Differentiation of parenteral anticoagulants in the prevention and treatment of venous thromboembolism

Pathophysiology and Management of Hypercoagulation in Infectious Diseases

Numerous systemic infections may have hypercoagulation as one of the complications, which may range from asymptomatic presentation of elevation of biochemical markers of coagulation such as that of fibrin and thrombin generation, to a much severe, symptomatic, life-threatening, disseminated intravascular coagulation (DIC), which results in the formation of thrombi in the microvasculature of various organs. This phenomenon contributes to increase in morbidity and mortality in various infectious diseases. The current review discusses various mechanisms of hypercoagulation during infections such as tissue factor activation, endothelial cell activation, inhibition of physiological anticoagulant pathways, and fibrinolysis inhibition. The review also discusses pathophysiological changes in the coagulation system and its management in the recent pandemic of COVID-19. The article also discusses role of various parenteral and oral anticoagulants in the management of infectious diseases. The review provides clinical data on various anticoagulants used during hospitalization and extended prophylaxis for the management of venous thromboembolism in various infections.

Methodology Because this is a review of published literature and no humans or animals were involved, ethical committee approval was not required and patient consent was not required.

Critically ill patients with edema and ascites may experience subtherapeutic anti-factor Xa levels following abdominal subcutaneous enoxaparin treatment

Enoxaparin is a low molecular weight heparin that is principally prescribed for the treatment and prevention of thromboembolic disorders. In clinical practice, the abdominal site for subcutaneous enoxaparin administration is most preferable because of its simplicity and safety. However, subcutaneous enoxaparin bioavailability in critically ill patients with ascites is uncertain. According to this case report, the bioavailability and absorption of subcutaneous enoxaparin was potentially impaired in a critically ill patient with ascites and local edema based on the therapeutic drug monitoring of anti-factor Xa levels.

The inhibitory effect of tachyplesin I on thrombosis and its mechanisms

Thrombotic diseases are major cause of cardiovascular diseases. This study was designed to investigate the effect of tachyplesin I on platelet aggregation and thrombosis. Platelet aggregation was analysed with a whole blood aggregometer. The mice were employed to investigate the effect of tachyplesin I on thrombosis in vivo. Tachyplesin I inhibited thrombin-induced platelet aggregation in a dose-dependent manner. Furthermore, tachyplesin I significantly reduced thrombosis in carrageenan-induced tail thrombosis model by intraperitoneal injection (0.1, 0.2 or 0.4 mg/kg) or intragastric administration (15, 30 or 60 mg/kg). Tachyplesin I also prolonged the bleeding time (BT) and clotting time (CT). The results revealed that tachyplesin I inhibited platelet aggregation and thrombosis by interfering the PI3K/AKT pathway. Tachyplesin I did not show significantly toxicity to mice under 300 mg/kg via intravenous injection. The results show that tachyplesin I inhibits thrombosis and has low toxicity. It is suggested that tachyplesin I has the potential to develop a new anti-thrombotic drug.

A post hoc analysis of dalteparin versus oral anticoagulant (VKA) therapy for the prevention of recurrent venous thromboembolism (rVTE) in patients with cancer and renal impairment

Venous thromboembolism (VTE) is a common and serious complication in patients with cancer; treatment guidelines recommend extended therapy of ≥6 months with low-molecular-weight heparin (LMWH) for treatment and prevention of recurrent VTE (rVTE) in this population. This post hoc analysis used data from the CLOT study—a phase III, randomized, open-label, controlled study (N = 676)—to compare the efficacy and safety of dalteparin, a LMWH, versus vitamin K antagonist (VKA) for prevention of rVTE in patients with cancer and renal impairment (creatinine clearance <60 ml/min). Overall, 162/676 (24 %) patients had renal impairment at baseline. Patients received subcutaneous dalteparin 200 IU/kg once daily during month 1, followed by 150 IU/kg once daily for months 2–6; or VKA once daily for 6 months, with initial overlapping subcutaneous dalteparin 200 IU/kg once daily for ≥5 days until international normalized ratio was 2.0–3.0 for 2 consecutive days. Endpoints included the rates of rVTE (primary) and bleeding events. Overall, fewer dalteparin-treated patients (2/74 [2.7 %]) experienced ≥1 adjudicated symptomatic rVTE compared with VKA-treated patients (15/88 [17.0 %]; hazard ratio = 0.15 [95 % confidence interval 0.03–0.65]; p = 0.01). Bleeding event rates for both treatments were similar (p = 0.47). In summary, compared with VKA, dalteparin significantly reduced risk of rVTE in patients with cancer and renal impairment (p = 0.01) while exhibiting a comparable safety profile. This analysis supports dosing patients with renal impairment in accordance with patients with normal renal function; however, anti-Xa monitoring could be considered to further support safety in selected patients, particularly those with very severe renal impairment.

Rivaroxaban: An Evaluation of its Cardiovascular Benefit-Risk Profile Across Indications Based on Numbers Needed to Treat or Harm, and on Clinically Meaningful Endpoint Comparisons

The decision to prescribe anticoagulant therapy must consider the balance between reducing the risk of thromboembolic events and increasing the risk of bleeding. Although assessments of net clinical outcomes with oral anticoagulants are not new, this article presents an evaluation of benefit–risk by considering only events of substantial and comparable clinical relevance (i.e., events with serious long-term sequelae likely to have irreversible consequences, including death). This is based on the concept of the number of patients who need to be treated to elicit one beneficial [number needed to treat (NNT)] or harmful [number needed to harm (NNH)] event. The approach is illustrated using data from phase III trials of rivaroxaban, selected because it has the broadest range of approved indications of the novel oral anticoagulants. For example, in the ATLAS ACS 2 TIMI 51 trial of rivaroxaban plus standard antiplatelet therapy following an acute coronary syndrome event, the current analysis demonstrates that 63 patients need to be treated (over 24 months) to prevent one all-cause mortality event compared with placebo (NNT = 63). Conversely, 500 patients need to be treated to cause one additional intracranial hemorrhage (NNH = 500). The most relevant and clinically meaningful assessment of benefit–risk may therefore be achieved by focusing only on events of greatest concern to patients and physicians, namely those with (potentially) long-lasting, severe consequences. Although there are clear limitations to this type of analysis, rivaroxaban appears to demonstrate a broadly favorable benefit–risk profile across multiple clinical indications.

Respiratory review of 2013: pulmonary thromboembolism

Pulmonary embolism (PE), which can originate as a consequence of deep vein thrombosis (DVT), is the most frequent and potentially fatal venous thromboembolic event. Despite the fact that the incidence of venous thromboembolism (VTE) in Asians is lower than that in the Western populations, a recent epidemiologic study demonstrates an increasing incidence of VTE in the Korean population. Anticoagulants, including low molecular weight heparin (LMWH) and vitamin K antagonist (VKAs), have been the main treatments for PE, however, recently new oral anticoagulants (NOACs) were introduced. We will review how well patients with PE can be managed with the existing anticoagulants and NOACs along with the time span of treatment, which still pose some challenges for clinicians.

Oral surgery for patients on anticoagulant therapy: current thoughts on patient management

Minor oral surgical procedures make up a significant part of the daily practice of dentistry. With the increased sophistication of medical technology and medications there is increased likelihood of performing surgery on patients who are being treated for conditions that require some type of anticoagulant therapy. These patients are at an increased risk for perioperative bleeding or thrombotic complications if anticoagulation is discontinued or the dosage is adjusted. Therefore, a fine balance needs to be obtained and adequate preparation of these patients is the key to establishing this balance. This article reviews suggested approaches to the management of such patients.