Evidence-based management of anticoagulant therapy: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines

Risk of symptomatic venous thromboembolism associated with flying in the early postoperative period following elective total hip and knee arthroplasty

Air travel and total joint arthroplasty (TJA) are both risk factors for venous thromboembolism (VTE). Patients are counseled against flying after surgery, however the basis for this recommendation has not been investigated and may be unfounded. A retrospective cohort of 1465 consecutive TJA patients was divided into a study population of 220 patients (15.0%) who flew home at a mean of 2.9 days after surgery (range, 1-10 days) and a control population of 1245 patients (85.0%) who did not fly. We found no differences in the rate of deep vein thrombosis, pulmonary embolism, or overall VTE between the groups, and incidence of all events was low in both groups and comparable with published data. Allowing air travel after TJA appears to be a safe practice.

Controversies regarding the new oral anticoagulants for stroke prevention in patients with atrial fibrillation

Increasing use of the new oral anticoagulants (NOACs) – dabigatran, rivaroxaban, and apixaban – has prompted considerable discussion in the medical community even as warfarin remains the mainstay of therapy. This article raises 10 controversial issues regarding the use of NOACs for stroke prevention in patients with atrial fibrillation, and offers a review of the latest available evidence. We provide a brief overview of the mechanism and dosing of these drugs, as well as a summary of the key clinical trials that have brought them into the spotlight. Comparative considerations relative to warfarin such as NOAC safety, efficacy, bleeding risk, reversibility, drug-transitioning and use in patients well controlled on warfarin are addressed. Use in select populations such as the elderly, those with coronary disease, renal impairment, or on multiple anti-platelet drugs is also discussed. Finally, we consider such specific issues as comparative efficacy, off-label use, cost, rebound and management during events. Ultimately, the rise of the NOACs to mainstream use will depend on further data and clinical experience amongst the medical community.

Personalized pharmacogenomics: predicting efficacy and adverse drug reactions

Drug response varies between individuals owing to disease heterogeneity, environmental factors, and genetic factors. Genetic factors can affect both the pharmacokinetics and pharmacodynamics of a drug, leading to changes in local and systemic drug exposure and/or changes in the function of the drug target, altering drug response. Several pharmacogenetic biomarkers are already utilized in clinical practice and have been shown to improve clinical outcomes. However, a large number of other biomarkers have never made it beyond the discovery stage. Concerted effort is needed to improve the translation of pharmacogenetic biomarkers into clinical practice, and this will involve the use of standardized phenotyping and genotyping strategies, collaborative work, multidisciplinary approaches to identifying and replicating associations, and cooperation with industry to facilitate translation and commercialization. Acceptance of these approaches by clinicians, regulators, patients, and the public will be important in determining future success.

Comparison of warfarin therapy clinical outcomes following implementation of an automated mobile phone-based critical laboratory value text alert system

BACKGROUND

Computerized alert and reminder systems have been widely accepted and applied to various patient care settings, with increasing numbers of clinical laboratories communicating critical laboratory test values to professionals via either manual notification or automated alerting systems/computerized reminders. Warfarin, an oral anticoagulant, exhibits narrow therapeutic range between treatment response and adverse events. It requires close monitoring of prothrombin time (PT)/international normalized ratio (INR) to ensure patient safety. This study was aimed to evaluate clinical outcomes of patients on warfarin therapy following implementation of a Personal Handy-phone System-based (PHS) alert system capable of generating and delivering text messages to communicate critical PT/INR laboratory results to practitioners' mobile phones in a large tertiary teaching hospital.

METHODS

A retrospective analysis was performed comparing patient clinical outcomes and physician prescribing behavior following conversion from a manual laboratory result alert system to an automated system. Clinical outcomes and practitioner responses to both alert systems were compared. Complications to warfarin therapy, warfarin utilization, and PT/INR results were evaluated for both systems, as well as clinician time to read alert messages, time to warfarin therapy modification, and monitoring frequency.

RESULTS

No significant differences were detected in major hemorrhage and thromboembolism, warfarin prescribing patterns, PT/INR results, warfarin therapy modification, or monitoring frequency following implementation of the PHS text alert system. In both study periods, approximately 80% of critical results led to warfarin discontinuation or dose reduction. Senior physicians' follow-up response time to critical results was significantly decreased in the PHS alert study period (46.3% responded within 1 day) compared to the manual notification study period (24.7%; P = 0.015). No difference in follow-up response time was detected for junior physicians.

CONCLUSIONS

Implementation of an automated PHS-based text alert system did not adversely impact clinical or safety outcomes of patients on warfarin therapy. Approximately 80% immediate recognition of text alerts was achieved. The potential benefits of an automated PHS alert for senior physicians were demonstrated.

Guideline-concordant administration of prothrombin complex concentrate and vitamin K is associated with decreased mortality in patients with severe bleeding under vitamin K antagonist treatment (EPAHK study)

Introduction

In vitamin K antagonist (VKA)-treated patients with severe hemorrhage, guidelines recommend prompt VKA reversal with prothrombin complex concentrate (PCC) and vitamin K. The aim of this observational cohort study was to evaluate the impact of guideline concordant administration of PCC and vitamin K on seven-day mortality.

Methods

Data from consecutive patients treated with PCC were prospectively collected in 44 emergency departments. Type of hemorrhage, coagulation parameters, type of treatment and seven-day mortality mortality were recorded. Guideline-concordant administration of PCC and vitamin K (GC-PCC-K) were defined by at least 20 IU/kg factor IX equivalent PCC and at least 5 mg of vitamin K performed within a predefined time frame of eight hours after admission. Multivariate analysis was used to assess the effect of appropriate reversal on seven-day mortality in all patients and in those with intracranial hemorrhage (ICH).

Results

Data from 822 VKA-treated patients with severe hemorrhage were collected over 14 months. Bleeding was gastrointestinal (32%), intracranial (32%), muscular (13%), and “other” (23%). In the whole cohort, seven-day mortality was 13% and 33% in patients with ICH. GC-PCC-K was performed in 38% of all patients and 44% of ICH patients. Multivariate analysis showed a two-fold decrease in seven-day mortality in patients with GC-PCC-K (odds ratio (OR) = 2.15 (1.20 to 3.88); P = 0.011); this mortality reduction was also observed when only ICH was considered (OR = 3.23 (1.53 to 6.79); P = 0.002).

Conclusions

Guideline-concordant VKA reversal with PCC and vitamin K within eight hours after admission was associated with a significant decrease in seven-day mortality.

The role of prothrombin complex concentrates in reversal of target specific anticoagulants

Over the past several years a new era for patients requiring anticoagulation has arrived. The approval of new target specific oral anticoagulants offers practitioners several advantages over traditionally used vitamin K antagonist agents including predictable pharmacokinetics, rapid onset of action, comparable efficacy and safety, all without the need for routine monitoring. Despite these benefits, hemorrhagic complicates are inevitable with any anticoagulation treatment. One of the major disadvantages of the new oral anticoagulants is lack of specific antidotes or reversal agents for patients with serious bleeding or need for urgent surgery. As use of the new target specific oral anticoagulants continues to increase, practitioners will need to understand both the pharmacodynamics and pharmacokinetic properties of the agents, as well as, the available literature with use of non-specific therapies to reverse anticoagulation. Four factor prothrombin complex concentrates have been available for several years in Europe, and recently became available in the United States with approval of Kcentra. These products have shown efficacy in reversing anticoagulation from vitamin K antagonists, however their usefulness with the new target specific oral anticoagulants is poorly understood. This article will review the properties of dabigatran, rivaroxaban and apixaban, as well as the limited literature available on the effectiveness of prothrombin complex concentrates in reversal of their anticoagulant effects. Additional studies are needed to more accurately define the role of prothrombin complex concentrates in patients with life threatening bleeding or who require emergent surgery, as current data is both limited and conflicting.

Acquired Thrombophilia

Acquired thrombophilia is associated with an increased risk of venous thromboembolism (VTE). Antiphospholipid syndrome (APS) is the most prevalent acquired thrombophilia and is associated with both venous and arterial thromboses. Human immunodeficiency virus (HIV) is another form of acquired thrombophilia. Risk factors associated with VTE in this population include those related to the disease itself, host factors, and the pharmacotherapy for HIV. A significant proportion of VTE events occur in patients with malignancies. There is an increase in mortality associated with patients having cancer who experience VTE when compared to patients having cancer without VTE. Combination oral contraceptive (COC) use infers risk of thromboembolic events. The risk is dependent upon the presence of an underlying inherited thrombophilia, the estrogen dose, and generation of progestin. Patients at highest risk of VTE include those receiving high-dose estrogen and fourth-generation, progesterone-containing contraceptives. With the exception of APS, thrombophilia status does not alter the acute treatment of an initial VTE in nonpregnant patients.

Inherited Thrombophilia

Thrombophilia alters normal hemostasis, shifting the balance in favor of thrombus formation. Inherited conditions include factor V Leiden (FVL), prothrombin G20210A mutation, deficiencies in natural anticoagulants (antithrombin [AT], protein C, and protein S), hyperhomocysteinemia, and elevations in clotting factors (factors VIII and XI). Although FVL and prothrombin mutation are common disorders, deficiencies in the natural anticoagulants are rare. The risk of initial thrombosis conferred by inherited thrombophilia varies with the highest risk in those homozygous for either FVL or prothrombin mutation, or with AT deficiency. In the nonpregnant patient, the presence of a thrombophilia does not affect treatment of an acute event. Although vitamin B supplementation has been shown to decrease the levels of homocysteine, the treatment has failed to show a benefit in thrombus prevention and is therefore not recommended.

Comparison of 3-Factor Prothrombin Complex Concentrate and Low-Dose Recombinant Factor VIIa for Warfarin Reversal

Introduction

Prothrombin complex concentrate (PCC) and recombinant Factor VIIa (rFVIIa) have been used for emergent reversal of warfarin anticoagulation. Few clinical studies have compared these agents in warfarin reversal. We compared warfarin reversal in patients who received either 3 factor PCC (PCC3) or low-dose rFVIIa (LDrFVIIa) for reversal of warfarin anticoagulation.

Methods

Data were collected from medical charts of patients who received at least one dose of PCC3 (20 units/kg) or LDrFVIIa (1000 or 1200 mcg) for emergent warfarin reversal from August 2007 to October 2011. The primary end-points were achievement of an INR 1.5 or less for efficacy and thromboembolic events for safety.

Results

Seventy-four PCC3 and 32 LDrFVIIa patients were analyzed. Baseline demographics, reason for warfarin reversal, and initial INR were equivalent. There was no difference in the use of vitamin K or fresh frozen plasma. More LDrFVIIa patients achieved an INR of 1.5 or less (71.9% vs. 33.8%, p =0.001). The follow-up INR was lower after LDrFVIIa (1.25 vs. 1.75, p < 0.05) and the percent change in INR was larger after LDrFVIIa (54.1% vs. 38.8%, p = 0.002). There was no difference in the number of thromboembolic events (2 LDrFVIIa vs. 5 PCC3, p = 1.00), mortality, length of hospital stay, or cost.

Conclusions

Based on achieving a goal INR of 1.5 or less, LDrFVIIa was more likely than PCC3 to reverse warfarin anticoagulation. Thromboembolic events were equivalent in patients receiving PCC3 and LDrFVIIa.

Comparison between the conventional method and a portable device for determination of INR

CONTEXT: Anticoagulation with warfarin is considered the appropriate treatment for venous thromboembolism and other thrombotic pathologies. Regular INR control is required for dosage adjustment and therapeutic control. Use of portable monitoring systems optimizes management of these patients. OBJECTIVE: To compare INR measurements taken using the portable Coaguchek XS system in capillary blood with the standard laboratory method using venous blood. METHOD: Fifty-two samples each of venous and capillary blood were collected from nineteen patients on warfarin, who had been admitted to the Hospital da Beneficência Portuguesa de São Paulo, and analyzed using the conventional method and the Coaguchek XS system, respectively. RESULTS: Spearman's correlation coefficient ® for the overall performance of the two methods was 0.978 (p<0.0001; 95%CI 0.961-0.988). The Kappa measure of agreement for all patients was 76.8% (p<0.001; IC: 95% 0.975-0.561). Mean INR according to the Coaguchek XS system underestimated the values provided by the conventional method by -0.01 INR points, with a standard error of 0.342. Results for INR values greater than 3.5 were satisfactory with a correlation coefficient of 0.71, but without statistical significance (p>0.714). CONCLUSIONS: The Coaguchek XS system can be used to monitor prothrombin time in patients on oral anticoagulants, provided INR values greater than 3.5 are confirmed using the conventional laboratory method.

Treatment of submassive pulmonary embolism with tenecteplase or placebo: cardiopulmonary outcomes at 3 months: multicenter double-blind, placebo-controlled randomized trial

BACKGROUND

Acute pulmonary embolism (PE) can worsen quality of life due to persistent dyspnea or exercise intolerance.

OBJECTIVE

Test if tenecteplase increases the probability of a favorable composite patient-oriented outcome after submassive PE.

METHODS

Normotensive patients with PE and right ventricular (RV) strain (by echocardiography or biomarkers) were enrolled from eight hospitals. All patients received low-molecular-weight heparin followed by random assignment to either a single weight-based bolus of tenecteplase or placebo, administered in a double-blinded fashion. The primary composite outcome included: (i) death, circulatory shock, intubation or major bleeding within 5 days or (ii) recurrent PE, poor functional capacity (RV dysfunction with either dyspnea at rest or exercise intolerance) or an SF36(®) Physical Component Summary (PCS) score < 30 at 90-day follow-up.

RESULTS

Eighty-three patients were randomized; 40 to tenecteplase and 43 to placebo. The trial was terminated prematurely. Within 5 days, adverse outcomes occurred in three placebo-treated patients (death in one and intubation in two) and one tenecteplase-treated patient (fatal intracranial hemorrhage). At 90 days, adverse outcomes occurred in 13 unique placebo-treated patients and five unique tenecteplase-treated patients Thus, 16 (37%) placebo-treated and six (15%) tenecteplase-treated patients had at least one adverse outcome (exact two-sided P = 0.017).

CONCLUSIONS

Treatment of patients with submassive pulmonary embolism with tenecteplase was associated with increased probability of a favorable composite outcome.

Health system capacity and infrastructure for adopting innovations to care for patients with venous thromboembolic disease

BACKGROUND

Diagnosis and treatment for venous thromboembolic disease (VTE) have evolved considerably through diagnostic and therapeutic innovations. Despite their considerable potential for enhancing care, however, the extent to which these innovations are being adopted in usual practice is unknown. We documented the infrastructure available in hospitals and health regions across Canada for provision of optimal diagnosis and therapy for VTE disease.

METHODS

Over the period January 2008 through October 2009, we studied health system infrastructure for care of VTE disease in Canada's 10 provinces and 3 territories and all 94 health regions therein. We interviewed health system managers and/or clinical leaders from all 658 acute care hospitals in Canada and documented key elements of health system infrastructure at the hospital level for these institutions.

RESULTS

There was considerable variation across Canada in the availability of key infrastructure for the diagnosis and management of VTE disease. Provinces with higher populations tended to have a large proportion of hospitals with capability to measure d-dimer levels, whereas less populated provinces were more likely to send samples to centralized analysis facilities for d-dimer testing. All provinces and territories had some facilities offering advanced diagnostic imaging, but the number of institutions and the availability of imaging were highly variable (with the proportion offering at least limited availability ranging from 0% to 90%). Only 6 provinces had regions with availability of dedicated early and/or long-term outpatient clinics for VTE disease.

CONCLUSIONS

Infrastructure in Canada for optimal care of patients with VTE disease was suboptimal during the study period and was not entirely in step with the evidence. Such shortfalls in health system infrastructure limit the extent to which health care providers can deliver optimal, evidence-based care to their patients. Nationwide evaluations of health system infrastructure such as this one should be undertaken internationally to better characterize quality of care and potential for improvement.

Impact of CYP2C9 polymorphisms on the vulnerability to pharmacokinetic drug-drug interactions during acenocoumarol treatment

AIM

The objective of this study was to investigate the impact of CYP2C9 polymorphisms and drug-drug interactions on the risk of overanticoagulation in patients treated with acenocoumarol, a vitamin K antagonist.

MATERIALS & METHODS

A prospective observational study was performed on patients starting acenocoumarol (n = 115). CYP2C9 genotypes were assessed. Data on International Normalized Ratio, comedications and doses of acenocoumarol were collected during the first 35 days of therapy. Overanticoagulation was defined as the occurrence of at least one International Normalized Ratio ≥4.

RESULTS

The presence of a CYP2C9 inhibitor or a CYP2C9 polymorphisms statistically increased the risk of overanticoagulation (hazard ratio [HR]: 2.8, p < 0.001 and HR: 1.7, p = 0.04, respectively). The presence of CYP2C9 polymorphisms almost tripled the risk of overanticoagulation (HR: 2.91, p = 0.01) in the presence of a clinically significant drug-drug interaction.

CONCLUSION

These findings support the fact that CYP2C9 genotyping could be useful to identify patients requiring closer monitoring, especially when a drug-drug interaction is expected.

Pharmacogenetics in clinical practice: how far have we come and where are we going?

Recent years have seen great advances in our understanding of genetic contributors to drug response. Drug discovery and development around targeted genetic (somatic) mutations has led to a number of new drugs with genetic indications, particularly for the treatment of cancers. Our knowledge of genetic contributors to variable drug response for existing drugs has also expanded dramatically, such that the evidence now supports clinical use of genetic data to guide treatment in some situations, and across a variety of therapeutic areas. Clinical implementation of pharmacogenetics has seen substantial growth in recent years and groups are working to identify the barriers and best practices for pharmacogenetic-guided treatment. The advances and challenges in these areas are described and predictions about future use of genetics in drug therapy are discussed.

Measuring the anticoagulant effects of target specific oral anticoagulants-reasons, methods and current limitations

To simplify and optimize oral anticoagulation, new target-specific oral anticoagulants (TSOAs) have been developed. The direct thrombin-inhibitor dabigatran and the direct factor Xa inhibitors rivaroxaban, apixaban and edoxaban are the first such compounds to receive approval in certain countries for various indications. Due to the predictable pharmacokinetic and pharmacodynamic profiles of these drugs, routine monitoring of patients receiving TSOA therapy has not been considered necessary. However, it has now been realized that in routine clinical settings, there are several situations where it may be prudent to assess the level of TSOA anticoagulation. Several studies evaluating the influence of TSOAs on various coagulation assays have been performed to identify systems that can be used to monitor these drugs. With a particular focus on dabigatran and rivaroxaban, we will describe and discuss the potential of several methods for measuring the anticoagulant effect of TSOAs, as well as their methodological limitations and the restrictions in transferring their results into clinical context.

Reversal of target-specific oral anticoagulants

The target-specific oral anticoagulants represent the first new oral anti-thrombotic therapy in over 50 years and have the potential to make therapy easier and hence more accessible to many patients. Like any new therapy, the potential benefits must be weighed against the potential challenges and one of the most concerning aspects of the new target-specific oral anticoagulants is the lack of a proven method to reverse their effect. Unlike the vitamin K antagonist, i.e. warfarin, there is no specific antidote for these medications. This paper will review the limited data on the use of non-specific therapies to reverse anticoagulation for the new agents. We hope to prepare clinicians who are faced with a patient who has serious bleeding or needs emergent surgery while taking dabigatran, rivaroxaban or apixaban.

Review of the American College of Chest Physicians 2012 Guidelines for Anticoagulation Therapy and Prevention of Thrombosis

The eighth edition (AT8) of the American College of Chest Physicians (ACCP) Antithrombotic Therapy and Prevention of Thrombosis Guideline, published in June 2008, was a comprehensive presentation of primary studies and detailed discussions of rationale for recommendations. This resulted in an approximately 900-page Chest Supplement publication. Updating the guidelines in a succinct fashion posed a formidable challenge for the ninth edition (AT9), published in February 2012. The strategy adopted for AT9 was to publish an Executive Summary of the recommendations in a 50-page document in the Chest supplement highlighting the changes, with online publication of the full version. Major innovative changes include a recognition of the value of estimating the risk reductions in symptomatic, as opposed to asymptomatic (venographically), detected venous thrombosis, using nonconflicted methodologists as topic editors, new insights into evidence, and increasing emphasis on what is known about patients' values and preferences that have served to improve this edition of the guidelines. This review provides a summary of the updates of the guidelines for anticoagulation therapy and prevention of thrombosis. The AT9 recommendations are presented with, if included, the AT8 recommendations in parenthesis for comparison purposes.

Management of postoperative complications: anemia

Anemia is extremely common following hip fracture. Consistent data from randomized trials show that transfusion of less blood, with a transfusion threshold around 8 g/dL hemoglobin concentration, is preferable to a traditional threshold of 10 g/dL. Adoption of a lower threshold leads to at least equivalent clinical outcomes, with much less exposure to transfusion costs and risks. The most common complication of transfusion is circulatory overload. Future research may elucidate the optimal transfusion threshold for these elderly patients and address the specific needs of subgroups of patients, including those with acute coronary syndrome or chronic kidney disease.

Evaluation of thromboprophylaxis in medium-sized general hospital

CONTEXT: Deep vein thrombosis (DVT) is a serious, common disease whose complications include pulmonary thromboembolism (PTE) and postthrombotic syndrome. The importance and benefits of correct and effective pharmacological prophylaxis for DVT are well documented. OBJECTIVES: The aims of this study were to evaluate adequacy of prophylaxis for DVT and PTE at the Santa Casa de Misericórdia de Ponta Grossa (SCMPG), Paraná, Brazil, and determine risk stratification for patients hospitalized in this institution. METHODS: A cohort study was conducted to assess DVT prophylaxis of patients hospitalized on May 15th, 2009. The study population consisted of a sample of 104 patients, subdivided into clinical and surgical groups and stratified into different specialties. Correct use of DVT prophylaxis was evaluated according to recommendations published by The Brazilian Society for Angiology and Vascular Surgery and took into account prophylactic methods specified explicitly in information found in each patient's medical chart. RESULTS: Of the 104 patients interviewed, 51 (49.04%) were clinical patients and 53 (50.96%) surgical. Based on risk stratification, 17 (16.35%) were classified as low risk, 37 (35.58%) as moderate risk, 46 (44.23%) as high risk and 4 (3.85%) as extremely high risk for DVT/PTE. A total of 68 patients (65.38%) received prophylaxis, but of these only 56 (53.85%) received the correct prophylaxis, and 36 (34.62%) did not receive any prophylaxis. CONCLUSION: The rates of prophylaxis use for DVT and PTE in this service are higher than rates published in the literature.

Comparison of initial loading doses of 5 mg and 10 mg for warfarin therapy

CONTEXT: The question of what is the best loading dosage of warfarin when starting anticoagulant treatment has been under discussion for ten years. We were unable to find any comparative studies of these characteristics conducted here in Brazil. OBJECTIVE: To compare the safety and efficacy of two initial warfarin dosage regimens for anticoagulant treatment. METHODS: One-hundred and ten consecutive patients of both sexes, with indications for anticoagulation because of venous or arterial thromboembolism, were analyzed prospectively. During the first 3 days of treatment, these patients were given adequate heparin to keep aPTT (activated partial thromboplastin time) between 1.5 and 2.5, plus 5 mg of warfarin. From the fourth day onwards, their warfarin doses were adjusted using International Normalized Ratios (INR; target range: 2 to 3). This prospective cohort was compared with a historical series of 110 patients had been given 10 mg of warfarin on the first 2 days and 5 mg on the third day with adjustments based on INR thereafter. Outcomes analyzed were as follows: recurrence of thromboembolism, bleeding events and time taken to enter the therapeutic range. RESULTS: Efficacy, safety and length of hospital stay were similar in both samples. The sample that were given 10 mg entered the therapeutic range earlier (means: 4.5 days vs. 5.8 days), were on lower doses at discharge and had better therapeutic indicators at the first return appointment. CONCLUSIONS: The 10 mg dosage regimen took less time to attain the therapeutic range and was associated with lower warfarin doses at discharge and better INR at first out-patients follow-up visit.

Warfarin and atrial fibrillation: from ideal to real the warfarin affaire

Vitamin K Antagonists (VKAs) are widely used in clinical practice and nearly 1% of the entire population receives oral anticoagulation at least once in life. However, the rate of prescription of anticoagulation is low, compared to what it should be. No more than 50-60% of patients affected by atrial fibrillation (AF) receive anticoagulation. In the setting of AF, VKAs are safe and effective when properly managed, reducing stroke and systemic embolism by more than 60%. VKAs safety and effectiveness are closely related to the quality of anticoagulation (e.g. time in therapeutic range), and anticoagulation clinics offer the best management of anticoagulant therapy. However, a sizeable proportion of patients are managed elsewhere. In clinical practice, in the setting of AF, a low prescription rate of VKAs is frequently observed and this is due also to difficulties in managing laboratory monitoring and drug dose adjustment. The suboptimal management of therapy with VKAs leads to a lesser efficacy than that reported in clinical trials, and to an increase in adverse reactions. VKAs still remain the first and only available therapy for a number of diseases (e.g. valvular atrial fibrillation and mechanical prosthetic heart valves). Now, since approval of the new oral anticoagulants (NOAs), the choice of anticoagulant therapy in definite settings, such as stroke prevention in non-valvular atrial fibrillation (SPAF) or treatment of venous thromboembolism, has surely become more intriguing but also more problematic. In light of these new therapeutic options, we reviewed VKAs therapy, in the setting of atrial fibrillation, focusing on VKAs impact in real life. We analyzed the data about efficacy and safety of warfarin at three levels: clinical trial and real life, outside and inside anticoagulation clinics.

New anticoagulant and antiplatelet agents: a primer for the gastroenterologist

A large number of patients worldwide receive anticoagulant and antiplatelet agents, collectively known as antithrombotic agents. Several new anticoagulants and antiplatelet agents recently were approved for use. Gastroenterologists may be unfamiliar with the mechanism of action, indications for use, and pharmacokinetics of these newer drugs. In patients undergoing elective and urgent endoscopic procedures, clinicians must be familiar with these medications to optimize outcomes. When the decision is made to continue the newer antithrombotic agents for elective procedures, the clinician must understand the risk that these agents may impart on procedural-induced bleeding. Finally, it is important to understand how to manage these agents in the presence of acute gastrointestinal bleeding. In this article the use of newer antithrombotic agents is reviewed.

Prothrombin complex concentrate

Each month, subscribers to The Formulary Monograph Service receive 5 to 6 well-documented monographs on drugs that are newly released or are in late phase 3 trials. The monographs are targeted to Pharmacy & Therapeutics Committees. Subscribers also receive monthly 1-page summary monographs on agents that are useful for agendas and pharmacy/nursing in-services. A comprehensive target drug utilization evaluation/medication use evaluation (DUE/MUE) is also provided each month. With a subscription, the monographs are sent in print and are also available on-line. Monographs can be customized to meet the needs of a facility. A drug class review is now published monthly with The Formulary Monograph Service. Through the cooperation of The Formulary, Hospital Pharmacy publishes selected reviews in this column. For more information about The Formulary Monograph Service, call The Formulary at 800-322-4349. The December 2013 monograph topics are vortioxetine, mechlorethamine gel, brimonidine tartrate topical gel, obinutuzumab, and miltefosine. The DUE/MUE is on vortioxetine.

Fondaparinux as alternative anticoagulant to warfarin or low-molecular-weight heparin for recurrent venous thrombosis

OBJECTIVE

Recurrent venous thromboembolism (VTE) occurs in some patients despite treatment with the standard drugs, warfarin and low-molecular-weight heparin (LMWH). Fondaparinux is currently licensed by the Food and Drug Administration for the prophylaxis of deep-vein thrombosis in patients undergoing orthopedic or abdominal surgery and also in the treatment of VTE. Well-documented use of this agent beyond these indications and for prolonged periods is currently limited.

CASE SUMMARY

Two cases of "refractory" VTE, managed effectively with long-term fondaparinux are described. In the first case, a 43-year-old man developed recurrent thrombosis while receiving warfarin at a higher target international normalized ratio (INR) of 3 to 4. In the second case, a 45-year-old man developed recurrent thrombosis on once-daily dalteparin. Both the patients were successfully managed with fondaparinux for 36 months and 14 months, respectively, with no sign of recurrent thrombosis or adverse effects.

DISCUSSION

In patients with recurrent VTE, fondaparinux is effective as daily injections as much as twice-daily LMWH or warfarin maintained on higher therapeutic-range INRs. Although the exact mechanism for this effectiveness is not yet understood, it provides a useful alternative to the standard therapies. In addition, the side effect profile is also favorable for fondaparinux, in that it causes less thrombocytopenia and skin reactions in comparison with heparins.

CONCLUSION

Daily fondaparinux injections may be an effective antithrombotic agent in patients who develop recurrent VTE on anticoagulation with warfarin or LMWH.

Evaluation of education on the appropriate use of vitamin k in warfarin reversal in adult inpatients

PURPOSE

Vitamin K (phytonadione) is a commonly used first-line reversal agent for vitamin K antagonist (VKA) therapy in patients presenting with a supratherapeutic international normalized ratio (INR) with or without significant bleeding or in patients with a therapeutic INR in need of surgery. The purpose of this study was to determine the impact of education on the appropriate use of vitamin K for VKA reversal.

METHODS

Data were collected on patients admitted to a community teaching hospital during February 2010 (pre-education group). These data were analyzed to determine the most common guideline deviations in vitamin K use. Following this analysis, pharmacist education took place in the form of in-service presentations; a protocol, including a guideline-based dosing table, was developed to assist pharmacists in evaluating vitamin K therapy. Data were then collected on patients admitted during February 2011 (post-education group).

RESULTS

Forty patients and 47 vitamin K administrations were included in the pre-education group, and 34 patients and 49 vitamin K administrations were included in the post-education group. The number of patients with appropriate vitamin K administrations improved after pharmacist education (25% pre-education vs 55.8% post-education; P = .01). Whereas 27.6% of individual vitamin K administrations were appropriate in the pre-education group, this increased to 63.2% in the post-education group (P = .04).

CONCLUSION

Education techniques on the appropriate use of vitamin K for VKA reversal significantly improved compliance with standards of care for proper use of vitamin K. Additional education sessions are necessary to further increase compliance with standards of care and subsequently optimize patient care.

The association of health literacy with time in therapeutic range for patients on warfarin therapy

Patients on warfarin therapy need to achieve and maintain anticoagulation control in order to experience the benefits of treatment while minimizing bleeding risk. Low health literacy skills may hinder patients' ability to use and adhere to warfarin in a safe and effective manner. The authors conducted this study to evaluate the relationship between health literacy and anticoagulation control among patients on chronic warfarin therapy. Participants were recruited from 2 diverse anticoagulation clinics in North Carolina. Time in therapeutic range (TTR) for warfarin therapy was used as a measure of anticoagulation control. Health literacy was assessed using the short form of the Test of Functional Health Literacy in Adults (S-TOFHLA). Of the 198 study participants, 51% had limited health literacy (S-TOFHLA score of 0-90) and 33% had poor anticoagulation control (TTR<50%). Participants with limited health literacy were less likely to correctly answer warfarin-related knowledge questions. Limited health literacy was significantly associated with TTR<50% (adjusted odds ratio=2.34, 95% CI [1.01, 5.46]). Findings indicate that limited health literacy is associated with poor anticoagulation control for patients on warfarin therapy. Lack of medication understanding may hinder the safe and effective use of this narrow therapeutic index drug.

Betrixaban (PRT054021): pharmacology, dose selection and clinical studies

ABSTRACT: The recently introduced oral anticoagulants, dabigatran, rivaroxaban and apixaban, were shown, in randomized controlled trials, to be at least as effective and safe as monitored warfarin therapy for the treatment of venous thromboembolism and stroke prevention in atrial fibrillation. These new oral anticoagulants have predictable pharmacology, less variability in anticoagulant effect and fewer drug and food interactions than warfarin, allowing unmonitored and fixed dosing, which renders their use appealing. The remaining limitations of currently available new oral anticoagulants include their dependence on renal and hepatic clearance, and the lack of an antidote, which is problematic in bleeding patients and those requiring urgent surgery. Betrixaban is a new direct factor Xa inhibitor with distinct pharmacological characteristics, including a long half-life, minimal renal clearance and minimal hepatic metabolism. Betrixaban was tested in Phase II studies in orthopedic thromboprophylaxis (EXPERT) and atrial fibrillation (EXPLORE-Xa), and is being evaluated in a Phase III trial of extended thromboprophylaxis in medical patients (APEX). This article details the pharmacology, preclinical and clinical development of betrixaban.

A randomized trial of genotype-guided dosing of warfarin

BACKGROUND

The level of anticoagulation in response to a fixed-dose regimen of warfarin is difficult to predict during the initiation of therapy. We prospectively compared the effect of genotype-guided dosing with that of standard dosing on anticoagulation control in patients starting warfarin therapy.

METHODS

We conducted a multicenter, randomized, controlled trial involving patients with atrial fibrillation or venous thromboembolism. Genotyping for CYP2C9*2, CYP2C9*3, and VKORC1 (-1639G→A) was performed with the use of a point-of-care test. For patients assigned to the genotype-guided group, warfarin doses were prescribed according to pharmacogenetic-based algorithms for the first 5 days. Patients in the control (standard dosing) group received a 3-day loading-dose regimen. After the initiation period, the treatment of all patients was managed according to routine clinical practice. The primary outcome measure was the percentage of time in the therapeutic range of 2.0 to 3.0 for the international normalized ratio (INR) during the first 12 weeks after warfarin initiation.

RESULTS

A total of 455 patients were recruited, with 227 randomly assigned to the genotype-guided group and 228 assigned to the control group. The mean percentage of time in the therapeutic range was 67.4% in the genotype-guided group as compared with 60.3% in the control group (adjusted difference, 7.0 percentage points; 95% confidence interval, 3.3 to 10.6; P<0.001). There were significantly fewer incidences of excessive anticoagulation (INR ≥4.0) in the genotype-guided group. The median time to reach a therapeutic INR was 21 days in the genotype-guided group as compared with 29 days in the control group (P<0.001).

CONCLUSIONS

Pharmacogenetic-based dosing was associated with a higher percentage of time in the therapeutic INR range than was standard dosing during the initiation of warfarin therapy. (Funded by the European Commission Seventh Framework Programme and others; ClinicalTrials.gov number, NCT01119300.).

Preventing thrombophilia-related complications of pregnancy: an update

Approximately half of all pregnancy-related venous thromboembolic events are associated with thrombophilia. Although the most compelling data for a link between thrombophilia and other adverse pregnancy outcomes derive from women with antiphospholipid antibodies, some studies also suggest an association between these pregnancy complications and hereditary thrombophilias. Management of thrombophilia often involves anticoagulant therapy; however, use of these agents during pregnancy is challenging. There is a paucity of high-quality studies and consequently, recommendations are based largely on extrapolation from data in nonpregnant women, in addition to observational studies and a few small randomized studies. This article will review the impact of the thrombophilias on pregnancy and its outcome, evidence for therapies aimed at the prevention of thrombophilia-related pregnancy complications, and the most recent recommendations contained in the 9th Edition of the American College of Chest Physicians Evidence-Based Clinical Practice Guidelines.

Development of an Anticoagulation Stewardship Program at a Large Tertiary Care Academic Institution

Pharmacist-directed anticoagulation management services (AMSs) have been shown to significantly lower anticoagulation-related mortality, length of hospital stay, bleeding complications, blood transfusion requirements, and cost of therapy. AMSs are only 1 component of an anticoagulation stewardship program. Frequently, stewardship programs are limited to inpatient populations. Incorporating components that facilitate transition to outpatient status will ideally encompass complete care. The purpose of this program was to expand anticoagulation services and standardize care by implementing a full-service stewardship program including a transition of care service. The first component of the study involved medication surveillance for inpatients on anticoagulation therapy. The second component involved transitioning patients on anticoagulation, primarily with venous thromboembolism (VTE) to outpatient management. Finally, the pharmacist identified areas for optimization. Optimization involved developing or updating protocols to reflect updates in the literature as well as updating institution-specific information resources. Interventions made through medication surveillance and utilization of the VTE transition of care services translated into a total cost savings of approximately US$270 320. A postgraduate, first-year pharmacy resident contributed to improving patient outcomes while reducing utilization of hospital services and obtaining substantial cost savings through participation in anticoagulation stewardship services.

The ASH Choosing Wisely® campaign: five hematologic tests and treatments to question

Choosing Wisely® is a medical stewardship and quality improvement initiative led by the American Board of Internal Medicine Foundation in collaboration with leading medical societies in the United States. The ASH is an active participant in the Choosing Wisely® project. Using an iterative process and an evidence-based method, ASH has identified 5 tests and treatments that in some circumstances are not well supported by evidence and which in certain cases involve a risk of adverse events and financial costs with low likelihood of benefit. The ASH Choosing Wisely® recommendations focus on avoiding liberal RBC transfusion, avoiding thrombophilia testing in adults in the setting of transient major thrombosis risk factors, avoiding inferior vena cava filter usage except in specified circumstances, avoiding the use of plasma or prothrombin complex concentrate in the nonemergent reversal of vitamin K antagonists, and limiting routine computed tomography surveillance after curative-intent treatment of non-Hodgkin lymphoma. We recommend that clinicians carefully consider anticipated benefits of the identified tests and treatments before performing them.

The ASH Choosing Wisely® campaign: five hematologic tests and treatments to question

Choosing Wisely® is a medical stewardship and quality improvement initiative led by the American Board of Internal Medicine Foundation in collaboration with leading medical societies in the United States. The ASH is an active participant in the Choosing Wisely® project. Using an iterative process and an evidence-based method, ASH has identified 5 tests and treatments that in some circumstances are not well supported by evidence and which in certain cases involve a risk of adverse events and financial costs with low likelihood of benefit. The ASH Choosing Wisely® recommendations focus on avoiding liberal RBC transfusion, avoiding thrombophilia testing in adults in the setting of transient major thrombosis risk factors, avoiding inferior vena cava filter usage except in specified circumstances, avoiding the use of plasma or prothrombin complex concentrate in the nonemergent reversal of vitamin K antagonists, and limiting routine computed tomography surveillance after curative-intent treatment of non-Hodgkin lymphoma. We recommend that clinicians carefully consider anticipated benefits of the identified tests and treatments before performing them.

Effect of extremes of body weight on the pharmacokinetics, pharmacodynamics, safety and tolerability of apixaban in healthy subjects

AIM

Apixaban is an oral, direct, factor-Xa inhibitor approved for thromboprophylaxis in patients who have undergone elective hip or knee replacement surgery and for prevention of stroke and systemic embolism in patients with non-valvular atrial fibrillation. This open label, parallel group study investigated effects of extremes of body weight on apixaban pharmacokinetics, pharmacodynamics, safety and tolerability.

METHOD

Fifty-four healthy subjects were enrolled [18 each into low (≤50 kg), reference (65-85 kg) and high (≥120 kg) body weight groups]. Following administration of a single oral dose of 10 mg apixaban, plasma and urine samples were collected for determination of apixaban pharmacokinetics and anti-factor Xa activity. Adverse events, vital signs and laboratory assessments were monitored.

RESULTS

Compared with the reference body weight group, low body weight had approximately 27% [90% confidence interval (CI): 8-51%] and 20% (90% CI: 11-42%) higher apixaban maximum observed plasma concentration (Cmax) and area under the concentration-time curve extrapolated to infinity (AUC(0,∞)), respectively, and high body weight had approximately 31% (90% CI: 18-41%) and 23% (90% CI: 9-35%) lower apixaban Cmax and AUC(0,∞) , respectively. Apixaban renal clearance was similar across the weight groups. Plasma anti-factor Xa activity showed a direct, linear relationship with apixaban plasma concentration, regardless of body weight group. Apixaban was well tolerated in this study.

CONCLUSION

The modest change in apixaban exposure is unlikely to require dose adjustment for apixaban based on body weight alone. However, caution is warranted in the presence of additional factors (such as severe renal impairment) that could increase apixaban exposure.

Rationale and methodology for a multicentre randomised trial of fibrinolysis for pulmonary embolism that includes quality of life outcomes

BACKGROUND

Submassive pulmonary embolism (PE) has a low mortality rate but can degrade functional capacity.

OBJECTIVE

The present study aims to provide rationale, methodology, and initial findings of a multicentre, randomised trial of fibrinolysis for PE that used a composite end-point, including quality of life measures.

METHODS

This investigator-initiated study was funded by a contract between a corporate partner and the investigator's hospital (the prime site). The investigator was the Food and Drug Administration (FDA) sponsor. The prime site subcontracted, indemnified, and trained consortia members. Consenting, normotensive patients with PE and right ventricular strain (by echocardiography or biomarkers) received low-molecular-weight heparin and random assignment to a single bolus of tenecteplase or placebo in double-blinded fashion. The outcomes were: (i) in-hospital rate of intubation, vasopressor support, and major haemorrhage, or (ii) at 90 days, death, recurrent PE, or composite that defined poor quality of life (echocardiography, 6 min walk test and surveys). The planned sample size was n = 200.

RESULTS

Eight sites enrolled 87 patients over 5 years. The ratio of patients screened for each enrolled was 7.4 to 1, equating to 11 h screening time per patient enrolled. Primary barrier to enrolment was the cost of screening. Two patients died (2.5%, 95%CI [0-8%]), one developed shock, but 18 (22%, 95%CI: [13-30%]) had a poor quality of life.

CONCLUSIONS

An investigator-initiated, FDA-regulated, multicentre trial of fibrinolysis for submassive PE was conducted, but was limited by screening costs and a low mortality rate. Quality of life measurements might represent a more important patient-centred end-point.