Second, West China Hospital, in Chengdu, has developed a national, multicenter database (Anticoagulation Therapy Database of Chinese Patients After Heart Valve Replacement, unpublished data, January 2011-December 2012) of patients who have undergone heart valve replacement since 2011. The database is part of the Low-intensity Anticoagulation Study. The database is now one of the largest of its kind in China, with 45 centers from 15 provinces participating in the project. To date, detailed information has been collected from >8,000 patients. The preliminary research demonstrates that when INR values are between 1.5 and 2.0, the incidence of both thromboembolic and bleeding complications is the lowest.