Radiol Oncol 2006; 40(3): 143-6.
Partial subclavian steal syndrome in a congenitally anomalous subclavian artery
Anton Krnić,1 Zvonimir Sučić,1 Nikša Vučić,2 Ivan Krolo,3
1Department of Radiology, 2Internal Medicine Department, »Holy Ghost« General Hospital, Zagreb, Croatia, 3Department of Radiology, »Sisters of Mercy« Clinical Hospital, Zagreb, Croatia
Background. A subclavian steal syndrome results from the abnormal flow of blood due to the occlusion in
the subclavian artery proximal to the origin of the vertebral artery. A case of a male patient with a partial
subclavian steal syndrome is presented.
Case report. The syndrome was caused by a stenotic lesion of an aberrant right sublcavian artery (the so
called »lusorian artery«). The partial subclavian steal was recognized using the duplex ultrasound which
showed the »to and fro« pattern in the right vertebral artery. Angiography of the aortic arch revealed the
arterial anomaly. In our case, duplex ultrasound was a crucial method in diagnosing the partial subclavian
steal syndrome. However, in order to show the arterial anomaly, the final evaluation had to be performed
using arteriography.
Conclusions. The early recognized partial subclavian steal syndrome provides good understanding of
patient’s symptoms, successful follow up, and a variety of treatment options.
Key words: subclavian artery – abnormalities – radiography – ultrasonography; subclavian steal syn-drome; angiograph y; Doppler duplex; vertebral artery
Introduction                             patients are asymptomatic.1 The syndrome
of subclavian steal caused by an occlusive The most frequent congenital malformation lesion of the aberrant subclavian artery is of the aortic arch branches is the aberrant a rare clinical finding.1-4 This syndrome re-right subclavian artery.1 It is found in 0.5-1% sults from the abnormal flow of blood due of the population.1 Although the compres- to the occlusion in the subclavian artery sion of the oesophagus may occur, most proximal to the origin of the vertebral ar-tery. Blood flow through the vertebral artery Received 23 April 2006                                             is consequently reversed and the subclavian
Accepted 14 May 2006                                              one thus »steals« cerebral blood.
The  syndrome  of  partial  subclavian
Correspondence to: Anton Krnić, MD, Department of Radiology, »Sveti Duh« General Hospital, Sveti Duh 64, HR-10000 Zagreb, Croatia; Fax: +385 1 37 72 136;
E-mail: anton.krnic@zg.t-com.hr                                          literature yet.
steal, caused by the stenotic lesion of the aberrant artery, has not been described in
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Figure 1a. Duplex ultrasound of the right vertebral artery: there is a reverse flow in late systole (the ‘to and fro’ pattern), indicating partial subclavian steal syndrome.
Case report
A 49 year-old man was seen because of dizziness and intermittent paresthesia of the right arm. When he was checked up, there was a blood pressure difference between both arms (right brachial pres-sure 90/60 mmHg, left 120/80 mmHg). Electronistagmography confirmed no ves-tibular lesion.
Duplex scanning showed miscellane-ous plaque of the right internal carotid artery (30% stenosis), with moderately in-creased peak systolic velocity. The right vertebral artery was hypoplastic, with a spectral alteration characteristic for the initial subclavian steal syndrome (the ‘to and fro’ pattern, Figure 1a).5 There were increased velocities and turbulent flow in
Figure 2a. Transcranial continuous waveform Doppler of the left vertebral artery: there is a normal flow pattern, with normal peak systolic velocity (59 cm/s).
Figure 1b. Duplex ultrasound of the right subclavian artery, proximally to the vertebral artery origin: there is a significantly higher peak systolic velocity (231cm/ s), with flow turbulency (filled systolic window), indi-cating stenosis.
the proximal segment of the right subcla-vian artery which suggested significant proximal stenosis of the artery (Figure 1b). The transcranial Doppler also showed a flow asymmetry between right and left vertebral artery. Unlike the left vertebral ar-tery, which showed normal, towards brain directed flow (Figure 2a), the right vertebral artery showed bidirectional flow with de-creased peak systolic velocity (Figure 2b).
The clinical and duplex findings indi-cated the presence of a partial subclavian steal caused by moderate stenosis of the right subclavian artery. Angiography ad-ditionally showed the abnormal origin and course of the right subclavian artery, well known as the »lusorian artery« (Figure 3a, 3b).1-4 It also showed the mild to moderate grade stenosis of the artery in the middle
Figure 2b. Transcranial continuous waveform Doppler of the right vertebral artery: there is a bidirectional flow with reduced peak systolic velocity (19 cm/s).
Radiol Oncol 2006; 40(3): 143-6.
Krnić A et al. / Partial subclavian steal syndrome
14 5
Figure 3a. Digital subtraction angiography of the aor-tic arch: there is an aberrant right subclavian artery, which arises as the most distal vessel from the aortic arch and crosses the middle line. The image provides evidence of a mild to moderate grade stenosis of the aberrant artery in middle line, but there is no clear evidence of steal syndrome.
line (Figure 3a, 3b). It, however, did not provide clear evidence for the presence of the subclavian steal.
Since the patient did not complain of dysphagia, no further evaluation (oesoph-agogram or CT) was done.
The patient was finally released form the hospital and was referred for internist and neurological follow-up.
Discussion
The stenosis of the subclavian artery in our patient was likely the result of progression of an atherosclerotic lesion in the segment of the artery which was in contact with the esophagus.1-4 It resulted in the partial reversal of blood flow in the vertebral artery. The partial reversal of blood flow in our patient could clearly be confirmed only by duplex ultrasound (Figure 1a). It resulted in clinical symptoms known as the partial subclavian steal syndrome.5
Figure 3b. Selective digital subtraction angiography of the aberrant right subclavian artery (lusorian artery).
Unlike us, De Vleeschauwer et al.1, as well as other authors reported patients that had severe stenosis or occlusion of the aberrant subclavian artery and, thus, suffered steal syndrome in its advanced phase, known as the total subclavian steal syndrome. In those patients, the symptoms were much more pronounced and the syn-drome was easier to diagnose using duplex ultrasound or other imaging modalities as
well.1-4
The anomalous origin of the right sub-clavian artery was first reported about 200 years ago by Bayford.6 The anomalous right subclavian artery (»arteria lusoria«) passes behind the oesophagus in about 80% of the cases and in these cases a posterior notch can be seen in oesophagogam and during endoscopy.1,7 The most common symptom is dysphagia, the so-called »dysphagia luso-ria« - dysphagia secondary to a freak of na-ture.8 CT, MR and endoscopic ultrasound help in differential diagnosis.7-9
Treatment options, if indicated, include conservative treatment, surgical treatment, and endovascular treatment, which is re-cently also considered in cases of subcla-vian steal. 1,3,4,7-11
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In conclusion, patients with the luso-rian artery can develop a subclavian steal syndrome, caused by a stentoic lesion of the retroesophageal segment of the aber-rant artery. The subclavian steal can be recognized in its early, partial phase. At that stage duplex ultrasound is the major and usually the only enough sensitive diag-nostic tool. In order to diagnose it, the ul-trasononographer should be familiar with the ‘to and fro’ flow pattern in the vertebral artery.5 Early ultrasonographic recognition of the condition could provide a better, on-time, understanding of patient’s symptoms. In that way, it is possible to plan treatment and follow-up options in a more efficient way.
References
1.   De Vleeschauwer P, Horsch S. Subclavian steal syndrome in a congenitaly anomalous subclavian artery: a case report. Ann Vasc Surg 1986; 1: 389-91.
2.   Rowe DM, Becker GJ, Scott JA, Conces DJ Jr. Right subclavian steal associated with aberrant right subclavian artery. AJNR Am J Neuroradiol 1988; 9: 604-6.
3.   Azakie A, McElhinney DB, Dowd CF, Stoney RJ. Percutaneous stenting for symptomatic stenosis of aberrant right subclavian artery. J Vasc Surg 1998; 27: 756-8.
4.   Basile A, Lomoschitz F, Lammer J. Transbrachial stenting of a critical ostial arteria lusoria stenosis. J Endovasc Ther 2003; 10: 829-32.
5.   Paivansalo M, Heikkila O, Tikkakoski T, Leinonen S, Merikanto J, Suramo I. Duplex ultrasound in the subclavian steal syndrome. Acta Radiol 1998; 39: 183-8.
6.   Bayford D. Account of singular case of obstructive deglutition. Mem Med Soc London 1794; 2: 271-82.
7.   Janssen M, Baggen MG, Veen HF, Smout AJ, Bekkers JA, Jonkman JG, et al. Dysphagia lusoria: clinical aspects, manometric findings, diagnosis, and therapy. Am J Gastroenterol 2000; 95: 1411-6.
8.   Brown DL, Chapman WC, Edwards WH, Coltharp WH, Stoney WS. Dysphagia lusoria: aberrant right subclavian artery with a Kommerell’s diverticu-lum. Am Surg 1993; 59: 582-6.
9.   Maeder M, Binek J. Impact of endoscopic ultra-sonography in the diagnosis of aberrant rightsub-clavian artery: a case report. [German] Ultraschall Med 2004; 25: 296- 8.
10. Pome G, Vitali E, Mantovani A, Panzeri E. Surgical treatment of the aberrant retroesophageal right subclavian artery in adults (dysphagia lusoria). Report of two new cases and review of the literature. J Cardiovasc Surg (Torino). 1987; 28: 405-12.
11.  Vos AW, Wisselink W, Rijbroek A, Avontuur JA, Manoliu RA, Rauwerda JA. Endovascular repair of a type B aortic dissection with transposition of a coexistent aberrant subclavian (lusorian) artery. J Endovasc Ther 2002; 9: 549-53.
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Slovenian abstracts
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Radiol Oncol 2006: 40(3): 143-6.
Sindrom kraje krvi pri prirojeni anomaliji podključnične arterije
Krnić A, Sučić Z, Vučić N, Krolo I
Izhodišča. Sindrom podključnične kraje krvi nastane zaradi motenega pretoka podključnič-ne arterije, ki ga povzroča zapora proksimalno od ustja vratne arterije. V članku opisujemo primer bolnika z delnim sindromom podključnične kraje krvi.
Prikaz primera. Sindrom je povzročila zožitev, ki je nastala zaradi aberantne desne podključnične arterije. Krajo krvi smo prepoznali z dvojnim Doppler ultrazvokom, ki je pokazal značilen vzorec pretoka v vratni arteriji; angiografija aortnega loka pa je pokazala arterijsko anomalijo. Čeprav je bila preiskava z dvojnim Doppler ultrazvokom odločilna, smo arterijsko anomalijo morali potrditi z angiografijo.
Zaključki. Zgodnje odkritje delnega sindroma podključnične kraje krvi nam omogoča, da razumemo vzrok nastanka bolnikovih simptomov ter uspešno sledenje in zdravljenje bolezni.
Radiol Oncol 2006; 40(1): 197-200.