Potential benefits of oral pentoxifylline before coronary artery bypass surgery

To the Editor,

We read with interest the recent publication by Mansourian et al. (1) published in Anatol J Cardiol 2014 Dec 31 entitled “Preoperative oral pentoxifylline in case of coronary artery bypass grafting with left ventricular dysfunction (ejection fraction equal to/less than 30%)” on effects of preoperative oral pentoxifylline in a cohort of high-risk patients undergoing coronary artery bypass surgery. They reported a shorter ventilation time and intensive care unit stay, less frequent need for blood product transfusion along with a significantly lower TNF-alpha and insignificantly lower interleukin (IL)-6 levels postoperatively in patients who received oral pentoxifylline. An increase in the level of inflammatory cytokines has been shown after cardiac surgery (2). It has been reported in both offpump and on-pump CABG (3). Some studies reported a diminished activation of the inflammatory system after off-pump procedures, but surprisingly, this has not been reported to have a clinically relevant benefit (2). Pentoxifylline is a xanthine derivative, and its main mechanism is decreasing blood viscosity. This drug has been shown to inhibit inflammatory cytokine release in both oral and intravenous forms (4).

The authors stated that they excluded patients with recent myocardial infarction, but the preoperative troponin-T levels are well above the normal range. The reason for the increased cardiac biomarkers is not clear. The levels of both TNF-alpha and IL-6 at the baseline are higher than the levels previously reported, which could be partially explained by the fact that the study is performed in a subgroup of high-risk patients with remarkable left ventricular dysfunction; however, the mean levels of the baseline TNF-alpha are approximately 10-fold higher than the baseline values of previous reports (2, 3). Also, the levels of both TNF-alpha and IL-6 show a decrease, though insignificant, following cardiopulmonary bypass, which has never been shown in previous studies that measured these levels immediately after surgery and later (2, 4). The explanation for this rather unexpected finding is not provided. The level of inflammatory cytokines is expected to rise when measured immediately after surgery and in subsequent time intervals, and the rise is expected to be lower in patients receiving pentoxifylline. In conclusion, though the paper aims to address the potential benefits of oral pentoxifylline in a high-risk subgroup of patients undergoing CABG, some clarifications needs to be made before drawing a conclusion.