Identifying the Left Anterior Descending Artery Target in Minimally Invasive CABG
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In this video, the authors present their approach for identifying the left anterior descending artery (LAD) target in minimally invasive robot-assisted CABG. They start with the robotic take down of the internal mammary artery (IMA), followed by a left minithoracotomy for the LAD anastomosis.
The first step in this procedure is a robotic IMA harvest. The authors start by placing robotic trocars, one superiorly and another inferiorly. For the authors’ instruments, they use a spatula cautery tip with micro bipolar forceps to take down the IMA as a pedicle. Once the pedicle is established, the branches are taken down using the micro bipolar forceps. This is a very safe approach for controlling the branches, and it also saves time by not exchanging the robotic arms for clip introduction. The robot also provides great visualization all the way up to the subclavian artery, as the video demonstrates. Once the surgeon is satisfied with the pedicle, heparin is given and the pericardium is opened widely, all the way from the apex of the heart to the right ventricular outflow tract. Once that is accomplished, the authors start their first method of identifying the LAD, which is robotic inspection.
As shown in the video, the apical LAD can be clearly identified. The authors also inspect medially to make sure there are no other vessels that can be visualized and only right ventricular muscle can be seen. Once that is performed, heparin has taken effect, and the IMA pedicle is clipped twice distally and once proximally using the robotic arm. Then the IMA is cut using endoscopic scissors. The IMA pedicle is tucked away to the apex of the lung so that it does not get injured with the thoracotomy incision. A long needle is used to identify the best intercostal space for working on top of the LAD exactly, by looking at the LAD and needle and deflating the CO2 insufflation.
Once the best space is established, the second method of identifying the LAD starts, which is direct inspection. This is very limited as the incision is very small, especially if rib spreading is not utilized. While the authors don’t depend on this method very much, it is reassuring to see the LAD exactly through the incision. They then move on to the next method, which involves utilizing transesophageal echocardiography (TEE).
This is the authors’ most important way of identifying the LAD. Directly through the incision, digital or soft instrument pressure to the left of the LAD target will show indentation of the right ventricle, as seen in the video. After that, pressure is applied to the right side of the target, and this should show indentation on TEE of the left ventricle. Pressure is then applied directly on the target itself, which should show indentation directly on the septum. This ensures that the surgeon definitely has the LAD target, as there is only one vessel that runs on the septum: the LAD.
After that is performed, a stabilizer is placed and the anastomosis can directly be performed in an off-pump manner.
Utilizing these three methods—robotic inspection, direct inspection, and TEE—the authors are able to identify the LAD in almost every case. Identifying the LAD is important in cases like this, where there are multiple diagonal branches running next to the LAD, which can easily confuse the surgeon as to which exactly is the LAD. The authors have found that TEE is the best method to identify the LAD target. These three methods allow the surgeon to give the patients smaller incisions and potentially, without rib spreading, allow faster recovery and return to work for patients who are candidates for this approach.