Duplex ultrasound method to assess patency in the proximal part of the LIMA of Y-bypass grafts in late follow up related to multislice ct-scan after CABG.

The use of the left internal mammary artery (LIMA) as a bypass graft to
revascularize the left anterior descending artery (LAD) has improved the
durability of coronary artery bypass grafting.
To evaluate the long-term performance of the LIMA graft an accurate
non-invasive functional test without contrast of the LIMA graft is important.
Several methods have been described since the 1980*s to assess LIMA graft
patency. At present invasive angiography is the gold standard. However,
invasive angiography also has disadvantages i.e. the inability to quantify
severe vulnerable plaques, inadequate contrast filling especially into the
distal coronary artery parts and small side branches, catheter-induced spasm of
the LIMA, underestimation of eccentric plaques and overprojection of coronary
arteries. There are no validated non-invasive methods without contrast
available to control LIMA graft patency directly.

To assess whether the non-invasive duplex method can reliably determine
diameters and flow characteristics in the LIMA origin of LIMA-LAD versus
Y-bypass grafts late after CABG in relation to

-the number of distal anastomosis

-the adaptation to hyperaemic response

It is an observational, diagnostic and comparing investigation between
non-invasive duplex echocardiography and ct-scans.

1-Electrographic control -- 15 minutes
2-Read and sign the *informed consent* letter -- 10 minutes
3-Duplex at rest -- 20 minutes
4-Duplex in modified hyperemic response -- 10 minutes
5-Complete a short questionnaire --10 minutes
6-64-slice CT-scan control -- 30 minutes


Risk profile; very low