[Proper use of oral anticoagulants in the elderly patient]. / Le bon usage des anticoagulants oraux chez le patient âgé.

Direct oral anticoagulants (DOACs) are tending to supplant antivitamin K inhibitors (VKAs) in their common indications, dominated in elderly patients by atrial fibrillation and venous thromboembolism. Nevertheless, it remains necessary to know how best to use VKAs for which there are still indications. It is also important not to assume that AODs can be prescribed without risk, while ignoring certain particularities in their handling, particularly in the most fragile patients with co-morbidities and multiple medications.

Gender differences in antithrombotic treatment in patients with atrial fibrillation from Spain versus the rest of Western Europe. GLORIA-AF Program

Background and objective:Thromboembolic risk is higher in women than men with non-valvular atrial fibrillation (NVAF). Published data indicate variability in antithrombotic use by gender and region. We analyzed gender-specific antithrombotic treatment patterns in Spain and rest of Western Europe (rWE) in patients with NVAF.Methods:GLORIA-AF (Phase III) is a global, prospective, observational study which enrolled newly diagnosed NVAF patients with CHA2DS2-VAScs≥1 (2014–2016). Analyses were performed comparing antithrombotic treatments by gender in Spain and rWE.Results:This analysis included 1163 and 7972 patients from Spain and rWE, respectively. Stroke risk was higher in women than men in both Spain and rWE. While in rWE, bleeding risk and antithrombotic treatment pattern were similar between genders, in Spain bleeding risk in women was lower and more females compared to men received OACs (95.0% versus 92.4%, d=−0.1078, respectively). Fewer Spanish patients received direct oral anticoagulants (DOACs) (women 32.1%, men 25.3%) than vitamin-K-antagonists (VKAs) (women 63.0%, men 67.1%) vs. rWE patients. In Spain women received more DOACs compared to men (56.0% versus 44.0%).Conclusions:OAC rates were higher in Spain as compared to rWE. More women received OACs in Spain, while in rWE no difference by gender was observed. DOACs in rWE are the most prescribed OAC while in Spain, due to prescription barriers, its use remains low for both genders and VKAs are preferred. Spanish women received more DOACs compared to men. (NCT01468701). (AU)

Antecedentes y objetivo:El riesgo tromboembólico es mayor en mujeres que en varones con fibrilación auricular no valvular (FANV). Existen diferencias en el uso de anticoagulantes (ACO) según sexo y zona geográfica. Se estudiaron los patrones de anticoagulación por sexo en España y el resto de Europa Occidental (rEO) en pacientes con FANV.Métodos:GLORIA-AF es un estudio observacional prospectivo (fase III) que incluyó a pacientes con diagnóstico reciente de FANV y CHA2DS2-VASc>1 (2014-2016). Se analizó la prescripción de anticoagulantes por sexo en España y el rEO.Resultados:Se incluyó a 1.163 pacientes de España y 7.972 del rEO. El riesgo de ictus fue superior en mujeres tanto en España como en el rEO. El riesgo de hemorragia y el tratamiento antitrombótico fueron similares en ambos sexos en el rEO; en España, el riesgo de hemorragia fue menor en mujeres y estas recibieron más ACO que los varones (95,0% vs. 92,4%, d=–0,1078). En España, menos pacientes recibieron ACO directos (ACOD) (mujeres 32,1%, varones 25,3%) vs. antagonistas de la vitamina K (AVK) (mujeres 63,0%, varones 67,1%), y las mujeres recibieron más ACOD que los varones (56,0% vs. 44,0%).Conclusiones:En España se emplearon más ACO que en el rEO y más mujeres fueron tratadas con ACO, mientras que en el rEO no hubo diferencias por sexo. En el rEO, los ACOD se emplearon más. En España, los ACOD se emplean menos por restricciones de prescripción y se emplean más los AVK. Las mujeres españolas reciben más ACOD que los varones. (NCT01468701). (AU)

Decision of Anticoagulation in Nonvalvular Atrial Fibrillation in the Real World in the Non-Antivitamin K Anticoagulants Era.

Background. Patients with nonvalvular atrial fibrillation (NVAF) have five times higher risk of stroke than the general population. Anticoagulation (ACO) in NVAF is a class I indication after assessing the CHA2DS2-VASc and HAS-BLED scores. However, in the real world, NVAF patients receive less ACO than needed due to patients' comorbidities that can be assessed by the Charlson comorbidity index (CCI). The use of non-antivitamin K anticoagulants (NOAC) has improved the decision to anticoagulate. Objective. We analyzed the factors influencing the ACO prescribing decision in NVAF patients in the real world and the changes induced by the introduction of NOAC. Method. We carried out an observational retrospective cross-sectional study that included consecutive patients with permanent NVAF and CHA2DS2-VASc ≥ 2, admitted to a community hospital between 2010-2011 (group 1, 286 patients), when only vitamin K antagonists (VKA) were used, and 2018-2019 (group 2, 433 patients), respectively. We calculated CHA2DS2-VASc, HAS-BLED, and CCI and recorded the ACO decision and the use of VKA or NOAC in group 2. We compared the calculated scores between ACO and non-anticoagulated (nonACO) patients in both groups and between groups. Results. A 31.5% share of patients in group 1 and 12.9% in group 2 did not receive ACO despite a CHA2DS2-VASc score ≥ 2. In group 1, nonACO patients had higher HAS-BLED and CCI scores than the ACO patients, but their CHA2DS2-VASc scores were not significantly different. Old age, dementia, severe chronic kidney disease, neoplasia, and anemia were the most frequent reasons not to prescribe anticoagulants. In group 2, more nonACO patients had dementia, diabetes mellitus, and higher HAS-BLED than ACO patients. Moderate-severe CKD, neoplasia with metastasis, liver disease, anemia, and diabetes mellitus were statistically significantly more frequent in nonACO patients from group 1 than those from group 2. In group 2, 55.7% of ACO patients received NOAC. Conclusions. In real-world clinical practice, the decision for anticoagulation in NVAF is influenced by patient age, comorbidities, and risk of bleeding, and many patients do not receive anticoagulants despite a high CHA2DS2-VASc score. The use of NOAC in the past few years has improved treatment decisions. At the same time, the correct diagnosis, treatment, and surveillance of comorbidities have cut down the risk of bleeding and allowed anticoagulant use according to guidelines.

Gender differences in antithrombotic treatment in patients with atrial fibrillation from Spain versus the rest of Western Europe. GLORIA-AF Program.

BACKGROUND AND OBJECTIVE: Thromboembolic risk is higher in women than men with non-valvular atrial fibrillation (NVAF). Published data indicate variability in antithrombotic use by gender and region. We analyzed gender-specific antithrombotic treatment patterns in Spain and rest of Western Europe (rWE) in patients with NVAF. METHODS: GLORIA-AF (Phase III) is a global, prospective, observational study which enrolled newly diagnosed NVAF patients with CHA2DS2-VAScs≥1 (2014-2016). Analyses were performed comparing antithrombotic treatments by gender in Spain and rWE. RESULTS: This analysis included 1163 and 7972 patients from Spain and rWE, respectively. Stroke risk was higher in women than men in both Spain and rWE. While in rWE, bleeding risk and antithrombotic treatment pattern were similar between genders, in Spain bleeding risk in women was lower and more females compared to men received OACs (95.0% versus 92.4%, d=-0.1078, respectively). Fewer Spanish patients received direct oral anticoagulants (DOACs) (women 32.1%, men 25.3%) than vitamin-K-antagonists (VKAs) (women 63.0%, men 67.1%) vs. rWE patients. In Spain women received more DOACs compared to men (56.0% versus 44.0%). CONCLUSIONS: OAC rates were higher in Spain as compared to rWE. More women received OACs in Spain, while in rWE no difference by gender was observed. DOACs in rWE are the most prescribed OAC while in Spain, due to prescription barriers, its use remains low for both genders and VKAs are preferred. Spanish women received more DOACs compared to men. (NCT01468701).

Is antivitamin K reversal required in patients with cirrhosis undergoing liver transplantation?

BACKGROUND: Antivitamin K agent (AVK) reversal in patients with cirrhosis awaiting liver transplantation (LT) is not defined in guidelines. We investigated the effect of reversion with prothrombin complex concentrate (PCC) on intraoperative transfusion, bleeding, and safety in LT patients on AVK. STUDY DESIGN AND METHODS: In 511 patients undergoing LT, we identified 25 patients treated with AVK (AVK group) and 13 patients with incidental portal vein thrombosis (PVT) without AVK (incidental PVT group). Fifty patients who underwent LT without PVT or AVK matched by age, model for end stage of liver disease (MELD), body mass index (BMI), and cirrhosis etiology were selected as the control group. RESULTS: There were no significant differences between the three groups in intraoperative blood loss, transfusion, and postoperative bleeding. In the AVK group, there were no differences between patients who received PCC and those who did not in intraoperative blood loss, red blood cells, fibrinogen, and platelet transfusion, or postoperative bleeding. PCC use had no effect on RBC transfusion in patients who had international normalized ratio or clotting time above versus below median values of the two parameters at baseline (2.3 and 103 s, respectively). No thrombotic events were detected in patients who received PCC. DISCUSSION: These data suggest that systematic administration of PCC to revert AVK prior to LT should be reconsidered.

Prevalence and management of antivitamin K overdose in a hospital setting.

INTRODUCTION: Vitamin K antagonist (VKA) related adverse events are the first cause for iatrogenic events in France, particularly due to the narrow therapeutic margin. The risk of bleeding increases significantly when the INR level is ≥5. The main objective of this study was to assess the prevalence of VKA overdose in a hospital setting (at D2 of hospital entry) and to evaluate physicians' adherence to clinical practice guidelines for the management of VKA overdose according to French National Authority for Health recommendations. METHODS: This single-center retrospective observational study consisted in querying the computerized database of a Parisian hospital on 21275INR determinations (3995 patients, 6813 hospital stays) performed between 2013 and 2018. RESULTS: An INR level ≥5 was noted during 350 (6%) of the hospital stays, in 331 patients (of whom 57% were women). The mean age of the patient population with an INR≥5 was 81.1 years. Infection, heart failure and renal failure were the most frequent acute medical conditions for hospital admission. Twenty-three patients (7%) had a bleeding complication, 11 of which were major bleeding complications. Older age was associated with the severity of bleeding complications. Fifteen in-hospital deaths (4%) were reported, not related to bleeding events. The management of VKA overdose did not comply with the recommendations in 43% of cases, in particular for the highest INRs (50% of noncompliance for an INR>6.4). Non-compliance with recommendations for VKA overdose was related to: the delay until the INR was checked (44% of cases); the indication for prescribing vitamin K (34% of cases); the dose or route of administration of vitamin K therapy (19% of cases); and the interruption or not of VKA therapy (12% of cases). CONCLUSION: The management of VKA overdose in a hospital setting remains non-compliant with the recommendations in almost half of the cases, mainly due to the delayed INR control and inappropriate management of vitamin K therapy. Computerized alert system would be helpful for personalized patient management and improved pharmacovigilance to prevent iatrogenic VKA events.

Differences in teratogenicity of some vitamin K antagonist substances used as human therapeutic or rodenticide are due to major differences in their fate after an oral administration.

All vitamin K antagonist active substances used as rodenticides were reclassified in 2016 by the European authorities as active substances "toxic for reproduction", using a "read-across" alternative method based on warfarin, a human vitamin K antagonist drug. Recent study suggested that all vitamin K antagonist active substances are not all teratogenic. Using a neonatal exposure protocol, warfarin evokes skeletal deformities in rats, while bromadiolone, a widely used second-generation anticoagulant rodenticide, failed to cause such effects. Herein, using a rat model we investigated the mechanisms that may explain teratogenicity differences between warfarin and bromadiolone, despite their similar vitamin K antagonist mechanism of action. This study also included coumatetralyl, a first-generation active substance rodenticide. Pharmacokinetic studies were conducted in rats to evaluate a potential difference in the transfer of vitamin K antagonists from mother to fetus. The data clearly demonstrate that warfarin is highly transferred from the mother to the fetus during gestation or lactation. In contrast, bromadiolone transfer from dam to the fetus is modest (5% compared to warfarin). This difference appears to be associated to almost complete uptake of bromadiolone by mother's liver, resulting in very low exposure in plasma and eventually in other peripheric tissues. This study suggests that the pharmacokinetic properties of vitamin K antagonists are not identical and could challenge the classification of such active substances as "toxic for reproduction".

Biomarkers Potency to Monitor Non-target Fauna Poisoning by Anticoagulant Rodenticides.

The widespread use of pesticides to control agricultural pests is a hot topic on the public scene of environmental health. Selective pest control for minimum environmental impact is a major goal of the environmental toxicology field, notably to avoid unintended poisoning in different organisms. Anticoagulant rodenticides cause abnormal blood coagulation process; they have been widely used to control rodents, allowing inadvertent primary and secondary exposure in domestic animals and non-target predatory wildlife species through direct ingestion of rodenticide-containing bait or by consumption of poisoned prey. To report toxic effect, the most common approach is the measurement of liver or plasma residues of anticoagulant rodenticides in dead or intoxicated animals showing clinical symptoms. However, one major challenge is that literature currently lacks a hepatic or plasma concentration threshold value for the differentiation of exposure from toxicity. Regarding the variation in pharmacology properties of anticoagulant rodenticides inter- and intra-species, the dose-response relationship must be defined for each species to prejudge the relative risk of poisoning. Beyond that, biomarkers are a key solution widely used for ecological risk assessment of contaminants. Since anticoagulant rodenticides (AR) have toxic effects at the biochemical level, biomarkers can serve as indicators of toxic exposure. In this sense, toxicological knowledge of anticoagulant rodenticides within organisms is an important tool for defining sensitive, specific, and suitable biomarkers. In this review, we provide an overview of the toxicodynamic and toxicokinetic parameters of anticoagulant rodenticides in different animal species. We examine different types of biomarkers used to characterize and differentiate the exposure and toxic effects of anticoagulant rodenticide, showing the strengths and weaknesses of the assays. Finally, we describe possible new biomarkers and highlight their capabilities.

[Quality and determinants of anticoagulation therapy by AVK in elderly subjects: study of a continuous series of 155 patients hospitalized in geriatric medicine]. / Qualité et déterminants de l'équilibre de l'anticoagulation par AVK des sujets âgés : étude d'une série continue de 155 patients hospitalisés en gériatrie aiguë.

AVK could be prescribed in elderly patients over 75 years for the prevention of thromboembolic complications of atrial fibrillation (AF). The objective of this study was to study the quality of the anticoagulation balance by AVK and its determinants. Inclusion of all patients ≥ 75 years of age treated with AVK for an AF hospitalized in the acute geriatric department of the University hospital of Dijon. The balance of the AVK treatment was determined by the input INR and the calculation of the TTR. The last four INRs prior to admission were retrospectively collected for its calculation. Each patient had a standardized geriatric evaluation (EGS): lifestyle, MMSE, nutritional status (albumin), polypathology (Charlson), level of dependence (ADL-IADL). Bleeding complication were collected. 155 patients aged over 75 years (87±5.6 years, 88 women and 67 men) were included. The mean TTR was 55.4±31.2%. Only 46% of patients had a correct TTR (≥ 75%). The balance was significantly worse in women than in men (49.3±29.5 vs 60.1±31.8%; p=0.0326), and in case of haematological pathology (41.7±27.1 vs 57.2± 9.8; p=0.047) but better with high BMI (r=0.416, p=0.001). No EGS parameters were associated with the quality of anticoagulation. The control of AVK therapy is insufficient in geriatric elderly subjects. No modifiable explicative geriatric factor has been identified. If AVK remains a therapeutic option, direct oral anticoaulants should be considered as the first choice.

[Direct oral anticoagulants (DOACS): A necessary focus]. / Anticoagulants oraux directs (AOD) : une mise au point nécessaire.

In 2008, we decided to enter the era of direct oral anticoagulants (DOACS). Was that the right decision to make? The answer will depend on how well we meet the conditions of proper use. This means avoiding underdosing and overdosing as well as understanding how DOACS were validated so that our prescriptions fulfill their role in the management of thrombotic disease.

Study of the efficiency of anticoagulant rodenticides to control Mus musculus domesticus introgressed with Mus spretus Vkorc1.

BACKGROUND: Antivitamin K anticoagulant (AVK) rodenticides are commonly used to control rodent pests worldwide. They specifically inhibit the VKORC1 enzyme essential for the recycling of vitamin K, and thus prevent blood clotting and cause death by haemorrhage. Numerous mutations or polymorphisms of the Vkorc1 gene were reported in rodents, and some led to resistance to rodenticides. In house mice (Mus musculus domesticus), adaptive introgression of the Vkorc1 gene from the Algerian mouse (Mus spretus) was reported. This adaptive introgression causes the substitution of four amino acids in M. musculus domesticus. RESULTS: The consequences of introgression were assessed by (i) the characterisation of the in vivo resistant phenotype of adaptive Vkorc1spr -introgressed mice, (ii) the characterisation of the ex vivo resistance phenotype of the liver VKOR activity and (iii) the comparison of these results with the properties of recombinant VKORC1spr protein expressed in yeast. The resistance factor (from 1 to 120) induced by the four introgressed polymorphisms obtained using these three approaches was dependent on the AVKs used but were highly correlated among the three approaches. CONCLUSION: The four introgressed polymorphisms were clearly the cause of the strong resistant phenotype observed in the field. In the context of strong selection pressure due to the extensive use of AVKs, this resistant phenotype may explain the widespread distribution of this genotype from Spain to Germany. © 2016 Society of Chemical Industry.

Evidence of a target resistance to antivitamin K rodenticides in the roof rat Rattus rattus: identification and characterisation of a novel Y25F mutation in the Vkorc1 gene.

BACKGROUND: In spite of intensive use of bromadiolone, rodent control was inefficient on a farm infested by rats in Zaragoza, Spain. While metabolic resistance was previously described in this rodent species, the observation of a target resistance to antivitamin K rodenticides had been poorly documented in Rattus rattus. RESULTS: From rats trapped on the farm, cytochrome b and Vkorc1 genes were amplified by PCR and sequenced in order to identify species and detect potential Vkorc1 mutations. VKORC1-deduced amino acid sequences were thus expressed in Pichia pastoris, and inhibition constants towards various rodenticides were determined. The ten rats trapped on the farm were all identified as R. rattus. They were found to be homozygous for the g.74A>T nucleotide replacement in exon 1 of the Vkorc1 gene, leading to p.Y25F mutation. This mutation led to increased apparent inhibition constants towards various rodenticides, probably caused by a partial loss of helical structure of TM4. CONCLUSION: The p.Y25F mutation detected in the Vkorc1 gene in R. rattus trapped on the Spanish farm is associated with the resistance phenotype to bromadiolone that has been observed. It is the first evidence of target resistance to antivitamin K anticoagulants in R. rattus.

Predictive factors for obtaining a correct therapeutic range using antivitamin K anticoagulants: a tertiary center experience of patient adherence to anticoagulant therapy.

BACKGROUND: Patient adherence is an essential factor in obtaining efficient oral anticoagulation using vitamin K antagonists (VKAs), a situation with a narrow therapeutic window. Therefore, patient education and awareness are crucial for good management. Auditing the current situation would help to identify the magnitude of the problem and to build tailored education programs for these patients. METHODS: This study included 68 hospitalized chronically anticoagulated patients (mean age 62.6±13.1 years; males, 46%) who responded to a 26-item questionnaire to assess their knowledge on VKA therapy management. Laboratory and clinical data were used to determine the international normalized ratio (INR) at admission, as well as to calculate CHA2DS2-VASC and HAS-BLED scores for patients with atrial fibrillation. RESULTS: The majority of patients (62%) were receiving VKA for atrial fibrillation, the others for a mechanical prosthesis and previous thromboembolic disease or stroke. In the atrial fibrillation group, the mean CHA2DS2-VASC score was 3.1±1.5, while the average HAS-BLED score was 1.8±1.2. More than half of the patients (53%) had an INR outside of the therapeutic range at admission, with the majority (43%) having a low INR. A correct INR value was predicted by education level (higher education) and the diagnostic indication (patients with mechanical prosthesis being best managed). Patients presenting with a therapeutic INR had a trend toward longer treatment duration than those outside the therapeutic range (62±72 months versus 36±35 months, respectively, P=0.06). There was no correlation between INR at admission and the patient's living conditions, INR monitoring frequency, and bleeding history. CONCLUSION: In a tertiary cardiology center, more than half of patients receiving VKAs are admitted with an INR falling outside the therapeutic range, irrespective of the bleeding or embolic risk. Patients with a mechanical prosthesis and complex antithrombotic regimens appear to be the most careful with INR monitoring, especially if they have a higher level of education. Identifying patient groups with the lowest time interval spent in the therapeutic range could help attending physicians educate patients focusing on specific awareness issues.

[Anticoagulation in the aged patient with atrial fibrillation: What are prescribing cardiologists, geriatricians and general practitioners?]. / L'anticoagulation du patient âgé en fibrillation atriale: que prescrivent les cardiologues, les gériatres et les médecins généralistes?

OBJECTIVE: To assess prescribing of anticoagulants in atrial fibrillation (AF) in the elderly, both a quantitative point of view (rate of anticoagulation) and qualitative (type of anticoagulation). Determinants of prescribing and non-prescribing were also analysed. METHODS: Prospective survey of practice, based on one clinical case and questionnaire conducted in 60 practitioners (20 cardiologists [C], 20 geriatricians [G] and 20 general practitioners [GP]). RESULTS: In reading the clinical case, 88.3% of physicians would have initiated a treatment; three types of treatments would have been chosen: AVK (68.3%), ODA (20.0%) and platelet antiaggregant (11.7%). Criteria taken into account to initiate anticoagulation varied according to the specialty. Cardiologists considered more the age criteria (C: 95.0%, G: 75.0%, MG: 60.0%; P<0.05), diabetes (C: 90.0%, G: 60.0%, MG: 55.0%; P<0.05), hypertension (C: 85.0%, G: 55.0%, MG: 60.0%; P<0.05) and female gender (C: 80.0%, G: 35.0%, MG: 25.0%; P<0.05). The quality of renal function was however a more secondary criteria (C: 15.0%, G: 5.0%, MG: 0.0%; P<0.05). General practitioners considered most frequently the presence of underlying heart disease (C: 35.0%, G: 5.0%, MG: 45.0%; P<0.05) as well as usual cardiovascular risk factors (overweight, dyslipidaemia; P<0.05). Risk of bleeding, however, was observed by 76.7% of physicians in the clinical situation presented (C: 70.0%, G: 75.0%, MG: 85.0%; P<0.05). CONCLUSION: This survey confirms that the FA remains under anticoagulated in the elderly and the barriers to the prescription of oral anticoagulation are often without rational basis.

Stroke Prevention in Atrial Fibrillation - The Use of NOACs in Everyday Clinical Practice.

Non-antivitamin K oral anticoagulants (NOACs) have recently emerged as a new class of antithrombotic drugs. Four large-scale, randomised controlled trials (RCT) accredited dabigatran, rivaroxaban and edoxaban with evident advantages for stroke prevention in atrial fibrillation (AF) compared with warfarin. The superiority concerns not only the manageability but also the antithrombotic efficacy and safety. Aspects of real-life clinical experience with NOAC for stroke prevention in AF are analysed in an attempt to underline some practical differences. If at present the individualisation of the NOAC class drugs is still a subject of debate it is probable that in the near future we will be able to adapt the drug and dosages to individual patient's profile.

[Anticoagulation in atrial fibrillation in the elderly: the geriatrician point of view with a focus on the direct oral anticoagulants]. / L'anticoagulation dans la fibrillation atriale du sujet âgé : point de vue du gériatre avec un focus sur les anticoagulants oraux directs.

Prescribing anticoagulant therapy when the CHA2DS2-VASc score is ≥ 1 prevents strokes secondary to non-valvular atrial fibrillation (AF). However, it is important to remember that whether the aged population has the highest risk of stroke in case of AF, under anticoagulant therapy this population is also at the highest risk of bleeding. Vitamin K antagonists were for decades the molecules of reference with benefits even after 75 years of age. The direct oral anticoagulants have overcome the biological constraints inherent to monitoring vitamin K antagonists and provide a more stable pharmacological action with a limited number of drug-drug interactions. However, the widespread use of these molecules in the older population remains controversial. In this review article, indications and modalities of administration of anticoagulant therapy in the elderly will be detailed and discussed on the basis of the most recent recommendations proposed in particular by the European Society of Cardiology. Particular attention will be paid to new oral anticoagulant therapies compared with vitamin K antagonists and antiplatelet agents.

[Risk factors of serious bleeding among ambulatory patients taking antivitamin K aged 75 and over]. / Les déterminants d'hémorragies graves des sujets ambulatoires âgés de 75ans et plus sous antivitamine K.

The benefits of anti-vitamin K (AVK) drugs have been acknowledged in several indications. Such indications increasing with increasing age, AVK prescriptions also increases with age. At the same time, conditions involving significant bleeding are common in this elderly population. It is thus essential to recognize the determining factors. This study included all patients taking AVK drugs aged 75 years and older who sought emergency care at the Cochin Hospital from January to December 2011 for significant bleeding. These patients were compared with a cohort of patients aged 75 years or older who were taking AVK drugs and who were admitted to the same unit during the same time period for other reasons. The case-control comparison included demographic data, comorbidity factors, multiple medications, emergency measured INR, and CHA2DS2VASC level. The hemorrhagic risk was evaluated by HEMORR2HAGES and HAS-BLED. A total of 34 patients were studied and compared with 70 case-controls. The Charlson comorbidity index was higher in patients than case-controls (P<0.05), with a much higher hemorrhagic risk for scores ≥ 9 (OR=2.5; P<0.05). Multiple medication was also more predominant in patients (P<0.05). The risk of serious hemorrhage was also higher when the hemorrhagic scores were high, especially for HEMORR2HAGES (P<0.0001) and HAS-BLED (P<0.001). The risk of serious hemorrhage in elderly outpatients taking AVK drugs is related to their higher comorbidity and hemorrhagic levels which need to be evaluated before starting or stopping AVK treatment.

New insights into the catalytic mechanism of vitamin K epoxide reductase (VKORC1) - The catalytic properties of the major mutations of rVKORC1 explain the biological cost associated to mutations.

The systematic use of antivitamin K anticoagulants (AVK) as rodenticides caused the selection of rats resistant to AVKs. The resistance is mainly associated to genetic polymorphisms in the Vkorc1 gene encoding the VKORC1 enzyme responsible for the reduction of vitamin K 2,3-epoxide to vitamin K. Five major mutations, which are responsible for AVK resistance, have been described. Possible explanations for the biological cost of these mutations have been suggested. This biological cost might be linked to an increase in the vitamin K requirements. To analyze the possible involvement of VKORC1 in this biological cost, rVKORC1 and its major mutants were expressed in Pichia pastoris as membrane-bound proteins and their catalytic properties were determined for vitamin K and 3-OH-vitamin K production. In this report, we showed that mutations at Leu-120 and Tyr-139 dramatically affect the vitamin K epoxide reductase activity. Moreover, this study allowed the detection of an additional production of 3-hydroxyvitamin K for all the mutants in position 139. This result suggests the involvement of Tyr-139 residue in the second half-step of the catalytic mechanism corresponding to the dehydration of vitamin K epoxide. As a consequence, the biological cost observed in Y139C and Y139S resistant rat strains is at least partially explained by the catalytic properties of the mutated VKORC1 involving a loss of vitamin K from the vitamin K cycle through the formation of 3-hydroxyvitamin K and a very low catalytic efficiency of the VKOR activity.

Drug eluting stent implantation in patients requiring concomitant vitamin K antagonist therapy. One-year outcome of the worldwide e-SELECT registry.

BACKGROUND: Outcome of sirolimus-eluting stent (SES) in patients treated with an antivitamin K (VKA) agent before the PCI procedure is unknown. METHODS: A total of 7651 patients were selected among 15,147 recipients of SES, included in the worldwide e-SELECT registry, only from those centers which included at least one patient requiring VKA: 296 were pretreated with a VKA agent (VKA group), whereas 7355 patients from the same enrolling medical centers were not (NON-VKA group). The rates of 1) major adverse cardiac events (MACE), including all-cause deaths, myocardial infarction (MI) and target lesion revascularization, 2) stent thrombosis (ST) and 3) major bleeding (MB) in the 2 study groups were compared at 1, 6 and 12 months. RESULTS: The patients in VKA group were on average older as compared to those in NON-VKA group (67.7 ± 9.9 vs.62.9 ± 10.7, P<0.001). The indications for pre-procedural anticoagulation were atrial fibrillation in 177 (59.8%), presence of a prosthetic valve in 21 (7.1%), embolization of cardiac origin in 17 (5.7%), pulmonary embolism or deep vein thrombosis in 17 (5.7%), and miscellaneous diagnoses in 64 (21.6%) patients. At 1 year, the rates of MACE and MB were higher in the VKA vs. the NON-VKA group (8.3% and 3% vs. 5.3% and 1.2%, P<0.04 and P<0.002, respectively). The 1-year rates of definite and probable ST were remarkably low in both groups (0.38% vs. 1.1%, p=0.4). CONCLUSIONS: Selected patients anticoagulated with VKA agent may safely undergo SES implantation. Those patients may receive a variety of APT regimen at the cost of a moderate increased risk of MB.