Scripties UMCG - Rijksuniversiteit Groningen
 
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Prospective validation of a novel biomarker-based rule-out strategy for myocardial ischemia in patients suspected with stable coronary artery disease

(2017) Walter, J.E. (Joan)

BACKGROUND: The aim of this thesis was to prospectively advance a high-sensitivity cardiac troponin I (hs-cTnI) rule-out strategy for exercise-induced myocardial ischemia from bench to bedside by applying a three-step approach: validation in serum, correlation in plasma, and application on a clinical platform in plasma.
METHODS: Patients without known coronary artery disease (CAD) referred for rest/stress myocardial perfusion single photon emission tomography (MPI-SPECT) were assigned to three consecutive cohorts: validation, correlation, and application. Exercise-induced myocardial ischemia was adjudicated using expert interpretation of MPI-SPECT and coronary angiography. In the validation cohort hs-cTnI was measured with the research Erenna system in serum, in the correlation cohort with the research Erenna system in serum and plasma, and in the application cohort with the clinical Clarity system in plasma for the final clinical application.
RESULTS: Overall, myocardial ischemia was adjudicated in 21% (304/1478) of patients. In the validation cohort (n=613), hs-cTnI concentrations were significantly higher in patients with myocardial ischemia (median 2.79ng/L versus 1.94ng/L, P<0.001) as compared to patients without myocardial ischemia and allowed a rule-out with 95% sensitivity in 14% of patients. In the correlation cohort (n=606), hs-cTnI concentrations in serum and plasma strongly correlated (Spearman r=0.921) and had similar diagnostic accuracy as quantified by the area under the receiver operating characteristic curve (0.686 vs. 0.678, P=0.425). In the application cohort (n=555), very low hs-cTnI plasma concentrations (<0.47ng/L) ruled-out myocardial ischemia with 95% sensitivity in 10% of patients.
CONCLUSIONS: A single plasma hs-cTnI measurement can safely rule-out exercise-induced myocardial ischemia in around 10% of patients without known CAD.






 
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