Ovulation provides excessive coagulation and hepatocyte growth factor signals to cause postoperative intraabdominal adhesions

Postoperative adhesions show a higher occurrence in females aged 16-60, especially after pelvic surgeries. This study explores the role of ovulation in adhesion formation in mice. Ovarian surgery in mice with normal- or super-ovulation led to pronounced adhesions, whereas ovulation-defective Pgr-KO mice showed minimal adhesions. Specifically, exposure to ovulatory follicular fluid (FF) markedly increased the adhesion. The hazardous exposure time window was one day before to 2.5 days after the surgery. Mechanistically, early FF exposure triggered adhesions via the blood coagulation cascade, while later exposure relied on the HGF/cMET signaling pathway. Prophylactic administration of a thrombin inhibitor pre-operatively or a cMET inhibitor postoperatively effectively mitigated FF-induced adhesions, while COX inhibitor treatment exhibited no discernible effect. These findings underscore ovulation as a pivotal factor in the development of pelvic wound adhesions and advocate for targeted preventive strategies such as c-MET inhibition, scheduling surgeries outside the ovulatory period, or employing oral contraceptive measures.

Anticoagulation in the Management of Acute Pulmonary Embolism-A Review

Venous thromboembolism (VTE) is a very frequent cardiovascular entity that encompasses deep vein thrombosis and pulmonary embolism (PE). This last entity represents a major cause of cardiovascular morbidity and mortality. The incidence of PE and the rate of PE-related morbidity significantly increase with age, race, and underlying medical conditions, such as malignancy. Given the recent advances in diagnostic strategies and algorithms, patients can be risk assessed and treated promptly to avoid disease progression. Anticoagulation is the mainstay of treatment for acute PE that is not hemodynamically unstable. Direct oral anticoagulants, such as apixaban, rivaroxaban, or edoxaban, are currently the preferred agents for the treatment of patients who present with acute PE or for long-term treatment. Treatment duration should be continued for at least 3 months, and all patients should be assessed for extended duration of therapy based on the precipitating factors that led to the development of the VTE. Novel anticoagulant agents targeting factor XI/XIa are currently being investigated in phases 2 and 3 clinical trials, representing an attractive option in anticoagulation therapies in patients with VTE. For hemodynamically unstable patients, systemic thrombolysis is the treatment of choice, and it may also be of benefit-in reduced dose-for patients with intermediate to high risk who are at risk of hemodynamic collapse.

Pathophysiological Role of Microglial Activation Induced by Blood-Borne Proteins in Alzheimer's Disease

The blood-brain barrier (BBB) restricts entry of neurotoxic plasma components, blood cells, and pathogens into the brain, leading to proper neuronal functioning. BBB impairment leads to blood-borne protein infiltration such as prothrombin, thrombin, prothrombin kringle-2, fibrinogen, fibrin, and other harmful substances. Thus, microglial activation and release of pro-inflammatory mediators commence, resulting in neuronal damage and leading to impaired cognition via neuroinflammatory responses, which are important features observed in the brain of Alzheimer's disease (AD) patients. Moreover, these blood-borne proteins cluster with the amyloid beta plaque in the brain, exacerbating microglial activation, neuroinflammation, tau phosphorylation, and oxidative stress. These mechanisms work in concert and reinforce each other, contributing to the typical pathological changes in AD in the brain. Therefore, the identification of blood-borne proteins and the mechanisms involved in microglial activation and neuroinflammatory damage can be a promising therapeutic strategy for AD prevention. In this article, we review the current knowledge regarding the mechanisms of microglial activation-mediated neuroinflammation caused by the influx of blood-borne proteins into the brain via BBB disruption. Subsequently, the mechanisms of drugs that inhibit blood-borne proteins, as a potential therapeutic approach for AD, along with the limitations and potential challenges of these approaches, are also summarized.

Oral direct thrombin inhibitors or oral factor Xa inhibitors versus conventional anticoagulants for the treatment of pulmonary embolism

BACKGROUND

Pulmonary embolism (PE) is a potentially life-threatening condition in which a clot can migrate from the deep veins, most commonly in the leg, to the lungs. Conventional treatment of PE used unfractionated heparin (UFH), low molecular weight heparin (LMWH), fondaparinux, and vitamin K antagonists (VKAs). Recently, two forms of direct oral anticoagulants (DOACs) have been developed: oral direct thrombin inhibitors (DTIs) and oral factor Xa inhibitors. DOACs have characteristics that may be favourable to conventional treatment, including oral administration, a predictable effect, no need for frequent monitoring or re-dosing, and few known drug interactions. This review reports the efficacy and safety of these drugs in the long-term treatment of PE (minimum duration of three months). This is an update of a Cochrane Review first published in 2015.  OBJECTIVES: To assess the efficacy and safety of oral DTIs and oral factor Xa inhibitors versus conventional anticoagulants for the long-term treatment of PE.

SEARCH METHODS

The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE, Embase and CINAHL databases, the World Health Organization International Clinical Trials Registry Platform and the ClinicalTrials.gov trials registers to 2 March 2022. We checked the reference lists of relevant articles for additional studies.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) in which people with a PE confirmed by standard imaging techniques were allocated to receive an oral DTI or an oral factor Xa inhibitor compared with a conventional anticoagulant or compared with each other for the long-term treatment of PE (minimum duration three months).

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Our primary outcomes were recurrent PE, recurrent venous thromboembolism (VTE), and deep vein thrombosis (DVT). Secondary outcomes were all-cause mortality, major bleeding, and health-related quality of life. We used GRADE to assess the certainty of evidence for each outcome.

MAIN RESULTS

We identified five additional RCTs with 1484 participants for this update. Together with the previously included trials, we have included ten RCTs with a total of 13,073 participants. Two studies investigated an oral DTI (dabigatran) and eight studies investigated oral factor Xa inhibitors (three rivaroxaban, three apixaban, and two edoxaban). The studies were of good methodological quality overall.  Meta-analysis showed no clear difference in the efficacy and safety of oral DTI compared with conventional anticoagulation in preventing recurrent PE (odds ratio (OR) 1.02, 95% confidence interval (CI) 0.50 to 2.04; 2 studies, 1602 participants; moderate-certainty evidence), recurrent VTE (OR 0.93, 95% CI 0.52 to 1.66; 2 studies, 1602 participants; moderate-certainty evidence), DVT (OR 0.79, 95% CI 0.29 to 2.13; 2 studies, 1602 participants; moderate-certainty evidence), and major bleeding (OR 0.50, 95% CI 0.15 to 1.68; 2 studies, 1527 participants; moderate-certainty evidence). We downgraded the certainty of evidence by one level for imprecision due to the low number of events. There was also no clear difference between the oral factor Xa inhibitors and conventional anticoagulation in the prevention of recurrent PE (OR 0.92, 95% CI 0.66 to 1.29; 3 studies, 8186 participants; moderate-certainty evidence), recurrent VTE (OR 0.83, 95% CI 0.66 to 1.03; 8 studies, 11,416 participants; moderate-certainty evidence), DVT (OR 0.77, 95% CI 0.48 to 1.25; 2 studies, 8151 participants; moderate-certainty evidence), all-cause mortality (OR 1.16, 95% CI 0.79 to 1.70; 1 study, 4817 participants; moderate-certainty evidence) and major bleeding (OR 0.71, 95% CI 0.36 to 1.41; 8 studies, 11,447 participants; low-certainty evidence); the heterogeneity for major bleeding was significant (I2 = 79%). We downgraded the certainty of the evidence to moderate and low because of imprecision due to the low number of events and inconsistency due to clinical heterogeneity. None of the included studies measured health-related quality of life.

AUTHORS' CONCLUSIONS

Available evidence shows there is probably little or no difference between DOACs and conventional anticoagulation in the prevention of recurrent PE, recurrent VTE, DVT, all-cause mortality, and major bleeding. The certainty of evidence was moderate or low. Future large clinical trials are required to identify if individual drugs differ in effectiveness and bleeding risk, and to explore effect differences in subgroups, including people with cancer and obesity.

Pulsed laser irradiation induces the generation of alloy cluster ions for the screening of protease activity

Pulsed laser irradiation can cause the fragmentation of nanoparticles, which generates cluster ions. This allows nanoparticles to be adopted as mass tag/signal amplifiers in laser desorption/ionization mass spectrometry (LDI-MS) bioassays. Herein, we demonstrate the potential of using the signal from alloy cluster ions in bioassays through a fibrin clot model to determine the activity of thrombin. A mixed solution of silver and gold nanoparticles functionalized with fibrinogen (Fg‒Ag NPs/Fg‒Au NPs) treated with thrombin can form clots composed of aggregated fibrin-Au NPs/Ag NPs. These clots analyzed with LDI-MS are noted to form intense Ag-Au alloy cluster ions, especially [Ag₂Au]⁺, which were used to detect thrombin concentration with a dynamic range of 2.5-50 pM in human plasma. This sensing platform was further employed for the screening of direct thrombin inhibitors. This work developed a novel bioassay utilizing metallic gas-phase reactions generated from pulsed laser irradiation of aggregated nanoparticles to monitor enzymatic activity and to screen inhibitors. We believe that LDS-MS can serve as a new platform for gas-phase reaction-based bioassays.

Methods to Correct Drug-Induced Coagulopathy in Bleeding Emergencies: A Comparative Review

OBJECTIVE

Anticoagulant and antiplatelet therapy have become increasingly popular. The goal of therapy is to prevent venous thromboembolism and platelet aggregation, respectively. Traditional anticoagulant and antiplatelet drugs are quickly being replaced with novel medications with more predictable pharmacokinetics. Unfortunately, these drugs carry the risk of uncontrolled hemorrhage because of drug-induced coagulopathy. Uncontrolled hemorrhage continues to be a major cause of preventable death: hemorrhage accounts for approximately 30% of trauma-related deaths, second to brain injury. Controlling hemorrhage while dealing with comorbidities remains a challenge to clinicians. There are many gaps in care and knowledge that contribute to the struggle of treating this patient population.

METHODS

This literature review is focused on the most effective ways to achieve hemostasis in a patient with drug-induced coagulopathy. The antiplatelet therapies aspirin, clopidogrel, ticlopidine, pasugrel, and ticagrelor are analyzed. Anticoagulant therapies are also reviewed, including warfarin, rivaroxaban, apixaban, edoxaban, and dabigatran. In addition, viscoelastic testing and platelet function assays are reviewed for their ability to monitor drug effectiveness and to accurately depict the patient's ability to clot. This review focuses on articles from the past 10 years. However, there are limitations to the 10-year restriction, including no new research posted within the 10-year timeline on particular subjects. The most recent article was then used where current literature did not exist (within 10 years).

RESULTS

Traditional anticoagulants have unpredictable pharmacokinetics and can be difficult to correct in bleeding emergencies. Vitamin K has been proven to reliably and effectively reverse the effect of vitamin K antagonists (VKAs) while having a lower anaphylactoid risk than frozen plasma. Prothrombin complex concentrates should be used when there is risk of loss of life or limb. Frozen plasma is not recommended as a first-line treatment for the reversal of VKAs. Novel anticoagulants have specific reversal agents such as idarucizumab for dabigatran and andexxa alfa for factor Xa (FXa) inhibitors. Although reliable, these drugs carry a large price tag. As with traditional anticoagulants, cheaper alternative therapies are available such as prothrombin complex concentrates. Finally, static coagulation testing works well for routine therapeutic drug monitoring but may not be appropriate during bleeding emergencies. Viscoelastic testing such as thromboelastography and rotational thromboelastometry depict in vivo hemostatic properties more accurately than static coagulation assays. Adding viscoelastic testing into resuscitation protocols may guide blood product usage more efficiently.

CONCLUSION

This review is intended to be used as a guide. The topics covered in this review should be used as a reference for treating the conditions described. This review article also covers laboratory testing and is meant as a guide for physicians on best practices. These findings illustrate recommended testing and reversal techniques based off evidence-based medicine and literature.

Factors Influencing the Selection of Non-Vitamin K Antagonist Oral Anticoagulants for Stroke Prevention in Patients With Non-Valvular Atrial Fibrillation

BACKGROUND

Major atrial fibrillation (AF) guidelines recommend non-vitamin K antagonist oral anticoagulants (NOACs) over warfarin, except in rare clinical circumstances based on 4 randomized controlled trials comparing each NOAC with warfarin. We aimed to investigate the current NOAC prescription behaviors in alignment with the recent clinical evidence available.

METHOD

We conducted a cross-sectional analysis of NOAC-using patients with non-valvular atrial fibrillation (NVAF) who were aged ≥65 years on the index date (July 1, 2018) based on nationwide claims data. The types of NOACs being taken were analyzed using chi-squared tests, and factors influencing NOAC selection were identified using multinomial logistic regression analysis.

RESULTS

A total of 6,061 patients were included. Among the 4 NOACs, rivaroxaban was the most used NOAC. Patients aged ≥75 years (odds ratio [OR] = 1.270, confidence interval [CI] = 1.089-1.450) and women (OR = 1.148, CI = 1.011-1.284) were more likely to use apixaban relative to rivaroxaban. Patients with prior stroke/transient ischemic attack/thromboembolism had higher odds of using dabigatran (OR = 1.508, CI = 1.312-1.704) and apixaban (OR = 1.186, CI = 1.026-1.346). Patients with renal disease had higher odds of using apixaban (OR = 1.466, 95% CI = 1.238-1.693). These findings are consistent with the efficacy and safety profiles reported in pivotal trials and observational studies comparing individual NOACs.

CONCLUSION

Among the 4 NOACs, rivaroxaban was the most commonly used NOAC. Apixaban was preferred for patients aged ≥75 years, females, and patients with renal disease.

Review of Direct Oral Anticoagulants and Guide for Effective Drug Utilization

Direct oral anticoagulants (DOACs) have been developed as a viable and in some cases superior alternative to warfarin. These agents have overcome some of the limitations of warfarin, which has a narrow therapeutic window and many food and drug interactions. DOACs have been demonstrated to have a more predictable and reliable pharmacology and, unlike warfarin, do not require frequent monitoring of anticoagulant effect. For these reasons, the use of DOACs is increasing. Despite the many positive attributes of these agents, limitations and contraindications do exist. An understanding of the pharmacology, indications, and contraindications is therefore crucial for effective patient management. We review the available agents to aid in effective drug utilization.

Bilateral subconjunctival hemorrhage secondary to abciximab use: case report

CONTEXT

There are no reports on cases of subconjunctival hemorrhage due to use of glycoprotein IIb/IIIa inhibitors. In this report, we present the case of a patient with bilateral subconjunctival hemorrhage after receiving abciximab.

CASE REPORT

A 40-year-old male patient underwent coronary angiography after acute anterior myocardial infarction and a coronary stent was placed. Abciximab was added to the therapy because of stent thrombosis. Bilateral subconjunctival hemorrhage was observed after the administration of the abciximab treatment. We treated our patient by stopping abciximab and administering artificial tears.

CONCLUSİON

For the first time in the literature, we presented the case of a patient with bilateral subconjunctival hemorrhage after receiving abciximab, which was managed conservatively.

Comparison of dabigatran and warfarin used in patients with non-valvular atrial fibrillation: Meta-analysis of random control trial

BACKGROUND

Dabigatran is a kind of oral anticoagulant and there was little review only about dabigatran and warfarin used in patients with atrial fibrillation. This meta-analysis only assesses the dabigatran and warfarin used in patients with atrial fibrillation.

DESIGN

Cochrane Library, PubMed, Clinical Trials.gov, CNKI, and WanFang databases were searched. The primary endpoint was the incidence of stroke and the second endpoints were the incidence of bleeding and embolic events.

RESULTS

Six RCTs and 20086 patients were included in our meta-analysis. No significant difference was obtained between 110 mg dabigatran and warfarin on the endpoint of stroke (risk ratio (RR), 0.90; 95% confidence interval [CI], 0.71-1.12; P = .34; I = 0%) and embolic events p (RR, 0.89; 95% CI, 0.71-1.12; P = .32; I = 0%). However, the 110 mg dabigatran associated lower incidence of bleeding (RR, 0.81; 95% CI, 0.69-0.95; P = .01; I = 0%) compare with warfarin. When compared with 150 mg dabigatran, warfarin associated with lower rate of stroke (RR, 0.96; 95% CI, 0.83-1.12; P = .62; I = 0%) and embolic events (RR, 0.67; 95% CI, 0.53-0.86; P = .001; I = 0%) but similar in the incidence of bleeding (RR, 0.67; 95% CI, 0.53-0.86; P = .001; I = 0%).

CONCLUSION

No significant difference was obtained between 110 mg dabigatran and warfarin in the incidence of stroke and embolic events. However, the 110 mg dabigatran associated lower incidence of bleeding compare with warfarin. When compared with 150 mg dabigatran, warfarin associated with lower incidence of stroke and embolic events but similar in the incidence of bleeding.

The perioperative management of new direct oral anticoagulants: a question without answers

New direct oral anticoagulant agents (DOAC) are currently licensed for thromboprophylaxis after hip and knee arthroplasty and for longterm prevention of thromboembolic events in non-valvular atrial fibrillation as well as treatment and secondary prophylaxis of venous thromboembolism. Some other medical indications are emerging. Thus, anaesthesiologists are increasingly likely to encounter patients on these drugs who need elective or emergency surgery. Due to the lack of experience and data, the management of DOAC in the perioperative period is controversial. In this article, we review available information and recommendations regarding the periprocedural management of the currently most clinically developed DOAC, apixaban, dabigatran, and rivaroxaban. We discuss two trends of managing patients on DOAC for elective surgery. The first is stopping the DOAC 1–5 days before surgery (depending on the drug, patient and bleeding risk) without bridging. The second is stopping the DOAC 5 days preoperatively and bridging with low-molecular-weight heparin. The management of patients on DOAC needing emergency surgery is also reviewed. As no data exist for the use of haemostatic products for the reversal of the anticoagulant effect in these cases, rescue treatment recommendations are proposed.

Increased Thromboembolic Events With Dabigatran Compared With Vitamin K Antagonism in Left Ventricular Assist Device Patients: A Randomized Controlled Pilot Trial

Supplemental Digital Content is available in the text.

Background—

Left ventricular assist device–supported patients are usually anticoagulated with a combination of aspirin and vitamin K antagonists. Long-term vitamin K antagonist therapy can be complicated by unstable international normalized ratio values and patient-related compliance problems. Therefore, direct thrombin inhibitors may represent an alternative to vitamin K antagonists.

Methods and Results—

Thirty HeartWare ventricular assist device patients with stable renal function were planned for this prospective, randomized, open-label, single-center study. Patients were randomized to receive either phenprocoumon or dabigatran in addition to aspirin for long-term anticoagulation. Treatment duration was scheduled for 1 year and stopped after observation of a primary end point. Dabigatran dose was 110 and 75 mg BID in patients with normal or impaired renal function (glomerular filtration rate >80 mL/min or between 80 and 30 mL/min, respectively). The study was stopped prematurely for safety reasons after 16 patients (61±8 years, 1 female) were randomized. Thromboembolic events occurred in 4 subjects receiving dabigatran (50%) and in 1 receiving phenprocoumon (13%; P=0.28). No major bleeding was recorded, and no patient died during the study. Median time to treatment termination was significantly shorter in dabigatran patients (8.5 versus 12.0 months; P=0.015).

Conclusions—

Thromboembolic events on dabigatran led to early termination of a randomized controlled trial of dabigatran versus phenprocoumon in left ventricular assist device patients.

Clinical Trial Registration—

https://www.clinicaltrials.gov. Unique identifier: NCT02872649.

Thrombin Receptor Agonist Peptide-Induced Platelet Aggregation Is Reduced in Patients Receiving Dabigatran

The availability of direct oral anticoagulants has caused a paradigm shift in thrombosis management. The direct thrombin inhibitor dabigatran seems to obstruct tenase complex by inhibiting thrombin generated in the initial phase and feed back to the amplification phase of cell-based coagulation reactions. However, it is still not fully understood if and how dabigatran impact platelet function. This observational study aimed to assess in vitro platelet function in patients with atrial fibrillation receiving dabigatran. Platelet aggregability was tested with platelet-rich plasma using platelet aggregometry (PACKS-4 aggregometer). Blood samples were stimulated with thrombin receptor agonist peptide (TRAP; 32 μmol/L).

RESULTS

A total of 28 patients with nonvalvular atrial fibrillation were enrolled. The mean age was 71.57 (9.75) years (range: 50-87 years), 16 patients were women, and the mean CHA₂DS₂VASc score was 3.93 (1.41). All patients began treatment with dabigatran as initial anticoagulant treatment. The minimum term use of dabigatran was 18 days. Dabigatran doses were 110 mg (57.14%) or 150 mg (42.86%) twice daily. The TRAP-induced platelet aggregation was significantly lower 2 hours after taking dabigatran compared to baseline value (79.39 [13.38] vs 90.14 [10.5]).

CONCLUSION

The TRAP-induced platelet aggregation was reduced in cardiovascular patients 2 hours after receiving dabigatran. Our findings could have some important clinical implications because platelet aggregation and coagulation cascade are affected at the same time.

Comparative Efficacy of Clinical Events Prevention of Five Anticoagulants in Patients With Atrial Fibrillation (A Network Meta-Analysis)

Atrial fibrillation (AF) ranks the most prevailing type of cardiac rhythm disorder and AF patients are associated with a significantly increased risk of stroke compared to others. This study is designed to assess the relative efficacy of several clinical events prevention anticoagulants in patients with AF. Conventional pairwise meta-analysis was performed with fixed-effect model initially, then network meta-analysis was performed with random-effects model within results illustrated by cumulative odds ratios (ORs) and corresponding 95% credible interval (CrI). The rank probabilities of each treatment outcomes were summarized by the surface under the cumulative ranking curve (SUCRA). We conducted a systematic review and collected key clinical data from 37 studies with respect to 5 anticoagulant treatments for AF. Patients treated with rivaroxaban and apixaban are associated with a reduced risk of stroke compared to those treated with warfarin (OR 0.72, 95% CrI 0.53 to 0.88; OR 0.68, 95% CrI 0.48 to 0.91). Rivaroxaban (SUCRA = 0.712) appears to be the most preferable one with respect to vascular events, and both apixaban (SUCRA = 0.720) and rivaroxaban (SUCRA = 0.678) are preferable to others with respect to stroke. Dabigatran outperforms others with respect to the outcome of mortality (SUCRA = 0.695), hemorrhage events (SUCRA = 0.747), and myocardial infarction (SUCRA = 0.620). In conclusion, dabigatran has a noticeable and comprehensive advantage compared to others with respect to preventing several complications including hemorrhage events, myocardial infarction, and mortality. In addition, apixaban may be the best choice of preventing stroke, and rivaroxaban is more preferable to others with respect to preventing vascular events.

Recent Advances in the Pharmacological Management of Atrial Fibrillation

Atrial fibrillation (AF) is a highly prevalent cardiac arrhythmia that leads to hospitalizations for complications and adverse events each year. Despite significant improvement in our therapeutic approaches in the past decade, management of AF remains a difficult task. Novel therapies have failed to terminate AF and prevent its recurrence, and patients with AF continue to have thromboembolic complications. With the increasingly aging population and associated conditions, the prevalence of AF is expected to progressively increase, becoming a public health problem. Most patients with AF have multiple comorbidities and are of advanced age, making long-term anticoagulation challenging. This article provides an overview of the current pharmacological therapies for the management of AF, with particular emphasis on the emerging agents.

Treatment of Venous Thromboembolism With New Anticoagulant Agents

Venous thromboembolism (VTE) is a common disease associated with high risk for recurrences, death, and late sequelae, accounting for substantial health care costs. Anticoagulant agents are the mainstay of treatment for deep vein thrombosis and pulmonary embolism. The recent availability of oral anticoagulant agents that can be administered in fixed doses, without laboratory monitoring and dose adjustment, is a landmark change in the treatment of VTE. In Phase III trials, rivaroxaban, apixaban, edoxaban (antifactor Xa agents), and dabigatran (an antithrombin agent) were noninferior and probably safer than conventional anticoagulation therapy (low-molecular-weight heparin followed by vitamin K antagonists). These favorable results were confirmed in specific patient subgroups, such as the elderly and fragile. However, some patients, such as those with cancer or with intermediate- to high-risk pulmonary embolism, were underrepresented in the Phase III trials. Further clinical research is required before new oral anticoagulant agents can be considered standard of care for the full spectrum of patients with VTE.

The modification of the thrombin generation test for the clinical assessment of dabigatran etexilate efficiency

A new oral anticoagulant, dabigatran etexilate (DE, a prodrug of direct thrombin inhibitor (DTI) dabigatran), has been used clinically to prevent thrombosis. The assessment of dabigatran efficiency is necessary in some clinical cases, such as renal insufficiency, risk of bleeding, and drug interactions. However, a specific thrombin generation test (TGT) that is one of the most informative and sensitive to anticoagulant therapy (calibrated automated thrombinography (САТ)) shows a paradoxical increase of test parameters, such as endogenous thrombin potential (ETP) and peak thrombin, in patients receiving DE. The paradoxical behaviour of ETP and peak thrombin in these patients in the presence of DTIs is mostly caused by a decrease in the activity of thrombin in the α₂-macroglobulin-thrombin complex that is used as a calibrator in CAT. For a correct estimation of the TGT parameters in patient’s plasma containing DTIs we proposed to use our previously described alternative calibration method that is based on the measurement of the fluorescence signal of a well-known concentration of the reaction product (7-amino-4-methylcoumarin). In this study, the validity of such approach was demonstrated in an ex vivo study in patients with knee replacement and two special patients with multiple myeloma, who received DE for thrombosis prophylaxis.

Use of Continuous Renal Replacement Therapy for Removal of Dabigatran in a Patient in Need of Emergent Surgery

Purpose. To report the ability to remove serum dabigatran using continuous renal replacement therapy (CRRT) in a patient with life-threatening bleeding. Summary. A 77-year-old female with history of atrial fibrillation who takes dabigatran for stroke prevention presented with abdominal pain. Patient was found to have bleeding and possible mesenteric ischemia and was taken to the operating room and had continued bleeding postoperatively. CRRT was initiated for the removal of any remaining dabigatran, with serum dabigatran levels collected to evaluate removal of dabigatran with CRRT. This patient had an increased dabigatran level prior to intervention, which decreased to an undetectable level after use of CRRT. Greater than 80% of the drug was removed due to 4 hours of CRRT and residual kidney function. Reversal of dabigatran is an area of current research with recent FDA approval of idarucizumab for use. Conclusion. Bleeding may occur as a result of the use of dabigatran and change in patient's clinical condition. Use of CRRT may be an option in removing serum dabigatran in the case of a life-threatening bleed.

Oral direct thrombin inhibitors or oral factor Xa inhibitors for the treatment of pulmonary embolism

BACKGROUND

Pulmonary embolism is a potentially life-threatening condition in which a clot can travel from the deep veins, most commonly in the leg, up to the lungs. Previously, a pulmonary embolism was treated with the anticoagulants heparin and vitamin K antagonists. Recently, however, two forms of direct oral anticoagulants (DOACs) have been developed: oral direct thrombin inhibitors (DTI) and oral factor Xa inhibitors. The new drugs have characteristics that may be favourable over conventional treatment, including oral administration, a predictable effect, lack of frequent monitoring or re-dosing and few known drug interactions. To date, no Cochrane review has measured the effectiveness and safety of these drugs in the long-term treatment (minimum duration of three months) of pulmonary embolism.

OBJECTIVES

To assess the effectiveness of oral DTIs and oral factor Xa inhibitors for the long-term treatment of pulmonary embolism.

SEARCH METHODS

The Cochrane Vascular Trials Search Co-ordinator searched the Specialised Register (last searched January 2015) and the Cochrane Register of Studies (last searched January 2015). Clinical trials databases were also searched for details of ongoing or unpublished studies. We searched the reference lists of relevant articles retrieved by electronic searches for additional citations.

SELECTION CRITERIA

We included randomised controlled trials in which patients with a pulmonary embolism confirmed by standard imaging techniques were allocated to receive an oral DTI or an oral factor Xa inhibitor for the long-term (minimum duration three months) treatment of pulmonary embolism.

DATA COLLECTION AND ANALYSIS

Two review authors (LR, JM) independently extracted the data and assessed the risk of bias in the trials. Any disagreements were resolved by discussion with the third author (PK). We used meta-analyses when we considered heterogeneity low. The two primary outcomes were recurrent venous thromboembolism and pulmonary embolism. Other outcomes included all-cause mortality and major bleeding. We calculated all outcomes using an odds ratio (OR) with a 95% confidence interval (CI).

MAIN RESULTS

We included five randomised controlled trials with a total of 7897 participants. Two studies tested oral DTIs (dabigatran) and three studies tested oral factor Xa inhibitors (one rivaroxaban, one edoxaban and one apixaban).Analysis showed no difference in the effectiveness of oral DTIs and standard anticoagulation in preventing recurrent pulmonary embolism (OR 1.02, 95% CI 0.50 to 2.04; two studies; 1602 participants; high quality evidence), recurrent venous thromboembolism (OR 0.93, 95% CI 0.52 to 1.66; two studies; 1602 participants; high quality evidence), deep vein thrombosis (DVT) (OR 0.79, 95% CI 0.29 to 2.13; two studies; 1602 participants; high quality evidence) and major bleeding (OR 0.50, 95% CI 0.15 to 1.68; two studies; 1527 participants; high quality evidence).For oral factor Xa inhibitors, when we combined the three included studies together in meta-analyses, there was significant heterogeneity for recurrent pulmonary embolism (OR 1.08, 95% CI 0.46 to 2.56; two studies; 4509 participants; I(2) = 58%; moderate quality evidence). The oral factor Xa inhibitors were no more or less effective in the prevention of recurrent venous thromboembolism (OR 0.85, 95% CI 0.63 to 1.15; three studies; 6295 participants; high quality evidence), DVT (OR 0.72, 95% CI 0.39 to 1.32; two studies; 4509 participants; high quality evidence), all-cause mortality (OR 1.16, 95% CI 0.79 to 1.70; one study; 4817 participants; moderate quality evidence) or major bleeding (OR 0.97, 95% CI 0.59 to 1.62; two studies; 4507 participants; high quality evidence). None of the studies measured quality of life.

AUTHORS' CONCLUSIONS

Moderate to high quality evidence suggests that there are no differences between DOACs and standard anticoagulation for the long-term treatment of pulmonary embolism, for the outcomes recurrent pulmonary embolism, recurrent venous thromboembolism, DVT, all-cause mortality and major bleeding.

Oral direct thrombin inhibitors or oral factor Xa inhibitors for the treatment of deep vein thrombosis

BACKGROUND

Deep vein thrombosis (DVT) is a condition in which a clot forms in the deep veins, most commonly of the leg. It occurs in approximately 1 in 1,000 people. If left untreated, the clot can travel up to the lungs and cause a potentially life-threatening pulmonary embolism (PE). Previously, a DVT was treated with the anticoagulants heparin and vitamin K antagonists. However, two forms of novel oral anticoagulants (NOACs) have been developed: oral direct thrombin inhibitors (DTI) and oral factor Xa inhibitors. The new drugs have characteristics that may be favourable over conventional treatment, including oral administration, a predictable effect, lack of frequent monitoring or re-dosing and few known drug interactions. To date, no Cochrane review has measured the effectiveness and safety of these drugs in the treatment of DVT.

OBJECTIVES

To assess the effectiveness of oral DTIs and oral factor Xa inhibitors for the treatment of DVT.

SEARCH METHODS

The Cochrane Peripheral Vascular Diseases Group Trials Search Co-ordinator searched the Specialised Register (last searched January 2015) and the Cochrane Register of Studies (last searched January 2015). We searched clinical trials databases for details of ongoing or unpublished studies and the reference lists of relevant articles retrieved by electronic searches for additional citations.

SELECTION CRITERIA

We included randomised controlled trials in which people with a DVT confirmed by standard imaging techniques, were allocated to receive an oral DTI or an oral factor Xa inhibitor for the treatment of DVT.

DATA COLLECTION AND ANALYSIS

Two review authors (LR, JM) independently extracted the data and assessed the risk of bias in the trials. Any disagreements were resolved by discussion with the third review author (PK). We performed meta-analyses when we considered heterogeneity low. The two primary outcomes were recurrent VTE and PE. Other outcomes included all-cause mortality and major bleeding. We calculated all outcomes using an odds ratio (OR) with a 95% confidence interval (CI).

MAIN RESULTS

We included 11 randomised controlled trials of 27,945 participants. Three studies tested oral DTIs (two dabigatran and one ximelagatran), while eight tested oral factor Xa inhibitors (four rivaroxaban, two apixaban and two edoxaban). We deemed all included studies to be of high methodological quality and low risk of bias. The quality of the evidence was graded as high as the outcomes were direct and effect estimates were consistent and precise, as reflected in the narrow CIs around the ORs. Meta-analysis of three studies (7596 participants) comparing oral DTIs with standard anticoagulation groups showed no difference in the rate of recurrent VTE (OR 1.09; 95% CI 0.80 to 1.49), recurrent DVT (OR 1.08; 95% CI 0.74 to 1.58), fatal PE (OR 1.00; 95% CI 0.27 to 3.70), non-fatal PE (OR 1.12; 95% CI 0.66 to 1.90) or all-cause mortality (OR 0.82; 95% CI 0.60 to 1.13). However, oral DTIs were associated with reduced bleeding (OR 0.68; 95% CI 0.47 to 0.98). Meta-analysis of eight studies (16,356 participants) comparing oral factor Xa inhibitors with standard anticoagulation demonstrated a similar rate of recurrent VTE between the two treatments (OR 0.89; 95% CI 0.73 to 1.07). Oral factor Xa inhibitors were associated with a lower rate of recurrent DVT (OR 0.75; 95% CI 0.57 to 0.98). However, this was a weak association, heavily dependent on one study. The rate of fatal (OR 1.20; 95% CI 0.71 to 2.03), non-fatal PE (OR 0.94; 95% CI 0.68 to 1.28) and all-cause mortality (OR 0.90; 95% CI 0.65 to 1.23) was similar between the two treatment groups. Oral factor Xa inhibitors were also associated with reduced bleeding (OR 0.57; 95% CI 0.43 to 0.76). None of the included studies measured post-thrombotic syndrome or health-related quality of life.

AUTHORS' CONCLUSIONS

NOACs such as DTIs and factor Xa inhibitors may be an effective and safe alternative to conventional anticoagulation treatment for acute DVT.

Pharmacist-managed clinics for patient education and counseling in Japan: current status and future perspectives

To improve the adherence to and knowledge about pharmacotherapy in outpatients and to maximize the efficacy and minimize the adverse drug events, the first pharmacist-managed clinic (PMC) in Japan was established for anticoagulation therapy at Nagoya University Hospital in 2000. Since then, various PMCs such as for asthma/chronic obstructive pulmonary disease, Alzheimer's disease, hypercholesterolemia, chronic hepatitis C, cancer chemotherapy, palliative care, chronic kidney disease, and continuous ambulatory peritoneal dialysis have been established and expanded to many hospitals in Japan. Accumulating evidences suggest that PMCs have some beneficial effects on patients' adherence to and knowledge about their pharmacotherapy as well as the clinical outcome, besides being cost-effective. Notably, PMCs for cancer chemotherapy have been approved as a new medical service in hospitals in 2014, which is covered by the universal health coverage in Japan. In this review article, the current status of PMCs for patient education and counseling in Japan and their impact on pharmaceutical care and management are critically reviewed. Furthermore, future perspectives on PMCs are discussed.

Direct thrombin inhibitors versus vitamin K antagonists for preventing cerebral or systemic embolism in people with non-valvular atrial fibrillation

BACKGROUND

Chronic anticoagulation with vitamin K antagonists (VKAs) prevents ischaemic stroke and systemic embolism in people with non-valvular atrial fibrillation (AF) but dose adjustment, coagulation monitoring and bleeding limits its use. Direct thrombin inhibitors (DTIs) are under investigation as potential alternatives.

OBJECTIVES

To assess (1) the comparative efficacy of long-term anticoagulation using DTIs versus VKAs on vascular deaths and ischaemic events in people with non-valvular AF, and (2) the comparative safety of chronic anticoagulation using DTIs versus VKAs on (a) fatal and non-fatal major bleeding events including haemorrhagic strokes, (b) adverse events other than bleeding and ischaemic events that lead to treatment discontinuation and (c) all-cause mortality in people with non-valvular AF.

SEARCH METHODS

We searched the Cochrane Stroke Group Trials Register (July 2013), the Cochrane Central Register of Controlled Trials (CENTRAL), (The Cochrane Library, May 2013), MEDLINE (1950 to July 2013), EMBASE (1980 to October 2013), LILACS (1982 to October 2013) and trials registers (September 2013). We also searched the websites of clinical trials and pharmaceutical companies and handsearched the reference lists of articles and conference proceedings.

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing DTIs versus VKAs for prevention of stroke and systemic embolism in people with non-valvular AF.

DATA COLLECTION AND ANALYSIS

All three review authors independently performed data extraction and assessment of risk of bias. Primary analyses compared all DTIs combined versus warfarin. We performed post hoc analyses excluding ximelagatran because this drug was withdrawn from the market owing to safety concerns.

MAIN RESULTS

We included eight studies involving a total of 27,557 participants with non-valvular AF and one or more risk factors for stroke; 26,601 of them were assigned to standard doses groups and included in the primary analysis. The DTIs: dabigatran 110 mg twice daily and 150 mg twice daily (three studies, 12,355 participants), AZD0837 300 mg once per day (two studies, 233 participants) and ximelagatran 36 mg twice per day (three studies, 3726 participants) were compared with the VKA warfarin (10,287 participants). Overall risk of bias and statistical heterogeneity of the studies included were low.The odds of vascular death and ischaemic events were not significantly different between all DTIs and warfarin (odds ratio (OR) 0.94, 95% confidence interval (CI) 0.85 to 1.05). Sensitivity analysis by dose of dabigatran on reduction in ischaemic events and vascular mortality indicated that dabigatran 150 mg twice daily was superior to warfarin although the effect estimate was of borderline statistical significance (OR 0.86, 95% CI 0.75 to 0.99). Sensitivity analyses by other factors did not alter the results. Fatal and non-fatal major bleeding events, including haemorrhagic strokes, were less frequent with the DTIs (OR 0.87, 95% CI 0.78 to 0.97). Adverse events that led to discontinuation of treatment were significantly more frequent with the DTIs (OR 2.18, 95% CI 1.82 to 2.61). All-cause mortality was similar between DTIs and warfarin (OR 0.91, 95% CI 0.83 to 1.01).

AUTHORS' CONCLUSIONS

DTIs were as efficacious as VKAs for the composite outcome of vascular death and ischaemic events and only the dose of dabigatran 150 mg twice daily was found to be superior to warfarin. DTIs were associated with fewer major haemorrhagic events, including haemorrhagic strokes. Adverse events that led to discontinuation of treatment occurred more frequently with the DTIs. We detected no difference in death from all causes.

New anticoagulants and antiplatelet agents: a primer for the clinical gastroenterologist

The discovery of the first oral anticoagulant, warfarin, was a milestone in anticoagulation. Warfarin's well-known limitations, however, have led to the recent development of more effective anticoagulants. The rapidly growing list of these drugs, however, presents a challenge to endoscopists who must treat patients on these sundry medications. This review is intended to summarize the pharmacological highlights of new anticoagulants, with particular attention to suggested "best-practice" recommendations for the withholding of these drugs before endoscopic procedures.

Risk assessment for recurrence and optimal agents for extended treatment of venous thromboembolism

Venous thromboembolism (VTE) has a variable recurrence rate after the discontinuation of anticoagulant treatment. Therefore, the duration of anticoagulation therapy after a first VTE should be tailored to the estimated risk for recurrence. Anticoagulant therapy should be discontinued after the initial 3 to 6 months in those patients who had the first episode in association with temporary risk factors. The duration of anticoagulant therapy in patients who had a first episode of cancer-associated VTE should be reassessed over time based on the persistence of cancer and anticancer therapy. After 3 to 6 months of anticoagulant treatment for VTE, patients with a first unprovoked event and an estimated low risk for bleeding complications should be evaluated for indefinite treatment on an individualized basis. New oral anticoagulants have been evaluated for the extended treatment of VTE. Large phase 3 studies have shown that dabigatran, rivaroxaban, and apixaban are effective and safe in this indication. These agents do not require monitoring for dose adjustment and could make extended treatment more feasible and acceptable to patients.

Oral bioavailability of dabigatran etexilate (Pradaxa(®) ) after co-medication with verapamil in healthy subjects

AIM

To investigate the effect of the P-glycoprotein inhibitor verapamil on the pharmacokinetics and pharmacodynamics of dabigatran etexilate (DE).

METHOD

In this two part multiple crossover trial in 40 healthy subjects, DE 150 mg was given alone or with verapamil at different doses, duration of treatment (single vs. multiple dosing), formulations, and timings (before, concurrently or after DE). Primary pharmacokinetic endpoints were determined from concentrations of total dabigatran (unconjugated plus conjugated). Pharmacodynamic endpoints were determined from clotting time.

RESULTS

The greatest effect was observed with single dose verapamil 120 mg immediate release given 1 h before single dose DE. Geometric mean area under the plasma concentration curve [AUC(0,∞)] and maximum analyte concentration in the plasma (Cmax ) were increased by 143% [90% confidence interval (CI) 91, 208] and 179% (90% CI 115, 262), respectively. The effect was reduced to a 71% and 91% increase in AUC and Cmax , respectively, when DE was administered with verapamil 240 mg extended release. After multiple verapamil dosing, DE AUC(0,∞) and Cmax increases were 54% and 63%, respectively. However, DE given 2 h before verapamil increased DE AUC(0,∞) and Cmax by <20%. With regard to clotting prolongation, the dabigatran plasma concentration-effect relationship was generally not affected by the co-administration of verapamil. Concomitant administration of DE and verapamil did not reveal any unexpected safety findings.

CONCLUSION

Verapamil increased DE bioavailability, likely due to inhibition of P-glycoprotein. Our results suggest that an interaction between verapamil and DE can be minimized if DE is administered 2 h prior to verapamil.

Anticoagulants: A Review of the Pharmacology, Dosing, and Complications

Anticoagulants remain the primary strategy for the prevention and treatment of thrombosis. Unfractionated heparin, low molecular weight heparin, fondaparinux, and warfarin have been studied and employed extensively with direct thrombin inhibitors typically reserved for patients with complications or those requiring intervention. Novel oral anticoagulants have emerged from clinical development and are expected to replace older agents with their ease of use and more favorable pharmacodynamic profiles. Hemorrhage is the main concerning adverse event with all anticoagulants. With their ubiquitous use, it becomes important for clinicians to have a sound understanding of anticoagulant pharmacology, dosing, and toxicity.

Dabigatran - a case history demonstrating the need for comprehensive approaches to optimize the use of new drugs

BACKGROUND

There are potential conflicts between authorities and companies to fund new premium priced drugs especially where there are safety and/or budget concerns. Dabigatran, a new oral anticoagulant for the prevention of stroke in patients with non-valvular atrial fibrillation (AF), exemplifies this issue. Whilst new effective treatments are needed, there are issues in the elderly with dabigatran due to variable drug concentrations, no known antidote and dependence on renal elimination. Published studies have shown dabigatran to be cost-effective but there are budget concerns given the prevalence of AF. There are also issues with potentially re-designing anticoagulant services. This has resulted in activities across countries to better manage its use.

OBJECTIVE

To (i) review authority activities in over 30 countries and regions, (ii) use the findings to develop new models to better manage the entry of new drugs, and (iii) review the implications for all major stakeholder groups.

METHODOLOGY

Descriptive review and appraisal of activities regarding dabigatran and the development of guidance for groups through an iterative process.

RESULTS

There has been a plethora of activities among authorities to manage the prescribing of dabigatran including extensive pre-launch activities, risk sharing arrangements, prescribing restrictions, and monitoring of prescribing post-launch. Reimbursement has been denied in some countries due to concerns with its budget impact and/or excessive bleeding. Development of a new model and future guidance is proposed to better manage the entry of new drugs, centering on three pillars of pre-, peri-, and post-launch activities.

CONCLUSION

Models for introducing new drugs are essential to optimize their prescribing especially where there are concerns. Without such models, new drugs may be withdrawn prematurely and/or struggle for funding.

Case report: dabigatran-associated gynecologic bleeding

PURPOSE

The case of a patient who experienced major gynecological bleeding after initiation of dabigatran therapy for atrial fibrillation is reported.

SUMMARY

A 33-year-old Hispanic female with multiple medical problems presented to the emergency department (ED) with a 5-day history of menorrhagia and a 3-day history of dizziness, fatigue, and weakness. Prior to ED presentation, she had been initiated on dabigatran 150 mg twice daily for atrial fibrillation. Four days later, she began having profuse vaginal bleeding. She discontinued all of her home medications including dabigatran, and her bleeding subsided the next day. Upon presentation to the ED, her hemoglobin was 7.1 g/dL, for which she was transfused 2 units of packed red blood cells, increasing her hemoglobin to 9.6 g/dL. Because the patient was in atrial fibrillation, warfarin was initiated once she was clinically stable and she was never restarted on dabigatran. Her hemoglobin was stable throughout admission with no further bleeding. She was discharged on warfarin and closely followed without incident.

CONCLUSION

A 33-year-old Hispanic female with no pre-existing gynecologic abnormalities had a major gynecological bleed shortly after starting dabigatran that resolved after discontinuation.

Effective elimination of dabigatran by haemodialysis. A phase I single-centre study in patients with end-stage renal disease

Dabigatran, a specific, reversible direct thrombin inhibitor, is used to prevent ischaemic and haemorrhagic strokes in patients with atrial fibrillation. As with every anticoagulant, there is a need to rapidly reverse its effects in emergency situations. In an open-label, single-centre phase I study with two fixed multiple dosing periods, we investigated the pharmacokinetics, pharmacodynamics and safety of dabigatran before, during and after 4 hour haemodialysis sessions with either 200 or 400 ml/min targeted blood flow in seven end-stage renal disease patients without atrial fibrillation. Dabigatran was administered over three days in a regimen designed to achieve peak plasma concentrations comparable to those observed in atrial fibrillation patients receiving 150 mg b.i.d. and to attain adequate distribution of dabigatran in the central and peripheral compartments. Plasma concentration-time profiles were similar in both periods on Day 3 (Cmax: 176 and 159 ng/ml). Four hours of haemodialysis removed 48.8% and 59.3% of total dabigatran from the central compartment with 200 and 400 ml/minute targeted blood flow, respectively. The anticoagulant activity of dabigatran was linearly related to its plasma levels. There was a minor redistribution of dabigatran (<16%) after the end of the haemodialysis session. In conclusion, a 4 hour haemodialysis session can rapidly eliminate a substantial amount of dabigatran from the central compartment with a concomitant marked reduction in its anticoagulant activity. There was a clinically negligible redistribution of dabigatran after haemodialysis. These results demonstrate that haemodialysis can be a suitable approach to eliminate dabigatran in emergency situations.

Epidural hematoma and intraoperative hemorrhage in a spine trauma patient on Pradaxa (dabigatran)

STUDY DESIGN

The authors present a case report of a 72-year-old man who presented with back pain and lower extremity weakness after a fall from his roof.

OBJECTIVE

Use of dabigatran (Pradaxa), a new oral anticoagulant, is rapidly increasing. Spine specialists should aware of this medication's place for the management of patients with spine pathology. In particular, we intend to report on the emergent treatment of a patient with spinal trauma and epidural hematoma with cord compression.

SUMMARY OF BACKGROUND DATA

Dabigatran (Pradaxa) is approved by the Food and Drug Administration to decrease stroke risk in patients with atrial fibrillation. Unlike warfarin, dabigatran does not require international normalized ratio monitoring. On the contrary, it is difficult to reverse in patients requiring emergent surgical intervention. METHODS.: This is a retrospective review of a patient treated at our institution.

RESULTS

The patient presented with burst fractures at the T7 and T12 levels. Cord compression was noted at both levels, and was worse at T12. Canal stenosis resulted from both retropulsed bone and epidural hematoma. The patient exhibited bilateral lower extremity numbness and weakness, ASIA C. The patient was taken urgently to the operating room for cord decompression and planned operative stabilization. The treating team used a number of recommended "reversal" agents with little effect on the severe intraoperative hemorrhage. Failure to control the bleeding required interruption of the procedure after the canal decompression. The patient was taken back to the operating room 7 days later for an instrumented posterior spinal fusion.

CONCLUSION

As dabigatran (Pradaxa) has recently been approved by the Food and Drug Administration, many spine specialists are not familiar with this agent. Many of the reversal agents (e.g., vitamin K and protamine), useful for other classes of anticoagulants, have no impact on Pradaxa. Similarly, prothrombin time and partial thromboplastin times have limited utility in estimating the patient's true clotting status. The purpose of this case report is to alert spine specialists to this drug and its implications on spine care. The drug's pharmacokinetics, clinical assessment of clotting status, and reversal options are discussed.

Anticoagulation Review

Anticoagulants, also known as antithrombotics, are among the most commonly prescribed medications in the United States. Understanding how these medications work, the propensity for interactions with other drugs, dietary factors, and disease states is important for clinicians assessing and providing care to patients in all environments. In this review, we seek to provide essential information for the home health care provider for evaluating patients receiving anticoagulants commonly prescribed in the home health care setting. The low-molecular-weight heparins and vitamin K antagonists are the most commonly used agents for outpatient anticoagulation. New agents, such as the direct factor Xa inhibitors and direct thrombin inhibitors have recently been approved with additional new agents in the approval process and development pipeline. We seek to review the most pertinent information for each of these classes of medications providing information on pharmacology, interactions with other drugs, diet, and diseases and important clinical information.

Costs and clinical consequences of suboptimal atrial fibrillation management

Atrial fibrillation (AF) places a considerable burden on the US health care system, society, and individual patients due to its associated morbidity, mortality, and reduced health-related quality of life. AF increases the risk of stroke, which often results in lengthy hospital stays, increased disability, and long-term care, all of which impact medical costs. An expected increase in the prevalence of AF and incidence of AF-related stroke underscores the need for optimal management of this disorder. Although AF treatment strategies have been proven effective in clinical trials, data show that patients still receive suboptimal treatment. Adherence to AF treatment guidelines will help to optimize treatment and reduce costs due to AF-associated events; new treatments for AF show promise for future reductions in disease and cost burden due to improved tolerability profiles. Additional research is necessary to compare treatment costs and outcomes of new versus existing agents; an immediate effort to optimize treatment based on existing evidence and guidelines is critical to reducing the burden of AF.

Impact of dabigatran on a large panel of routine or specific coagulation assays. Laboratory recommendations for monitoring of dabigatran etexilate

Due to low bioavailability and high inter-individual variability, monitoring of dabigatran may be required in specific situations to prevent the risk of bleedings or thrombosis. The aim of the study was to determine which coagulation assay(s) could be used to assess the impact of dabigatran on secondary haemostasis. Dabigatran was spiked at concentrations ranging from 4.7 ng/ml to 943.0 ng/ml in pooled citrated human platelet-poor plasma. The following clotting assays were performed: prothrombin time (PT); activated partial thromboplastin time (aPTT); thrombin time (TT); ecarin clotting time (ECT); ecarin chromogenic assay (ECA); prothrombinase-induced clotting time (PiCT); activated clotting time (ACT); Hemoclot Thrombin Inhibitor (HTI) and thrombin generation assay (TGA). A concentration-dependent prolongation of PT, dPT, and aPTT was observed with aPTT being the more sensitive test. The results varied mostly due to the clotting reagent. HTI, ECT and TGA were the most sensitive tests but are not available 24 hours a day. In addition, HTI showed a linear correlation with a good reproducibility. Dabigatran induced a concentration-dependent delay and inhibition of tissue factor-induced TGA. Cut-offs related with higher risk of bleedings or thrombosis were defined for each reagent of aPTT and HTI. In conclusion, aPTT could be used for the monitoring of dabigatran and as screening test for the risk of overdose. However, because of its higher sensitivity, good reproducibility, excellent linear correlation at all doses, its simplicity of use, and possibilities of automation, HTI should be considered as the gold-standard.

A retrospective assessment comparing pharmacist-managed anticoagulation clinic with physician management using international normalized ratio stability

To assess the rates of therapeutic international normalized ratio (INR) levels between pharmacist-managed clinics compared to traditional physician-management and to determine the variation in rates of therapeutic INR levels between pharmacist-managed clinic data compared to physician-management. Retrospective, randomized, chart review. Referral only, outpatient, pharmacist based anticoagulation clinic under a community based tertiary care health system. Sixty-four patients with at least 1 year's worth of visits to the pharmacist managed clinic were reviewed for INR stability. The average percentage of visits within the defined therapeutic range, was 71.1% for the physician-managed group versus 81.1% for the pharmacist-managed group (P < 0.0001). The estimated variance in average therapeutic INR rates was double for the physician-managed group (365.7) versus the pharmacist-managed group (185.2) (P = 0.004). The pharmacist-managed anti-coagulation clinic had higher rates of INRs determined to be therapeutic and also exhibited significantly less variability in therapeutic INR rates relative to the physician-managed service.

Thromboembolism prophylaxis with dabigatran leads to lower perioperative blood loss than with dalteparin in primary knee arthroplasty

INTRODUCTION

Low-molecular-weight heparins (LMWH) are commonly used in thrombosis prophylaxis after total knee arthroplasty. In contrast to LMWH, dabigatran etexilate is an oral and direct acting anticoagulant. The hypothesis of the present study was that blood loss occurring in total knee arthroplasty (TKA) is not greater after dabigatran etexilate than after dalteparin.

METHOD

All patients suffering from primary arthrosis of knee joint that had received a total knee arthroplasty were included in this retrospective case-control study. Two groups were formed (dalteparin versus dabigatran etexilate) and the perioperative blood loss was compared using the formula of Nadler (V = EBV × ln (Hct(0)/Hct(1)) [V = blood loss (l); EBV = blood volume (l); Hct(0) = preoperative haematocrit; Hct(1) = haematocrit on the first postoperative day].

PATIENTS

A total of 155 patients, 61 men and 94 women, were included. The calculated blood loss differed significantly between the two groups. The blood loss was on average 1.5 ± 0.58 l [0.32-2.9 l] in the dalteparin group, compared with 1.3 ± 0.63 l [0.29-4.31 l] in the dabigatran etexilate group (p < 0.01). None of the patients of both observed groups showed clinical signs of thrombosis or pulmonary artery embolism.

RESULTS

Dabigatran etexilate showed a lower perioperative blood loss than dalteparin by comparable safety of both drugs.

CONCLUSION

Whether the timing of administration or pharmacological factors were responsible for this cannot be explained by our study.

The role of apixaban for venous and arterial thromboembolic disease

OBJECTIVE

To provide a comprehensive review of the pharmacology, pharmacokinetics, pharmacodynamics, clinical trial data, adverse effects, and drug interactions of apixaban.

DATA SOURCES

An English-language literature search was performed with MEDLINE/PubMed from January 2007 to August 2011 using the search terms apixaban, factor Xa inhibitors, FXa inhibitors, BMS-562247-01, venous thromboembolism, deep vein thrombosis, pulmonary embolism, myocardial infarction, acute coronary syndrome, ACS, atrial fibrillation, atrial arrhythmias, total hip replacement or arthroplasty, total knee replacement or arthroplasty, and orthopedic surgery to identify relevant articles. The references of the retrieved articles, professional society meeting abstracts, and the Web site www.clinicaltrials.gov were reviewed to identify other pertinent articles.

STUDY SELECTION AND DATA ABSTRACTION

Pertinent original studies involving apixaban's pharmacology, pharmacokinetics, drug interactions, and clinical efficacy and safety data were included.

DATA SYNTHESIS

Results of 2 large Phase 3 trials suggest that apixaban is superior for stroke and systemic embolism prevention compared to both aspirin and warfarin in patients with atrial fibrillation (AF); rates of major bleeding and intracranial hemorrhage were similar to those of aspirin but significantly reduced compared to warfarin. Completed trials in orthopedic surgery found apixaban to be superior to enoxaparin in total hip replacement (THR) surgery but inferior in total knee replacement (TKR) surgery, with similar rates of major bleeding. A Phase 3 trial of apixaban in acute coronary syndrome was stopped early because of excess bleeding. Future Phase 3 trials will help to determine apixaban's role for treatment of deep vein thrombosis and pulmonary embolism. Currently, apixaban is approved only in Europe for prophylaxis of venous thromboembolism in adults who have undergone elective THR or TKR.

CONCLUSIONS

A Phase 3 trial in patients with AF revealed apixaban to be superior to warfarin for stroke and systemic embolism prophylaxis, with lower rates of major bleeding. Further studies will help to confirm the role of apixaban for other indications.