Patient knowledge of and adherence to oral anticoagulation therapy after mechanical heart-valve replacement for congenital or acquired valve defects

ObjectiveThis study sought to determine (1) the level of knowledge that mechanical heart-valve patients (because of congenital heart disease or acquired heart-valve defects) have about oral anticoagulation therapy; and (2) to what extent these patients adhere to this therapy.MethodsThis descriptive, cross-sectional study included 57 patients. Knowledge was measured using the Knowledge of Oral Anticoagulation Tool. Adherence was assessed with a visual analogue scale and the Swiss HIV Cohort Study Adherence Questionnaire.ResultsPatients poorly understood symptoms relevant to over-anticoagulation and the effects of alcohol and vitamins on oral anticoagulants. The knowledge level of patients with congenital heart disease and acquired heart-valve defects did not differ significantly. Three-quarters of patients claimed to be 100% adherent to oral anticoagulant therapy.ConclusionMost patients lack knowledge about oral anticoagulants, and one fourth of patients do not fully adhere to therapy.