Bleeding complications during anticoagulant treatment in patients with cancer

Ischemic stroke in cancer patients: A review of an underappreciated pathology

Currently 1 in 10 patients with ischemic stroke have comorbid cancer, and this frequency is expected to increase with continued advances in cancer therapeutics prolonging median survival. Well known for its association with venous thrombosis, cancer has recently emerged as a significant risk factor for arterial thromboembolism, including stroke; however, the underlying mechanisms are uncertain. In addition, the optimal strategies to prevent and acutely treat stroke in cancer patients are yet to be established. This review summarizes the current evidence on ischemic stroke risk, biomarkers, pathophysiology, treatments, and prognosis in cancer patients, emphasizing knowledge gaps and the potential strategies to address them. Ann Neurol 2018;83:873-883.

[Direct oral anticoagulants (DOACS): A necessary focus]

In 2008, we decided to enter the era of direct oral anticoagulants (DOACS). Was that the right decision to make? The answer will depend on how well we meet the conditions of proper use. This means avoiding underdosing and overdosing as well as understanding how DOACS were validated so that our prescriptions fulfill their role in the management of thrombotic disease.

CHA2DS2-VASc score and risk of thromboembolism and bleeding in patients with atrial fibrillation and recent cancer

Background

Cancer may influence the risk of thromboembolism and bleeding associated with the CHA2DS2-VASc score. We examined the risk of thromboembolism and bleeding associated with the CHA2DS2-VASc score in atrial fibrillation patients with and without recent cancer.

Methods and results

Using nationwide registers all patients diagnosed with atrial fibrillation from 2000 to 2015 and not on oral anticoagulation or heparin therapy were included and followed for 2 years. Recent cancer was defined by a cancer diagnosis 5 years or fewer earlier. Risks of thromboembolism and bleeding were estimated in cumulative incidence curves and Cox regression models. We included 122,053 patients with incident atrial fibrillation, 12,014 (10%) had recent cancer. The 2-year cumulative incidence of thromboembolism and bleeding in patients with versus without recent cancer was 1.7% (95% confidence interval (CI) 0.5–2.8) and 4.3% (95% CI 2.4–6.2) versus 1.2% (95% CI 0.9–1.5) and 1.7% (95% CI 1.4–2.0) for CHA2DS2-VASc score 0; 3.2% (95%CI 2.2-4.3) and 4.4% (95%CI 3.2-5.6) versus 1.8% (95%CI 1.6-2.1) and 3.0% (95% CI 2.7–3.3) for CHA2DS2-VASc score 1; and 7.1% (95% CI 6.6–7.7) and 6.8% (95% CI 6.3–7.2) versus 10.9% (95% CI 10.7–11.1) and 6.2% (95% CI 6.1–6.4) for CHA2DS2-VASc score 2 or greater. Although the CHA2DS2-VASc score was associated with thromboembolism and bleeding in both patients with and without cancer, the association differed between the groups for thromboembolism (test for interaction, p < 0.001) and bleeding (test for interaction, p < 0.001).

Conclusion

The association of the CHA2DS2-VASc score and risk of thromboembolism and bleeding differed between atrial fibrillation patients with and without recent cancer. Therefore, the CHA2DS2-VASc score should be used with caution in patients with recent cancer.

Cardiovascular Adverse Events in Patients With Cancer Treated With Bevacizumab: A Meta-Analysis of More Than 20 000 Patients

Background

The monoclonal antibody bevacizumab effectively inhibits angiogenesis in several types of cancers by blocking vascular endothelial growth factor. However, life‐threatening cardiovascular adverse effects could limit its use and may warrant specific follow‐up strategies.

Methods and Results

We systematically searched MEDLINE, Cochrane, EMBASE, and Web of Science for randomized controlled trials published until November 2016 that assessed patients with cancer treated with or without bevacizumab in addition to standard chemotherapy. A total of 20 050 patients with a broad range of cancer types from 22 studies were included in this analysis (10 394 in the bevacizumab group and 9656 in the control group). The risks of arterial and venous adverse events were higher in the bevacizumab groups (relative risk [RR], 1.37; 95% CI, 1.10–1.70 [P=0.004] and RR, 1.29; 95% CI, 1.12–1.47 [P<0.001], respectively), and more arterial adverse events occurred in patients taking high‐dose bevacizumab regimens. Bevacizumab treatment was associated with the highest risk of cardiac and cerebral ischemia in the high‐dose bevacizumab groups (RR, 4.4; 95% CI, 1.59–12.70 [P=0.004] and RR, 6.67; 95% CI, 2.17–20.66 [P=0.001], respectively). In addition, the risk of bleeding and arterial hypertension were higher in the bevacizumab groups (RR, 2.74; 95% CI, 2.38–3.15 [P<0.001] and RR, 4.73; 95% CI, 4.15–5.39 [P<0.00001], respectively), with higher values for patiens taking high‐dose regimens.

Conclusions

Treatment with bevacizumab increases the risk of arterial adverse events, particularly cardiac and cerebral ischemia, venous adverse events, bleeding, and arterial hypertension. This risk is additionally increased with high doses of bevacizumab. Further studies should determine the appropriate options for cardio‐oncology management.

Clinical Trial Registration

URL: https://www.crd.york.ac.uk. Unique identifier: PROSPERO(CRD42016054305).

Asymptomatic Lower Extremity Deep Vein Thrombosis - Clinical Characteristics, Management Strategies, and Long-Term Outcomes

BACKGROUND

The prognosis of asymptomatic deep vein thrombosis (DVT) is uncertain and there is no consensus on the necessity of detection and treatment.Methods and Results:We retrospectively evaluated 300 patients with asymptomatic lower extremity DVT screened from 4,514 consecutive patients on ultrasound at Kyoto University Hospital between January 2010 and September 2015. The subjects had concomitant active cancer in 40%, unprovoked DVT in 59%, and distal DVT in 70%. The cumulative 5-year incidences of symptomatic recurrent venous thromboembolism (VTE); major bleeding; and all-cause death were 14.5%, 16.6%, and 34.1%, respectively. Among 232 patients (77%) with prolonged anticoagulant therapy, anticoagulants were discontinued in 48.4% at 1 year. Anticoagulant therapy was associated with a significantly higher incidence of major bleeding compared with the non-anticoagulant group (20.5% vs. 1.5%, P=0.01) with no significant effect on the incidence of VTE. In patients with active cancer, the favorable effect of anticoagulants relative to no anticoagulants for VTE was significant (HR, 0.22; 95% CI: 0.05-0.95).

CONCLUSIONS

Prolonged anticoagulants therapy was implemented in the majority of patients with asymptomatic DVT, but was associated with a significantly higher risk for major bleeding. On subgroup analysis in patients with active cancer, however, there appeared to be a benefit of prolonged anticoagulant therapy in decreasing the rate of symptomatic recurrent VTE.

Rivaroxaban-induced chest wall spontaneous expanding hematoma

Rivaroxaban is an oral direct Factor Xa inhibitor approved in the European Union and the United Sates for the single-drug treatment of several thromboembolic diseases in adults. Ιt has been evaluated in large phase III clinical trials and has been found to have similar efficacy and safety with standard therapy. Herein, is described a very rare case of a rivaroxaban-induced spontaneous expanding chest wall hematoma, that required surgical intervention, in a breast cancer patient. Use of the Naranjo adverse drug reaction probability scale indicated a probable relationship (score of 7) between the patient's development of hematoma and treatment with rivaroxaban. Physicians should be cautious when prescribing rivaroxaban in groups of patients associated with increased bleeding risk such as patients with impaired renal or hepatic function, hypertension, coronary heart disease, heart failure, patients with certain types of cancers and patients receiving concomitant medications which may alter the pharmacokinetic or pharmacodymamic parameters of rivaroxaban. Anticoagulant treatment should be tailored to each individual patient weighing the bleeding risk against the risk of recurrent thrombosis.

Primary prophylaxis for venous thromboembolism in ambulatory cancer patients receiving chemotherapy

BACKGROUND

Venous thromboembolism (VTE) often complicates the clinical course of cancer. The risk is further increased by chemotherapy, but the trade-off between safety and efficacy of primary thromboprophylaxis in cancer patients treated with chemotherapy is uncertain. This is the second update of a review first published in February 2012.

OBJECTIVES

To assess the efficacy and safety of primary thromboprophylaxis for VTE in ambulatory cancer patients receiving chemotherapy compared with placebo or no thromboprophylaxis.

SEARCH METHODS

For this update the Cochrane Vascular Information Specialist searched the Cochrane Vascular Group Specialised Register (June 2016). In addition, the Information Specialist searched the Cochrane Central Register of Controlled Trials (CENTRAL) (2016, Issue 5). Clinical trials registries were searched up to June 2016.

SELECTION CRITERIA

Randomised controlled trials comparing any oral or parenteral anticoagulant or mechanical intervention to no thromboprophylaxis or placebo, or comparing two different anticoagulants.

DATA COLLECTION AND ANALYSIS

We extracted data on methodological quality, participant characteristics, interventions, and outcomes including symptomatic VTE and major bleeding as the primary effectiveness and safety outcomes, respectively.

MAIN RESULTS

We identified five additional randomised controlled trials (2491 participants) in the updated search, considering in this update 26 trials with a total of 12,352 participants, all evaluating pharmacological interventions and performed mainly in people with locally advanced or metastatic cancer. The quality of the evidence ranged from high to very low across the different outcomes and comparisons. The main limiting factors were imprecision and risk of bias. One large trial of 3212 participants found a 64% (risk ratio (RR) 0.36, 95% confidence interval (CI) 0.22 to 0.60) reduction of symptomatic VTE with the ultra-low molecular weight heparin (uLMWH) semuloparin relative to placebo, with no apparent difference in major bleeding (RR 1.05, 95% CI 0.55 to 2.00). When compared with no thromboprophylaxis, LMWH significantly reduced the incidence of symptomatic VTE (RR 0.54, 95% CI 0.38 to 0.75; no heterogeneity, Tau2 = 0.00%) with a non-statistically significant 44% higher risk of major bleeding events (RR 1.44, 95% CI 0.98 to 2.11). In participants with multiple myeloma, LMWH was associated with a significant reduction in symptomatic VTE compared with the vitamin K antagonist warfarin (RR 0.33, 95% CI 0.14 to 0.83), while the difference between LMWH and aspirin was not statistically significant (RR 0.51, 95% CI 0.22 to 1.17). Major bleeding was observed in none of the participants treated with LMWH or warfarin and in less than 1% of those treated with aspirin. Only one study evaluated unfractionated heparin against no thromboprophylaxis but did not report on VTE or major bleeding. When compared with placebo, warfarin was associated with a non-statistically significant reduction of symptomatic VTE (RR 0.15, 95% CI 0.02 to 1.20). Antithrombin, evaluated in one study involving paediatric patients, had no significant effect on VTE or on major bleeding when compared with no antithrombin. The direct oral factor Xa inhibitor apixaban was evaluated in a phase II dose-finding study that suggested a low rate of major bleeding (2.1% versus 3.4%) and symptomatic VTE (1.1% versus 13.8%) in comparison with placebo.

AUTHORS' CONCLUSIONS

In this second update, we confirmed that primary thromboprophylaxis with LMWH significantly reduced the incidence of symptomatic VTE in ambulatory cancer patients treated with chemotherapy. In addition, the uLMWH semuloparin, which is not commercially available, significantly reduced the incidence of symptomatic VTE. The risk of major bleeding associated with LMWH, while not reaching statistical significance, suggest caution and mandate additional studies to determine the risk-to-benefit ratio of LMWH in this setting. Despite the encouraging results of this review, routine prophylaxis in ambulatory cancer patients cannot be recommended before safety issues are adequately addressed. We need additional studies investigating targeted primary prophylaxis in people with specific types or stages of cancer associated with a higher risk of VTE.

Pharmacology of Heparin and Related Drugs

Heparin has been recognized as a valuable anticoagulant and antithrombotic for several decades and is still widely used in clinical practice for a variety of indications. The anticoagulant activity of heparin is mainly attributable to the action of a specific pentasaccharide sequence that acts in concert with antithrombin, a plasma coagulation factor inhibitor. This observation has led to the development of synthetic heparin mimetics for clinical use. However, it is increasingly recognized that heparin has many other pharmacological properties, including but not limited to antiviral, anti-inflammatory, and antimetastatic actions. Many of these activities are independent of its anticoagulant activity, although the mechanisms of these other activities are currently less well defined. Nonetheless, heparin is being exploited for clinical uses beyond anticoagulation and developed for a wide range of clinical disorders. This article provides a "state of the art" review of our current understanding of the pharmacology of heparin and related drugs and an overview of the status of development of such drugs.

Safety of anticoagulation in the treatment of venous thromboembolism in patients with haematological malignancies and thrombocytopenia: Report of 5 cases and literature review

Venous thromboembolism (VTE) is relatively common among patients with haematological malignancies. Management is challenging because many of these patients are also thrombocytopenic and at increased risk of bleeding. Current recommendations regarding the treatment of VTE in thrombocytopenic patients with haematological malignancies are limited as there only few studies evaluating the safety and efficacy of anticoagulation in this population of patient. A literature review on the safety of antithrombotic therapy for treatment or prophylaxis of VTE in patients with haematological malignancies was undertaken. This includes a report on 5 patients with haematological malignancies at our institute who received enoxaparin for treatment of VTE while thrombocytopenic. Unlike previous case series which showed that the use of LMWH (low molecular weight heparin) is safe in this group of patients, major bleeding occurred in 2 patients, and was fatal in one case. More studies are required to evaluate the risk factors and safety of anticoagulation in these patients.

Chemical Conjugate of Low Molecular Weight Heparin and Suramin Fragment Inhibits Tumor Growth Possibly by Blocking VEGF165

Low molecular weight heparin (LMWH) and its derivatives have been reported to possess antiangiogenic effect via electrostatic interaction with various angiogenic growth factors such as VEGF165. However, clinical applications of LMWH for anticancer therapy have been restricted due to its anticoagulant effect and insufficient therapeutic efficacy. To overcome these limitations and enhance the antiangiogenic efficacy, LMWH was conjugated with suramin fragments that have a binding affinity to the heparin-binding domain (HBD) of proteins. The conjugation of suramin fragments to LMWH enhanced the antiangiogenic effect of LMWH by increasing the binding affinity to VEGF165, while decreasing its anticoagulant activity. The chemical conjugate of LMWH and suramin fragments (LHsura) showed a substantial inhibitory effect on VEGF165-mediated cell proliferation, migration, and tube formation of HUVECs without significant cytotoxicity in vitro. Finally, we confirmed the anticancer effect of LHsura (61.4% vs control) in a SCC7-bearing mouse model.

Oral anticoagulant therapy in atrial fibrillation patients at high stroke and bleeding risk

Atrial fibrillation (AF) is associated with a 5-fold greater risk of ischemic stroke or systemic embolism compared with normal sinus rhythm. Cardioembolic AF-related strokes are often more severe, fatal or associated with greater permanent disability and higher recurrence rates than strokes of other aetiologies. These strokes may be effectively prevented with oral anticoagulant (OAC) therapy, using either vitamin K antagonists (VKAs) or non-vitamin K antagonist OACs (NOACs) such as the direct thrombin inhibitor dabigatran or direct factor Xa inhibitors rivaroxaban, apixaban or edoxaban. Most AF patients have a positive net clinical benefit from OAC, excluding those with AF and no conventional stroke risk factors. Balancing the risks of stroke and bleeding is necessary for optimal use of OAC in clinical practice, and modifiable bleeding risk factors must be addressed. Concerns remain over 'non-changeable' bleeding risk factors such as older age, significant renal or hepatic impairment, prior stroke(s) or prior bleeding event(s) and active malignancies. Such AF patients are often termed 'special' AF populations, due to their 'special' risk profile that includes increased risks of both thromboembolic and bleeding events, and due to fear of bleeding complications these AF patients are often denied OAC. Evidence shows, however, that the absolute benefits of OAC are the greatest in patients at the highest risk, and NOACs may offer even a greater net clinical benefit compared to warfarin particularly in these high risk patients. In this review article, we summarize available data on stroke prevention in AF patients at increased risk of both stroke and bleeding and discuss the use of NOACs for thromboprophylaxis in these 'special' AF populations.