In-Patient International Normalized Ratio Self-Testing Instruction After Mechanical Heart Valve Implantation

Jess L. Thompson, Thoralf M. Sundt, Maurice E. Sarano, Paula J. Santrach, Hartzell V. Schaff

Research output: Contribution to journalArticlepeer-review

10 Scopus citations


Background: Patient self-testing of the international normalized ratio (INR) has been shown to improve management of anticoagulation with warfarin and reduce risks of thromboembolism and bleeding. Self-testing instruction usually begins several weeks after hospital discharge. We evaluated the feasibility of in-hospital INR self-testing instruction in patients recovering from valve replacement. Methods: We instituted an education program on a self-testing device before hospital discharge in 50 adult patients (median age, 54 years; 66% men) undergoing cardiac valve replacement with mechanical prostheses. Patients were monitored for 1 month to assess their ability to self-test and the accuracy of the INR measurements. Results: Self-testing instruction began on postoperative day 4 (range, 1 to 8 days). Each patient had an average of 3.5 teaching sessions; each session lasted approximately 20 minutes. One month after discharge, all patients (98%) but 1 were able to self-test. No patient required interval instruction. One bleeding episode occurred in a patient whose INR exceeded the therapeutic range. Once warfarin doses were stabilized, 5 patients had subtherapeutic INR values on self-testing. The mean INR test result obtained from the coagulometer correlated well with values obtained by laboratory determination (r = 0.79). Conclusions: This evaluation of an in-hospital education program demonstrates that patients are able to learn INR self-testing and that most will continue to use the method without the need for interval instruction. Improved anticoagulation management by early introduction of INR self-testing should reduce thromboembolic and hemorrhagic complications after valve replacement.

Original languageEnglish (US)
Pages (from-to)2046-2050
Number of pages5
JournalAnnals of Thoracic Surgery
Issue number6
StatePublished - Jun 2008

ASJC Scopus subject areas

  • Surgery
  • Pulmonary and Respiratory Medicine
  • Cardiology and Cardiovascular Medicine


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