Transthoracic 2D echo color Doppler assessment of internal mammary artery to left anterior descending coronary artery graft.

Abstract

For noninvasive evaluation of anatomy and flow characteristics of internal mammary artery graft (IMA-graft), 2D echo-Color-Doppler (CDE) was performed in 60 patients (54 M, 6 F, mean age 54.1 +/- 6.9 y), who underwent coronary angiography 20.1 +/- 13 months after a coronary artery bypass graft (CABG). CDE was performed, using an echocardiographic unit equipped with a 5 MHz linear transducer. In all patients, measurements of IMA-graft diameter (mm), and peak systolic and diastolic flow velocity (cm/sec) were obtained at baseline and also in 16 patients after dipyridamole infusion (0.54 mg/Kg/min) and in 10 patients after sublingual nitroglycerin (NTG) (0.4 mg). Angiography showed the IMA-graft patency in 58/60 patients (96.8%). A typical biphasic flow was displayed by CDE in 49/58 patients (84.4%) with angiographic patency. Dipyridamole infusion increased both IMA-graft diameter and peak diastolic flow velocity (PDFV) from 2.28 +/- 0.51mm to 2.9 +/- 0.42mm and from 19.4 +/- 6.2 cm/sec to 93.9 +/- 29 cm/sec, respectively (p < 0.0001). No significant modifications of peak systolic flow velocity (PSFV) were observed. NTG increased PDFV from 29.11 +/- 8 cm/sec to 41.88 +/- 7.20 cm/sec (p < 0.005), while diameter and PSFV showed no statistically significant modifications. CDE is a useful diagnostic tool for noninvasive evaluation of IMA-graft patency both early after surgery and during long-term follow-up. CDE pharmacological stress improves the sensibility of the technique and it can provide indirect information about pathophysiology of recipient coronary vessel.