Steal from Skeletonized Internal Thoracic Artery Graft during Hemodialysis after Coronary Artery Bypass Grafting

Background: We used transthoracic Doppler echocardiography to evaluate the potential for flow variation in a skeletonized internal thoracic artery (ITA) graftc ipsilateral to an upper-extremity arteriovenous fistula during postoperative hemodialysis. Methods: Between October 2008 and May 2009, 7 patients in chronic hemodialysis underwent coronary artery bypass grafting. We selected 5 of these patients according to the following inclusion criteria: patients who were undergoing chronic hemodialysis via a left upper-extremity arteriovenous fistula and in whom the skeletonized left ITA was anastomosed to the left anterior descending artery as an in situ graft; the right ITA was not used as a graft; postoperative multidetector computed tomography evaluation of the coronary artery demonstrated patency of the left ITA. The following parameters were calculated at baseline, after the dialysis pump was on, before the pump was turned off, and after the pump was off: peak systolic velocity, end-diastolic velocity, time-averaged mean velocity, pulsatility index, and ITA diameter. Flow was calculated with the following formula: Flow = Time-Averaged Mean Velocity x (Half the Diameter of the ITA)(2) x 60 x pi. Results: When the hemodialysis pump was started, there was a significant reduction in the flow of the left ITA (P = .01), whereas there was no variation in the flow of the right ITA (P = .54). During dialysis, no patients experienced hypotension, arrhythmia, or angina. Just after the end of dialysis, the left ITA flow significantly increased (P = .01). Conclusions: Flow reduction of the ITA graft ipsilateral to an upper-extremity arteriovenous fistula develops during postoperative hemodialysis, even when the skeletonization technique is used.