ABSTRACT
BACKGROUND: We determined whether high-sensitivity cardiac troponin I can improve the estimation of the pretest probability for obstructive coronary artery disease (CAD) in patients with suspected stable angina. METHODS AND RESULTS: In a prespecified substudy of the SCOT-HEART trial (Scottish Computed Tomography of the Heart), plasma cardiac troponin was measured using a high-sensitivity single-molecule counting assay in 943 adults with suspected stable angina who had undergone coronary computed tomographic angiography. Rates of obstructive CAD were compared with the pretest probability determined by the CAD Consortium risk model with and without cardiac troponin concentrations. External validation was undertaken in an independent study population from Denmark comprising 487 patients with suspected stable angina. Higher cardiac troponin concentrations were associated with obstructive CAD with a 5-fold increase across quintiles (9%-48%; P<0.001) independent of known cardiovascular risk factors (odds ratio, 1.35; 95% confidence interval, 1.25-1.46 per doubling of troponin). Cardiac troponin concentrations improved the discrimination and calibration of the CAD Consortium model for identifying obstructive CAD (C statistic, 0.788-0.800; P=0.004; χ2=16.8 [P=0.032] to 14.3 [P=0.074]). The updated model also improved classification of the American College of Cardiology/American Heart Association pretest probability risk categories (net reclassification improvement, 0.062; 95% confidence interval, 0.035-0.089). The revised model achieved similar improvements in discrimination and calibration when applied in the external validation cohort. CONCLUSIONS: High-sensitivity cardiac troponin I concentration is an independent predictor of obstructive CAD in patients with suspected stable angina. Use of this test may improve the selection of patients for further investigation and treatment. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov. Unique identifier: NCT01149590.
Subject(s)
Angina, Stable/diagnosis , Coronary Artery Disease/diagnosis , Coronary Stenosis/diagnosis , Troponin I/blood , Adult , Angina, Stable/blood , Angina, Stable/diagnostic imaging , Angina, Stable/therapy , Biomarkers/blood , Clinical Decision-Making , Computed Tomography Angiography , Coronary Angiography/methods , Coronary Artery Disease/blood , Coronary Artery Disease/diagnostic imaging , Coronary Artery Disease/therapy , Coronary Stenosis/blood , Coronary Stenosis/diagnostic imaging , Coronary Stenosis/therapy , Denmark , Female , Humans , Male , Middle Aged , Multidetector Computed Tomography , Predictive Value of Tests , Prognosis , Randomized Controlled Trials as Topic , Reproducibility of Results , Risk Factors , Scotland , Severity of Illness IndexABSTRACT
BACKGROUND AND AIMS: Typical angina pectoris (AP) and high-sensitive troponin I (hs-TnI) are independently associated with coronary artery disease (CAD) and future cardiovascular events (CVE). This study aimed to assess the individual and combined diagnostic and prognostic impact of symptoms and hs-TnI in stable chest pain patients without prior cardiovascular disease. METHODS: During a one-year period, 487 patients with suspected stable AP underwent invasive or CT-coronary angiography (significant stenosis ≥50%). At study inclusion, a careful symptom evaluation was obtained, and patients were classified as having typical AP, atypical AP, or non-cardiac chest pain. Hs-TnI was measured in all patients and divided into tertiles for analysis. Follow-up was a median of 4.9 years with cardiovascular death, non-fatal myocardial infarction, unstable AP, ischemic stroke, coronary-artery-bypass-grafting, percutaneous coronary intervention, and peripheral vascular surgery as combined endpoint. RESULTS: Hs-TnI was detected in 486 patients (99.8%). By multivariate regression analysis, typical AP and hs-TnI elevation were associated with increased risk of having significant CAD (typical AP, OR: 3.46; 95% CI: 2.07-5.79; p < 0.0001, hs-TnI, OR: 1.50; 95% CI: 1.12-2.01; p = 0.007) and experiencing future CVE (typical AP, HR: 2.64; 95% CI: 1.74-3.99; p = 0.001, hs-TnI, HR: 1.26; 95% CI: 1.06-1.49; p = 0.008). Patients in the lowest hs-TnI tertile, without typical AP (n = 107) had a 1.9% absolute risk of significant CAD and a 3.7% absolute risk of long-term CVE. CONCLUSIONS: In clinical stable patients without known cardiovascular disease, a thorough chest-pain history in combination with hs-TnI testing can identify a significant low-risk group. The prognostic need for coronary angiography in these patients seems limited.
