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The Ascending Thoracic Aorta Stages a Vanishing Act?
DIAGNOSTIC DILEMMAS
The Ascending Thoracic Aorta Stages a Vanishing Act? Paul S. Pagel, MD, PhD,* Robert A. Biechler, MD,* and G. Hossein Almassi, MD†
A
N 85-YEAR-OLD, 101-kg, 168-cm tall man was admitted to the institution for evaluation of syncope, exertional chest pain radiating to his left shoulder, progressive dyspnea on exertion, and lower extremity edema. The patient reported a related medical history of hypertension, hyperlipidemia, and type II diabetes mellitus. He denied a history of swallowing abnormalities, stridor, and chronic respiratory problems. The physical examination was notable for coarse bibasilar breath sounds, and a grade II/VI crescendo-decrescendo systolic murmur heard best in the right second intercostal space that radiated to both carotid arteries (right4left). A transthoracic echocardiogram revealed that the aortic valve was a severely calcified trileaflet structure. Peak and mean gradients of 50 and 91 mmHg, respectively, were present across the valve. The aortic valve area calculated using the continuity equation was 0.71 cm2, consistent with severe stenosis. Mild-to-moderate aortic valve insufficiency, mild mitral valve regurgitation, and severe left ventricular hypertrophy also were observed. A cardiac catheterization verified these echocardiographic findings and revealed the presence of moderate pulmonary hypertension (pulmonary arterial systolic and diastolic pressures of 47 and 22 mmHg, respectively), but hemodynamically significant coronary artery stenoses were absent. The patient was transported to the operating room for aortic valve replacement. After anesthetic induction and endotracheal intubation, transesophageal echocardiography (TEE) was performed, which confirmed the diagnosis of severe aortic stenosis (Fig 1, Video 1). Withdrawal of the TEE probe to the upper
Fig 1. Midesophageal aortic valve short-axis TEE image showing severe calcification and stenosis of the aortic valve.
Fig 2. Upper esophageal TEE image showing distal main pulmonary artery and its bifurcation; the ascending aorta is absent despite manipulation of the probe.
esophageal imaging plane1 revealed bifurcation of a centrally located main pulmonary artery (Fig 2, Video 2), but the ascending aorta was not seen in this position despite flexionretroflexion and left or right rotation of the probe. Advancement of the TEE probe to a high midesophageal position showed a five-chamber image, and rotation of the probe approximately 451 to the right demonstrated a circular echolucent structure (Figs 3 and 4, Videos 3 and 4). What is the diagnosis?
From the *Anesthesia (PSP, RAB) Service, the Clement J. Zablocki Veterans Affairs Medical Center, Milwaukee, WI; and yCardiothoracic Surgery (GHA) Service, the Clement J. Zablocki Veterans Affairs Medical Center, Milwaukee, WI. Address reprint requests to Paul S. Pagel, MD, PhD, Clement J. Zablocki Veterans Affairs Medical Center, Anesthesia Service, 5000W. National Avenue, Milwaukee, WI 53295. E-mail: [email protected] & 2013 Elsevier Ltd. All rights reserved. 1053-0770/2602-0033$36.00/0 http://dx.doi.org/10.1053/j.jvca.2012.10.019 Key words: congenital heart disease, right aortic arch, thoracic imaging, cardiac embryology, fourth pharyngeal arch
Journal of Cardiothoracic and Vascular Anesthesia, Vol ], No ] (Month), ]]]]: pp ]]]–]]]
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PAGEL ET AL
Fig 3. High midesophageal TEE image showing five-chamber view and aortic valve calcification.
DIAGNOSIS: RIGHT AORTIC ARCH AND RIGHT DESCENDING THORACIC AORTA
The descending thoracic aorta was observed in the right hemithorax in a high midesophageal imaging plane (Fig 4, Videos 3 and 4). Gradual withdrawal of the probe from the esophagus demonstrated a short aortic arch that extended toward the patient’s left (Video 4). Computed tomography imaging without angiographic contrast showed that the ascending thoracic aorta was displaced to the right and the main pulmonary artery was shifted toward the aorta’s normal position (Fig 5). This change in orientation of the proximal great vessels accounted for the clear view of the main pulmonary artery and its bifurcation concomitant with the absence of the ascending thoracic aorta in the standard upper esophageal TEE imaging plane (Fig 2, Video 2). The aortic arch itself was attenuated in length and did not extend across the midline into the left hemithorax (Fig 6). The descending thoracic aorta was tortuous, but crossed the midline to enter the aortic hiatus of the diaphragm in the normal position (Fig 7). An aberrant origin of the left subclavian was noted on the posterior-lateral surface of the proximal descending thoracic aorta immediately below the arch (Fig 7). Direct inspection of the great vessels through a conventional median sternotomy incision during surgery confirmed many of the TEE and computed tomography findings. The heavily calcified native aortic valve was excised and replaced with a 25-mm bioprosthesis. The patient separated from cardiopulmonary bypass without inotropic support and was transferred to the intensive care unit in stable condition with excellent hemodynamics. The remainder of his hospital course was unremarkable. Fioratti and Aglietti first reported gross anatomic evidence of a human right aortic arch in 1763.2 Autopsy surveys and radiographic studies indicated that a right aorta arch is a rare finding that occurs in approximately 0.1% of adults.3 A right aortic arch is formed as a result of continued patency of the embryonic right fourth pharyngeal arch concomitant with simultaneous regression of its left counterpart.4,5 Deletions of chromosomal region 22q11 appear to affect fourth pharyngeal arch development by modulating neural crest migration and,
Fig 4. Short-axis TEE image of the right proximal descending thoracic aorta and origin of the left subclavian artery.
thus, have been proposed as a possible genetic etiology for right aortic arch.6-9 Five types of right aortic arch have been identified based on the anterior-posterior orientation of the arch relative to the esophagus, the site of origin of the left subclavian artery, and the location of the ductus arteriosus or the ligamentum arteriosum.10,11 The most common type of right aortic arch present in infancy and early childhood is characterized by mirror-image branching, in which a left innominate artery (giving rise to the left carotid and left subclavian arteries) is followed in sequence by the right carotid and right subclavian arteries.12,13 This mirror-image aortic arch lies anterior to the trachea and esophagus and is almost invariably associated with cyanotic congenital heart disease, among which tetralogy of Fallot (known as Corvisart disease) and truncus arteriosus are the most prevalent.11,12,14 Perhaps not surprisingly, the most common form of right aortic arch in adults is less frequently associated with other congenital heart defects.11,13 In sequence from proximal to distal, a right aortic arch with aberrant left subclavian artery presents with the left carotid, right carotid, and right subclavian arteries as the first 3 major branches. As observed in this patient (Video 4), the right aortic arch is located anterior to the trachea
Fig 5. Coronal CT image without angiographic contrast showing right displacement and orientation of the ascending thoracic aorta; the main pulmonary artery was shifted toward the aorta’s normal position. (CT, computed tomography.)
3
THE ASCENDING THORACIC AORTA STAGES A VANISHING ACT?
Fig 7. Coronal CT image without angiographic contrast showing tortuous course of the descending thoracic aorta and the origin of the left subclavian artery. (CT, computed tomography.)
Fig 6. Axial CT image without angiographic contrast showing short segment of right aortic arch; multiple areas of aortic calcification are also apparent. (CT, computed tomography.)
and esophagus, is typically quite short,15 and sharply terminates into a right descending thoracic aorta.16 The left subclavian artery is the most distal major vascular branch and arises from the proximal aspect of a right descending thoracic aorta.10 This configuration also was observed in this patient. The aberrant left subclavian artery frequently originates from a diverticulum (a remnant of the left fourth pharyngeal arch known as the diverticulum of Kommerell) and reaches the left upper extremity by crossing behind the esophagus from right to left. Many adults with this form of right aortic arch, including
this patient, are asymptomatic; the diagnosis often is incidental during the evaluation for other medical problems. However, a large diverticulum or aneurysmal dilation of the proximal left subclavian artery may compress the esophagus or right mainstem bronchus and cause swallowing or upper airway complications.3,17-19 The presence of an anomalous left ligamentum arteriosum may further increase the incidence of such esophageal or airway complications because of the formation of a vascular ring (consisting of the anterior right aortic arch, left subclavian artery posterior the esophagus, and the left ligamentum arteriosum, which connects the left subclavian to the left pulmonary artery).11 Indeed, a left ligamentum arteriosum is more common than its right-sided alternative, but many patients nevertheless remain completely asymptomatic because of the relative laxity of the resulting vascular ring.11,14
REFERENCES 1. Shanewise JS, Cheung AT, Aronson S, et al: ASE/SCA guidelines for performing a comprehensive intraoperative multiplane transesophageal echocardiography examination: Recommendations of the American Society of Echocardiography Council for Intraoperative Echocardiography and the Society of Cardiovascular Anesthesiologists Task Force for certification in perioperative transesophageal echocardiography. J Am Soc Echocardiogr 12:884-900, 1999 2. Sprong DH, Cutler NL: A case of human right aorta. Anat Rec 45: 365-375, 1930 3. Hafstreiter AR, D’Cruz IA, Cantez T: Right-sided aorta. Part I: Occurrence of right aortic arch in various types of congenital heart disease. Br Heart J 28:722-725, 1966 4. Vidne BA, Garti I, Rosenberg V, et al: Aortic arch anomalies: Simplified classification. Chest 62:39-44, 1972 5. McElhinney DB, Tworetzky W, Hanley FL, et al: Congenital obstructive lesions of the right aortic arch. Ann Thorac Surg 67: 1194-1202, 1999 6. Goldmuntz E, Driscoll D, Budarf ML, et al: Microdeletions of chromosomal region 22q11 in patients with congenital conotruncal cardiac defects. J Med Genet 30:807-812, 1993 7. Kirby ML, Waldo KL: Neural crest and cardiovascular patterning. Circ Res 77:211-215, 1995
8. Momma K, Matsuoka R, Takao A: Aortic arch anomalies associated with chromosome 22q11 deletion (CATCH 22). Pediatr Cardiol 20:97-102, 1999 9. Rauch R, Rauch A, Koch A, et al: Laterality of the aortic arch and anomalies of the subclavian artery-reliable indicators for 22q11.2 deletion syndromes? Eur J Pediatr 163:642-645, 2004 10. Knight L, Edwards JE: Right aortic arch. Types and associated cardiac anomalies. Circulation 50:1047-1051, 1974 11. VanDyke CW, White RD: Congenital abnormalities of the thoracic aorta presenting in the adult. J Thorac Imag 9:230-245, 1994 12. D’Cruz IA, Cantex T, Namin EP, et al: Right-sided aorta. Part II: Right aortic arch, right descending aorta, and associated anomalies. Br Heart J 28:725-739, 1966 13. Stewart JR, Kincaid OW, Titus JL: Right aortic arch: Plain film diagnosis and significance. AJR Am J Roentgenol 97:377-389, 1966 14. Felson B, Palayew MJ: The two types of right aortic arch. Radiology 81:745-759, 1963 15. Bhatnagar KP, Wagner CE, Kuwubara N, et al: Right-sided aorta: A cadaver report and brief discussion of human aortic arch anomalies. Ann Anat 182:559-562, 2000 16. Shuford WH, Sybers RG, Edwards FK: The three types of right aortic arch. AJR Am J Roentgenol 109:67-74, 1970
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17. Bose S, Hurst TS, Cockcroft DW: Right-sided aortic arch presenting as refractory intraoperative and postoperative wheezing. Chest 99:1308-1310, 1991 18. Patiniotis RC, Mohajeri M, Hill DG: Right aortic arch with aberrant left subclavian artery: Aneurysmal dilatation causing
PAGEL ET AL
symptomatic compression of the right main bronchus in an adult. Aust N Z J Surg 65:690-692, 1995 19. Nanda NC, Samal AK, Bakir S, et al: Transesophageal echocardiographic diagnosis of right-sided aortic arch. Echocardiography 4: 409-417, 1998
The Ascending Thoracic Aorta Stages a Vanishing Act? Paul S. Pagel, MD, PhD,* Robert A. Biechler, MD,* and G. Hossein Almassi, MD†
A
N 85-YEAR-OLD, 101-kg, 168-cm tall man was admitted to the institution for evaluation of syncope, exertional chest pain radiating to his left shoulder, progressive dyspnea on exertion, and lower extremity edema. The patient reported a related medical history of hypertension, hyperlipidemia, and type II diabetes mellitus. He denied a history of swallowing abnormalities, stridor, and chronic respiratory problems. The physical examination was notable for coarse bibasilar breath sounds, and a grade II/VI crescendo-decrescendo systolic murmur heard best in the right second intercostal space that radiated to both carotid arteries (right4left). A transthoracic echocardiogram revealed that the aortic valve was a severely calcified trileaflet structure. Peak and mean gradients of 50 and 91 mmHg, respectively, were present across the valve. The aortic valve area calculated using the continuity equation was 0.71 cm2, consistent with severe stenosis. Mild-to-moderate aortic valve insufficiency, mild mitral valve regurgitation, and severe left ventricular hypertrophy also were observed. A cardiac catheterization verified these echocardiographic findings and revealed the presence of moderate pulmonary hypertension (pulmonary arterial systolic and diastolic pressures of 47 and 22 mmHg, respectively), but hemodynamically significant coronary artery stenoses were absent. The patient was transported to the operating room for aortic valve replacement. After anesthetic induction and endotracheal intubation, transesophageal echocardiography (TEE) was performed, which confirmed the diagnosis of severe aortic stenosis (Fig 1, Video 1). Withdrawal of the TEE probe to the upper
Fig 1. Midesophageal aortic valve short-axis TEE image showing severe calcification and stenosis of the aortic valve.
Fig 2. Upper esophageal TEE image showing distal main pulmonary artery and its bifurcation; the ascending aorta is absent despite manipulation of the probe.
esophageal imaging plane1 revealed bifurcation of a centrally located main pulmonary artery (Fig 2, Video 2), but the ascending aorta was not seen in this position despite flexionretroflexion and left or right rotation of the probe. Advancement of the TEE probe to a high midesophageal position showed a five-chamber image, and rotation of the probe approximately 451 to the right demonstrated a circular echolucent structure (Figs 3 and 4, Videos 3 and 4). What is the diagnosis?
From the *Anesthesia (PSP, RAB) Service, the Clement J. Zablocki Veterans Affairs Medical Center, Milwaukee, WI; and yCardiothoracic Surgery (GHA) Service, the Clement J. Zablocki Veterans Affairs Medical Center, Milwaukee, WI. Address reprint requests to Paul S. Pagel, MD, PhD, Clement J. Zablocki Veterans Affairs Medical Center, Anesthesia Service, 5000W. National Avenue, Milwaukee, WI 53295. E-mail: [email protected] & 2013 Elsevier Ltd. All rights reserved. 1053-0770/2602-0033$36.00/0 http://dx.doi.org/10.1053/j.jvca.2012.10.019 Key words: congenital heart disease, right aortic arch, thoracic imaging, cardiac embryology, fourth pharyngeal arch
Journal of Cardiothoracic and Vascular Anesthesia, Vol ], No ] (Month), ]]]]: pp ]]]–]]]
1
2
PAGEL ET AL
Fig 3. High midesophageal TEE image showing five-chamber view and aortic valve calcification.
DIAGNOSIS: RIGHT AORTIC ARCH AND RIGHT DESCENDING THORACIC AORTA
The descending thoracic aorta was observed in the right hemithorax in a high midesophageal imaging plane (Fig 4, Videos 3 and 4). Gradual withdrawal of the probe from the esophagus demonstrated a short aortic arch that extended toward the patient’s left (Video 4). Computed tomography imaging without angiographic contrast showed that the ascending thoracic aorta was displaced to the right and the main pulmonary artery was shifted toward the aorta’s normal position (Fig 5). This change in orientation of the proximal great vessels accounted for the clear view of the main pulmonary artery and its bifurcation concomitant with the absence of the ascending thoracic aorta in the standard upper esophageal TEE imaging plane (Fig 2, Video 2). The aortic arch itself was attenuated in length and did not extend across the midline into the left hemithorax (Fig 6). The descending thoracic aorta was tortuous, but crossed the midline to enter the aortic hiatus of the diaphragm in the normal position (Fig 7). An aberrant origin of the left subclavian was noted on the posterior-lateral surface of the proximal descending thoracic aorta immediately below the arch (Fig 7). Direct inspection of the great vessels through a conventional median sternotomy incision during surgery confirmed many of the TEE and computed tomography findings. The heavily calcified native aortic valve was excised and replaced with a 25-mm bioprosthesis. The patient separated from cardiopulmonary bypass without inotropic support and was transferred to the intensive care unit in stable condition with excellent hemodynamics. The remainder of his hospital course was unremarkable. Fioratti and Aglietti first reported gross anatomic evidence of a human right aortic arch in 1763.2 Autopsy surveys and radiographic studies indicated that a right aorta arch is a rare finding that occurs in approximately 0.1% of adults.3 A right aortic arch is formed as a result of continued patency of the embryonic right fourth pharyngeal arch concomitant with simultaneous regression of its left counterpart.4,5 Deletions of chromosomal region 22q11 appear to affect fourth pharyngeal arch development by modulating neural crest migration and,
Fig 4. Short-axis TEE image of the right proximal descending thoracic aorta and origin of the left subclavian artery.
thus, have been proposed as a possible genetic etiology for right aortic arch.6-9 Five types of right aortic arch have been identified based on the anterior-posterior orientation of the arch relative to the esophagus, the site of origin of the left subclavian artery, and the location of the ductus arteriosus or the ligamentum arteriosum.10,11 The most common type of right aortic arch present in infancy and early childhood is characterized by mirror-image branching, in which a left innominate artery (giving rise to the left carotid and left subclavian arteries) is followed in sequence by the right carotid and right subclavian arteries.12,13 This mirror-image aortic arch lies anterior to the trachea and esophagus and is almost invariably associated with cyanotic congenital heart disease, among which tetralogy of Fallot (known as Corvisart disease) and truncus arteriosus are the most prevalent.11,12,14 Perhaps not surprisingly, the most common form of right aortic arch in adults is less frequently associated with other congenital heart defects.11,13 In sequence from proximal to distal, a right aortic arch with aberrant left subclavian artery presents with the left carotid, right carotid, and right subclavian arteries as the first 3 major branches. As observed in this patient (Video 4), the right aortic arch is located anterior to the trachea
Fig 5. Coronal CT image without angiographic contrast showing right displacement and orientation of the ascending thoracic aorta; the main pulmonary artery was shifted toward the aorta’s normal position. (CT, computed tomography.)
3
THE ASCENDING THORACIC AORTA STAGES A VANISHING ACT?
Fig 7. Coronal CT image without angiographic contrast showing tortuous course of the descending thoracic aorta and the origin of the left subclavian artery. (CT, computed tomography.)
Fig 6. Axial CT image without angiographic contrast showing short segment of right aortic arch; multiple areas of aortic calcification are also apparent. (CT, computed tomography.)
and esophagus, is typically quite short,15 and sharply terminates into a right descending thoracic aorta.16 The left subclavian artery is the most distal major vascular branch and arises from the proximal aspect of a right descending thoracic aorta.10 This configuration also was observed in this patient. The aberrant left subclavian artery frequently originates from a diverticulum (a remnant of the left fourth pharyngeal arch known as the diverticulum of Kommerell) and reaches the left upper extremity by crossing behind the esophagus from right to left. Many adults with this form of right aortic arch, including
this patient, are asymptomatic; the diagnosis often is incidental during the evaluation for other medical problems. However, a large diverticulum or aneurysmal dilation of the proximal left subclavian artery may compress the esophagus or right mainstem bronchus and cause swallowing or upper airway complications.3,17-19 The presence of an anomalous left ligamentum arteriosum may further increase the incidence of such esophageal or airway complications because of the formation of a vascular ring (consisting of the anterior right aortic arch, left subclavian artery posterior the esophagus, and the left ligamentum arteriosum, which connects the left subclavian to the left pulmonary artery).11 Indeed, a left ligamentum arteriosum is more common than its right-sided alternative, but many patients nevertheless remain completely asymptomatic because of the relative laxity of the resulting vascular ring.11,14
REFERENCES 1. Shanewise JS, Cheung AT, Aronson S, et al: ASE/SCA guidelines for performing a comprehensive intraoperative multiplane transesophageal echocardiography examination: Recommendations of the American Society of Echocardiography Council for Intraoperative Echocardiography and the Society of Cardiovascular Anesthesiologists Task Force for certification in perioperative transesophageal echocardiography. J Am Soc Echocardiogr 12:884-900, 1999 2. Sprong DH, Cutler NL: A case of human right aorta. Anat Rec 45: 365-375, 1930 3. Hafstreiter AR, D’Cruz IA, Cantez T: Right-sided aorta. Part I: Occurrence of right aortic arch in various types of congenital heart disease. Br Heart J 28:722-725, 1966 4. Vidne BA, Garti I, Rosenberg V, et al: Aortic arch anomalies: Simplified classification. Chest 62:39-44, 1972 5. McElhinney DB, Tworetzky W, Hanley FL, et al: Congenital obstructive lesions of the right aortic arch. Ann Thorac Surg 67: 1194-1202, 1999 6. Goldmuntz E, Driscoll D, Budarf ML, et al: Microdeletions of chromosomal region 22q11 in patients with congenital conotruncal cardiac defects. J Med Genet 30:807-812, 1993 7. Kirby ML, Waldo KL: Neural crest and cardiovascular patterning. Circ Res 77:211-215, 1995
8. Momma K, Matsuoka R, Takao A: Aortic arch anomalies associated with chromosome 22q11 deletion (CATCH 22). Pediatr Cardiol 20:97-102, 1999 9. Rauch R, Rauch A, Koch A, et al: Laterality of the aortic arch and anomalies of the subclavian artery-reliable indicators for 22q11.2 deletion syndromes? Eur J Pediatr 163:642-645, 2004 10. Knight L, Edwards JE: Right aortic arch. Types and associated cardiac anomalies. Circulation 50:1047-1051, 1974 11. VanDyke CW, White RD: Congenital abnormalities of the thoracic aorta presenting in the adult. J Thorac Imag 9:230-245, 1994 12. D’Cruz IA, Cantex T, Namin EP, et al: Right-sided aorta. Part II: Right aortic arch, right descending aorta, and associated anomalies. Br Heart J 28:725-739, 1966 13. Stewart JR, Kincaid OW, Titus JL: Right aortic arch: Plain film diagnosis and significance. AJR Am J Roentgenol 97:377-389, 1966 14. Felson B, Palayew MJ: The two types of right aortic arch. Radiology 81:745-759, 1963 15. Bhatnagar KP, Wagner CE, Kuwubara N, et al: Right-sided aorta: A cadaver report and brief discussion of human aortic arch anomalies. Ann Anat 182:559-562, 2000 16. Shuford WH, Sybers RG, Edwards FK: The three types of right aortic arch. AJR Am J Roentgenol 109:67-74, 1970
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17. Bose S, Hurst TS, Cockcroft DW: Right-sided aortic arch presenting as refractory intraoperative and postoperative wheezing. Chest 99:1308-1310, 1991 18. Patiniotis RC, Mohajeri M, Hill DG: Right aortic arch with aberrant left subclavian artery: Aneurysmal dilatation causing
PAGEL ET AL
symptomatic compression of the right main bronchus in an adult. Aust N Z J Surg 65:690-692, 1995 19. Nanda NC, Samal AK, Bakir S, et al: Transesophageal echocardiographic diagnosis of right-sided aortic arch. Echocardiography 4: 409-417, 1998