Ann Thorac Surg 2001;72:1527
© 2001 The Society of Thoracic Surgeons
Invited commentary
Eric G. Butchart, FRCSa
a Department of Cardiothoracic Surgery, University Hospital, Cardiff, Wales CF14 4XW, United Kingdom
This study confirms the findings of several other trials which have shown a benefit from self-managed anticoagulation in comparison to conventional management, in terms of a greater number of International Normalized Ratio (INR) values within the chosen target range. The importance of good quality anticoagulation control cannot be over-emphasised, as it has been shown that poor control, with a high percentage of INRs outside the target range, is a major independent risk factor for reduced long-term survival after valve replacement. Not only should self-managed anticoagulation facilitate this tighter control and thereby possibly enhance survival but patients should enjoy an improved quality of life with less reliance on hospital-based systems and greater freedom to travel.
Although there were more INR values in the target range and a greater estimated time within this range in the self-managed anticoagulation group, the authors were unable to demonstrate any associated reduction in thromboembolic and bleeding events in comparison to conventional anticoagulation, despite a higher ratio of aortics to mitrals in the self-managed group which should have favored this group. There may be several explanations for this:
- This was a small study with relatively short follow-up.
- Many events labelled as ‘thromboembolic’ in all valve series occur as the result of pathogenetic mechanisms not directly related to the prosthesis and uninfluenced by anticoagulation.
- The target INR ranges were lower than those recommended for prosthetic valves, particularly in the mitral position, and the thromboembolic rate was high in both groups, 13.4% per year in the self-managed group and 11.7% per year in the conventional management group.
- Data on adverse events were collected by postal questionnaire. This methodology is less accurate than direct patient interview and may overestimate the true number of thromboembolic events if ill-defined neurological symptoms are incorrectly ascribed to transient ischemic attacks (TIAs). A large number of "false" events in both groups could then blunt the discriminatory power of the comparison.
Further randomized trials of self-managed anticoagulation versus conventional management are required, beginning at the time of surgery and with larger numbers, longer follow-up, and more detailed stratification of patients according to their risk factors. Nevertheless, it is already apparent from this and other studies that there are many advantages of self-managed anticoagulation and it is likely that eventually this method of anticoagulation control will become almost as commonplace as the self-management of insulin dosage by diabetics.
Related Article
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Self-managed anticoagulation: results from a two-year prospective randomized trial with heart valve patients
- Pushpinder Sidhu and Hugh O. O’Kane
Ann. Thorac. Surg. 2001 72: 1523-1527.
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