The Importance of International Normalized Ratio Monitoring in Patients With Mechanical Pulmonary Valve Prosthesis

Background: The most challenging risk of mechanical valves is thromboembolic events; therefore, life-long anticoagulation therapy is necessary. Anticoagulation therapy should be adjusted for each patient with serial international normalized ratio (INR) monitoring. Due to the small number of patients with a mechanical valve in the pulmonary position, we are facing a lack of information about the therapeutic range of the INR in these patients. We aimed to evaluate patients with a history of pulmonary valve replacement (PVR) who faced malfunction and compare their INR and echocardiographic data at the time of malfunction and 3 months prior. Methods: In this cross-sectional study, 71 patients who had previously undergone PVR and presented to Shaheed Rajaie Cardiovascular Medical and Research Center with a diagnosis of pulmonary valve malfunction between 2014 and 2021 were included. Patients' INR and echocardiographic data at the time of the malfunction and 3 months before the malfunction diagnosis were gathered from the hospital's registry. IBM SPSS 20.0 was used for data analysis. Results: In this cross-sectional study, 71 patients with mechanical pulmonary valve malfunction were included. 49.3% (n = 35) were men, 50.7% (n=36) were women, and their mean age was 33.23 (±8.279). The mean INR of all patients 3 months before malfunction and at the time of malfunction was 2.29 (±0.753) and 2.20 (±0.704), respectively. Conclusion: In this study, most of our patients had an INR below the therapeutic range, both at the time of malfunction and 3 months prior. It emphasizes the importance of patient follow-up and keeping the INR in the therapeutic range.