A prospective comparison of Doppler echocardiography and postoperative angiography in the assessment of left internal thoracic artery graft in 72 patients submitted to minimally invasive direct coronary artery bypass.

BACKGROUND

Concerns have been raised regarding the accuracy of the left internal thoracic artery (LITA) anastomosis performed during minimally invasive direct coronary artery bypass (MIDCAB). In a prospective study, we tested the hypothesis that transthoracic Doppler echocardiography is an adequate technique to determine LITA patency when compared to "gold standard" postoperative angiography.

METHODS

Seventy-two consecutive patients with single left anterior descending (LAD) coronary artery stenosis were submitted to MIDCAB performed on a beating heart using the LITA. All patients underwent transthoracic Doppler Echocardiography and angiography before discharge. LITA was considered patent when diastolic fraction (DF) of time-velocity integral was equal or greater than 0.5. FitzGibbon grading system was used to evaluate LITA patency by angiography (A=excellent; B=stenosis reducing caliber of anastomosis or trunk to < 50% of grafted coronary artery; O=occlusion).

RESULTS

Angiography showed that LITA was patent in 70 (97.2%) patients, 69 of them been graded A. Adequate image and flow signal of the LITA was achieved in 65 (90.3%) patients, been considered patent in 61 (93.8%) of them. Comparison between echocardiography and angiography in these 65 patients showed a specificity of 96.8% and a sensitivity of 50%. In 7 (9.7%) patients in whom no adequate echocardiography signal was obtained, the LITA graft was normal in six and occluded in one.

CONCLUSIONS

For patients whose LITA graft can be imaged, transthoracic Doppler echocardiography is highly specific and is a valuable method for noninvasive evaluation of LITA graft patency after MIDCAB.