Role of Noninvasive Urinary Prothrombin Fragment 1 + 2 to Measure Blood Coagulation Indices and Dose of Acenocoumarol.

PF1 + 2 plasma levels are a crucial indicator for assessing anticoagulant action in individuals receiving anticoagulant treatment. Urine also has PF1 + 2 levels due to its molecular size. Hence, the present study aims to measure urinary prothrombin fragment 1 + 2 (uPF1 + 2) in patients taking anticoagulants in order to divulge a noninvasive surrogate marker of PT-INR of blood coagulopathy. A total of 205 people participated in the study: 104 patients on acenocoumarol (AC) and 101 healthy controls (HC). Clinical parameters, including PT-INR, urinary creatinine, etc., were measured in all subjects. To evaluate uPF1 + 2 in samples, MALDI-TOF-MS, Western blot analysis, and ELISA tests were used. The MALDI-TOF-MS results showed the presence of uPF1 + 2 in both AC and HC urine samples. The Western blot, ELISA experiment, and unpaired t test results displayed that the patients with AC had significantly increased levels of uPF1 + 2 compared to HC. A regression study showed a strong positive relation between blood-based PT-INR and uPF1 + 2. ROC validation also revealed the clinical efficacy of uPF1 + 2. For the goal to monitor anticoagulant medication, the present study highlights PF1 + 2, which describes the overall hemostatic capacity and might be utilized in addition to or instead of PT-INR.

Acenocoumarol Exerts Anti-Inflammatory Activity via the Suppression of NF-κB and MAPK Pathways in RAW 264.7 Cells.

The repurposing of already-approved drugs has emerged as an alternative strategy to rapidly identify effective, safe, and conveniently available new therapeutic indications against human diseases. The current study aimed to assess the repurposing of the anticoagulant drug acenocoumarol for the treatment of chronic inflammatory diseases (e.g., atopic dermatitis and psoriasis) and investigate the potential underlying mechanisms. For this purpose, we used murine macrophage RAW 264.7 as a model in experiments aimed at investigating the anti-inflammatory effects of acenocoumarol in inhibiting the production of pro-inflammatory mediators and cytokines. We demonstrate that acenocoumarol significantly decreases nitric oxide (NO), prostaglandin (PG)E2, tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-1ß levels in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. Acenocoumarol also inhibits the expression of NO synthase (iNOS) and cyclooxygenase (COX)-2, potentially explaining the acenocoumarol-induced decrease in NO and PGE2 production. In addition, acenocoumarol inhibits the phosphorylation of mitogen-activated protein kinases (MAPKs), c-Jun N terminal kinase (JNK), p38 MAPK, and extracellular signal-regulated kinase (ERK), in addition to decreasing the subsequent nuclear translocation of nuclear factor κB (NF-κB). This indicates that acenocoumarol attenuates the macrophage secretion of TNF-α, IL-6, IL-1ß, and NO, inducing iNOS and COX-2 expression via the inhibition of the NF-κB and MAPK signaling pathways. In conclusion, our results demonstrate that acenocoumarol can effectively attenuate the activation of macrophages, suggesting that acenocoumarol is a potential candidate for drug repurposing as an anti-inflammatory agent.

Clinical outcomes of nonvitamin K oral anticoagulants and acenocoumarol for stroke prevention in contemporary practice: A population-based propensity-weighted cohort study.

AIMS: Acenocoumarol is a vitamin-K antagonist (VKA) primarily used in certain countries (e.g. India, Netherlands, Spain). The half-life of acenocoumarol is similar to that of non-VKA oral anticoagulants (NOAC), unlike warfarin, and this could affect comparative effectiveness and safety (CES). However, data on CES for NOAC come almost exclusively from studies using warfarin as the comparator. We aimed to assess outcomes of NOAC and acenocoumarol in people with non-valvular atrial fibrillation (NVAF) in real-world clinical practice. METHODS: This is a population-based retrospective cohort study. All new users of oral anticoagulants from November 2011 to December 2015 with NVAF were included (n = 41,560). Data were obtained by linking several health electronic records of the Valencia region, Spain. Incidence rates were estimated. We used the inverse probability of treatment weighted Cox analysis to control for indication bias when assessing the risk of effectiveness and safety outcomes for each NOAC compared with acenocoumarol. Several sensitivity analyses were performed. RESULTS: We did not find differences in the risk of mortality, ischaemic stroke or any gastrointestinal bleeding. However, we did find a decreased risk of intracranial haemorrhage for dabigatran (HR: 0.34, 95% CI 0.20-0.56) and rivaroxaban (HR: 0.55, 95% CI 0.35-0.85) as compared to acenocoumarol. In subanalyses, apixaban showed a higher risk of ischaemic stroke in high-risk persons (≥75 years and CHA2DS2-VASC score ≥ 2). CONCLUSIONS: No differences in clinical outcomes were found between NOAC and acenocoumarol overall, although dabigatran and rivaroxaban showed a lower risk of intracranial haemorrhage. Findings on the potential inferiority of specific NOAC in high-risk subgroups should be studied further.

Health literacy of patients on oral anticoagulation treatment- individual and social determinants and effect on health and treatment outcomes.

BACKGROUND: Assessment health literacy in people with cardiovascular health problems would facilitate the development of appropriate health strategies for the care and reduction of complications associated with oral anticoagulation therapy. AIM: To evaluate the relationship between health literacy and health and treatment outcomes (concordance with oral anticoagulants, Normalized Ratio control and occurrence of complications) in patients with cardiovascular pathology. METHODS: Observational, analytic and cross-sectional study carried out on 252 patients with cardiovascular pathology (atrial fibrillation, flutter or valve prosthesis), aged 50-85 years, accessing primary care services in Valencia (Spain) in 2018-2019. Variables referring to anticoagulant treatment with vitamin K antagonists (years of treatment, adequate control, polypharmacy and occurrence of complications, among others) and health literacy (Health Literacy Questionnaire) were analysed. RESULTS: All dimensions of health literacy were significantly related to the level of education (p < 0.02), social class (p < 0.02), an adequate control of acenocoumarol (p < 0.001), frequentation of health services (p < 0.001), information by patients to health professionals about anticoagulant treatment (p < 0.03), emergency care visits (p < 0.001) and unscheduled hospital admissions (p < 0.001). CONCLUSION: Health literacy has a relevant influence on the adequate self-management of anticoagulation treatment and the frequency of complications. The different dimensions that comprise health literacy play an important role, but the "social health support" dimension seems to be essential for such optimal self-management. TRIAL REGISTRATION: ACC-ACE-2016-01. Registration date: December 2015.

Comparison of Anticoagulation Quality between Acenocoumarol and Warfarin in Patients with Mechanical Prosthetic Heart Valves: Insights from the Nationwide PLECTRUM Study.

Vitamin K antagonists are indicated for the thromboprophylaxis in patients with mechanical prosthetic heart valves (MPHV). However, it is unclear whether some differences between acenocoumarol and warfarin in terms of anticoagulation quality do exist. We included 2111 MPHV patients included in the nationwide PLECTRUM registry. We evaluated anticoagulation quality by the time in therapeutic range (TiTR). Factors associated with acenocoumarol use and with low TiTR were investigated by multivariable logistic regression analysis. Mean age was 56.8 ± 12.3 years; 44.6% of patients were women and 395 patients were on acenocoumarol. A multivariable logistic regression analysis showed that patients on acenocoumarol had more comorbidities (i.e., ≥3, odds ratio (OR) 1.443, 95% confidence interval (CI) 1.081-1.927, p = 0.013). The mean TiTR was lower in the acenocoumarol than in the warfarin group (56.1 ± 19.2% vs. 61.6 ± 19.4%, p < 0.001). A higher prevalence of TiTR (<60%, <65%, or <70%) was found in acenocoumarol users than in warfarin ones (p < 0.001 for all comparisons). Acenocoumarol use was associated with low TiTR regardless of the cutoff used at multivariable analysis. A lower TiTR on acenocoumarol was found in all subgroups of patients analyzed according to sex, hypertension, diabetes, age, valve site, atrial fibrillation, and INR range. In conclusion, anticoagulation quality was consistently lower in MPHV patients on acenocoumarol compared to those on warfarin.

Clinical Impact of the Time in Therapeutic Range on Early Hospital Readmission in Patients with Acute Heart Failure Treated with Oral Anticoagulation in Internal Medicine.

Background and objectives: Patients with heart failure (HF) often present with non-valvular atrial fibrillation and require oral anticoagulation with coumarin anticoagulants such as acenocoumarol. The objective of this study was to evaluate the relationship between time in therapeutic range (TTR) and the risk of early readmission. Materials and Methods: A retrospective descriptive study was carried out on hospitalized patients with a diagnosis of HF between 2014 and 2018 who had adverse effects due to oral anticoagulation with acenocoumarol (underdosing, overdosing, or hemorrhage). Clinical, analytical, therapeutic, and prognostic variables were collected. TTR is defined as the duration of time in which the patient's International Normalized Ratio (INR) values were within a desired range. Early readmission was defined as readmission within 30 days after hospital discharge. Patients were divided into two groups depending on whether or not they had a TTR less than 60% (TTR < 60%) over the 6 months prior to the adverse event. Results: In the cohort of 304 patients, the mean age was 82 years, 59.9% of the patients were female, and 54.6% had a TTR < 60%. Patients with TTR < 60% had a higher HAS-BLED score (4.04 vs. 2.59; p < 0.001) and INR (6 vs. 5.31; p < 0.05) but lower hemoglobin (11.67 vs. 12.22 g/dL; p < 0.05). TTR < 60% was associated with early readmission after multivariate analysis (OR: 2.05 (CI 95%: 1.16-3.61)). They also had a higher percentage of hemorrhagic events and in-hospital mortality but without reaching statistical significance. Conclusions: Patients with HF and adverse events due to acenocoumarol often have poor INR control, which is independently associated with a higher risk of early readmission.

Risk of bradyarrhythmia related to ticagrelor: A systematic review and meta-analysis.

CONTEXT: Ticagrelor was related to bradycardia in DISPERSE-II trial. This risk has been integrated into the European risk-management plan, and its use is warned in at-risk patients. Nevertheless, this risk was not systematically assessed nor measured. OBJECTIVES: To estimate the risk of bradyarrhythmia associated with ticagrelor. STUDY DESIGN: Systematic review and meta-analysis. DATA-SOURCE: MEDLINE, Scopus, Cochrane Central Register of Controlled Trials, ISI web of Science, clinicaltrial.gov, clinicaltrialsregister.eu. STUDY SELECTION: Randomized controlled trials (RCTs) and observational studies in patients treated with ticagrelor or comparator(s). META-ANALYSIS: Risk of bias in each RCT was assessed using Cochrane tool. Relative Risks (RR) with 95 % confidence intervals (95 %CI) were calculated for each RCT, and pooled using fixed-effect or random-effects models, when appropriate. Subgroup and sensitivity analyses were performed. A potential publication bias was searched. RESULTS: Among 82 eligible studies, event data were missing for 56 studies, due to detected reporting bias (i.e. inability to confirm zero events). Fifteen RCTs were selected and the combined RR of bradyarrhythmia was 1.15 (95 %CI 1.05-1.26), and 1.29 (1.02-1.65) for severe bradyarrhythmia. The risk appeared to be dose dependent. Restricting the analysis only to RCTs performed in patients without previous bradyarrhythmia resulted in a non-increased risk. CONCLUSION: This meta-analysis confirmed the risk of bradyarrhythmia or severe bradyarrhythmia related to ticagrelor, and its use in patients without previous bradycardia was effective in preventing it. The evidence coming from this meta-analysis was low to moderate due to missing outcome in 2/3 of eligible studies. Waiting for access to these data, the use of ticagrelor in patients with risk factors of bradycardias should be avoided.

Drug-drug interactions with metronidazole and itraconazole in patients using acenocoumarol.

PURPOSE: Various population-based cohort studies have shown that antimicrobial agents increase the risk of overanticoagulation in patients using coumarins. In this study, we assessed this association in hospitalized patients. METHODS: We included all patients hospitalized in the Spaarne Gasthuis (Haarlem/Hoofddorp, the Netherlands), who started using an antimicrobial agent during acenocoumarol treatment or vice versa between 1 January 2015 and 1 July 2019. Patients were followed from start of concomitant therapy until 48 h after termination of the concomitant therapy or discharge, whichever came first. We analyzed the association between the antimicrobial agents and the risk of overanticoagulation, defined as an interpolated INR above 6, using Cox regression analysis. We corrected for multiple testing with the Bonferroni correction. Patients who started using acenocoumarol and amoxicillin/clavulanic acid were used as reference group. RESULTS: In the study population, sixteen antimicrobial agents were started frequently concomitantly with acenocoumarol treatment. We included 2157 interaction episodes in 1172 patients. Patients who started using the combination of co-trimoxazole (HR 3.76; 95% CI 1.47-9.62; p = 0.006), metronidazole (HR 2.55; 95% CI 1.37-4.76; p = 0.003), or itraconazole (HR 4.11; 95% CI 1.79-9.45; p = 0.001) concomitantly with acenocoumarol treatment had an increased risk of overanticoagulation compared with patients using acenocoumarol and amoxicillin/clavulanic acid concomitantly. The associations for metronidazole (p = 0.045) and itraconazole (p = 0.015) remained statistically significant after correction for multiple testing. CONCLUSION: Co-trimoxazole, metronidazole, and itraconazole increase the risk of overanticoagulation in patients using acenocoumarol. These combinations should be avoided if possible or otherwise acenocoumarol doses should be reduced and INR measured more frequently.

Resolution of acenocoumarol-associated calciphylaxis with drug withdrawal.

Calciphylaxis is a syndrome of cutaneous ischaemic necrosis and ulceration due to arteriolar calcification with subsequent thrombosis, which rarely presents in patients without terminal kidney disease. Recently, several reports of coumarins-associated calciphylaxis have stressed the relevance of anticoagulant therapy as an important risk factor for the development of this condition. We report five cases of acenocoumarol-associated, biopsy-proven calciphylaxis in women aged between 64 and 92 years. The drug had been prescribed for atrial fibrillation and was taken without interruption from 14 to 224 months. Lesions were present for months in all cases and were resistant to multiple therapeutic options, but they resolved only with simple wound care measures 6-14 months after changing the anticoagulant therapy.

Influence of genetic and non-genetic factors on acenocoumarol maintenance dose requirement in a Tunisian population.

PURPOSE: We aimed to study potential variables involved in interindividual variability to acenocoumarol (AC) response in order to establish a pharmacogenetic algorithm (PA) that includes clinical and genetic factors to predict adequate AC dose to stabilize anticoagulation in a cohort of Tunisian patients. METHODS: Genotyping of the CYP2C9, VKORC1, CYP4F2, and CALU polymorphisms was conducted on 246 patients using PCR-RFLP technique. AC normalized maintenance dose (NMD): ((mean maintenance dose/international normalized ratio (INR)) equilibrium) was calculated. The statistical study was carried out with SPSS V20. RESULTS: A significant correlation was found between age, BMI, and daily AC dose (r = - 0.397; p < 0.001 and r = 0.215; p = 0.001, respectively). The carriers of mutated alleles CYP2C9*2 or CYP2C9*3 or VKORC1 haplotypes (H1 and H7) were associated with AC hyper-sensibility. After adjustment to potential covariates, these patients presented supra-therapeutic INR during treatment period and needed low AC dose (ORs* = 0.28 [0.06-0.60], p = 0.004; ORs* = 0.12 [0.04-0.05], p < 0.001; ORs* = 0.45 [0.24-0.84], p = 0.01; and ORs* = 0.28 [0.06-0.98], p = 0.049, respectively). However, carriers of VKORC1 haplotypes (H3 and H12) or mutated alleles CYP4F2 (rs2108622) or CALU (rs1043550) tend to resist to treatment, hence long period of therapy initiation, and must be treated with high AC dose (ORs* = 2.67 [81.12-5.91], p = 0.013; ORs* = 8.76 [1.07-76.26], p = 0.019; ORs* = 3.12 [1.01-9.63], p = 0.047; and ORs* = 3.96 [1.41-11.09], p = 0.009, respectively). A final multivariate regression model explained 48.1% of the global interindividual variability in AC dose requirement. CONCLUSION: The PA demonstrated that VKORC1 and CYP2C9 polymorphisms contribution was more important than clinical factors. Applying the PA would allow dose adjustment to treat patients in a personalized manner.

Therapeutic Effect of Low Doses of Acenocoumarol in the Course of Ischemia/Reperfusion-Induced Acute Pancreatitis in Rats.

Intravascular activation of coagulation is observed in acute pancreatitis and is related to the severity of this inflammation. The aim of our study was to evaluate the impact of acenocoumarol therapy on the course of acute pancreatitis induced in male rats by pancreatic ischemia followed by reperfusion. Acenocoumarol at a dose of 50, 100, or 150 µg/kg/dose was administered intragastrically once a day, starting the first dose 24 h after the initiation of pancreatic reperfusion. RESULTS: Histological examination showed that treatment with acenocoumarol reduces pancreatic edema, necrosis, and hemorrhages in rats with pancreatitis. Moreover, the administration of acenocoumarol decreased pancreatic inflammatory infiltration and vacuolization of pancreatic acinar cells. These findings were accompanied with a reduction in the serum activity of lipase and amylase, concentration of interleukin-1ß, and plasma d-Dimer concentration. Moreover, the administration of acenocoumarol improved pancreatic blood flow and pancreatic DNA synthesis. Acenocoumarol given at a dose of 150 µg/kg/dose was the most effective in the treatment of early phase acute pancreatitis. However later, acenocoumarol given at the highest dose failed to exhibit any therapeutic effect; whereas lower doses of acenocoumarol were still effective in the treatment of acute pancreatitis. CONCLUSION: Treatment with acenocoumarol accelerates the recovery of ischemia/reperfusion-induced acute pancreatitis in rats.

Effectiveness and safety of dabigatran versus acenocoumarol in 'real-world' patients with atrial fibrillation.

AIMS: Randomized trials showed non-inferior or superior results of the non-vitamin-K-antagonist oral anticoagulants (NOACs) compared with warfarin. The aim of this study was to assess the effectiveness and safety of dabigatran (direct thrombin inhibitor) vs. acenocoumarol (vitamin K antagonist) in patients with atrial fibrillation (AF) in daily clinical practice. METHODS AND RESULTS: In this observational study, we evaluated all consecutive patients who started anticoagulation because of AF in our outpatient clinic from 2010 to 2013. Data were collected from electronic patient charts. Primary outcomes were stroke or systemic embolism and major bleeding. Propensity score matching was applied to address the non-randomized design. In total, 920 consecutive AF patients were enrolled (442 dabigatran, 478 acenocoumarol), of which 2 × 383 were available for analysis after propensity score matching. Mean follow-up duration was 1.5 ± 0.56 year. The mean calculated stroke risk according to the CHA2DS2-VASc score was 3.5%/year in dabigatran vs. 3.7%/year acenocoumarol-treated patients. The actual incidence rate of stroke or systemic embolism was 0.8%/year [95% confidence interval (CI): 0.2-2.1] vs. 1.0%/year (95% CI: 0.4-2.1), respectively. Multivariable analysis confirmed this lower but non-significant risk in dabigatran vs. acenocoumarol after adjustment for the CHA2DS2-VASc score [hazard ratio (HR)dabigatran = 0.72, 95% CI: 0.20-2.63, P = 0.61]. According to the HAS-BLED score, the mean calculated bleeding risk was 1.7%/year in both groups. Actual incidence rate of major bleeding was 2.1%/year (95% CI: 1.0-3.8) in the dabigatran vs. 4.3%/year (95% CI: 2.9-6.2) in acenocoumarol. This over 50% reduction remained significant after adjustment for the HAS-BLED score (HRdabigatran = 0.45, 95% CI: 0.22-0.93, P = 0.031). CONCLUSION: In 'real-world' patients with AF, dabigatran appears to be as effective, but significantly safer than acenocoumarol.

Adequacy of preadmission oral anticoagulation with vitamin K antagonists and ischemic stroke severity and outcome in patients with atrial fibrillation.

It is unclear whether vitamin K antagonists affect stroke severity and outcome in patients with atrial fibrillation (AF). We aimed to evaluate this association. We prospectively studied 539 consecutive patients admitted with acute ischemic stroke (41.2 % males, age 78.9 ± 6.6 years). The severity of stroke was assessed at admission with the National Institutes of Health Stroke Scale (NIHSS). The outcome was assessed with dependency rates at discharge (modified Rankin scale 2-5) and with in-hospital mortality. 177 patients had a history of AF. The median NIHSS at admission did not differ between patients on acenocoumarol with INR 2.0-3.0, on acenocoumarol with INR < 2.0, on single antiplatelet treatment, on dual antiplatelet treatment, or on no treatment [4 (range 0-26), 13 (0-39), 8 (0-33), 3 (2-23) and 7 (0-33), respectively; p = 0.433]. Dependency rates were lower in patients on acenocoumarol with INR 2.0-3.0 or on dual antiplatelet treatment than in those on acenocoumarol with INR < 2.0, single antiplatelet treatment, or no treatment (20.0, 22.2, 61.5, 58.7 and 68.0 %, respectively; p = 0.024). Independent predictors of dependency were age, NIHSS at admission and history of ischemic stroke. In-hospital mortality did not differ between patients on acenocoumarol with INR 2.0-3.0, on acenocoumarol with INR < 2.0, on single antiplatelet treatment, on dual antiplatelet treatment, or on no treatment (7.7, 18.2, 16.1, 16.7 and 22.2 %, respectively; p = 0.822). In conclusion, optimally anticoagulated patients with AF have more favorable functional outcome after stroke and a trend for less severe stroke whereas patients with subtherapeutic anticoagulation have similar stroke severity and outcome with those on no treatment.

Decreased INR after acenocoumarol, ombitasvir/paritaprevir/ritonavir and dasabuvir co-administration.

WHAT IS KNOWN AND OBJECTIVE: Limited data are available on co-administration of acenocoumarol with direct-acting antiviral agents for chronic hepatitis C virus infection. CASE SUMMARY: We report a case of a patient who required a significant increase in acenocoumarol weekly dose probably due to an interaction with ombitasvir/paritaprevir/ritonavir and/or dasabuvir. A causality assessment of the drug-drug interaction leading to a reduced INR was conducted according to the Naranjo algorithm. A score of 6 suggested that the adverse drug reaction was probable. WHAT IS NEW AND CONCLUSION: Because of possible INR abnormalities during the concomitant use of acenocoumarol, ombitasvir/paritaprevir/ritonavir and dasabuvir, clinicians should closely monitor INR values.

Effects of anti-aggregant, anti-inflammatory and anti-coagulant drug consumption on the preparation and therapeutic potential of plasma rich in growth factors (PRGF).

The prevalence and incidence of trauma-related injuries, coronary heart disease and other chronic diseases increase dramatically with age. This population sector is therefore a regular consumer of different types of drugs that may affect platelet aggregation and the coagulation cascade. We have evaluated whether the consumption of acetylsalicylic acid, acenocoumarol, glucosamine sulfate and chondroitin sulfate, and therefore their presence in blood, could interfere with the preparation and biological outcomes of plasma rich in growth factors (PRGF). Clotting time, clot retraction and platelet activation of PRGF was evaluated. PRGF growth factor content and the release of different biomolecules by tendon fibroblasts were also quantified, as well as cell proliferation and cell migration. The preparation and biological potential of PRGF is not affected by the intake of the evaluated drugs, and solely its angiogenic potential and its capacity to induce HA and fibronectin synthesis, is reduced in patients taking anti-coagulants.

Probable interaction between acenocoumarol and levofloxacin: a case series.

WHAT IS KNOWN AND OBJECTIVE: To report five cases with a probable interaction between acenocoumarol and levofloxacin. CASE DESCRIPTION: In five patients on long-term acenocoumarol treatment who had had stable international normalized ratios for at least 6 months, sudden erratic changes in the values of these ratios were observed after 1.5-8 days of concomitant levofloxacin treatment with no other apparent cause. WHAT IS NEW AND CONCLUSIONS: Closer monitoring should be considered in patients with concomitant use of acenocoumarol and levofloxacin, especially elderly patients and those with renal dysfunction who seemed to suffer the interaction more severely.

Acenocoumarol Pharmacogenetic Dosing Algorithms and Their Application in Two Bulgarian Patients with Low Anticoagulant Requirements.

BACKGROUND: The anticoagulant therapy with acenocoumarol is generally associated with a high risk of bleeding and thromboembolic events. PURPOSE: We applied eight already existing acenocoumarol dosing algorithms to Bulgarian patients with low acenocoumarol dose requirements and investigated which of these algorithms would predict most precisely the dose anticoagulant. MATERIALS AND METHODS: Two patients with Bulgarian origin were referred to the outpatient clinical laboratory of "St. Ekaterina" University Hospital for Cardiovascular Surgery and Cardiology, Sofia, Bulgaria. After obtaining written informed consent, both patients were genotyped for polymorphisms in genes for Cytochrome P450 2C9 (CYP2C9), Vitamin K epoxide reductase (VKORC1), Apolipoprotein E (APOE), and Cytochrome P450 4F2 (CYP4F2). RESULTS: All applied acenocoumarol dosing algorithms predicted relatively similar doses of coumarin anticoagulant in both patients. However, van Schie et al.'s algorithm allowed more accurate calculation of the optimal dose in our patients with extremely low acenocoumarol requirements. Genotyping of selected polymorphic variants in CYP2C9 and VKORC1 showed that both patients were compound heterozygotes for CYP2C9 (CYP2C9*2/*3) and homozygotes for both variants in VKORC1 (VKORC1 1173 T/T, and VKORC1-1639 A/A). This combination of genotypes suggested high sensitivity to acenocoumarol leading to the low anticoagulant dose requirements (0.25 and 1 mg/day, respectively) needed to reach the target International Normalized Ratio of 2.5-3.5. CONCLUSIONS: The genotyping of polymorphic variants in VKORC1 and CYP2C9, together with clinical and demographic parameters, can serve for more precise definition of the individual starting and maintenance doses of coumarin derivatives in each patient.

Low dose dabigatran versus uninterrupted acenocoumarol for peri-procedural anticoagulation in atrial fibrillation catheter ablation.

BACKGROUND: Left atrial ablation for atrial fibrillation (AF) is associated with a transiently increased risk of thromboembolic and hemorrhagic events. We tested the hypothesis that the low dose dabigatran [110mg twice a day (bid)] can be safely used as an alternative to uninterrupted acenocoumarol for periprocedural anticoagulation in left atrial ablation procedures. METHODS AND RESULTS: A total of 149 consecutive patients undergoing pulmonary vein antral isolation for AF were included; 64 patients were on low dose dabigatran (110mg bid) and 85 patients were on acenocoumarol with therapeutic international normalized ratios. Two doses of dabigatran were withheld before the procedure and the drug was restarted 4hours after vascular hemostasis. Overall, the two groups were well-matched. Hemorrhagic and thromboembolic complications were similar in both groups within 90days from the procedure (4.7% for the dabigatran group versus 9.4% for the acenocoumarol group; P=0.275). Major hemorrhage occurred in 1.6% in the dabigatran group versus 3.5% in the acenocoumarol group (P=0.462). A single thromboembolic event occurred in the dabigatran group (1.6%) versus 2 (2.4%) in the acenocoumarol group (P=0.734). Despite higher doses of intraprocedural heparin (P<0.01), the mean activated clotting time was significantly lower in patients who were on dabigatran than those on acenocoumarol (P<0.01). CONCLUSIONS: The low dose dabigatran regimen provides safe and effective peri-procedural anticoagulation in patients undergoing left atrial ablation for AF compared with uninterrupted acenocoumarol therapy.

Beliefs about medicines in Dutch acenocoumarol and phenprocoumon users.

AIMS: Adherence to the generally complex regimen of coumarin derivatives is vital in order to keep patients in the adequate International Normalized Ratio range. Patients' beliefs about medicines are associated with the level of therapy adherence. Our first aim was to assess beliefs about coumarins. Secondly, we compared the beliefs about coumarins with the beliefs about other cardiovascular drugs. METHODS: The Beliefs about Medicines Questionnaire was used to assess medication beliefs. The questionnaire was completed by new users of coumarins indicated for venous thromboembolism or atrial fibrillation. A necessity score and a concerns score were calculated for all patients. The analyses were repeated for users of antihypertensive drugs or statins (not using coumarins). RESULTS: Three hundred and twenty patients were included in the analysis of the beliefs about coumarins. The mean necessity score was 15.3, the concerns score 12.3 and the necessity-concerns differential 3.0. Patients with venous thromboembolism (n = 71) had higher necessity scores than patients with atrial fibrillation (n = 249; 16.8 vs. 14.9, P < 0.001). The mean necessity score in 493 users of other cardiovascular drugs was 16.1, the concerns score 13.5 and the necessity-concerns differential 2.6. The necessity score was higher in chronic cardiovascular drug users (n = 192) than in new users (n = 301; 17.9 vs. 14.9, P < 0.001). CONCLUSIONS: Coumarin users score higher on the necessity scale than on the concerns scale, which is also the case in users of other cardiovascular drugs. Patients with atrial fibrillation have a less positive attitude towards these drugs than patients with venous thromboembolism, and could therefore benefit more from specific attention.