NONINVASIVE ASSESSMENT OF LEFT INTERNAL MAMMARY ARTERY GRAFT PATENCY USING DUPLEX-DOPPLER ECHOCARDIOGRAPHY FROM SUPRACLAVICULAR FOSSA

Objectives. The purpose of this study was to clarify the usefulness of duplex Doppler echocardiography from the supra clavicular fossa for assessment of left internal mammary artery graft patency. Background. A noninvasive method to assess coronary artery bypass graft patency would be useful for clinical diagnosis and long-term follow-up of graft outcome. Methods. Duplex Doppler echocardiography from the supraclavicular fossa was performed in 56 consecutive patients who underwent postoperative cardiac catheterization studies, including quantitative angiography. All patients underwent coronary artery bypass graft surgery using the left internal mammary artery graft to the left anterior descending coronary artery. Results. The left internal mammary artery graft and its Bow were detected in 55 (98%) of the 56 patients with duplex Doppler echocardiography from the supraclavicular fossa. According to the quantitative angiographic data, the patients were assigned to three groups: group A (36 patients) with a normal left internal mammary artery graft (< 50% diameter stenosis), group B (9 patients) with intermediate (50% to 75% diameter) graft stenosis and group C (10 patients) with severe (> 75% diameter) graft stenosis. The diastolic/systolic peak velocity ratio was smaller in group C than in groups A and B (p < 0.05), but there was no significant difference between groups A and B. A diastolic/systolic peak velocity ratio < 0.6 predicted severe left internal mammary artery graft stenosis (> 75% diameter stenosis) with a sensitivity and specificity of 100% and 80%, respectively. The diastolic fraction of time-velocity integral was smaller in group C than in groups A and B (p < 0.05), but there was no significant difference between groups A and B. A diastolic fraction < 0.5 predicted significant left internal mammary artery graft stenosis (> 75% diameter stenosis) with a sensitivity and specificity of 90% and 100%, respectively. Conclusions. Duplex Doppler echocardiography from the supraclavicular fossa is useful for noninvasive assessment of left internal mammary artery graft patency.