Key result
Weekly warfarin dose strongly correlates with INR in ~67% of mechanical heart valve patients.
Why the study?
Although algorithms exist to predict individual warfarin doses, the relationship between the INR and cumulative warfarin dose remained to be determined in patients with mechanical heart valve replacement.
Observational (n=52)
No
There is a strong linear correlation between the INR and the cumulative weekly dosage of warfarin in most patients following mechanical heart valve replacement.
Answers are grounded in this paper and cite their sources.
May support INR-based warfarin adjustments in mechanical valves; leaves open prospective outcome validation.
Background Although several algorithms have been proposed to predict individual warfarin doses, the relationships between the international normalized ratio (INR) and cumulative warfarin dose remain to be determined. Objectives The aim of this study was to explore the correlation between the INR and the cumulative dosage of warfarin within a week in patients who have undergone mechanical heart valve replacement. Methods A retrospective study was conducted at the First Affiliated Hospital of Shantou University Medical College in southern China. Fifty‐two patients who underwent mechanical heart valve replacement between January 2016 and December 2022 were included. The daily warfarin dose, cumulative dosage of warfarin within a week, and INR value were recorded. A simple linear regression model was used to analyze the correlation between the INR and cumulative warfarin dosage within a week. Results Of the 52 patients who underwent mechanical heart valve replacement, 19 were male, and 33 were female. Twenty‐three and 18 patients had undergone mitral valve replacement and aortic valve replacement, respectively. Eleven patients underwent both mitral and aortic valve replacement. There was a strong linear correlation in 35 patients (67.31%), with a correlation coefficient (adjusted R 2 ≥ 0.7) identified between the INR and the cumulative dosage of warfarin within a week. The patients with weak correlations (adjusted R 2 < 0.7) were more likely to be female and have lower left ventricular ejection fractions, fewer days and lower cumulative warfarin doses at the first time of therapeutic INR. Multivariate logistic regression analysis revealed that none of these factors significantly affected the relationship between the INR and cumulative warfarin dose. Conclusion Our study revealed a strong linear correlation between the INR and the cumulative dosage of warfarin within a week in most patients with mechanical prosthetic heart valves.
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Cao et al. (2025) conducted an observational in Mechanical prosthetic heart valves (n=52). Warfarin was evaluated on Correlation between the INR and the cumulative dosage of warfarin within a week. A strong linear correlation (adjusted R2 ≥ 0.7) between the INR and the cumulative weekly dosage of warfarin was observed in 67.3% of patients with mechanical prosthetic heart valves.
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