LIMA (Left internal mammary or thoracic ) is an unique artery , incidentally runs close to heart , has a privilege of supporting of human heart in its hour of crises ! . CABG surgery was started with saphenous grafts in 1967 . We have since moved on , from venous grafts to total arterial grafts . LIMA as a graft for coronary artery was a great innovation for cardiac surgery .Now , it can be stated ” CABG should not be done without a LIMA graft “
Advantages of LIMA
LIMA has good anatomical match for LAD. The 10 year patency rate is very favorable (60-80%) .LIMA is also a live graft enriched with nitric oxide , as it has native communication with subclavian artery .
Anatomy
The internal mammary artery originates from the under surface of the first portion of the subclavian, opposite the thyrocervical trunk. It descends behind the upper six ribs at a distance of about 1.25 cm. from the margin of the sternum, and at the level of the sixth intercostal space divides into the musculophrenic and superior epigastric arteries.
| The branches of the internal mammary are: |
|
| Pericardiacophrenic. |
|
Intercostal. |
| Anterior Mediastinal. |
|
Perforating. |
| Pericardial. |
|
Musculophrenic. |
| Sternal. |
|
Superior Epigastric. |
|
There are few Anatomical issues for LIMA
Subclavian -LIMA ostial stenosis : Rare
Looping of LIMA is rarely an issue in hemodynamic point of view. But some believe a looped up LIMA is slightly prone for graft disease.Complex looping are reported rarely.


A loop and a early branch of LIMA : What is the implication ?
Abnormal or premature branching pattern of LIMA needs clipping as it may divert blood supply to LAD.Terminal branches can be used as a sequential graft to a branch of LAD usually a diagonal. In spite of all these issues , LIMA is rarely unsuitable either anatomically or physiologically .It is a safest vessel to graft.
Future of LIMA graft assessment.
Currently selective LIMA angiogram is the gold standard.
MDCT (64 slice) gives stunning images of LIMA graft , but unfortunately , it has little value for functional assessment .
Functional assessment of LIMA graft By angiographic frame count is being attempted in our institute.Will be reported in 2012.
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