Duration after coronary artery bypass graft surgery and saphenous vein graft disease

We read the article with great interest by Kundi et al. (1), which was recently published online in Anatol J Cardiol 2015 May 5. The authors reported that the platelet-to-lymphocyte ratio (PLR) was found to be an independent predictor of saphenous vein graft disease (SVGD) in patients with stable angina pectoris. Kundi et al. (1) identified the significance of PLR in patients with stable angina after coronary artery bypass graft (CABG) surgery. This study has some major limitations, and the authors mention this situation in the text. However, there are no data about some other important predictors of SVGD. Because of some major flaws in the design of the study, we would like to provide a critique on the findings of the present article. It is well known that SVGD is not uncommon and increases with time (2). In the present study by Kundi et al. (1), there are no data about the time of performing CABG surgery. Time is one of the most important predictors of SVGD after CABG surgery. The incidence of SVGD is approximately less than 20% one year after CABG surgery (2, 3). However, after ten years of CABG surgery, only approximately half of the saphenous vein grafts are patent, and only a small proportion of patients are free from angiographic arteriosclerotic lesions (4, 5). In this sense, longer time after CABG surgery may be the reason of SVGD independently. Hence, to divide the study population as SVGD positive or negative and to indicate PLR as a predictor of SVGD, the duration after CABG surgery should be taken into consideration. The authors should state the duration after CABG surgery for each group and include it in the statistical analysis. In conclusion, PLR may play a role in saphenous vein graft failure. However, SVGD increases with time. To define a new predictor for SVGD, the duration after CABG surgery should be taken into consideration.