Development of severe string sign in internal thoracic arterial graft during first month.

In the present case, development of the string sign in an internal thoracic arterial graft was observed using transthoracic Doppler echocardiography. Following surgery, the diameter of the internal thoracic graft decreased; however, the diameter of the left anterior descending coronary artery did not change from 1.9 mm. Further, the flow velocity in the internal thoracic artery during the systolic phase became greater than that in the early phase and then decreased on postoperative day 19, and it was not detected on postoperative day 31. Coronary arteriography performed on postoperative day 31 revealed a severely stringed internal thoracic artery.