Mean Platelet Volume Shows Distinct Patterns Between Mitral and Aortic Valve Replacement Patients but Does Not Predict Anticoagulation Quality in Mechanical Heart Valves

ABSTRACT: Mechanical heart valve replacement necessitates long-term warfarin anticoagulation to prevent thromboembolic complications, yet achieving adequate anticoagulation control remains challenging. This study evaluated whether mean platelet volume (MPV) could serve as a biomarker for anticoagulation quality in mechanical heart valve recipients. We conducted a retrospective longitudinal cohort analysis of 370 patients with mechanical heart valves receiving warfarin therapy. MPV and international normalized ratio (INR) were measured at 5 time points. Time in therapeutic range (TTR) was calculated using the Rosendaal method, with effective anticoagulation defined as TTR ≥60%. Correlations between MPV, INR, and TTR were analyzed overall and stratified by valve type. Only 34.1% of patients achieved effective TTR. Mean MPV was 10.31 ± 1.04 fL and mean INR was 2.79 ± 0.54. No significant correlation was identified between MPV and TTR. However, patients with mean INR ≤3.0 exhibited significantly higher MPV values than those with INR >3.0 (10.40 vs. 10.13 fL). Subgroup analysis revealed a significant inverse correlation between MPV and INR in patients with mitral valve replacement but not in patients with aortic valve replacement, with temporal variation across measurement periods. MPV showed poor discriminatory ability for predicting effective TTR. Multivariable regression identified atrial fibrillation, older age, higher platelet counts, and higher hemoglobin as independent predictors of effective TTR, while MPV showed no independent association. In conclusion, MPV does not serve as a reliable biomarker for anticoagulation quality in patients with mechanical heart valve. Enhanced anticoagulation management strategies are needed to improve TTR in this high-risk population.