Per-vessel myocardial blood flow improvement after coronary artery bypass graft surgery quantified by CT myocardial perfusion imaging

BACKGROUND: While coronary artery bypass grafting (CABG) aims for complete angiographic revascularization, data on vessel-specific physiological recovery remains limited. We aimed to quantitatively assess region-specific changes in myocardial blood flow (MBF) before and after CABG using dynamic CT myocardial perfusion imaging (CT-MPI). METHODS: Twenty-six patients underwent coronary CT angiography (CCTA) and stress dynamic CT-MPI before and after CABG. Vessel-specific territories were segmented using a patient-specific minimum cost path algorithm. Myocardial territories were categorized by CABG status and baseline perfusion. RESULTS: >0.9 markedly increased (mean bias 29.23 ​± ​18.61%, p ​< ​0.00001) post-CABG. Perfusion improvement did not differ significantly across graft types. CONCLUSION: Our analyses suggest that postoperative perfusion improvement varies substantially between vessel territories and is primarily driven by the severity of baseline ischemia. Minimal improvement in territories without pre-existing hypoperfusion underscores the importance of per-vessel functional assessment to guide more effective revascularization strategies.