CARDIOVASCULAR JOURNAL OF AFRICA • Volume 33, No 5, September/October 2022 244 AFRICA and superior epigastric artery bifurcation using blunt and sharp dissection with an MEC (Medtronic Covidience Force Electrosurgical Generator, Minneapolis, USA). In group A, MEC output was adjusted to 20W and ‘coagulation’ mode, whereas the output current was increased to 40W in group B. Dissection started from the sternal edge lateral to the pleura, endothoracic fascia and venous comitantes in all patients. Grasping or retracting the ITA with forceps was avoided entirely in order to prevent graft injury. Proximal and distal haemostatic clips (Peters Surgical titanium haemostatic clips, small and medium size, France) to the ITA side branches and cautery division were preferred in group A. In this group, 15 to 25 metallic clips were used for this purpose (Fig. 1A). In group B, all the ITA side branches were directly devised by cautery at least 3 mm distally from the ITA main trunk. Approximately five to eight clips were placed on the stumps of the large side branches after the ITA was dissected (Fig. 1B). When the distal dissection reached the bifurcation, the musculophrenic branch was divided, and ITA harvesting extended to 2–3 cm distally to obtain maximal length, which occasionally is necessary. After an ideal length of ITA was prepared and a histological sample was extracted, ITA free flow was measured by pouring water through it and into a small bowl for 20 seconds. The amount was collected with a 50-ml syringe and multiplied by three to determine ITA free flow. Systolic blood pressure and heart rate were kept at about 90–100 mmHg and 60–80 beats/min during the ITA free-flow measurement to minimise haemodynamic involvement. Then 5 ml of 40-mg diluted papaverine HCl at 37°C was applied topically over the ITA pedicle, not directly into the ITA.5 After ITA harvesting, the 3–4-cm arterial sample, including the stump of the musculophrenic branch, was extracted from the distal part of the ITA. Harvested samples were divided into two pieces and fixed in 10% formaldehyde solution, dehydrated in graded concentrations of alcohol series and embedded in paraffin. After taking 3-µm sections, haematoxylin and eosin staining was performed. The histopathological evaluations were performed by two histologists independently and blindly. Histopathological results were noted as damaged or undamaged specimens. The undamaged specimen included: (1) the vessel wall was intact (×5), (2) the integrity of the endothelial cells and subendothelial elastic fibres were preserved (×40). Samples with a detached subendothelial layer (×5), irregular endothelial layer and separated subendothelial layer were accepted as damaged specimens. All patients with damaged ITA samples were followed up after one year and ITA patency was evaluated by angiography. Statistical analysis For statistical analysis, the SPSS version 24.0 program (SPSS Inc, Chicago, IL, USA) was applied. The normal distribution of variables was examined by histogram graphs and the Kolmogorov–Smirnov test. Mean and standard deviation values are used to present descriptive analyses. Fisher’s exact test was compared with 2 × 2 tables. While normally distributed (parametric) variables were evaluated among the groups, the Student’s t-test was used. The Mann–Whitney U-test was used to evaluate non-parametric variables. A p-value < 0.05 was evaluated as statistically significant results. Results The two groups were found to have similar co-morbid factors, which means they were comparable. The pre-operative baseline characteristics of the patients are shown in Table 1. The ITA harvest time was an average of twice as long in group A than in group B (21.2 ± 7.5 vs 10.3 ± 8.1 min, p < 0.001). Higher output of electrocautery facilitated the dissection. After harvest, ITA free flow was measured in the same fashion in all patients. The maximum and minimum free flow was measured as 118 and 36 ml/min, respectively. When comparing the two groups, no difference was found in terms of ITA free flow (43.6 ± 48.7 vs 51.7 ± 45 ml/min, p = 0.762) (Table 2). Neither ITA spasm nor gross haematoma was inspected in either group right after harvest. Fig I. Harvested internal thoracic artery (ITA) A: ITA harvested with 20W cautery, more than 20 peices of hemoclips were applied. B: ITA harvested with 40W cautery, less than 10 peices of hemoclips were applied. Fig I. Harvested internal thoracic artery (ITA) A: ITA harvested with 20W cautery, more than 20 peices of hemoclips were applied. B: ITA harvested with 40W cautery, less than 10 peices of hemoclips were applied. Fig. 1. Harvested internal thoracic artery (ITA). A: ITA harvested with 20W cautery, more than 20 pieces of haemoclips were applied. B: ITA harvested with 40W cautery, less than 10 pieces of haemoclips were applied. A B Table 1. Pre-operative clinical characteristics Variables Group A (n = 15) Group B (n = 15) p-value Age (years) 62.5 ± 7.1 64.1 ± 8.5 0.785* Female gender, n (%) 6 (40) 5 (33.3) 0.705** Body surface area (m2) 1.86 ± 0.21 1.88 ± 0.19 0.602* Body mass index (kg/m2) 26.9 ± 12.2 26.5 ± 12.8 0.540* Diabetes mellitus, n (%) 4 (26.7) 7 (46.7) 0.260** Hypertension, n (%) 6 (40) 4 (26.7) 0.441** Hyperlipidaemia, n (%) 3 (20) 4 (26.7) 0.667** Smoking, n (%) 8 (53.3) 5 (33.3) 0.273** Chronic obstructive pulmonary disease, n (%) 1 (6.7) 4 (26.7) 0.171** Number of bypass graft 3.7 ± 1.1 3.6 ± 0.9 0.521*** *Student’s t-test, **Fisher’s exact test, ***Mann–Whitney U-test.
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