Correspondence

Troponin T Levels and Acute Coronary Syndromes

N Engl J Med 2002; 347:1722-1723November 21, 2002

Article

To the Editor:

In their article regarding the use of troponin T levels as prognostic factors in patients with renal dysfunction, Aviles et al. (June 27 issue)1 conclude that these levels predict short-term prognosis “regardless of [the patient's] level of creatinine clearance.” This statement should be amended.

The current Kidney Disease Outcomes Quality Initiative defines chronic kidney disease by a glomerular filtration rate of less than 60 ml per minute — a definition that encompasses an estimated 7.6 million patients in the United States.2 An increasing proportion of these patients have a glomerular filtration rate of less than 30 ml per minute, for which care by a nephrologist and preparation for dialysis are recommended. Cardiovascular disease becomes increasingly prevalent as the glomerular filtration rate decreases; patients with end-stage renal disease have a rate of death from cardiovascular causes of 50 percent.3 In the study by Aviles et al., patients in the lowest quartile for creatinine clearance with a normal troponin T level (Table 2 of the article) still had a risk of death that was twice as high as that of patients in the highest quartile of creatinine clearance with an abnormal troponin T level. Thus, in a population with a high probability of cardiac events before testing, such as the population studied in the Global Use of Strategies to Open Occluded Coronary Arteries IV trial, a low glomerular filtration rate alone, independent of the troponin T level, should serve as an indication for aggressive treatment. On the other hand, in patients with a low glomerular filtration rate, a negative troponin T test cannot be used to predict a favorable prognosis. Troponin T measurements in this population therefore predict events well but are not useful for ruling out the possibility of death from cardiac causes in the short term.

Dirk M. Hentschel, M.D.
Massachusetts General Hospital, Boston, MA 02114
dhentschel@partners.org

3 References

1. 1

   Aviles RJ, Askari AT, Lindahl B, et al. Troponin T levels in patients with acute coronary syndromes, with or without renal dysfunction. N Engl J Med 2002;346:2047-2052
   Full Text | Web of Science | Medline

2. 2

   K/DOQI guidelines. New York: National Kidney Foundation, 2002. (Accessed October 30, 2002, at http://www.kidney.org/professionals/doqi/kdoqi/toc.htm.)
   

3. 3

   US Renal Data System. URDS 2001 annual data report: atlas of end-stage renal disease in the United States. Bethesda, Md.: National Institute of Diabetes and Digestive and Kidney Diseases, 2001. (Also available at http://www.usrds.org/adr_2001.htm.)
   

Author/Editor Response

The authors reply:

To the Editor: We agree with Dr. Hentschel that renal dysfunction is an independent predictor of poor short-term outcome among patients with suspected acute coronary syndromes, and indeed our data confirm that fact. Our concern regarding the prognostic value of troponin was not whether an elevated troponin level would predict a good prognosis in patients with renal dysfunction, but rather whether such an elevation would predict an even worse prognosis than would otherwise be the case.

Dr. Hentschel states that among patients with a suspected acute coronary syndrome, a low glomerular filtration rate alone should be an indication for aggressive treatment, since it predicts a poor outcome. Data from randomized trials clearly show that among patients with an elevated troponin level, aggressive treatment is likely to lead to a reduction in the rate of major clinical events.1,2 Similar evidence from randomized trials regarding the use of renal function alone to dictate the treatment strategy does not yet exist.

Ronnier J. Aviles, M.D.
Eric J. Topol, M.D.
Michael S. Lauer, M.D.
Cleveland Clinic Foundation, Cleveland, OH 44195
lauerm@ccf.org

2 References

1. 1

   Morrow DA, Cannon CP, Rifai N, et al. Ability of minor elevations of troponins I and T to predict benefit from an early invasive strategy in patients with unstable angina and non-ST elevation myocardial infarction: results from a randomized trial. JAMA 2001;286:2405-2412
   CrossRef | Web of Science | Medline

2. 2

   Hamm CW, Heeschen C, Goldmann B, et al. Benefit of abciximab in patients with refractory unstable angina in relation to serum troponin T levels. N Engl J Med 1999;340:1623-1629[Erratum, N Engl J Med 1999;341:548.]
   Full Text | Web of Science | Medline

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