Latest medical treatment strategies for venous thromboembolism

Pulmonary embolism with aortic saddle embolism: a rare presentation

We present an uncommon case report of simultaneous pulmonary embolism and aortic saddle embolism. This patient had risk factors for thromboembolic events that included recent surgery for tibia fracture and immobilisation. She underwent emergency bilateral pulmonary artery catheter-directed thrombolysis, followed by bilateral transfemoral embolectomy. The potential benefit of thrombolysis was weighed against the risk of haemorrhage during the surgery after thrombolysis. Treatment guidelines are not well established for such a condition. This case report illustrates our experience and challenges faced in treating this condition.

Obesity Paradox in Patients With Deep Venous Thrombosis

We aimed to investigate the association between obesity and deep venous thrombosis (DVT) in a country with a high prevalence of obesity. This is a retrospective cohort study of patients who presented with DVT between 2008 and 2012. Data were analyzed and compared based on body mass index (BMI), and patients were classified into normal (<25), overweight (≥25 to <30), obese I (30 to <35), obese II (35 to <40), and obese III (≥40). Among 662 patients with DVT, 28% were overweight and 49% were obese. The mean age was 50.3 (16.5) years, and 51% were females. Diabetes mellitus and prior venous thromboembolism were significantly higher among obese patients. History of malignancy was more common in nonobese patients. Protein S and antithrombin III deficiency and hyperhomocysteinemia were more prevalent among morbid obese patients. Also, obese patients had higher incidence of thrombosis in the distal veins ( P = .03). Warfarin use and long-term therapy were more frequent in obese than nonobese. Postthrombotic syndrome was comparable in obese and nonobese groups. Recurrent DVT was higher in obese I ( P < .01), whereas mortality rates were greater in nonobese groups ( P = .001). Malignancy, diabetes mellitus, and common femoral vein involvement were predictors of mortality, whereas BMI ≥30 was the predictor of survival. Cox regression models showed that after adjusting for age, sex, pulmonary embolism, and duration of warfarin treatment, BMI ≥40 had better survival (hazard ratio: 0.177, 95% confidence interval: 0.045-0.691, P = .013). There is a significant association between obesity and DVT. Obese patients have characteristic risk factors and better survival. This obesity paradox needs further studies to assess its clinical and pharmacotherapeutic implications.

Absence of Clinically Relevant Interactions between Rivaroxaban - an Oral, Direct Factor Xa Inhibitor - and Digoxin or Atorvastatin in Healthy Subjects

Objective:

To investigate potential interactions between rivaroxaban, an oral direct Factor Xa inhibitor approved for the management of thromboembolic disorders, and digoxin or atorvastatin.

Methods:

Two randomized, phase 1 clinical trials were undertaken in healthy men to assess pharmacokinetic and pharmacodynamic interactions between rivaroxaban and digoxin or atorvastatin, and the safety of these drug combinations.

Results:

Steady-state rivaroxaban did not affect the pharmacokinetic profile of steady-state digoxin ( n = 17). Digoxin did not significantly influence the pharmacokinetic profile of single-dose rivaroxaban and had minimal effects on rivaroxaban-induced inhibition of Factor Xa activity and prolongation of clotting time. Similarly, steady-state atorvastatin did not affect the pharmacokinetic profile or the pharmacodynamics of rivaroxaban and vice versa ( n = 19). All drugs (alone or in combination) were well tolerated.

Conclusions:

There were no clinically relevant pharmacokinetic or pharmaco - dynamic interactions between rivaroxaban and digoxin, or between rivaroxaban and atorvastatin, suggesting that rivaroxaban can be coadministered with either drug. This study also confirmed that rivaroxaban does not interact with substrates for permeability (P)-glycoprotein alone (digoxin) or P-glycoprotein and cytochrome P450(CYP)3A4 (atorvastatin).

Venous thromboembolism: classification, risk factors, diagnosis, and management

Venous thromboembolism (VTE) is categorised as deep venous thrombosis (DVT) and pulmonary embolism (PE). VTE is associated with high morbidity and causes a huge financial burden on patients, hospitals, and governments. Both acquired and hereditary risks factors contribute to VTE. To diagnose VTE, noninvasive cost-effective diagnostic algorithms including clinical probability assessment and D-dimer measurement may be employed followup by compression ultrasonography for suspected DVT patients and multidetector computed tomography angiography for suspected PE patients. There are pharmacological and mechanical interventions to manage and prevent VTE. The pharmacological approaches mainly target pathways in coagulation cascade nonspecifically: conventional anticoagulants or specifically: new generation of anticoagulants. Excess bleeding is one of the major risk factors for pharmacological interventions. Hence, nonpharmacological or mechanical approaches such as inferior vena cava filters, graduated compression stockings, and intermittent pneumatic compression devices in combination with pharmacological interventions or alone may be a good approach to manage VTE.

Short-term therapy with enoxaparin or unfractionated heparin for venous thromboembolism in hospitalized patients: utilization study and cost-minimization analysis

OBJECTIVES

To evaluate the direct costs of venous thromboembolism (VTE) treatment with unfractionated heparin (UFH) and low-molecular weight heparin, from the institutional perspective.

METHODS

This is a real-world cohort study that included inpatients treated with UFH or enoxaparin for deep venous thromboembolism or pulmonary embolism in a tertiary public hospital. To estimate medical costs we computed the acquisition costs of drugs, supplies for administration, laboratory tests, and hospitalization cost according to the patient ward.

RESULTS

One hundred sixty-seven patients aged 18 to 92 years were studied (50 treated with UFH and 117 with enoxaparin). The median of days in use of heparin was the same in both groups. Activated partial thromboplastin time was monitored in 98% of patients using UFH and 56.4% using enoxaparin. Nonstatistically significant differences were observed between groups in the number of bleeding events (10.0% and 9.4%; P = 1.00); blood transfusion (2.0% and 2.6%; P = 1.00); death (8.0% and 3.4%; P = 0.24); and recurrent VTE, bleeding, or death (20.0% and 14.5%; P = 0.38). Daily mean cost per patient was US$12.63 ± $4.01 for UFH and US$9.87 ± $2.44 for enoxaparin (P < 0.001). The total costs considering the mean time of use were US$88.39 and US$69.11.

CONCLUSION

The treatment of VTE with enoxaparin provided cost savings in a large teaching hospital located in southern Brazil.

Reversible biotinylated oligosaccharides: a new approach for a better management of anticoagulant therapy

OBJECTIVE

In order to obtain a neutralizable antithrombotic, a chimeric molecule (SSR126517E) containing the sequence of a long-lasting antithrombin (AT)-dependent anti-factor Xa pentasaccharide, idraparinux, linked to a biotin molecule was synthesized and tested for anticoagulant and antithrombotic activity.

METHODS

SSR126517E was tested in several models in vitro and in vivo for its pharmacological properties as well as its ability to be neutralized by avidin.

RESULTS

SSR126517E displayed exactly the same properties as idraparinux. In vitro, SSR126517E had a very high affinity for AT (K(d) < 1 nm) and showed a potent anti-FXa effect and inhibition of thrombin generation with IC(50) values similar to those of idraparinux. Ex vivo, after intravenous administration to rats, SSR126517E produced a potent and long-lasting anti-FXa effect comparable to that obtained with idraparinux; as with idraparinux, the subcutaneous bioavailability was 100%. In vivo, SSR126517E was a potent antithrombotic in rat and mouse venous and arterial thrombosis models. Direct comparison in rats showed that SSR126517E was as active as idraparinux, when administered at the same molar dose. Furthermore, injection of avidin triggered the immediate elimination of SSR126517E from the bloodstream, resulting in complete neutralization of the antithrombotic activity of SSR126517E.

CONCLUSIONS

These results show for the first time that coupling an oligosaccharide with biotin has no effect on the former's pharmacokinetic and pharmacologic properties and renders neutralization easy by injection of avidin.