Congenital subclavian steal syndrome with anomaly of the aortic arch

Surg Neurol 133 1993 ;39 :133-137

Congenital Subclavian Steal Syndrome with Anomaly of the Aortic Arch Hiroyasu Yamakawa, M .D., Michio Nishikawa, M.D., Ichiro Nakahara, M .D., Shoichi Inagawa, M.D ., Tomoaki Koide, M.D., and Hajime Handa, M .D. Department of Neurosurgery, Hamamatsu Rosai Hospital, Hamamatsu City, Shizuoka, Japan

Yamakawa H, Nishikawa M, Nakahara 1, Inagawa 5, Koide T, Handa H . Congenital subclavian steal syndrome with anomaly the aortic arch . Surg Neurol 1993 ;39 :133-137 .

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A case of congenital subclavian steal syndrome associated with an anomalous right-sided aorta is reported . A 41year-old man complaining of vertigo and a loss of consciousness was admitted. Physical examination revealed a blood pressure differential between the arms that was 20 mm Hg less in the left . Aortography showed a right aortic arch from which arose the right subclavian and both common carotid arteries . The left subclavian artery did not opacify. Right vertebral angiography showed retrograde filling of the left vertebral . A left carotid-subclavian bypass was performed . Postoperatively, the patient is symptom free with equalized blood pressure . Carotid-subclavian bypass ; Right aortic Subclavian steal syndrome KEY WORDS :

arch ;

Congenital subclavian steal syndrome (SSS) is rare, the usual cause being acquired atherosclerotic stenosis or occlusion of the subclavian artery . We report a case of congenital SSS caused by an absence of the left subclavian artery associated with an anomalous right-sided aortic arch and descending aorta.

Case Report A 41-year-old male bus driver presented with a chief complaint of multiple episodies of vertigo and one episode of syncope . He had no past medical history of hypertension or diabetes mellitus . However, he smoked approximately 10 cigarettes a day . He was in his usual state of good health until 1987, when he felt vertiginous while driving his bus . In March 1988, he was evaluated Address reprint requests to : Michio Nishikawa, M .D ., Department of Neurosurgery, Hamamatsu Rosai Hospital, 25 Syogen-cho, Hamamarsu City, Shizuoka prefecture 430, Japan . Received June 18, 1992 ; accepted July 10, 1992 . © 1993 by Elsevler Science

Publishing Co-,

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at another hospital with a brain computed tomographic (CT) scan, which was normal. In October 1988, he began having episodic trouble seeing street signs . In May 1990, he had a brief episode of syncope while driving his bus . On admission, the patient had normal examination of sensorimotor and cranial nerve functions . There were no cerebellar findings and no nystagmus . General physical examination findings included a difference in systolic blood pressure between the arms, the left arm being 20 mm Hg less than the right (left 90/64 mm Hg, right 110/68 mm Hg) . No bruit was audible in the neck or supraclavicular area, and vertigo could nor be induced by changes in head position, neck rotation, or working the upper extremities . Cardiac examination was negative for heart murmur, rub, or gallop . Serum biochemistry, complete blood count, and electrocardiogram were normal . The chest x-ray revealed a probable right-sided aortic arch but no dextrocardia . The tracheal bifurcation was slightly displaced to the left . Esophogram revealed no compression imposed by the great vessels . Aortography revealed a right-sided aortic arch from which the left common carotid arose directly, followed in sequence by the right common carotid and right subclavian (Figure 1) . A well-developed left supreme intercostal artery arising from the descending aorta was present . The left subclavian artery was not visible . Neither carotid artery had abnormal findings . The right vertebral injection showed filling of the left vertebral artery from muscular branches that crossed the midline, resembling a ladder, then retrograde filling into the left subclavian artery (Figure 2) . The intracranial portion of the left vertebral artery was hypoplastic and received blood through an anastomosis from the anterior spinal artery via the posterior inferior cerebellar artery (Figure 3) . A retrograde left brachial arteriogram showed no filling of the subclavian artery proximal to the origin of the vertebral artery . The left subclavian received many networking collaterals from the left supreme intercostal artery (Figure 4) . The retrograde study also revealed a hypoplastic vertebral artery, and many collaterals were 0090-3019/93/36 .00



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Figure 1 . Aortography shows right aortic arch and its branches (LCA,

Yamakawa

of atherosclerosis raised our suspicions of a congenital anomaly of the proximal subclavian . In July 1990, the patient was brought to surgery and placed under general anesthesia with drug-induced hypertension . A left carotid-subclavian bypass was performed using an autologous saphenous vein graft . This was done through a 10-cm incision in the supraclavicular fossa placed parallel to the clavicle . It was necessary to cut the clavicle at its midpoint in order to gain full exposure of the subclavian artery and all its collaterals . A separate incision along the anterior border of the sternocleidomastoid muscle was necessary to expose the left common carotid artery . The distal left subclavian artery was found to be severely hypoplastic, measuring 6 mm in external diameter . After performance of the bypass to establish flow into the subclavian artery, the clavicle was repaired with an internal fixation device . Postoperatively, the arterial blood pressure in the arms equalized . Arteriography of the left carotid showed patency of the graft (Figure 5) . The patient's complaints resolved and he resumed work 7 months after the operation .

left common carotid artery ; RCA, right common carotid artery ; RSA • right Vertebral subclavian artery ; SICA, supreme intercostal artery; RVA, rigEtartery) . No left su r avian is visible.

Discussion seen . There were no abnormal findings on CT of the head . The diagnosis of SSS was made secondary to a nonfilling proximal subclavian artery . The presence of a right-sided aortic arch and the absence of the hallmarks

Figure 2 . Selective right vertebral angiog-

raphy showed subclavian steal from right to left vertebral arteries through the muscle branches . (A) Early phase; (B) delayed phase .

In 1960, Contorni [2] reported the first case of subclavian steal phenomenon but offered no physiologic explanation . The next year, Reivich et al [11] added two cases and explained the phenomenon by the mechanism of



Congenital Subclavian Steal Syndrome

Surg Neurol 135 1993 ;39 : 1 3 3 -137

Figure 4 . Retrograde left brachial angiography showed isolation of left subclavian artery (ISA), Many collateral branches u .ere well developed. and left smbdavian arteryccommunicaeed with descending aorta tDA) through the supreme intercortal artery (SICA) .

Figure 3 . Right selective vertebral angiography revealed left posterior inferior cerebellar artery (PICA) making anastomosis with anterior .rpinalartery (ASA) and bypoplasttc rntracranial portion of left vertebral artery .

cerebral blood steal, in which blood from the one vertebral artery is diverted to the other to perfuse the arm distal to a subclavian artery obstruction . A requisite condition is obstruction or stenosis of the subclavian artery proximal to the origin of the vertebral artery . According to most authorities, almost all of the cases of SSS are secondary to atherosclerotic changes . Few are caused by congenital, traumatic, or iatrogenic origin [14] . Since Massumi [9) reported the first case of subclavian steal associated with right aortic arch and left subclavian artery isolation in 1963, only 39 cases were reported in the literature up to 1982, summarized by Luetmer and Miller [8] . An anomalous right aortic arch is found in one in 1000 persons [61 and thus is not rare . Stewart et al [13] reported that a right aortic arch with a completely isolated left subclavian artery is very rare, a finding in only two of 298 cases .

Theories concerning congenital malformations of aortic arch and great vessels were proposed by Edwards [3] and by Stewart et al [12] . They presumed that many embryologic errors, interruptions, and recombinations were possible with the development and regression of the embryonic double arch system . They classified these malformations into three major types : type 1, divergent aortic arch, or a persistent embryonic circulation ; type 2, a normal left-sided aortic arch that displays a variety of anomalous origins of the great vessels ; and type 3, Figure 5 . Postoperative left common carotid angiography revealed good patency of carotid-subclavian bypass graft (arrow) .



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Figure 6 . Modified schema of double aortic arch theory, introduced by Stewart et al." Regression of shaded portions of the left aortic arch results in isolation of the left suhdavian artery associated with right aortic arch . (a, artery; AA, ascending aorta ; DA, descending aorta .)

right aortic arch, which was further classified into three subclasses-3A, in which the origin of the great vessels is a mirror-image of the normal left aortic arch ; 3B, aberrant left subclavian artery ; and 3C, isolation of the left subclavian artery, in which it is not connected to the aorta . Using the theories of Edwards and Stewart et al, our case was classified as type 3C, in which the defect is explained by an interruption of the left aortic arch between left common carotid artery and left subclavian artery and between left subclavian artery and descending aorta (Figure 6) . A high incidence of congenital heart anomalies also occurs with this condition . Felson and Palayew [4) advocated another clinical category of right aortic arch patterns : type 1, mirrorimage right aortic arch (similar to type 3A of Stewart et al), and type 2, right aortic arch with anomalous origin of the left subclavian artery . According to their investigation, the former is associated with a high rate of congenital intracardiac anomalies, whereas the latter sometimes showed esophageal compression by its vascular ring but rarely heart anomalies . Although our reported case was type 3C of Stewart et al and type 2 of Felson and Palayew, there was no congenital anomaly in the patient's heart and no esophageal stenosis . Despite his anatomical situation, he remained asymptomatic until middle age . Almost all infant cases are associated with congenital heart defects, such as tetralogy of Fallot and/or ventricular septal defect . In most cases, the first symptoms appear in infancy and are related to the cardiac anomaly, not the subclavian abnormality . Luetmer and Miller [81 reported that 23 of 39 patients in their review had congenital heart disease . Adult patients with SSS secondary to the congenital defect usually do not have heart anomalies .

Therefore, they show a different clinical course than those presenting in infancy . Although they have a blood steal phenomenon from the intracranial region to the arm at birth, they do not complain of vertebrobasilar insufficiency or muscle fatigue of their arms . The reasons for the lack of symptoms are speculative, but perhaps younger patients with this condition have cerebral blood flow to the posterior circulation compensated by many collateral branches . With the progression of age, however, intracranial and other collateral arteries undergo sclerotic change, diminishing or obstructing the already marginal blood supply [7] . As for our case, we initially could not deny the assumption that his syndrome was caused by atherosclerosis because of his age of 41 years and his smoking history . Nevertheless, he did not have any past history of hypertension or diabetes mellitus . On angiography, the vessels revealed no stenosis or deformity consistent with atherosclerosis except for obstruction at the origin of the left subclavian artery, but with the congenital aortic arch anomaly, we diagnosed congenital SSS secondary to isolation of the left subclavian artery from the aortic arch . Furthermore, the intracranial portion of left vertebral artery was hypoplastic, making vertebrobasilar insufficiency more easily produced . Thoracotomy is performed for the surgical treatment of congenital SSS . The high association of aortic and intracardiac anomalies necessitates vascular reconstruction and relief of esophageal stenosis from vascular ring formation using this approach, as opposed to a more restricted procedure [5,10,15] . Thoracotomy, however, is not without complications and requires a major operative procedure with a highly advanced support team . Recently, there has been a tendency to apply the transcervical approach in combination with extra-anatomical bypass, an example being the carotid-subclavian bypass . Barnet et al [11 reported that distal carotid flow fell an average of 15% and subclavian flow increased 100% to 400% in their experimental SSS study treated with carotid-subclavian diversion . We used this bypass operation because our patient did not have a congenital heart defect, had the left subclavian artery isolated totally from aortic arch, and had no atherosclerotic findings in the left common carotid artery or in the intracranial anterior circulation .

The authors would like to thank John D . Reeves, M .D., Louisiana State University Medical Center Department of Neurosurgery and C . T. Solomon, M .D ., Johns Hopkins Hospital Department of Neurosurgery, for their help in preparing the manuscript, and Mr . Peter Roth, Zurich University Hospital Department of Neurosurgery for artistic contribution, and Mrs . Susanne Hess for preparing photographs .



Congenital Subclavian Steal Syndrome

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