Factors Associated With Low TTR in Anticoagulation Management Following Prosthetic Heart Valve Replacement: A Retrospective Study

Background and Objective Time in therapeutic range (TTR), the proportion of time the international normalized ratio (INR) remains within the target range, assesses warfarin anticoagulation quality. Using the INR range of 1.5–2.5 recommended by the Chinese Guidelines for the Prevention and Treatment of Thrombotic Diseases , we explored factors associated with TTR < 60% during postoperative Days 7–90 after prosthetic valve replacement. Methods We retrospectively screened patients undergoing prosthetic valve replacement at Tianjin TEDA International Cardiovascular Hospital from August 2012 to July 2023. TTR was calculated by Rosendaal linear interpolation for INR 1.5–2.5; TTR < 60% indicated suboptimal control. Univariate and multivariable logistic regression identified associated factors. Entropy balancing with weighted logistic regression assessed the valve‐type association; bootstrap resampling ( n = 1000) evaluated internal stability and optimism‐corrected performance. Calibration and decision curve analysis (DCA) were assessed. Results Among 443 patients (306 bioprosthetic and 137 mechanical valve recipients), 153 (34.5%) had TTR < 60%. Age (OR = 1.021, 95% CI 1.001–1.042), log‐transformed B‐type natriuretic peptide (lnBNP; OR = 1.324, 95% CI 1.013–1.730), warfarin dose (OR = 1.409, 95% CI 1.138–1.744), red blood cell distribution width coefficient of variation (RDWCV; OR = 1.195, 95% CI 1.045–1.367), and amiodarone use (OR = 1.592, 95% CI 1.029–2.463) were independently associated with TTR < 60%. The model showed modest discrimination (C‐index = 0.655; bootstrap‐corrected C‐index = 0.630) and acceptable calibration (Hosmer–Lemeshow p = 0.599). DCA showed a positive net‐benefit pattern across threshold probabilities of 0.24–0.52. Subgroup analyses identified different association patterns by valve location. After entropy balancing, valve type was not independently associated with TTR < 60% (OR = 0.945, 95% CI 0.605–1.490; p = 0.807). Conclusions Age, BNP, RDWCV, warfarin dose, and amiodarone use were associated with suboptimal early postoperative anticoagulation control in Chinese patients after prosthetic valve replacement. These findings may help identify patients warranting closer monitoring, while valve‐location differences should be interpreted cautiously.