Computed tomography coronary angiography: Diagnostic yield and downstream testing

The UK National Institute for Health and Care Excellence (NICE) updated its guidelines on stable chest pain in 2016 and recommended computed tomography coronary angiography (CTCA) as first line investigation for all patients with new onset symptoms. We implemented the guideline and audited downstream testing.

We undertook a retrospective search of the local radiology database from January 2017 to May 2018.

Six-hundred and fifty-two patients underwent CTCA (mean age of 55 years, 330 were male). Thirty-four patients were found to have severe coronary artery disease (CAD), with 30 undergoing invasive coronary angiography (ICA) which confirmed severe CAD in 22, a yield of 73%.Fifty-eight patients were found to have moderate CAD on CTCA with 36 referred for ICA, of which, 33 attended and 18 were found to have severe CAD. Eighteen were referred for imaging stress tests and one was positive. The total yield of severe CAD at ICA was 55%. The majority of patients had normal coronary arteries.

CTCA was an effective rule-out test for most patients. In patients that went on to have ICA, the overall yield of severe CAD was relatively high. This compares well with our previous audit applying the NICE 2010 guidelines which recommended ICA for all high probability patients wherein the yield of severe CAD was 30%.