Association Between Minor Elevations of Creatine Kinase-MB Level and Mortality in Patients With Acute Coronary Syndromes Without ST-Segment Elevation
- John H. Alexander, MD;
- Rodney A. Sparapani, BS;
- Kenneth W. Mahaffey, MD;
- Jaap W. Deckers, MD;
- L. Kristin Newby, MD;
- E. Magnus Ohman, MD;
- Ramòn Corbalàn, MD;
- Sergio L. Chierchia, MD;
- Jean B. Boland, MD;
- Maarten L. Simoons, MD;
- Robert M. Califf, MD;
- Eric J. Topol, MD;
- Robert A. Harrington, MD;
- for the PURSUIT Steering Committee
- Author Affiliations: Duke Clinical Research Institute, Durham, NC (Drs Alexander, Mahaffey, Newby, Ohman, Califf, and Harrington, and Mr Sparapani); Cardialysis, Rotterdam, the Netherlands (Drs Deckers and Simoons); Universidad Católica, Santiago, Chile (Dr Corbalán); Ospedale San Raffaele, Milan, Italy (Dr Chierchia); Hopital de la Citadelle, Liege, Belgium (Dr Boland); and the Cleveland Clinic Foundation, Cleveland, Ohio (Dr Topol). A list of the names of members of the PURSUIT Steering Committee has been published (N Engl J Med. 1998;338:436-443).
Abstract
Context Controversy surrounds the diagnostic and prognostic importance of slightly elevated cardiac markers in patients with acute coronary syndromes without ST-segment elevation.
Objectives To investigate the relationship between peak creatine kinase (CK)-MB level and outcome and to determine whether a threshold CK-MB level exists below which risk is not increased.
Design and Setting Retrospective observational analysis of data from the international Platelet Glycoprotein IIb/IIIa in Unstable Angina: Receptor Suppression Using Integrilin Therapy (PURSUIT) trial, conducted from November 1995 to January 1997.
Patients A total of 8250 patients with acute coronary sydromes without ST-segment elevation who had at least 1 CK-MB sample collected during their index hospitalization.
Main Outcome Measure Mortality at 30 days and 6 months, was assessed by category of index-hospitalization peak CK-MB level (0-1, >1-2, >2-3, >3-5, >5-10, or >10 times the upper limit of normal). Multivariable logistic regression was used to determine the independent prognostic significance of peak CK-MB level after adjustment for baseline predictors of 30-day and 6-month mortality.
Results Mortality at 30 days and 6 months increased from 1.8% and 4.0%, respectively, in patients with normal peak CK-MB levels, to 3.3% and 6.2% at peak CK-MB levels 1 to 2 times normal, to 5.1% and 7.5% at peak CK-MB levels 3 to 5 times normal, and to 8.3% and 11.0% at peak CK-MB levels greater than 10 times normal. Log-transformed peak CK-MB levels were predictive of adjusted 30-day and 6-month mortality (P<.001 for both).
Conclusions Our data show that elevation of CK-MB level is strongly related to mortality in patients with acute coronary syndromes without ST-segment elevation, and that the increased risk begins with CK-MB levels just above normal. In the appropriate clinical context, even minor CK-MB elevations should be considered indicative of myocardial infarction.
