Approaches and Surgical Techniques for Superior Vena Cava Syndrome

Abstract

The “superior vena cava (SVC) syndrome” results from an obstruction of the blood flow in the SVC due either to an external compression by a (tumoral) mass located in the mediastinum or to an intra-vascular thrombosis. Two types of SVC syndromes exist: the acute and the chronic forms. These conditions differ by the symptoms that they cause, which are related to alternate drainage pathways that may or may not have the time to develop. From a pathophysiological point of view, the SVC syndrome results in increased venous pressure in the upper part of the body, which causes facial, conjunctival swelling and head cyanosis, especially when patients lay down. In cases of acute SVC syndrome, venous return from the upper part of the body is compromised and swelling of the head is very important. Hemodynamic instability is frequent, mostly due to the absence of collateral drainage. In situations of chronic SVC obstruction, symptoms of swelling are less common and hemodynamic instability is rare, even in presence of hypotension, because the venous return to the heart is possible through collateral drainage. Therefore, with these differences in mind, the strategy for SVC obstruction management will be different. Causes of SVC obstruction are generally linked to SCLC, NSCLC, lymphoma and mediastinal diseases. Their management is decided in a multidisciplinary fashion and include a combination of systemic therapy, radiation therapy, endovascular stenting when indicated and/or surgical resection and reconstruction . Total SVC clamping to perform the surgical intervention should be limited in time to avoid cerebral edema, decreased venous return and patient hemodynamic instability. Various methods to avoid the physiopathological effects of SVC clamping have been described including jugulo-femoral bypasses, intra-field bypasses and catecholamine administration. These methods allow safe and efficient shunting during the period of SVC replacement. Most complications observed following SVC surgery are respiratory or thrombotic events. Thus, cases requiring SVC resection should be discussed to ensure that the risk sustained for venous replacement will be balanced by a real oncological benefit.