Impact of computed tomography myocardial perfusion following computed tomography coronary angiography on downstream referral for invasive coronary angiography, revascularization and, outcome at 12 months.

Aims: The aim of this study was to assess the impact of adding stress computed tomography (CT) myocardial perfusion (CTP) to coronary CT angiography (CTA) on downstream referral for invasive coronary angiography (ICA), revascularization, and outcome in patients presenting with new-onset chest pain.

Methods And Results: Three hundred and eighty-four patients were referred for cardiac CT. Patients with lesions ≥50% stenosis underwent subsequently stress CTP. Perfusion scans were considered abnormal if a defect was observed in ≥ 1 segment. Downstream performance of ICA, revascularization, and the occurrence of major cardiovascular events (death, non-fatal myocardial infarction, and unstable angina requiring urgent revascularization) were assessed within 12 months. In total, 119 patients showed ≥50% stenosis on coronary CTA; stress CTP was normal in 61 patients, abnormal in 38 patients and was not performed in 20 patients. After normal stress CTP, 19 (31%) patients underwent ICA and 9 (15%) underwent revascularization. After abnormal stress CTP, 36 (95%) patients underwent ICA and 29 (76%) revascularizations were performed. Multivariable analyses showed a five-fold reduction in likelihood of proceeding to ICA when a normal stress CTP was added to a coronary CTA showing obstructive CAD. Major cardiovascular event rates at 12 months for patients with obstructive CAD and normal stress CTP (N = 61) were low: 1 myocardial infarction, 1 urgent revascularization, and 1 non-cardiac death.

Conclusion: The performance of stress CTP in patients with obstructive CAD at coronary CTA in the same setting is feasible and reduces the referral rate for ICA and revascularization. Secondly, the occurrence of major cardiovascular events at 12 months follow-up in patients with normal stress CTP is low.