Objectives The aim of this study was to determine if patients presenting with symptoms of acute coronary syndrome and foud to have mild (25% to 50%) diameter reduction with computed tomographic angiography (CCTA) are likely to benefit from further diagnostic testing.

Methods A registry study of 215 subjects with symptoms concerning for possible acute coronary syndrome with low-risk features found to have mild maximal diameter stenosis on CCTA was performed at our hospital. The potential contribution of additional testing was determined by measuring the major adverse cardiac events (MACE) from presentation through 30 days. The MACE included myocardial infarction, coronary revascularisation, unstable angina, and cardiovascular death.

Results The MACE occurred in 1 (0.5%) of 215 subjects (95% confidence interval, 0%-2.6%) and was identified by an elevation of serial cardiac markers during the index hospitalisation. No patients experienced cardiovascular death or required revascularisation.

Conclusions In patients with emergent low-risk chest pain and 25% to 50% diameter coronary stenosis by CCTA, the rate of near-term MACE is very low. Serial cardiac markers may be beneficial in this subgroup. Routine provocative testing is unlikely to be beneficial during the index visit.