Repair of Kommerell's Diverticulum and Aberrant Subclavian Arteries: Classification of the Five Groups in Declining Frequency and Their Operative Approaches

Abstract

Aberrant subclavian arteries are a result of unusual involution of the branchial arches resulting in persistent arteries that can cause tracheal or esophageal compression. Many are incidental findings but may be associated with dysphagia (dysphagia lusus naturae, Latin for “jest of nature”), a long history of asthma treatment for wheezing, or more uncommonly, aneurysms or aortic dissection. There are 5 basic approaches for repair discussed herein, determined by which subclavian artery is involved and where the aortic arch and descending thoracic aorta lie, as well as the size of the latter, classified as Groups A to E, in order of frequency. These include: A: Aberrant RSCA and left arch; B: Aberrant LSCA and right arch; C: Aberrant RSCA, no significant Kommerell's and descending aneurysm; D: Aberrant LSCA and right-sided arch but compression from a vascular ring; and E: Aberrant RSCA and extensive arch and descending aneurysm. Aberrant subclavian arteries are a result of unusual involution of the branchial arches resulting in persistent arteries that can cause tracheal or esophageal compression. Many are incidental findings but may be associated with dysphagia (dysphagia lusus naturae, Latin for “jest of nature”), a long history of asthma treatment for wheezing, or more uncommonly, aneurysms or aortic dissection. There are 5 basic approaches for repair discussed herein, determined by which subclavian artery is involved and where the aortic arch and descending thoracic aorta lie, as well as the size of the latter, classified as Groups A to E, in order of frequency. These include: A: Aberrant RSCA and left arch; B: Aberrant LSCA and right arch; C: Aberrant RSCA, no significant Kommerell's and descending aneurysm; D: Aberrant LSCA and right-sided arch but compression from a vascular ring; and E: Aberrant RSCA and extensive arch and descending aneurysm. Central MessageAberrant subclavian arteries are unusual, and can cause tracheal or esophageal compression. Five basic approaches for repair are discussed, grouped in order of frequency. Aberrant subclavian arteries are unusual, and can cause tracheal or esophageal compression. Five basic approaches for repair are discussed, grouped in order of frequency. The normal involution of the branchial arches results in 2 subclavian arteries and carotid arteries, but where the arteries attach to the persistent arch and where it lies can vary.1Svensson LG Crawford ES. Abnormal development of the aortic arch.in: Svensson LG Crawford ES Cardiovascular and Vascular Disease of the Aorta. WB Saunders, Philadelphia1997: 160-173Google Scholar The most common type of aberrant artery is a right subclavian artery (RSCA) that comes off the distal aortic arch and proximal descending aorta and runs behind the trachea and esophagus; hence, potential dysphagia (dysphagia lusus naturae, Latin for “jest of nature”) may occur, particularly if Kommerell's diverticulum, the proximal part of the RSCA, dilates, including with or without a descending aortic aneurysm formation (Group A; see Fig. 1 and Table 1). Wheezing, checked by pulmonary function tests, is less common but dissection or rupture may occur. Routine preoperative tests are pulmonary function tests, computed tomography, echocardiography, and cardiac catheterization. Esophageal studies and bronchoscopy are also options, based on symptoms. Note on computed tomography scans, a fluid bubble is often found above the compressed esophagus. Alternatively, the arch is on the right side with an aberrant left subclavian artery (LSCA) (Group B; see Fig. 2) Less commonly, some patients have an aberrant RSCA and a descending aortic aneurysm (Group C; see Fig. 3) For Group D: Aberrant LSCA and right-sided arch with vascular compression ring (see Fig. 4). Aberrant RSCA with large thoracic aneurysmal formation can, however, be extensive (Group E; see Fig. 7).1Svensson LG Crawford ES. Abnormal development of the aortic arch.in: Svensson LG Crawford ES Cardiovascular and Vascular Disease of the Aorta. WB Saunders, Philadelphia1997: 160-173Google Scholar, 2Albacker TB Roselli EE Pettersson GB et al.Surgical management of right aortic arch with tailored surgical approach.J Card Surg. 2012; 27: 511-517Crossref PubMed Scopus (2) Google Scholar, 3Bhandary SP Papadimos TJ Svensson LG et al.Anesthetic management of the resection of a Kommerell's diverticulum.J Cardiothorac Vasc Anesth. 2015; 29: 142-145Abstract Full Text Full Text PDF PubMed Scopus (3) Google Scholar, 4Hussain ST Tong MZ Pettersson GB et al.Remnant of repaired right aortic arch stump as a rare cause of recurrent strokes: the eyes see only what the mind knows!.J Thorac Cardiovasc Surg. 2014; 148: e207-e208Abstract Full Text Full Text PDF PubMed Google Scholar, 5Idrees J Keshavamurthy S Subramanian S et al.Hybrid repair of Kommerell diverticulum.J Thorac Cardiovasc Surg. 2014; 147: 973-976Abstract Full Text Full Text PDF PubMed Scopus (74) Google Scholar, 6Lee R Maughan RE Svensson LG. Elephant trunk reconstruction for aberrant right subclavian and aortic aneurysm.Ann Thorac Surg. 1997; 64: 547-548Abstract Full Text PDF PubMed Scopus (12) Google ScholarTable 1Most Common Types of Aberrant Subclavian Arteries, Grouped by Characteristics, and Associated Variants of Kommerell's Diverticulum Variants (Figures 1-7)GroupCharacteristicsGroup ALeft-sided aorta with aberrant right subclavian artery (RSCA) and large Kommerell's diverticulum (Fig. 1)Group BFelson Palayew Type II—right-sided arch with aberrant left subclavian artery (LSCA) (Fig. 2)Group CLarge left-sided aneurysm with aberrant RSCA without compression (Fig. 3)Group DFelson Palayew Type I—right-sided arch with constrictive vascular ring (Fig. 4)Group EAberrant RSCA and extensive arch and descending aneurysm (Fig. 7) Open table in a new tab Figure 2Group B: Right-sided arch with aberrant left subclavian artery (LSCA). Reprinted with permission, Cleveland Clinic Foundation ©2022. All Rights Reserved. (Color version of figure is available online at www.optechtcs.com.)View Large Image Figure ViewerDownload Hi-res image Download (PPT)Figure 3Group C: Left-sided arch with large aneurysm and no compression from aberrant RSCA. Reprinted with permission, Cleveland Clinic Foundation ©2022. All Rights Reserved. (Color version of figure is available online at www.optechtcs.com.)View Large Image Figure ViewerDownload Hi-res image Download (PPT)Figure 4Right-sided arch with large left aneurysm with an LSCA from the apex of an aneurysm extending up into the LSCA. Reprinted with permission, Cleveland Clinic Foundation ©2022. All Rights Reserved. (Color version of figure is available online at www.optechtcs.com.)View Large Image Figure ViewerDownload Hi-res image Download (PPT) The other less common types of subclavian arteries with the aberrant LSCA coming off the right-sided arches (see Fig. 2) fall into 2 basic types with variability: Felson Palayew Types I and II.7Vinnakota A Idrees JJ Rosinski BF et al.Outcomes of repair of Kommerell diverticulum.Ann Thorac Surg. 2019; 108: 1745-1750Abstract Full Text Full Text PDF PubMed Scopus (22) Google Scholar,8Felson B Palayew MJ. The two types of right aortic arch.Radiology. 1963; 81: 745-759Crossref PubMed Scopus (109) Google Scholar Type II is more common, involving a right-sided arch with an aberrant LSCA running behind the esophagus, sometimes between the esophagus and trachea (Group B; see Fig. 2). For Felson Palayew Type I, there is a right-sided arch, but the take-off of the LSCA can be variable and even may come off the distal right-sided arch or from near the origin of the left common carotid artery (LCCA) (Group D), creating a constrictive vascular ring.3Bhandary SP Papadimos TJ Svensson LG et al.Anesthetic management of the resection of a Kommerell's diverticulum.J Cardiothorac Vasc Anesth. 2015; 29: 142-145Abstract Full Text Full Text PDF PubMed Scopus (3) Google Scholar The 5 groups are discussed and include most common presentations and operative approaches. In declining order of indication for surgery, these are dysphagia, wheezing, dyspnea, aneurysm, dissection, rupture, or very rarely, a mycotic aneurysm. The most common variant is the easiest to treat. Aberrant RSCA mobilization and oversewing of the RSCA and descending thoracic aorta (DTA) replacement is initiated through the left chest. The distal arch, RSCA, left subclavian arteries (LSCA), and DTA are mobilized freely, while taking care to preserve the left recurrent nerve and protect the esophagus, which can be quite thin-walled and adhered to the trachea and RSCA. The RSCA needs to be followed up to the right side of the esophagus. Depending on the size of the aorta and Kommerell's diverticulum, a decision must be made regarding type of bypass needed, if at all. Some patients only require division of the RSCA; however, this needs to be completed so that the RSCA can be oversewn, tied, and pushed to the right of the esophagus to ensure complete decompression. If the DTA is aneurysmal, a tube graft is sewn into the aortic position usually with only atriofemoral bypass, cerebrospinal fluid (CSF) drainage, and intrathecal papaverine (Fig. 5). The management of the distal RSCA is variable. A bypass can be done from the carotid either before or after left thoracotomy, but the RSCA proximal to the anastomosis must be oversewn, preferably proximal to the internal mammary artery to fully decompress the stump. The top of the illustration in Figure 1 shows the anatomy with the RSCA coming off the distal arch and compressing the esophagus. The next illustrations show insertion of a DTA graft (Fig. 5), decompression of the esophagus (Fig. 6), oversewing of the RSCA stump, and an anastomosis of the RSCA to the right carotid artery (Fig. 6).Figure 6Replaced aorta and RSCA decompression. Reprinted with permission, Cleveland Clinic Foundation ©2022. All Rights Reserved. (Color version of figure is available online at www.optechtcs.com.)View Large Image Figure ViewerDownload Hi-res image Download (PPT)Figure 7Group E: Extensive aneurysm requiring elephant trunk procedure and second stage bypass of aberrant RSCA. Reprinted with permission, Cleveland Clinic Foundation ©2022. All Rights Reserved. (Color version of figure is available online at www.optechtcs.com.)View Large Image Figure ViewerDownload Hi-res image Download (PPT) These patients should be approached with some caution because the aorta is more fragile and easily tears or dissects. The chest is opened in the fourth intercostal space on the right side. With this incision, it is easy to cannulate the ascending aorta. The method should begin with right-sided arch and aberrant LSCA mobilization and oversewing of the LSCA and DTA replacement followed with the posterior aortic wall anastomosis strengthened with 5/0 horizontal mattress sutures. Also, moving the LSCA stump to the other side or left side of the esophagus or trachea can be more difficult, but if performed carefully, it can be done before cardiopulmonary bypass, depending on the size of the diverticulum. Needless to point out, if the LSCA runs between the trachea and esophagus, extra caution is required to avoid injuring them. An intercostal muscle flap can be swung over to further protect the trachea and esophagus after repair. Note also the recurrent nerve wraps around the aorta, which must be protected. The azygos vein is also divided and securely tied to improve exposure. Once the aorta and arteries are mobilized, I recommend routine cardiopulmonary bypass with a cooler in case circulatory arrest is necessary, followed by routine replacement of the DTA. Cardioplegia and cardiac arrest are usually not required, except for circulatory arrest. Once the patient is on pump, the distal arch is clamped and the DTA more distally near the diaphragm. If there is concern for longer clamp time, then moderate cooling and distal perfusion, best femoral and not aortic, is an option. The aorta is opened, and the previously mobilized LSCA stump is oversewn and tied off—if not already mobilized—and pushed to the left side. Sometimes there is an atrophied attachment to the Kommerell's diverticulum extending caudally that needs to be divided. The proximal anastomosis is then completed with a 4/0 or 5/0 polypropylene suture and then tested under low flow; the posterior wall is then strengthened with delicately placed 5/0 horizontal mattress pledgeted sutures. It is then tested at higher pressures, the graft clamped, and the distal anastomosis performed. Before completing the distal anastomosis, the internal suture line is strengthened with 5/0 horizontal mattress internal pledgeted sutures. It is important that for these operations, at least a 22-mm graft is used for larger males and a 20-mm for females, even though the aorta may appear to be smaller. The top of the illustration shows anatomy and the patient cannulated for cardiopulmonary bypass. The lower illustration shows the repair with the LSCA oversewn with carotid bypass. An interposition graft is in place. This can be done separately before or after the right thoracotomy repair. The recommended sequence is: tie off the azygous, cannulate, mobilize the aorta and LSCA, tie off the LSCA, go on pump, clamp the distal arch, clamp the descending aorta, and transect the distal arch and distal DTA. These patients with aneurysmal left-sided DTA but no significant associated RSCA symptoms or compression of the esophagus or trachea may undergo stent grafting as an option; however, recurrence may occur as we previously described,7Vinnakota A Idrees JJ Rosinski BF et al.Outcomes of repair of Kommerell diverticulum.Ann Thorac Surg. 2019; 108: 1745-1750Abstract Full Text Full Text PDF PubMed Scopus (22) Google Scholar and symptomatic compression may not be relieved. The problem with stenting is that if the stent is placed for a symptomatic diverticulum, the esophagus and trachea may not be decompressed, and thus without relief of symptoms. Hence, this approach is not usually used for an enlarged Kommerell's diverticulum. The illustration in Fig. 3 shows an aneurysm DTA with a stent without an associated enlarged Kommerell's diverticulum and no compression of the esophagus or trachea. Patients with a right-sided arch and left chest DTA, including a constrictor ring (aorta, atrophied ductus, nerves, LSCA)1Svensson LG Crawford ES. Abnormal development of the aortic arch.in: Svensson LG Crawford ES Cardiovascular and Vascular Disease of the Aorta. WB Saunders, Philadelphia1997: 160-173Google Scholar,9Robinson BL Nadolny EM Entrup MH et al.Management of right-sided aortic aneurysms.Ann Thorac Surg. 2001; 72: 1764-1765Abstract Full Text Full Text PDF PubMed Scopus (23) Google Scholar often require deep hypothermia and circulatory arrest through the left chest because the DTA aneurysm arises from the right-sided arch in the right chest. Hence, an anastomosis needs to be done to the distal arch in the right chest to a fragile aorta. While this may appear difficult, if the aorta is significantly aneurysmal and then the anastomosis is done inside the aorta (inclusion technique) and strengthened with pledgeted horizontal mattress sutures, this usually is not too much of a problem, even if the vertebral bodies hamper exposure. The other option is oversewing the non-aneurysmal stump of the arch and doing an ascending aorta to distal DTA bypass and attaching the aberrant LSCA with or without a graft to the DTA graft, but is not recommended for an aneurysmal stump. The pulmonary artery can be divided to get better exposure of the ascending aorta and then repaired again. We have used both options. The right-sided anastomosis in an aneurysm is trickier but probably safer in the long term than the easier ascending aorta to DTA bypass (oversewn aortic stumps have a high risk of rupturing over time). The band is decompressed, particularly to the patent ductus arteriosus remnant, and an ascending aorta to DTA bypass has been completed with hook-up of the LSCA and oversewing of the aortic stump. Figure 4 depicts a patient who had a right-sided arch and then an aneurysmal LSCA coming off the apex of the aneurysm, and a tight vascular ring constricting the mediastinum. This was dealt with by releasing the ring and placing an ascending-to-distal aortic graft, reattaching the LSCA, and oversewing the right arch stump. We left the aorta on the right in place to perfuse the intercostal arteries. Many years later, this patient is still alive and is doing well. In 526 elephant trunk procedures,10Svensson LG Rushing GD Sepulveda Valenzuela E et al.Modifications, classification, and outcomes of elephant-trunk procedures.Ann Thorac Surg. 2013; 96: 548-558Abstract Full Text Full Text PDF PubMed Scopus (39) Google Scholar I am aware of only 2 patients who presented with extensive aneurysmal disease and aberrant RSCA in that series. In our more recent series, however, many more had elephant trunk procedures (n = 19).7Vinnakota A Idrees JJ Rosinski BF et al.Outcomes of repair of Kommerell diverticulum.Ann Thorac Surg. 2019; 108: 1745-1750Abstract Full Text Full Text PDF PubMed Scopus (22) Google Scholar Two-stage elephant trunk procedures with aberrant RSCA management are similar to any elephant trunk procedure in that the patient is put on a pump via the RSCA artery and the anastomosis is completed proximal or distal to the LSCA and RSCA ostia, but the patient is reperfused antegrade via a side graft on the arch, as originally described. Our team has subsequently and more liberally used the LSCA for pump perfusion. The second stage is completed if necessary, either with a bypass to the RSCA if not enlarged, or oversewn, as described above, if causing compressive symptoms. The illustration shows the repair of an extensive aneurysm of the aorta with aberrant RSCA. The elephant trunk has been anastomosed between the LSCA and RSCA and at the second stage of the operation, an interposition graft was placed to the RSCA, since there was no compression. In our series of 152 patients with aberrant subclavian arteries, 87 did not require surgery, and survival was 100% in the 65 patients who required surgery, mostly owing to symptoms.7Vinnakota A Idrees JJ Rosinski BF et al.Outcomes of repair of Kommerell diverticulum.Ann Thorac Surg. 2019; 108: 1745-1750Abstract Full Text Full Text PDF PubMed Scopus (22) Google Scholar None of the open surgical repair patients had residual symptoms except one, who had an aortopexy. Of the 10 stented patients, 3 required reintervention and 4 died, P = 0.001, versus open repairs. Of the unoperated patients, 1 of 2 who refused surgery died of aortic rupture; the others did not develop symptoms, nor did their eventual causes of death relate to the aorta. When to operate on an asymptomatic aneurysmal Kommerell's diverticulum is somewhat uncertain, but if the base at the aorta is larger than 2.5 cm and the takeoff at the aorta is more than 5.0 cm, it would seem reasonable to operate. Although tissue can be fragile, with appropriate care, surgery can be successful; only 1 patient had residual symptoms following aortopexy, which is not recommended. It must, however, be stressed that the esophagus and trachea must be completely decompressed and the aberrant compressing artery removed. We have seen other strange anatomic variants of the arch, like 4 or 5 greater arteries coming off the arch, but these are not included here, as they typically do not have Kommerell's diverticulum or compressive symptoms of the esophagus or trachea. Patients are typically very grateful for symptom relief, often misdiagnosed for years.