Role of transcutaneous ultrasound in evaluation of graft patency following minimally invasive coronary surgery.

OBJECTIVE Recent development in minimally invasive coronary surgery prompted us to carry out prospective evaluation of patients undergoing coronary artery bypass grafting through left anterior small thoracotomy. METHODS Between April 1996 and February 1997, 15 patients (age 32-70, 12 male) were operated on. The left internal thoracic artery (LITA) basal flow was assessed by means of transcutaneous Duplex ultrasound scanning with pulsed waved Doppler. Eight patients were studied in the immediate postoperative period (2-4 days) and seven patients (1-7 months) following revascularisation. In addition to that, nine patients underwent coronary angiography. RESULTS LITA graft flows were quantifiable in all 15 patients. In two patients there was a significant reduction in both time-averaged velocity and total flow. The subsequent coronary angiogram revealed severe (>50%) stenosis of LITA graft in both patients. One of these patients had a reversible obstruction documented by Duplex scanning and coronary angiography. Systolic measures did not differ between normal (13) and stenosed grafts (2), but diastolic time-averaged velocity (indicating coronary run-off) and total flow appeared lower in the latter. CONCLUSIONS LITA flow following left anterior small thoracotomy surgery can be evaluated non-invasively. Measurement of diastolic flow (i.e. coronary perfusion rather than internal thoracic branch run-off) and total flow is useful in estimating graft function.