Ability of myoglobin to predict mortality in patients admitted for exclusion of myocardial infarction

Kontos, Michael C.; Garg, Rajat; Anderson, F. Philip; Roberts, Charlotte S.; Ornato, Joseph P.; Tatum, James L.; Jesse, Robert L.

doi:10.1016/j.ajem.2007.01.002

« Previous Next »American Journal of Emergency Medicine
Volume 25, Issue 8 , Pages 873-879, October 2007

Ability of myoglobin to predict mortality in patients admitted for exclusion of myocardial infarction

Michael C. Kontos, MD
- Cardiology Division, Department of Internal Medicine, Virginia Commonwealth University, Richmond, VA 23298-0051, USA
- Department of Emergency Medicine, Virginia Commonwealth University, Richmond, VA 23298-0051, USA
- Department of Radiology, Virginia Commonwealth University, Richmond, VA 23298-0051, USA
- Corresponding author. Heart Station, North Hospital, PO Box 980051, Medical College of Virginia, Richmond, VA 23298-0051, USA. Tel.: +1 804 828 9989; fax: +1 804 828 3544.
Rajat Garg, MD
- Cardiology Division, Department of Internal Medicine, Virginia Commonwealth University, Richmond, VA 23298-0051, USA
F. Philip Anderson, PhD
- Clinical Chemistry Division, Department of Pathology, Virginia Commonwealth University, Richmond, VA 23298-0051, USA
Charlotte S. Roberts, MSN
- Cardiology Division, Department of Internal Medicine, Virginia Commonwealth University, Richmond, VA 23298-0051, USA
Joseph P. Ornato, MD
- Cardiology Division, Department of Internal Medicine, Virginia Commonwealth University, Richmond, VA 23298-0051, USA
- Department of Emergency Medicine, Virginia Commonwealth University, Richmond, VA 23298-0051, USA
James L. Tatum, MD
- Department of Radiology, Virginia Commonwealth University, Richmond, VA 23298-0051, USA
Robert L. Jesse, MD, PhD
- Cardiology Division, Department of Internal Medicine, Virginia Commonwealth University, Richmond, VA 23298-0051, USA

Received 15 September 2006; received in revised form 31 December 2006; accepted 1 January 2007.

Abstract

Background

Myoglobin can be used as an early marker to diagnose myocardial infarction (MI); and although nonspecific for myocardial necrosis, it seems to be a strong mortality predictor. Because myoglobin elevations are often present in patients with renal insufficiency, it is possible that the predictive value of myoglobin is secondary to identifying patients with renal insufficiency.

Methods

Consecutive patients admitted for MI exclusion without ST elevation on the initial electrocardiogram underwent serial assessment of cardiac markers (creatine kinase [CK], CK–myocardial band [MB], and troponin I [TnI]). Myoglobin was assessed at the time of admission and/or 3 hours later. Renal insufficiency was defined as a creatinine clearance <60 mL/min. Multivariate analysis was performed to identify predictors of 30-day and 1-year all-cause mortality.

Results

A total of 3461 patients were included in the analysis. Overall 30-day and 1-year mortality was 2.4% and 9.7%. Myoglobin was elevated in 675 (20%), CK-MB in 421 (12%), and TnI in 517 (15%). Among the 993 patients with renal insufficiency, myoglobin was elevated in 43%, CK-MB in 17%, and TnI in 21%. Independent predictors of 30-day and 1-year mortality were similar and included age ≥65 years, prior MI, and an ischemic electrocardiogram, whereas myoglobin was the strongest multivariate predictor (odds ratio [OR] 2.8, 95% confidence interval [CI] 2.1-3.7), including those with renal insufficiency (OR 2.3, 95% CI 1.6-3.4). Troponin I had borderline predictive value (P = .08, OR 1.4, 95% CI 0.96-2.0), whereas CK-MB was not predictive in either group.