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

Comparison of prothrombin time (INR) results and main characteristics of patients on warfarin treatment in primary health care centers and anticoagulation clinics

Background

Oral anticoagulant therapy is used to prevent thrombosis in patients with atrial fibrillation (AF), venous thrombosis and prosthetic heart valves. The introduction of new therapies emphasizes the need to discern the best practice for the patients remaining on warfarin treatment. This study compares patient characteristics and therapeutic control in two settings managing warfarin treatment: Swedish primary health care centers (PHCC) and specialized anticoagulation clinics (ACC).

Methods

Prothrombin time (PT) test results reported as International Normalized Ratio (INR) were collected for five consecutive days from patients on warfarin treatment; 564 PHCC and 927 ACC patients. Therapeutic control was calculated as PT test results in relation to intended therapeutic range (TR). Mann–Whitney Rank Sum Test and Chi² test were used for statistical comparisons.

Results

The PHCC patients were older than the ACC patients, 76 v. 70 years (p<0.01) with a predominance of men in both groups. The reasons for treating differed between the groups. Seventy-two percent of PHCC patients and 66% of ACC patients had a PT-INR within the intended TR (p<0.05). Men generally had better results than women (72% v. 63%, p<0.001) and particularly in the PHCC group v. the ACC group (78% v. 69%, p<0.01).

PT-INR above intended TR was significantly more common in the ACC setting, (p<0.05), for women overall (p<0.01), for women in the PHCC setting, and for ACC men (p<0.05).

Conclusions

In this study both settings achieved good therapeutic control of warfarin treatment with a minor advantage for PHCC over ACC, and better results for men, especially in the PHCC setting. As patient characteristics differ between the PHCC and ACC, it is important to conduct further randomized studies to discern the best practice locally for warfarin management also after the introduction of new drugs.

Major bleeding of the upper aerodigestive tract due to oral anticoagulant/antibiotic interactions

INTRODUCTION

Although a well-known complication in certain medical specialties, major bleeding due to the interaction between oral anticoagulants and antibiotics has been rarely reported concerning the upper aerodigestive tract. We report three cases of life-threatening bleeding of the upper aerodigestive tract in a context of antibiotic therapy in patients treated with oral anticoagulants.

CASE SERIES

Three male patients under coumadin anticoagulation therapy presented major bleeding in three different contexts (epistaxis, peritonsillar abscess and postoperative course after total laryngectomy). Surgical intervention for hemostasis was required in all cases, with coagulation correction in two. Complications were severe anemia (2/3) and chronic heart failure (1/3).

DISCUSSION/CONCLUSIONS

Interactions between two drugs commonly used in otolaryngology can result in major bleeding. The goal of this article is to raise practitioners' awareness of a potentially fatal, although rare, complication. We also review the main preventive strategies.

Supplemental patient education for patients taking oral anticoagulants: systematic review and meta-analysis

OBJECTIVE

Lack of patient knowledge has been associated with poor anticoagulation control, but the effect of patient education on clinical outcomes is unclear. We systematically reviewed the effect of supplemental patient education vs. usual care on hemorrhage, thromboembolic events (TEEs), time in therapeutic range (TTR) and knowledge test scores for all oral anticoagulants.

DATA SOURCES

The data sources were electronic databases, including MEDLINE, EMBASE, CENTRAL, CINAHL and IPA, to February 2012 examining any oral anticoagulant. We reviewed references for additional potentially relevant studies.

METHODS

Only randomized controlled trials (RCTs) were considered. Data extraction and quality assessment were conducted with GRADE. Pooled relative risks (RRs) were calculated, and heterogeneity was determined by use of χ(2) and I(2) statistics.

RESULTS

Seven RCTs (n = 1209) were included in the systematic review, and five RCTs (n = 847) in the meta-analysis. All included studies examined vitamin K antagonists. No significant difference was found for hemorrhage (RR 0.92, 95% confidence interval [CI] 0.04-20.56), TEE (RR 0.66, 95% CI 0.10-4.39), a composite outcome of hemorrhage or TEE (RR 0.48, 95% CI 0.23-1.01), or TTR (mean absolute difference of 2.02%, 95% CI - 2.81 to 6.84). Evidence was conflicting on the impact of supplemental education on test scores. All trials had at least one substantial methodologic limitation.

CONCLUSION

Current evidence does not support supplemental patient education as a means to improve patient outcomes, but the quality of this evidence is poor. Larger randomized trials are needed with longer follow-up, recruitment of patients initiating anticoagulation in primary care settings, and clearly defined education interventions.

Anticoagulation education: do patients understand potential medication-related emergencies?

BACKGROUND

The Joint Commission Venous Thromboembolism (VTE) National Hospital Inpatient Quality Measure VTE-5 outlines four criteria for discharge patient education when starting anticoagulation (usually, warfarin) therapy. The criteria do not specify content regarding patient recognition of potentially dangerous warfarin-related scenarios. A study was conducted to investigate how well patients assess the risks and consequences of potential warfarin-related safety threats.

METHODS

From an adult population on long-term warfarin, 480 patients were randomly selected for a telephone-based survey. Warfarin-knowledge questions were drawn from a previous survey; warfarin-associated risk scenarios were developed via focus interviews. Expert anticoagulation pharmacists categorized each scenario as urgent, moderately urgent, or not urgent, as did survey participants.

RESULTS

For the 184 patients (38% completion rate), the mean knowledge score was 69% (standard deviation [SD], 0.20). Overall classification accuracy of situational urgency was 59% (95% confidence interval [CI], 57.3%-60.3%). Respondents overestimated non-urgent-severity situations 23% of the time (95% CI, 20.8%-24.7%), while underestimating urgent-severity situations 21% of the time (95% CI, 19.0%-23.9%). A significant percentage of patients failed to recognize the urgency of stroke symptoms (for example, loss of vision), the risk of bleeding after incidental head trauma, or medication mismanagement.

CONCLUSIONS

Despite fair factual warfarin knowledge, participants did not appear to recognize well the clinical severity of warfarin-associated scenarios. Warfarin education programs should incorporate patient-centered strategies to teach recognition of high-risk situations that compromise patient safety.

Management of intracranial hemorrhage in patients with left ventricular assist devices

OBJECT

The authors conducted a study to review outcomes and management in patients in whom intracranial hemorrhage (ICH) develops during left ventricular assist device (LVAD) therapy.

METHODS

This retrospective cohort study included all adult patients (18 years of age or older) at a single institution who underwent placement of an LVAD between January 1, 2003, and March 1, 2012. The authors conducted a detailed medical chart review, and data were abstracted to assess outcomes in patients in whom ICH developed compared to those in patients in whom ICH did not develop; to compare management of antiplatelet agents and anticoagulation with outcomes; to describe surgical management employed and outcomes achieved; to compare subtypes of ICH (intraparenchymal, subdural, and subarachnoid hemorrhage) and their outcomes; and to determine any predictors of outcome.

RESULTS

During the study period, 330 LVADs were placed and 36 patients developed an ICH (traumatic subarachnoid hemorrhage in 10, traumatic subdural hematoma in 8, spontaneous intraventricular hemorrhage in 1, and spontaneous intraparenchymal hemorrhage in 17). All patients were treated with aspirin and warfarin at the time of presentation. With suspension of these agents, no thromboembolic events or pump failures were seen and no delayed rehemorrhages occurred after resuming these medications. Intraparenchymal hemorrhages had the worst outcomes, with a 30-day mortality rate in 59% compared with a 30-day mortality rate of 0% in patients with traumatic subarachnoid hemorrhages and 13% in those with traumatic subdural hematomas. Five patients with intraparenchymal hemorrhages were managed with surgical intervention, 4 of whom died within 60 days. The only factor found to be predictive of outcome was initial Glasgow Coma Scale score. No patients with a Glasgow Coma Scale score less than 11 survived beyond 30 days. Overall, the development of an ICH significantly reduced survival compared with the natural history of patients on LVAD therapy.

CONCLUSIONS

The authors' data suggest that withholding aspirin for 1 week and warfarin for 10 days is sufficient to reduce the risk of hemorrhage expansion or rehemorrhage while minimizing the risk of thromboembolic events and pump failure. Patients with intraparenchymal hemorrhage have poor outcomes, whereas patients with traumatic subarachnoid hemorrhage or subdural hematoma have better outcomes.

Venous thromboembolism in cirrhosis: a review of the literature

Although hemorrhage has traditionally been regarded as the most significant hemostatic complication of liver disease, there is increasing recognition that hypercoagulability is a prominent aspect of cirrhosis. Identifying markers of coagulability and monitoring anticoagulation therapy in the setting of cirrhosis is problematic. The bleeding risk of venous thromboembolism (VTE) prophylaxis and treatment in patients with chronic liver disease is unclear and there are currently no recommendations to guide practice in this regard. In the present report, the mechanism of coagulation disturbance in chronic liver disease is reviewed with an examination of the evidence for an increased VTE risk in cirrhosis. Finally, the available evidence is assessed for prophylaxis and therapy of VTE in chronic liver disease, and the role it may play in decreasing clinical decompensation and improving survival.

[The 2013 Seville Consensus Document on alternatives to allogenic blood transfusion. An update on the Seville Document]

Since allogeneic blood transfusion (ABT) is not harmless, multiple alternatives to ABT (AABT) have emerged, though there is great variability in their indications and appropriate use. This variability results from the interaction of a number of factors, including the specialty of the physician, knowledge and preferences, the degree of anemia, transfusion policy, and AABT availability. Since AABTs are not harmless and may not meet cost-effectiveness criteria, such variability is unacceptable. The Spanish Societies of Anesthesiology (SEDAR), Hematology and Hemotherapy (SEHH), Hospital Pharmacy (SEFH), Critical Care Medicine (SEMICYUC), Thrombosis and Hemostasis (SETH) and Blood Transfusion (SETS) have developed a Consensus Document for the proper use of AABTs. A panel of experts convened by these 6 Societies have conducted a systematic review of the medical literature and have developed the 2013 Seville Consensus Document on Alternatives to Allogeneic Blood Transfusion, which only considers those AABT aimed at decreasing the transfusion of packed red cells. AABTs are defined as any pharmacological or non-pharmacological measure aimed at decreasing the transfusion of red blood cell concentrates, while preserving patient safety. For each AABT, the main question formulated, positively or negatively, is: "Does this particular AABT reduce the transfusion rate or not?" All the recommendations on the use of AABTs were formulated according to the Grades of Recommendation Assessment, Development and Evaluation (GRADE) methodology.

Common complications in the critically ill patient

Critically ill patients in intensive care units are subject to many complications associated with therapy. Many of these complications are health care-associated infections and are related to indwelling devices, including ventilator-associated pneumonia, central line-associated bloodstream infection, catheter-associated urinary tract infection; surgical site infection, venous thromboembolism, deep venous thrombosis, and pulmonary embolus are other common complications. All efforts should be undertaken to prevent these complications in surgical critical care, and national efforts are under way for each of these complications. In this article, epidemiology, risk factors, diagnosis, treatment, and prevention of these complications in critically ill patients are discussed.

A French multicenter randomised trial comparing two dose-regimens of prothrombin complex concentrates in urgent anticoagulation reversal

INTRODUCTION

Prothrombin complex concentrates (PCC) are haemostatic blood preparations indicated for urgent anticoagulation reversal, though the optimal dose for effective reversal is still under debate. The latest generation of PCCs include four coagulation factors, the so-called 4-factor PCC. The aim of this study was to compare the efficacy and safety of two doses, 25 and 40 IU/kg, of 4-factor PCC in vitamin K antagonist (VKA) associated intracranial haemorrhage.

METHODS

We performed a phase III, prospective, randomised, open-label study including patients with objectively diagnosed VKA-associated intracranial haemorrhage between November 2008 and April 2011 in 22 centres in France. Patients were randomised to receive 25 or 40 IU/kg of 4-factor PCC. The primary endpoint was the international normalised ratio (INR) 10 minutes after the end of 4-factor PCC infusion. Secondary endpoints were changes in coagulation factors, global clinical outcomes and incidence of adverse events (AEs).

RESULTS

A total of 59 patients were randomised: 29 in the 25 IU/kg and 30 in the 40 IU/kg group. Baseline demographics and clinical characteristics were comparable between the groups. The mean INR was significantly reduced to 1.2 - and ≤1.5 in all patients of both groups - 10 minutes after 4-factor PCC infusion. The INR in the 40 IU/kg group was significantly lower than in the 25 IU/kg group 10 minutes (P = 0.001), 1 hour (P = 0.001) and 3 hours (P = 0.02) after infusion. The 40 IU/kg dose was also effective in replacing coagulation factors such as PT (P = 0.038), FII (P = 0.001), FX (P <0.001), protein C (P = 0.002) and protein S (0.043), 10 minutes after infusion. However, no differences were found in haematoma volume or global clinical outcomes between the groups. Incidence of death and thrombotic events was similar between the groups.

CONCLUSIONS

Rapid infusion of both doses of 4-factor PCC achieved an INR of 1.5 or less in all patients with a lower INR observed in the 40 IU/kg group. No safety concerns were raised by the 40 IU/kg dose. Further trials are needed to evaluate the impact of the high dose of 4-factor PCC on functional outcomes and mortality.

TRIAL REGISTRATION

Eudra CT number 2007-000602-73.

Transitions of care in anticoagulation management for patients with atrial fibrillation

Thromboprophylaxis with oral anticoagulants (OACs) is an important but underused element of atrial fibrillation (AF) treatment. Reduction of stroke risk with anticoagulants comes at the price of increased bleeding risk. Patients with AF receiving anticoagulants require heightened attention with transition from one care setting to another. Patients presenting for emergency care of anticoagulant-related bleeding should be triaged for the severity and source of the bleeding using appropriate measures, such as discontinuing the OAC, administering vitamin K, when appropriate, to reverse warfarin-induced bleeding, or administering clotting factors for emergent bleeding. Reversal of OACs in patients admitted to the hospital for surgery can be managed similarly to patients with bleeding, depending on the urgency of the surgical procedure. Patients with AF who are admitted for conditions unrelated to AF should be assessed for adequacy of stroke risk prophylaxis and bleeding risk. Newly diagnosed AF should be treated in nearly all patients with either warfarin or a newer anticoagulant. Patient education is critically important with all anticoagulants. Close adherence to the prescribed regimen, regular international normalized ratio testing for warfarin, and understanding the stroke risk conferred by both AF and aging are goals for all patients receiving OACs. Detailed handoff from the hospitalist to the patient's primary care physician is required for good continuity of care. Monitoring by an anticoagulation clinic is the best arrangement for most patients. The elderly, or particularly frail or debilitated patients who are transferring to long-term care, need a detailed transfer of information between settings, education for the patient and family, and medication reconciliation. Communication and coordination of care among outpatient, emergency, inpatient, and long-term care settings are vital for patients with AF who are receiving anticoagulants to balance stroke prevention and bleeding risk.

Phase 4 research: what happens when the rubber meets the road?

Approval of a novel drug is oftentimes seen as the end of the development pathway. However, the appearance of rare but serious side effects in patients taking approved drugs has led to increased attention to phase 4, or postmarketing, research. Traditionally, postmarketing research relied on reports from clinicians to monitor for unexpected toxicity. However, such reporting will produce a biased assessment of risk due to underreporting of toxic effects in older medications. The availability of large, representative databases and more flexible analysis tools has led to comprehensive and near "real-time" surveillance programs. These programs have been used by the US Food and Drug Administration to explore toxicities of approved medications. The need for effective tools with which to monitor clinically relevant outcome events has been further increased by the development of accelerated pathways to drug approval. In areas without effective treatments, such pathways lead to licensure without rigorous clinical efficacy data. Continued approval is frequently made contingent on the availability of postmarketing surveillance data demonstrating improvements in clinical end points and these data can also be used to monitor for unexpected toxicity.

The old and new: PCCs, VIIa, and long-lasting clotting factors for hemophilia and other bleeding disorders

What is the correct use of established clotting factors, prothrombin complex concentrates (PCCs), and activated factor VII in bleeding complications of trauma, surgery, and old and new oral anticoagulants? How will new clotting factors, specifically the long-acting factors, change the hemostatic management of coagulation deficiency disorders? From bench to bedside, comparative coagulation studies and clinical trials of modified clotting factors are providing insights to help guide hemostatic management of congenital and acquired bleeding disorders. Comparative thrombin-generation studies and preclinical and clinical trials suggest that PCCs and fresh-frozen plasma are effective in reversing the anticoagulant effects of warfarin, yet there are few data to guide reversal of the new oral anticoagulants dabigatran and rivaroxaban. Although coagulation studies support the use of PCCs to reverse new oral anticoagulants, correlation with clinical response is variable and clinical trials in bleeding patients are needed. For congenital bleeding disorders, exciting new technologies are emerging from the bench. Data from clinical trials of molecularly modified coagulation factors with extended half-lives suggest the possibility of fewer infusions, reduced bleeds, and better quality of life in persons with hemophilia. Preclinical studies of other novel prohemostatic approaches for hemophilia and other congenital coagulation disorders include RNA interference silencing of antithrombin, monoclonal anti-tissue factor pathway inhibitor (anti-antibody, anti-tissue factor pathway inhibitor) aptamer, bispecific anti-IXa/X antibody, and fucoidans. Understanding the comparative coagulation studies of established prohemostatic agents, the pharmacokinetics of new long-acting clotting factors, and their correlation with bleeding outcomes will provide opportunities to optimize the hemostatic management of both congenital and acquired hemostatic disorders.

Care transitions in anticoagulation management for patients with atrial fibrillation: an emphasis on safety

BACKGROUND

Thromboprophylaxis with oral anticoagulants is an important but underused element of atrial fibrillation (AF) treatment. Reduction of stroke risk by anticoagulants comes at the price of bleeding risk. Patients with AF receiving anticoagulants require heightened attention with transition from one care setting to another.

METHODS

This review of the literature focuses on issues specific to the anticoagulation treatment of patients with AF.

RESULTS

Patients presenting for emergency care of anticoagulant-related bleeding should be triaged for the severity and source of the bleeding using appropriate measures, such as discontinuing the oral anticoagulant, administering vitamin K when appropriate to reverse warfarin-induced bleeding, or administering clotting factors for emergent bleeding. Reversal of oral anticoagulants in patients admitted to the hospital for surgery can be managed similarly to patients with bleeding, depending on the urgency of the surgical procedure. Patients with AF who are admitted for conditions unrelated to AF should be assessed for adequacy of stroke risk prophylaxis and bleeding risk. Newly diagnosed AF should be treated in nearly all patients with either warfarin or a newer anticoagulant.

CONCLUSIONS

Patient education is critically important with all anticoagulants. Close adherence to the prescribed regimen, regular international normalized ratio testing for warfarin, and understanding the stroke risk conferred by AF and aging are goals for all patients receiving oral anticoagulants. Detailed handoff from the hospitalist to the patient's primary care physician is required for good continuity of care. Monitoring by an anticoagulation clinic is the best arrangement for most patients. The elderly, particularly frail or debilitated patients who are transferring to long-term care, need a detailed transfer of information between settings, education for the patient and family, and medication reconciliation. Communication and coordination of care among outpatient, emergency, inpatient, subacute, and long-term care settings are vital in patients with AF who are receiving anticoagulants to balance stroke prevention and bleeding risk.

Comparison of international normalized ratio measurement between CoaguChek XS Plus and STA-R coagulation analyzers

Background. Point-of-care testing (POCT) coagulometers are increasingly being used in the hospital setting. We investigated whether the prothrombin time international normalized ratio (INR) results by CoaguChek XS Plus (Roche Diagnostics GmbH, Mannheim, Germany) can be used reliably without being confirmed with the INR results by STA-R system (Diagnostica Stago S.A.S, Asnières sur Seine, France). Methods. A total of 118 INR measurements by CoaguChek XS Plus and STA-R were compared using Passing/Bablok regression analysis and Bland-Altman plot. Agreement of the INR measurements was further assessed in relation to dosing decision. Results. The correlation of INR measurements between CoaguChek XS Plus and STA-R was excellent (correlation coefficient = 0.964). The mean difference tended to increase as INR results increased and was 0.25 INR in the therapeutic range (2.0-3.0 INR). The overall agreement was fair to good (kappa = 0.679), and 21/118 (17.8%) INR measurements showed a difference in dosing decision. Conclusion. The positive bias of CoaguChek XS Plus may be obvious even in the therapeutic INR range, and dosing decision based on the CoaguChek XS Plus INR results would be different from that based on the STA-R results. The INR measurements by POCT coagulometers still need to be confirmed with the laboratory INR measurements.

Evaluation of the Q analyzer, a new cap-piercing fully automated coagulometer with clotting, chromogenic, and immunoturbidometric capability

The Q analyzer is a recently launched fully automated photo-optical analyzer equipped with primary tube cap-piercing and capable of clotting, chromogenic, and immunoturbidometric tests. The purpose of the present study was to evaluate the performance characteristics of the Q analyzer with reagents from the instrument manufacturer. We assessed precision and throughput when performing coagulation screening tests, prothrombin time (PT)/international normalized ratio (INR), activated partial thromboplastin time (APTT), and fibrinogen assay by Clauss assay. We compared results with established reagent instrument combinations in widespread use. Precision of PT/INR and APTT was acceptable as indicated by total precision of around 3%. The time to first result was 3  min for an INR and 5  min for PT/APTT. The system produced 115 completed samples per hour when processing only INRs and 60 samples (120 results) per hour for PT/APTT combined. The sensitivity of the DG-APTT Synth/Q method to mild deficiency of factor VIII (FVIII), IX, and XI was excellent (as indicated by APTTs being prolonged above the upper limit of the reference range). The Q analyzer was associated with high precision, acceptable throughput, and good reliability. When used in combination with DG-PT reagent and manufacturer's instrument-specific international sensitivity index, the INRs obtained were accurate. The Q analyzer with DG-APTT Synth reagent demonstrated good sensitivity to isolated mild deficiency of FVIII, IX, and XI and had the advantage of relative insensitivity to mild FXII deficiency. Taken together, our data indicate that the Q hemostasis analyzer was suitable for routine use in combination with the reagents evaluated.

Vitamin K dosing to reverse warfarin based on INR, route of administration, and home warfarin dose in the acute/critical care setting

BACKGROUND

Vitamin K is commonly used for reversal of anticoagulation of warfarin. However, the optimal dose and route of vitamin K that does not increase the duration of bridging therapy is unknown.

OBJECTIVE

To determine factors influencing the extent and rate of INR reversal with vitamin K in the acute/critical care setting.

METHODS

This was a chart review of 400 patients who received vitamin K for reversal of warfarin effects between February 2008 and November 2010. Data collected included international normalized ratios (INRs) 12 hours, 24 hours, and 48 hours prior to vitamin K administration; intravenous or oral vitamin K dose; and whether or not fresh frozen plasma (FFP) was administered.

RESULTS

Intravenous vitamin K reduced INR more rapidly than oral vitamin K (5.09, 1.91, 1.54, and 1.41 vs 5.67, 2.90, 2.14, and 1.58) at baseline, 12, 24, and 48 hours, respectively. The dose of vitamin K (p < 0.001), route of administration (p < 0.001), and baseline INR (p < 0.001) influenced subsequent INR values. The INR reduction was similar for intravenous vitamin K doses 2 mg or greater. Home warfarin dose did not affect INR responses to intravenous (p = 0.27) or oral vitamin K (p = 0.98). FFP did not influence INR values at 48 hours. Although longer anticoagulation bridge therapy seemed to be associated with higher vitamin K doses, the incidence (p = 0.63) and duration (p = 0.61) were not significant.

CONCLUSIONS

Vitamin K dose, route, and initial INR influence subsequent INR values. INR reduction is similar for intravenous vitamin K doses of 2 mg or greater. Preadministration of FFP does not alter INR values at 48 hours or more after vitamin K administration.

Anticoagulant use in real time

Venous thromboembolism (VTE) encompasses deep vein thrombosis (DVT) and pulmonary embolism (PE). Each year, VTE affects about 300,000 to 600,000 people in the United States, and death is the first manifestation in one-fourth of this population.(1){Beckman, 2010 #79} Moreover, approximately 10% of the US population has genetic factors that increase their risk for developing thrombosis.(1) In addition to inherited disorders, factors that contribute to VTE include prolonged immobilization, trauma, surgery, cancer, and critically ill patients.(2) Routine assessment and prophylaxis are recommended in these groups to avoid DVT-related complications.(2) Anticoagulants are the mainstay of drugs used in DVT/PE prevention and treatment. Despite the availability of evidence-based guidelines for anticoagulant therapy, there is suboptimal implementation of DVT prophylaxis in hospitalized patients.(3) All anticoagulants are "high-alert" drugs, and judicious use is mandatory to prevent bleeding complications.(4) This review discusses treatment guidelines, monitoring, side effects, and reversal agents available for some anticoagulant drugs approved for VTE. Dissemination of the knowledge via pharmacy education programs significantly improves the adherence to VTE prophylaxis.(5) Understanding the clinical aspects of anticoagulant dispensing as presented in this review is hoped to facilitate implementation of the theoretical knowledge as well as evidence-based guidelines in order to maximize patient benefit.

Is home monitoring of international normalised ratio safer than clinic-based monitoring?

A best evidence topic was written according to a structured protocol, to answer the question: 'In patients taking warfarin, is home self-monitoring of international normalized ratio (INR) safer than clinic-based testing in reducing bleeding, thrombotic events and death?' Altogether, 268 papers were found using the reported search. Five papers represented the highest level of evidence to answer the clinical question (four systematic reviews with meta-analysis and one meta-analysis). The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. The principal outcomes of interest were death, major haemorrhage, major thromboembolism, and time (or percentage time) spent within the therapeutic range, compared between self-monitoring/self-management and conventional management. Self-monitoring/self-management was associated with a significantly reduced risk of all-cause mortality of 26-42%. All meta-analyses reported on major thromboembolism, finding significant reductions in risk of ~50%. One meta-analysis found a 35% reduction in the risk of major haemorrhage, with the other four studies finding no significant difference. Only one study found self-monitoring/self-management to be associated with a significantly greater proportion of time within range, with another finding no significant difference in either the percentage of therapeutic results or in the time within range. The remaining two could not combine data for meta-analysis owing to methodological heterogeneity. We conclude that self-monitoring/self-management appears to be safer than conventional management. It is associated with consistently lower rates of thromboembolism and may also be associated with reduced risk of bleeding and death. This supports the updated guidance from the American College of Chest Physicians, recommending self-management of INR for patients who are both competent and motivated.

Warfarin pharmacogenetics: does more accurate dosing benefit patients?

After a decade of clinical investigation, pharmacogenetic-guided initial dosing of warfarin is at a crossroads. Genotypes for two single nucleotide polymorphisms (SNPs) in the cytochrome P 450 2C9 gene, affecting warfarin metabolism, and one SNP in vitamin K reductase complex 1 gene, affecting warfarin sensitivity, account for approximately 30% of therapeutic warfarin dosing variability in whites and Asians. Incorporating this genetic information, along with patient's age, body size, and other clinical information improves the accuracy of initial warfarin dosing. Currently, there is insufficient evidence to support the clinical benefits and cost effectiveness of routine warfarin pharmacogenetics. Results from ongoing international randomized clinical trials should provide clarity about the place of warfarin pharmacogenetics in personalized medicine.

Bleeding risks and response to therapy in patients with INR higher than 9

An international normalized ratio (INR) higher than 9 is associated with a high risk of bleeding, yet most studies have focused on outpatients with lower INR. We retrospectively analyzed diagnosis, bleeding, treatment, and mortality in 162 patients with INR higher than 9, including inpatients and outpatients with and without warfarin treatment. Patients without anticoagulant treatment with INR higher than 9 had a poor prognosis, 67% experienced bleeding and 74% died. Among outpatients receiving warfarin with INR higher than 9, 11% had bleeding, but none died. Among inpatients receiving warfarin, 35% had bleeding and 17% died. Factors associated with bleeding were older age, renal failure, and alcohol use. Withholding warfarin or giving vitamin K treatment was ineffective at reducing the INR within 24 hours, whereas plasma infusion immediately dropped the INR to 2.4 ± 0.9. Because of underlying disease, comorbidities, and medications, hospitalized patients with INR higher than 9 may not respond quickly to withholding warfarin or vitamin K treatment, and plasma infusion may be needed to reduce INR and the risk of bleeding within 24 hours.

Reversal of drug-induced anticoagulation: old solutions and new problems

Anticoagulant drugs are taken by millions of patients throughout the world. Warfarin has been the most widely prescribed anticoagulant for decades. In recent years, new oral anticoagulants have been approved for use, are being positioned as alternatives to warfarin, and represent an enormous market opportunity for pharmaceutical companies. Requests for urgent reversal of anticoagulants are not uncommon especially in the setting of critical bleeding. This review summarizes information on reversal of warfarin by vitamin K, plasma, prothrombin complex concentrates, and recombinant VIIa. In addition, we emphasize the lack of current evidence supporting reversibility of the new oral direct thrombin inhibitors and Factor Xa inhibitors. This review is presented to assist transfusion medicine specialists, hematologists, and other clinicians who prescribe blood components for reversal of drug-induced anticoagulation.

Guidance on the emergent reversal of oral thrombin and factor Xa inhibitors

The new oral anticoagulants dabigatran, rivaroxaban and apixaban have advantages over warfarin which include no need for laboratory monitoring, less drug-drug interactions and less food-drug interactions. However, there is no established antidote for patients who are bleeding or require emergent surgery and there is a paucity of evidence to guide the clinical care during these situations. Members of thrombosis and anticoagulation groups participating in the Thrombosis and Hemostasis Summit of North America formulated expert opinion guidance for reversing the anticoagulant effect of the new oral anticoagulants and suggest: routine supportive care, activated charcoal if drug ingestion was within a couple of hours, and hemodialysis if feasible for dabigatran. Also, the pros and cons of the possible use of four factor prothrombin complex concentrate are discussed.

Antithrombotic therapy for atrial fibrillation: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines

BACKGROUND

The risk of stroke varies considerably across different groups of patients with atrial fibrillation (AF). Antithrombotic prophylaxis for stroke is associated with an increased risk of bleeding. We provide recommendations for antithrombotic treatment based on net clinical benefit for patients with AF at varying levels of stroke risk and in a number of common clinical scenarios.

METHODS

We used the methods described in the Methodology for the Development of Antithrombotic Therapy and Prevention of Thrombosis Guidelines: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines article of this supplement.

RESULTS

For patients with nonrheumatic AF, including those with paroxysmal AF, who are (1) at low risk of stroke (eg, CHADS(2) [congestive heart failure, hypertension, age ≥ 75 years, diabetes mellitus, prior stroke or transient ischemic attack] score of 0), we suggest no therapy rather than antithrombotic therapy, and for patients choosing antithrombotic therapy, we suggest aspirin rather than oral anticoagulation or combination therapy with aspirin and clopidogrel; (2) at intermediate risk of stroke (eg, CHADS(2) score of 1), we recommend oral anticoagulation rather than no therapy, and we suggest oral anticoagulation rather than aspirin or combination therapy with aspirin and clopidogrel; and (3) at high risk of stroke (eg, CHADS(2) score of ≥ 2), we recommend oral anticoagulation rather than no therapy, aspirin, or combination therapy with aspirin and clopidogrel. Where we recommend or suggest in favor of oral anticoagulation, we suggest dabigatran 150 mg bid rather than adjusted-dose vitamin K antagonist therapy.

CONCLUSIONS

Oral anticoagulation is the optimal choice of antithrombotic therapy for patients with AF at high risk of stroke (CHADS(2) score of ≥ 2). At lower levels of stroke risk, antithrombotic treatment decisions will require a more individualized approach.

Antithrombotic therapy for VTE disease: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines

BACKGROUND

This article addresses the treatment of VTE disease.

METHODS

We generated strong (Grade 1) and weak (Grade 2) recommendations based on high-quality (Grade A), moderate-quality (Grade B), and low-quality (Grade C) evidence.

RESULTS

For acute DVT or pulmonary embolism (PE), we recommend initial parenteral anticoagulant therapy (Grade 1B) or anticoagulation with rivaroxaban. We suggest low-molecular-weight heparin (LMWH) or fondaparinux over IV unfractionated heparin (Grade 2C) or subcutaneous unfractionated heparin (Grade 2B). We suggest thrombolytic therapy for PE with hypotension (Grade 2C). For proximal DVT or PE, we recommend treatment of 3 months over shorter periods (Grade 1B). For a first proximal DVT or PE that is provoked by surgery or by a nonsurgical transient risk factor, we recommend 3 months of therapy (Grade 1B; Grade 2B if provoked by a nonsurgical risk factor and low or moderate bleeding risk); that is unprovoked, we suggest extended therapy if bleeding risk is low or moderate (Grade 2B) and recommend 3 months of therapy if bleeding risk is high (Grade 1B); and that is associated with active cancer, we recommend extended therapy (Grade 1B; Grade 2B if high bleeding risk) and suggest LMWH over vitamin K antagonists (Grade 2B). We suggest vitamin K antagonists or LMWH over dabigatran or rivaroxaban (Grade 2B). We suggest compression stockings to prevent the postthrombotic syndrome (Grade 2B). For extensive superficial vein thrombosis, we suggest prophylactic-dose fondaparinux or LMWH over no anticoagulation (Grade 2B), and suggest fondaparinux over LMWH (Grade 2C).

CONCLUSION

Strong recommendations apply to most patients, whereas weak recommendations are sensitive to differences among patients, including their preferences.

Antithrombotic and thrombolytic therapy for valvular disease: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines

BACKGROUND

Antithrombotic therapy in valvular disease is important to mitigate thromboembolism, but the hemorrhagic risk imposed must be considered.

METHODS

The methods of this guideline follow those described in Methodology for the Development of Antithrombotic Therapy and Prevention of Thrombosis Guidelines. Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines in this supplement.

RESULTS

In rheumatic mitral disease, we recommend vitamin K antagonist (VKA) therapy when the left atrial diameter is > 55 mm (Grade 2C) or when complicated by left atrial thrombus (Grade 1A). In candidates for percutaneous mitral valvotomy with left atrial thrombus, we recommend VKA therapy until thrombus resolution, and we recommend abandoning valvotomy if the thrombus fails to resolve (Grade 1A). In patients with patent foramen ovale (PFO) and stroke or transient ischemic attack, we recommend initial aspirin therapy (Grade 1B) and suggest substitution of VKA if recurrence (Grade 2C). In patients with cryptogenic stroke and DVT and a PFO, we recommend VKA therapy for 3 months (Grade 1B) and consideration of PFO closure (Grade 2C). We recommend against the use of anticoagulant (Grade 1C) and antiplatelet therapy (Grade 1B) for native valve endocarditis. We suggest holding VKA therapy until the patient is stabilized without neurologic complications for infective endocarditis of a prosthetic valve (Grade 2C). In the first 3 months after bioprosthetic valve implantation, we recommend aspirin for aortic valves (Grade 2C), the addition of clopidogrel to aspirin if the aortic valve is transcatheter (Grade 2C), and VKA therapy with a target international normalized ratio (INR) of 2.5 for mitral valves (Grade 2C). After 3 months, we suggest aspirin therapy (Grade 2C). We recommend early bridging of mechanical valve patients to VKA therapy with unfractionated heparin (DVT dosing) or low-molecular-weight heparin (Grade 2C). We recommend long-term VKA therapy for all mechanical valves (Grade 1B): target INR 2.5 for aortic (Grade 1B) and 3.0 for mitral or double valve (Grade 2C). In patients with mechanical valves at low bleeding risk, we suggest the addition of low-dose aspirin (50-100 mg/d) (Grade 1B). In valve repair patients, we suggest aspirin therapy (Grade 2C). In patients with thrombosed prosthetic valve, we recommend fibrinolysis for right-sided valves and left-sided valves with thrombus area < 0.8 cm(2) (Grade 2C). For patients with left-sided prosthetic valve thrombosis and thrombus area ≥ 0.8 cm(2), we recommend early surgery (Grade 2C).

CONCLUSIONS

These antithrombotic guidelines provide recommendations based on the optimal balance of thrombotic and hemorrhagic risk.

Patient values and preferences in decision making for antithrombotic therapy: a systematic review: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines

BACKGROUND

Development of clinical practice guidelines involves making trade-offs between desirable and undesirable consequences of alternative management strategies. Although the relative value of health states to patients should provide the basis for these trade-offs, few guidelines have systematically summarized the relevant evidence. We conducted a systematic review relating to values and preferences of patients considering antithrombotic therapy.

METHODS

We included studies examining patient preferences for alternative approaches to antithrombotic prophylaxis and studies that examined, in the context of antithrombotic prophylaxis or treatment, how patients value alternative health states and experiences with treatment. We conducted a systematic search and compiled structured summaries of the results. Steps in the process that involved judgment were conducted in duplicate.

RESULTS

We identified 48 eligible studies. Sixteen dealt with atrial fibrillation, five with VTE, four with stroke or myocardial infarction prophylaxis, six with thrombolysis in acute stroke or myocardial infarction, and 17 with burden of antithrombotic treatment.

CONCLUSION

Patient values and preferences regarding thromboprophylaxis treatment appear to be highly variable. Participant responses may depend on their prior experience with the treatments or health outcomes considered as well as on the methods used for preference elicitation. It should be standard for clinical practice guidelines to conduct systematic reviews of patient values and preferences in the specific content area.

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

BACKGROUND

The objective of this article is to summarize the published literature concerning the pharmacokinetics and pharmacodynamics of oral anticoagulant drugs that are currently available for clinical use and other aspects related to their management.

METHODS

We carried out a standard review of published articles focusing on the laboratory and clinical characteristics of the vitamin K antagonists; the direct thrombin inhibitor, dabigatran etexilate; and the direct factor Xa inhibitor, rivaroxaban

RESULTS

The antithrombotic effect of each oral anticoagulant drug, the interactions, and the monitoring of anticoagulation intensity are described in detail and discussed without providing specific recommendations. Moreover, we describe and discuss the clinical applications and optimal dosages of oral anticoagulant therapies, practical issues related to their initiation and monitoring, adverse events such as bleeding and other potential side effects, and available strategies for reversal.

CONCLUSIONS

There is a large amount of evidence on laboratory and clinical characteristics of vitamin K antagonists. A growing body of evidence is becoming available on the first new oral anticoagulant drugs available for clinical use, dabigatran and rivaroxaban.

[Stereophotography of the ocular fundus. 2. Observation method]

Traditional anticoagulant agents such as vitamin K antagonists (VKAs), unfractionated heparin (UFH), low molecular weight heparins (LMWHs) and fondaparinux have been widely used in the prevention and treatment of thromboembolic diseases. However, these agents are associated with limitations, such as the need for regular coagulation monitoring (VKAs and UFH) or a parenteral route of administration (UFH, LMWHs and fondaparinux).

Several non-VKA oral anticoagulants (NOACs) are now widely used in the prevention and treatment of thromboembolic diseases and in stroke prevention in non-valvular atrial fibrillation. Unlike VKAs, NOACs exhibit predictable pharmacokinetics and pharmacodynamics. They are therefore usually given at fixed doses without routine coagulation monitoring. However, in certain patient populations or special clinical circumstances, measurement of drug exposure may be useful, such as in suspected overdose, in patients experiencing a hemorrhagic or thromboembolic event during the treatment’s period, in those with acute renal failure, in patients who require urgent surgery or in case of an invasive procedure. This article aims at providing guidance on laboratory testing of classic anticoagulants and NOACs.