High-Sensitivity Troponin I and Coronary Computed Tomography in Symptomatic Outpatients With Suspected CAD: Insights From the PROMISE Trial

Abstract

Objectives: The goal of this study was to examine associations between concentrations of high-sensitivity troponin I (hsTnI) (measured by using a single-molecule counting method) and obstructive coronary artery disease (CAD) in 1,844 stable, symptomatic outpatients with suspected CAD randomized to undergo coronary computed tomography angiography (CTA) in the PROMISE (Prospective Multicenter Imaging Study for Evaluation of Chest Pain) trial.

Background: Elevated concentrations of hsTnI are associated with CAD in patients with myocardial infarction. The meaning of hsTnI concentrations in stable symptomatic outpatients is not well understood.

Methods: Clinical characteristics and CTA results (including coronary artery calcium [CAC] scores) were expressed across hsTnI quartiles. Determinants of hsTnI concentration were identified. Multivariable logistic regression identified independent predictors of obstructive CAD50 (≥50% stenosis in any vessel) and CAD70 (≥70% stenosis or ≥50% left main).

Results: The median hsTnI concentration was 1.5 ng/l; nearly all (98.5%) subjects had measurable hsTnI, and 6.1% had concentrations ≥99th percentile concentration for this assay (6 ng/l). Higher CAC scores, as well as more prevalent and diffuse CAD, was seen in upper hsTnI quartiles (all p < 0.001). Independent predictors of hsTnI concentrations included age, sex, and CAC score (all p < 0.05). After adjusting for demographic and clinical characteristics, log-transformed hsTnI concentrations were associated with obstructive CAD50 (odds ratio: 1.15 per interquartile range; p = 0.02) and CAD70 (odds ratio: 1.25 per interquartile range; p = 0.001).

Conclusions: In stable symptomatic outpatients undergoing nonemergent coronary CTA for the diagnosis of suspected CAD, higher concentrations of hsTnI were associated with increasing presence and severity of coronary atherosclerosis. (Prospective Multicenter Imaging Study for Evaluation of Chest Pain [PROMISE]; NCT01174550).

Keywords: coronary artery disease; coronary computed tomography angiography; troponin.

Copyright © 2019 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Figures

Figure 1

A study flow for the present analysis. Following exclusions, 1844 subjects had available CT results and available blood samples for hsTnI testing.

Figure 2

Distribution of hsTnI in patients from PROMISE with available CT data. The median hsTnI concentration was 1.5 ng/L, with 6.1% above the 99th percentile for a healthy population (6 ng/L).

Figure 3

Predicted probabilities of A) coronary stenosis ≥50% in any vessel or B) coronary stenosis ≥70% in any vessel or left main coronary artery stenosis ≥50% as a function of hsTnI concentration. Probability for obstructive CAD is depicted as continuous log-transformed hsTnI concentration (red dots) as well as dichotomized around the 99th percentile concentration of 6 ng/L (blue dots). In both figures, the 99th percentile cut-off of 6 ng/L is identified by a dotted line.

Figure 3

Predicted probabilities of A) coronary stenosis ≥50% in any vessel or B) coronary stenosis ≥70% in any vessel or left main coronary artery stenosis ≥50% as a function of hsTnI concentration. Probability for obstructive CAD is depicted as continuous log-transformed hsTnI concentration (red dots) as well as dichotomized around the 99th percentile concentration of 6 ng/L (blue dots). In both figures, the 99th percentile cut-off of 6 ng/L is identified by a dotted line.