This document discusses techniques for myocardial protection during redo cardiac surgery when a patent left internal mammary artery (LIMA) graft is present from a previous coronary artery bypass grafting (CABG) surgery. It presents two case reports of patients who underwent aortic valve replacement (AVR) plus additional bypass grafts while preserving the existing patent LIMA graft. For both cases, cardiopulmonary bypass was established and intermittent antegrade blood cardioplegia was used for myocardial protection while avoiding dissection and clamping of the LIMA graft. The document also reviews various literature describing alternative techniques for myocardial protection in such redo cases, including deep hypothermic circulatory arrest, retrograde cardioplegia, or temporary occlusion

1. MYOCARDIAL PROTECTION IN REDO
SURGERY WITH PATENT LEFT
INTERNAL MAMMARY ARTERY
By
Dr . Vijayanand palanisamy,
Dr . Anbarasu mohanraj

2. • A very high percentage of patients submitted to coronary
artery bypass grafting (CABG) develop symptomatic aortic
disease requiring surgery upon ageing.
• The widespread use of the LIMA and its high patency rate
have made it quite common to reoperate in the presence of
well-functioning coronary bypass grafts.

3. CASE REPORT
• CASE 1
Mr.Kathiresan 64 year old gentleman
k/c/o s/p cabg * 4 grafts (2002), Native LM with TVD ,Patent
LIMA ->LAD graft , occluded SVG->RAMUS , SVG ->Distal RCA ,
SVG->OM2 , Severe calcific AS , Mild AR , Mild MR , moderate
PAH , Moderately severe LVD (EF – 35%)
- Patient underwent REDO CABG * 2 GRAFTS (SVG->RAMUS ,
SVG ->PDA) + AVR using 19mm On-X VALVE

4. Operative details
Median sternotomy
Adhesions released and lima pedicle partial dissection done
carefully
CPB establised through aortic and DSSV cannulation
AXC and transverse aortotomy
Cold antegrade blood cardioplegia given through ostia
intermittently
Moderate hypothermia and systemic hyperkalemia
maintained

5. LIMA flow left undisturbed
LA vented
Native aortic valve excised and calcium removed carefully
Distal anastomosis done
While replacing aortic valve , due to excess return from Left
main coronary ostia , LIMA is clamped using soft bulldog for a
short interval
AVR done . LIMA clamp released . Aortotomy closed and
proximal anastomosis of vein grafts done onto aorta .
Came off CPB
CPB time : 141 min
AXC : 89 min

7. • CASE 2
Mr . Subramanian .M 63 year old gentleman k/c/o CCF , CAD
– native TVD , S/p CABG * 3 grafts LIMA -> LAD , SVG -> OM ,
SVG -> RCA-PDA (2011) , Severe calcific AS , Grade II AR , Mild
MR ,Severe LVD EF -33%
-Patient underwent AVR using 21 mm On-X valve

9. Operative details
Median sternotomy
Adhesions released and lima is not dissected
CPB establised through femoro-femoral bypass
AXC and oblique aortotomy
Cold antegrade blood cardioplegia given through coronary
ostia and venous graft ostia intermittently
Moderate hypothermia and systemic hyperkalemia
maintained

10. LA vented
Native aortic valve excised and calcium removed carefully
Aortic valve replaced and Aortotomy closed
Came off CPB
CPB time – 62min
AXC time – 30 min

11. REVIEW OF LITERATURE

12. Gillinov et al ;
• The traditional approach has been median sternotomy
followed by meticulous dissection and clamping of the IMA ,
however this procedure does carry a small but significant risk
of 5-6 % damage to the artery which can be disastrous
especially in the setting of calcified and poor quality native
coronary arteries

13. Gonçalo S. Paupério et al;
• Valve surgery was performed with non-dissection of the
internal thoracic artery graft, when patent, and antegrade
cardioplegic arrest of other territories
• Concomitant CABG was always performed prior to AVS, in an
empty beating or fibrillating heart, a technique described in
detail in a previous report by this group, which had also been
used in the original operation (1)
• If collateral backflow out of the left main ostium (from the
patent LITA) obscured the operative field during AVS, pump
flows were temporarily turned down for better visualization,
or the ostium was occluded by placing a cardioplegia cannula.

14. Savitt et al ;
• An alternative approach that avoids myocardial reperfusion
injury resulting from cardioplegic arrest is to perform beating
heart AVR with continued use of CPB, antegrade and/or
retrograde perfusion, and LIMA unclamped. In a series of 16
patients using this method, Savitt and colleagues reported a
mortality rate of 0%.
• One of the methods described has been cannulating the
coronary ostia and perfusing with oxygenated blood and
aortic valve replacement is done on a beating heart perfusing
any venous grafts if present intermittently.

15. Byrne et al ; and Lytle et al ;
- open IMA technique with deep hypothermia (20°C ) and aortic
cross
- -useful in minimally invasive surgery where IMA dissection can
be dangerous and time consuming.

16. Ravishankar Venkataraman et al ;
• alternative methods to avoid dissection of IMA and carry out
AVR by establishing deep hypothermia using axillary artery
cannulation, keeping a hyperkalaemic state and using
retrograde/antegrade cardioplegia for myocardial protection

17. Theodore Velissaris et al;
• The technique consists of preoperative insertion of a suitably sized
angioplasty balloon catheter into the proximal part of the graft
under fluoroscopic guidance. Intraoperative inflation of the balloon
results in occlusion of the graft during aortic cross-clamping .

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19. Thank U