In the UK, national guidance on the assessment of cardiac sounding chest pain (NICE CG95 2016) (1), advises that CT coronary angiography (CTCA) is the first line imaging modality. If this reveals coronary artery disease of uncertain functional significance or is non-diagnostic, non-invasive functional testing is advised as second line. Invasive coronary angiography (ICA) is only advocated as third-line when functional imaging is inconclusive or if intervention is planned and should not be performed merely to “check” CTCA. In addition, 45% of patients in SCOT-HEART...

This was a retrospective analysis of 281 consecutive CT coronary angiograms (CTCA) performed between July 2017 to June 2018 and October 2018 to January 2019. Data collected included basic demographic information, the degree of stenosis documented with a CAD-RADS score (Table 1), and the presence/absence of any subsequent functional imaging, invasive angiography, PCI, or CABG. It was also documented if the patient underwent invasive coronary angiography but no subsequent revascularisation was performed. Descriptive statistics wereused to analyse the results.

Out of 281 total scans,5 were non-diagnostic and 276 scans were suitable for analysis. Out of these, 231 (84%) were discharged without further investigation. A total of 24 patients out of 276 underwent subsequent functional imaging and25 underwent invasive coronary angiography; in 16 patients (64%) no revascularisation was performed. Downstream investigation rate per CAD-RADS score is shown inTable 2. As expected, the degree of downstream investigation and intervention increases as the degree of coronary artery stenosis increases.

The results show that overalladherence to the guidelines at our institution is good, with the majority of patients (84%) discharged without further investigation. In particular, very few patients with low CAD-RADS scores of 0, 1 or 2 had any subsequent functional imaging, suggesting thatthe results of CTCA are beingappropriately considered and very few invasiveangiograms are being performed when CTCA showsabsent oronlyminimal to mild coronary disease. Importantly, in 64% of patients undergoing invasive angiography no intervention was performed, suggesting that some of these may be unnecessary.

A. Amlani; London/UK - nothing to disclose S. M. Mak; London/UK - nothing to disclose G. Benedetti; London/UK - nothing to disclose R. Preston; London/UK - nothing to disclose

1. National Institute for Health and Care Excellence. Chest pain of recent onset: assessment and diagnosis. CG95. London: NICE, 2010. Available fromhttp://www.nice.org.uk/guidance/CG95 2.SCOT-HEART Investigators. "Coronary CT angiography and 5-year risk of myocardial infarction."New England Journal of Medicine379.10 (2018): 924-933. 3.Cury RC et al. CAD-RADS(TM) Coronary Artery Disease - Reporting and Data System. An expert consensus document of the Society of Cardiovascular Computed Tomography (SCCT), the American College of Radiology (ACR) and the North American Society for Cardiovascular Imaging (NASCI). Endorsed by the American College of...