CARDIOVASCULAR JOURNAL OF AFRICA • Volume 34, No 4, September/October 2023 AFRICA 245 two of the patients in group 1 with this administration. The administration also led to the renewal of the anastomosis and improvement in the PI values of one patient. Moreover, PI values increased with local papaverine administration and position changes in two patients from group 2. The circumflex (Cx) anastomosis was renewed in one patient in group 2. In group 3, saphenous distal anastomoses were renewed in two grafts. Position changes proved sufficient for two grafts. For two patients, flow was increased through the use of locally administered drugs. Anastomosis revisions were performed with the support of the Octopus on the beating hearts of all patients. Although TTFMs were low in the saphenous vein grafts of group 3, none of these patients experienced significant electrocardiogram changes or haemodynamic problems. In only one of the patients (group 1), a percutaneous intraaortic balloon pump was placed at the end of the CPB when the blood pressure was not sufficient despite inotropic support. There were no significant differences between groups 1 and 2 in terms of inotropic support that was initiated postoperatively. There was significantly less inotropic support in group 3 (p < 0.05). Although the mean number of grafts that was used in the patients who underwent operation on the beating heart was lower than in the other two groups, this difference was not statistically significant. Discussion Aortocoronary bypass graft operations have been successfully performed to treat severe diseases and conditions of the coronary artery for many years. As in all surgeries, improvements have been made to coronary bypass surgery over time. However, discussions on which methods result in the most successful anastomoses and surgeries are ongoing. Among coronary artery bypass surgeries, anastomosis quality is considered to be a low priority, especially in surgeries performed on the beating heart.7 In addition, many studies have suggested that revascularisation cannot be completed in patients who undergo surgery using this method.8 Early intervention and intra-operative evaluation of graft patency and quality are critical to surgical success. Detecting and solving technical problems during the intra-operative period is particularly effective in reducing the early occlusion of saphenous vein grafts. Tensions due to insufficient graft length and technical deficiencies in anastomosis can be effective in early graft occlusions.9,10 Although different methods have been developed to measure anastomosis quality (intra-operative angiography, thermal angiography, electromagnetic graft flow measurement), several studies have suggested that TTFM is more useful due to its easy application and lower cost.11-13 In line with these studies, we used the TTFM method to evaluate the quality of grafts in different surgical methods that were performed at our clinic. In the recent study by Kaya et al. that evaluated 1 240 patients and 3 596 graft measurements at our clinic, TTFM proved to be quite effective at detecting peri-operative graft failure.14 In another study at our clinic that compared two groups with and without TTFMs, mortality, peri-operative and postoperative myocardial infarction, additional intervention when necessary, and the need for intra-aortic balloon pump support were found to be lower in the group with TTFMs.15 The data obtained with this method are presented as the PI, DF and mean flow. Although these cannot individually be used to sufficiently evaluate the quality of anastomosis, low graft flow is interpreted to represent an error in anastomosis. Some studies have indicated that mean flow values are not directly correlated with clinical outcome and graft patency in the long term.16,17 Despite the present study’s use of three different techniques, we did not detect any significant differences between the mean flow values of the grafts. Many studies have observed that comparisons that only involve the mean flow value are insufficient. It is possible to obtain high graft flow with a stenotic anastomosis. The study by Jaber et al. illustrated that there was no serious deterioration in the mean flow value when stenosis of the anastomoses remained below 75%.18 The PI is accepted as the most important parameter for determining the quality of anastomosis. In a study based on these values that compared on-pump with off-pump surgery, the results were in favour of on-pump surgery.19 In the present study, the PI values in group 1 were significantly lower than in the other groups. However, there were no significant differences between the groups in terms of the number of patients with PI values that required intervention. In other words, the mean PI values in the three groups were within acceptable limits. Because the basis of our study was to detect and compare intra-operative measurements and additional intra-operative surgical interventions, if necessary, no comment was made on the long-term results of the grafts. Nonetheless, we believe that intra-operative comparisons of these data can prove highly useful in comparing anastomosis quality between surgical techniques. Studies in the literature have indicated that acidosis20 and related coronary vasodilation21 develop in coronary systems during off-pump surgery. However, in the current study, a significant difference was detected in only the PI values of group 1 among the TTFMs in all three groups that had undergone operations with on-pump and off-pump surgical techniques. All groups were similar in the number of patients who presented PI values that were below the acceptable level (PI < 5).We believe that the absence of any significant differences between the TTFMs of patients undergoing on-pump operations through induced cardiac arrest, patients undergoing on-pump operations without induced cardiac arrest, and patients undergoing operations on the off-pump beating heart were due to the sufficient clinical experience involved in all three methods. Table 4. Transit time flow measurement values Variable LIMA–LAD p-value Ao–Cx p-value Ao–RCA p-value Ao–DIA p-value PI Group 1 3.03 ± 1.54 0.001 3.71 ± 1.87 0.438 3.35 ± 2.05 0.313 2.45 ± 0.81 0.001 Group 2 3.91 ± 0.98 3.72 ± 1.3 4.94 ± 6.38 4.01 ± 0.68 Group 3 3.95 ± 0.77 3.83 ± 0.83 4.01 ± 0.91 3.94 ± 0.77 HR Group 1 59.92 ± 30.04 0.461 52.46 ± 24.27 0.857 57.78 ± 27.63 0.880 62.57 ± 33.59 0.980 Group 2 55.18 ± 20.39 51.15 ± 13.36 54.87 ± 17.48 59.67 ± 19.93 Group 3 63.31 ± 23.83 56 ± 21.38 57.93 ± 18 57.1 ± 20.46 DF Group 1 72.6 ± 7.54 0.403 66.59 ± 10.91 0.013 57.69 ± 13.71 0.021 68.27 ± 12.35 0.992 Group 2 71.91 ± 8.68 59.48 ± 10.04 64.96 ± 7.73 67.78 ± 5.7 Group 3 69.72 ± 11.76 68 ± 8.28 65.86 ± 9.42 68 ± 10.02 PI: pulsatility index, HR: heart rate, DF: diastolic filling, LIMA: left internal mammary artery, LAD: left anterior descending artery, Ao: aorta, Cx: circumflex artery, RCA: right coronary artery, DIA: diagonal artery.
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