E1517. Using the Abdominal Aorta Calcium Score to Predict Coronary Artery Disease
Cardiovascular disease is currently, and has been for some time now, the leading cause of death in America, comprising approximately 23.1% of all mortalities in 2017. Cardiac health screening in imaging is assessed through multiple modalities and tests. A current non-invasive method to assess the annual risk/probability of a cardiovascular event is through CT calcium scoring (Agatston scoring). With millions of CT exams being performed annually, the abdominal aorta and its atherosclerotic burden are frequently visualized. The purpose of this study is to assess the incidentally visualized abdominal aorta calcium score (AACS) and to prove a correlation to the coronary artery calcium score (CACS) and subsequent risk of coronary events.
Materials and Methods:
Using an institutional search engine, patients who had both a noncontrast CT of the abdomen and pelvis (NCCTAP) and a noncontrast coronary CT (NCCC) within 1 year of each other were queried. Exclusion criteria consisted of a prior history of CABG, coronary artery stenting, and aortic aneurysms or dissections. We analyzed 264 patients who met the criteria. Three radiology residents, who were trained in CT calcium scoring by a cardiothoracic radiology attending, scored the aorta and coronary arteries of the cohort. Each resident scored either the aorta or coronary arteries and were blinded to each other’s scores so as to not introduce bias. The Agatston calcium score scale was used to quantify the risk of coronary artery disease.
A total of 264 patients had their coronary arteries and aortas scored for analysis. The mean age for the 264 patients was 60.8 years (48% women, 52% men). The results showed a positive correlation (R = 0.49; p < .001) between a rising AACS and a rising CACS. Based on the trend in our data, a cutoff value was obtained to stratify risk based on a threshold score. This showed that in patients with an approximate AACS greater than 2500 (n = 62), 63.4% of patients had either severe (Agatson > 400) or extensive (> 1000) coronary disease. In comparison, only 9.3% of patients with an AACS less than 2500 (n = 202) had severe or extensive coronary disease.
Multiple studies have assessed the AACS and its correlation with future cardiovascular events through follow up; however, no study to our knowledge has used the AACS to predict coronary artery disease burden and hence, long-term risk. Our results show that a positive correlation exists between rising abdominal aorta and calcium scores. They also show a strong cutoff value where aortic scores above 2500 correlated to either a severe or extensive coronary Agatston score in most patients compared to those with scores below 2500. Being able to predict coronary artery disease based on incidentally noted aortic calcium scores may greatly help referring physicians and their patients by prompting further investigation (i.e., through coronary CT or cardiology referral), allowing for early detection.