The knowledge that the RITA is biologically identical to the LITA is not new, and the logic behind using it, knowing the long term patency of LITA grafts is clear. The information presented by Dr. Tatoulis is impressive, but not new. Unfortunately it came too late. It has been my routine practice to use bilateral ITA for revascularization for two decades now, unless there was a good reason not to do so, including diabetic patients (among them my modest contribution to the FREEDOM trial). However, by using inferior conduits (vein grafts) and by performing incomplete revascularization on many occasions, we have left the ground open for our interventional-cardiology colleagues to claim that their drug eluting stents are at least as good as our vein grafts with their limited durability. We missed the opportunity to improve and augment the results of surgical revascularization over PCI. The world practice of myocardial revascularization has changed to such a degree that I am not sure we can still roll back the wheels of time.

Dr. Gardner discusses an outstanding paper presented from the STS meeting. It discusses the use of the RIMA being a virtually equivalent conduit as compared to the LIMA. I believe this is something that we have always known but have been unable to definitively state this until recently. It is my feeling that many interventional cardiologists do not feel the RIMA is as good a conduit option and we would be well served to make them aware of this landmark study. It is clear that use of both mammary arteries is the most superior option we have as conduits. I was surprised to hear that the RIMA behaved similarly as both a pedicled and a free graft. It has always been my feeling that these conduits would behave better as a pedicled graft. I have already modified my practice to become even more aggressive about the use of BIMAs in patients undergoing CABG even in those with advanced diabetes. It is my hope that our field will modify our general strategy so we are using this graft in at least 40% (if not more) of our multi vessel CABG cases.

This topic raises the concept of the ideal revascularization strategy. This study clearly demonstrates the superiority of BIMAs as the ideal conduits but what is the next best choice? This is currently not known and may never be known with certainty. My personal feeling is a drug eluting stent will be a superior option in select lesions, certainly compared to a saphenous vein or a radial artery. There are currently discussions of studies that may evaluate this hybrid strategy for coronary revascularization. There are already several sites performing pioneering work in this field and I look forward to seeing how it evolves. I suspect ultimately it will be a patient and lesion specific strategy but I hope we include surgical and interventional options in the same patient, not just an "all or none" strategy.

 

Dear Colleagues,

In the light of Loop and Lytle historical paper on IMA bypass patency  and even more importantly,that of Tector. (Fifteen years' experience with the internal thoracic artery, Ann Thorac Surg, 1986, 42: S22-S27) it is very much surprising, that the present US practice of RIMA utilization is about 5 %.

As a surgeon from Europe, Hungary I would like to report about a far higher employment of these two, unique vessels: in my country in centres doing around 800 CABG procedures annually, the LIMA usage is around 90 %, RIMA is 70% and BIMA is well above 45. Other composite grafts (using rGEA, radial artery) are also employed, in T, Pi, Y fashion- according to the standards of Calafiore. Apart from the convincing data of patency rate, there is another, fundamental feature of the IMA graft providing the physiological basis of its long term functionality,i.e.: its enhanced production of nitric oxide.

This special function has been extensively studied in vitro, but also in the operating theatre (Tarr FI, Sasvári M, Busman Cs, Rácz R: Evidence of nitric oxide produced by the internal mammary artery in the venous drainage of the recipient coronary artery.Ann Thorac Surg, 2005,Vol 80, pp 1728-1731), which proved, that these are in fact, DRUG ELUTING bypass conduits. Nitric oxide is a potent vasodilator and platelet adhesion inhibitor.

I am convinced, that based on this biochemical property of the IMAs, which surely forms the basis of long term patency altogether with its remodelling effect on the recipient coronary artery, arterial myocardial revascularization is SUPERIOR to PCI of any kind of DES.

The 3 year results of the SYNTAX trial clearly proves this remark. 

 

 

 

Mat,

 

One of the difficulties of using bilateral ITA's in patients with diabetes is an increase in sternal wound infections.  I have heard rates around 5% for diabetic patients with BITA, as opposed to less than 1% for LITA only.  Do these numbers seem correct to you?  Is there something specific that you do to try to reduce the sternal wound rate in patients with diabetes when using BITA as conduits?

As you know, Johanes Bonatti is using bilateral ITA's in diabetic patients using endoscopic harvesting and anastamosis with the DaVinci robotic.  With the caveat that long term data is pending, his short term results based on immediate angiography looks promising.  We have been choosing this option for patients with the grafts covering the more diffuse/ extensive lesions, and DES for the more discrete lesions.  

Anuj,

You are correct about the sternal wound complications being higher with BIMA particularly in diabetic patients.  Johannes' approach is certainly one way to address this but unfortunately there are very few people in the world that have his experience, expertise and resources to be able to do this procedure. He should be commended for all the work he has done.

In my practice I prefer BIMA but you need to make a patient specific decision.  In many diabetics it is probably worth the extra (and small) risk of a wound infection for the durability of both mammary arteries.  That being said there are some that I do not take this risk.  In particular poorly controlled diabetics that are very obese are a group that I shy away from BIMAs.  You also need to consider the target vessels.  Sometimes the disease may be so diffuse or smaller non-LAD targets and they may not be 'worthy' of a mammary artery and its associated increased risk.

I personally prefer BIMA but I still think in many cases a DES will beat a SVG , radial and especially a GEA. 

 

Mat