Visual estimate of coronary artery calcium predicts prevalent coronary artery disease in patients with respiratory disease

Abstract

Abstract Background Coronary artery calcification (CAC) measured using ECG-triggered coronary computed tomography correlates strongly with overt cardiovascular disease risk. Evidence is emerging to suggest CAC measured on non-gated thoracic CT scans may also correlate with cardiovascular disease. Herein, we sought to ascertain the utility of Weston scoring (visual score for CAC) in predicting prevalent coronary artery disease (CAD) and incident cardiovascular disease (CVD) for patients undergoing lung cancer screening or follow-up for interstitial lung disease with a non-triggered high-resolution CT (HRCT) thorax. Methods The Computerised Radiology Information Service (CRIS) database was manually searched to determine all HRCT scans performed in a single UK trust from 01/05/2016 to 01/05/2017 for the aforementioned indications. Radiology reports and images of selected studies were reviewed. For patients with evidence of CAC, we calculated the calcium score using the Agatston and Weston methods. Clinical events were determined from the electronic medical record without knowledge of patients' CAC findings. At baseline, significant CAC was defined as Agatston >400 and Weston >7. Results 2152 scans were analysed. Data at follow up was available for 100% of patients, with a median duration of follow up of 3.6 years. A history of CAD was reported by 8% (172) of subjects at baseline, who were subsequently excluded from analysis. Significant CAC was found in 450 (22.5%) and 650 (32.5%) by Weston and Agatston scores respectively, with a significant correlation between the two scores (r-0.71, p<0.01). During follow up 7.4% (160) of patients developed incident CVD. Patients with low Weston scores of ≤7 and Agatston scores of ≤400 had a lower incidence of CVD compared to those with Weston >7 and Agatston >400 (31 [19.3%] vs 129 [80.6%]; P=0.003 for Weston scores; 37 [23.1%] vs 123 [76.9%] for Agatston scores; P<0.001). Conclusion In this retrospective study of patients with respiratory disease attending for HRCT scanning, the Weston visual score for CAC performs well in predicting prevalent CAD and future CVD events. With previous data demonstrating excellent inter- and intra- observer agreement, our study demonstrates Weston scoring is a valid tool in reporting non-gated CT scans, removing the need for dedicated software analysis as required with the Agatston score, and has a high overall positive and negative predictive value for future CVD. Further multi-centre prospective studies of this strategy, should be conducted to clarify the utility of Weston CAC scoring in non-gated CTs as a prediction tool which may be used to modify cardiac risk and reduce the risk of incident cardiovascular events. Funding Acknowledgement Type of funding sources: None.