Intraluminal Projection of Descending Thoracic Aorta and Intraaortic Balloon Pump Catheter Examined by Transesophageal Echocardiography in Patients Undergoing Coronary Artery Bypass Surgery

The thoracic descending aorta (DTA) was examined in 57 patients undergoing coronary artery bypass grafting (41 men and 16 women: 63.0 ± 10.6 years old) using two-dimensional transesophageal echocardiography. An intraaortic balloon pump (IABP) was instituted in ten patients. A short-axis view of DTA was examined for intraluminal projection from the diaphragm level to the aortic arch level. In a frozen-frame image, the area and the height of the projection at each clockwise direction was measured. Four patients with preoperative insertion of an IABP catheter were excluded from the analysis. Seventy projections were found in 40 of 53 patients (75.5%), most frequently found at the 3 to 6 o'clock position. The tip of the IABP catheter was also located in the area between 3 and 6 o'clock of the aortic lumen in 6 of 10 patients. In one case, the area of projection was reduced from 1.1 cm2 to 0.7 cm2. In two of four patients with preoperative institution of an IABP catheter, projections were found near the catheter tip.　　

Both intraluminal projections and IABP catheter tip were most commonly located in the same region of the DTA, suggesting a possible dislodging of the projection while advancing the catheter. This was demonstrated in one case. The catheter tip may damage the aortic intima and/or cause a formation of abnormal projection. We conclude that intraoperative examination of DTA in addition to routine monitoring can provide useful information which is helpful for minimizing complications at the time of insertion of an IABP catheter.