A UK cardiac centre experience of low-risk, stable chest pain patients with calcium score of zero

The 2010 UK National Institute of Health and Care Excellence (NICE) guidelines for assessing patients with 'chest pain of recent onset' recommend coronary artery calcium scoring (CACS) to assess patients with a low risk of coronary artery disease (CAD) according to defined criteria. This study aims to evaluate the implementation of these guidelines in an area with a prevalence of CAD higher than the national average. Consecutive patients with recent onset stable chest pain were assessed by cardiologists in outpatient clinics at University Hospital Aintree, Liverpool, between January and December 2011. A total of 186 patients with a low risk of CAD underwent CACS and followon computed tomography coronary angiography (CTCA) if CACS ≤400. A CACS of zero was found in 94 patients and three of these were excluded due to motion artefacts. Of the remaining 91 patients, 75 (82.4%) had no visible atheroma, 10 (11%) had minor plaque, five (5.5%) had moderate disease and one (1.1%) had apparent severe disease, which was shown to be a false-positive result on subsequent invasive coronary angiography. This study shows a negative predictive value for severe disease of 99% for a CACS of 0 in stable patients with a low pre-test probability of CAD. This supports the NICE guidelines, with CACS being the investigation of choice in the UK to rule out significant CAD in selected patient populations. The fact that almost half of all the patients referred for CTCA had a CACS of zero makes this a good quick ruleout tool and, hence, avoids the need for follow-on CTCA.