[Anticoagulant therapy in secondary prevention of coronary events]

Secondary prevention of atherothrombotic events is the domain of antiplatelet therapy and according to present risk is used one drug strategy or combination of acetylsalicylic acid with ADP receptor blockers. The importance of the combination of dual antiplatelet therapy together with xabans or dabigatran was investigated in 6 clinical trials. Only one of them (ATLAS ACS 2-TIMI 51) indicated that treatment with small dose of rivaroxaban (2 × 2.5 mg) may be added to dual strategy of acetylsalicylic acid and clopidogrel. The risk of major bleeding event is increased and net clinical benefit is only about 0.5 % per year. Dual therapy with aspirin and prasugrel or tikagrelor is beneficial. In the second part of the review is discussed higher incidence of myocardial infarction in controlled group in the trial comparing treatment of dabigatran with warfarin. This relationship has not been resolved, however, in patients with higher risk of coronary events and indication of anticoagulant treatment with direct oral anticoagulants it is recommended to choose from xabans (apixaban and rivaroxaban).

Estimated medical cost reductions associated with use of novel oral anticoagulants vs warfarin in a real-world non-valvular atrial fibrillation patient population

OBJECTIVE

RESULTS of randomized clinical trials (RCT) demonstrate that novel oral anticoagulants (NOAC) are effective therapies for reducing the risk of stroke in non-valvular atrial fibrillation (NVAF). Prior medical cost avoidance studies have used warfarin event rates from RCTs, which may differ from patients receiving treatment in a real-world (RW) setting, where the quality of care may not be the same as in a RCT. The purpose of this study was to estimate the change in medical costs related to stroke and major bleeding for each NOAC (apixaban, dabigatran, and rivoraxaban) relative to warfarin in a RW NVAF population.

METHODS

Patients (n = 23,525) with a diagnosis of NVAF during 2007-2010 were selected from a Medco population of US health plans. Stroke and major bleeding excluding intracranial hemorrhage (MBEIH) events were identified using diagnosis codes on medical claims. RW reference event rates were calculated during periods of warfarin exposure. RW event rates for NOACs were estimated by multiplying the corresponding relative risk (RR) from the RCTs by each reference rate. Absolute risk reductions (ARR) or number of events avoided per patient year were then estimated. Changes in medical costs associated with each NOAC were calculated by applying the ARR to the 1-year cost for each event. Costs for stroke and MBEIH were obtained from the literature. Drug and international normalized ratio monitoring costs were not considered in this analysis.

RESULTS

Compared to RW warfarin, use of apixaban and dabigatran resulted in total (stroke plus MBEIH) medical cost reductions of $1245 and $555, respectively, during a patient year. Rivaroxaban resulted in a medical cost increase of $144.

CONCLUSIONS

If relative risk reductions demonstrated in RCTs persist in a RW setting, apixaban would confer the greatest medical cost savings vs warfarin, resulting from significantly lower rates of both stroke and MBEIH.

Approach to the new oral anticoagulants in family practice: part 2: addressing frequently asked questions

OBJECTIVE

To address common "what if" questions that arise relating to the long-term clinical follow-up and management of patients receiving the new oral anticoagulants (NOACs).

SOURCES OF INFORMATION

For this narrative review, we searched the PubMed database for recent (January 2008 to week 32 of 2013) clinical studies relating to NOAC use for stroke prevention in atrial fibrillation and for the treatment of acute venous thromboembolism. We used this evidence base to address prespecified questions relating to NOAC use in primary care settings.

MAIN MESSAGE

Dabigatran and rivaroxaban should be taken with meals to decrease dyspepsia and increase absorption, respectively. There are no dietary restrictions with any of the NOACs, beyond moderating alcohol intake, and rivaroxaban and apixaban can be crushed if required. The use of acid suppressive therapies does not appear to affect the efficacy of the NOACs. As with warfarin, patients taking NOACs should avoid long-term use of nonsteroidal anti-inflammatory and antiplatelet drugs. For patients requiring surgery, generally NOACs should be stopped 2 to 5 days before the procedure, depending on bleeding risk, and the NOAC should usually be resumed at least 24 hours after surgery. Preoperative coagulation testing is generally unnecessary. In patients who develop bleeding, minor bleeding typically does not require laboratory testing or discontinuation of NOACs; with major bleeding, the focus should be on local measures to control the bleeding and supportive care, and coagulation testing should be performed. There are currently no antidotes to reverse NOACs. The NOACs should not be used in patients with valvular heart disease, prosthetic heart valves, cancer-associated deep vein thrombosis, or superficial thrombophlebitis.

CONCLUSION

Management of "what if" scenarios for patients taking NOACs have been proposed, but additional study is needed to address these issues, especially periprocedural management and bleeding.

The management of dental patients taking new generation oral anticoagulants

Recently, new oral anticoagulants have been introduced as alternatives to warfarin. While national guidelines for treatment of dental patients taking warfarin as an anticoagulant are well-established, no such information is available for these novel therapeutic agents. At present, the local guidance available is contradictory between different health boards/health planning units, and liaison with the medical practitioner managing the individual patient's anticoagulation is imperative if any invasive procedure is proposed. This paper examines the available evidence regarding these drugs and sets out proposals for clinical guidance of dental practitioners treating these patients in primary dental care.

Antithrombotic triple therapy and coagulation activation at the site of thrombus formation: a randomized trial in healthy subjects

BACKGROUND

Patients with acute coronary syndrome and concomitant atrial fibrillation may require antithrombotic triple therapy but clinical evidence of safety and efficacy is poor. We have therefore studied the combination of different antithrombotic medicines for coagulation activation in an in vivo model in the skin microvasculature.

METHODS AND RESULTS

Platelet activation (β-thromboglobulin [β-TG]) and thrombin generation (prothrombin fragment 1 + 2 [F1+2 ], thrombin-antithrombin complex [TAT]) were studied in an open-label, randomized, parallel group trial in 60 healthy male subjects (n = 20 per group) who received ticagrelor and acetylsalicylic acid (ASA) in combination with dabigatran (150 mg bid), rivaroxaban (20 mg od) or phenprocoumon (INR 2.0-3.0). Coagulation biomarkers in shed blood were assessed at 3 h after monotherapy with the medicines under study, at 3 h after triple therapy dosing and at steady state trough conditions. Single doses of ticagrelor, dabigatran or rivaroxaban caused comparable decreases in shed blood β-TG and were more pronounced than phenprocoumon at an INR of 2.0-3.0. In contrast, thrombin generation was more affected by rivaroxaban and phenprocoumon than by dabigatran. During triple therapy a similarly sustained inhibition of platelet activation and thrombin generation with a maximum decrease of β-TG, F1+2 and TAT at 3 h post-dosing was noted, which remained below pre-dose levels at trough steady state.

CONCLUSION

A triple therapy at steady state with ticagrelor plus ASA in combination with dabigatran or rivaroxaban is as effective as a combination with phenprocoumon for platelet activation and thrombin generation in vivo.

A systematic review and adjusted indirect comparison of oral anticoagulants

EDUCATIONAL OBJECTIVES As a result of reading this article, physicians should be able to: 1. Recognize the high risk of postoperative venous thromboembolism (VTE) in patients undergoing major orthopedic surgery. 2. Distinguish the different pharmacological mechanisms of VTE prophylaxis drugs. 3. Delineate the advantages and disadvantages of each VTE prophylaxis drug. 4. Recognize that rivaroxaban is as efficacious as apixaban but can increase the risk of hemorrhage. Patients undergoing major orthopedic surgery are at high risk for developing postoperative venous thromboembolism (VTE). The authors analyzed the available evidence on the efficacy and safety of dabigatran, apixaban, and rivaroxaban vs low-molecular-weight heparins (LMWHs) as VTE prophylaxis in major orthopedic surgery. Outcomes evaluated included total VTE, deep venous thrombosis (DVT), pulmonary embolism (PE), death, and major bleeding. Rivaroxaban and apixaban are more efficacious than dabigatran and are as safe as dabigatran. Rivaroxaban is as efficacious as apixaban but can increase the risk of hemorrhage.

Approach to the new oral anticoagulants in family practice: part 1: comparing the options

OBJECTIVE

To compare key features of the new oral anticoagulants (NOACs)-dabigatran, rivaroxaban, and apixaban-and to address questions that arise when comparing the NOACs.

SOURCES OF INFORMATION

PubMed was searched for recent (January 2008 to week 32 of 2013) clinical studies relating to NOAC use for stroke prevention in atrial fibrillation (AF) and for the treatment of acute venous thromboembolism (VTE).

MAIN MESSAGE

All NOACs are at least as effective as warfarin for stroke prevention in patients with nonvalvular AF, and are at least as safe in terms of bleeding risk according to 3 large trials. Meta-analyses of these trials have shown that, compared with warfarin therapy, NOACs reduced total mortality, cardiovascular mortality, and intracranial bleeding, and there was a trend toward less overall bleeding. Practical advantages of NOACs over warfarin include fixed once- or twice-daily oral dosing without the need for coagulation monitoring, and few known or defined drug or food interactions. Potential drawbacks of NOACs include a risk of bleeding that might be increased in patients older than 75 years, increased major gastrointestinal bleeding with high-dose dabigatran, increased dyspepsia with dabigatran, the lack of a routine laboratory test to reliably measure anticoagulant effect, and the lack of an antidote for reversal. No direct comparisons of NOACs have been made in randomized controlled trials, and the choice of NOAC is influenced by individual patient characteristics, including risk of stroke or VTE, risk of bleeding, and comorbidity (eg, renal dysfunction).

CONCLUSION

The NOACs represent important alternatives in the management of patients with AF and VTE, especially for patients who have difficulty accessing regular coagulation monitoring. The companion to this article addresses common "what if" questions that arise in the long-term clinical follow-up and management of patients receiving NOACs.

The potential of target-specific oral anticoagulants for the acute and long-term treatment of venous thromboembolism

BACKGROUND

Venous thromboembolism (VTE) comprises both deep vein thrombosis and pulmonary embolism. VTE is a leading cause of morbidity and mortality worldwide and its increasing incidence and prevalence are a major health concern. The primary medical objective during the acute phase of VTE treatment is to prevent thrombus extension and embolization. Extended treatment aims to prevent or minimize long-term complications, such as recurrent VTE, post-thrombotic syndrome and chronic thromboembolic pulmonary hypertension.

SCOPE

Anticoagulant therapy has been the mainstay of treatment for VTE and traditionally involves initial therapy with heparin, overlapping with and followed by a vitamin K antagonist. Although effective, standard heparin/vitamin K antagonist therapy has several limitations that can be overcome by more recently developed target-specific oral anticoagulants (TSOACs). These agents have predictable pharmacokinetics, a rapid onset of action and few drug-drug or drug-food interactions. Furthermore, TSOACs offer convenient anticoagulation without the need for routine coagulation monitoring and dose adjustment.

FINDINGS

The efficacy and safety data from phase III clinical trials support the use of TSOACs for VTE treatment, including in special patient populations. Risk-stratification tools and strategies have been developed to assist physicians in managing anticoagulation treatment.

CONCLUSIONS

Rivaroxaban is the first TSOAC to gain widespread approval for the treatment of acute deep vein thrombosis and pulmonary embolism and the long-term prevention of recurrent VTE as monotherapy. Dabigatran has also been approved for this indication recently. TSOACs, especially as monotherapy, represent a paradigm shift in clinical practice for the management of patients with VTE.

Left atrial appendage thrombus with resulting stroke post-RF ablation for atrial fibrillation in a patient on dabigatran

Dabigatran etexilate is licensed for use in prevention of deep venous thromboembolism and in prevention of stroke and systemic embolism in nonvalvular atrial fibrillation (AF). It has also been used in patients for other indications as a substitute for warfarin therapy because it requires no monitoring; one group being patients undergoing radiofrequency (RF), ablation for AF, although there have been no consensus guidelines with regards to dosage and timing of dose. We report the case of a patient with documentary evidence of left atrial appendage (LAA) thrombus formation and neurological sequelae post-RF ablation despite being on dabigatran. This case highlights the concern that periprocedural dabigatran may not provide adequate protection from development of LAA thrombus and that a standardised protocol will need to be developed and undergo large multicentre trials before dabigatran can be safely used for patients undergoing RF-ablation.

Evaluation of medical costs associated with use of new oral anticoagulants compared with standard therapy among venous thromboembolism patients

OBJECTIVE

This study evaluated differences in medical costs associated with clinical end-points from randomized clinical trials that compared the new oral anticoagulants (NOACs), dabigatran, rivaroxaban, apixaban, and edoxaban, to standard therapy for treatment of patients with venous thromboembolism (VTE).

RESEARCH DESIGN AND METHODS

Event rates of efficacy and safety end-points from the clinical trials (RE-COVER, RE-COVER II, EINSTEIN-Pooled, AMPLIFY, Hokusai-VTE trial) were obtained from published literature. Incremental annual medical costs among patients with clinical events from a US payer perspective were obtained from the literature or healthcare claims databases and inflation adjusted to 2013 costs. Differences in total medical costs associated with clinical end-points for the NOACs vs standard therapy were then estimated. One-way and Monte Carlo sensitivity analyses were carried out.

RESULTS

A lower rate of major bleedings was associated with use of any of the NOACs vs standard therapy. Except for dabigatran, use of NOACs was also associated with a lower rate of recurrent VTE/death. As a result of the reduction in clinical event rates, the overall medical cost differences were -$146, -$482, -$918, and -$344 for VTE patients treated with dabigatran, rivaroxaban, apixaban, and edoxaban, respectively, vs patients treated with standard therapy.

CONCLUSIONS

When any of the four NOACs are used instead of standard therapy for acute VTE, treatment medical costs are reduced. Apixaban is associated with the greatest reduction in medical costs, which is driven by medical cost reductions associated with both efficacy and safety end-points. Further evaluation may be needed to validate these results in the real-world setting.

[Extended options of anticoagulant treatment in thromboembolism]

Thromboembolic disease (TD) is a relatively common disease with acute risk of death and potential long-term consequences in term of postthrombotic syndrome or chronic pulmonary hypertension. Anticoagulant therapy is the basic therapeutic procedure; thrombolytic therapy and the introduction cava filter are appropriately indicated for individual cases. In past few years, new direct oral anticoagulant drugs (NOAC) have occurred - Xa factor or thrombin inhibitors which have demonstrated the same efficacy and even higher safety in comparison to conventional treatment. In mid 2014, 3 drugs of this group are registered in Czech Republic - rivaroxaban (Xarelto®), dabigatran (Pradaxa®) and apixaban (Eliquis®). These drugs have comparable efficacy and safety but they differ in schedule of dose administration. Rivaroxaban and apixaban can be administered immediately after diagnosis of venous thrombosis or hemodynamically stable pulmonary embolism. LMWH application has to precede few days the administration of dabigatran. Limitation of new drugs is their price. Unavailability of antidotes is temporary because current researches continue to find one for dabigatran and another for both of xabans. Duration of anticoagulant treatment after acute phase depends on the presence of thrombosis risk factors and the individual bleeding risk. Minimal duration of anticoagulant therapy is 3 months, commonly 6-12 months and in high risk patients it is "long term" treatment. Good results of new anticoagulant drugs in trials in term of thromboembolism recurrence prevention may change established habits in TD patients with long term treatment.

[Comparison of the safety of rivaroxaban versus dabigatran therapy in patients with persistent atrial fibrillation]

For 60 years, vitamin K antagonists have been used in prevention of thromboembolic complications in the course of atrial fibrillation (AF), however such therapy is associated with many inconveniences. New oral anticoagulants (NOAC), rivaroxaban and dabigatran, represent an attractive alternative to VKA.

THE AIM OF THE STUDY

Yo evaluate the safety of a 6-month therapy with rivaroxaban and dabigatran in patients (pts) with persistent AF.

MATERIALS AND METHODS

The analysis included 24 pts (14 females, 10 males) with nonvalvular AF and indications for oral anticoagulant therapy (CHA2DS2-VASc > or = 2, HAS-BLED < 3), hospitalized in the Clinic of Internal Diseases and Clinical Pharmacology of the Medical University of Lodz between July 2012 and September 2013. In the group of patients treated chronically with VKA, laboratory tests (GFR, creatinine, ALT AST, coagulation) were performed during their stay in the clinic. The patients were randomly assigned to the treatment with one of the new NOACs, rivaroxaban or dabigatran. After a 6-month period, the patients completed a questionnaire on their general health condition and follow-up laboratory tests were performed.

RESULTS

In the group of pts. receiving dabigatran INR increased by 23% (p = 0.0002) and APTT prolongation by 91% was noted (p = 0.0004) whereas in the group of pts receiving rivaroxaban an INR increase by 17% (p = 0.04) and APTT prolongation by 32% (p = 0.0043) were observed. After a 6-month therapy, dabigatran prolongs APTT significantly more, as compared to rivaroxaban (p=0.0002). Among patients using dabigatran, 16.7% experienced the following symptoms: abdominal pain, gastritis, nausea. 8.3% patients experienced bleeding from haemorrhoids, easier bruising. In the group of patients receiving rivaroxaban, 16.7% experienced the following symptoms: nosebleeds and easier bruising; 8.3%: bleeding from gums, haematuria. 25%: pruritus, rash: 8.3%. The hazard ratio (HR) for occurrence of dyspeptic symptoms was 1.13 for dabigatran. Minor bleeding is 3.6 times more common when using rivaroxaban.

CONCLUSIONS

Significant increase of INR and prolongation of APTT are observed after a 6-month therapy with rivaroxaban or dabigatran. Additionally, dabigatran significantly prolongs the prothrombin time. Despite the fact that dabigatran caused larger prolongation of APTT minor bleeding episodes occurred more frequently in patients treated with rivaroxaban. No worsening of kidney or liver function was observed during the 6-month therapy with rivaroxaban or dabigatran. Rywaroxaban more frequently causes minor bleeding, whereas treatment with dabigatran is associated with more frequent gastrointestinal adverse symptoms.

Anticoagulant treatment in German family practices - screening results from a cluster randomized controlled trial

BACKGROUND

Oral anticoagulation (OAC) with coumarins and new anticoagulants are highly effective in preventing thromboembolic complications. However, some studies indicate that over- and under-treatment with anticoagulants are fairly common. The aim of this paper is to assess the appropriateness of treatment in patients with a long-term indication for OAC, and to describe the corresponding characteristics of such patients on the basis of screening results from the cluster randomized PICANT trial.

METHODS

Randomly selected family practices in the federal state of Hesse, Germany, were visited by study team members. Eligible patients were screened using an anonymous patient list that was generated by the general practitioners' software according to predefined instructions. A documentation sheet was filled in for all screened patients. Eligible patients were classified into 3 categories (1: patients with a long-term indication for OAC and taking anticoagulants, 2: patients with a long-term indication for OAC but not taking anticoagulants, 3: patients without a long-term indication for OAC but taking an anticoagulant on a permanent basis). IBM SPSS Statistics 20 was used for descriptive statistical analysis.

RESULTS

We screened 2,036 randomly selected, potentially eligible patients from 52 family practices. 275 patients could not be assigned to one of the 3 categories and were therefore not considered for analysis. The final study sample comprised 1,761 screened patients, 1,641 of whom belonged to category 1, 78 to category 2, and 42 to category 3. INR values were available for 1,504 patients of whom 1,013 presented INR values within their therapeutic ranges. The majority of screened patients had very good compliance, as assessed by the general practitioner. New antithrombotic drugs were prescribed in 6.1% of cases.

CONCLUSIONS

The screening results showed that a high proportion of patients were receiving appropriate anticoagulation therapy. The numbers of patients with a long-term indication for OAC therapy that were not receiving oral anticoagulants, and without a long-term indication that were receiving OAC, were considerably lower than expected. Most patients take coumarins, and the quality of OAC control is reasonably high.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN41847489.

Non-vitamin K antagonist oral anticoagulants in atrial fibrillation and venous thromboembolism: where are we now?

Four non-vitamin-K antagonist oral anticoagulants (NOACs) are now available and are variously approved for stroke prevention in atrial fibrillation and the management of venous thromboembolism. On the whole, these drugs offer clear benefits over warfarin, overcoming problems with unpredictable individual responses and avoiding the need for frequent and resource-intensive monitoring. Sufficient data are now available to recommend the use of particular NOACs in defined settings. As a group these drugs offer a real alternative to warfarin; their more widespread use for stroke prevention in atrial fibrillation, in the management of venous thromboembolism, and perhaps in other settings promises to bring real clinical gains for at-risk populations worldwide. This review highlights the growing importance of effective anticoagulation therapy at a time when cardiovascular risk profiles are evolving, discusses the relative merits of the NOACs over warfarin, and describes the use of specific agents in specific patient populations.

Determination of dabigatran, rivaroxaban and apixaban by ultra-performance liquid chromatography - tandem mass spectrometry (UPLC-MS/MS) and coagulation assays for therapy monitoring of novel direct oral anticoagulants

BACKGROUND

Three novel direct oral anticoagulants (DOACs) have recently been registered by the Food and Drug Administration and European Medicines Agency Commission: dabigatran, rivaroxaban, and apixaban. To quantify DOACs in plasma, various dedicated coagulation assays have been developed.

OBJECTIVE

To develop and validate a reference ultra-performance liquid chromatography - tandem mass spectrometry (UPLC-MS/MS) method and to evaluate the analytical performance of several coagulation assays for quantification of dabigatran, rivaroxaban, and apixaban.

METHODS

The developed UPLC-MS/MS method was validated by determination of precision, accuracy, specificity, matrix effects, lower limits of detection, carry-over, recovery, stability, and robustness. The following coagulation assays were evaluated for accuracy and precision: laboratory-developed (LD) diluted thrombin time (dTT), Hemoclot dTT, Pefakit PiCT, ECA, Liquid anti-Xa, Biophen Heparin (LRT), and Biophen DiXal anti-Xa. Agreement between the various coagulation assays and UPLC-MS/MS was determined with random samples from patients using dabigatran or rivaroxaban.

RESULTS

The UPLC-MS/MS method was shown to be accurate, precise, sensitive, stable, and robust. The dabigatran coagulation assay showing the best precision, accuracy and agreement with the UPLC-MS/MS method was the LD dTT test. For rivaroxaban, the anti-factor Xa assays were superior to the PiCT-Xa assay with regard to precision, accuracy, and agreement with the reference method. For apixaban, the Liquid anti-Xa assay was superior to the PiCT-Xa assay.

CONCLUSIONS

Statistically significant differences were observed between the various coagulation assays as compared with the UPLC-MS/MS reference method. It is currently unknown whether these differences are clinically relevant. When DOACs are quantified with coagulation assays, comparison with a reference method as part of proficiency testing is therefore pivotal.

A retrospective descriptive analysis of patient adherence to dabigatran at a large academic medical center

BACKGROUND

Clinical trials evaluating the efficacy of dabigatran followed a very strict protocol, which included close monitoring and follow-up. Patients followed in this controlled environment had an average medication possession ratio (MPR) greater than 0.95. However, very few studies have evaluated patient adherence to dabigatran in a real-world setting. Other studies of chronic medications indicate patients are not reliably adherent to twice daily regimens. Adherence to therapy is particularly important for direct thrombin inhibitors because there may be a risk of increased thromboembolic events associated with poor adherence to these agents. 

OBJECTIVE

To identify the MPR for patients prescribed dabigatran at a large academic medical center and affiliated clinics. 

METHODS

This retrospective descriptive study evaluated the MPR for patients prescribed dabigatran between January 1, 2012, and December 31, 2012. Patients included in this study had to receive dabigatran for a minimum of 3 months, have a primary care physician or cardiologist at the medical center or affiliated clinics, and must not use a mail order pharmacy. Patient MPR was calculated based on prescriptions picked up from the patient.

RESULTS

After screening 400 patients, 159 patients met eligibility criteria. The mean MPR for the patients in this study was 0.63. Overall, 43% of the patients had an MPR of less than  0.80, and the mean MPR for this subgroup was 0.39 ± 0.27; 57% of the study population had an MPR of 0.80 or higher, with a mean MPR of 0.94 ± 0.08. There was a significantly higher proportion of men (67.7%, P = 0.0112) and a larger number of "as needed medications" prescribed (1.73 vs. 0.86, P = 0.0039) in patients with an MPR  less than  0.80. There were 5 patients hospitalized during the study period (3 for bleeding, 1 for confusion, and 1 death not related to dabigatran therapy). 

CONCLUSIONS

The relatively low mean MPR seen in this study may indicate that there is a need for improved anticoagulation services and follow-up for patients taking dabigatran.

Efficacy and cost-effectiveness of dabigatran etexilate versus warfarin in atrial fibrillation in different age subgroups

This study aims to estimate the cost-effectiveness of dabigatran 150 mg twice daily versus warfarin for stroke and systemic embolism risk reduction in patients with nonvalvular atrial fibrillation initiating treatment before age 75 (<75), at or after age 75 (≥ 75), and the overall population (All) from a US Medicare payer perspective. Clinical event rates by age cohort with dabigatran or warfarin for safety-on-treatment and intent-to-treat populations were estimated from Randomized Evaluation of Long-Term Anticoagulation Therapy (RE-LY). An economic model was adapted using these data to evaluate the impact of starting age on clinical and economic outcomes. Costs were obtained from Medicare payment schedules and utilities from publications. Model outputs included event rates, costs, quality-adjusted life-years, and incremental cost-effectiveness ratios. The RE-LY analysis shows that the <75 cohort has lower rates of all events than the ≥ 75 cohort; versus warfarin, dabigatran performed better in main efficacy and safety in all age cohorts with the exception of extracranial hemorrhage in the ≥ 75 cohort. The clinical event costs avoided per patient for dabigatran were $1,100, $135, and $713 for cohorts <75, ≥ 75, and All, respectively. Extrapolating over a lifetime horizon, the model found that dabigatran resulted in lower rates of stroke and intracranial hemorrhage and higher rates for extracranial hemorrhage versus warfarin for all age cohorts. Lifetime quality-adjusted life-years and costs were higher for dabigatran than warfarin, resulting in incremental cost-effectiveness ratios of $52,773, $65,946, and $56,131 for cohorts <75, ≥ 75, and All, respectively. In conclusion, dabigatran was cost-effective versus warfarin in US patients with atrial fibrillation regardless of age of treatment initiation.

[Hemorrhagic stroke and new oral anticoagulants]

The recent release of new oral anticoagulants (NOAC) raises the question of the management of intracranial hemorrhage occurring during treatment with these molecules. Dabigatran, rivaroxaban and apixaban have different pharmacological characteristics that physicians need to know to adjust their prescription to each patient. Studies of efficacy and safety prior to the marketing of these molecules showed a decreased risk of intracranial hemorrhage compared with vitamin K antagonists. However, no reliable data are available regarding the prognosis of these hemorrhages occurring during NOAC treatment. In addition, there is no specific antidote and reversal protocol validated in humans. So, physicians are in a difficult situation when critical bleeding occurs. The timing of recovering normal hemostatic capacity is then a determinant factor of prognosis. Studies in animals or healthy volunteers showed a correction of the biological parameters using prothrombin complex concentrates activated or not, without reducing the volume of hematoma. On this basis, proposals have been issued by the french group of interest for perioperative hemostasis (GIHP) for the management of bleeding under NOAC treatment, which include management of intracranial hemorrhage.