Doppler features of occlusion of the internal thoracic artery due to preoperative branch embolization

Left Internal Thoracic Artery Graft Assessed By Means of Intraoperative Transesophageal Echocardiography

BACKGROUND

We report a method of intraoperative assessment of left internal thoracic artery (LITA) graft with transesophageal echocardiography regarding patency, stenosis, and presence of remnant branch artery.

METHODS

In 52 consecutive coronary artery bypass grafting surgery patients, blood flow velocity was measured at the origin of the LITA after coronary artery bypass grafting by means of transesophageal echocardiography. The flow pattern and velocity change at temporary clamping of the graft was examined and was compared with the postoperative angiographic findings.

RESULTS

The LITA was visualized in 47 of 52 cases (90.4%). The LITA flow was diastolic dominant, systolic dominant, or equivalent in 41, 3, and 3 cases, respectively. The anastomosis was stenotic in 2 of 6 cases of the latter two groups, but in none of the 41 cases with diastolic dominant flow (p = 0.0139). The branch artery was present in 4 of 6 cases of the latter two groups, but in only 2 of 41 cases with diastolic dominant flow (p = 0.0012). Remnant branch artery was found in all three cases with systolic dominant flow. The LITA flow was instantaneously reduced at clamping and recovered at declamping in every case with graft occlusion but one. The ratio of velocity change at clamping was less than 0.50 in all 41 cases without remnant branch, whereas it was more than 0.50 in 5 of 6 cases with a branch (p < 0.0001).

CONCLUSIONS

The transesophageal echocardiographic assessment with the clamp test is feasible intraoperatively in the majority of patients, enabling us to assess LITA graft patency, stenosis, or presence of a remnant branch.