Radical Thymectomy With Superior Vena Cava System Reconstruction

Introduction

Invasive thymic tumors with superior vena cava infiltration are rare and aggressive clinical entities.  For these patients, chemotherapy, radiotherapy, or both may be indicated, but when surgical intervention is feasible, en bloc resection of the tumor followed by vascular reconstruction represents the best treatment. Vascular reconstruction can be performed using a venous autograft, an artificial graft such as one made of polytetrafluoroethylene, or a heterologous graft. Venous replacement with autograft gives the best results, but it is not always feasible.  Artificial grafts are widely available but are characterized by a low late patency rate with perivascular fibrosis and collapse. Heterologous patches, such as the bovine pericardial patch, represent the best choice to repair wide vascular loss of substances with good postoperative results and recovery.

Vascular resection and reconstruction of the superior vena cava trunk represents a very challenging surgical intervention linked with high morbidity and perioperative mortality, and it should be performed by experienced surgeons in high-experience centers.

Case Report

A 65-year-old woman was referred to the authors’ department due to clinical manifestations of a superior vena cava syndrome with dyspnea, facial and right arm swelling, head fullness, and cough. She had no signs of myasthenia gravis. A thoracic computed tomography (CT) scan showed an anterior mediastinal mass with vascular infiltration of the left and right brachiocephalic veins and the upper portion of the superior vena cava. An [¹⁸F]fluorodeoxyglucose-positron emission tomography scan demonstrated intense uptake in this lesion and a right video-assisted thoracoscopic surgical biopsy established the histological diagnosis of cortical thymoma.

The patient was started on four cycles of neoadjuvant therapy consisting of cisplatin, doxorubicin, and cyclophosphamide. A postchemotherapy CT scan demonstrated shrinkage of the mass. Preoperative assessments were performed and the authors elected to proceed with radical thymectomy with vascular resection and reconstruction of right and left brachiocephalic veins and superior vena cava.

Surgical Procedure         

This video demonstrates a radical thymectomy for a cortical thymoma with reconstruction of the superior vena cava system using a single bovine pericardial patch.

The CT scan performed after four cycles of neoadjuvant chemotherapy detected shrinking of the mass that still invaded both brachiocephalic veins and the origin of the superior vena cava. The patient was placed supine. Following the skin incision, the sternum was split with a sternal saw and a retractor was positioned to reveal the anterior mediastinum. Radical thymectomy requires resection of the tumor including all the mediastinal fat tissue anterior to the pericardium. A partial infiltration of the upper right mediastinal pleura in this case necessitated its resection. The thymic adipose tissue was dissected to reach the right brachiocephalic vein, which was thus identified and isolated. The right lower thymic pole was resected and the right mediastinal pleura opened to access into the right pleural cavity in order to isolate the arch of the azygos vein. A vascular stapler was used to cut the vein. The superior vena cava was then carefully isolated above the atrial junction. The left brachiocephalic vein was identified and isolated as well. Inspection of the lesion confirmed infiltration of both brachiocephalic veins and of the upper portion of the superior vena cava.

Without any extracorporeal circulation support, all the vessels were cross-clamped. The tumor was resected, with the incision of the venous trunk revealing an endovascular thrombus. The lesion was then carefully removed, sparing the posterior side of the vessels but ensuring macroscopic tumor-negative margins. A single bovine pericardial patch was then shaped and used to reconstruct the superior caval system. A 6/0 continuous nonabsorbable suture was used to stitch the pericardial patch and confer a tubular structure to the graft. Sequential unclamping of the vessels was performed without signs of bleeding or stenosis. Four thoracic drains were positioned in order to evacuate both pleural cavities and the mediastinum. The median sternotomy was closed, and the wound was sutured with intradermal absorbable wires. After five days, a chest CT scan demonstrated the graft’s patency, excluding collapse of the vessel’s graft and the presence of intravascular thromboembolic processes.

Suggested reading

1. Spaggiari L, Leo F, Veronesi G, et al. Superior vena cava resection for lung and mediastinal malignancies: a single-center experience with 70 cases. Ann Thorac Surg. 2007;83(1):223-230.
2. Spera K, Kesler KA, Syed A, Boyd JH. Human aortic allograft: an excellent conduit choice for superior vena cava reconstruction. J Cardiothorac Surg. 2014;9:16.
3. Nakano T, Endo S, Kanai Y, et al. Surgical outcomes after superior vena cava reconstruction with expanded polytetrafluoroethylene grafts. Ann Thorac Cardiovasc Surg. 2014;20(4):310-315.