Aortic Root Reconstruction and Valve Repair During Acute Type A Aortic Dissection Repair  Jared P. Beller, MD, Emily A. Downs, MD, Curtis G. Tribble, MD  Operative Techniques in Thoracic and Cardiovascular Surgery  Volume 22, Issue 2, Pages 80-90 (June 2017) DOI: 10.1053/j.optechstcvs.2018.02.002 Copyright © 2018 Elsevier Inc. Terms and Conditions

Figure 1 When performing the pericardiotomy, the surgeon must consider the possibility of a hemodynamically significant pericardial effusion. In the hypo- or normotensive patient, rapid decompression of the pericardial sac can lead to significant hypertension and catastrophic rupture of the aorta. A small incision is made in the pericardium to allow for controlled release of the tamponade. In addition, cardiopulmonary bypass can be initiated before opening the pericardium to help maintain appropriate blood pressure and provide additional control. Preoperative imaging should be reviewed, with specific focus given to determining the safest location for cannulation, which is often the axillary or femoral vessels. One can always convert to right atrial drainage once the pericardium is safely opened, and arterial outflow is transitioned to a side arm graft once the distal aortic anastomosis is complete. After the pericardial well is developed, the dissected aorta can be visualized with the planned line of proximal resection depicted by the dotted line—approximately 1-2 cm above the sinotubular junction. Operative Techniques in Thoracic and Cardiovascular Surgery 2017 22, 80-90DOI: (10.1053/j.optechstcvs.2018.02.002) Copyright © 2018 Elsevier Inc. Terms and Conditions

Figure 2 Once cardiopulmonary bypass is initiated the patient is cooled for 45 minutes to roughly 18°C. If there is significant aortic insufficiency, cross clamping of the aorta may be required to prevent left ventricular distention. However, significant distention can usually be avoided with venting via the right superior pulmonary vein. If cross clamping is required before circulatory arrest, this allows for repair of the root to be performed while cooling is completed. More often, appropriate temperatures are achieved without necessitating clamping the dissected aorta, and the distal repair can be completed first. If the arch is aneurysmal, or the entry tear is located within the aortic arch, arch replacement should be performed. In a normal aortic arch, a simple hemiarch repair with open anastomosis can be performed. For more extensive arch repair, a branched graft is utilized with anastomoses to the distal aorta, left common carotid artery, and innominate artery. The left subclavian artery is left in situ with the corresponding distal limb of the graft occluded with a vascular clip. This allows for a longer landing zone if subsequent endovascular grafting is required in the future. At times, an interval carotid to subclavian artery bypass will also be necessary. The distal aortic anastomosis is completed between the take-off of the left carotid artery and the left subclavian artery with a running 4-0 polypropylene suture on an SH needle with felt incorporated externally into the anastomosis. Cardiopulmonary bypass is then reinstituted through the side arm of the graft and flow is directed distally. Anastomoses of the branch grafts to the left common carotid and innominate arteries are performed sequentially. As the anastomoses are completed the clamp is moved proximally at each step to reinstitute flow to each of the reconstructed head vessels. Operative Techniques in Thoracic and Cardiovascular Surgery 2017 22, 80-90DOI: (10.1053/j.optechstcvs.2018.02.002) Copyright © 2018 Elsevier Inc. Terms and Conditions

Figure 3 After the distal reconstruction is completed (or during cooling in the case that requires aortic cross clamping), the sinuses of Valsalva are inspected and necessary extent of repair is determined based on the involvement of the sinuses. If the dissection involves the noncoronary sinus, or portions of either the left or right coronary sinus, the root is repaired. However, in the rare case of significant dilation of the root, known connective tissue disorder, or circumferential dissection, replacement is the preferred approach with either a valve sparing root procedure or a valved conduit. Thrombus is removed from the false lumen to allow for re-approximation of the layers of the aortic wall. If the dissection approaches a coronary orifice, it is gently probed with a right angle to confirm that there is no luminal obstruction. Operative Techniques in Thoracic and Cardiovascular Surgery 2017 22, 80-90DOI: (10.1053/j.optechstcvs.2018.02.002) Copyright © 2018 Elsevier Inc. Terms and Conditions

Figure 4 A thin piece of felt is fashioned, based on the anatomy of the dissection. Multiple pieces can be used and should be placed such as to fill the entire area between the dissected layers (neo-media). In cases where the noncoronary cusp is involved in isolation, a simple half moon is sufficient. If there is involvement of the tissue surrounding a coronary orifice, an incomplete ring can be added or more extensive configurations created to fill the false lumen. Extremely small pieces can be challenging to handle and should be avoided. At this point, it is important to again reconfirm that the geometry of the root has not been altered in such a way that coronary flow will be impaired. Operative Techniques in Thoracic and Cardiovascular Surgery 2017 22, 80-90DOI: (10.1053/j.optechstcvs.2018.02.002) Copyright © 2018 Elsevier Inc. Terms and Conditions

Figure 5 A small amount of BioGlue (CryoLife, Kennesaw, GA) is applied to encourage adherence between the tissue layers and the felt. It is important to avoid excessive administration or spillage of the glue. The primary surgeon ensures proper conformation by application of pressure with a thumb while applying the adhesive. The assistant should be ready with Russian forceps and pediatric-tip off table suction device to assist with positioning and control of excess glue. The assistant needs to be vigilant to ensure that no debris or glue enters the coronary orifices, which, if unrecognized, can lead to coronary occlusion. Debris, or excess glue in the aortic lumen, should also be noted but can usually be easily removed from the intima. Operative Techniques in Thoracic and Cardiovascular Surgery 2017 22, 80-90DOI: (10.1053/j.optechstcvs.2018.02.002) Copyright © 2018 Elsevier Inc. Terms and Conditions

Figure 6 The commissures are then resuspended with pledgetted sutures. Interrupted pledgetted 5-0 polypropylene sutures on an RB needle are used. There is rarely involvement of the left-right commissure and a suture at this location is therefore unnecessary, and may be omitted. However, an additional pledgetted suture at the base of the noncoronary sinus may be utilized to further reinforce the repair. Each of these sutures is then tied. Operative Techniques in Thoracic and Cardiovascular Surgery 2017 22, 80-90DOI: (10.1053/j.optechstcvs.2018.02.002) Copyright © 2018 Elsevier Inc. Terms and Conditions

Figure 7 Excess tissue above the sinotubular ridge is trimmed, leaving 5 mm of reconstructed aorta above the sinotubular ridge. Operative Techniques in Thoracic and Cardiovascular Surgery 2017 22, 80-90DOI: (10.1053/j.optechstcvs.2018.02.002) Copyright © 2018 Elsevier Inc. Terms and Conditions

Figure 8 A felt strip is fashioned and a running 4-0 polypropylene suture on an SH needle is used to complete the proximal anastomosis, incorporating the felt strip on the outside of the anastomosis. No additional felt is placed on the luminal side. A 32-mm graft is suitable for most patients, but at a minimum, 30-mm graft should be used. In the case of persistent aortic insufficiency after completion of cardiopulmonary bypass, this graft will be of sufficient diameter to accommodate insertion of a standard prosthetic valve. If there is a significant discrepancy in diameter of the distal aorta and aortic root, 2 different-sized grafts can be used which are then sewn together. However, we nearly always complete the aortic repair with a single multibranched graft. Operative Techniques in Thoracic and Cardiovascular Surgery 2017 22, 80-90DOI: (10.1053/j.optechstcvs.2018.02.002) Copyright © 2018 Elsevier Inc. Terms and Conditions

Figure 9 The proximal suture line is completed with external felt reinforcing the anastomosis. The patient is rewarmed and weaned from cardiopulmonary bypass. Mild central aortic insufficiency is well tolerated and will generally not progress in these patients. However, if there is moderate-to-severe eccentric aortic insufficiency, aortic valve replacement should be performed at this time. During the initial wean from cardiopulmonary bypass, right ventricular or segmental myocardial dysfunction should raise concern for inadequate coronary perfusion and should alert the surgeon to the need for coronary bypass. In the case of acute aortic dissections, it is our practice to always have a segment of greater saphenous vein prepared during the initial portion of the operation to facilitate rapid proximal coronary bypass with a short segment of vein, should this occur. Operative Techniques in Thoracic and Cardiovascular Surgery 2017 22, 80-90DOI: (10.1053/j.optechstcvs.2018.02.002) Copyright © 2018 Elsevier Inc. Terms and Conditions