Transesophageal Echocardiographic Estimation of Coronary Sinus Blood Flow for Predicting Favorable Postoperative Transit Time Coronary Graft Flow Measurements: A Pilot Study.

BACKGROUND: Augmentation of coronary artery flow by surgical grafting increases coronary sinus blood flow (CSBF), which can be quantified on transesophageal echocardiography (TEE). However, transit time flowmetry (TTF) technology remains the most used intraoperative technique for coronary artery graft assessment. The purpose of the present pilot study was to evaluate the predictive value of TEE-based CSBF estimation for identifying favorable TTF graft measurements. DESIGN: Prospective observational study. SETTING: Single university hospital. PATIENTS: Forty patients undergoing triple vessel coronary artery bypass grafting. MEASUREMENTS AND MAIN RESULTS: CSBF was assessed on TEE examination before and after revascularization, estimating the percentage increase in CSBF (∆CSBF). Postoperative TTF graft measurements were averaged to compute mean diastolic filling (DF) and pulsatility index (PI). Subjects were grouped based on favorable (PI ≤ 3, DF ≥ 50%) and unfavorable (PI > 3, DF < 50%) parameters. The group with PI ≤ 3 (n = 32) had significantly higher ∆CSBF compared with the group with PI > 3 (n = 8) (38.22% ± 12.05%, 13.75% ± 3.37%, p < 0.001). ∆CSBF was higher in the DF ≥ 50% group (n = 35) (36.40 ± 12.99) in contrast to DF < 50% group (n = 5) (11.80 ± 2.59%). A strong negative and significantly positive correlation was observed between ∆CSBF with PI, DF (r = -0.903, 0.571, respectively, p < 0.001). A ∆CSBF ≥15.5% was found to predict a mean PI ≤ 3 and DF ≥ 50% with sensitivity and specificity of 100% and 62.5% for PI and 100% and 100% for DF. A ∆CSBF ≥19% demonstrated a sensitivity and specificity of 100% and 100%, 100% and 91.4% for prediction of PI ≤ 3 and DF ≥ 50%, respectively. CONCLUSION: TEE-based demonstration of an augmented CSBF can ensure favorable TTF graft parameters, guiding the adequacy of surgical revascularization.