Background: The Framingham Study from 1991 showed a clear correlation between atrial fibrillation (AF) and ischemic stroke, where patients with AF had an almost fivefold increase in risk of stroke compared with patients without AF. Since then, several trials have evaluated different antithrombotic treatments to reduce the risk of stroke in patients with AF. Other trials have investigated factors that increase the risk of stroke in patients with AF and risk score systems have been developed to categorize patients into low or increased risk of stroke to help clinicians to decide which patients benefit from antithrombotic treatment and in whom it can be abstained, not to expose patients with low stroke risk to an increased risk of bleeding conferred by antithrombotic treatment. The aims of this thesis were: [1] to evaluate if a warfarin dosing algorithm can increase hit rate and decrease mean error compared with manually changed doses; [2] to assess the prevalence and net clinical benefit of aspirin as monotherapy for stroke prevention in AF; [3] to investigate the risk of thromboembolic and haemorrhagic complications within 30 days after electrical cardioversion (ECV) of AF in patients with and without oral anticoagulation (OAC) pre-treatment; and [4] to assess the proportion of patients discontinuing OAC after pulmonary vein isolation (PVI), identify factors predicting stroke after PVI and to investigate risk of complications after PVI with and without OAC. Materials and methods: All studies are retrospective and based on data from Swedish national quality registries. In paper I, data from Auricula was used to compare the resulting INR values after algorithmic warfarin dose suggestions and manually changed doses. In paper II data was extracted from the Swedish National Patient Register, the Dispensed Drugs Register and the Cause of Death Register. Patients with aspirin treatment were compared with patients without any antithrombotic treatment regarding risk of thromboembolic and haemorrhagic complications. In paper III data was collected from the Swedish National Patient Register and the Dispensed Drugs Register to examine risk of complications (thromboembolic and haemorrhagic events) within 30 days after cardioversion, comparing patients with and without oral anticoagulation pre-treatment. In paper IV data from six different Swedish national quality registries were used (Swedish Catheter Ablation Register, Auricula, Swedish National Patient Register, Dispensed Drugs Register, Cause of Death Register and Riksstroke). Patients undergoing pulmonary vein isolation (PVI) were investigated for adherence to guidelines regarding oral anticoagulation, predictors for stroke after PVI, as well as risk of ischemic stroke or intracranial haemorrhage after PVI in patients with and without treatment. Results: Paper I showed that a computerized dosing algorithm for warfarin in most cases perform as well or better compared with doses that have been changed manually, with a better hit-rate (0.72 vs. 0.67) and a lower mean error (0.44 vs. 0.48). Paper II showed that 32% of 182.678 patients with a diagnosis of AF were on monotherapy with aspirin for stroke prevention. A total of 115.185 patients were included, 58.671 with aspirin treatment and 56.514 without antithrombotic treatment at baseline. After stratification after CHA2DS2-VASc score and after multivariable adjustment, aspirin treatment did not confer a decrease in thromboembolic events. After propensity score mathcing, rate of ischemic stroke was 7.4%/year (95% CI 7.1-7.6) in aspirin treated patients and 6.6%/year (95% CI 6.4-6.9) in patients without antithrombotic treatment. In paper III 22.874 patients undergoing electrical cardioversion were included, 10.722 with and 12.152 without OAC pre-treatment. In patients with low stroke risk (CHA2DS2-VASc 0-1), no thromboembolic complication was seen within 30 days after cardioversion. In patients with CHA2DS2-VASc ≥2, the risk of thromboembolic complications was increased when no oral anticoagulation pre-treatment was used, results that remained after propensity score matching. No difference regarding haemorrhagic complications was seen. Paper IV included a total of 1585 patients undergoing PVI with a mean follow up of 2.6 years. Adherence to current guidelines regarding oral anticoagulation was good in patients with CHA2DS2-VASc ≥2. Previous ischemic stroke was a predictor for a new stroke after PVI. In patients with CHA2DS2-VASc ≥2 stroke risk was increased in patients discontinuing OAC compared to those continuing OAC (1,60%/year vs. 0.34%/year). Conclusion: Oral anticoagulation is still underutilized for prevention of stroke and systemic embolism in patients with atrial fibrillation. Patients with risk factors for stroke (CHA2DS2-VASc ≥2p) benefit from continuous oral anticoagulation treatment to prevent stroke, also in conjunction with electrical cardioversion and after pulmonary vein isolation. If warfarin is chosen, a computerised dosing algorithm can facilitate and standardize warfarin dosing and lead to better resulting INR values than manually changed doses. Aspirin should not be used for stroke prevention in patients with atrial fibrillation.

A anticoagulação inadequada pode ocasionar eventos tromboembólicos e hemorrágicos, representando um desafio para a medicina. A varfarina, anticoagulante oral de amplo uso, está associada a reações adversas graves, frequentes nos pacientes em tratamento com múltiplos fármacos. Objetivo: Este estudo pretende avaliar as potenciais interações medicamentosas com a varfarina, descrever e quantificar as intervenções farmacêuticas para minimizá-las, verificar o grau de aceitação da equipe médica em relação às intervenções e a repercussão no resultado do RNI. Método: Estudo de coorte, realizado entre os meses de agosto de 2009 a janeiro de 2010, envolvendo pacientes internados que iniciaram o tratamento com varfarina em duas unidades de clínica médica em um hospital universitário localizado no sul do Brasil. As potenciais interações medicamentosas com a varfarina (graves e moderadas) foram identificadas no sistema Drug-Reax, Micromedex Healthcare. Outras informações foram obtidas diretamente no prontuário. As intervenções com a equipe médica ocorreram por meio de registro em prontuário ou por informação verbal. O valor do RNI (Relação Normatizada Internacional) foi constantemente monitorado e serviu como medida do resultado da intervenção. Resultados: Foram acompanhados 202 pacientes. O total de medicamentos prescritos foi de 2071, com média de 10 (DP=3,6) por paciente. Todos pacientes apresentaram pelo menos uma interação medicamentosa potencial grave ou moderada com a varfarina, sendo a média de 3,6 (DP=1,6) por paciente. Pacientes com mais de 4 interações medicamentosas potenciais apresentaram maior risco para eventos hemorrágicos (RNI > 5 - RR = 2,57; IC95% 1,37–4,80). Foram identificadas 737 potenciais interações; 675 (91,5%) com possibilidade de potencializar o efeito anticoagulante e 29 (3,9%) de reduzir este efeito. Os medicamentos mais envolvidos em interações de potencialização foram enoxaparina (32,2%), sinvastatina (27,6%), omeprazol (22,5%) e tramadol (21,5%). Das intervenções realizadas com a equipe médica, 116 (57,4%) se deram através de registros em prontuário e 86 (42,6%) de forma verbal. Para 32 pacientes (15,8%) as intervenções não foram aceitas e estes apresentaram maior risco (RR = 2,17; IC95% 1,10 –4,27) para exame alterado (RNI > 5). Análise multivariada mostrou que idade, tempo de internação, apresentar 4 ou mais interações potenciais graves ou moderadas e não aceitar a intervenção farmacêutica contribuem significativamente para o paciente apresentar resultado de RNI > 5, o que implica em risco para eventos hemorrágicos. Conclusão: Interações medicamentosas graves e moderadas envolvendo a varfarina são muito comuns nos pacientes internados e estão associadas à maior risco do paciente apresentar RNI fora da faixa terapêutica desejada. A participação do farmacêutico no manejo das interações através de informações e orientações aos prescritores mostrou ter boa aceitação em nosso meio e parece contribuir para a segurança do paciente. / Introduction: Inadequate anticoagulation may cause bleeding and thromboembolic events, representing a challenge for medicine. Warfarin, an oral anticoagulant in wide use, has severe adverse reactions, common in patients taking multiple drugs. Objectives: This study aims to evaluate potential drug interactions with warfarin; to describe and quantify pharmaceutical interventions in order to minimize them; to assess the degree of acceptability by the medical team in relation to interventions as well as the impact on the outcome of the INR. Method: A Cohort study, done between August 2009 and January 2010 involving hospitalized patients who started warfarin therapy in two internal medicine units in a university hospital located in southern Brazil. Potential pDDIs with warfarin with warfarin (major and moderate) were identified in the online system Drug-Reax, Micromedex Healthcare. Additional information was obtained directly from medical records. Interventions with medical team were through medical record notes or verbal information. The value of the INR (international normalized ratio) was continuously monitored and served as a measure of the outcome of the intervention. Results: Two hundred and two inpatients were followed. The total number of prescribed drugs was 2071, with mean of 10 (SD = 3.6) per patient. All inpatients had at least one potential moderate or severe pDDIs with warfarin, the mean was 3.6 (SD = 1.6) per patient. Patients with more than four potential drug interactions showed a higher risk for hemorrhagic problems (INR> 5 - RR = 3.00, 95% CI 1.59-5.70). For 737 pDDIs identified, 675 (91.5%) may result in increased anticoagulation activity and 29 (3.9%) may reduce this effect. The drugs most commonly involved in these pDDIs were enoxaparin (32.2%), simvastatin (27.6%), omeprazole (22.5%) and tramadol (21.5%). The medical team’s intervention were 116 (57.4%) through medical records and 86 (42.6%) were orally. For 32 patients (15.8%), interventions were not accepted and they had higher risk (RR = 2.17; 95% CI 1.10 – 4.27) for amended exam (INR > 5). Multivariate analysis showed that age, length of hospital stay, having four or more major or moderate potential interactions and unwillingness to accept pharmaceutical intervention contribute significantly to the patient current values of INR> 5, which implies a risk of bleeding. Conclusion: Major and moderate drug interactions involving warfarin are very common in hospitalized patients and are associated with patient’s high risk of having an INR outside the target range. The collaboration of pharmacists in the management of interactions with information and guidance to physicians showed a good acceptance and seems to contribute to patient safety.

A anticoagulação inadequada pode ocasionar eventos tromboembólicos e hemorrágicos, representando um desafio para a medicina. A varfarina, anticoagulante oral de amplo uso, está associada a reações adversas graves, frequentes nos pacientes em tratamento com múltiplos fármacos. Objetivo: Este estudo pretende avaliar as potenciais interações medicamentosas com a varfarina, descrever e quantificar as intervenções farmacêuticas para minimizá-las, verificar o grau de aceitação da equipe médica em relação às intervenções e a repercussão no resultado do RNI. Método: Estudo de coorte, realizado entre os meses de agosto de 2009 a janeiro de 2010, envolvendo pacientes internados que iniciaram o tratamento com varfarina em duas unidades de clínica médica em um hospital universitário localizado no sul do Brasil. As potenciais interações medicamentosas com a varfarina (graves e moderadas) foram identificadas no sistema Drug-Reax, Micromedex Healthcare. Outras informações foram obtidas diretamente no prontuário. As intervenções com a equipe médica ocorreram por meio de registro em prontuário ou por informação verbal. O valor do RNI (Relação Normatizada Internacional) foi constantemente monitorado e serviu como medida do resultado da intervenção. Resultados: Foram acompanhados 202 pacientes. O total de medicamentos prescritos foi de 2071, com média de 10 (DP=3,6) por paciente. Todos pacientes apresentaram pelo menos uma interação medicamentosa potencial grave ou moderada com a varfarina, sendo a média de 3,6 (DP=1,6) por paciente. Pacientes com mais de 4 interações medicamentosas potenciais apresentaram maior risco para eventos hemorrágicos (RNI > 5 - RR = 2,57; IC95% 1,37–4,80). Foram identificadas 737 potenciais interações; 675 (91,5%) com possibilidade de potencializar o efeito anticoagulante e 29 (3,9%) de reduzir este efeito. Os medicamentos mais envolvidos em interações de potencialização foram enoxaparina (32,2%), sinvastatina (27,6%), omeprazol (22,5%) e tramadol (21,5%). Das intervenções realizadas com a equipe médica, 116 (57,4%) se deram através de registros em prontuário e 86 (42,6%) de forma verbal. Para 32 pacientes (15,8%) as intervenções não foram aceitas e estes apresentaram maior risco (RR = 2,17; IC95% 1,10 –4,27) para exame alterado (RNI > 5). Análise multivariada mostrou que idade, tempo de internação, apresentar 4 ou mais interações potenciais graves ou moderadas e não aceitar a intervenção farmacêutica contribuem significativamente para o paciente apresentar resultado de RNI > 5, o que implica em risco para eventos hemorrágicos. Conclusão: Interações medicamentosas graves e moderadas envolvendo a varfarina são muito comuns nos pacientes internados e estão associadas à maior risco do paciente apresentar RNI fora da faixa terapêutica desejada. A participação do farmacêutico no manejo das interações através de informações e orientações aos prescritores mostrou ter boa aceitação em nosso meio e parece contribuir para a segurança do paciente. / Introduction: Inadequate anticoagulation may cause bleeding and thromboembolic events, representing a challenge for medicine. Warfarin, an oral anticoagulant in wide use, has severe adverse reactions, common in patients taking multiple drugs. Objectives: This study aims to evaluate potential drug interactions with warfarin; to describe and quantify pharmaceutical interventions in order to minimize them; to assess the degree of acceptability by the medical team in relation to interventions as well as the impact on the outcome of the INR. Method: A Cohort study, done between August 2009 and January 2010 involving hospitalized patients who started warfarin therapy in two internal medicine units in a university hospital located in southern Brazil. Potential pDDIs with warfarin with warfarin (major and moderate) were identified in the online system Drug-Reax, Micromedex Healthcare. Additional information was obtained directly from medical records. Interventions with medical team were through medical record notes or verbal information. The value of the INR (international normalized ratio) was continuously monitored and served as a measure of the outcome of the intervention. Results: Two hundred and two inpatients were followed. The total number of prescribed drugs was 2071, with mean of 10 (SD = 3.6) per patient. All inpatients had at least one potential moderate or severe pDDIs with warfarin, the mean was 3.6 (SD = 1.6) per patient. Patients with more than four potential drug interactions showed a higher risk for hemorrhagic problems (INR> 5 - RR = 3.00, 95% CI 1.59-5.70). For 737 pDDIs identified, 675 (91.5%) may result in increased anticoagulation activity and 29 (3.9%) may reduce this effect. The drugs most commonly involved in these pDDIs were enoxaparin (32.2%), simvastatin (27.6%), omeprazole (22.5%) and tramadol (21.5%). The medical team’s intervention were 116 (57.4%) through medical records and 86 (42.6%) were orally. For 32 patients (15.8%), interventions were not accepted and they had higher risk (RR = 2.17; 95% CI 1.10 – 4.27) for amended exam (INR > 5). Multivariate analysis showed that age, length of hospital stay, having four or more major or moderate potential interactions and unwillingness to accept pharmaceutical intervention contribute significantly to the patient current values of INR> 5, which implies a risk of bleeding. Conclusion: Major and moderate drug interactions involving warfarin are very common in hospitalized patients and are associated with patient’s high risk of having an INR outside the target range. The collaboration of pharmacists in the management of interactions with information and guidance to physicians showed a good acceptance and seems to contribute to patient safety.

A anticoagulação inadequada pode ocasionar eventos tromboembólicos e hemorrágicos, representando um desafio para a medicina. A varfarina, anticoagulante oral de amplo uso, está associada a reações adversas graves, frequentes nos pacientes em tratamento com múltiplos fármacos. Objetivo: Este estudo pretende avaliar as potenciais interações medicamentosas com a varfarina, descrever e quantificar as intervenções farmacêuticas para minimizá-las, verificar o grau de aceitação da equipe médica em relação às intervenções e a repercussão no resultado do RNI. Método: Estudo de coorte, realizado entre os meses de agosto de 2009 a janeiro de 2010, envolvendo pacientes internados que iniciaram o tratamento com varfarina em duas unidades de clínica médica em um hospital universitário localizado no sul do Brasil. As potenciais interações medicamentosas com a varfarina (graves e moderadas) foram identificadas no sistema Drug-Reax, Micromedex Healthcare. Outras informações foram obtidas diretamente no prontuário. As intervenções com a equipe médica ocorreram por meio de registro em prontuário ou por informação verbal. O valor do RNI (Relação Normatizada Internacional) foi constantemente monitorado e serviu como medida do resultado da intervenção. Resultados: Foram acompanhados 202 pacientes. O total de medicamentos prescritos foi de 2071, com média de 10 (DP=3,6) por paciente. Todos pacientes apresentaram pelo menos uma interação medicamentosa potencial grave ou moderada com a varfarina, sendo a média de 3,6 (DP=1,6) por paciente. Pacientes com mais de 4 interações medicamentosas potenciais apresentaram maior risco para eventos hemorrágicos (RNI > 5 - RR = 2,57; IC95% 1,37–4,80). Foram identificadas 737 potenciais interações; 675 (91,5%) com possibilidade de potencializar o efeito anticoagulante e 29 (3,9%) de reduzir este efeito. Os medicamentos mais envolvidos em interações de potencialização foram enoxaparina (32,2%), sinvastatina (27,6%), omeprazol (22,5%) e tramadol (21,5%). Das intervenções realizadas com a equipe médica, 116 (57,4%) se deram através de registros em prontuário e 86 (42,6%) de forma verbal. Para 32 pacientes (15,8%) as intervenções não foram aceitas e estes apresentaram maior risco (RR = 2,17; IC95% 1,10 –4,27) para exame alterado (RNI > 5). Análise multivariada mostrou que idade, tempo de internação, apresentar 4 ou mais interações potenciais graves ou moderadas e não aceitar a intervenção farmacêutica contribuem significativamente para o paciente apresentar resultado de RNI > 5, o que implica em risco para eventos hemorrágicos. Conclusão: Interações medicamentosas graves e moderadas envolvendo a varfarina são muito comuns nos pacientes internados e estão associadas à maior risco do paciente apresentar RNI fora da faixa terapêutica desejada. A participação do farmacêutico no manejo das interações através de informações e orientações aos prescritores mostrou ter boa aceitação em nosso meio e parece contribuir para a segurança do paciente. / Introduction: Inadequate anticoagulation may cause bleeding and thromboembolic events, representing a challenge for medicine. Warfarin, an oral anticoagulant in wide use, has severe adverse reactions, common in patients taking multiple drugs. Objectives: This study aims to evaluate potential drug interactions with warfarin; to describe and quantify pharmaceutical interventions in order to minimize them; to assess the degree of acceptability by the medical team in relation to interventions as well as the impact on the outcome of the INR. Method: A Cohort study, done between August 2009 and January 2010 involving hospitalized patients who started warfarin therapy in two internal medicine units in a university hospital located in southern Brazil. Potential pDDIs with warfarin with warfarin (major and moderate) were identified in the online system Drug-Reax, Micromedex Healthcare. Additional information was obtained directly from medical records. Interventions with medical team were through medical record notes or verbal information. The value of the INR (international normalized ratio) was continuously monitored and served as a measure of the outcome of the intervention. Results: Two hundred and two inpatients were followed. The total number of prescribed drugs was 2071, with mean of 10 (SD = 3.6) per patient. All inpatients had at least one potential moderate or severe pDDIs with warfarin, the mean was 3.6 (SD = 1.6) per patient. Patients with more than four potential drug interactions showed a higher risk for hemorrhagic problems (INR> 5 - RR = 3.00, 95% CI 1.59-5.70). For 737 pDDIs identified, 675 (91.5%) may result in increased anticoagulation activity and 29 (3.9%) may reduce this effect. The drugs most commonly involved in these pDDIs were enoxaparin (32.2%), simvastatin (27.6%), omeprazole (22.5%) and tramadol (21.5%). The medical team’s intervention were 116 (57.4%) through medical records and 86 (42.6%) were orally. For 32 patients (15.8%), interventions were not accepted and they had higher risk (RR = 2.17; 95% CI 1.10 – 4.27) for amended exam (INR > 5). Multivariate analysis showed that age, length of hospital stay, having four or more major or moderate potential interactions and unwillingness to accept pharmaceutical intervention contribute significantly to the patient current values of INR> 5, which implies a risk of bleeding. Conclusion: Major and moderate drug interactions involving warfarin are very common in hospitalized patients and are associated with patient’s high risk of having an INR outside the target range. The collaboration of pharmacists in the management of interactions with information and guidance to physicians showed a good acceptance and seems to contribute to patient safety.

Introdução. Avaliar o conhecimento, de indivíduos em uso da terapia com anticoagulantes orais (TAO), é uma estratégia que profissionais da saúde podem utilizar para orientar o cuidado dispensado a estas pessoas. O uso de um instrumento psicometricamente válido e confiável é fundamental para garantir uma avaliação adequada. Objetivo. Construir e validar um instrumento para avaliar o conhecimento sobre a TAO. Método. Estudo metodológico e de corte transversal, que seguiu as seguintes etapas: elaboração dos itens, validação de face e conteúdo por um comitê de juízes, estudo piloto e aplicação do instrumento em uma amostra da população estudada. A amostra foi constituída de pacientes adultos, em uso de anticoagulantes orais antagonistas da vitamina K há, pelo menos, seis meses e entrevistados nas unidades de internação ou ambulatórios de três instituições públicas do interior do estado de São Paulo, no período de dezembro de 2013 a agosto de 2014. Participaram 50 indivíduos no estudo piloto e 500 na etapa de validação psicométrica do instrumento. A validação de construto foi verificada pela análise fatorial de informação plena e pela comparação da medida do conhecimento com variáveis associadas ao conhecimento da TAO (escolaridade e tempo de uso do medicamento). A consistência interna foi avaliada pelo teste de Kuder- Richardson (KR 20). O nível de significância adotado para os testes foi de 0,05. Resultados. Inicialmente o instrumento foi composto por 43 itens, entre eles itens de múltipla escolha e questões abertas. Após validação de face e conteúdo foram feitas modificações, dentre elas, a exclusão de questões abertas. A seguir realizado teste piloto, com a nova versão do instrumento denominada Avaliação do conhecimento em anticoagulação oral (IACACO), contendo 32 itens do tipo teste de múltipla escolha, dividido em dois módulos, o primeiro com 28 itens de conhecimentos gerais sobre a TAO (pontuação de 0 a 28) e o segundo, com 4 itens, específico para mulheres em idade fértil (pontuação de 0 a 4). A análise fatorial sugeriu um instrumento unidimensional. Ao avaliarmos o resultado da correlação entre as variáveis anos de estudo e conhecimento da TAO, constatamos correlação positiva e de forte intensidade entre as duas medidas (r = 0,61, p <=0,001). O valor da correlação entre as variáveis conhecimento e tempo de uso do ACO mostrou correlação positiva, mas de fraca intensidade (r = 0,21; p<= 0,001). O Coeficiente KR 20 de Kuder-Richardson foi de 0,86 para o módulo geral (28 itens) e para o instrumento com seus dois módulos (32 itens) foi de 0,85. Conclusão. As análises mostraram resultados favoráveis para o ICACO e trouxeram evidências de que o novo instrumento foi válido e confiável para avaliar o conhecimento dos pacientes em uso da TAO. Análises futuras da Teoria de Resposta ao Item poderão contribuir para a avaliação individual dos itens do IACACO. Não foi determinado ponto de corte para conhecimento suficiente ou não sobre a TAO, cabe ao profissional de saúde ou pesquisador determinar a melhor maneira de interpretar os resultados advindos da aplicação do instrumento. / Introduction. To evaluate the knowledge of individuals using oral anticoagulant therapy (OAT) is a strategy that health professionals can use to guide the care given to these people. The use of a valid and reliable psychometric instrument ensure a proper evaluation. Aim. To construct and validate an instrument to assess the knowledge of the OAT. Method. Methodological and cross-sectional study, which followed the following steps: preparation of items, face and content validation by a committee of judges, pilot study and application of the instrument in a sample of the population studied. The sample consisted of adult patients using oral anticoagulants antagonists vitamin K for at least six months and interviewed in unit cares for pacients and ambulatory clinics of three public institutions in the state of São Paulo, in December 2013 to August 2014. Attended 50 individuals in the pilot study and 500 in the psychometric validation of the instrument step. The construct validity was verified by factor analysis of full information and by comparing the measure of knowledge with variables associated with knowledge of the OAT. Internal consistency was estimated by Kuder- Richardson test (KR 20). The significance level for the tests was 0.05. Results. Initially, the instrument consisted of 43 items, including items of multiple choice and open questions. After validation of face and content changes were made, among them the exclusion of open questions. Following conducted pilot test with the new version of the called knowledge evaluation of oral anticoagulation instrument (KEOAI) containing 32 items of the type test of multiple choice, divided into two modules, the first with 28 items of general knowledge of the OAT ( score 0-28) and the second with 4 items, specific to women of childbearing age (score 0-4). Factor analysis suggested a one-dimensional instrument. When evaluating the results of the correlation between the variables years of study and knowledge of the OAT, we found a positive correlation and strong intensity between the two measurements (r = 0.61, p <=0,001). The value of the correlation between the variables knowledge and OAT usage time showed positive correlation, but low intensity (r = 0.21, p <= 0.001). The coefficient KR 20 Kuder- Richardson was 0.86 for the general module (28 items) and the instrument with its two modules (32 items) was 0.85. Conclusion. Analyses showed favorable results for KEOAI and brought evidence that the new instrument is valid and reliable for assessing the knowledge of patients using the OAT. Future analyzes of Item Response Theory can contribute to the evaluation of individual KEOAI items. It was determined cutoff point for sufficient knowledge or not on the OAT, it is up to the health professional or researcher to determine the best way to interpret the results from the application of the instrument.

Introdução. Avaliar o conhecimento, de indivíduos em uso da terapia com anticoagulantes orais (TAO), é uma estratégia que profissionais da saúde podem utilizar para orientar o cuidado dispensado a estas pessoas. O uso de um instrumento psicometricamente válido e confiável é fundamental para garantir uma avaliação adequada. Objetivo. Construir e validar um instrumento para avaliar o conhecimento sobre a TAO. Método. Estudo metodológico e de corte transversal, que seguiu as seguintes etapas: elaboração dos itens, validação de face e conteúdo por um comitê de juízes, estudo piloto e aplicação do instrumento em uma amostra da população estudada. A amostra foi constituída de pacientes adultos, em uso de anticoagulantes orais antagonistas da vitamina K há, pelo menos, seis meses e entrevistados nas unidades de internação ou ambulatórios de três instituições públicas do interior do estado de São Paulo, no período de dezembro de 2013 a agosto de 2014. Participaram 50 indivíduos no estudo piloto e 500 na etapa de validação psicométrica do instrumento. A validação de construto foi verificada pela análise fatorial de informação plena e pela comparação da medida do conhecimento com variáveis associadas ao conhecimento da TAO (escolaridade e tempo de uso do medicamento). A consistência interna foi avaliada pelo teste de Kuder- Richardson (KR 20). O nível de significância adotado para os testes foi de 0,05. Resultados. Inicialmente o instrumento foi composto por 43 itens, entre eles itens de múltipla escolha e questões abertas. Após validação de face e conteúdo foram feitas modificações, dentre elas, a exclusão de questões abertas. A seguir realizado teste piloto, com a nova versão do instrumento denominada Avaliação do conhecimento em anticoagulação oral (IACACO), contendo 32 itens do tipo teste de múltipla escolha, dividido em dois módulos, o primeiro com 28 itens de conhecimentos gerais sobre a TAO (pontuação de 0 a 28) e o segundo, com 4 itens, específico para mulheres em idade fértil (pontuação de 0 a 4). A análise fatorial sugeriu um instrumento unidimensional. Ao avaliarmos o resultado da correlação entre as variáveis anos de estudo e conhecimento da TAO, constatamos correlação positiva e de forte intensidade entre as duas medidas (r = 0,61, p <=0,001). O valor da correlação entre as variáveis conhecimento e tempo de uso do ACO mostrou correlação positiva, mas de fraca intensidade (r = 0,21; p<= 0,001). O Coeficiente KR 20 de Kuder-Richardson foi de 0,86 para o módulo geral (28 itens) e para o instrumento com seus dois módulos (32 itens) foi de 0,85. Conclusão. As análises mostraram resultados favoráveis para o ICACO e trouxeram evidências de que o novo instrumento foi válido e confiável para avaliar o conhecimento dos pacientes em uso da TAO. Análises futuras da Teoria de Resposta ao Item poderão contribuir para a avaliação individual dos itens do IACACO. Não foi determinado ponto de corte para conhecimento suficiente ou não sobre a TAO, cabe ao profissional de saúde ou pesquisador determinar a melhor maneira de interpretar os resultados advindos da aplicação do instrumento. / Introduction. To evaluate the knowledge of individuals using oral anticoagulant therapy (OAT) is a strategy that health professionals can use to guide the care given to these people. The use of a valid and reliable psychometric instrument ensure a proper evaluation. Aim. To construct and validate an instrument to assess the knowledge of the OAT. Method. Methodological and cross-sectional study, which followed the following steps: preparation of items, face and content validation by a committee of judges, pilot study and application of the instrument in a sample of the population studied. The sample consisted of adult patients using oral anticoagulants antagonists vitamin K for at least six months and interviewed in unit cares for pacients and ambulatory clinics of three public institutions in the state of São Paulo, in December 2013 to August 2014. Attended 50 individuals in the pilot study and 500 in the psychometric validation of the instrument step. The construct validity was verified by factor analysis of full information and by comparing the measure of knowledge with variables associated with knowledge of the OAT. Internal consistency was estimated by Kuder- Richardson test (KR 20). The significance level for the tests was 0.05. Results. Initially, the instrument consisted of 43 items, including items of multiple choice and open questions. After validation of face and content changes were made, among them the exclusion of open questions. Following conducted pilot test with the new version of the called knowledge evaluation of oral anticoagulation instrument (KEOAI) containing 32 items of the type test of multiple choice, divided into two modules, the first with 28 items of general knowledge of the OAT ( score 0-28) and the second with 4 items, specific to women of childbearing age (score 0-4). Factor analysis suggested a one-dimensional instrument. When evaluating the results of the correlation between the variables years of study and knowledge of the OAT, we found a positive correlation and strong intensity between the two measurements (r = 0.61, p <=0,001). The value of the correlation between the variables knowledge and OAT usage time showed positive correlation, but low intensity (r = 0.21, p <= 0.001). The coefficient KR 20 Kuder- Richardson was 0.86 for the general module (28 items) and the instrument with its two modules (32 items) was 0.85. Conclusion. Analyses showed favorable results for KEOAI and brought evidence that the new instrument is valid and reliable for assessing the knowledge of patients using the OAT. Future analyzes of Item Response Theory can contribute to the evaluation of individual KEOAI items. It was determined cutoff point for sufficient knowledge or not on the OAT, it is up to the health professional or researcher to determine the best way to interpret the results from the application of the instrument.

Abstract Background: Implantable cardioverter-defibrillator (ICD) surgery in patients with implanted left ventricular assist devices (LVAD) is associated with an increased risk of bleeding complications because of the need to ensure that these patients are adequately anticoagulated. Our study aimed to evaluate the safety of our new strategy of uninterrupted oral anticoagulation compared to heparin-bridging during the surgical interval. Methods: Between January 2009 and January 2020, 116 patients with LVAD underwent ICD surgery. Since January 2015, 60 patients were operated under continued sufficient oral anticoagulation with a vitamin k antagonist (VKA group). Fifty-six patients underwent a heparin-bridging regimen (heparin group). Demographics, perioperative data, complications, and mortality were analyzed. Results: Bleeding complications attributable to the surgical intervention occurred more often (19.6% vs. 10.0%, p = 0.142) and at a higher rate of re-exploratory surgery (14.3% vs. 5.0%, p = 0.088) in the heparin group without reaching statistical significance. Moreover, the heparin group patients' postoperative total length of stay was 10 days longer (17.8 ± 23.8 days vs. 8.3 ± 9.5 days, p = 0.007). There were no procedure-related deaths, no thromboembolic events, and no LVAD-related thrombosis. Conclusion: Our strategy of uninterrupted oral anticoagulation is safe and results in a reduction by more than half the number of days in hospital without an increase in adverse events.

This descriptive, correlational, cross-sectional study explored the relationships among the variables self-care action, self-care knowledge, and affiliated individuation and quality of life for persons on chronic warfarin therapy. This study also explored the moderating effects of self-care knowledge and affiliated individuation on quality of life. This research was guided by a theoretical framework based on modeling and role-modeling theory (Erickson, Tomlin, & Swain, 1983). The sample consisted of 83 adults between the ages of 30 to 91 years. The majority of participants were Caucasian, educated, retired and almost evenly distributed between male and female. Each subject completed the following instruments: the Oral Anticoagulation Knowledge (OAK) test, the Duke Anticoagulation Satisfaction Scale (DASS), the Basic Needs Satisfaction Inventory (BNSI), and the generic quality of life survey (SF36v2). Data was analyzed using correlation and hierarchical multiple regression analysis. Results indicated significant correlations among most of the study variables. Self-care action significantly explained variances in all but two quality of life variables. Self-care knowledge and affiliated individuation had statistically significant moderating effects on the DASS negative impact and hassles/burdens subscales. Self-care knowledge also demonstrated a significant moderating effect on the SF36v2 physical function subscale. These findings support the concepts proposed by the study's theoretical framework. This research serves as validation of Acton's (1997) study findings for the concept of affiliated individuation and its value as a self-care resource in a specific clinical population. / text