Microvascular Coronary Artery Repair and Grafting in Infancy and Early Childhood  Joseph Catapano, MD, Ronald Zuker, MD, Osami Honjo, MD, PhD, Gregory Borschel, MD  Operative Techniques in Thoracic and Cardiovascular Surgery  Volume 20, Issue 2, Pages 148-161 (June 2015) DOI: 10.1053/j.optechstcvs.2015.11.001 Copyright © 2015 Elsevier Inc. Terms and Conditions

Figure 1 LIMA exposure and dissection. After standard sternotomy, the left sternal edge is retracted. Conventional adult sternal retractors for LIMA harvesting are not suitable for children. Therefore, retraction is achieved with hand retractors. An incision is made on the endothoracic fascia along the middle portion of LIMA. The LIMA is then harvested in a skeletonized fashion using very-low-current electrocautery. This can be done in a pedicle fashion as well. Large branches of LIMA are ligated with 8-0 polypropylene sutures on the arterial side. The sternal side branches are cauterized after division. If required for exposure, the internal mammary vein may be divided where it crosses the artery. After dissecting the entire LIMA length, the LIMA is divided immediately proximal to the major bifurcation to provide adequate length for the anastomosis, and is covered with a papaverine-soaked gauze to maintain patency. Operative Techniques in Thoracic and Cardiovascular Surgery 2015 20, 148-161DOI: (10.1053/j.optechstcvs.2015.11.001) Copyright © 2015 Elsevier Inc. Terms and Conditions

Figure 2 Appropriate positioning of the operating microscope. Microvascular anastomosis of small vessels requires 2 surgeons with training in microvascular techniques. The operating microscope should be placed to ensure the surgeon is in a comfortable position with the elbows and wrist supported in a position to reduce stress while operating. An operating microscope with imaging at 180° is best to ensure each surgeon is presented with an identical image of the operating field. Operative Techniques in Thoracic and Cardiovascular Surgery 2015 20, 148-161DOI: (10.1053/j.optechstcvs.2015.11.001) Copyright © 2015 Elsevier Inc. Terms and Conditions

Figure 3 Preserve collaterals of the left anterior descending artery. Microsurgical surgeons often ligate the collateral vessels close to the repair site to improve manipulation of the artery. However, in the cardiac scenario where collaterals are crucial for the cardiac musculature, special consideration and technical care must be taken to prevent damage to the collaterals and ensure the anastomosis is done with the collaterals intact. Operative Techniques in Thoracic and Cardiovascular Surgery 2015 20, 148-161DOI: (10.1053/j.optechstcvs.2015.11.001) Copyright © 2015 Elsevier Inc. Terms and Conditions

Figure 4 Appropriate selection of the arteriotomy site. The arteriotomy site is selected proximal to the first diagonal branch of the LAD. Using the excursion of the LIMA, special consideration must be taken to select an arteriotomy site that permits anastomosis of the LIMA without kinking of the artery. Additionally, the arteriotomy site should be made in an area without interference from adjacent collaterals. At our institution, we have had good results using a triangular ophthalmic knife to make the arteriotomy as opposed to an 11 blade that is much larger and may inadvertently puncture the opposite vessel wall. Flushing of the arteriotomy site with heparinized Ringer׳s solution is necessary to permit vessel visualization. Proximal and distal control can be obtained using vessel loops proximal and distal to the arteriotomy site. Operative Techniques in Thoracic and Cardiovascular Surgery 2015 20, 148-161DOI: (10.1053/j.optechstcvs.2015.11.001) Copyright © 2015 Elsevier Inc. Terms and Conditions

Figure 5 LIMA vessel preparation. The LIMA is transected obliquely to produce a spatulated transection. The LIMA must be cut at approximately a 45° angle to sufficiently cover the arteriotomy site. Transection of the artery at a 90° angle would result in greater rotation of the distal LIMA during anastomosis, increasing the risk of arterial kinking, reducing arterial inflow and potentially predisposing the patient to thrombotic complications. Vessel loops can be used to obtain proximal and distal control of the arteriotomy site on LAD. Both the LAD and LIMA are dissected at the site of anastomosis to remove adventitial tissue, which may inadvertently be incorporated into the anastomosis site. Operative Techniques in Thoracic and Cardiovascular Surgery 2015 20, 148-161DOI: (10.1053/j.optechstcvs.2015.11.001) Copyright © 2015 Elsevier Inc. Terms and Conditions

Figure 6 The heel of the LIMA is first sutured to the LAD. A single simple interrupted suture, using 10-0 Nylon on a BV-75-3μm needle is first placed at the heel of the LIMA to properly orient the heel of the LIMA to the proximal portion of the of LAD arteriotomy. Operative Techniques in Thoracic and Cardiovascular Surgery 2015 20, 148-161DOI: (10.1053/j.optechstcvs.2015.11.001) Copyright © 2015 Elsevier Inc. Terms and Conditions

Figure 7 A total of 2 additional sutures are then placed on either side of the first suture to stabilize the LIMA over the arteriotomy. Then 2 additional simple interrupted sutures, using 10-0 Nylon on a BV-75-3μm needle, are placed on either side of the first suture to reinforce the first, definitive heel suture. The heel region is susceptible to leaks, and so the sutures are placed close together. It is difficult to place additional sutures at the heel site once the anastomosis is completed. Operative Techniques in Thoracic and Cardiovascular Surgery 2015 20, 148-161DOI: (10.1053/j.optechstcvs.2015.11.001) Copyright © 2015 Elsevier Inc. Terms and Conditions

Figure 8 Repair of the back wall of the anastomosis. The back wall, which is the wall furthest from the suturing surgeon, is first repaired with simple interrupted sutures using a 10-0 Nylon suture on a BV-75-3μm needle. Typically, we use a total of 6 sutures to close a vessel with a diameter of 1mm. However, because this repair must withstand higher flows we increase the number of sutures placed with a stich approximately every 0.25mm. When there is a good size match of the donor LIMA and the recipient LAD and visualizations permits, we use a simple running suture to reduce the risk of leakage at the anastomosis site. Operative Techniques in Thoracic and Cardiovascular Surgery 2015 20, 148-161DOI: (10.1053/j.optechstcvs.2015.11.001) Copyright © 2015 Elsevier Inc. Terms and Conditions

Figure 9 Repair of the front wall of the anastomosis. The front wall, which is the wall closest to the suturing surgeon, is then repaired with simple interrupted sutures using 10-0 Nylon suture on a BV-75-3μm needle. Again, a suture is placed approximately every 0.25mm. If there is a good size match and visualization permits, a simple running suture can also be carried out on the front wall. Operative Techniques in Thoracic and Cardiovascular Surgery 2015 20, 148-161DOI: (10.1053/j.optechstcvs.2015.11.001) Copyright © 2015 Elsevier Inc. Terms and Conditions

Figure 10 The anastomosis is completed with 2 definitive toe sutures. The repair is then completed by placing 2 simple interrupted sutures at the toe of the repair again using 10-0 Nylon on a BV-75-3μm needle. These 2 sutures are placed with a delay tie technique, in which both sutures are placed before tying them down, making the placement of the final suture more precise and reliable. Alternatively, the suture tails may be tied to each other to complete the toe repair. Operative Techniques in Thoracic and Cardiovascular Surgery 2015 20, 148-161DOI: (10.1053/j.optechstcvs.2015.11.001) Copyright © 2015 Elsevier Inc. Terms and Conditions

Figure 11 Evaluation of the repair and addressing leaks. Occlusion of the LIMA is then released to monitor the anastomosis site for leaks. Leaks are repaired with simple interrupted sutures using 10-0 Nylon on a BV-75-3μm needle. Flow into the LAD is confirmed with visualization and intraoperative Doppler ultrasound. Operative Techniques in Thoracic and Cardiovascular Surgery 2015 20, 148-161DOI: (10.1053/j.optechstcvs.2015.11.001) Copyright © 2015 Elsevier Inc. Terms and Conditions