Reply to Saha

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I want to thank Dr Saha for his kind remarks regarding our recent study [1, 2]. His observations are relevant, since there are varying philosophies regarding the configuration of the internal mammary arteries (IMAs) in coronary artery bypass graft surgery (CABG). Our study represents the experience of four different surgeons over 17 years (1994–10). In response to whether the IMAs were used ‘in situ’ or as a ‘Y’-graft, practitioners favoured different IMA configurations. Generally, the right IMA (RIMA) was used as an ‘in situ’ conduit when grafting the ramus intermedius or a very proximal obtuse marginal branch. When grafts were necessary in more distant territories off the left circumflex artery, the RIMA was either anastomosed to the ascending aorta (AA) or to the hood of a vein graft on the AA when the IMA was of small caliber. The majority of RIMAs were used to graft the circumflex territory. The ‘Y’-configuration represented a minority of cases in our series. In Table 5 of our study, the stroke rate for the off-pump left IMA (LIMA)-saphenous vein graft and bilateral IMA (BIMA) groups was 0%. We use a true no-touch technique of the aorta when the AA appears to harbour significant atherosclerotic disease by transesophageal echocardiography (TEE). Intraoperative TEE was in routine use at the beginning of our study. When significant disease was found on the AA, the RIMA was either anastomosed to the LIMA in a ‘Y’-type construct or anastomosed to the AA using a nonclamping occluder type of device. Propensity matching was performed using the pre-operative characteristics of both groups; no pre-screening for stroke was undertaken in the construction of the different cohorts. Several techniques can be used to avoid stroke, but none of them appears to be infallible [3]. As we all know, stroke is multifactorial and can rarely be attributable to one aetiology. The most successful approach appears to be careful preoperative screening of CABG patients, so that all the different sources of embolic disease can be evaluated and different intraoperative strategies can be utilized to prevent them. I read the technique described by Dr Saha et al. [4] of their in situ IMA graft construct, and it appears to be easy to implement. Nevertheless, a technique should be tailored to the surgeon performing the procedure, so he/she feels comfortable with it. I am not sure any particular strategy has been conclusively proven to be superior to another, as it is related to the experience the group has developed in that particular approach. Finally, I agree with Dr Taggart [5] that there exists robust published data debunking the old theory that the use of BIMA carries a higher rate of early mortality and/or significant morbidity. Obviously, clinical judgment must be exercised when deciding to use these conduits, particularly in such patients like the morbidly obese and poorly controlled diabetics. However, this cannot justify the low use of BIMA in USA (4%) and Europe (10%) [6]. The LIMA use became the standard of care through three decades of evidence-based research. I believe that we have reached a point where BIMA use should become a quality metric to assess the performances of different surgical units undertaking CABG.