LETTERS TO THE EDITOR
Is There an Optimal Hematocrit Value for Cardiac Patients?
Tsung O. Cheng, MD, FACC*
* George Washington University, Medical Center, Washington, DC 20037 (Email: tcheng{at}mfa.gwu.edu).
The significance of anemia in congestive heart failure (CHF) has only recently received attention, as evidenced by two state-of-the-art papers published over the last several months (1,2). Anemia is more common in CHF than could be accounted for by age or the degree of renal dysfunction (2). Moderate to severe anemia can contribute to the development or worsening of CHF. Conversely, CHF can lead to moderate anemia (2). Recent reports have largely resolved the question: Is anemia a cause or a consequence of CHF? (3). Erythropoietin, which has a long history in the management of anemia complicating chronic renal failure, is being used for treatment of anemia in CHF (4–6).
Besides the potential risks of worsening hypertension and increased thrombosis as pointed out by Felker et al. (1), anemia correction in CHF may have other adverse effects. High hematocrit has been reported to be associated with a higher rate of Q-wave myocardial infarction (MI) after coronary artery bypass grafting (7). That a high hematocrit value was associated with an increased risk for MI has actually been known for a long time (8). As a matter of fact, George Burch (9–14), who wrote extensively on the subject since the early 1960s, advocated bloodletting in patients with coronary artery disease with a high hematocrit value (13,14). It might be appropriate to quote what Burch wrote in 1979 (14): "It is well known that a high hematocrit is associated with high viscosity and that a highly viscous fluid requires more work of the pump to circulate it than does a less viscous liquid. Furthermore, the flow of highly viscous fluid is reduced, even with all else being equal. Nevertheless, physicians fail to bleed patients with active coronary disease and myocardial ischemia, whose hematocrit is high and whose blood viscosity is increased. It has been shown that bloodletting in patients with ischemic heart disease definitely improved the clinical state of these patients when their hematocrit was reduced to average normal levels."
Therefore, as Felker et al. (1) cautioned, one must balance the risk of correcting the anemia in CHF against the risks of such treatment. What the optimal hematocrit value should be for patients with coronary artery disease or CHF has to await the results of controlled studies on a large number of patients.
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References
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1. Felker GM, Adams Jr KF, Gattis WA, O’Connor CM. Anemia as a risk factor and therapeutic target in heart failure J Am Coll Cardiol 2004;44:959-966.[Abstract/Free Full Text]
2. Coats AJS. Anaemia and heart failure Heart 2004;90:977-979.[Free Full Text]
3. Wisniacki N, Aimson P, Lye M. Is anemia a cause or a consequence of heart failure in the elderly? Heart 2001;85(Suppl I):P4.[CrossRef]
4. Silverberg DS, Wexler D, Blum M, et al. The use of subcutaneous erhythropoietin and intravenous iron for the treatment of the anemia of severe, resistant congestive heart failure improves cardiac and renal function and functional cardiac class, and markedly reduces hospitalizations J Am Coll Cardiol 2000;35:1737-1744.[Abstract/Free Full Text]
5. Silverberg DS, Wexler D, Sheps D, et al. The effect of correction of mild anemia in severe, resistant congestive heart failure using subcutaneous erythropoietin and intravenous irona randomized controlled study. J Am Coll Cardiol 2001;37:1775-1780.[Abstract/Free Full Text]
6. Mancini DM, Katz SD, LaManca J, Hudaihed A, Androne AS. Effect of erythropoietin on exercise capacity in patients with moderate to severe chronic heart failure Circulation 2003;107:294-299.[Abstract/Free Full Text]
7. Spiess BD, Ley C, Body SC, et al. Hematocrit value on intensive care unit entry influences the frequency of Q-wave myocardial infarction after coronary artery bypass grafting J Thorac Cardiovasc Surg 1998;116:460-467.[Abstract/Free Full Text]
8. Cheng TO. High hematocrit value is a risk factor for myocardial infarction J Thorac Cardiovasc Surg 1999;117:199-200.[Free Full Text]
9. Burch GE, DePasquale NP. Hematocrit, blood viscosity and myocardial infarction Am J Med 1962;32:161-163.[CrossRef][Web of Science]
10. Burch GE, DePasquale NP. The hematocrit in patients with myocardial infarction JAMA 1962;180:62-63.[Medline]
11. Burch GE, DePasquale NP. Hematocrit, viscosity and coronary blood flow Dis Chest 1965;48:225-232.[Web of Science][Medline]
12. Burch GE. Erythrocytosis and ischemic heart disease Am Heart J 1961;62:139-140.[Web of Science][Medline]
13. Burch GE, DePasquale NP. Phlebotomyuse in patients with erythrocytosis and ischemic heart disease. Arch Intern Med 1963;111:687-695.[Abstract/Free Full Text]
14. Burch GE. Of bloodletting Am Heart J 1979;98:666.[Medline]
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