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Superior Bronchial Artery Arising from the Left Common Carotid Artery: Embryology and Clinical Considerations
Superior Bronchial Artery Arising from the Left Common Carotid Artery: Embryology and Clinical Considerations Philippe Gailloud, MD, Sait Albayram, MD, Don V. Heck, MD, Kieran J. Murphy, MD, and Jean H.D. Fasel, MD A bronchial artery arising from the left common carotid artery was incidentally documented during cerebral angiography in a 64-year-old patient. This variant can be understood as the adult persistence of a primitive bronchial branch arising from the third branchial arch. It represents a potential pitfall for the identification and treatment of the bleeding source in patients with hemoptysis. Index terms:
Arteries, abnormalities
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Arteries, bronchial
J Vasc Interv Radiol 2002; 13:851– 853 Abbreviations:
CCA ⫽ common carotid artery, DSA ⫽ digital subtraction angiography
THE term “superior bronchial artery” describes bronchial artery variants arising from the subclavian or internal thoracic arteries. The clinical relevance of these variants has long been acknowledged in the surgical field, and their importance has been reemphasized recently by the introduction of endovascular therapy for hemoptysis (1). Bronchial arteries of abnormal origin (including from the supraaortic trunks and their branches, the aortic arch, the coronary arteries, or the abdominal aorta) have reported incidences ranging between 16.7% and 30% (2). Among these, the real incidence of superior bronchial arterial variants is not clearly defined yet. Liebow (3) found a 2.7% incidence of bronchial arteries with unusual origin in his anatomic study, most often arising from the innominate and subclavian arteries. Abnormal branches aris-
From the Division of Interventional Neuroradiology (P.G., S.A., D.V.H., K.J.M.), The Johns Hopkins Medical Institutions, 600 North Wolfe Street, Baltimore, Maryland 21287; and the Division of Anatomy (J.H.D.F.), University of Geneva, Switzerland. Received March 6, 2002; revision requested April 19; revision received May 8; accepted May 13. Address correspondence to P.G.; E-mail: [email protected] None of the authors has identified a conflict of interest. © SIR, 2002
ing from the common carotid artery (CCA) include the superior thyroid artery, the lingual artery (sometimes as a common trunk with the former), the ascending pharyngeal artery, and the vertebral artery, the latter usually in association with a contralateral aberrant subclavian artery. We report the incidental angiographic observation of a bronchial artery variant originating from the left CCA.
CASE REPORT Digital subtraction angiography (DSA) was performed in a 64-year-old woman investigated for suspected central nervous system vasculitis. The study was unremarkable; in particular, no angiographic evidence of vasculitis was found. As an anatomic variant, a left bronchial artery was seen originating from the proximal part of the left CCA (Figure). This bronchial artery followed a downward course along the left lateral aspect of the trachea, where it divided into two branches aiming laterally and anteriorly toward the left main bronchus. In addition, a small proximal branch was seen coursing upward and medially along the anterior aspect of the trachea (Figure, part a). Multiple calcified left hilar and mediastinal adenopathies were observed
as well. On a right anterior oblique view, the anomalous branch originating from the proximal left CCA could be seen coursing toward the left hilar lymph nodes, confirming its bronchial nature (Figure, part b).
DISCUSSION Embryology During its initial phase of development, the pulmonary capillary plexus is vascularized by arterial branches derived from the paired dorsal aortas. Later, the newly formed sixth aortic arch and an arterial bud arising from the pulmonary plexus itself connect on each side of the embryo to constitute the definitive pulmonary arteries. The primitive branches that were initially feeding the plexus partially involute to become the adult bronchial arteries. The occurrence of anomalous bronchial arteries from the subclavian arteries or one of their branches (eg, the superior intercostal, internal thoracic, or inferior thyroid arteries) is explained, according to O’Rahilly and colleagues (4), by a developmental mechanism similar to what has been documented for the kidney vasculature. For these authors, the pulmonary anlage is initially fed by a succession of branches arising from the dorsal aorta,
851
852
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Superior Bronchial Artery of Common Carotid Artery Origin
August 2002
JVIR
Figure. Images from a 64-year-old woman with suspected central nervous system vasculitis. (a) Digital subtraction angiography, proximal left common carotid injection, anteroposterior view: the superior bronchial artery (arrowheads) parallels the left main bronchus (L) while a smaller branch (arrow) ascends along the trachea (T). (b) Digital subtraction angiography, proximal left common carotid injection, unsubtracted oblique view: the superior bronchial artery (arrowheads) runs toward the left hilum. Note the presence of several enlarged and calcified lymph nodes in the mediastinum and left hilum (stars).
which appear and involute in a sequential craniocaudal progression. The persistence of one of these early branches results in an anomalous bronchial artery of high origin. Although no definite evidence presently exists to confirm such a mechanism, data derived from comparative anatomy may help corroborate this hypothesis. In several avian species, for example, the bronchial arteries arise from the esophagotracheobronchial branches of the CCA (5). Such a finding suggests that the variant we observed, a bronchial artery arising from the left CCA, could be viewed phylogenetically and ontogenetically as corresponding to a primitive bronchial branch arising from the proximal portion of the third branchial arch (ie, the future common carotid artery).
Clinical Considerations Superior bronchial arteries may occur in association with other pulmonary anomalies or diseases. Bronchial arteries of subclavian origin may, for example, provide collateral supply to the lung in cases of pulmonary artery atresia resulting from failure of development of the sixth arch (6). Cauldwell et al (7) have demonstrated the presence of multiple small anastomotic channels linking the bronchial arteries to the subclavian and internal thoracic arteries. These channels, which seem to account for the “netlike” collateral pathways documented in some cases of pulmonary atresia (8), appear different from the well-defined bronchial arteries of abnormal origin
to which the name “superior bronchial arteries” is usually given. These small collateral channels can probably be understood as remnants of the primitive vascular net that precedes the formation of the definitive pulmonary and bronchial arteries. Such remnants are probably often, if not always, present with subangiographic diameters in most cases. Their secondary enlargement as collateral pathways would then represent a mechanism different from the presence of a bronchial artery of anomalous origin, possibly related to the time at which the collateral supply is established (postnatal period for enlarged “net-like” remnants versus prenatal period for a superior bronchial artery). A combination of both mechanisms may have to
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be considered in our case: the superior bronchial artery of our patient had, apart from its origin, the morphologic appearance of a normal bronchial artery. Conversely, the presence of chronic granulomatous pulmonary disease may have resulted in the secondary enlargement of this superior bronchial artery, which might have otherwise remained angiographically undetectable. It is known that bronchial arteries vascularize the lung lymphatic system, particularly the lymph nodes, and their enlargement in cases of chronic inflammation is therefore not unexpected. To characterize the reported variant as an accessory bronchial artery (ie, present in addition to regular bronchial branches) rather than a superior bronchial artery (ie, replacing regular bronchial artery) would require complete knowledge of our patient’s bron-
Gailloud et al
chial arterial anatomy, which, unfortunately, is not available. Finally, it should be kept in mind that, although rare, a bronchial artery arising from the CCA represents a potential pitfall for identification and treatment of the bleeding source in a patient with hemoptysis. This might be the particular case for patients in whom chronic pulmonary disease has promoted the development of larger superior/accessory bronchial branches. References 1. Remy J, Arnaud A, Fardou H, Giraud R, Voisin C. Treatment of hemoptysis by embolization of bronchial arteries. Radiology 1977; 122:33–37. 2. Sancho C, Escalante E, Dominguez J, et al. Embolization of bronchial arteries of anomalous origin. Cardiovasc Intervent Radiol 1998; 21:300 –304.
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853
3. Liebow AA. Patterns of origin and distribution of the major bronchial arteries in man. Am J Anat 1965; 117:19 – 32. 4. O’Rahilly R, Debson H, Summerfield TK. Subclavian origin of bronchial arteries. Anat Rec 1950; 108:227–239. 5. Abdalla MA, King AS. The avian bronchial arteries: species variations. J Anat 1977; 123:697–704. 6. Tynan MJ, Gleeson JA. Pulmonary atresia with bronchial arteries arising from the subclavian arteries. Br Heart J 1966; 28:573–576. 7. Cauldwell EW, Siekert RG, Lininger RE, Anson BJ. The bronchial arteries: an anatomic study of 150 human cadavers. Surg Gynecol Obstet 1948; 86:395– 412. 8. Allanby KD, Brinton WD, Campbell M, Gardner T. Pulmonary atresia and the collateral circulation of the lungs. Guys Hosp Rep 1950; 99:110 –152.
Arteries, abnormalities
•
Arteries, bronchial
J Vasc Interv Radiol 2002; 13:851– 853 Abbreviations:
CCA ⫽ common carotid artery, DSA ⫽ digital subtraction angiography
THE term “superior bronchial artery” describes bronchial artery variants arising from the subclavian or internal thoracic arteries. The clinical relevance of these variants has long been acknowledged in the surgical field, and their importance has been reemphasized recently by the introduction of endovascular therapy for hemoptysis (1). Bronchial arteries of abnormal origin (including from the supraaortic trunks and their branches, the aortic arch, the coronary arteries, or the abdominal aorta) have reported incidences ranging between 16.7% and 30% (2). Among these, the real incidence of superior bronchial arterial variants is not clearly defined yet. Liebow (3) found a 2.7% incidence of bronchial arteries with unusual origin in his anatomic study, most often arising from the innominate and subclavian arteries. Abnormal branches aris-
From the Division of Interventional Neuroradiology (P.G., S.A., D.V.H., K.J.M.), The Johns Hopkins Medical Institutions, 600 North Wolfe Street, Baltimore, Maryland 21287; and the Division of Anatomy (J.H.D.F.), University of Geneva, Switzerland. Received March 6, 2002; revision requested April 19; revision received May 8; accepted May 13. Address correspondence to P.G.; E-mail: [email protected] None of the authors has identified a conflict of interest. © SIR, 2002
ing from the common carotid artery (CCA) include the superior thyroid artery, the lingual artery (sometimes as a common trunk with the former), the ascending pharyngeal artery, and the vertebral artery, the latter usually in association with a contralateral aberrant subclavian artery. We report the incidental angiographic observation of a bronchial artery variant originating from the left CCA.
CASE REPORT Digital subtraction angiography (DSA) was performed in a 64-year-old woman investigated for suspected central nervous system vasculitis. The study was unremarkable; in particular, no angiographic evidence of vasculitis was found. As an anatomic variant, a left bronchial artery was seen originating from the proximal part of the left CCA (Figure). This bronchial artery followed a downward course along the left lateral aspect of the trachea, where it divided into two branches aiming laterally and anteriorly toward the left main bronchus. In addition, a small proximal branch was seen coursing upward and medially along the anterior aspect of the trachea (Figure, part a). Multiple calcified left hilar and mediastinal adenopathies were observed
as well. On a right anterior oblique view, the anomalous branch originating from the proximal left CCA could be seen coursing toward the left hilar lymph nodes, confirming its bronchial nature (Figure, part b).
DISCUSSION Embryology During its initial phase of development, the pulmonary capillary plexus is vascularized by arterial branches derived from the paired dorsal aortas. Later, the newly formed sixth aortic arch and an arterial bud arising from the pulmonary plexus itself connect on each side of the embryo to constitute the definitive pulmonary arteries. The primitive branches that were initially feeding the plexus partially involute to become the adult bronchial arteries. The occurrence of anomalous bronchial arteries from the subclavian arteries or one of their branches (eg, the superior intercostal, internal thoracic, or inferior thyroid arteries) is explained, according to O’Rahilly and colleagues (4), by a developmental mechanism similar to what has been documented for the kidney vasculature. For these authors, the pulmonary anlage is initially fed by a succession of branches arising from the dorsal aorta,
851
852
•
Superior Bronchial Artery of Common Carotid Artery Origin
August 2002
JVIR
Figure. Images from a 64-year-old woman with suspected central nervous system vasculitis. (a) Digital subtraction angiography, proximal left common carotid injection, anteroposterior view: the superior bronchial artery (arrowheads) parallels the left main bronchus (L) while a smaller branch (arrow) ascends along the trachea (T). (b) Digital subtraction angiography, proximal left common carotid injection, unsubtracted oblique view: the superior bronchial artery (arrowheads) runs toward the left hilum. Note the presence of several enlarged and calcified lymph nodes in the mediastinum and left hilum (stars).
which appear and involute in a sequential craniocaudal progression. The persistence of one of these early branches results in an anomalous bronchial artery of high origin. Although no definite evidence presently exists to confirm such a mechanism, data derived from comparative anatomy may help corroborate this hypothesis. In several avian species, for example, the bronchial arteries arise from the esophagotracheobronchial branches of the CCA (5). Such a finding suggests that the variant we observed, a bronchial artery arising from the left CCA, could be viewed phylogenetically and ontogenetically as corresponding to a primitive bronchial branch arising from the proximal portion of the third branchial arch (ie, the future common carotid artery).
Clinical Considerations Superior bronchial arteries may occur in association with other pulmonary anomalies or diseases. Bronchial arteries of subclavian origin may, for example, provide collateral supply to the lung in cases of pulmonary artery atresia resulting from failure of development of the sixth arch (6). Cauldwell et al (7) have demonstrated the presence of multiple small anastomotic channels linking the bronchial arteries to the subclavian and internal thoracic arteries. These channels, which seem to account for the “netlike” collateral pathways documented in some cases of pulmonary atresia (8), appear different from the well-defined bronchial arteries of abnormal origin
to which the name “superior bronchial arteries” is usually given. These small collateral channels can probably be understood as remnants of the primitive vascular net that precedes the formation of the definitive pulmonary and bronchial arteries. Such remnants are probably often, if not always, present with subangiographic diameters in most cases. Their secondary enlargement as collateral pathways would then represent a mechanism different from the presence of a bronchial artery of anomalous origin, possibly related to the time at which the collateral supply is established (postnatal period for enlarged “net-like” remnants versus prenatal period for a superior bronchial artery). A combination of both mechanisms may have to
Volume 13
Number 8
be considered in our case: the superior bronchial artery of our patient had, apart from its origin, the morphologic appearance of a normal bronchial artery. Conversely, the presence of chronic granulomatous pulmonary disease may have resulted in the secondary enlargement of this superior bronchial artery, which might have otherwise remained angiographically undetectable. It is known that bronchial arteries vascularize the lung lymphatic system, particularly the lymph nodes, and their enlargement in cases of chronic inflammation is therefore not unexpected. To characterize the reported variant as an accessory bronchial artery (ie, present in addition to regular bronchial branches) rather than a superior bronchial artery (ie, replacing regular bronchial artery) would require complete knowledge of our patient’s bron-
Gailloud et al
chial arterial anatomy, which, unfortunately, is not available. Finally, it should be kept in mind that, although rare, a bronchial artery arising from the CCA represents a potential pitfall for identification and treatment of the bleeding source in a patient with hemoptysis. This might be the particular case for patients in whom chronic pulmonary disease has promoted the development of larger superior/accessory bronchial branches. References 1. Remy J, Arnaud A, Fardou H, Giraud R, Voisin C. Treatment of hemoptysis by embolization of bronchial arteries. Radiology 1977; 122:33–37. 2. Sancho C, Escalante E, Dominguez J, et al. Embolization of bronchial arteries of anomalous origin. Cardiovasc Intervent Radiol 1998; 21:300 –304.
•
853
3. Liebow AA. Patterns of origin and distribution of the major bronchial arteries in man. Am J Anat 1965; 117:19 – 32. 4. O’Rahilly R, Debson H, Summerfield TK. Subclavian origin of bronchial arteries. Anat Rec 1950; 108:227–239. 5. Abdalla MA, King AS. The avian bronchial arteries: species variations. J Anat 1977; 123:697–704. 6. Tynan MJ, Gleeson JA. Pulmonary atresia with bronchial arteries arising from the subclavian arteries. Br Heart J 1966; 28:573–576. 7. Cauldwell EW, Siekert RG, Lininger RE, Anson BJ. The bronchial arteries: an anatomic study of 150 human cadavers. Surg Gynecol Obstet 1948; 86:395– 412. 8. Allanby KD, Brinton WD, Campbell M, Gardner T. Pulmonary atresia and the collateral circulation of the lungs. Guys Hosp Rep 1950; 99:110 –152.