Intraoperative graft assessment with transit-time flow measurement and epicardial ultrasound

Intraoperative bypass graft evaluation for coronary artery bypass graft surgery has now been recommended in three consecutive European guidelines for myocardial revascularization in 2010, 2014, and 2018. The two main modalities consist of transit-time flow measurement which assesses function of grafts and epicardial ultrasound to assess the anatomy of the anastomosis. Functional and morphological assessment are generally considered complementary, although transit-time flow measurement is the most commonly used. Transit-time flow measurement alone may have ambiguous values in 5–15% of grafts and this can lead to unnecessary graft revision. The addition of epicardial ultrasound aids interpretation of intraoperative graft assessment by allowing visualization of the anastomosis and correction of technical errors that, intuitively, will lead to improved patient outcomes.