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Subclavian-carotid transposition. An option for the surgical management of subclavian artery lesions
(Portuguese PDF version)

Luís Henrique Gil França¹, Caroline Gomes Bredt², Henrique Jorge Stahlke Jr.³

1. Vascular surgeon. Graduate student, Clinical Surgery, Universidade Federal do Paraná (UFPR), Curitiba, PR (Brazil).
2. Vascular surgeon. Former resident at the Division of Vascular Surgery, Hospital de Clínicas, Universidade Federal do Paraná (UFPR), Curitiba, PR, Brazil.
3. Associate professor, coordinator of courses on vascular surgery, Hospital de Clínicas, Universidade Federal do Paraná (UFPR), Curitiba, PR, Brazil.

Correspondence:
Luís Henrique Gil França
Rua Coronel Dulcídio, 1189/1801
CEP 80250-100 - Curitiba, PR, Brazil
Phone: +55 (41) 343.0963
E-mail: luishgf@hotmail.com

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ABSTRACT

Objective: The purpose of this retrospective study was to report our experience in performing subclavian carotid transpositions.

Patients and method: From January 1993 to July 2002, 10 patients underwent subclavian carotid transpositions at the Division of Vascular Surgery at Hospital de Clínicas of Universidade Federal do Paraná (Brazil). The age of the patients ranged from 36 to 75 years, with an average age of 55.6 years. There were six females and four males. Seven patients presented with upper extremity claudication and three with distal embolization. Seven patients had left subclavian artery lesions and three patients had right subclavian artery lesions. All patients underwent arteriography in order to confirm the diagnosis. Surgery was performed using a single supraclavicular incision.

Results: The postoperative result was a significant relief of the symptoms related to subclavian occlusion in all patients. There were no postoperative deaths. No injury to the phrenic, vagal or other peripheral nerves was diagnosed. No postoperative transient ischemic attacks or cerebrovascular accidents occurred. During follow-up, Doppler ultrasound evaluations were performed on all patients to confirm patency and absence of stenoses.

Conclusion: The subclavian-carotid transposition is an effective and relatively easy procedure that avoids the use of prosthetic grafts and obviates the need for a second anastomosis.

Key-words: atherosclerosis, subclavian artery, lesions.
Palavras-chave: aterosclerose, artéria subclávia, lesões.

J Vasc Br 2004;3(2):131-6

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Occlusive atherosclerosis in the supraaortic trunks is a relatively uncommon condition and may present clinical symptoms related to cerebrovascular insufficiency, upper extremity claudication or distal embolization.¹ The first successful reconstruction of an occluded supraaortic trunk using a transthoracic approach was reported by DeBakey et al. in 1958.¹

The improvement of extrathoracic techniques for the correction of subclavian artery lesions evidenced the efficacy and low morbidity and mortality rates of such procedures as compared with the transthoracic approach.^2,3 The advantage of an extrathoracic approach is that it does not require a thoracotomy or sternotomy, which is not indicated especially in the case of elderly or high risk patients. Such techniques include: carotid-subclavian bypass, carotid-axillary bypass, subclavian-subclavian bypass, axilloaxillary bypass and subclavian-carotid transposition.^3,4

Currently, with the development of endovascular techniques, new methods for the management of lesions of supraaortic trunks have achieved satisfactory results.² The objective of the present article is to report our experience with the performance of subclavian-carotid transposition at the Division of Vascular Surgery at Hospital de Clínicas de Curitiba (Brazil).

PATIENTS AND METHOD

The medical records of 10 patients diagnosed with stenosis/occlusion of the subclavian artery were retrospectively reviewed. They had undergone subclavian-carotid transpositions from January 1993 to July 2002 at the Division of Vascular Surgery at Hospital de Clínicas of Universidade Federal do Paraná (Brazil). Demographic and clinical data are listed below in Tables 1 and 2.

Table 1 - Demographic data

Demographic data	Patients
Average age	55.6
Female	6
Smoking habit	8
Hypertension	4
Diabetes	2
Chronic obstructive lung disease	1
Coronary disease	1

Table 2 - Symptoms and clinical signs

Symptoms and clinical signs	Patients
Upper extremity claudication	7
Distal embolization	2
Vertebrobasilar symptoms	1
Dizziness and pain in upper extremity	1

Only the patients with lesions due to occlusive atherosclerosis in the first portion of the subclavian artery were included in the present study. Final diagnosis was established after an arteriography, which evidenced critical stenosis at the origin of the left subclavian artery in six cases and at the origin of the right subclavian artery in three cases. Only one patient presented with complete occlusion of the left subclavian artery. Arteriography confirmed the diagnosis of subclavian steal syndrome in two patients, although only one of them presented with complaints typically associated with this condition. Along with arteriography, Doppler ultrasound exams were performed, which confirmed the lesions in subclavian arteries and revealed absence of lesions in carotid and vertebral arteries (only two patients presented with non-significant bilateral stenosis of the carotid bulb). Patients were referred to surgery due to clinical symptoms related to the subclavian artery lesions found. Asymptomatic patients did not undergo surgery and are currently being followed in the outpatient clinic.

Concerning the surgical technique, all patients were under general anesthesia and the procedure was performed through a transverse supraclavicular incision. The platysma muscle as well as the superficial cervical fascia was dissected and the external jugular vein (which can be ligated if necessary) was exposed. After identifying the phrenic nerve, the anterior scalene muscle was also dissected, paying attention to the thoracic duct to the left. Thus, the subclavian artery was exposed, its branches (dorsal scapular artery, thyrocervical trunk, internal mammary artery and specially the vertebral artery) were identified and their lesions repaired. Internal jugular vein was carefully dissected and retracted laterally in order to expose the common carotid artery (Figure 1). After administering intravenous heparin, the subclavian artery was clamped and sectioned, with its proximal end ligated using a continuous 4-0 prolene suture. Common carotid artery was clamped in order to facilitate the management of the vessels (Figure 2). Then, the distal end of the subclavian artery was anastomosed to the common carotid artery (end-to-side anastomosis) with 5-0 prolene suture (Figure 3). After incision closure, cervical drainage was started and remained for the next 24 hours. In all cases, anatomic and pathological studies were performed, which confirmed that the patients only presented with atherosclerosis in the subclavian artery. During follow-up period, which ranged from six months to eight years, blood pressure rates of both upper extremities were compared and Doppler ultrasound exams were performed in the outpatient clinic of Hospital de Clínicas of UFPR.

Figure 1 - Relation between subclavian artery, common carotid artery and jugular vein.

Figure 2 - Clamping of subclavian artery and arteriotomy.

Figure 3 - Final aspect of the surgery, with subclavian-carotid anastomosis.

RESULTS

The postoperative result was a significant relief of the symptoms related to the occlusion of the subclavian artery in all patients. There was no postoperative mortality. None of the cases involved any lesion to the phrenic nerve, vagal nerve or to any other peripheral nerves; no case of transient ischemic attack or cerebrovascular accident was diagnosed. There was no postoperative complication concerning respiration or surgical wounds (hematoma, lymphatic drainage, infection, among others), and blood transfusion was not needed in any of the cases. The average postoperative hospital stay was three days. During follow-up, which ranged from six months to eight years, Doppler ultrasound exams were performed on all patients, which evidenced patency of the vessels and absence of signs of stenoses; comparing blood pressure rates of both upper extremities, the difference did not exceed 5 mm Hg. There was no late death (30 days after the surgery and during the follow-up period) and no patient was lost during the follow-up.

DISCUSSION

Subclavian artery lesions that require surgical correction are relatively rare, but are more frequent than lesions in innominate artery and common carotid artery.² The left subclavian artery, which is involved in approximately 70% of symptomatic cases, is more frequently affected by atherosclerosis than the right subclavian artery.² It is difficult to estimate the prevalence of isolated occlusion of the subclavian artery because many patients are asymptomatic.² Reasons for the absence of symptoms include the great network of collateral circulation and the slow progress of the occlusion of subclavian artery (which is often benign).³

The symptoms may have a hemodynamic or embolic effect. Contorni reported the "subclavian steal syndrome" (retrograde blood flow in the ipsilateral vertebral artery distal to a proximal lesion) in an asymptomatic patient for the first time in 1960.⁵ These symptoms seem to occur only when exercise of the upper extremity increases the demand for blood flow, leading to a "stealing" from posterior cerebral circulation. Such a syndrome is controversial for many vascular surgeons and does not seem to be a sole indication for surgery.²

Symptomatic lesions are associated with occlusive lesions of vertebral and carotid arteries in 35 to 85% of patients. Generally, it is likely that such injuries lead to vertebrobasilar insufficiency due to the development of atherosclerosis, thrombosis or atheroembolization, associated or not with lesions of vertebral, carotid or innominate arteries. Another syndrome related to proximal subclavian disease is myocardial ischemia in patients who previously underwent internal mammary-coronary artery bypass surgery.^2,4

However, in some cases etiology may not be so evident, especially when lesions in the vertebrobasilar system and carotid arteries are involved, which may mislead one from an accurate diagnosis. Generally, the first indication for patients with vertebrobasilar symptoms and significant lesions in subclavian and carotid arteries is carotid endarterectomy combined with either carotid-subclavian bypass or subclavian-carotid transposition. However, morbidity rate increases in combined procedures due to a higher risk of cerebrovascular accident.^2-4

Parrott was the first to report the transposition of the subclavian artery to the common carotid artery in 1964.⁶ Subclavian-carotid transposition (SCT) turned out to be an effective technique, which avoids the use of prosthetic grafts and requires only one anastomosis. Such a procedure results in a more anatomical arrangement of the vessels. Contraindications are: (1) presence of a graft between the left internal mammary artery and coronary arteries; (2) atherosclerotic lesion extending beyond the origin of the vertebral artery; and (3) origin of the vertebral artery proximal to the lesion.²

The risk of cerebrovascular accident (CVA) seems to be low for patients who underwent SCT. Schardey et al. reviewed the records of 108 patients who had undergone subclavian-carotid transpositions and reported only two cases of transient ischemic attack and no occurrence of CVA. After 70 months of observation, they reported a patency rate of 100%. In this study, there was no postoperative mortality due to CVA.⁷

Several studies evidenced low morbidity and mortality rates and exceptional long-term patency rates. In the present article, there was no mortality and long-term patency was 100%. In a comparison between SCT and carotid-subclavian bypass (CSB), Deriu et al. reported a patency rate of 100% for SCT and of 66% for CSB, concluding that SCT should be the treatment of choice for the management of lesions of proximal subclavian artery.⁸ Cinà et al. referred to higher patency rates and relief of symptoms in patients who underwent SCT.⁹ Edwards et al. argued that SCT should be the treatment of choice for the management of lesions of proximal subclavian artery when compared with other extrathoracic techniques.¹⁰ Van der Vliet et al. found no difference among the procedures analyzed in terms of both morbidity and mortality rates. Patency rates were 100% (10 years after) for SCT, and 62% (five years after) and 52% (10 years after) for CSB.¹¹ Sterpetti et al. compared CSB to SCT as well and found a seven-year patency rate of 100% for SCT and of 85% for CSB.¹² Sandmann et al. reported a mortality rate of 1.4% and a patency rate of 95% analyzing the cases of 72 SCT. Graft thrombosis and distal embolization may explain the difference of incidence of CVA after each procedure.¹³

Currently, with the introduction of endovascular techniques (angioplasty and stent placement), new methods for the management of supraaortic trunk lesions are been developed with satisfactory outcomes, evidencing low morbidity, shorter hospital stay and more successful results.^14-16 Romiti et al. reported that subclavian artery revascularization is effective after surgical procedures as well as after angioplasty; however, they did not include subclavian-carotid transposition in their study.¹⁷ Nevertheless, during follow-up, four-year primary patency rates ranged from 73% to 84%, and secondary patency rates ranged from 90 to 94%. Comparing such data, Ballotta et al. and Cinà et al. suggested that SCT should be the treatment of choice for lesions of the proximal subclavian artery.¹⁸

CONCLUSION

Subclavian-carotid transposition is an effective technique, relatively easy to be performed, which avoids the use of prosthetic grafts and requires only one anastomosis. Such procedure results in a more anatomical arrangement of the vessels, with high patency rates and low morbidity and mortality rates.

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