Risk scores and coronary artery disease in patients with suspected acute coronary syndrome and intermediate cardiac troponin concentrations

Background: Guidelines recommend the use of risk scores to select patients for further investigation after myocardial infarction has been ruled out but their utility to identify those with coronary artery disease is uncertain.

Methods: In a prospective cohort study, patients with intermediate high-sensitivity cardiac troponin I concentrations (5 ng/L to sex-specific 99th percentile) in whom myocardial infarction was ruled out were enrolled and underwent coronary computed tomography angiography (CCTA) after hospital discharge. HEART, EDACS, GRACE, TIMI, SCORE2 and PCE risk scores were calculated and the odds ratio (OR) and diagnostic performance for obstructive coronary artery disease determined using established thresholds.

Results: In 167 patients enrolled (64±12 years, 28% female), 29.9% (50/167) had obstructive coronary artery disease. The odds of having obstructive disease was increased for all scores with the lowest and highest increase observed for an EDACS score ≥16 (OR 2.2 [1.1-4.6]) and a TIMI risk score ≥1 (OR 12.9 [3.0-56.0]), respectively. The positive predictive value (PPV) was low for all scores but was highest for a GRACE score >88 identifying 39% as high-risk for a PPV of 41.9% (30.4-54.2%). The negative predictive value (NPV) varied from 77.3% to 95.2% but was highest for a TIMI score of 0 identifying 26% as low-risk for a NPV of 95.2% (87.2-100%).

Conclusions: In patients with intermediate cardiac troponin concentrations in whom myocardial infarction has been excluded, clinical risk scores can help identify patients with and without coronary artery disease, although performance of established risk thresholds is suboptimal for utilisation in clinical practice.