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EDITORIAL |
Saudi Arabia
In Asia, as in many parts of the world, a significant number of patients of various ages present with valvular heart disease requiring intervention. Considering the population of Asia, this number will be much greater than in the West. As the population is aging, the proportion with degenerative aortic and mitral valve disease is expected to rise. The prevalence of rheumatic fever remains high in many parts of Asia, ranging from 1.2 to 21 per 1,000, and many patients with valve disease are relatively young. Congenital cardiac defects are common, and these can involve the aortic and mitral valves. The result is patients with a very wide age range and spectrum of valvular heart disease, from the neonate and infant to the very old.
It is true that many valvular problems can be dealt with in the catheterization laboratory by cardiologists; nevertheless, surgery remains the main therapy at present. Many surgical options are available. The most appropriate procedure depends on multiple factors. There is no doubt that valve repair is superior if it can be accomplished successfully. The tricuspid valve is the most frequently repaired valve, the mitral valve is often repaired, whereas the aortic valve is repaired occasionally. When it comes to replacement, the dilemma starts. We have two basic entities: biological and mechanical valves. In balance is the problem of durability with biological valves and the need for anticoagulation with mechanical prostheses. There are published guidelines to help in decision-making.1 However, these guidelines are based on studies and observations mainly from the Western hemisphere where facilities are good, education is widespread, and the culture is fairly homogenous. So are the guidelines applicable in Asia where the facilities in many parts are scarce, education is lacking, and the culture is so diversified?
From our experience in dealing with valve patients in Saudi Arabia, we can say that it is very difficult to follow the guidelines. Anticoagulation control in particular is extremely problematic, and in our anticoagulation clinic, only 25% of patients fall within the target range of the international normalized ratio. In the past 20 years, and despite many concentrated efforts, this has changed only very little. Although it might be hard to believe, some of our patients from neighboring countries do not have access to warfarin. Other major drawbacks of permanent anticoagulation relate to exercise limitation in the young, and to females who wish to become pregnant. In such patients, no method of anticoagulation is risk-free.2 Warfarin administration is associated with an increased risk of fetal wastage and birth defects.3 Despite many recent publications advocating continued use of warfarin throughout pregnancy, and claiming that the risk of embryopathy and abortion are low (particularly if warfarin dose is 
5 mg per day), there is still a restrictive labeling recommendation against the use of warfarin during pregnancy.4 Keeping that in mind, and knowing that mechanical valves are not truly permanent as patients are not guaranteed reoperation-free survival, we opt in these situations to use biological valves. Bioprostheses are generally recommended for older age groups, and their durability in these patients has been well documented.5 In many situations, the biological valve actually outlives the patient. Use of bioprostheses in the young has been controversial, and their use below the age of 40 years is outside the guidelines. In our area, we have been implanting biological valves in young patients because of the difficulty encountered in controlling anticoagulation, and because of pregnancy in young females. Even with the need for multiple reoperations, the long-term survival of patients with biological valves is better than that of patients with mechanical valves. Several reports have suggested that pregnancy accelerates bioprosthesis degeneration, but other studies and also our own patient follow-up do not support this. After 18 years of follow-up, patients with biological cardiac valves did not demonstrate pregnancy-related accelerated degeneration.6 With a mean follow-up of 6 years in our patients < 40 years of age, who underwent mostly mitral valve replacement with the Hancock II porcine bioprosthesis, the actuarial freedom from structural valve degeneration, reoperation, and all events was 70.6% ± 5.2%, 66% ± 5.7%, and 60% ± 5.8% respectively. No valve was explanted for structural degeneration within 5 years. Why then do surgeons shy away from implanting bioprosthesis in the young? Probably the notion that reoperation constitutes a high risk. With experience, however, this turns out to be untrue; in many hands, operative mortality in the first redo reoperation is the same as in the initial operation. Our first redo mortality in patients with preserved left ventricular function is less than 1%. We would rather have patients come back for reoperation than not come back at all because they died of mechanical valve thrombosis or anticoagulation-related complications.
So coming back to the question, are the guidelines for everyone? The answer is NO, and one has to look at every patient individually and assess what is best for that particular person.
REFERENCES
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