Background: The patent internal thoracic artery graft (ITAG) usually has a diastolic fraction (DF) > 50% of the flow. The functional assessment can be evaluated by the coronary reserve index (CRI).
Objective: The objective was to evaluate the patency and functional status of the ITAG through echocardiography and Doppler.
Methods: Data from sixty-six patients who underwent dobutamine-stress echocardiography (DSE) were prospectively collected and analyzed. Group I (GI) had 49 ITAG without stenosis, Group II (GII), 10 ITAG with significant stenosis (> 50% and <100%) and Group III (GIII) had 7 ITAG with total occlusion. Diameters and Doppler spectrums from the ITAG at rest and during DSE were evaluated.
Results: Considering patency a DF >50%, it was observed in 49 ITAG (GI= 40, GII= 8 and GIII= 1) at rest and in 61 ITAG (GI=49, GII=10 and GIII=2) during DSE. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy were respectively, 81%, 86%, 98%, 35% and 82%, and 100%, at rest and 71%, 97%, 100% and 97% in the DSE. The ITAG with DF>50% at rest were patent and the ones with DF<50% in the DSE presented total occlusion. Considering a CRI>1.8 for a good functional status, it was observed in 42 ITAG (39 from GI, 2 from GII and 1 from GIII), determining sensitivity=79%, specificity=85.7%, PPV=94%, NPV=59% and accuracy= 80.9%. The CRI in GI was higher (p= 0.02) than in GII or GIII.
Conclusion: In our study, the non-invasive assessment of the ITAG was effective to verify the patency and the functional status.