الفهرس 
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Abstract
Complete Revascularisation and arterial grafting are recognized with improved long term outcomes after CABG. The internal mammary artery (IMA) has been established as the preferred conduit For CABG. The advantages of bilateral IMA over single IMA grafting have been demonstrated with regard to survival, freedom from repeat angioplasty, reoperations, and event-free survival. Numerous arrangements of BIMA grafting have been anticipated to accomplish full left-sided myocardial revascularization. The strategies used for BIMA grafting for left-sided myocardial revascularization are retro-sternal crossover in-situ RIMA to LAD with in-situ LIMA to circumflex marginal branches, retro-aortic in-situ RIMA through transverse sinus to circumflex marginal branches with in-situ LIMA to LAD and composite LIMA-RIMA T or Y grafting. The advantage of one technique over the other and proper ways for the choice of either method is not established yet.
The first strategy (crossover in-situ RIMA to LAD) is technically less demanding, having the principle of dual-origin blood supply. The extra-length achieved by harvesting the BIMA as a skeletonised vessel allows better selection of the LAD anastomotic site and avoids usage of the more distal vasospastic RIMA segments. A main disadvantage of this technique is the possible danger of injury to the artery throughout re-sternotomy.
The second strategy (RIMA through transverse sinus) offers many advantages: the LAD is revascularised with the in-situ LIMA, which is accepted as a gold standard technique. The left coronary system is perfused by 2 in situ IMAs. There are no grafts passing through the midline behind the sternum, and BIMAs are in a safe position, which reduces the danger in case of mediastinal revision or reoperation. The main disadvantages of the retro-aortic course of the in-situ RIMA are the inability to control bleeding from retro-aortic RIMA branches, aortic compression of the in-situ RIMA, and compromised graft patency because of undetected kinks, graft overstretching, rotation, and spasm of distal RIMA.
The last strategy (composite LIMA-RIMA T or Y grafting) has the advantage of being ideally matched and avoiding the problems of proximal anastomoses to the aorta, the aortic “no touch” technique decreases the risk of cerebrovascular accidents and is useful in OPCAB, and a greater length of RIMA is available for more extensive myocardial revascularization. On the other hand, single source blood supply with steal phenomenon, competitive flow, and hypoperfusion syndrome are some of the well-recognised concerns associated with composite grafting.
This study was conducted prospectively on all patients who underwent isolated first time CABG by using bilateral internal mammary arteries to revascularize left coronary system for one year from December 2016 to December 2017 at Alexandria main University Hospitals and Sharq Al-Madina Hospital in Alexandria, Egypt. The technique used for anastomoses was according to the preference of the participating surgeons after reviewing the patient’s data.
Patients were divided into two groups according to the surgical technique:
• group A (single source blood supply group for the left system): consisted of 21 patients, who were treated with the BIMA composite Y or T grafts (n=21).
• group B (double source blood supply group for the left system): consisted of 16 patients, who were treated with the 2 in situ BIMA not composite Y or T fashion (n=16).
The two groups had comparable preoperative risk profiles except hypertension was significantly more within group A in 14 cases (66.7%) compared to group B who had only 5 patients (31.3%). Bypass time and aortic cross-clamping time were longer in the composite group (107.4±24.73 and 68.10±16.77 minutes versus 91.88±35.96 and 56.88±25.94 minutes, respectively). Number of anastomoses per patient was similar (3 versus 3). However, the sequential anastomoses were performed in group A (9.6%).
In group A (n=21), the BIMAs (all skeletonized) were used in composite T or Y grafts where the LIMA was used for the LAD anastomosis in the 21 cases. The RIMA was targeted distally to the OM in 16 cases, OM2 in 1 case and Ramus in 2 cases. The Composite RIMA was targeted sequentially to OM1, OM2 in 1 case, and to OM2, OM3 in 1 case. SVG grafts were used to revascularize the rest of the territories. In group B (n=16), the BIMAs (all skeletonized) were used, where the in-situ LIMA was used for the LAD anastomosis in 2 cases, OM in 12 cases, Ramus in 1 case and Diagonal in 1 case. The in-situ RIMA was targeted distally to the LAD in 14 cases and OM (retro-aortic) in 2 cases. SVG grafts were used to revascularize the rest of the territories. Endarterctomy to LAD was done in 3 cases (18.8%).
In group A; postoperative complications were encountered only in 1 patient (4.8%), this patient had an attack of rapid AF, while in group B, postoperative complications were encountered in 5 patients (31.5%); 1 patient (6.3%) had an attack of rapid AF, 1 patient (6.3%) had superficial wound infection ( E.coli), Preoperative risk factor for this patient was renal impairment, this patient was managed medically and another patient (6.3%) encountered superficial wound infection ( E.coli) and managed medically. Postoperative exploration for bleeding was encountered only in one patient (6.3%) in group B (900 CC in 3 hours postoperative) and the source of bleeding was the musculophrenic artery (distal stump of LIMA).
Difficult weaning from ventilator and chest infection was encountered only in one patient (6.3%) in group B (144 hours on mechanical ventilator) and sputum culture for this patient was done and revealed staphylococcus aureus. Preoperative risk factors for this patient were COPD and heavy smoking.
No Major Adverse Cardiac Events (MACEs) was recorded in both groups and IABP support not required in both groups.