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Real-time graft flow assessment using epigraftic ultrasonography during coronary artery bypass grafting.

OBJECTIVES
Real-time graft flow assessment in the operative field has been performed to ascertain the patency in coronary artery bypass grafting (CABG). This study aims to evaluate the efficacy of graft flow assessment by epigraftic ultrasonography.


METHODS
CABG was performed in 135 patients from January 2010 to December 2012. One hundred and ten patients (81.4%) underwent both real-time graft flow measurement using epigraftic ultrasonography and coronary angiography (CAG) with a total of 249 grafts. Parameters were obtained from flow velocity curves in all grafts. The grafts were divided into two groups: patent grafts (Group A) and failing grafts (Group B). All parameters were compared in these two groups. Logistic regression analysis was performed to detect the predictors of graft failure and receiver operating characteristic (ROC) curve analysis was used to calculate the optimal cut-off value of the predictors of graft failure.


RESULTS
The overall patency as measured by CAG of the grafts was 97.2% (242/249). Logistic regression analysis revealed that the percentage of systolic and diastolic reverse flow (%sRF, %dRF) as well as the pulsatility index (PI) were predictors of early postoperative graft failure. ROC curve analysis revealed that mean velocity <12.5 cm/s, %sRF >9.3%, %dRF >4.1% and PI >4.4 were predictors of early graft failure.


CONCLUSIONS
In this series, epigraftic ultrasonography depicted graft flow clearly. Epigraftic ultrasonography is a useful tool to predict graft failure during CABG. This technique is easily performed using a conventional linear ultrasound transducer.