Incidental coronary artery calcification and cardiovascular risk stratification in the ICARUS registry

Abstract Background The presence and extent of coronary artery calcium (CAC) are associated with increased cardiovascular (CV) risk in asymptomatic individuals. However, the prognostic value of incidentally detected CAC in ungated thoracic computed tomography (uTCT) performed for other indications is unclear. Purpose To study the prognostic value, in terms of major adverse CV events (MACE), of the incidental detection and quantification of CAC in uTCT in routine clinical practice. Methods A retrospective sample of uTCT scans performed in January and February 2015 in our hospital was analysed. Baseline clinical characteristics, CV risk factors, CV risk scales, and pharmacological therapy were recorded. The presence and extent of CAC were visually assessed, and global CAC score was measured using the Agatston method on LIFEx-7.2.0 software. Patients were categorized according to Coronary Artery Calcium Data and Reporting System (CAC-DRS) categories. We analysed the time to first 3P-MACE, defined as CV death, non-fatal myocardial infarction or non-fatal stroke, whichever occurred first. A p-value 0.05 was considered statistically significant. Results The cohort comprised 256 patients (mean age 61.8±15.64 years, 57% male). Smoking habit (n=141, 55.1%), hypertension (n=123, 48%) and dyslipidemia (n=116, 45.3%) were the most prevalent CV risk factors, and median SCORE2 or SCORE2-OP was 7.3% 3.45%-15.3% risk at 10 years. During a median follow-up of 6.76 5-9.02 years, 28 (10.9%) patients experienced 3P-MACE (12 CV deaths, 5 non-fatal myocardial infarctions, and 11 non-fatal strokes). This subset was older (70.17±13.3 vs. 60.77±15.62 years, p=0.003), had increased prevalence of dyslipidemia (64.3 vs. 45.3%, p=0.03), hypertension (85.7 vs. 43.4%, p0.001) and previous CV disease (42.9 vs. 11.4%, p0.001), and showed higher fasting glucose levels (141.07±52.4 vs. 104.06±25.78mg/dL, p0.001) as a surrogate of diabetes mellitus. Median global CAC score was 1.15 0-232.64 Agatston units, and more than half of the cohort had at least mild CAC. Visual assessment detected mild, moderate and severe CAC in 96 (37.5%), 31 (12.1%), and 11 (4.3%) patients, respectively, while CAC-DRS categories by Agatston method showed an increased prevalence of severe CAC (n=58, 22.7%). On univariate analysis, global CAC score and CAC-DRS categories predicted 3P-MACE, although visual assessment provided superior risk stratification (χ² = 26.35 vs. 20.69, p0.05). However, on multivariate analysis only hypertension (HR 3.62 1.03-12.67, p=0.04), previous CV disease (HR 3.47 1.59-7.57, p=0.002), and fasting glucose levels (HR 1.02 1.01-1.03, p0.001) predicted 3P-MACE. Conclusion Quantification of incidentally detected CAC in uTCT by visual assessment and Agatston method can stratify long-term risk of 3P-MACE, although it may not be useful in patients with a previous history of CV disease.Incidental CAC detection in uTCT 3P-MACE risk stratification by CAC