Target INR for Patients with Rheumatic Heart Disease Taking Warfarin

Evidence-Based Recommendations

The American Heart Association recommends a target INR of 2.5 with a range of 2.0-3.0 for patients with rheumatic heart disease taking warfarin, regardless of whether atrial fibrillation is present, with a Class IIa level of evidence C indicating the weight of evidence is in favor of usefulness/efficacy 1, 2, 3
For patients with rheumatic mitral valve disease, long-term warfarin therapy with a target INR of 2.5 (range 2.0-3.0) is recommended by the American Heart Association/American Stroke Association 1, 3

The American College of Cardiology states that the safety and effectiveness of warfarin therapy depends critically on maintaining the INR within the therapeutic range of 2.0-3.0 4
The American College of Chest Physicians recommends that patients should aim for a time in therapeutic range (TTR) >65% to ensure optimal protection 5
More frequent INR monitoring is recommended when initiating therapy, then gradually reducing to every 4 weeks once stability is achieved, according to the American College of Cardiology 4

The American Heart Association recommends that antiplatelet agents should not be routinely added to warfarin therapy in patients with RHD to avoid additional bleeding risk 1, 3
For patients with RHD who have a recurrent embolism while receiving warfarin at therapeutic INR, adding low-dose aspirin (81 mg/day) may be indicated, as suggested by the American Heart Association 1, 3

The American College of Cardiology notes that the target INR for RHD (2.0-3.0) is lower than that recommended for mechanical prosthetic heart valves, which typically require an INR of 2.5-3.5 4

Subtherapeutic anticoagulation (INR <2.0) significantly increases the risk of thromboembolism and ischemic stroke, according to the American College of Cardiology 4
INR values >3.0 are associated with a greater incidence of major bleeding, especially intracranial hemorrhage when the INR rises above 3.5, as reported by the American College of Chest Physicians 5

The American College of Chest Physicians warns that targeting lower INR ranges (e.g., 1.5-2.0) is not supported by strong evidence and may lead to inadequate protection against thromboembolism 5
Inconsistent vitamin K intake through diet can cause fluctuations in INR values, making it important to maintain consistent dietary habits, as noted by the American Heart Association 6
Drug interactions can significantly alter warfarin metabolism and effect, requiring more frequent monitoring when starting or stopping other medications, according to the American College of Chest Physicians 5