Objective To investigate the use of intraoperative transit time flow measurement （TTFM） to accuratelyevaluate graft patency during sequential coronary artery bypass grafting （CABG）. Methods Clinical data of 131 patientsundergoing sequential off-pump coronary artery bypass grafting （OPCAB） with the great saphenous vein （with or without internal mammary artery） as graft vessels in Beijing Anzhen Hospital from April 2012 to January 2013 were retrospectivelyanalyzed. There were 92 male and 39 female patients with their age of 61.35±8.24 years. During the operation，2 methods were used to measure mean blood flow volume，pulsatility index （PI） and diastolic filling （DF） of the graft vessels. For thenon-blocking method，blood flow in graft vessels was maintained，and TTFM was applied 2 cm proximal to the anastomoticsite in graft vessels to record above parameters. For the blocking method，blood flow in graft vessels was temporally blockedby clipping distal graft vessels with an atraumatic bulldog clamp，and TTFM was applied 2 cm proximal to the anastomotic site in graft vessels to record above parameters. Results Blood flow volumes of the diagonal branch （27.43±15.22 ml/minvs. 59.28±30.13 ml/min），obtuse marginal branch （26.14±19.74 ml/min vs. 47.19±24.27 ml/min） and posterior left ventr-icular branch （19.16±8.92 ml/min vs. 38.83±20.11 ml/min） measured by the blocking method were significantly smallerthan those measured by the non-blocking method （P＜0.05） . PI values of the diagonal branch （2.93±1.30 vs. 2.31±0.91），obtuse marginal branch （2.62±1.17 vs. 2.01±0.87） and posterior left ventricular branch （2.33±0.92 vs. 1.80±0.73） meas-ured by the blocking method were significantly higher than those measured by the non-blocking method （P＜0.05）. There was no statistical difference in DF values measured by 2 methods at respective anastomotic sites，and all DF values were higher than 50%. Non-blocking method identified 1 anastomotic site and blocking method identified 3 anastomotic sites that were not patent，and these anastomotic sites became patent after graft reconstruction. Conclusion Blood flow velocity of sequential grafts is higher than that of single grafts，indicating that sequential grafts have the advantages of high blood flow volume and low risk of thrombosis. Blocking method can more accurately evaluate graft patency at the anastomotic sites and sensitively identify graft vessels that are not patent，which is helpful for anastomotic site reconstruction in time and enhancement of successful rate of CABG.
ObjectiveTo evaluate immediate outcomes of 8-0 Prolene sutures for distal anastomosis during off-pump coronary artery bypass grafting (OPCAB). MethodsA total of 101 patients who underwent OPCAB in Department of Cardiac Surgery of Beijing Anzhen Hospital in 2010 and 2012 respectively were enrolled in this study. There were 87 male and 14 female patients with their age of 46-82 (61.35±8.24)years. All the 36 patients in 2010 received 7-0 Prolene sutures for distal anastomosis, and the 65 patients in 2012 received 8-0 Prolene sutures for distal anastomosis. After anastomosis, transit time flow measurement was used to measure blood flow indexes of graft vessels[left internal mammary artery (LIMA)and saphenous vein (SV)] including blood flow volume (BFV), pulsatility index (PI)and diastolic filling fraction (DF), which were compared between patients receiving 7-0 and 8-0 Prolene sutures. ResultsBFV of LIMA grafts with 8-0 Prolene sutures (n=44)was significantly larger than that with 7-0 Prolene sutures (n=30)[ (33.70±21.13)ml/min vs. (27.50±17.34)ml/min, P=0.032], while PI of LIMA grafts with 8-0 Prolene sutures was significantly smaller than that with 7-0 Prolene sutures (2.15±0.69 vs. 2.58±1.01, P=0.047). BFV and PI of SV grafts with 8-0 Prolene sutures (n=21) were not statistically different from those with 7-0 Prolene sutures (n=6)[ (34.19±16.00)ml/min vs. (29.00±15.48)ml/min, P > 0.05;2.07±0.53 vs. 1.95±0.55, P > 0.05]. DF of all the grafts was greater than 50%, and there was no statistical difference in DF between the 2 groups (P > 0.05). Conclusion8-0 Prolene sutures for LIMA-to-left anterior descending artery can improve BFV and decrease PI of LIMA grafts, which reflects better immediate graft patency of the distal anastomosis and helps improve surgical success rate and long-term prognosis.
Transit time flow measurement (TTFM),which is independent of vessel size and shape, has been considered to be an easy, reproducible and non-invasive method to assess the hemodynamic characteristics. Moreover, current studies have shown that TTFM has clinical application in identifying the function of grafted vessel and prognosis. Researchers have proved some reliable indicators for the function of grafted vessel as follows: mean graft flow (MGF) > 15 ml/min, diastolic flow (DF) >50% and pulsatility index (PI)<3 or 5. This article focuses on the review of clinical application and research progress of TTFM in CABG.