Association between minor elevations of creatine kinase-MB level and mortality in patients with acute coronary
J H Alexander1, R A Sparapani, K W Mahaffey
1Duke Clinical Research Institute, Durham, NC 27715, USA. alexa017@mc.duke.edu
Insights
Even slightly elevated cardiac markers like creatine kinase-MB (CK-MB) indicate increased mortality risk in acute coronary syndromes. These findings suggest minor CK-MB elevations warrant consideration for myocardial infarction.
Area of Science:
- Cardiology
- Biomarkers
- Clinical Medicine
Background:
- Diagnostic and prognostic significance of mildly elevated cardiac markers in non-ST-elevation acute coronary syndromes (NSTE-ACS) is debated.
- Assessing the prognostic value of peak creatine kinase (CK)-MB levels is crucial for patient management.
Purpose of the Study:
- To examine the association between peak CK-MB levels and patient outcomes in NSTE-ACS.
- To identify if a specific CK-MB threshold exists below which mortality risk is not elevated.
Main Methods:
- Retrospective analysis of data from the international PURSUIT trial (November 1995-January 1997).
- Inclusion of 8250 patients with NSTE-ACS and available CK-MB measurements.
- Assessment of 30-day and 6-month mortality based on peak CK-MB levels categorized relative to the upper limit of normal.
- Multivariable logistic regression to determine independent prognostic significance of peak CK-MB.
Main Results:
- Mortality rates at 30 days and 6 months progressively increased with higher peak CK-MB levels.
- Patients with normal peak CK-MB had 1.8% (30-day) and 4.0% (6-month) mortality.
- Mortality rose to 8.3% (30-day) and 11.0% (6-month) for peak CK-MB levels >10 times the upper limit of normal.
- Log-transformed peak CK-MB levels were significant predictors of adjusted 30-day and 6-month mortality (P<.001).
Conclusions:
- Elevated CK-MB levels are strongly associated with mortality in NSTE-ACS patients.
- Increased mortality risk is evident even with CK-MB levels just above the normal range.
- Minor CK-MB elevations should be considered indicative of myocardial infarction within the appropriate clinical context.
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 syndromes 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.
Related Concept Videos
01:20Antiplatelet Drugs: Prostaglandin Synthesis, P2Y12 and Glycoprotein IIb/IIIa Inhibitors
Prostaglandin synthesis inhibitors, exemplified by the widely known aspirin, wield their power by irreversibly acetylating...
01:20Blood Studies for Cardiovascular System I: Cardiac Biomarkers
The essential diagnostic tools for detecting myocardial necrosis and monitoring individuals suspected of having acute coronary syndrome (ACS) include:
Troponins
Troponins, particularly cardiac troponins I and T, are the most precise and sensitive markers of myocardial injury. They are detectable within 4-6 hours of myocardial injury and remain...
01:30Acute Coronary Syndrome I: Introduction
01:19Acute Coronary Syndrome II: Pathophysiology and Clinical Manifestations
01:30Acute Coronary Syndrome III: Diagnostic Studies
01:28Acute Coronary Syndrome IV: Interprofessional Care