Primary Resection of Kommerell Diverticulum and Left Subclavian Artery Transfer

Transcription

1 Primary Resection of Kommerell Diverticulum and Left Subclavian Artery Transfer Carl L. Backer, MD, Hyde M. Russell, MD, Katherine C. Wurlitzer, BA, Jeffrey C. Rastatter, MD, and Cynthia K. Rigsby, MD Cardiovascular-Thoracic Surgery, Otolaryngology, and Medical Imaging, Ann & Robert H. Lurie Children s Hospital of Chicago*; and the Departments of Surgery and Radiology, Northwestern University, Chicago, Illinois Background. A Kommerell diverticulum (KD) is an aneurysmal remnant of the dorsal fourth aortic arch. This can be an independent cause of tracheoesophageal compression. We previously reported resection of the KD with left subclavian artery transfer to the left carotid artery for recurrent symptoms in patients with a right aortic arch, left ligamentum, and retroesophageal left subclavian artery after prior ligamentum division. In 2001 we began resecting the KD and transferring the left subclavian artery to the left carotid artery in selected patients as a primary operation. Methods. From 2001 to 2011, 20 patients have had primary excision of a Kommerell diverticulum. Diagnosis was with computed tomographic scan (n 14) or magnetic resonance imaging (n 6) and bronchoscopy. Sixteen patients had a right aortic arch and 4 had a double aortic arch (right arch dominant). All patients were approached through a left thoracotomy. Fifteen patients had simultaneous division and reimplantation of the left subclavian artery into the left carotid artery. Results. Mean age at operation was years (range 1.5 to 29.1 years). Symptoms included cough, wheezing, stridor, dysphagia, and dyspnea on exertion. Selection criteria included KD greater than 1.5 times the size of the left subclavian artery and posterior pulsatile compression of the trachea on bronchoscopy. There were no complications related to subclavian artery transfer. No patient required a blood transfusion. No patient had a recurrent laryngeal nerve injury or chylothorax. The mean hospital stay was days. All patients had resolution of their preoperative airway and esophageal symptoms. Conclusions. In selected patients with a vascular ring we now recommend resection of the associated Kommerell diverticulum and transfer of the retroesophageal left subclavian artery to the left carotid artery as a primary procedure. This strategy requires comprehensive and precise preoperative imaging with either computed tomography or magnetic resonance imaging. (Ann Thorac Surg 2012;94:1612 8) 2012 by The Society of Thoracic Surgeons A Kommerell diverticulum is an embryologic remnant of the dorsal fourth aortic arch. It can occur with both right and left aortic arch configurations. In patients with a right aortic arch the Kommerell diverticulum often serves as the origin of the left subclavian artery. These patients also have a ligamentum arteriosum from the descending thoracic aorta adjacent to the Kommerell diverticulum connecting to the pulmonary artery. In 2002 we reported our experience with children undergoing resection of a Kommerell diverticulum because of recurrent symptoms after left ligamentum division [1]. The operation performed in those patients was Kommerell diverticulum resection (n 8) with left subclavian artery transfer to the left carotid artery (n 5). In that manuscript we also reported 1 patient, a 2.5-year-old Accepted for publication May 25, *Formerly Children s Memorial Hospital. Presented at the Poster Session of the Forty-eighth Annual Meeting of The Society of Thoracic Surgeons, Fort Lauderdale, FL, Jan 28 Feb 1, Address correspondence to Dr Backer, Division of Cardiovascular- Thoracic Surgery, Ann & Robert H. Lurie Children s Hospital of Chicago, 225 E Chicago Avenue, mc 22, Chicago, IL ; cbacker@luriechildrens.org. child, who had Kommerell diverticulum resection with left subclavian artery transfer as a primary procedure. The purpose of this current review is to summarize our results with primary resection of Kommerell diverticulum and left subclavian artery transfer in the vascular ring patient population. This review will summarize the clinical presentation, diagnostic evaluation techniques, surgical techniques, postoperative complications, and long-term outcome in patients undergoing primary resection of Kommerell diverticulum with left subclavian artery transfer. Patients and Methods This study was approved by the Institutional Review Board of Ann & Robert H. Lurie Children s Hospital of Chicago and Northwestern Memorial Hospital. Both waived the requirement of obtaining informed consent. Between 2001 and 2011, 20 patients underwent a primary operation for a vascular ring at which time a Kommerell diverticulum was excised. In 15 of those patients the left subclavian artery was transferred to the left carotid artery. In all cases the left ligamentum was ligated and divided. The presenting symptoms are shown in Table 1. Many patients had more than 1 symptom and no patient was asymptomatic by The Society of Thoracic Surgeons /$36.00 Published by Elsevier Inc

2 Ann Thorac Surg BACKER ET AL 2012;94: PRIMARY RESECTION OF KD AND LSA TRANSFER 1613 Table 1. Presenting Symptoms in Patients Undergoing Resection of a Kommerell Diverticulum a Presenting Symptom No. of Patients Dysphagia 5 Cough 7 Wheeze 7 Stridor 7 Recurrent upper respiratory tract infection 6 Shortness of breath with exercise 3 a These symptoms are not mutually exclusive and most patients had more than 1 symptom. No patient was asymptomatic. All patients received a preoperative echocardiogram to rule out associated significant congenital cardiac defects. Imaging of the aortic arch was by computed tomography (CT) in 14 patients and by magnetic resonance imaging (MRI) in 6 patients. The Kommerell diverticulum was considered a significant contribution to symptoms if the diameter was greater than 1.5 times the size of the left subclavian artery and was compressing the trachea posteriorly. Fifteen patients had origin of the left subclavian artery from the Kommerell diverticulum. One patient had anterior origin of the left subclavian artery with mirror-image branching of the right aortic arch. Four patients with a double aortic arch (right arch dominant) had an atretic left aortic arch with a significant Kommerell diverticulum and a left ligamentum. Prior to the thoracotomy, careful rigid bronchoscopic examination of the trachea is performed. Particular attention is paid to the distal posterior membranous trachea. A significant Kommerell diverticulum typically causes posterior pulsatile compression of the distal trachea. This is in addition to the right-sided anterior compression caused by the right aortic arch as it is pulled to the left by the ligamentum arteriosum. Many of these patients also have bronchomalacia and bronchial compression from the Kommerell diverticulum. In borderline patients where the diverticulum is less than 1.5 times the size of the left subclavian artery the bronchoscopy can be used as part of the evaluation to decide whether or not diverticulum resection will be required. If there is minimal posterior pulsatile compression, that would mitigate against Kommerell diverticulum resection. All operations were performed through a left thoracotomy. The chest was entered through the fourth intercostal space. Intraoperative monitoring included right radial arterial line and left hand pulse oximetry. In older patients arterial lines were placed in the lower extremity; in younger patients noninvasive blood pressure monitoring of the lower extremities was employed. Since 2008, cerebral oximetry has been used to monitor the right and left hemispheres during the procedure. After entering the chest, the lung is retracted anteriorly. The pleura overlying the left subclavian artery, Kommerell diverticulum, and descending thoracic aorta is sharply opened. The ligamentum arteriosum is dissected and encircled with a vessel loop. The Kommerell diverticulum is dissected back to its origin from the descending thoracic aorta. The ligamentum arteriosum is divided. This is either done between Potts ductus clamps with Prolene (Ethicon, Somerville, NJ) suture oversewing of the stumps or ligatures of 2.0 silk reinforced with Prolene suture, and then division. An important technical point here revolves again around the patient with a borderline sized Kommerell diverticulum. If there is excellent separation of the stumps of the ligamentum after division ( 1.5 to 2.0 cm), this indicates to us a probable successful division of the vascular ring with attendant improvement in symptoms, potentially leading to resolution of the patient s symptoms. In the majority of our cases, however, the ligamentum stumps would only separate 0.5 to 1.0 cm, which we did not believe was adequate to relieve the compression on the trachea and esophagus. The left common carotid artery is identified in a plane that is anterior to the recurrent laryngeal nerve as it passes in the tracheoesophageal groove and posterior to the vagus nerve. The left common carotid artery was encircled with a vessel loop. The subclavian artery is marked at its most anterior aspect with a fine Prolene suture to help the orientation of the eventual transfer. Patients were then systemically heparinized with intravenous heparin (100 units/kg). The origin of the base of the Kommerell diverticulum is occluded with a Satinsky clamp. When this clamp is placed there should be careful evaluation of the blood pressure in the lower extremity to ensure that a neo-coarctation is not created. The left subclavian artery is controlled with a small vascular hemoclip. The subclavian artery is transected at its origin from the Kommerell diverticulum. The Kommerell diverticulum is resected within the confines of the clamp on the descending thoracic aorta leaving a 4 to 5 mm cuff to place sutures. The opening in the descending thoracic aorta is closed with a running Prolene suture placed in 2 layers, the first being a mattress suture. The suture line is then reinforced with interrupted Prolene horizontal mattress sutures. The clamp on the descending thoracic aorta is released. The left common carotid artery is then occluded with a Castañeda clamp. Cerebral oximetry is monitored for 1 minute prior to incising the carotid artery. No patient has had a drop in the near-infrared spectroscopy. If they did we would take measures to increase cerebral blood flow. The left subclavian artery is anastomosed to the carotid artery with either a 6.0 or 7.0 running Prolene suture. Air is removed from the suture line in the usual fashion and the clamps are released. In all cases the mediastinal pleura is left open. For the past 5 years we have been using Blake drains (Ethicon) to drain the chest rather than hard plastic chest tubes. The chest is closed in layers and the patient is extubated in the operating room. Patients having left subclavian artery transfer were kept on aspirin for 3 months. The age at operation ranged from 1.5 years to 29.1 years. The mean age was years; a median of 8 years. The clamp time on the carotid artery ranged from 13 to 29 minutes with a mean of 21 5 minutes; with a median of 21 minutes. The size of the Kommerell diverticulum ranged from 1 1cmto2 3 cm, with a median

3 1614 BACKER ET AL Ann Thorac Surg PRIMARY RESECTION OF KD AND LSA TRANSFER 2012;94: diverticulum size of cm. The postoperative hospital stay ranged from 2 to 7 days with a mean stay of days. The median hospital stay was 4 days. Follow-up is complete in all patients and includes initial postoperative surgery visit and referring clinician records. Follow-up ranges from 0.5 to 10 years, mean follow-up is 4 years. Results There was no operative or late mortality. No patient required a blood transfusion. No patient had a recurrent laryngeal nerve injury. There were no complications related to the subclavian artery transfer. All patients have had resolution of their preoperative respiratory and swallowing symptoms. In most patients there was an initial significant improvement followed by complete resolution of symptoms over the next 3 to 6 months. All patients have had postoperative imaging of the left subclavian artery anastomosis. This has been done by echocardiogram, repeat CT imaging, or MRI. All anastomoses are patent. All patients have a palpable left radial pulse. No patient has a neo-coarctation. This group of patients should be put in context of our overall vascular ring population. Since 1946 we have operated on 140 patients with a right aortic arch (mean age 8 months) and 139 patients with a double aortic arch (mean age 10 months). We have performed a Kommerell diverticulum resection as a second stage operation in 14 patients after a prior ligamentum division (13 operated on elsewhere). Mean age in this group was years; median age 9.2 years. Comment Right aortic arch with left ligamentum can be associated with a Kommerell diverticulum. Less commonly a Kommerell diverticulum can occur with a double aortic arch. Patients with a right aortic arch have 2 types of branching of the brachiocephalic vessels. In 65% of these patients there is a retroesophageal origin of the left subclavian artery. In 35% of these patients there is mirror-image branching with a left brachiocephalic artery [2]. In both cases a Kommerell diverticulum may be present. It is more frequent in patients with a retroesophageal origin of the left subclavian artery. The Kommerell diverticulum is a remnant of the left fourth aortic arch. This phrase was first coined by B. Kommerell in a German radiology journal in 1936 [3]. van Son and colleagues [4] have written a beautiful historical perspective of the life of Burkhard F. Kommerell and his role in the naming of Kommerell as an eponym. Kommerell described a patient with a left aortic arch and aberrant origin of the right subclavian artery from a diverticulum of the descending aorta. He was the first to postulate that the embryologic origin of this diverticulum was the dorsal right fourth aortic arch. In patients with a right aortic arch the diverticulum is an embryologic remnant of the dorsal left aortic arch. A Kommerell diverticulum can be an independent cause of compression of the trachea and esophagus in patients with and without a vascular ring. In particular, there are many case reports of adults presenting with dysphagia or hoarseness from recurrent laryngeal nerve traction with a left aortic arch and a large Kommerell diverticulum serving as the origin of a right subclavian artery [5, 6]. We first became aware of the potential technique of resecting the Kommerell diverticulum and transferring the left subclavian artery to the left carotid artery in the chapter by Langlois and colleagues in the book, Pediatric Thoracic Surgery [7]. In that textbook, the authors recommended that if a Kommerell diverticulum existed it should be excised between 2 clamps. They also recommended dividing the left subclavian artery and reimplanting it into the left common carotid artery. The number of patients treated in this manner was not stated in this chapter. The first 7 patients upon whom we performed a Kommerell diverticulum resection and transfer of the left subclavian artery to the left carotid artery were performed as a reoperation after a prior ligamentum division [1]. These patients all presented with recurrence of their respiratory or swallowing symptoms after initial resolution after vascular ring (ligamentum) division. That experience encouraged us to perform this procedure as a primary operation for the first time in That patient was a 2.5-year-old child noted to have a seal bark cough shortly after birth. She had had intermittent difficulty with noisy breathing and an extremely hoarse cough whenever she had an upper respiratory tract infection. After an episode of pneumonia she had magnetic resonance imaging of her chest that demonstrated a right aortic arch, retroesophageal left subclavian artery, cm Kommerell diverticulum, and a left ligamentum arteriosum. She underwent ligation and division of the ligamentum, resection of the Kommerell diverticulum, and reimplantation of the left subclavian artery into the left carotid artery as a primary procedure. She had no postoperative complications and was discharged from the hospital on the third postoperative day. This initial success led us to be more proactive in our surgical approach to these patients. It is our impression that there are several factors combining to cause esophageal and tracheal compression in these patients. As mentioned earlier, the Kommerell diverticulum in and of itself occupies space in the mediastinum and can posteriorly compress the trachea and esophagus. An example of a CT image of such a patient is shown in Figure 1. Note the spine posterior to the diverticulum which prevents posterior movement. A second mechanism is the sling-like effect of the left subclavian artery pulling the right aortic arch to the left. This pulls the right aortic arch against the trachea and esophagus. A third mechanism is the left subclavian artery acting as a bowstring between the descending thoracic aorta on the right side and the arm on the left side, and this alone can be enough to compress the esophagus posteriorly. This was demonstrated to us by a patient who had a diverticulum resection but then required a reoperation for transfer of the left subclavian

4 Ann Thorac Surg BACKER ET AL 2012;94: PRIMARY RESECTION OF KD AND LSA TRANSFER 1615 Fig 1. Computed tomographic axial image of a 7-year-old patient with a right aortic arch (R) and a significant Kommerell diverticulum (KD), which is the origin of the left subclavian artery. The diverticulum is shown occupying the space immediately posterior to the trachea. The esophagus is not visible because it is severely compressed by the diverticulum. artery 12 years later. These 3 mechanisms are all corrected by resection of the diverticulum and transfer of the left subclavian artery. The posterior pulsatile compression of the trachea from the Kommerell diverticulum is removed, and the sling-like effect of the pull of the left subclavian artery on the right arch is removed. A follow-up CT scan of the same patient shown in the previous figure is shown in Figure 2. Our imaging of these patients has been primarily with CT scan but we have also used MRI. We discussed our preference for CT imaging in 2005 [8]. Computed tomography gives us clear images not only of the vascular structures but also the trachea. The CT scans can also be done much more quickly than an MRI (avoiding intubation and anesthesia). Our current CT scan allows for acquisition of high-quality images in 50 to 100 ms, with doses of radiation ranging from 0.05 to 0.8 msv [9]. However, MRI images have also improved and are quite good in older cooperative patients. An example of a preoperative MRI with three-dimensional reconstruction Fig 3. Magnetic resonance imaging three-dimensional reconstruction of a patient with a right aortic arch and the Kommerell diverticulum (KD) serving as a source of blood supply to a retroesophageal left subclavian artery (LSA). This is a posterior view. Fig 2. Post-repair image of patient in Figure 1. Computed tomographic axial image demonstrates that there is now no posterior occupation of space by the Kommerell diverticulum or the subclavian artery. The trachea is completely free posteriorly. The right aortic arch (R) has been released to move slightly to the right. The esophagus (E) is now visible as a small second opening below the trachea. is shown in Figure 3. A postoperative CT image of a similar patient after Kommerell diverticulum resection and left subclavian artery transfer is shown in Figure 4. Our definition of a significant Kommerell diverticulum is a widening of the base of the subclavian artery that is more than 1.5 the size of the distal subclavian artery. In the majority of our patients the subclavian artery was between 4 and 6 mm in diameter. Hence, a Kommerell diverticulum that is greater than 1 cm in diameter would be significant. The great majority of the Kommerell diverticulum in this series was at least 1 cm and more frequently 1.5 cm to 2 cm in diameter. There were 5 patients who had a Kommerell diverticulum resection for whom we did not transfer the left subclavian artery to the left carotid artery. One patient had a right aortic arch with anterior origin of the left subclavian artery (mirror-image branching) and did not

5 1616 BACKER ET AL Ann Thorac Surg PRIMARY RESECTION OF KD AND LSA TRANSFER 2012;94: Fig 4. Computed tomographic image. The left subclavian artery has been successfully transferred to the left carotid artery (white arrowhead). The black arrow head shows that the site of a Kommerell diverticulum is now completely free and the aorta appears smooth where the Kommerell diverticulum was located. require subclavian transfer. Four patients had a double aortic arch (right arch dominant) with an atretic left aortic arch and a left ligamentum (Fig 5). These patients had division of the left aortic arch and left ligamentum along with resection of a significant Kommerell diverticulum at the time of vascular ring surgery. One interesting aspect of the patients undergoing a primary Kommerell diverticulum resection is that they are all substantially older than other vascular ring patients in our series. Our mean age in the recent era for double aortic arch is 2.75 years and for right aortic arch is 3.2 years (1992 to 2011). The mean age of the primary Kommerell diverticulum resection patients in our series was 9 years. The mean age of a patient having Kommerell diverticulum resection as a secondary operation was 13 years. One might speculate that the Kommerell diverticulum grows over time and contributes to this discrepancy. We do have 1 patient, however, who was 1.5 years of age at operation; therefore, enlargement over time does not tell the entire story. Another early advocate of excision of a Kommerell diverticulum was the group from Johns Hopkins [10]. Chun and colleagues reported a patient who had persistent severe symptoms after ligamentum division and underwent subsequent excision of an aortic diverticulum with complete relief of symptoms. Ota and colleagues [11] reported 6 patients undergoing resection of a Kommerell diverticulum. Four of those patients had a right aortic arch and aberrant left subclavian artery. Malas and colleagues [12] recently reported a patient who had dyspnea lusoria from a Kommerell diverticulum. This patient had compression of the pulmonary artery by a Kommerell diverticulum. Successful repair of this was performed through a left thoracotomy using an interposition graft to replace the aneurysmal portion of the aorta. Shinkawa and colleagues from Arkansas Children s Hospital [13] recently reported 10 patients having primary translocation of left subclavian artery and Kommerell diverticulum resection. They compared these patients to 8 who only had ligamentum division. All patients in the Kommerell diverticulum resection group became asymptomatic compared with 5 of 8 in the ligamentum division group; interestingly, the mean age in their series was 1.8 years. Some surgeons have advocated resecting the Kommerell diverticulum and simply ligating the left subclavian artery and not reimplanting it. We hesitate to do this for several reasons. There is a small but well-known incidence of hand ischemia after ligation of the subclavian artery for either a modified Blalock-Taussig shunt or subclavian flap repair of coarctation of the aorta [14, 15]. Also, if the left subclavian artery is ligated these patients can develop late subclavian steal syndrome. Ciocca and colleagues [16] described a 45-year-old who at the age of 18 months had ligation of a subclavian artery and division of the ligamentum for treatment of a right arch with left ligamentum. That patient developed symptomatic subclavian steal syndrome and required a carotid to subclavian bypass. Jung and colleagues [17] also recommended reimplantation of the subclavian artery to avoid the development of subclavian steal syndrome later in life. Fig 5. Computed tomographic image. Three-dimensional reconstruction of an 8-year-old patient with a double aortic arch, right arch (R) dominant, atretic left arch, left ligamentum, and large symptomatic Kommerell diverticulum (KD). The posterior view shows the KD projecting like a thumb from the descending aorta.

6 Ann Thorac Surg BACKER ET AL 2012;94: PRIMARY RESECTION OF KD AND LSA TRANSFER 1617 Another reason to excise the Kommerell diverticulum is that it can be a potential source of aortic dissection. Braunberger and colleagues [18] described a 30-year-old patient who had a chronic aortic dissection. The entrance tear was within a Kommerell diverticulum. Another unusual complication that was reported by Fisher and colleagues [19] was of a Kommerell diverticulum with rupture of the aneurysm. A Kommerell diverticulum is a structure in patients with a right aortic arch or double aortic arch that may independently cause tracheoesophageal compression. We previously resected this only in patients who had prior division of the ligamentum and then developed recurrent airway or swallowing symptoms. Our current recommendation is that for selected patients with a significant Kommerell diverticulum ( 1.5 times the size of the left subclavian artery), the diverticulum should be resected at the time of ligamentum division. For the majority of patients who also have origin of the retroesophageal left subclavian artery from the Kommerell diverticulum that subclavian artery should be transferred to the left carotid artery as an initial procedure. We have shown this to be a safe and very effective therapy for this select group of patients. This management strategy is based on our principle of obtaining advanced imaging in all patients with vascular rings as we have previously described. The use of this approach should avoid the need for a second operation in patients with this constellation of congenital abnormalities. References 1. Backer CL, Hillman N, Mavroudis C, Holinger LD. Resection of Kommerell s diverticulum and left subclavian artery transfer for recurrent symptoms after vascular ring division. Eur J Cardiothorac Surg 2002;22: Felson B. Palayew MJ. The two types of right aortic arch. Radiology 1963:81: Kommerell B. Verlagerung des osophagus durch eine abnorm verlaufende arteria subclavia dextra (arteria lusoria). Fortschr Geb Rontgenstr 1936;54: van Son JAM, Konstantinov IE. Burckhard F. Kommerell and Kommerell s diverticulum. Tex Heart Inst J 2002;29: Kiernan PD, Dearani J, Byrne WD, et al. Aneurysm of an aberrant right subclavian artery: case report and review of the literature. Mayo Clin Proc 1993;68: Campbell CF. Repair of an aneurysm of an aberrant retroesophageal right subclavian artery arising from Kommerell s diverticulum. J Thorac Cardiovasc Surg 1971;62: Langlois J. Binet JP, DeBrux JL, Hvass U, Planché C. Aortic arch anomalies. In: Fallis JC, Filler RM, Lemoine G, eds. Pediatric thoracic surgery. New York: Elsevier; 1991: Backer CL, Mavroudis C, Rigsby CK, Holinger LD. Trends in vascular ring surgery. J Thorac Cardiovasc Surg 2005;129: Paul JF, Rohnean A, Elfassy E, Sigal-Cinqualbre A. Radiation dose for thoracic and coronary step-and-shoot CT using a 128-slice dual-source machine in infants and small children with congenital heart disease. Pediatr Radiol 2011;41: Chun K, Colombani PM, Dudgeon DL, Haller JA Jr. Diagnosis and management of congenital vascular rings: a 22- year experience. Ann Thorac Surg 1992;53: Ota T, Okada K, Takanashi S, Yamamoto S, Okita Y. Surgical treatment of Kommerell s diverticulum. J Thorac Cardiovasc Surg 2006;131: Malas MB, Barr ML, Starnes VA, Shapiro S, Palmer S, Schwartz DS. Dyspnea lusoria: compression of the pulmonary artery by a Kommerell s diverticulum. Ann Thorac Surg 2002;73: Shinkawa T, Greenberg SB, Jaquiss RD, Imamura M. Primary translocation of aberrant left subclavian artery for children with symptomatic vascular ring. Ann Thorac Surg 2012;93: Geiss D, Williams WG, Lindsay WK, Rowe RD. Upper extremity gangrene: a complication of subclavian artery division. Ann Thorac Surg 1980;30: Wells WJ, Castro LJ. Arm ischemia after subclavian flap angioplasty: repair by carotid-subclavian bypass. Ann Thorac Surg 2000;69: Ciocca RG, Wilkerson DK, Madson DL, Andrew CT, Graham AM. Symptomatic subclavian steal syndrome four decades after operation for dysphagia lusoria. Ann Vasc Surg 1995;9: Jung JY, Almond CH, Saab SB, Lababidi Z. Surgical repair of right aortic arch with aberrant left subclavian artery and left ligamentum arteriosum. J Thorac Cardiovasc Surg 1978;75: Braunberger E, Mercier F, Fornes P, Julia PL, Fabiani J-N. Aortic dissection of Kommerell s diverticulum in Marfan s syndrome. Ann Thorac Surg 1999;67: Fisher RG, Whigham CJ, Trinh C. Diverticula of Kommerell and aberrant subclavian arteries complicated by aneurysms. Cardiovasc Intervent Radiol 2005;28: INVITED COMMENTARY Backer and colleagues [1] have described a group of symptomatic patients with a vascular ring anomaly (predominately right aortic arch with a retroesophageal left subclavian artery) associated with an enlarged Kommerell s diverticulum (KD) [1]. They have recommended that those with a KD more than 1.5 times the size of the left subclavian artery (LSA) undergo resection of the KD and LSA transfer to the left carotid. At issue is how this report will affect the future surgical management of patients presenting with a vascular ring anomaly. Careful analysis of the demographics of patients included in this study shows that they are quite different from the usual vascular ring population. The usual patient presents at less than 1 year, a finding collaborated by the author s own vast experience wherein the mean age among 140 patients operated with a right aortic arch vascular ring was 8 months; it was 10 months for those with a double aortic arch. In contrast, the mean age in this series was 9.1 years. As the authors have noted, this raises a question as to whether the prolonged presence of a vascular ring may predispose to enlargement of a KD. Further evidence that this may be the case comes from the finding that among the 140 right aortic arch vascular ring operations performed by the group at Children s Memorial, only one has returned with a symptomatic enlarged KD. Although we do not know whether there are others with KD enlargement, if this is the case they have apparently remained asymptomatic by The Society of Thoracic Surgeons /$36.00 Published by Elsevier Inc