Category Archives: Hematology

Bleeding Risk with Apixaban vs. Rivaroxaban in Acute Venous Thromboembolism

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“Direct oral anticoagulants, including rivaroxaban and apixaban, are the most frequently prescribed treatments for acute venous thromboembolism. In randomized clinical trials, rivaroxaban at a dose of 15 mg twice daily for 21 days followed by 20 mg daily and apixaban at a dose of 10 mg twice daily for 7 days followed by 5 mg twice daily were noninferior to vitamin K antagonists regarding efficacy (risk of recurrent venous thromboembolism). These trials showed that clinically relevant bleeding, a composite of major bleeding or clinically relevant nonmajor bleeding, occurred in 4.3% of the patients who received apixaban as
compared with 9.7% of those who received vitamin K antagonists9 and in 8.1% of patients who received rivaroxaban as compared with 8.1% of those who received vitamin K antagonists. The difference between apixaban and rivaroxaban therapy regarding the risk of clinically relevant bleeding was hypothesized to be related to heterogeneity in the patient populations and differences in the trial designs. Owing to a lack of trials that have compared rivaroxaban with apixaban regarding the risk of bleeding, clinical practice guidelines do not recommend one anticoagulant over the other.”

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High Prevalence and Mortality Associated with Upper Extremity Deep Venous Thrombosis in Hospitalized Patients at a Tertiary Care Center

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“Venous thromboembolism (VTE), which includes deep venous thrombosis (DVT) and pulmonary embolism (PE), is the third most common cardiovascular disorder with an annual incidence of 0.1%, affecting approximately 5% of the population.1 Upper extremity DVT (UEDVT) has been thought to account for 4e10% of all cases of DVT and may involve the radial, ulnar, brachial, axillary, subclavian, brachiocephalic, or internal jugular veins.
Historically, UEDVT has been considered a relatively benign event. However, as the incidence of UEDVT increases, so do its subsequent complications including PE, venous access difficulties, superior vena cava syndrome, postthrombotic syndrome, and bleeding on therapeutic anticoagulation therapy, suggesting an insufficient understanding and management of UEDVT.
Management guidelines, with the exception of those for thoracic outlet syndrome, are largely
extrapolated from lower extremity DVT (LEDVT) and PE management.”

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Anticoagulant treatment for upper extremity deep vein thrombosis

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“Upper extremity DVT may be complicated by recurrent thrombosis in about 7.5% of cases and by post-thrombotic syndrome in 19.4% of cases, with higher rates of recurrence in patients with cancer-associated thrombosis and of post-thrombotic syndrome in patients with unprovoked thrombosis or related to congenital or anatomical abnormalities. The intensity and duration of anticoagulant treatment need to be balanced against the risk of bleeding
complications, especially in high-risk subgroups like patients with cancer in whom major bleeding events were reported in up to 10%.”

FIGURE 2 Recurrent venous thromboembolism and major bleeding in patients with upper extremity deep vein thrombosis, sorted by the proportion of patients with cancer and an indwelling catheter. Recurrent venous thromboembolism and major bleeding occurring during anticoagulant treatment were considered in the analysis. The vertical line indicates the summary estimate. Gray squares indicate individual study estimates of the proportion, whereas the gray horizontal lines indicate 95% confidence intervals of the individual studies. The diamond indicates the summary estimate with 95% confidence intervals. The horizontal black line refers to the prediction intervals which are displayed numerically under the 95% confidence intervals. CI, confidence interval; ES, estimates; PI, prediction interval
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Venous Thromboembolism Prevention in Emergency General Surgery

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“Venous thromboembolism (VTE) represents the most preventable cause of morbidity and mortality in hospitalized patients, and the Agency for Healthcare Research and Quality (AHRQ) suggests appropriate VTE prophylaxis as a top patient safety practice. The burden of operative and nonoperative emergency general surgery (EGS) is increasing and represents 7% of all hospital admissions in the United States. The reported rate of VTE among patients undergoing EGS is approximately 2.5%. Numerous observational studies, quality improvement studies, randomized clinical trials, reviews, and practice management guidelines are available to guide acute care surgeons in VTE prevention for patients with trauma. However, little guidance is available for the emergency general surgeon. Patients undergoing EGS represent a challenge regarding VTE prevention. Despite the substantial number of annual EGS admissions, little is known about the risk of VTE or the use of mechanical and/or pharmacologic prophylaxis in EGS patients. Furthermore, although guidelines for VTE prophylaxis are available, they are difficult to interpret in the context of admission to an EGS service for an acute condition, particularly when admissions to such services include as many as 70% of patients who do not require operative intervention.”

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Anticoagulant bridging in left-sided mechanical heart valve patients

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“There are two strategies for heparin bridging; administration of intravenous unfractionated heparin (UFH), and subcutaneous low-molecular-weight heparin (LMWH). While both strategies reduce the risk of valve thrombus formation, they have distinct biomedical, financial, and logistical profiles. UFH is administered intravenously according to a nomogram and hence requires peri-procedural hospital admission and continuous monitoring of
activated partial thromboplastin time (aPTT). In contrast, LMWH is administered subcutaneously once or twice daily in an outpatient setting and usually does not require continuous blood monitoring of anti-Xa levels.”

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Management of anticoagulation in patients with human immunodeficiency virus/acquired immunodeficiency virus

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“There is evidence of endothelial dysfunction and a dysregulation of coagulation and fibrinolysis in individuals with HIV. In a study of 109 HIV-infected patients with advanced disease, 10% developed venous thrombosis and 6% developed arterial thrombosis. A variety of laboratory abnormalities were reported, including protein C deficiency, increased factor VIII concentrations, high fibrinogen concentrations, and free protein S deficiency. HIV infection is also associated with an increased D-dimer level, which suggests that HIV infection might be associated with a pro-thrombotic state. HIV disease is theorized to produce a pro-thrombotic state through mechanisms related to activation of the innate and adaptive immune system by low level HIV replication, co-pathogens, and microbial products trans-located from the gastrointestinal tract,”

“The impact of HAART on coagulation is unclear. Protease inhibitors (PI) have been associated with higher fibrinogen levels and lipodystrophy. PIs are also thought to interfere with cytochrome P (CYP) 450 metabolism and regulation of thrombotic proteins. This may
cause a pro-thrombotic state in HIV-infected individuals”

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