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Better anticoagulation control improves survival after valve replacement
Eric G Butchart1, Nicola Payne, Hui-Hua Li
1Department of Cardiothoracic Surgery, University Hospital of Wales, Cardiff, United Kingdom. egbutchart@aol.com
Insights
Poor anticoagulation control significantly reduces long-term survival after mechanical valve replacement. Optimizing international normalized ratio (INR) management is crucial for improving patient outcomes and longevity.
Area of Science:
- Cardiovascular Surgery
- Biomaterials Science
- Clinical Pharmacology
Background:
- Mechanical heart valves, such as the Medtronic Hall valve, require lifelong anticoagulation therapy.
- Maintaining therapeutic anticoagulation is challenging, with variability in international normalized ratio (INR) measurements being a common issue.
- The impact of anticoagulation control on long-term survival following Medtronic Hall valve replacement has not been fully elucidated.
Purpose of the Study:
- To assess the relationship between anticoagulation control variability and long-term survival after Medtronic Hall valve replacement.
- To identify predictors of reduced survival in patients with mechanical heart valves.
- To determine if improved anticoagulation management can enhance patient longevity.
Main Methods:
- Prospective collection of 82,297 INR measurements from 1476 patients undergoing single valve replacement with the Medtronic Hall valve (1979-1998).
- Exclusion of patients with early mortality or insufficient INR data, resulting in 10,203 patient-years of follow-up.
- Quantification of anticoagulation variability as the percentage of INR values outside the target range (2.0-4.0).
Main Results:
- Progressively increasing linearized late death rates with higher anticoagulation variability for both aortic and mitral valve replacements (P <.001).
- Significantly reduced 15-year survival rates with increasing anticoagulation variability for both aortic and mitral valve replacements (P <.001).
- Anticoagulation variability identified as the most significant independent predictor of reduced survival, surpassing factors like diabetes, age, and hypertension.
Conclusions:
- High anticoagulation variability is a critical independent predictor of decreased survival after mechanical valve replacement.
- Optimizing anticoagulation control, specifically minimizing INR variability, is essential for improving long-term patient survival.
- Achieving stable anticoagulation may lead to survival rates comparable to the general population for select patient groups.
Objective:
We sought to assess the effect of anticoagulation control on long-term survival after valve replacement with the Medtronic Hall valve (Medtronic, Inc, Minneapolis, Minn).
Methods:
Prospective follow-up data, including 82,297 international normalized ratios, were collected for 1476 patients undergoing single valve replacement with the Medtronic Hall valve between 1979 and 1994, with follow-up to the end of 1998. After excluding 204 patients who either died within 30 days or had fewer than 10 international normalized ratios recorded beyond 30 days, there were 10,203 patient years of follow-up for analysis. Anticoagulation variability was measured as the percentage of international normalized ratios outside a target range of 2.0 to 4.0 for each patient.
Results:
Linearized rates for late death rose progressively with increasing deciles of anticoagulation variability for both aortic and mitral valve replacement (2.7% and 3.3% per year, respectively, in deciles 1 and 2 up to 9.5% and 14.6% per year, respectively, in deciles 6-10; P <.001). Survival at 15 years after aortic valve replacement was 59% for low anticoagulation variability (deciles 1 and 2), 55% for intermediate anticoagulation variability (decile 3), and 28% for high anticoagulation variability (deciles 4-10); survivals at 15 years after mitral valve replacement were 56%, 42%, and 24%, respectively (P <.001 between low-intermediate anticoagulation variability and high anticoagulation variability for both aortic and mitral valve replacement). On multivariate analysis, significant predictors of reduced survival were anticoagulation variability per 20% increase (hazard ratio, 1.8), diabetes (hazard ratio, 1.6), decade of age (hazard ratio, 1.6), concomitant coronary artery bypass grafting (hazard ratio, 1.5), male sex (hazard ratio, 1.4), hypertension (hazard ratio, 1.4), New York Heart Association class III or IV (hazard ratio, 1.3), and non-sinus rhythm (hazard ratio, 1.2). Patients with low anticoagulation variability who were in sinus rhythm and did not have diabetes, coronary bypass grafting, or hypertension had survivals equal to those of the age- and sex-matched general population at 15 years. The incidence of valve-related deaths was significantly higher with high anticoagulation variability compared with the incidence with low-intermediate anticoagulation variability for both aortic (1.4% vs 0.5% per year, P <.001) and mitral valve replacement (1.5% vs 0.5% per year, P <.001). By means of univariate analysis, high anticoagulation variability was significantly associated with New York Heart Association class III or IV at 5 years postoperatively (P <.001) and with age of greater than 60 years at the time of the operation (P =.002).
Conclusions:
High anticoagulation variability is the most important independent predictor of reduced survival after valve replacement with a mechanical valve. Better anticoagulation control should improve survival.