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

Heart Lung. 2011 Mar-Apr;40(2):139-46. doi: 10.1016/j.hrtlng.2009.11.005.


Objective: This 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.

Methods: This 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.

Results: Patients 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.

Conclusion: Most patients lack knowledge about oral anticoagulants, and one fourth of patients do not fully adhere to therapy.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Anticoagulants / administration & dosage
  • Anticoagulants / therapeutic use*
  • Belgium
  • Chi-Square Distribution
  • Cross-Sectional Studies
  • Female
  • Health Knowledge, Attitudes, Practice*
  • Health Status Indicators
  • Heart Defects, Congenital / nursing
  • Heart Defects, Congenital / surgery*
  • Heart Valve Prosthesis / adverse effects*
  • Humans
  • International Normalized Ratio
  • Male
  • Medication Adherence / statistics & numerical data*
  • Middle Aged
  • Pain Measurement
  • Postoperative Complications / drug therapy*
  • Surveys and Questionnaires
  • Young Adult


  • Anticoagulants