ObjectiveTo evaluate the changes of the flow parameters before and after the anastomotic port exploration and dredging during coronary artery bypass grafting by using the transit time flow measurement (TTFM).MethodsA total of 167 patients who underwent continuous coronary artery bypass grafting and anastomotic port exploration and dredging surgery in Beijing Anzhen Hospital from 2018 to 2019 were enrolled in this study. There were 136 male and 31 female patients aged 41-82 (58.35±17.26) years. If the probe entered and exited the anastomotic port smoothly, it was recorded as a non-resistance group; if the resistance existed but the probe could pass and exit, it was recorded as a resistance group; if the probe could not pass the anastomotic port for obvious resistance, it was recorded as the stenosis group. In the stenosis group, the grafts were re-anastomosed and the flow parameters were re-measured by TTFM.ResultsA total of 202 anastomotic ports were carried out by exploration and dredging. Among them, 87 anastomosis (43.1%) were in the non-resistance group, and there was no significant change in the blood flow volume (BFV) and pulsatility index (PI) before and after exploration and dredging (6.16±3.41 mL/min vs. 6.18±3.44 mL/min, P=0.90; 7.06±2.84 vs. 6.96±2.49, P=0.50). Sixty-four anastomosis (31.7%) were in the resistance group, the BFV was higher after exploration and dredging than that before exploration and dredging (17.11±7.52 mL/min vs. 4.96±3.32 mL/min, P<0.01), while the PI was significantly smaller (3.78±2.20 vs. 8.58±2.97, P<0.01). Fifty-one anastomosis (25.2%) were in the stenosis group, and there was no significant change in the BFV and PI before and after exploration and dredging (3.44±1.95 mL/min vs. 3.48±2.11 mL/min, P=0.84; 10.74±4.12 vs. 10.54±4.11, P=0.36). After re-anastomosis, the BFV was higher (16.48±7.67 mL/min, P<0.01) and the PI deceased (3.43±1.39, P<0.01) than that before exploration and dredging.ConclusionThe application of anastomotic exploration and dredging can reduce the occurrence of re-anastomosis, and promptly find and solve the stenosis of the distal coronary artery, improve the poor perfusion of distal coronary, and thus improves the prognosis of patients.