CASE REPORTS
Dissecting Aortic Aneurysm Involving a Right-Sided Aortic Arch
PETER
ROAN,
STEPHEN
L. MAXIMILIAN AARON
MD
PARISH,
MD
BUJA,
ESTRERA,
LAWRENCE
MD,
MD,
MILLS,
JAMES
ATKINS,
JAMES
WILLERSON,
MD,
MD,
FACC
FACC FACC
FACC MD,
FACC
In this case, the first reported instance of aortic dissection involving a right-sided arch, an anomalous fourth arch vessel, the left subclavian artery, arose from a congenital aortk diverticulum. This report emphasizes the need for precise anatomic definition with aortography to permit appropriate therapy when congenital anomalies of the aortic arch are complicated by dissecting hematoma.
Dallas, Texas
Although right-sided aortic arch is not rare, there is little information related to acquired disease of the great vessels associated with this anomaly. The present case constitutes, to our knowledge, the first reported instance of aortic dissection involving a right-sided arch. Case Report Patient Information
From the Departments of Internal Medicine (Cardiac Unit), Pathology and Surgery (Thoracic Surgery Division), at The University of Texas Health Science Center and Parkland Memorial Hospital, Dallas, Texas. This work was supported by NIH lschemic Heart Disease Specialized Center of Research (SCDR) Grant HL 17669, Bethesda, Maryland. Manuscript received December 12, 1978; revised manuscript received February 13. 1979, accepted February 16, 1979. Address for reprints: Peter Roan, MD, Department of Internal Medicine, H&l 16, The University of Texas Health Science Center at Dallas, 5323 Harry Hines Boulevard, Dallas, Texas 75235.
The patient, a 48 year old black woman, was admitted to Parkland Memorial Hospital on July 19,1977 with a complaint of chest pain. Systemic arterial hypertension had. been detected in 1963, and 3 years later the patient had rightsided headaches with a paralysis of the right sixth cranial nerve. Cerebral arteriography revealed an aneurysm of the right internal carotid artery within the cavernous sinus, but an arch aortogram was not performed. Subsequent ligation of the right common carotid artery resulted in residual mild left hemiparesis. In May 1974, the patient presented to the emergency room with severe interscapular back pain. Roentgenograms of the chest revealed a widened mediastinum. Although it was recognized that the patient had a right-sided aortic arch, an aortogram was performed in a “standard” left anterior oblique projection; no eviden.ce of a dissection was noted, and the pain was ascribed to “musculoskeletal” causes. During follow-up in the outpatient clinic, her blood pressures ranged from 160/120 to 140/80 mm Hg. In July 1976, she experienced dysphagia for solid foods; a barium swallow demonstrated posterior compression of the esophagus by what was thought to be a large aortic diverticulum. A year later she was awakened with a “gripping” pain between the scapulae. The next day the pain was episodic and “crushing” in quality but the patient continued to work. She experienced no dyspnea, hemoptysis, edema or orthopnea. She did not seek medical attention until the following day when she was seen for a routine pelvic examination. !She was then hospitalized. On physical examination, the patient was thin and well developed (weight 51 kg) without any of the stigmata of Marfan’s syndrome, and in no distress. Blood pressures (mm Hg) were: right arm 160/94, left arm 166/74, right leg 150/96 and left leg 150/110. Pulse rate was 72/min and respirations 16/min. There was a Marcus-Gunn pupil noted on the right. Funduscopic examination revealed arteriovenous crossing defects without hemorrhage, exudates or papilledema. The right carotid pulse was absent. The chest was clear to auscultation and percussion. Cardiac examination revealed the point of maximal impulse to be in the mid clavicular line in the sixth intercostal space. An ectopic impulse was palpated in the third right intercostal space. No pulsation of the sternoclavicular
August 1979
The American Journal of CARDIOLOGY
Volume 44
381
DISSECTION WITH RIGHT-SIDED AORTIC ARCH-ROAN
ET AL.
FIGURE 1. Chest roentgenwarns, posteroanterior (left) and lateral (right) views, taken at the time of the patient’s last admission. A tortuous. aneurysmally dilated right aortic arch is present. A surgical clip, present in the apical region of the right lung field, was @aced during a previous operation and occludes the right common carotid artery.
joints was noted. The first heart sound was normal and the second heart sound split physiologically with inspiration. There was a fourth heart sound and an aortic ejection click. A grade 216 systolic ejection murmur was noted in the right second intercostal space and a l/6 diastolic decrescendo murmur heard best at the apex. Peripheral pulses were intact and equal. Roentgenogram of the chest (Fig. 1) demonstrated a tortuous right-sided aortic arch and a widened mediastinum with no change from the 1974 roentgenogram. Electrocardiogram demonstrated nonspecific S-T and T wave changes. Laboratory studies were normal except for a prolonged prothrombin time of 13.5 seconds with a control time of 11.0 seconds. Results of the Venereal Disease Research Laboratory test were negative. Treatment Pharmacologic therapy, intravenously and orally, was initiated with reserpine and propranolol according to the recommendation of Wheat.l Systemic arterial pressure was maintained at 100/50 mm Hg; perfusion of the vital organs was well preserved. The day after admission an arch aortogram was performed (Fig. 2). This demonstrated that four vessels originated from the arch in the following order: a left common carotid, a right common carotid, a right subclavian and an aberrant left subclavian artery; the latter arose from an aortic diverticulum and coursed posterior to the esophagus. An aortic dissection appeared to idvolve the aortic diverticulum and right subclavian artery. The latter vessel did not clearly opacify with an aortic root injection but was defined with a selective subclavian injection during cineangiography. The dissection compressed the true lumen of the descending aorta, and opacification of the false lumen was noted. Opacification of the false channel is known to be associated with a relatively poor survival with medical therapy.2 Surgical therapy was therefore recommended and an operation was performed the same day. A right posterolateral thoracotomy adequately exposed the arch and descending aorta. Exploration of the aorta revealed a dissecting aneurysm that extended from the level of the right subclavian artery
382
August 1879
The American Journal 01 CARDIOLOGY
distally into the descending thoracic aorta. The lumen of the descetiding portion was compressed to a 1 cm diameter by the dissection. The false lumen in this region was filled with old gelatinous material. With the patient on partial cardiopulmonary bypass from the right femoral vein to the right femoral arteri, a 26 mm Cooley woven Dacron@ graft was inserted between the origin of the subclavian artery and the descending aorta. The diverticulum, which formed the origin of the left subclavian artery, could not be attached to the graft and was therefqre ligated. The patient remained comatose and areflexic after operation and died 3 days later. Autopsy Findings Gross examination revealed a right-sided aortic arch with the descending aorta lying to the right of the spine (Fig. 3). Arising from the aortic arch (proximal to distal) were the left common carotid artery, the right common carotid artery, the right subclavian artery and a retroesophageal left subclavian artery arising from an aortic diverticulum. A left ligamenturn arteriosum connected the aortic diverticulum an4 pulmonary trunk, thereby completing a vascular ring. The right common carotid artery had a metal clip attached at the site of the old surgical occlusion. Old dissection extended from the region of the aortic diverticulum distally to the renal arteries. The aortic diverticulum clearly represented a congenital and not an acquired anomaly that was only partially involved by the dissection. The old dissection connected proximally with an area of recent dissection extending into the right subclavian artery. The false lumen in the area of recent dissection was filled with hematoma. The old dissection had two false lumens lined by thickened neointimal tissue; one of these lumens was filled with old thrombus. The surgical graft extended from the region of the aortic diverticulum and was anastomosed to the descending aorta. On microscopic examination Erdheim’s cystic medionecrosis of a severe degree was found in the ascending aorta and in the great vessels. The aortic valve had three cusps but the posterior and left cusps were fused, probably as a result of healed degenerative endocardiosis (nonbacterial thrombotic endocarditis), producing a bicuspid valve. The heart weighed
Volume 44
DISSECTKIN
WITH
RIGHT-S:DEO
AOr-‘C
,~,“‘~u__PcA~
‘-
A’_,
FIGURE 2. Left anterior oblique (left) and right anterior oblique (right) projections of an arch aortogram taken the day after admission. Branches of the right-sided aortic arch from proximal to distal include the “stump” of the previously occluded right common carotid artery (RCCA), the left common carotid artery (LCCA), the right subciavian artery (not visualized on arch aortography, but seen with a selective injection of the right subciavian during cineangiography) and the left subciavian artery (LSA). The latter arises from an aortic diverticuium (DIV). Note the opacification of an aortic aneurysm (A) and of the false channel (open arrow). The true lumen of the distal aorta is compressed by the dissection.
340 g and manifested both left ventricular hypertrophy and dilatation. Massive bilateral cerebral infarcts were present with herniation of the cerebellar tonsils.
Discussion Types of right aortic arch: This case constitutes the first reported instance of dissection involving a rightsided arch. The latter, an uncommon anomaly first described in 1763,3 is found in approximately 0.1 percent of the general population. Right-sided arches can be classified into two major anatomic types depending on the branching characteristics of the great vessels.4 In the first type three great vessels arise from the aortic arch in a mirror image of the normal pattern of branching; thus, the left innominate artery arises most proximally, followed by the right common carotid and then the right subclavian arteries. The aorta descends most often to the right of the spine and the ductus arteriosus most commonly connects the left subclavian artery to the left pulmonary artery, although the ductus may be right-sided or bilateral. Cyanotic congenital heart disease is found in approximately 75 percent of the patients with the mirror-image form of right-sided arch, most commonly tetralogy of Fallot, truncus arteriosus and tricuspid atresia.“,6 In patients with a clinically suspected diagnosis of pulmonary stenosis, the presence of a right-sided arch strongly suggests a coexistent ventricular septal defect.7 The most common type of right aortic arch is illustrated by our case. In this type four arch vessels branch, proximally to distally, in the following order: a left common carotid, a right common carotid, a right subclavian and an aberrant left subclavian artery. The latter vessel arises from a conical aortic diverticulum and courses posterior to the esophagus to reach the left arm (Fig. 3). In contrast to the mirror-image form, in this type of right-sided arch, congenital heart disease occurs in only 5 to 10 percent of patients. However, because the ductus arteriosus usually connects either
the aortic diverticulum or the left subclavian artery to the left pulmonary artery, a vascular ring is formed. Trachea-esophageal compression may thus occur, manifested by noisy respiration, recurrent pulmonary infections and dysphagia early in 1ife.s However, three fourths of patients are asymptomatic and do not require surgery. Embryologically the proximal portion of the left aortic arch forms the left common carotid artery and distally persists as an aortic diverticulum, giving rise to the left subclavian artery.4,10 Associated aortic disease and differential diagnosis: Acquired disease of the aorta does not. appear to
R. COMMON CAROTID WITH OLD SURGICAL R. VERTEBRAL R. SUBCLAVIAN
A. OCCLUSION ‘\ A.
ESOPHAGUS ”
TRfICHEA .ID A.
A_ ,L
RECENT
DISSECTION
,_L
AORTIC DlVERTlCULUM
VERTEBRAL
A
SUBCLAVIAN
A.
ARTERIOSUM PULMONARY
OLD
DISSECTION THROMBUS FALSE LUMEN
u
L
RENAL
A.
FIGURE 3. Diagram of the anatomic features found at autopsy. The diverticuium and left subclavian artery coursed posterior to the esophagus. The iigamentum arteriosum connected the diverticulum to the pulmonary trunk and thereby formed a vascular ring. A. = artery; L. = left; Ft. = right.
August 1979
The American Journal of CARDIOLOGY
Volume 44
383
DISSECTION
WITH RIGHT-SIDED AORTIC ARCH-ROAN
ET AL.
occur with increased frequency in patients with a right-sided arch. However, in patients with a left-sided arch and an aberrant right subclavian artery, dissections are known to occur.11J2 In one such case the aortic diverticulum was mistaken for an aortic aneurysm and resected, and the patient died 3 months later from a ruptured suture line. 13 Unnecessary exploratory thoracotomy has been performed when right-sided arches have been mistaken for superior mediastinal masses.7 Right-sided arch and aortic diverticuli thus represent congenital anomalies that can be confused with acquired disease processes. Diagnosis and treatment of aortic dissection: Confusion regarding the anatomy of these congenital anomalies may result in the performance of inadequate diagnostic studies. In our case the initial performance of aortography in a left anterior oblique position re-
sulted in poor visualization of the arch. On subsequent review of these films a diagnosis of aortic dissection could not be excluded with confidence. Later at operation the aortic diverticulum was thought to be involved by the dissection, which necessitated the surgical ligation of the left subclavian artery. This was particularly unfortunate in our case because the right common carotid artery had been ligated previously, and the right subclavian and vertebral arteries, although patent, were compromised by recent dissection. The entire cerebral vascular circulation thus became dependent on the left common carotid artery. Thus, precise definition of the pathoanatomy is essential before a therapeutic program for aortic dissection is begun. If uncertainty exists, repeat aortography and the continuation of aggressive medical therapy may be the best approach.
References 1. Wheat MW Jr: Treatment of dissecting aneurysms of the aorta: current status. Prog Cardiovasc Dis 16:87-101, 1973 2. MacFarland J, WilIerson JT, Dinsmore RE, Buckley MJ, Austen MG, Saunders CA, De Sanctls RW: The medical treatment of dissecting aortic aneurysms. N Engi J Med 286:115-l 19, 1972 3. Sprang DH, Cutler NC: A case of human right aorta. Anat Ret 45: 365-375, 1930 4. SJurford WH, Sybers RG: RigM aortic arch. in, The Aortic Arch and its Malformations. Springfield, IL. Charles C Thomas, 1974, p 52-68 5. Stewart JR, Klncald OW, THUS JL: Right aortic arch: plain film diagnosis and significance. Am J Roentgenoi 97:377-389, 1966 6. Stewart JR, Klncald OW, Edwards JE: An Atlas of Vascular Rings and Related Malformations of the Aortic Arch System. Springfield, IL, Charles C Thomas, 1964, p 8-13, 124-219. 7. Hastrelter AR, d’Cruz IA, Cantez T: Right sided aorta. Br Heart J
384
August 1979
The American Journal of CARDIOLOGY
28:722-739, 1966 8. Klrklln JW, Paciflco AD: Surgical treatment of congenital heart disease. in, The Heart (Hurst JW, ed). New York, McGraw-Hill, 1974, p 779-781 9. Fontana RS, Edwards JE: Congenital Cardiac Disease: A Review of 357 Cases Studied Pathologically. Philadelphia, WB Saunders, 1982 10. Patten BY: Tha development of the heart. In, Pathology of the Heart and Blood Vessels, third edition (Gould SE. ed). Sorinafieid. IL. Charles C Thomas, 1968, p 20 11. Syme J: Aortic dissection involving an aberrant right subclavian artery studied by aortography. Aust Radioi 17: 174- 179, 1973 12. Rbhards WCD, EllIoti CE: Aneurysm of an anomalous right subciavian artery. Br Heart J 19:141-143,1957 13. Shannon JM: Aberrant right subciavian artery with Kommereii’s diverticuium. J Thorac Surg 41:408-4 11, 1961
Volume 44
Dissecting Aortic Aneurysm Involving a Right-Sided Aortic Arch
PETER
ROAN,
STEPHEN
L. MAXIMILIAN AARON
MD
PARISH,
MD
BUJA,
ESTRERA,
LAWRENCE
MD,
MD,
MILLS,
JAMES
ATKINS,
JAMES
WILLERSON,
MD,
MD,
FACC
FACC FACC
FACC MD,
FACC
In this case, the first reported instance of aortic dissection involving a right-sided arch, an anomalous fourth arch vessel, the left subclavian artery, arose from a congenital aortk diverticulum. This report emphasizes the need for precise anatomic definition with aortography to permit appropriate therapy when congenital anomalies of the aortic arch are complicated by dissecting hematoma.
Dallas, Texas
Although right-sided aortic arch is not rare, there is little information related to acquired disease of the great vessels associated with this anomaly. The present case constitutes, to our knowledge, the first reported instance of aortic dissection involving a right-sided arch. Case Report Patient Information
From the Departments of Internal Medicine (Cardiac Unit), Pathology and Surgery (Thoracic Surgery Division), at The University of Texas Health Science Center and Parkland Memorial Hospital, Dallas, Texas. This work was supported by NIH lschemic Heart Disease Specialized Center of Research (SCDR) Grant HL 17669, Bethesda, Maryland. Manuscript received December 12, 1978; revised manuscript received February 13. 1979, accepted February 16, 1979. Address for reprints: Peter Roan, MD, Department of Internal Medicine, H&l 16, The University of Texas Health Science Center at Dallas, 5323 Harry Hines Boulevard, Dallas, Texas 75235.
The patient, a 48 year old black woman, was admitted to Parkland Memorial Hospital on July 19,1977 with a complaint of chest pain. Systemic arterial hypertension had. been detected in 1963, and 3 years later the patient had rightsided headaches with a paralysis of the right sixth cranial nerve. Cerebral arteriography revealed an aneurysm of the right internal carotid artery within the cavernous sinus, but an arch aortogram was not performed. Subsequent ligation of the right common carotid artery resulted in residual mild left hemiparesis. In May 1974, the patient presented to the emergency room with severe interscapular back pain. Roentgenograms of the chest revealed a widened mediastinum. Although it was recognized that the patient had a right-sided aortic arch, an aortogram was performed in a “standard” left anterior oblique projection; no eviden.ce of a dissection was noted, and the pain was ascribed to “musculoskeletal” causes. During follow-up in the outpatient clinic, her blood pressures ranged from 160/120 to 140/80 mm Hg. In July 1976, she experienced dysphagia for solid foods; a barium swallow demonstrated posterior compression of the esophagus by what was thought to be a large aortic diverticulum. A year later she was awakened with a “gripping” pain between the scapulae. The next day the pain was episodic and “crushing” in quality but the patient continued to work. She experienced no dyspnea, hemoptysis, edema or orthopnea. She did not seek medical attention until the following day when she was seen for a routine pelvic examination. !She was then hospitalized. On physical examination, the patient was thin and well developed (weight 51 kg) without any of the stigmata of Marfan’s syndrome, and in no distress. Blood pressures (mm Hg) were: right arm 160/94, left arm 166/74, right leg 150/96 and left leg 150/110. Pulse rate was 72/min and respirations 16/min. There was a Marcus-Gunn pupil noted on the right. Funduscopic examination revealed arteriovenous crossing defects without hemorrhage, exudates or papilledema. The right carotid pulse was absent. The chest was clear to auscultation and percussion. Cardiac examination revealed the point of maximal impulse to be in the mid clavicular line in the sixth intercostal space. An ectopic impulse was palpated in the third right intercostal space. No pulsation of the sternoclavicular
August 1979
The American Journal of CARDIOLOGY
Volume 44
381
DISSECTION WITH RIGHT-SIDED AORTIC ARCH-ROAN
ET AL.
FIGURE 1. Chest roentgenwarns, posteroanterior (left) and lateral (right) views, taken at the time of the patient’s last admission. A tortuous. aneurysmally dilated right aortic arch is present. A surgical clip, present in the apical region of the right lung field, was @aced during a previous operation and occludes the right common carotid artery.
joints was noted. The first heart sound was normal and the second heart sound split physiologically with inspiration. There was a fourth heart sound and an aortic ejection click. A grade 216 systolic ejection murmur was noted in the right second intercostal space and a l/6 diastolic decrescendo murmur heard best at the apex. Peripheral pulses were intact and equal. Roentgenogram of the chest (Fig. 1) demonstrated a tortuous right-sided aortic arch and a widened mediastinum with no change from the 1974 roentgenogram. Electrocardiogram demonstrated nonspecific S-T and T wave changes. Laboratory studies were normal except for a prolonged prothrombin time of 13.5 seconds with a control time of 11.0 seconds. Results of the Venereal Disease Research Laboratory test were negative. Treatment Pharmacologic therapy, intravenously and orally, was initiated with reserpine and propranolol according to the recommendation of Wheat.l Systemic arterial pressure was maintained at 100/50 mm Hg; perfusion of the vital organs was well preserved. The day after admission an arch aortogram was performed (Fig. 2). This demonstrated that four vessels originated from the arch in the following order: a left common carotid, a right common carotid, a right subclavian and an aberrant left subclavian artery; the latter arose from an aortic diverticulum and coursed posterior to the esophagus. An aortic dissection appeared to idvolve the aortic diverticulum and right subclavian artery. The latter vessel did not clearly opacify with an aortic root injection but was defined with a selective subclavian injection during cineangiography. The dissection compressed the true lumen of the descending aorta, and opacification of the false lumen was noted. Opacification of the false channel is known to be associated with a relatively poor survival with medical therapy.2 Surgical therapy was therefore recommended and an operation was performed the same day. A right posterolateral thoracotomy adequately exposed the arch and descending aorta. Exploration of the aorta revealed a dissecting aneurysm that extended from the level of the right subclavian artery
382
August 1879
The American Journal 01 CARDIOLOGY
distally into the descending thoracic aorta. The lumen of the descetiding portion was compressed to a 1 cm diameter by the dissection. The false lumen in this region was filled with old gelatinous material. With the patient on partial cardiopulmonary bypass from the right femoral vein to the right femoral arteri, a 26 mm Cooley woven Dacron@ graft was inserted between the origin of the subclavian artery and the descending aorta. The diverticulum, which formed the origin of the left subclavian artery, could not be attached to the graft and was therefqre ligated. The patient remained comatose and areflexic after operation and died 3 days later. Autopsy Findings Gross examination revealed a right-sided aortic arch with the descending aorta lying to the right of the spine (Fig. 3). Arising from the aortic arch (proximal to distal) were the left common carotid artery, the right common carotid artery, the right subclavian artery and a retroesophageal left subclavian artery arising from an aortic diverticulum. A left ligamenturn arteriosum connected the aortic diverticulum an4 pulmonary trunk, thereby completing a vascular ring. The right common carotid artery had a metal clip attached at the site of the old surgical occlusion. Old dissection extended from the region of the aortic diverticulum distally to the renal arteries. The aortic diverticulum clearly represented a congenital and not an acquired anomaly that was only partially involved by the dissection. The old dissection connected proximally with an area of recent dissection extending into the right subclavian artery. The false lumen in the area of recent dissection was filled with hematoma. The old dissection had two false lumens lined by thickened neointimal tissue; one of these lumens was filled with old thrombus. The surgical graft extended from the region of the aortic diverticulum and was anastomosed to the descending aorta. On microscopic examination Erdheim’s cystic medionecrosis of a severe degree was found in the ascending aorta and in the great vessels. The aortic valve had three cusps but the posterior and left cusps were fused, probably as a result of healed degenerative endocardiosis (nonbacterial thrombotic endocarditis), producing a bicuspid valve. The heart weighed
Volume 44
DISSECTKIN
WITH
RIGHT-S:DEO
AOr-‘C
,~,“‘~u__PcA~
‘-
A’_,
FIGURE 2. Left anterior oblique (left) and right anterior oblique (right) projections of an arch aortogram taken the day after admission. Branches of the right-sided aortic arch from proximal to distal include the “stump” of the previously occluded right common carotid artery (RCCA), the left common carotid artery (LCCA), the right subciavian artery (not visualized on arch aortography, but seen with a selective injection of the right subciavian during cineangiography) and the left subciavian artery (LSA). The latter arises from an aortic diverticuium (DIV). Note the opacification of an aortic aneurysm (A) and of the false channel (open arrow). The true lumen of the distal aorta is compressed by the dissection.
340 g and manifested both left ventricular hypertrophy and dilatation. Massive bilateral cerebral infarcts were present with herniation of the cerebellar tonsils.
Discussion Types of right aortic arch: This case constitutes the first reported instance of dissection involving a rightsided arch. The latter, an uncommon anomaly first described in 1763,3 is found in approximately 0.1 percent of the general population. Right-sided arches can be classified into two major anatomic types depending on the branching characteristics of the great vessels.4 In the first type three great vessels arise from the aortic arch in a mirror image of the normal pattern of branching; thus, the left innominate artery arises most proximally, followed by the right common carotid and then the right subclavian arteries. The aorta descends most often to the right of the spine and the ductus arteriosus most commonly connects the left subclavian artery to the left pulmonary artery, although the ductus may be right-sided or bilateral. Cyanotic congenital heart disease is found in approximately 75 percent of the patients with the mirror-image form of right-sided arch, most commonly tetralogy of Fallot, truncus arteriosus and tricuspid atresia.“,6 In patients with a clinically suspected diagnosis of pulmonary stenosis, the presence of a right-sided arch strongly suggests a coexistent ventricular septal defect.7 The most common type of right aortic arch is illustrated by our case. In this type four arch vessels branch, proximally to distally, in the following order: a left common carotid, a right common carotid, a right subclavian and an aberrant left subclavian artery. The latter vessel arises from a conical aortic diverticulum and courses posterior to the esophagus to reach the left arm (Fig. 3). In contrast to the mirror-image form, in this type of right-sided arch, congenital heart disease occurs in only 5 to 10 percent of patients. However, because the ductus arteriosus usually connects either
the aortic diverticulum or the left subclavian artery to the left pulmonary artery, a vascular ring is formed. Trachea-esophageal compression may thus occur, manifested by noisy respiration, recurrent pulmonary infections and dysphagia early in 1ife.s However, three fourths of patients are asymptomatic and do not require surgery. Embryologically the proximal portion of the left aortic arch forms the left common carotid artery and distally persists as an aortic diverticulum, giving rise to the left subclavian artery.4,10 Associated aortic disease and differential diagnosis: Acquired disease of the aorta does not. appear to
R. COMMON CAROTID WITH OLD SURGICAL R. VERTEBRAL R. SUBCLAVIAN
A. OCCLUSION ‘\ A.
ESOPHAGUS ”
TRfICHEA .ID A.
A_ ,L
RECENT
DISSECTION
,_L
AORTIC DlVERTlCULUM
VERTEBRAL
A
SUBCLAVIAN
A.
ARTERIOSUM PULMONARY
OLD
DISSECTION THROMBUS FALSE LUMEN
u
L
RENAL
A.
FIGURE 3. Diagram of the anatomic features found at autopsy. The diverticuium and left subclavian artery coursed posterior to the esophagus. The iigamentum arteriosum connected the diverticulum to the pulmonary trunk and thereby formed a vascular ring. A. = artery; L. = left; Ft. = right.
August 1979
The American Journal of CARDIOLOGY
Volume 44
383
DISSECTION
WITH RIGHT-SIDED AORTIC ARCH-ROAN
ET AL.
occur with increased frequency in patients with a right-sided arch. However, in patients with a left-sided arch and an aberrant right subclavian artery, dissections are known to occur.11J2 In one such case the aortic diverticulum was mistaken for an aortic aneurysm and resected, and the patient died 3 months later from a ruptured suture line. 13 Unnecessary exploratory thoracotomy has been performed when right-sided arches have been mistaken for superior mediastinal masses.7 Right-sided arch and aortic diverticuli thus represent congenital anomalies that can be confused with acquired disease processes. Diagnosis and treatment of aortic dissection: Confusion regarding the anatomy of these congenital anomalies may result in the performance of inadequate diagnostic studies. In our case the initial performance of aortography in a left anterior oblique position re-
sulted in poor visualization of the arch. On subsequent review of these films a diagnosis of aortic dissection could not be excluded with confidence. Later at operation the aortic diverticulum was thought to be involved by the dissection, which necessitated the surgical ligation of the left subclavian artery. This was particularly unfortunate in our case because the right common carotid artery had been ligated previously, and the right subclavian and vertebral arteries, although patent, were compromised by recent dissection. The entire cerebral vascular circulation thus became dependent on the left common carotid artery. Thus, precise definition of the pathoanatomy is essential before a therapeutic program for aortic dissection is begun. If uncertainty exists, repeat aortography and the continuation of aggressive medical therapy may be the best approach.
References 1. Wheat MW Jr: Treatment of dissecting aneurysms of the aorta: current status. Prog Cardiovasc Dis 16:87-101, 1973 2. MacFarland J, WilIerson JT, Dinsmore RE, Buckley MJ, Austen MG, Saunders CA, De Sanctls RW: The medical treatment of dissecting aortic aneurysms. N Engi J Med 286:115-l 19, 1972 3. Sprang DH, Cutler NC: A case of human right aorta. Anat Ret 45: 365-375, 1930 4. SJurford WH, Sybers RG: RigM aortic arch. in, The Aortic Arch and its Malformations. Springfield, IL. Charles C Thomas, 1974, p 52-68 5. Stewart JR, Klncald OW, THUS JL: Right aortic arch: plain film diagnosis and significance. Am J Roentgenoi 97:377-389, 1966 6. Stewart JR, Klncald OW, Edwards JE: An Atlas of Vascular Rings and Related Malformations of the Aortic Arch System. Springfield, IL, Charles C Thomas, 1964, p 8-13, 124-219. 7. Hastrelter AR, d’Cruz IA, Cantez T: Right sided aorta. Br Heart J
384
August 1979
The American Journal of CARDIOLOGY
28:722-739, 1966 8. Klrklln JW, Paciflco AD: Surgical treatment of congenital heart disease. in, The Heart (Hurst JW, ed). New York, McGraw-Hill, 1974, p 779-781 9. Fontana RS, Edwards JE: Congenital Cardiac Disease: A Review of 357 Cases Studied Pathologically. Philadelphia, WB Saunders, 1982 10. Patten BY: Tha development of the heart. In, Pathology of the Heart and Blood Vessels, third edition (Gould SE. ed). Sorinafieid. IL. Charles C Thomas, 1968, p 20 11. Syme J: Aortic dissection involving an aberrant right subclavian artery studied by aortography. Aust Radioi 17: 174- 179, 1973 12. Rbhards WCD, EllIoti CE: Aneurysm of an anomalous right subciavian artery. Br Heart J 19:141-143,1957 13. Shannon JM: Aberrant right subciavian artery with Kommereii’s diverticuium. J Thorac Surg 41:408-4 11, 1961
Volume 44
