Surgical Unroofing for Anomalous Aortic Origin of Coronary Arteries Sarah A. Schubert, MD, Irving L. Kron, MD  Operative Techniques in Thoracic and Cardiovascular Surgery  Volume 21, Issue 3, Pages 162-177 (September 2016) DOI: 10.1053/j.optechstcvs.2017.07.001 Copyright © 2017 Terms and Conditions

Figure 1 (A) A cross-sectional view of the aortic root demonstrates a normal left main coronary artery arising from the left sinus of Valsalva. The right coronary artery, however, also originates from the left sinus of Valsalva, usually through a slit-like opening or with an abnormal ridge of tissue within the ostial orifice. The course of the right coronary artery then courses intramurally toward the right coronary cusp, at which point it emerges and follows its normal course to perfuse the right heart. (B) The inset demonstrates a normal right coronary artery arising from the right sinus of Valsalva. The left main coronary artery, however, also originates from the right sinus of Valsalva, usually through a slit-like opening or with an abnormal ridge of tissue within the ostial orifice. The course of the left main coronary artery then courses intramurally toward the left coronary cusp, at which point it emerges and follows its normal course to perfuse the intraventricular septum and the left lateral wall of the heart. SVC = superior vena cava. Operative Techniques in Thoracic and Cardiovascular Surgery 2016 21, 162-177DOI: (10.1053/j.optechstcvs.2017.07.001) Copyright © 2017 Terms and Conditions

Figure 2 (A) In this anterior-posterior view of the heart, the course of the coronaries along the external surface of the heart appears grossly normal; however, the right coronary artery ostium is located within the left sinus of Valsalva, with the proximal portion of the coronary traveling within the wall of the ascending aorta and then coursing normally along the acute margin of the heart. Although isolated coronary anomalies are relatively rare and is thought to occur in only about 1% of the population, the incidence of anomalous aortic origin of coronary arteries from the opposite sinus of Valsalva is even more rare, with the incidence of the right coronary arising from the left sinus of Valsalva approximated at 0.05%-0.1%.1 The true incidence of the defect, however, is unknown, as there is a selection bias toward patients who have ischemic symptoms and are thus are more likely to undergo cardiac catheterization and identify an anomalous coronary. (B) The left main coronary artery ostium is located more anteriorly within the right sinus of Valsalva. To reach its normal course along the obtuse margin and the anterior surface of the heart, the left main coronary artery lies within the aortic wall and then emerges on the surface of the heart, and normally divides into the left circumflex and the left anterior descending coronary arteries. The incidence of a left main coronary artery from the right sinus of Valsalva is even less than that of a right coronary artery arising from the left sinus of Valsalva, estimated at 0.03%-0.05%.1 Despite being less common, the mortality associated with a left main coronary artery from the right sinus is reported to be greater than that associated with a right coronary artery arising from the left sinus of Valsalva.20 Pathologic variables that may account for these mortality differences include longer intramural courses, coursing of the coronary between the aorta and the pulmonary artery, an acute takeoff of the coronary relative to the aorta, and a slit-like coronary ostium.20 Operative Techniques in Thoracic and Cardiovascular Surgery 2016 21, 162-177DOI: (10.1053/j.optechstcvs.2017.07.001) Copyright © 2017 Terms and Conditions

Figure 3 The initial operative steps in the unroofing of an anomalous coronary artery include standard cannulation techniques for a cardiopulmonary bypass. Following a median sternotomy and the creation of a pericardial well, purse string sutures are placed in the distal ascending aorta, and an aortotomy is made into which an aortic cannula is placed and secured with Rummel tourniquets. Depending on what concomitant operations, if any, are being performed with the unroofing of the coronary artery, venous cannulation with a dual-stage venous cannula through a right atriotomy can be established, and the cannula can be secured with a Rummel tourniquet around a purse string suture placed in the right atrium. It is our practice to place this purse string around the right atrial appendage and to create the atriotomy by using Metzenbaum scissors to cut off the tip of the right atrial appendage. Bicaval venous cannulation via the superior and the inferior vena cavae (not pictured) can also be used, if necessary, for atrial exposure in concomitant operations. Following the establishment of aortic and venous cannulations, an aortic root vent is placed in the ascending aorta proximal to the aortic cannula to allow drainage of the aortic root and the administration of antegrade cardioplegia. A left ventricular venting cannula is placed in the right superior pulmonary vein to allow adequate exposure and drainage of the left ventricle. A retrograde cardioplegia catheter is placed in the coronary sinus for additional cardioplegia protection of the myocardium. Once the patient has been adequately anticoagulated, cardiopulmonary bypass can then be initiated, and the patient is cooled to 32-34°C. The cross clamp can then be applied to the ascending aorta between the root vent and the aortic cannula. Cold-blood retrograde and anterograde cardioplegia is used to arrest the heart and is repeated approximately every 20 minutes to reinforce cardiac arrest throughout the course of the operation. Operative Techniques in Thoracic and Cardiovascular Surgery 2016 21, 162-177DOI: (10.1053/j.optechstcvs.2017.07.001) Copyright © 2017 Terms and Conditions

Figure 4 Following a cardioplegic arrest of the heart, the aortic root vent can be removed, and a transverse aortotomy is made approximately 2 cm distal to the sinotubular junction. The aortotomy is then extended parallel to the annulus of the aortic valve. A stay suture can be placed in the distal portion of the divided ascending aorta to allow adequate visualization of the aortic root (not pictured). With the aortic root opened, there are 2 orifices noted within the right sinus of Valsalva, a normal-appearing right coronary ostium and a small slit-like ostium for the left coronary artery. Operative Techniques in Thoracic and Cardiovascular Surgery 2016 21, 162-177DOI: (10.1053/j.optechstcvs.2017.07.001) Copyright © 2017 Terms and Conditions

Figure 5 Once the 2 ostia have been definitively identified within the aortic root, a small right angle clamp is gently placed into the ostia of the anomalously located at the left coronary artery. With the clamp inside the coronary, a #15 blade is used to unroof the overlying common wall of the coronary artery and the aorta. About 1.0-1.5 cm of the intramural coronary is unroofed. Operative Techniques in Thoracic and Cardiovascular Surgery 2016 21, 162-177DOI: (10.1053/j.optechstcvs.2017.07.001) Copyright © 2017 Terms and Conditions

Figure 6 (A) In some instances, the intramural portion of the coronary may cross the from 1 aortic sinus into the next by traversing the commissural plane, rather than being completely above the commissure, as illustrated with an anomalous left coronary artery in this figure. A typical unroofing procedure in which the length of the intramural portion is incised is contraindicated as that would disrupt the aortic valve leaflets. LAD = left anterior descending coronary artery. Operative Techniques in Thoracic and Cardiovascular Surgery 2016 21, 162-177DOI: (10.1053/j.optechstcvs.2017.07.001) Copyright © 2017 Terms and Conditions

Figure 6 Continued (B) In these instances, the commissure is detached, and the intramural portion of the coronary is unroofed. Operative Techniques in Thoracic and Cardiovascular Surgery 2016 21, 162-177DOI: (10.1053/j.optechstcvs.2017.07.001) Copyright © 2017 Terms and Conditions

Figure 6 Continued (C) The detached commissure is then resuspended above the unroofed intramural segment with a pledgetted suture. Operative Techniques in Thoracic and Cardiovascular Surgery 2016 21, 162-177DOI: (10.1053/j.optechstcvs.2017.07.001) Copyright © 2017 Terms and Conditions

Figure 6 Continued (D) When the commissure crosses only a small portion of the intramural coronary segment, the unroofing can be carried out on either side of the commissure, thus leaving the commissure intact and not disturbing leaflet motion. Operative Techniques in Thoracic and Cardiovascular Surgery 2016 21, 162-177DOI: (10.1053/j.optechstcvs.2017.07.001) Copyright © 2017 Terms and Conditions

Figure 6 Continued (E) Reimplantation of the coronary into the correct sinus is another viable option when the anomalous segment is closely related to the commissure. The intramural portion of the artery is unroofed, and the proximal left coronary is mobilized. Operative Techniques in Thoracic and Cardiovascular Surgery 2016 21, 162-177DOI: (10.1053/j.optechstcvs.2017.07.001) Copyright © 2017 Terms and Conditions

Figure 6 Continued (F) The left coronary is reimplanted into the correct left sinus. The aortic wall defect remaining after the excision of the coronary button can be patched with bovine pericardium or a similar patch material. Operative Techniques in Thoracic and Cardiovascular Surgery 2016 21, 162-177DOI: (10.1053/j.optechstcvs.2017.07.001) Copyright © 2017 Terms and Conditions

Figure 7 After the intramural segment of the anomalous coronary artery is unroofed, a neo-ostium is created in the correct sinus of Valsalva. To prevent an intimal dissection at this neo-orifice, interrupted tacking sutures using a 7-0 monofilament suture are placed circumferentially around the ostium, thus securing the coronary intima to the aortic wall. Operative Techniques in Thoracic and Cardiovascular Surgery 2016 21, 162-177DOI: (10.1053/j.optechstcvs.2017.07.001) Copyright © 2017 Terms and Conditions

Figure 8 Following completion of the unroofing and any other concomitant procedures, the aortotomy is closed in 2 layers with a running monofilament suture. The aortic root vent should also be replaced to allow adequate deairing of the heart before the removal of the cross clamp. While completing the aortotomy closure, the perfusion team can begin to rewarm the patient to prepare for separation from the cardiopulmonary bypass. The left ventricular and aortic root vents and the retrograde cardioplegia catheter can be removed, and weaning from bypass can then begin. Once the patient is weaned from bypass, the patient can be decannulated in the standard fashion. Operative Techniques in Thoracic and Cardiovascular Surgery 2016 21, 162-177DOI: (10.1053/j.optechstcvs.2017.07.001) Copyright © 2017 Terms and Conditions