Improved Time in Therapeutic Range With Patient Self-Testing of Their INR Compared to Usual Care

Patients who receive a mechanical heart valve to replace a diseased heart valve must take an anticoagulation medicine the rest of their lives, and monitor their level of anticoagulation. Until recently, the testing of the level of anticoagulation was performed at medical laboratories or hospitals. The purpose of this study is to see if patients who test their level of anticoagulation by themselves at home and then call their doctor with the result have better control of their anticoagulation as compared to patients whose anticoagulation is checked only by their physician.