CT measurement of changes in cerebral perfusion in patients with asymptomatic carotid artery stenosis undergoing carotid stenting prior to cardiac surgery: "proof of principle".

Aims: To identify asymptomatic patients with impaired cerebral perfusion using CT perfusion (CTP) technique during staged carotid stenting (CAS) and cardiac surgery. Methods and results: This is a prospective, non-randomised study in 16 neurologically asymptomatic patients designed to analyse cerebral perfusion using CTP before and after CAS. Mean transit time (MTT) was significant lower and cerebral blood flow (CBF) was significantly higher in the non-target hemisphere compared to the target hemisphere before treatment (4.64 +/- 1.08 s vs. 5.67 +/- 1.29 and 57.37 +/- 24.90s vs. 48.19 +/- 13.02, respectively). Mean dMTT (absolute difference in MTT values between treated and untreated hemisphere) decreased from 0.92 +/- 1.08s before to 0.04 +/- 0.30s after carotid revascularisation (p<0.05) and mean relative CBF (ratios of the treated to the untreated hemisphere) increased from 0.92 +/- 0.12 to 1.04 +/- 0.12 after revascularisation (p<0.05). Subgroup analysis based on pre-treatment dMTT showed significant changes in 50% of the patients with larger dMTT. There was one transient ischaemic attack reported 30 days after combined procedure. Conclusions: A significant improvement of cerebral perfusion after carotid stenting is shown in about 50% of the asymptomatic patients in this study. This suggests the potential presence of a compromised cerebral circulation in asymptomatic patients with severe carotid artery disease scheduled for cardiac surgery.