Direct Oral Anticoagulants: How Do These Drugs Work, How to Monitor, and What Is Their Role in Orthopaedic Surgery.

Postoperative venous thromboembolism is a major adverse event associated with orthopaedic surgery. With the addition of perioperative anticoagulation and antiplatelet therapy, the rates of symptomatic venous thromboembolism have dropped to 1% to 3%, and as such, practicing orthopaedic surgeons must be familiar with these medications, including aspirin, heparin, or warfarin, and the use of direct oral anticoagulants (DOACs). DOACs are increasingly being prescribed due to their predictable pharmacokinetics and increased convenience, as they do not require routine monitoring, and 1% to 2% of the general population is currently anticoagulated. Although the introduction of DOACs has yielded additional treatment options, this has also led to confusion and uncertainty regarding treatment, specialized testing, and when and what reversal agents are appropriate. This article provides a basic overview of DOAC medications, their suggested use in the perioperative setting, effects on laboratory testing, and consideration for when and how to use reversal agents in orthopaedic patients.

Successful use of lenalidomide to treat refractory acquired von Willebrand disease associated with monoclonal gammopathy.

Acquired von Willebrand syndrome (AVWS) is a rare hematologic disorder characterized by quantitative or qualitative defects of von Willebrand factor (vWF), a protein crucial for normal hemostasis. AVWS has been described in association with several pathologic entities with varied mechanisms. Among these, lymphoproliferative disorders are the most common, with monoclonal gammopathy of undetermined significance (MGUS) being the most frequently reported. AVWS in this setting is commonly associated with the development of bleeding that is clinically challenging to manage due to accelerated clearance of vWF, limiting the utility of many conventional treatment modalities such as DDAVP or vWF/FVIII. We report a case of a 43-year-old male who was sent to our institution for new-onset easy bruising and laboratories concerning for von Willebrand disease (vWD). Further diagnostic workup revealed evidence of an IgG monoclonal gammopathy and findings suggestive of vWF inhibition. Ultimately, he was found to have monoclonal gammopathy of clinical significance (MGCS)-associated AVWS refractory to conventional treatment but responsive to lenalidomide and dexamethasone. This case suggests that lenalidomide may be suitable for patients with AVWS secondary to MGCS.

Utilization of emicizumab in acquired hemophilia A: A case report.

BACKGROUND: Acquired Hemophilia A (AHA) is a rare autoimmune disorder associated with the development of autoantibodies against factor VIII (FVIII). Although obtaining hemostatic control through the use of recombinant factor VIIa, activated prothrombin complex concentrate and recombinant porcine FVIII are cornerstones in the clinical management of AHA, these therapies have several disadvantages, including a higher risk for the development of thromboembolic events, unpredictable efficacy and short half-lives. While emicizumab has been FDA licensed for use in bleeding prophylaxis for patients with Congenital Hemophilia A (CHA) with and without inhibitors, it has not been approved for use in AHA, with only a few reports describing its use in this context. CASE REPORT: We report our experience with the use of emicizumab in an 83-year old male with AHA, complicated by the onset of atrial fibrillation following admission, drug-induced thrombocytopenia, infectious complications, and the identification of a low-grade lymphoproliferative disorder, in which emicizumab prophylaxis was used for bleeding prophylaxis in the context of persistently elevated inhibitor titers without evidence of thrombotic events or thrombotic microangiopathy.

The utility of therapeutic plasma exchange in Hyperviscosity syndrome associated with juvenile rheumatoid arthritis: A case report.

Hyperviscosity syndrome (HVS) is a life-threatening syndrome caused by high concentrations of large plasma proteins like IgM, rheumatoid factor, and other immune complexes, leading to increased blood viscosity and symptoms such as visual abnormalities, neurological impairment, bleeding diathesis, and thrombosis. While Waldenström's macroglobulinemia accounts for 80% to 90% of cases, HVS may develop in other clinical settings characterized by elevations in plasma proteins. Limited evidence currently exists describing the safety and efficacy of therapeutic plasma exchange (TPE) for the management of HVS secondary to non-neoplastic conditions. We report a case of recurrent HVS associated with juvenile rheumatoid arthritis and Felty syndrome that demonstrated improvement in clinical symptoms following initiation of TPE. These findings suggest that TPE may be utilized as an adjunct treatment option in patients with HVS secondary to autoimmune disorders.

Comparison of the Quantra QPlus System With Thromboelastography in Cardiac Surgery.

OBJECTIVES: Use of viscoelastic testing, such as thromboelastography (TEG), is recommended in cardiac surgery to monitor coagulation and to guide the transfusion of blood products. The Quantra QPlus System is a novel point-of-care platform that uses ultrasonic pulses to characterize dynamic changes in viscoelastic properties of a blood sample during coagulation. Despite the ability to assess similar aspects of clot formation, limited studies addressing the interchangeability of viscoelastic testing parameters exist. The primary aim of the present study was to assess the correlation and agreement between Quantra and TEG5000 results using blood samples from cardiac surgery patients. DESIGN: Tertiary care, academic medical center. SETTING: Prospective observational study. PARTICIPANTS: Twenty-eight patients undergoing elective cardiac surgery undergoing cardiopulmonary bypass were evaluated. MEASUREMENTS AND MAIN RESULTS: Perioperative blood samples were collected and assessed using Quantra, and results were compared with TEG and conventional coagulation testing. Method comparison analysis demonstrated that Quantra parameters (Quantra clot time, clot stiffness, and fibrinogen contribution to clot stiffness) significantly correlated with TEG R and TEG G after induction of anesthesia, during cardiopulmonary bypass, and after rewarming (rs = 0.83, rs = 0.84, and rs = 0.73, respectively). However, Quantra parameters demonstrated poor agreement compared with equivalent TEG5000 parameters. CONCLUSIONS: The Quantra QPlus System significantly correlated with TEG5000, suggesting that this test may be used in a similar clinical context. Despite the strength of correlation between Quantra and TEG parameters, measurements are not interchangeable.

Ischemic stroke in a patient with moderate to severe inherited factor VII deficiency.

Thrombosis is known to occur in patients with rare inherited bleeding disorders, usually in the presence of a thrombotic risk factor such as surgery and/or factor replacement therapy, but sometimes spontaneously. We present the case of a 72-year-old African American male diagnosed with congenital factor VII (FVII) deficiency after presenting with ischemic stroke, presumably embolic, in the setting of atherosclerotic carotid artery stenosis. The patient had an international normalized ratio (INR) of 2.0 at presentation, with FVII activity of 6% and normal Extem clotting time in rotational thromboelastometry. He was treated with aspirin (325 mg daily) and clopidogrel (75 mg daily) with no additional bleeding or thrombotic complications throughout his admission. This case provides further evidence that moderate to severe FVII deficiency does not protect against thrombosis.

Thromboembolic outcomes after use of a four-factor prothrombin complex concentrate for vitamin K antagonist reversal in a real-world setting.

BACKGROUND: A four-factor prothrombin complex concentrate (4F-PCC) was recently licensed in the United States for urgent vitamin K antagonist (VKA) reversal based on two randomized clinical trials. These studies excluded patients at high risk of thrombosis; therefore, the risk of thrombotic complications in unselected patients remains a concern. STUDY DESIGN AND METHODS: This study retrospectively evaluated the incidence of thromboembolic events (TEEs) and death in patients who received 4F-PCC for VKA reversal. The study included 113 consecutive patients who were 18 years of age and older and were administered 4F-PCC for VKA reversal. The incidence of TEE and deaths was evaluated for up to 60 days after PCC administration or until the end of hospitalization, whichever came later. RESULTS: Seven (6.2%) patients developed TEEs and 17 (15%) patients died. PCC administration was probably related to TEE and subsequent death in two (1.8%) patients. Multivariate analysis revealed that a diagnosis of Factor V Leiden or antiphospholipid syndrome was predictive of TEE, and active malignancy was predictive of death. CONCLUSION: This study supports the safety of 4F-PCC for urgent VKA reversal even in unselected patients. The underlying type of hypercoagulable state and the dose of PCC may influence the incidence of TEE.