related VTE merits further study.

Platelet transfusion and anticoagulation in hematological cancer-associated thrombosis and thrombocytopenia: The CAVEaT multicenter prospective cohort

BACKGROUND

Venous thromboembolism (VTE) in patients with thrombocytopenia represents a complex management challenge.

OBJECTIVES

To describe practice, document outcomes, and compare management to national guidelines.

METHODS

We present a prospective multicenter cohort of 105 patients with hematological cancer, VTE within 28 days, and platelets <50 × 109 /L from May 14, 2019 to April 24, 2021 from 20 sites.

RESULTS

Median age was 64 and median initial platelet count 28 × 109 /L. Thromboses were: 46% catheter-associated, 11% lower limb, 33% pulmonary emboli (PE), and 10% other sites. Management was according to International Society on Thrombosis and Haemostasis (ISTH) guidance in 30 (47%) of 64 patients with high-risk thrombosis and 2 (5%) of low-risk thrombosis (catheter-associated or asymptomatic subsegmental PE). Twelve patients (11%) received no anticoagulation. At 28 days mortality was 15%, 8% experienced VTE progression, 7% experienced major bleeding, and 25% experienced clinically relevant non-major bleeding. Four inferior vena cava filters were placed, two were later removed. The median number of platelet units transfused was 5 (range 0-53). Twenty-seven percent of patients had a change of management strategy by 28 days. There was no clear relationship among platelet transfusion threshold, anticoagulant dose reduction threshold, and risk of thrombosis progression or major bleeding.

CONCLUSIONS

This data set demonstrates the heterogeneity of approaches used in patients presenting with severe thrombocytopenia and acute thrombosis and confirms the high rates of bleeding in this cohort with thrombosis progression rates similar to the wider cancer-associated thrombosis population. Randomized data is required to inform the optimal management.

Characteristics and predictors of venous thrombosis recurrence in patients with cancer and catheter-related thrombosis

Background

Central venous catheters raise the risk of catheter-related thrombosis (CRT) in patients with cancer, typically affecting the upper extremity. Management of CRT involves catheter removal and anticoagulation. However, robust evidence is lacking on the optimal timing of anticoagulation relative to catheter removal.

Objectives

Our goal is to provide a better understanding of the factors that increase the risk of recurrent venous thromboembolism (VTE) in these patients.

Patients and Methods

We conducted a retrospective chart review of all consecutive patients with cancer in our hospital affected by CRT between January 1, 2015, and December 31, 2017. We measured recurrence of VTE as thrombosis in any vascular bed or pulmonary embolism, for up to 2 years after diagnosis. Logistic and competing risk regression analyses were used to determine the association between different clinical factors and any VTE recurrence in patients with cancer and CRT.

Results

Of the 257 individuals meeting the inclusion criteria, 80.2% had their catheter removed; of these, 50.5% did not receive anticoagulation before the removal. Patients who did not receive anticoagulation before the removal had increased 3-month and 1-year risks of recurrent VTE (odds ratio, 5.07 [95% confidence interval [CI], 1.53-23.18]; and hazard ratio, 3.47 [95% CI, 1.34-9.01]), respectively.

Conclusions

Our study supports the use of anticoagulants before catheter removal in patients with CRT. Randomized clinical trials are recommended to establish stronger evidence pertaining to the long-term risk of VTE recurrence and the effect of catheter reinsertion.

EHA Guidelines on Management of Antithrombotic Treatments in Thrombocytopenic Patients With Cancer

In cancer patients, thrombocytopenia can result from bone marrow infiltration or from anticancer medications and represents an important limitation for the use of antithrombotic treatments, including anticoagulant, antiplatelet, and fibrinolytic agents. These drugs are often required for prevention or treatment of cancer-associated thrombosis or for cardioembolic prevention in atrial fibrillation in an increasingly older cancer population. Data indicate that cancer remains an independent risk factor for thrombosis even in case of thrombocytopenia, since mild-to-moderate thrombocytopenia does not protect against arterial or venous thrombosis. In addition, cancer patients are at increased risk of antithrombotic drug-associated bleeding, further complicated by thrombocytopenia and acquired hemostatic defects. Furthermore, some anticancer treatments are associated with increased thrombotic risk and may generate interactions affecting the effectiveness or safety of antithrombotic drugs. In this complex scenario, the European Hematology Association in collaboration with the European Society of Cardiology has produced this scientific document to provide a clinical practice guideline to help clinicians in the management of patients with cancer and thrombocytopenia. The Guidelines focus on adult patients with active cancer and a clear indication for anticoagulation, single or dual antiplatelet therapy, their combination, or reperfusion therapy, who have concurrent thrombocytopenia because of either malignancy or anticancer medications. The level of evidence and the strength of the recommendations were discussed according to a Delphi procedure and graded according to the Oxford Centre for Evidence-Based Medicine.

Management of cancer-associated thrombosis with thrombocytopenia: Impact of the ISTH guidance statement

Background

Optimal management of cancer-associated thrombosis (CAT) in patients with thrombocytopenia remains difficult given competing risks of recurrent thrombosis and increased bleeding. We determine the impact of the ISTH Scientific and Standardization Committee (SCC) guidance on CAT management and thrombocytopenia on platelet transfusion, bleeding, and recurrent thrombosis.

Methods

A retrospective review was performed of patients with CAT and thrombocytopenia who required anticoagulation for VTE for 11 months before and after implementation of the ISTH SCC guidance. Medical records were reviewed to identify the type of VTE event, number of platelet transfusions, incidence of bleeding, and VTE recurrence within pre- and postintervention time periods.

Results

A total of 41 and 80 cases were included in the preintervention and postintervention periods, respectively. The preintervention group showed a trend toward less acute VTE events (39% vs 55%; P = .05). The postintervention period had an increased per-patient platelet transfusion (median, 2.5 vs 4; P = .05). Nonmajor bleeding was increased in the postintervention group (2% vs 16%; P = 0.03) and included all six (8%) major hemorrhages (P = .09). There was numerically less recurrent thrombosis in the postintervention group (20% vs 8%; P = .07), which was not significantly different when accounting for acuity of VTE. Management adherence was strong, at 91%, in the postintervention group.

Conclusion

The ISTH guidance on management of cancer-associated thrombosis in patients with thrombocytopenia was successfully implemented in an academic medical center. There was no significant difference in bleeding or recurrent thrombosis outcomes after adjusting for acuity of VTE.

Current management of cancer-associated venous thromboembolism in patients with thrombocytopenia: a retrospective cohort study

Optimal management of venous thromboembolism (VTE) in cancer patients with thrombocytopenia is uncertain. We described current management and clinical outcomes of these patients. We retrospectively included a cohort of cancer patients with acute VTE and concomitant mild (platelet count 100,000-150,000/mm³), moderate (50,000-99,000/mm³), or severe thrombocytopenia (< 50,000/mm³). Univariate and multivariate logistic regression analyses explored the association between different therapeutic strategies and thrombocytopenia. The incidence of VTE and bleeding complications was collected at a 3-month follow-up. A total of 194 patients of whom 122 (62.89%) had mild, 51 (26.29%) moderate, and 22 (11.34%) severe thrombocytopenia were involved. At VTE diagnosis, a full therapeutic dose of LMWH was administered in 79.3, 62.8 and 4.6% of patients, respectively. Moderate (OR 0.30; 95% CI 0.12-0.75), severe thrombocytopenia (OR 0.01; 95% CI 0.00-0.08), and the presence of cerebral metastasis (OR 0.06; 95% CI 0.01-0.30) were independently associated with the prescription of subtherapeutic LMWH doses. Symptomatic VTE (OR 4.46; 95% CI 1.85-10.80) and pulmonary embolism (OR 2.76; 95% CI 1.09-6.94) were associated with the prescription of full therapeutic LMWH doses. Three-month incidence of VTE was 3.9% (95% CI 1.3-10.1), 8.5% (95% CI 2.8-21.3), 0% (95% CI 0.0-20.0) in patients with mild, moderate, and severe thrombocytopenia, respectively. The corresponding values for major bleeding and mortality were 1.9% (95% CI 0.3-7.4), 6.4% (95% CI 1.7-18.6), 0% (95% CI 0.0-20.0) and 9.6% (95% CI 5.0-17.4), 48.2% (95% CI 16.1-42.9), 20% (95% CI 6.6-44.3). In the absence of sound evidence, anticoagulation strategy of VTE in cancer patients with thrombocytopenia was tailored on an individual basis, taking into account not only the platelet count but also VTE presentation and the presence of cerebral metastasis.

Anticoagulation in cancer-associated thromboembolism with thrombocytopenia: a prospective, multi-center cohort study

In patients with cancer with VTE and thrombocytopenia, modified-dose anticoagulation was associated with a lower rate of major hemorrhage.

In this cohort, recurrent VTE was not observed after initiation of modified-dose anticoagulation.

Venous thromboembolism (VTE) with concurrent thrombocytopenia is frequently encountered in patients with cancer. Therapeutic anticoagulation in the setting of thrombocytopenia is associated with a high risk of hemorrhage. Retrospective analyses suggest the utility of modified-dose anticoagulation in this population. To assess the incidence of hemorrhage or thrombosis according to anticoagulation strategy, we performed a prospective, multicenter, observational study. Patients with active malignancy, acute VTE, and concurrent thrombocytopenia (platelet count <100 000/µL) were enrolled. The cumulative incidences of hemorrhage or recurrent VTE were determined considering death as a competing risk. Primary outcomes were centrally adjudicated and comparisons made according to initial treatment with full-dose or modified-dose anticoagulation. A total of 121 patients were enrolled at 6 hospitals. Seventy-five patients were initially treated with full-dose anticoagulation (62%) and 33 (27%) with modified-dose anticoagulation; 13 (11%) patients received no anticoagulation. Most patients who received modified-dose anticoagulation had a hematologic malignancy (31 of 33 [94%]) and an acute deep vein thrombosis (28 of 33 [85%]). In patients who initially received full-dose anticoagulation, the cumulative incidence of major hemorrhage at 60 days was 12.8% (95% confidence interval [CI], 4.9-20.8) and 6.6% (95% CI, 2.4-15.7) in those who received modified-dose anticoagulation (Fine-Gray hazard ratio, 2.18; 95% CI, 1.21-3.93). The cumulative incidence of recurrent VTE at 60 days in patients who initially received full-dose anticoagulation was 5.6% (95% CI, 0.2-11) and 0% in patients who received modified-dose anticoagulation. In conclusion, modified-dose anticoagulation appears to be a safe alternative to therapeutic anticoagulation in patients with cancer who develop deep vein thrombosis in the setting of thrombocytopenia.

Impact of anticoagulation on recurrent thrombosis and bleeding after hematopoietic cell transplantation

History of venous thromboembolism (VTE) is prevalent among patients undergoing hematopoietic cell transplantation (HCT). Management of anticoagulation is particularly challenging as most patients will have chemotherapy-induced thrombocytopenia while awaiting engraftment post-HCT. We conducted a retrospective study of autologous and allogeneic HCT recipients with prior VTE from 2006-2015 to 1) compare anticoagulant strategies on short-term VTE recurrence and bleeding and 2) assess predictors for VTE recurrence beyond 30 days. Patients with VTE were allocated to two cohorts based on anticoagulant strategy at thrombocytopenia onset and underwent inverse probability weighting to assess primary outcomes of VTE recurrence and bleeding within 30 days post-HCT. Subsequently, multivariable logistic regression model was used to assess the association of 100-day VTE recurrence by the HIGH-2-LOW VTE risk assessment score and whether patients resumed anticoagulation at platelet recovery. Thirteen percent of recipients had VTE prior to HCT; of those meeting inclusion criteria, 227 continued anticoagulation and 113 temporarily discontinued it. Anticoagulant strategy was not significantly associated with decreased risk of VTE recurrence within 30 days (3% vs 4%, p = 0.61); however, risk of overall bleeding was non-significantly higher in those who continued vs discontinued anticoagulation (41% vs 31%, p = 0.08). In a subgroup of 250 allogeneic HCT patients, every one-point increase of HIGH-2-LOW score was significantly associated with VTE recurrence at 100 days (OR 1.57 [95% CI 1.10-2.23]), while anticoagulation resumption upon platelet engraftment was associated with lower recurrent risk (OR 0.48 [0.20-1.14]). Temporarily withholding anticoagulation during thrombocytopenia may optimize risk-benefit tradeoffs, though additional strategies are essential to prevent VTE recurrence after hematopoietic recovery.

Pulmonary Thromboembolism in Immune Thrombocytopenia: A Report of Five Cases and a Review of the Literature

Objective

To provide a reference for the diagnosis and treatment of patients with immune thrombocytopenia (ITP) complicated with pulmonary thromboembolism (PTE) by analyzing the clinical characteristics of five such patients.

Methods

This paper summarizes the clinical manifestations and hematological indexes of five patients with ITP complicated with pulmonary embolism.

Results

In this study, the incidence of ITP complicated with PTE was 2.75%. All five cases were elderly patients with nonspecific clinical manifestations. Platelet counts were different when PTE occurred. The time from the diagnosis of ITP to the occurrence of PTE was from 5 to 24 months, with an average of 12.8 months. There was no significant change in hemoglobin, white blood cell levels, prothrombin time, activated partial thromboplastin time, thrombin time, fibrinogen levels, or the international normalized ratio. Four patients had significantly increased D-dimer levels, while D-dimer was only slightly increased in one patient. Antithrombin (AT) was significantly decreased in four cases (less than 70%), and C-reactive protein (CRP) was increased in all five cases.

Conclusion

PTE may be related to AT and CRP in patients with ITP, which is of great clinical significance to the diagnosis and treatment of ITP complicated with PTE.

Risk of pulmonary emboli after removal of an upper extremity central catheter associated with a deep vein thrombosis

Standard treatment of catheter-associated upper extremity deep vein thrombosis (UE-DVT) is anticoagulation, although catheters are often removed for this indication. The optimal time for catheter removal and whether the act and/or timing of catheter removal is associated with pulmonary embolism (PE) remain unknown. A retrospective cohort study was performed at 8 participating institutions through the Venous thromboEmbolism Network US. Patients with hematologic malignancies and central venous catheter (CVC)-associated UE-DVT were included from 1 January 2010 through 31 December 2016. The primary outcome was objectively confirmed PE within 7 days of UE-DVT diagnosis in anticoagulated patients comparing early (≤48 hours) vs delayed (>48 hours) catheter removal. A total of 626 patients were included, among whom 480 were treated with anticoagulation. Among anticoagulated patients, 255 underwent early CVC removal, while 225 had delayed or no CVC removal; 146 patients received no anticoagulation, among whom 116 underwent CVC removal alone. PE within 7 days occurred in 2 patients (0.78%) with early removal compared with 1 patient (0.44%) with delayed or no CVC removal (P > .9). PE or any cause of death within 7 days occurred in 3 patients in both the early removal (1.18%) and delayed/no removal (1.33%) groups (P > .9). In patients treated with CVC removal only (no anticoagulation), there were no PEs but 3 deaths within 7 days. In patients with hematological malignancy and CVC-associated UE-DVT, early removal of CVCs was not associated with an increased risk of PE compared with delayed or no removal.

Thrombosis in hematological malignancies: mechanisms and implications

A B S T R A C T Thrombotic events are a major cause of morbidity and mortality in cancer. While the association of venous thromboembolic events with cancer is well documented, in recent years arterial events (i.e. acute myocardial infarction and ischemic strokes) have also emerged as relatively common complications among cancer patients. In hematological malignancies incorporating a heterogeneous group of diseases, the prediction of thrombosis occurrence and/or recurrence is challenging, due to unique disease characteristics. Furthermore, the treatment of thrombosis in these patients is often complicated because of disease- or therapy-related thrombocytopenia. In addition, patients with hematological cancers are poorly represented in randomized control clinical trials; hence, evidence-based guidelines are limited. This review will discuss the incidence of venous and arterial thrombotic events in common myeloid and lymphoproliferative diseases. Several new mechanisms contributing to cancer- associated thrombosis will be elaborated. The complicated issue of risk assessment and management of venous thrombosis in patients with hematological malignancies will be delineated.

HIGH-2-LOW risk model to predict venous thromboembolism in allogeneic transplant patients after platelet engraftment

Venous thromboembolism (VTE) after allogeneic hematopoietic cell transplantation (HCT) is a significant treatment-associated complication, although optimal timing of thromboprophylaxis remains uncertain when weighing concurrent risks of bleeding. We aimed to derive and internally validate a risk assessment model (RAM) using patients who underwent first allogeneic HCT from 2006 through 2015 (n = 1703). Index date was defined as the 30th day after transplant, at which point we estimated >75% of patients would have achieved platelet engraftment >50 × 109/L. Stepwise logistic regression modeling was used for model development, and internal validation was achieved by fitting a logistic regression model with 1000 bootstrapped resamples to estimate the optimism-corrected c-statistic. The final RAM, "HIGH-2-LOW," included 7 predictors obtained at 30 days after transplant: History of catheter-related deep venous thrombosis (DVT), Inpatient at day 30, Graft-versus-host disease grade 3 to 4, History of pulmonary embolism or lower-extremity DVT, Lymphoma diagnosis, Obesity with body mass index ≥35 kg/m2, and White blood cell count ≥11 × 109/L. Approximately 16% of patients were stratified as high risk, with incident VTE rate of 10.3% at 100 days compared with 1.5% for those at low risk. VTE odds ratios at 100 days were 5.87 (95% confidence interval [CI], 2.98-11.57) and 2.71 (95% CI, 1.38-5.35) in the high- and intermediate-risk vs low-risk groups, respectively. HIGH-2-LOW model serves as a novel and potentially clinically meaningful tool to identify high-risk allogeneic HCT patients who may benefit from early thromboprophylaxis after platelet engraftment.

Treatment of catheter-related thrombosis in patients with hematologic malignancies: A Venous thromboEmbolism Network U.S. retrospective cohort study

INTRODUCTION

Optimal treatment of catheter-related thrombosis (CRT) is uncertain in patients with hematologic malignancy. We aimed to evaluate the treatment strategies, outcomes, and predictors of recurrent venous thromboembolism (VTE) associated with catheter-related thrombosis (CRT) in patients with hematologic malignancy.

METHODS

We performed a multicenter retrospective cohort study of eight institutions through the Venous thromboEmbolism Network US. Patients with hematologic malignancies with documented CRT were identified using ICD-9 and ICD-10 diagnostic codes. Semi-competing risks proportional hazard regression models were created.

RESULTS AND CONCLUSIONS

Of the 663 patients in the cohort, 124 (19%) were treated with anticoagulation alone, 388 (58%) were treated with anticoagulation and catheter removal, 119 (18%) treated with catheter removal only, and 32 (5%) had neither catheter removal nor anticoagulation. 100 (15%) patients experienced a recurrent VTE event. In the 579 patients who had catheter removal, the most common reason for catheter removal was the CRT [392 (68%)]. For subjects who received any anticoagulation (n = 512), total anticoagulation duration was not associated with VTE recurrence [1.000 (0.999-1.002)]. After adjustment patients treated with catheter removal only had an increased risk of VTE recurrence [2.50 (1.24-5.07)] and death [4.96 (2.47-9.97)]. Patients with no treatment had increased risk of death [16.81 (6.22-45.38)] and death after VTE recurrence [27.29 (3.13-238.13)]. In this large, multicenter retrospective cohort, we found significant variability in the treatment of CRT in patients with hematologic malignancy. Treatment without anticoagulation was associated with recurrent VTE.

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.

Assessing inpatient platelet ordering practice: evaluation of computer provider order entry overrides

BACKGROUND AND OBJECTIVES

Judicious utilization of platelet products protects a limited resource and mitigates risks of transfusion. At many institutions, computer physician order entry systems provide prompts to guide transfusion decisions; many capture the indication for transfusion, and generate metadata when orders are dissonant with guidelines. We conducted a retrospective review to examine adherence to and overrides of hospital guidelines for platelet transfusion to identify opportunities for improved transfusion practice.

MATERIALS AND METHODS

Physician override reports (1/1/2018-3/31/2019) were examined and physician-entered justification comments accompanying override orders were extracted, in addition to patient-specific data (clinical service, age, sex, and pretransfusion platelet count). Two transfusion medicine physicians independently assessed comments in context of patient data and institutional guidelines and categorized as: indicated, protocol driven, or not indicated. Following adjudication, consensus was reached between the two reviewers. Override keyword frequencies were also determined.

RESULTS

Over 15-months, 1373 override orders were placed for 558 unique patients (25% of all adult inpatient platelet transfusions). haematology/oncology providers placed 573 (42%) override orders (261 unique patients), 46% of which were categorized as "not indicated", based on consensus review. Overall, 470 (34%) override orders were categorized as "not indicated". Examples of recurring key words included "bleeding/risk of bleeding", "falling platelet count", "platelet goal of XX".

CONCLUSIONS

A large percentage of override orders for platelet transfusions were determined to be "not indicated" and out of compliance with institutional guidelines. The metadata captured identified concerns regarding clinical transfusion practice and opportunities for revised indications (e.g. threshold for retinal haemorrhage).

Incidence of Upper Extremity Deep Vein Thrombosis in Acute Leukemia and Effect on Mortality

The cumulative incidence, risk factors, rate of subsequent venous thromboembolism (VTE) and bleeding and impact on mortality of isolated upper extremity deep vein thrombosis (UE DVT) in acute leukemia are not well-described. The California Cancer Registry, used to identify treated patients with acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL) diagnosed between 2009 and 2014, was linked with the statewide hospitalization database to determine cumulative incidences of UE DVT and subsequent VTE and bleeding after UE DVT diagnosis. Cox proportional hazards regression models were used to assess the association of UE DVT on the risk of subsequent pulmonary embolism (PE) or lower extremity deep vein thrombosis (LE DVT) and subsequent bleeding, and the impact of UE DVT on mortality. There were 5,072 patients identified: 3,252 had AML and 1,820 had ALL. Three- and 12-month cumulative incidences of UE DVT were 4.8% (95% confidence interval [CI]: 4.1–5.6) and 6.6% (95% CI: 5.8–7.5) for AML and 4.1% (95% CI: 3.2–5.1) and 5.9% (95% CI: 4.9–7.1) for ALL, respectively. Twelve-month cumulative incidences of subsequent VTE after an incident UE DVT diagnosis were 5.3% for AML and 12.2% for ALL. Twelve-month cumulative incidences of subsequent bleeding after an incident UE DVT diagnosis were 15.4% for AML and 21.1% for ALL. UE DVT was associated with an increased risk of subsequent bleeding for both AML (hazard ratio [HR]: 2.07; 95% CI: 1.60–2.68) and ALL (HR: 1.62; 95% CI: 1.02–2.57) but was not an independent risk factor for subsequent PE or LE DVT for either leukemia subtype. Isolated incident UE DVT was associated with increased leukemia-specific mortality for AML (HR: 1.42; 95% CI: 1.16–1.73) and ALL (HR: 1.80; 95% CI: 1.31–2.47). UE DVT is a relatively common complication among patients with AML and ALL and has a significant impact on bleeding and mortality. Further research is needed to determine appropriate therapy for this high-risk population.

Cancer-associated thromboembolism: antithrombotic management of hospitalized patients

Cancer increases risk for venous thromboembolism. Incident thrombocytopenia increases hemorrhagic risk. Hospitalized adults with a cancer diagnosis who received subcutaneous dalteparin in doses adjusted according to platelet count were retrospectively evaluated. Outcomes of interest included nadir platelet counts, transfusions, thromboembolism, and hemorrhage. During a 2-year period of observation, 1854 cancer patients received individualized inpatient treatment with dalteparin. Transfusion was required in 38 of 77 (49.4%) patients with nadir platelet counts < 25 × 10⁹ cells/L as compared with 16 of 75 (21.3%) patients whose nadir platelet counts were 25-50 × 10⁹ cells/L [risk ratio (RR) 2.31; 95% CI 1.42 to 3.78, p < 0.001] and 45 of 1657 (2.7%) patients with platelet counts > 50 × 10⁹ cells/L (RR - 8.07; 95% CI - 4.79 to - 13.59, p < 0.001). Transfusions were administered primarily as supportive therapy. Among transfusion recipients, new or recurrent venous thromboembolism was documented in 2.6%, 0%, and 2.2% of patients with nadir platelet counts of < 25, 25-50, or > 50 × 10⁹ cells/L, respectively (p > 0.9 for all comparisons). Acute blood loss or major bleeding was documented in 10.5%, 12.5%, and 15.6% of patients with platelet counts of < 25, 25-50, or > 50 × 10⁹ cells/L, respectively (p > 0.9 for all comparisons). Among hospitalized cancer patients who received individualized dalteparin treatment, transfusion requirements varied inversely with platelet count. Irrespective of platelet counts, occurrence rates for venous thromboembolism and acute hemorrhage were similar across all treatment groups. Individualized dalteparin treatment provided a consistent pattern of safety and effectiveness.

Anticoagulation in thrombocytopenic patients with hematological malignancy: A multinational clinical vignette-based experiment

BACKGROUND

Thrombocytopenia in cancer patients with an indication for anticoagulation poses a unique clinical challenge. There are guidelines for the setting of venous thromboembolism but not atrial fibrillation (AF). Evidence is lacking and current practice is unclear.

OBJECTIVE

To identify patient and physician characteristics associated with anticoagulation management in hematological malignancy and thrombocytopenia.

METHODS

A clinical vignette-based experiment was designed. Eleven hematologists were interviewed, identifying 5 relevant variable categories with 2-5 options each. Thirty hypothetical vignettes were generated. Each physician received 5 vignettes and selected a management strategy (hold anticoagulation; no change; transfuse platelets; modify type/dose). The survey was distributed to hematologists and thrombosis specialists in 3 countries. Poisson regression models with cluster robust variance estimates were used to calculate relative risks for using one management option over the other, for each variable in comparison to a reference variable.

RESULTS

168 physicians answered 774 cases and reported continuing anticoagulation for venous thromboembolism or AF in 607 (78%) cases, usually with dose reduction or platelet transfusion support. Overall, management was affected by platelet count, anticoagulation indication, time since indication, type of hematological disease and treatment, and prior major bleeding, as well as physician demographics and practice setting. The CHA₂DS₂-VASc score and time since AF diagnosis affected anticoagulation management in AF.

CONCLUSION

This study indicates what the widely accepted management strategies are. These strategies, and possibly others, should be assessed prospectively to ascertain effectiveness. The decision process is intricate and compatible with current venous thromboembolism guidelines.

Platelet cut-off for anticoagulant therapy in thrombocytopenic patients with blood cancer and venous thromboembolism: an expert consensus

BACKGROUND

Management of venous thromboembolism (VTE) in patients with haematologic malignancies and thrombocytopenia is clinically challenging due to the related risks. No prospective studies or clinical trials have been carried out and, therefore, no solid evidence on this compelling issue is available.

METHODS

Given this, an expert panel endorsed by the Gruppo Italiano Malattie Ematologiche dell'Adulto Working Party on Thrombosis and Haemostasis was set up to produce a formal consensus, according to the RAND method, in order to issue clinical recommendations about the platelet (PLT) cut-off for safe administration of low molecular weight heparin (LMWH) in thrombocytopenic (PLT <100×109/L) adult patients with haematologic malignancies affected by acute (<1 month) or non-acute VTE.

RESULTS

In acute VTE, the panel suggests safe anticoagulation with LMWH at therapeutic doses for PLT between ≥50<100×109/L and at 50% dose reduction for PLT ≥30<50×109/L. In acute VTE for PLT <30×109/L, the following interventions are recommended: positioning of an inferior vena cava (IVC) filter with prophylactic LMWH administration and platelet transfusion. In non-acute VTE, anticoagulation with LMWH at therapeutic doses for PLT between ≥50<100×109/L or over and at 50% dose reduction for PLT ≥30<50×109/L is considered appropriate. The discontinuation of full or reduced therapeutic dose of LMWH is recommended for PLT <30×109/L, both in acute and non-acute VTE.

DISCUSSION

We suggest using dose-adjusted LMWH according to PLT to optimise anticoagulant treatment in patients at high bleeding risk.

Current Management of Cancer-associated Venous Thromboembolism: Focus on Direct Oral Anticoagulants

Cancer-associated venous thromboembolism (CAT) is a common complication associated with high morbidity and mortality. In accordance with major clinical trials comparing low-molecular-weight heparin (LMWH) with a vitamin K antagonist (VKA), LMWH is currently the standard treatment for CAT, owing to its efficacy for thrombosis recurrence and improved safety profile compared to VKA. Over the past few years, direct oral anticoagulants (DOACs) have emerged as potential alternative therapies to LMWH due to their convenient route of administration and predictable pharmacokinetics, but evidence for their use in CAT is inconclusive, as only a small fraction of the study populations in these trials had CAT. Recently, two large head-to-head trials comparing DOACs to LMWH in CAT patients reported comparable efficacies of DOACs with increased bleeding risk. Occasionally, CAT treatment can be challenging due to the heterogeneity of underlying malignancies and comorbidities. Renal insufficiency and gastrointestinal defects are the main obstacles in anticoagulant selection. Careful choice of treatment candidates and proper anticoagulant strategies are critical for the treatment of CAT; hence, more studies are required to address these challenges.

Management of anticoagulation for cancer-associated thrombosis in patients with thrombocytopenia: A systematic review

BACKGROUND

The management of anticoagulation for cancer-associated thrombosis (CAT) in patients with thrombocytopenia is controversial. Whereas some studies suggest that administration of reduced-dose low-molecular-weight heparin (LMWH) or temporary discontinuation for moderate and severe thrombocytopenia may be a safe and effective, others suggest full-dose anticoagulation with transfusion support. We sought to address this important knowledge gap and summarize the literature comparing these two common management strategies.

METHODS

A systematic review of the literature (PROSPERO CRD42017077127) using MEDLINE (inception to September 2017) was conducted. We included studies that reported recurrent venous thromboembolism (VTE) and major bleeding complications among patients treated with both of the two most common management strategies: therapeutic anticoagulation with platelet transfusion support and dose-modified anticoagulation for periods when the platelet count is <50 × 109/L.

RESULTS

A total of 134 article records were identified on the initial search and 10 articles underwent full text review. Two observational studies met the inclusions criteria. A total of 121 patients with CAT and thrombocytopenia were included. Forty-two of these patients had pulmonary embolism and 87 had deep vein thrombosis (DVT) including 38 upper extremity DVT. Overall, 27% of patients, regardless of their treatment strategy, experienced recurrent VTE. Thirteen percent of anticoagulated patients (15% of all patients) experienced a major bleeding episode. Meta-analysis could not be conducted.

CONCLUSIONS

Our findings do not support one management strategy over another to treat CAT patients with thrombocytopenia. However, the data highlights the heightened risk of recurrent VTE in this patient population despite the thrombocytopenia.

Patients treated for acute VTE during periods of treatment-related thrombocytopenia have high rates of recurrent thrombosis and transfusion-related adverse outcomes

Venous thromboembolism (VTE) is a common complication of hematologic malignancies. Prolonged periods of thrombocytopenia are experienced universally by patients undergoing treatment for these diseases, yet data to guide management of anticoagulation in this setting are lacking. To obtain data on the management and outcomes of VTE in patients with thrombocytopenia related to the treatment of hematologic malignancies. This was an observational cohort study of patients experiencing VTE during periods of treatment-related thrombocytopenia over a 5-year period at the Fred Hutchinson Cancer Research Center. Medical records were reviewed for diagnostic, treatment and outcomes data, including bleeding events (categorized by WHO criteria) and progression or recurrence of VTE. Eighty-two patients meeting inclusion criteria were identified. Forty-eight percent were male and the median age was 55. Sixty-seven patients received anticoagulation, 88% of these were managed with transfusion support for a platelet goal of 50 × 10⁹/L. Thirty-one patients experienced bleeding events, 22 of which were grade 2 and nine of which were grade 3/4. The median platelet count at the time of bleeding event was 54 × 10⁹/L. Seven patients experienced progression of thrombosis and/or recurrence. Eleven patients experienced transfusion reactions and 30 experienced volume overload requiring diuretics or dialysis. While bleeding events were not uncommon, the majority of events were non-major/non-clinically relevant. Most bleeding events occurred while the platelet count was within the 'goal' range of ≥50 × 10⁹/L, and many patients experienced transfusion related adverse events. Prospective studies are urgently needed to identify the optimal transfusion strategy for these patients.

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.