Rivaroxaban: an oral factor Xa inhibitor

The Impact of Direct Oral Anticoagulant Prophylaxis for Thromboembolism in Thrombophilic Patients Undergoing Abdominoplastic Surgery

Congenital or acquired thrombophilia is observed in 10–15% of the general population; therefore, careful screening is carried out in patients at higher risk of venous thrombo-embolism (VTE). High risk of VTE is a contraindication in patients undergoing abdominoplasty. We evaluated rivaroxaban, an oral Xa inhibitor, with enoxaparin, a subcutaneously low molecular weight heparin (LMWH), in 48 female patients with documented thrombophilia, undergoing thrombo-prophylaxis after abdominoplasty. Patients were stratified into two groups according to thrombo-prophylaxis procedure: enoxaparin Group (n = 28) and rivaroxaban Group (n = 20). Hematologic outcomes were evaluated including VTE and hematoma. No episodes of VTE occurred in both groups; two patients during their course of enoxaparin presented severe hematoma for drainage and hemostasis revision. This study suggests that abdominoplasty, in patients with thrombophilia, in combination with thrombo-prophylaxis can be performed safely. Rivaroxaban was as effective as LMWH for preventing VTE, with only a moderate risk of clinically relevant bleeding. More research is needed to determine the optimal timing and duration of prophylaxis in patients undergoing plastic surgery.

Characteristics of thromboprophylaxis in elderly patients before and after orthopedic hip and knee surgery

Elderly patients with a hip fracture are at significantly higher risk for developing venous thromboembolism (VTE). The incidence of fatal pulmonary embolism (PE) occurs in 2-3% of patients after elective hip and knee surgery and about 6-7% after hip fracture surgery, with a higher risk in men (10,2%) than in women (4,7%). The use of pharmacological prophylaxis significantly reduces the incidence of symptomatic VTE. Pharmacological prophylaxis includes the use of antiplatelet drugs (aspirin), unfractionated heparin (UFH), low molecular weight heparins (LMWH), vitamin K antagonists (VKA), Fondaparinux and direct oral anticoagulants (DOAC). The use of low molecular weight heparins (LMWH) - enoxaparin, represents the gold standard of thromboprophylaxis in orthopedic surgery, and for now, they are the only drugs that are recommended for thromboprophylaxis in hip fracture surgery. Rivaroxaban is used in the prophylaxis of VTE in elective hip and knee surgeries at a fixed dose of 10 mg once daily, and apixaban at a dose of 2,5 mg twice daily in knee arthroplasty for at least 14 days, and after hip arthroplasty for at least 35 days. Early hip fracture surgery as soon as possible, preferably within 24 hours, and no later than 48 hours after admission to the hospital, significantly reduces the morbidity and mortality of elderly patients.

Increased Risk for Thromboembolism After Fontan Surgery: Considerations for Thromboprophylaxis

The Fontan circulation introduces an increased risk of thromboembolism which is associated with substantial mortality and morbidity. Adverse outcomes of thromboembolic complications post-Fontan surgery vary in both nature and severity, ranging from local tissue infarction and pulmonary embolism to Fontan failure and ischemic stroke. Furthermore, recent studies have identified that subclinical stroke is common yet underdiagnosed in Fontan patients. Fontan patients are commonly treated with antiplatelet agents and/or anticoagulants as primary thromboprophylaxis. Optimal thromboprophylaxis management in the Fontan population is still unclear, and clinical consensus remains elusive despite the growing literature on the subject. This perspective will describe the nature of thromboembolism post-Fontan surgery and provide evidence for the use of both current and emerging thromboprophylaxis options for children and adults living with Fontan circulation.

Developing LC-MS/MS methods to quantify rivaroxabanin human plasma and urine: application to therapeuticdrug monitoring

Rivaroxaban is an oral anticoagulant directly inhibiting Factor Xa activity, which is widely used for prophylaxis of thromboembolic disorders and is required for therapeutic drug monitoring (TDM) during therapyfor individual dosage adjustment. Thisstudyaimed at developing a liquidchromatography/tandem mass spectrometry method that was suitable forrivaroxaban TDM in human plasma and urine and exploring the feasibility of urine drug monitoring in medical care. The 3-min run of LC-MS/MS methodswereestablishedby employingan Acquity UPLC BEH C₁₈ (2.1 mm × 50 mm, 1.7 μm) column using gradient elution of 10 mmol/L ammonium acetate containing 0.1% formic acid - 0.1% formic acid acetonitrile as mobile phase at a flow rate of 0.4 mL/min with the calibration range of 0.5 ng/mL-400 ng/mL and 10 ng/mL-10000 ng/mLfor human plasma and urine, respectively. Rivaroxaban wasdetected on a triple quadrupole tandem mass spectrometer with electrospray ionization source in positive ion mode. Themethods showed good linearity within the calibration range. Theprecision and accuracy, matrix effect, extraction recovery and stability inboth human matrices were all validatedand meet the international guideline requirements. These validated methods had been successfullyapplied to support TDMofan aged patient receiving rivaroxaban for therapy.

Pharmacogenomics of Novel Direct Oral Anticoagulants: Newly Identified Genes and Genetic Variants

Direct oral anticoagulants (DOAC) have shown an upward prescribing trend in recent years due to favorable pharmacokinetics and pharmacodynamics without requirement for routine coagulation monitoring. However, recent studies have documented inter-individual variability in plasma drug levels of DOACs. Pharmacogenomics of DOACs is a relatively new area of research. There is a need to understand the role of pharmacogenomics in the interpatient variability of the four most commonly prescribed DOACs, namely dabigatran, rivaroxaban, apixaban, and edoxaban. We performed an extensive search of recently published research articles including clinical trials and in-vitro studies in PubMed, particularly those focusing on genetic loci, single nucleotide polymorphisms (SNPs), and DNA polymorphisms, and their effect on inter-individual variation of DOACs. Additionally, we also focused on commonly associated drug-drug interactions of DOACs. CES1 and ABCB1 SNPs are the most common documented genetic variants that contribute to alteration in peak and trough levels of dabigatran with demonstrated clinical impact. ABCB1 SNPs are implicated in alteration of plasma drug levels of rivaroxaban and apixaban. Studies conducted with factor Xa, ABCB1, SLCOB1, CYP2C9, and VKORC1 genetic variants did not reveal any significant association with plasma drug levels of edoxaban. Pharmacokinetic drug-drug interactions of dabigatran are mainly mediated by p-glycoprotein. Strong inhibitors and inducers of CYP3A4 and p-glycoprotein should be avoided in patients treated with rivaroxaban, apixaban, and edoxaban. We conclude that some of the inter-individual variability of DOACs can be attributed to alteration of genetic variants of gene loci and drug-drug interactions. Future research should be focused on exploring new genetic variants, their effect, and molecular mechanisms that contribute to alteration of plasma levels of DOACs.

The management of livedoid vasculopathy focused on direct oral anticoagulants (DOACs): four case reports successfully treated with rivaroxaban

Livedoid vasculopathy (LV) is a thrombotic skin disease characterized by episodic painful ulcerations of the distal aspects of the legs. Its healing process typically leaves small porcelain-white scars called atrophie blanche as a result of the occlusion of cutaneous microcirculation. The main goals of the treatment are pain management and the prevention of ulceration and of progressive scarring in the malleolar area. The therapeutic management is still a challenge, however, and most treatments were based on anecdotal off-label protocols. Over such context, direct oral anticoagulants (DOACS) arise as a potential treatment for this disease. This class of medications became an alternative from initial large studies applied on different pathologic scenarios regarding thromboembolic events. In that line, recent case series using DOACS, including rivaroxaban, started to emerge in the literature related to LV and reported successful prevention of cutaneous infarctions and ulcerations, providing physicians with a new promising alternative. The current report describes four cases of long-term recalcitrant LV, in which rivaroxaban monotherapy effectively reduced pain and cutaneous ulcerations in a few weeks of treatment without relevant side effects. The authors also review therapy management of the disease, focused on DOACS, and suggest a step-by-step approach to treat these patients, taking into consideration different resource profiles of each level of local health centers, the gravity of the cases, and risks/benefits for patients.

Rivaroxaban prescribing in a Saudi tertiary care teaching hospital

Purpose

This drug utilization review (DUR) aimed to describe the use of rivaroxaban in a tertiary care teaching hospital and to audit the hospital physicians’ prescribing practice.

Methods

This study reviewed rivaroxaban prescriptions for patients admitted to a tertiary care teaching hospital in Riyadh, Saudi Arabia, between October 1, 2016 and January 15, 2017. It included all in-patients who received at least one dose of rivaroxaban, using data from the hospital’s health information system (HIS). Appropriateness of prescribing was evaluated based on documented indication, dosing according to the patient’s renal function for each approved indication, and restriction policy as per hospital department.

Results

During the study period, a total of 343 rivaroxaban prescriptions for 322 patients were identified. Overall, more than 56% of rivaroxaban prescriptions met at least one inappropriate criterion. Inappropriate dosing per patient’s creatinine clearance (CrCl) was recognized in 42% of rivaroxaban prescriptions with the majority of these prescriptions issued for lower doses in 82.9% of prescriptions and non-approved indications identified in 14% of rivaroxaban prescriptions.

Conclusions

The introduction of oral rivaroxaban represents a paradigm shift in anticoagulation management. Future longer, larger multi-center research is needed to identify the most effective interventions to enhance rivaroxaban knowledge translation and reduce the likelihood of inappropriate rivaroxaban prescribing and associated economic and side effects sequelae.

FXa inhibition by rivaroxaban modifies mechanisms associated with the pathogenesis of human abdominal aortic aneurysms

AIMS

To evaluate if rivaroxaban, an oral factor Xa (FXa) inhibitor, could modify the expression in vitro of inflammatory and oxidative stress biomarkers in abdominal aortic aneurysmal (AAA) sites showing intraluminal thrombus.

METHODS

AAA sites with intraluminal mural thrombus were obtained from six patients undergoing elective AAA repair. In addition, control abdominal aortic samples were obtained from six organ donors. AAA sites were incubated in the presence and absence of 50 nmol l^-1 rivaroxaban.

RESULTS

AAA sites showing thrombus demonstrated higher content of FXa than control. Interleukin-6 levels released from AAA [Control: median: 23.45 (interquartile range: 16.17-37.15) vs. AAA: median: 153.07 (interquartile range: 100.80-210.69) pg ml^-1  mg tissue^-1 , P < 0.05] and the expression levels of nitric oxide synthase 2 were significantly higher in AAA than in control. The protein expression level of NADPH oxidase subunits gp67-and gp91-phox, but did not gp47-phox, were also significantly higher in the AAA sites than in control. Addition of rivaroxaban to AAA sites explants significantly reduced the release of interleukin-6 [median: 51.61 (interquartile range: 30.87-74.03) pg ml^-1  mg tissue^-1 , P < 0.05 with respect to AAA alone] and the content of nitric oxide synthase 2, gp67 and gp91-phox NADPH subunits. The content of matrix metallopeptidase 9 was significantly higher in the AAA sites as compared to control. Rivaroxaban also reduced matrix metallopeptidase 9 content in AAA sites to similar levels to control.

CONCLUSIONS

FXa inhibition by rivaroxaban exerted anti-inflammatory and antioxidative stress properties in human AAA sites, suggesting a role of FXa in these mechanisms associated with the pathogenesis of AAA.

Determination of rivaroxaban in patient's plasma samples by anti-Xa chromogenic test associated to High Performance Liquid Chromatography tandem Mass Spectrometry (HPLC-MS/MS)

Rivaroxaban is an oral direct factor Xa inhibitor, therapeutically indicated in the treatment of thromboembolic diseases. As other new oral anticoagulants, routine monitoring of rivaroxaban is not necessary, but important in some clinical circumstances. In our study a high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was validated to measure rivaroxaban plasmatic concentration. Our method used a simple sample preparation, protein precipitation, and a fast chromatographic run. It was developed a precise and accurate method, with a linear range from 2 to 500 ng/mL, and a lower limit of quantification of 4 pg on column. The new method was compared to a reference method (anti-factor Xa activity) and both presented a good correlation (r = 0.98, p < 0.001). In addition, we validated hemolytic, icteric or lipemic plasma samples for rivaroxaban measurement by HPLC-MS/MS without interferences. The chromogenic and HPLC-MS/MS methods were highly correlated and should be used as clinical tools for drug monitoring. The method was applied successfully in a group of 49 real-life patients, which allowed an accurate determination of rivaroxaban in peak and trough levels.

Retrospective evaluation of the incidence and prognostic significance of spontaneous echocardiographic contrast in relation to cardiac disease and congestive heart failure in cats: 725 cases (2006-2011)

OBJECTIVE

To determine whether the presence of spontaneous echocardiographic contrast (SEC) in cats with cardiomyopathy is associated with increased mortality. To establish whether specific types of cardiomyopathy are more often associated with SEC in an attempt to provide a risk-stratification scheme for cats with increased risk of thromboembolic events.

DESIGN

Retrospective study 2006-2011.

SETTING

Tertiary referral and teaching hospital.

ANIMALS

Seven hundred twenty-five client-owned cats undergoing echocardiographic evaluation.

MEASUREMENTS AND MAIN RESULTS

Patient characteristics, including age, breed, clinical signs, type of cardiovascular disease, presence of SEC, and survival time were recorded. Thyroxine, HCT, and blood pressure were recorded when available. Among cats diagnosed with cardiac abnormalities based on echocardiographic findings, those with SEC were at significantly increased risk of death as compared to those without SEC. Cats with dilated cardiomyopathy, unclassified cardiomyopathy, and hypertrophic cardiomyopathy were significantly more likely to have SEC compared to cats with other types of cardiac disease.

CONCLUSIONS

Cats with cardiomyopathy and SEC have an increased risk of death compared to cats without SEC, although other previously identified factors such as the presence of congestive heart failure and increased left atrium to aorta ratio remain important determinants of mortality. Cats with hypertrophic cardiomyopathy, unclassified cardiomyopathy, and dilated cardiomyopathy may benefit from anticoagulant therapy due to the increased risk of SEC in these subpopulations.

A New Generation of Antiplatelet, and Anticoagulant Medication and the Implications for the Dental Surgeon

The management of dental patients taking either antiplatelet medication, anticoagulant medication or both has been well established in the previous literature. Recently, new generations of drugs have emerged which are becoming increasingly common, including direct thrombin inhibitors, factor X inhibitors and a new class of oral thienopyridines. The implications of these drugs for the dental surgeon are not yet fully known. Awareness remains low and there is very little information available within the literature on safe use during surgery. This review paper aims to provide some guidance for dental practitioners performing invasive procedures. CPD/CLINICAL RELEVANCE: A new generation of anticoagulant and antiplatelet drugs have serious implications for patients undergoing surgery and their use is increasing.

Retracted: Spontaneous rectus sheath haematoma associated with rivaroxaban treatment

http://onlinelibrary.wiley.com/doi/10.1111/jcpt.12228/pdf The above article, published online on 10 November 2014 in Wiley Online Library (wileyonlinelibrary.com), has been retracted by agreement between the authors, the journal Editor in Chief, A. Li Wan Po, and John Wiley & Sons Ltd. The retraction has been agreed because, unknown to the authors, another group published a similar study based on the same material in the Indian Journal of Pharmacology: Kocayigit I, Can Y, Sahinkus S, et al. Spontaneous rectus sheath haematoma during rivaroxaban therapy. Indian Journal of Pharmacology. 2014;46(3):339-340. doi:10.4103/0253-7613.132193.

A cross-country comparison of rivaroxaban spontaneous adverse event reports and concomitant medicine use with the potential to increase the risk of harm

BACKGROUND

Concerns with the safety profiles of the newer anticoagulants have been raised because of differences in treatment populations between pre-marketing studies (randomized controlled trials) and clinical practice. Little is known about the potential safety issues and the reporting in spontaneous adverse event databases associated with rivaroxaban.

OBJECTIVES

To analyse spontaneous adverse event reports associated with the oral anticoagulant rivaroxaban from Australia, Canada and the USA; and to examine concomitant medicine use that may increase the risk of adverse events.

METHODS

Spontaneous adverse event report databases from Australia, Canada and the USA were examined for all reports of adverse events associated with rivaroxaban and concomitant medicines from 1 August 2005 to 31 March 2013. Disproportionality analysis (the proportional reporting ratio [PRR] and reporting odds ratio [ROR]) was conducted for quantitative detection of signals, using the US database.

RESULTS

There were 244 spontaneous adverse event reports associated with rivaroxaban from Australia, 536 from Canada and 1,638 from the USA. Reporting of haemorrhage (any type) was common, ranging from 30.7% for Australia to 37.5% for Canada. Gastrointestinal haemorrhage was the most commonly reported haemorrhage, accounting for 13.9% of Australian, 16.4% of Canadian and 11.1% of US adverse event reports. Positive signals were confirmed in the US data (haemorrhage [any type] PRR 11.93, χ (2) 4,414.78 and ROR 13.41, 95% confidence interval [CI] 12.13-14.81; gastrointestinal haemorrhage PRR 12.52, χ (2) 2,018.48 and ROR 13.15, 95% CI 11.36-15.21). Reporting of concomitant use of medicines with the potential to increase bleeding risk ranged from 63.7% in Australia to 89.2% in Canada.

CONCLUSION

A large proportion of adverse event reports for rivaroxaban were associated with use of concomitant medicines, which may have increased the risk of adverse events-in particular, haemorrhage. Increased awareness of a patient's comorbidity and associated medicine use is needed when rivaroxaban is used in clinical practice.

Rivaroxaban-associated Delayed Spontaneous Periprosthetic Hematoma

The authors present a case of spontaneous delayed periprosthetic breast haematoma in a woman taking Rivaroxaban.

Tranexamic Acid Tamponade to Control Postoperative Surgical Hemorrhage

When preparing for oral surgery, patients taking anticoagulants usually should not discontinue their medication because of the risk of a thromboembolic event. The therapeutic effect of many anticoagulants is not readily measured, so preoperatively, the surgeon cannot know the true risk for postoperative hemorrhage. The risk of a thromboembolic event usually outweighs the concerns of controlling postoperative hemorrhage. Hemophilia patients are also at risk for postoperative bleeding. Single extractions probably do not pose a serious risk for postoperative hemorrhage. However, when a mucogingival flap is raised in these patients, there may be prolonged bleeding. Surgical sponges saturated with aqueous tranexamic acid solution and compressed onto the bleeding site with biting pressure may stop bleeding. Bleeding was stopped in the case example presented here after three 10-minute compressions over 30 minutes in a patient taking aspirin and clopidogrel for a previous thromboembolic event and a metal coronary stent. The clot formed is very fragile and is prone to bleeding, so it should not be disturbed. This technique needs to be studied for efficacy.