Select a probe size with a nonconstrictive fit for the graft;
Use adequate amount of ultrasound couplant.
Avoid motion artifacts.
Occlude the Native Coronary Artery
A quick comparison of mean flow with and without occlusion of the native coronary
artery reveals the presence or absence of competitive flow. Occlusion of the native coronary artery creates optimal Flow-QC test conditions with maximal flow
through the graft and uncomplicated flow waveforms.
Assess Mean Flow to Confirm Graft Patency
Normal 30 ml/min (or higher) Mean Flow = Patent Graft
See Table, p. 21 of CABG handbook for a compilation from the scientific literature
of the “Normal Flow Range” for various coronary grafts.
Flow under 5 ml/min = Graft in Trouble
Look for kinks, twists in the graft, low MAP, vasospasm.
Redo anastomosis if indications point to technical error.
Apply Waveform Analysis to Graftswith Medium Range Flows between 5 - 30 ml/min
Does flow exhibit the expected pattern?
For left ventricle grafts: a diastolic dominant waveform.
For right-ventricle grafts: a systolic/diastolic balanced waveform.
Assess other factors that may account for a lowered flow:
