- Email: [email protected]
Obesity and B-type natriuretic peptide levels in heart failure
Correspondence
JACC Vol. 45, No. 6, 2005 March 15, 2005:962–7
Obesity and B-Type Natriuretic Peptide Levels in Heart Failure The recent study by Mehra et al. (1) in the Journal contains the following sentence: “The severity of CHF was categorized by New York Heart Association (NYHA) functional class criteria, etc.” (1). It exemplifies a common practice in the current professional literature dealing with heart failure to use the NYHA functional classification as a system for grading the severity of heart failure. Such statements are not correct. The NYHA functional classification has never been proposed as a method for grading the severity of heart failure. This classification (2) is an imprecise, nonquantified exercise tolerance test in which the exercise is listed as “ordinary physical activity” (not further defined) and the end points are one or more of the following symptoms: undue fatigue, palpitation, shortness of breath, and anginal syndrome. Thus, patients with heart disease who are in class 1 are capable of performing “ordinary physical activity” without experiencing any of the listed symptoms; those in class 2 do experience one or more of the symptoms during “ordinary physical activity”; those in class 3 experience one or more of these symptoms when performing exercise that is less strenuous than “ordinary physical activity”; those in class 4 experience one or more of these symptoms at rest. The four-symptom end points listed above are common in patients with heart disease, but they are not specific for heart failure. They are not synonymous with heart failure, and in none of the official publications of the NYHA describing the functional classification in its present form, initially published in 1943 (3), are the words “heart failure” used. The functional classification provides a clinically useful, although crude, estimate of a patient’s exercise capacity. It is a conceptual and linguistic distortion to transform the simple exercise algorithm into the complex and multifaceted concept of heart failure.
cise but useful tool to assess exercise tolerance in patients with heart disease but that it was not intended for evaluating the severity of heart failure. However, time has stood witness to the importance of the NYHA functional class as a powerful discriminator of symptoms and prognosis in heart failure (1). As symptoms advance in heart failure, so does the gravity of prognosis. Because the NYHA functional classification system distinguishes severity of symptoms, it has been extrapolated in common parlance as a parameter to assess heart failure severity. To overcome this common misperception and largely because patients transit back and forth among various NYHA functional classes, Hunt et al. (2) have recently proposed a staging system for heart failure that incorporates the NYHA functional class as a symptom surrogate, the presence of which places the patient at a more advanced stage of disease. The need to establish reliable indicators of prognosis and accurate risk stratification parameters in heart failure is of paramount clinical importance. Various heart failure severity scores incorporate the NYHA system functional classification as an important variable (3). In our study (4), we were careful to not only assess the NYHA functional class but also to simultaneously include evaluations of echocardiographic findings, peak oxygen uptake by cardiopulmonary stress testing, and to measure cytokines related to severity of heart failure. Furthermore, owing to the poor interobserver variability of NYHA functional classification estimates, some have even gone a step further to propose newer functional classification systems that decrease the inherent variability of this measurement (5). Thus, we admit that the NYHA functional classification is a crude but practical and important measurement of symptom severity in heart failure. Shakespeare said it best in Hamlet: “There is nothing either good or bad, but thinking makes it so.”
*Martin Dolgin, MD
*Mandeep R. Mehra, MD, FACC Hector O. Ventura, MD, FACC
*Department of Medicine New York University School of Medicine 550 1st Avenue New York, NY 10016 E-mail: [email protected]
*Cardiology Ochsner Clinic Foundation 1514 Jefferson Highway New Orleans, LA 70121 E-mail: [email protected]
doi:10.1016/j.jacc.2004.12.029
REFERENCES 1. Mehra MR, Uber PA, Par MH, et al. Obesity and inappropriately suppressed B-type natriuretic peptide levels in heart failure. J Am Coll Cardiol 2004;43:1590 –5. 2. Dolgin M, editor. Nomenclature and Criteria for Diagnosis of Diseases of the Heart and Great Vessels. 9th ed. Boston, MA: Little, Brown, 1994:253– 4. 3. Criteria Committee of the New York Heart Association. Nomenclature and Criteria for Diagnosis of Diseases of the Heart. 4th ed. New York, NY: J.J. Little and Ives, 1943:71–3.
REPLY “Though this be madness, yet there is a method in’t.” William Shakespeare In principle, we agree with Dr. Dolgin that the New York Heart Association (NYHA) functional classification represents an impre-
967
doi:10.1016/j.jacc.2004.12.030
REFERENCES 1. Smith RF, Johnson G, Ziesche S, Bhat G, Blankenship K, Cohn JN. Functional capacity in heart failure. Comparison of methods for assessment and their relation to other indexes of heart failure. The V-HeFT VA Cooperative Studies Group. Circulation 1993;87 Suppl 6:VI88 –93. 2. Hunt SA, Baker DW, Chin MH, et al. ACC/AHA guidelines for the evaluation and management of chronic heart failure in the adult: executive summary. J Am Coll Cardiol 2001;38:2101–13. 3. Lund LH, Aaronson KD, Mancini DM. Predicting survival in ambulatory patients with severe heart failure on beta-blocker therapy. Am J Cardiol 2003;92:1350 – 4. 4. Mehra MR, Uber PA, Park MH, et al. Obesity and inappropriately suppressed B-type natriuretic peptide levels in heart failure. J Am Coll Cardiol 2004;43:1590 –5. 5. Kubo SH, Schulman S, Starling RC, Jessup M, Wentworth D, Burkhoff D. Development and validation of a patient questionnaire to determine New York Heart Association classification. J Card Fail 2004;10:228 –35.
JACC Vol. 45, No. 6, 2005 March 15, 2005:962–7
Obesity and B-Type Natriuretic Peptide Levels in Heart Failure The recent study by Mehra et al. (1) in the Journal contains the following sentence: “The severity of CHF was categorized by New York Heart Association (NYHA) functional class criteria, etc.” (1). It exemplifies a common practice in the current professional literature dealing with heart failure to use the NYHA functional classification as a system for grading the severity of heart failure. Such statements are not correct. The NYHA functional classification has never been proposed as a method for grading the severity of heart failure. This classification (2) is an imprecise, nonquantified exercise tolerance test in which the exercise is listed as “ordinary physical activity” (not further defined) and the end points are one or more of the following symptoms: undue fatigue, palpitation, shortness of breath, and anginal syndrome. Thus, patients with heart disease who are in class 1 are capable of performing “ordinary physical activity” without experiencing any of the listed symptoms; those in class 2 do experience one or more of the symptoms during “ordinary physical activity”; those in class 3 experience one or more of these symptoms when performing exercise that is less strenuous than “ordinary physical activity”; those in class 4 experience one or more of these symptoms at rest. The four-symptom end points listed above are common in patients with heart disease, but they are not specific for heart failure. They are not synonymous with heart failure, and in none of the official publications of the NYHA describing the functional classification in its present form, initially published in 1943 (3), are the words “heart failure” used. The functional classification provides a clinically useful, although crude, estimate of a patient’s exercise capacity. It is a conceptual and linguistic distortion to transform the simple exercise algorithm into the complex and multifaceted concept of heart failure.
cise but useful tool to assess exercise tolerance in patients with heart disease but that it was not intended for evaluating the severity of heart failure. However, time has stood witness to the importance of the NYHA functional class as a powerful discriminator of symptoms and prognosis in heart failure (1). As symptoms advance in heart failure, so does the gravity of prognosis. Because the NYHA functional classification system distinguishes severity of symptoms, it has been extrapolated in common parlance as a parameter to assess heart failure severity. To overcome this common misperception and largely because patients transit back and forth among various NYHA functional classes, Hunt et al. (2) have recently proposed a staging system for heart failure that incorporates the NYHA functional class as a symptom surrogate, the presence of which places the patient at a more advanced stage of disease. The need to establish reliable indicators of prognosis and accurate risk stratification parameters in heart failure is of paramount clinical importance. Various heart failure severity scores incorporate the NYHA system functional classification as an important variable (3). In our study (4), we were careful to not only assess the NYHA functional class but also to simultaneously include evaluations of echocardiographic findings, peak oxygen uptake by cardiopulmonary stress testing, and to measure cytokines related to severity of heart failure. Furthermore, owing to the poor interobserver variability of NYHA functional classification estimates, some have even gone a step further to propose newer functional classification systems that decrease the inherent variability of this measurement (5). Thus, we admit that the NYHA functional classification is a crude but practical and important measurement of symptom severity in heart failure. Shakespeare said it best in Hamlet: “There is nothing either good or bad, but thinking makes it so.”
*Martin Dolgin, MD
*Mandeep R. Mehra, MD, FACC Hector O. Ventura, MD, FACC
*Department of Medicine New York University School of Medicine 550 1st Avenue New York, NY 10016 E-mail: [email protected]
*Cardiology Ochsner Clinic Foundation 1514 Jefferson Highway New Orleans, LA 70121 E-mail: [email protected]
doi:10.1016/j.jacc.2004.12.029
REFERENCES 1. Mehra MR, Uber PA, Par MH, et al. Obesity and inappropriately suppressed B-type natriuretic peptide levels in heart failure. J Am Coll Cardiol 2004;43:1590 –5. 2. Dolgin M, editor. Nomenclature and Criteria for Diagnosis of Diseases of the Heart and Great Vessels. 9th ed. Boston, MA: Little, Brown, 1994:253– 4. 3. Criteria Committee of the New York Heart Association. Nomenclature and Criteria for Diagnosis of Diseases of the Heart. 4th ed. New York, NY: J.J. Little and Ives, 1943:71–3.
REPLY “Though this be madness, yet there is a method in’t.” William Shakespeare In principle, we agree with Dr. Dolgin that the New York Heart Association (NYHA) functional classification represents an impre-
967
doi:10.1016/j.jacc.2004.12.030
REFERENCES 1. Smith RF, Johnson G, Ziesche S, Bhat G, Blankenship K, Cohn JN. Functional capacity in heart failure. Comparison of methods for assessment and their relation to other indexes of heart failure. The V-HeFT VA Cooperative Studies Group. Circulation 1993;87 Suppl 6:VI88 –93. 2. Hunt SA, Baker DW, Chin MH, et al. ACC/AHA guidelines for the evaluation and management of chronic heart failure in the adult: executive summary. J Am Coll Cardiol 2001;38:2101–13. 3. Lund LH, Aaronson KD, Mancini DM. Predicting survival in ambulatory patients with severe heart failure on beta-blocker therapy. Am J Cardiol 2003;92:1350 – 4. 4. Mehra MR, Uber PA, Park MH, et al. Obesity and inappropriately suppressed B-type natriuretic peptide levels in heart failure. J Am Coll Cardiol 2004;43:1590 –5. 5. Kubo SH, Schulman S, Starling RC, Jessup M, Wentworth D, Burkhoff D. Development and validation of a patient questionnaire to determine New York Heart Association classification. J Card Fail 2004;10:228 –35.