Development and Preliminary Clinical Validation of a High Sensitivity Assay for Cardiac Troponin Using a Capillary Flow (Single Molecule) Fluorescence Detector

Cardiovascular biomarkers: The state of the art in 2006

BACKGROUND

The explosion in cardiovascular biomarkers has been stimulated in large part by proteomics, genomics and an improved understanding of the pathophysiology of cardiovascular disease. New advances are occurring rapidly and remaining on the cutting edge of the science is harder and harder. In the past few years, major changes have evolved in our ability to use cardiac troponin, BNP and CRP which will markedly impact on their clinical utility. These changes including greater sensitivity, a better understanding of what specific fragments are being measured and how these markers are used clinically is obligatory. There is also a need for new markers.

CONCLUSIONS

As with other disciplines, this work has built on the work of others.

Long-Term Health Outcomes Associated with Detectable Troponin I Concentrations

Background: Recent data suggest that older men with detectable cardiac troponin I (cTnI) concentrations that remain below the 99th percentile concentration cutoff are at increased risk for subsequent cardiovascular events. We designed this study to extend this observation by examining risk prediction in both men and women presenting to an emergency department with chest discomfort.

Methods: We obtained data for all-cause mortality and hospital discharges associated with either acute myocardial infarction (AMI) or congestive heart failure (CHF) for up to 8 years after the initial presentation in 448 patients who originally presented in 1996 with acute coronary syndrome (ACS). We performed retrospective analysis for cTnI (AccuTnI™; Beckman Coulter) in frozen plasma samples based on the patients’ reported time from onset of symptoms. Peak cTnI concentration was used for risk assessment.

Results: Patients with cTnI concentrations ≥0.02 μg/L (i.e., limit of detection), including those whose peak values remained below the 99th percentile (0.04 μg/L), were at greater risk for death and AMI/CHF readmissions at 2, 5, and 8 years of follow-up compared with those with peak cTnI <0.02 μg/L. All results were statistically significant (P <0.05) except for death within 2 years among patients with normal but detectable cTnI (0.02 to 0.03 μg/L), relative to the group with values <0.02 μg/L. Kaplan–Meier analyses indicated that both men and women with cTnI ≥0.02 μg/L had worse outcomes (P <0.001).

Conclusion: Both men and women who present with possible ACS with detectable cTnI concentrations that remain below the 99th percentile are at a greater risk for future adverse events.