Considerations for long-term anticoagulant therapy in patients with venous thromboembolism in the novel oral anticoagulant era

Current Evidence and Expert Opinion on Thromboprophylaxis After Total Knee and Hip Replacement

An effective anticoagulant provides a balance between the risk for venous thromboembolism (VTE) and bleeding and is crucial in achieving optimal clinical outcomes in patients undergoing total hip replacement (THR) and total knee replacement (TKR) surgeries. We performed a review of the literature on thromboprophylaxis for patients undergoing total hip or knee replacement. This review article summarizes current guidelines and evidence for anticoagulation along with the expert opinion about pharmacological VTE prophylaxis, particularly non-Vitamin K antagonist oral anticoagulants (NOACs), for patients after total hip or knee replacement. Aspirin for VTE prophylaxis after TKR/THR has been controversial and most of the evidence is reported from observational research. Although the guidelines do not recommend any specific thromboprophylaxis agent, available evidence suggests that NOACs are as effective as low molecular weight heparins (LMWHs) in preventing VTE. Oral administration and the lack of dose monitoring make NOACs easy to use in outpatient settings in cases with challenging treatment compliances. They can be used for two weeks after TKR and five weeks after THR - six weeks after TKR and THR to cover the at-risk period for VTE post-discharge. Owing to the lack of evidence for a head-to-head comparison of NOACs, an anticoagulant with better efficacy and safety may be suggested in special patient populations (elderly, obese patients, or those with renal dysfunction). The expert opinion on pharmacological VTE prophylaxis provided in this article could address some gaps in the management of anticoagulation in patients with total hip or knee replacement.

Systemic Anticoagulation and Inpatient Outcomes of Pancreatic Cancer: Real-World Evidence from U.S. Nationwide Inpatient Sample

Background: Pancreatic cancer can induce a hypercoagulable state which may lead to clinically apparent thrombosis. However, the effect of anticoagulants remains ambiguous. This study aimed to investigate the potential effect of long-term systemic anticoagulant usage on hospitalization outcomes of patients with pancreatic cancer. Methods: This retrospective study extracted all data from the U.S. Nationwide Inpatient Sample (NIS) database from 2005 to 2018. We included hospitalized adults ≥18 years old with a pancreatic cancer diagnosis identified by International Classification of Diseases ninth revision (ICD-9) and tenth revision (ICD-10) codes. We utilized diagnostic codes ICD9 V58.61 and ICD10 Z79.01, i.e., 'long-term use of anticoagulant', to identify individuals who were on a long-term systemic anticoagulant. The study cohort were then further grouped as being with or without long-term systemic use of an anticoagulant. Propensity score matching was performed to balance the characteristics of the two groups. The risks of life-threatening events, e.g., acute myocardial infarction (AMI), acute heart failure (AHF), sepsis, shock, and acute kidney injury (AKI), in-hospital death, and prolonged length of stay (LOS) in the hospital were compared between the groups by univariable and multivariable logistic regression analyses. Results: The study population consisted of 242,903 hospitalized patients with pancreas cancer, 6.5% (n = 15,719) of whom were on long-term systemic anticoagulants. A multivariable regression analysis showed that long-term systemic anticoagulant use was independently associated with lower odds of sepsis (aOR: 0.81, 95% CI: 0.76-0.85), shock (aOR: 0.59, 95% CI: 0.51-0.68), AKI (aOR: 0.86, 95% CI: 0.81-0.91), in-hospital mortality (aOR: 0.65, 95% CI: 0.60-0.70), and prolonged LOS (aOR: 0.84, 95% CI: 0.80-0.89). Conclusions: Long-term systemic anticoagulant use is associated with better clinical outcomes in terms of decreased risks of some life-threatening events, in-hospital death, and prolonged LOS among hospitalized patients with pancreatic cancer in the U.S.

Development of a Carotid Artery Thrombolysis (iCAT) Stroke Model in Mice

Development of a mouse carotid artery thrombolysis model of stroke.

iCAT enables assessment of adjunctive antithrombotic therapies on arterial recanalization, cerebral perfusion, and stroke outcomes.

Recanalization with restored cerebral perfusion is the primary goal of thrombolytic therapy in acute ischemic stroke. The identification of adjunctive therapies that can be safely used to enhance thrombolysis in stroke remains an elusive goal. We report here the development of a mouse in situ carotid artery thrombolysis (iCAT) stroke model involving graded cerebral ischemia to induce unihemispheric infarction after thrombotic occlusion of the common carotid artery (CCA). Electrolytic-induced thrombotic occlusion of the left CCA enabled real-time assessment of recanalization and rethrombosis events after thrombolysis with recombinant tissue-type plasminogen activator (rtPA). Concurrent transient stenosis of the right CCA induced unihemispheric hypoperfusion and infarction in the left middle cerebral artery territory. Real-time assessment of thrombolysis revealed recanalization rates <30% in rtPA-treated animals with high rates of rethrombosis. Addition of the direct thrombin inhibitor argatroban increased recanalization rates to 50% and reduced rethrombosis. Paradoxically, this was associated with increased cerebral ischemia and stroke-related mortality (25%-42%). Serial analysis of carotid and cerebral blood flow showed that coadministration of argatroban with rtPA resulted in a marked increase in carotid artery embolization, leading to distal obstruction of the middle cerebral artery. Real-time imaging of carotid thrombi revealed that adjunctive anticoagulation destabilized platelet-rich thrombi at the vessel wall, leading to dislodgement of large platelet emboli. These studies confirm the benefits of anticoagulants in enhancing thrombolysis and large artery recanalization; however, at high levels of anticoagulation (∼3-fold prolongation of activated partial thromboplastin time), this effect is offset by increased incidence of carotid artery embolization and distal middle cerebral artery occlusion. The iCAT stroke model should provide important new insight into the effects of adjunctive antithrombotic agents on real-time thrombus dynamics during thrombolysis and their correlation with stroke outcomes.

Evaluation of the efficacy of direct oral anticoagulants (DOACs) in comparison to warfarin in morbidly obese patients

Purpose: There is limited clinical data evaluating anticoagulation with the direct oral anticoagulants (DOACs) in morbidly obese patients. We sought to examine the efficacy in preventing stroke or other systemic embolic events and safety of apixaban, dabigatran, and rivaroxaban, in comparison to warfarin in patients with either a body-mass index (BMI) over 40 kg/m2 and/or a weight over 120 kg.Methods: After approval from IRB, we collected retrospective data from our institution's records on 180 patients. We analyzed the rates of stroke and systemic embolic events as defined as ischemic stroke, pulmonary embolism (PE), deep vein thrombosis (DVT), and myocardial infarction (MI) as well as major bleeding in morbidly obese patients receiving apixaban, dabigatran, or rivaroxaban in comparison to warfarin for anticoagulation due to nonvalvular atrial fibrillation, postoperative thrombus prophylaxis, or DVT/PE treatment and/or reduction in risk for recurrence.Results: The final analysis included 90 patients in both arms. Fifty-two percent (n = 41) of patients in the DOAC group were on apixaban therapy, 12% (n = 11) on dabigatran, and 37% (n = 33) on rivaroxaban. The average BMI and weight in the DOAC group were 46.7 kg/m2 and 139.3 kg, respectively. In the warfarin group, average BMI and weight were 45.8 kg/m2 and 135.9 kg, respectively. There were 11 patients who developed a stroke or thromboembolic event in the DOAC group and 10 in the warfarin group (OR 1.11, 95% confidence interval [CI] 0.45-2.78; p = 0.82). The events in the DOAC group consisted of three patients who developed ischemic stroke, three patients who developed DVTs, one who developed a PE, and four patients who developed MIs. There were two major bleeding events in the DOAC group and three events in the warfarin group (p = 0.65).Conclusions: Anticoagulation therapy with DOACs in morbidly obese patients may be a safe and effective alternative to warfarin for prevention of stroke or systemic embolic events. However, additional studies are necessary to confirm these findings.

Venous Thromboembolism - Current Diagnostic and Treatment Modalities

BACKGROUND:

Pulmonary embolism and deep venous thrombosis, known as venous thromboembolism (VTE), are associated with a high proportion of morbidity and mortality.

AIM:

Aim of this review is to emphasise current diagnostic and therapeutic modalities for VTE.

RESULTS:

No differences have been noticed in European and American guidelines in diagnostic approach of this disorder. Today there is enough clinical information for the use of heparin (either, unfractionated or low molecular) and vitamin K antagonists in the treatment of acute and chronic phases of VTE. Novel oral anticoagulants seem to have some advantages in the treatment of this disorder. Rivaroxaban has been approved widespread, for use as a single-drug approach of VTE.

CONCLUSION:

Both guidelines are almost similar and good basis for evidence-based treatment of this disorder.