Ann Thorac Surg 2000;70:856-858
© 2000 The Society of Thoracic Surgeons
Original articles: cardiovascular
Safety of left innominate vein division during aortic arch surgery
Chitoor B. Sai Sudhakar, MDa,
John A. Elefteriades, MDa
a Section of Cardiothoracic Surgery, Yale University School of Medicine, New Haven, Connecticut, USA
Address reprint requests to Dr Elefteriades, Section of Cardiothoracic Surgery, Yale University School of Medicine, 333 Cedar St, New Haven, CT 06510
e-mail: john.elefteriades{at}yale.edu
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Abstract
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Background. The surgical approach to the aortic arch via median sternotomy can be hindered by the left innominate vein (LIV). Retraction of the LIV may injure the vein. The safety of LIV ligation has been controversial. Opinion has also differed regarding whether a divided vein should be reanastomosed after arch replacement is completed. We report our experience with division and ligation of the LIV for improved aortic arch exposure and facilitated excision of mediastinal tumors.
Methods. From January 1996 to June 1998, the LIV was divided and ligated in 14 patients (8 men, 4 women) after consideration of local anatomy, adequacy of aortic arch exposure, level of distal aortic anastomosis, and in case of mediastinal tumors, extent of involvement of mediastinal structures. The LIV was divided between clamps, doubly ligated, and the ends oversewn. Patients were assessed at 1 month and at yearly intervals for upper extremity edema and neurologic symptoms.
Results. In 12 patients LIV division improved aortic arch access, and in 2 patients, it facilitated excision of mediastinal tumors. The mean age of patients was 56 years (range 22 to 80). Follow-up ranged from 1 week to 30 months. All patients had left upper extremity edema for 7 to 10 days, which resolved with arm elevation. One early patient required reexploration for bleeding from the LIV stump. One patient died because of multiorgan dysfunction. None had any residual left upper extremity edema or neurologic symptoms.
Conclusions. We conclude that, although not uniformly or commonly necessary, division of the LIV can safely be utilized to facilitate aortic arch exposure without significant long-term morbidity. LIV reanastomosis is not necessary.
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Introduction
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It is an established principle of surgery that good exposure and visualization are prerequisites for the meticulous performance of surgery. In aortic surgery, excellent proximal and distal exposure and control are necessary for performing safe anastomoses. The surgical approach to the distal ascending aorta and aortic arch via a median sternotomy can be hindered by the left innominate vein (LIV). Retraction of the innominate vein is tedious and may injure the vein, causing either an immediate or delayed hemorrhage. Surgeons have recognized the exposure advantages of LIV division, but have had lingering concerns about the safety of this division. In particular, concerns have centered around impaired venous return from the arm and the brain and the potential consequences of venous hypertension in the arm and brain. Ligation of the innominate vein after penetrating injuries of the thoracic cavity and accidental injury has been described [1]. We report our experience with planned division and ligation of the left innominate vein to improve exposure of the aortic arch and to facilitate the excision of mediastinal tumors.
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Material and methods
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From January 1996 to present, the left innominate vein was divided and ligated in 14 patients. The decision to divide the innominate vein was made intraoperatively after careful consideration of the anatomy, the level of the distal aortic anastomosis, and in the case of mediastinal tumors, the extent of involvement of the thoracic structures. Postoperatively, in relation to this study, the patients were initially assessed at 1 month for upper extremity and neurologic symptoms and subsequently at yearly intervals.
None of these patients had retrograde cerebral perfusion, which we use infrequently at our institution. Elevation of the head of the bed was done as soon as possible postoperatively in the intensive care unit to minimize cerebral edema. We use elevation of the head of the bed routinely in other patients as well, for the psychological and pulmonary benefits.
Surgical anatomy
The innominate veins are formed behind the sternoclavicular joints by the confluence of the internal jugular and subclavian veins. After its formation by the confluence of the left subclavian and the left internal jugular vein behind the left sternoclavicular joint, the left innominate vein courses transversely across the aortic arch and the proximal portions of the arch vessels (brachiocephalic trunk, left common carotid artery, and left subclavian artery) to join the right innominate vein to form the superior vena cava at the lower border of the first right costal cartilage. During their course, the innominate veins receive the superior intercostal veins, the internal mammary veins, the inferior thyroid veins, the vertebral veins, and other smaller tributaries from the thymus and the surrounding structures. Distortions of the normal anatomy occur in the presence of an expanding aneurysm or dissection of the ascending aorta within the confines of the anterior mediastinum, causing a cephalad shift of the aortic arch deep to the left innominate vein.
Surgical technique
After a median sternotomy is performed, the pericardium opened, and the thymus divided, the left innominate vein is mobilized away from the aortic arch with a combination of blunt and sharp dissection. The vein is also freed for a distance of 1.5 cm on either side of the midline (Fig 1). The left innominate vein is divided between clamps, ligated and suture-ligated with silk, and the ends oversewn with 5/0 Prolene to ensure absolute hemostasis, even in the face of the sudden variances in intrathoracic pressures (eg, coughing and straining) anticipated in the postoperative period. One of the early patients in this series bled through an intact ligature and suture ligature, requiring reexploration. The oversew suturing was added after that case.
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Fig 1. Divided innominate vein, improving exposure of aortic arch and its great branches. (Ligatures are simplified for clarity.) Ligature, suture ligature, and oversew stitch are used for security (see text).) Collaterals through intracranial communications, mammary veins, azygous and hemiazygous systems, and mediastinal veins provide venous drainage after division.
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Results
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The left innominate vein was divided in 14 patients between January 1996 and May 1998. This procedure was carried out in 12 patients for improved access to the aortic arch for procedures on the ascending aorta or aortic arch or both. Two other patients required division of the innominate vein to facilitate adequate excision of mediastinal tumors. The mean age of the patients, 4 women and 8 men, was 56 years (range 22 to 80). The follow-up period ranged from 1 week to 30 months.
All patients were extubated within the first 24 hours, and all awoke before the first postoperative morning. No patient had a postoperative stroke.
All patients had edema of the left upper extremity for 7 to 10 days, which resolved with elevation of the arm. Patients were followed up clinically only, without measurement of venous pressures in the left jugular or subclavian veins. In this series, 1 patient died during the perioperative period owing to multiorgan dysfunction after a prolonged hospital course. No patient had any residual edema or difficulty using the left upper extremity during the entire follow-up period. In addition, none of the patients had any neurologic symptoms.
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Comment
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Division of the LIV provides excellent exposure of the aortic arch and the proximal portions of the arch vessels. In addition, it prevents excessive traction on the vein and avulsion injury away from the exposed portion of the vein, which is difficult and cumbersome to repair. Additionally, optimal exposure of the branches of the aortic arch facilitates clamping of the head vessels to avoid embolization of air or particles during deep hypothermic circulatory arrest [2]. Such exposure also facilitates selective cerebral perfusion via the head vessels as well as individual grafting of the head vessels, a procedure enjoying renewed popularity with the availability of preformed aortic arch grafts. This report confirms the safety of dividing the LIV to optimize exposure of this area. We take meticulous care to secure the innominate vein and reinforce the ligation by oversewing the cut ends with fine suture. We adopted this rigorous policy to avoid late bleeding, possible under high venous pressures such as during coughing or Valsalva maneuvers.
Although subclavian vein occlusion can lead to prolonged edema of the arm, internal jugular vein ligation in head and neck surgery is without neurologic consequences. When the LIV is interrupted, blood is returned to the right side of the heart via the azygous/hemiazygous systems, the internal mammary veins, the lateral thoracic and superficial thoracoabdominal veins, and the vertebral venous plexus [3]. In addition, others have demonstrated that the venous return from the left subclavian vein may pass through the left internal jugular vein (with reversal of flow in the left internal jugular vein), then through the transverse sinus in the cranium and into the right atrium, via the right internal jugular vein [4].
As anticipated, all our patients developed early arm edema, which was managed by elevation of the upper extremity. The absence of neurologic symptoms was also predictable in view of the adequate collateralization of the brain via the intracranial venous pathways and the routes noted above. One patient in this series died because of multiorgan dysfunction, and division of the innominate vein did not contribute to her death. None of the patients in this series required prolonged hospitalization for causes attributable to this procedure. In addition, follow-up assessment did not reveal any arm or neurologic symptoms.
When retrograde cerebral perfusion during deep hypothermic arrest is anticipated, we recommend avoiding innominate vein ligation, as specific dangers in this setting are unevaluated.
Most aortic operations can be performed without dividing the innominate vein. In selected cases, however, such division can be technically useful, improving exposure and avoiding traction avulsion of the vein from the superior vena cava. On the basis of our experience with this series of patients, we conclude that division of the LIV is a safe procedure and does not carry any long-term morbidity. Reconstruction of the vein at the completion of the procedure is not necessary. Division of the LIV is recommended as an adjunct to improve exposure, when necessary, in ascending, arch, and great vessel surgery, as well as to facilitate en-bloc resection of aggressive anterior mediastinal tumors.
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References
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Mattox K.L. Thoracic great vessel injury. Surg Clin North Am 1988;68:693-703.[Medline]
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Elefteriades J.A. Brain protection during aortic surgery. American Association of Thoracic Surgery—adult postgraduate course. New Orleans, LA: American Association of Thoracic Surgery, 1999.
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Bashist B., Parisi A., Frager D.H., Suster B. Abdominal CT findings when the superior vena cava, brachiocephalic vein or subclavian vein is obstructed. Am J Roentgenol 1996;167:1457-1463.[Abstract/Free Full Text]
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Yonei A., Sari A. Reversal of blood flow in the internal jugular vein. Anesthesiology 1991;74:634-635.[Medline]
Accepted for publication March 8, 2000.
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Abstract
Introduction
