Background:
Current guidelines recommend vitamin K antagonist treatment with relatively higher international normalized ratio (INR) targets for patients with mechanical heart valve prostheses. However, there is lack of data from large clinical trials about the outcomes of low-intensity anticoagulant treatment in Chinese patients with mechanical heart valves.
Methods:
The Low-intensity Anticoagulation Therapy after Heart Valve Replacement is an ongoing multicenter, prospective, observational cohort study (ChiCTR-OCH-10001185). Between January 2011 and August 2013, qualified patients from 34 cardiac centers in China mainland were recruited in the Anticoagulation Therapy Database of Chinese Patients after Heart Valve Replacement. Baseline characteristics were collected and patients were followed up for anticoagulant treatment, INRs and adverse events till March 2014.
Results:
The database recruited 11,769 patients, and 11,040 patients (93.8%) undergoing mechanical heart valve replacement were analyzed in this study. The mean age was 48.9±11.5 years and 6,227 patients (56.4%) were female. A total of 9,870 patients (89.4%) of the baseline population completed at least 6 months follow-up. The median follow-up time was 1.2 years (range 0.5-2.2). For all 9,870 patients, 143,115 measurements of the INR were obtained. The average warfarin dosage was 2.98±1.16mg/d and the mean INR was 1.81±0.46, and 88.7% patients had an INR level≤2.5 during the follow-up period. The incidence of hemorrhagic events was the lowest in patients with an INR≤2.0, whereas the risk of thromboembolic complications in this group of patients was not significantly increased (Table 1).
Conclusions:
Low-intensity anticoagulation with an INR of 1.5 to 2.5 is safe and effective for Chinese patients with mechanical heart valves in short-term. The optimal INR targets for mechanical valve recipients with different implanting positions and risk factors require further investigation.