Monday, May 05, 2014


It was Dr Rene Favaloro of Argentina who performed the first coronary bypass graft at Cleveland Clinic, Ohio in May 1967. He used a reverse saphenous vein conduit to anastomose the proximal to the distal RCA in a 51 female/ She did well. Rene even had an angiogram done the next day, to show that the venous graft was patent. Another angio was performed on day 20. Well that was the advent of CABG in the treatment of coronary artery disease.
Well, since then a few good things have happened. Cardiac surgeons have got better and they have progressed to use arterial grafts, notably the left internal mammary to the LAD. It seemed very logical as arteries stand up to arterial pressures than veins when subjected to arterial pressures, and the left internal mammary artery is literally overlying the LAD. That is now the gold standard. The use of the left internal mammary artery as the prefered conduit for bypassing significant stenosis in the LAD. This is well supported by data from all the large cardiac surgical trials. Of course subjected to the fact that the left internal mammary artery is usable.
However, the second graft for triple vessel disease in now the subject of much debate. Should it be the right internal mammary, or the radial artery graft, or a saphenous vein graft?
At the ongoing American Association for Thoracic Surgery meeting at Toronto Canada, two papers were presented on this topic.
The first paper comes from the Harefield Hospital London. The lead author is Dr Shahzad Raja. Their team studied 1,526 patients who had CABG rom 2001 - 2013. These patients had multivessel disease with indications for CABG. All patients had LIMA to LAD. In addition, 747 patients had RIMA ( Right Internal Mammary Artery ) to another vessel and 779 had a right radial graft to another vessel.  Saphenous vein grafts were used should more grafts be necessary. After 30 days, there was no difference in post surgical complication, including wound dehiscence, strokes, mortality and renal complications. After 5-7 years follow up, there was a reduction in mortality in the patients who had bilateral internal mammary grafts. Those who had free radial artery grafts did not do as well.
The second paper comes from Melbourne Australia. The lead author is Dr Brain Buxton.
Dr Buxton and team studied 3774 patients with multivessel disease who had need for CABG, from 1995-2010. 2,998 patients received all arterial grafts ( meaning LIMA, RIMA and if necessary Radial artery grafts. 786 patients had LIMA + venous grafts. Of the 2,998 all arterial grafts, 97% had all arterial with some having free radial grafts and 36% had only bilateral internal mammary grafts. This group did the best. There was no difference in hospital mortality and morbidity. However, the 15 years mortality was the best in those with bilateral internal mammaries.

It must also be pointed out the bilateral internal mammaries require much patience and skill. Initially, when it was first being done, bilat mammaries, carried quite a high morbidity and mortality ( in hospital ) because of wound infection ( especially in diabetics ) and often resulted in septicemia and renal failure. Now the cardiac surgeons are better at harvesting the internal mammaries ( maybe the senior guy does it himself, instead of leaving to the junior MOs ) and wound infection is much less, no difference between single lima and bilat mammaries. Of course free radial grafts are so much more easy to harvest.

I suppose the message that I would like to convey is that since 1967 till now, cardiac surgery has advanced. It should be just a plumbing job. The choice of conduits matter. Find a cardiac surgeon who is prepared to be patient in harvesting both mammaries so that the patient can live longer and better. But if that cardiac surgeon is reluctant to do all arterial grafts, either stick with him and accept a compromised solution, or find a cardiac surgeon who will give you all arterial grafts.

Maybe we should also revive the Rene approach of having post CABG angiograms to see how patent our CABG grafts are? This maybe especially important with the advent of starters doing minimally invasive surgery, where grafts are stitched on with the heart beating. A 1 mm miss may translate to graft being placed wrongly. On a beating heart a 1 mm miss is not unlikely.

All arterial grafts is the State of the Art of CABG.

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