The Superior Vena Cava (SVC) is the main blood vessel that transports de-oxygenated blood from the upper body to the heart.
The SVC is a short vein located in the anterior right Superior Mediastinum, which is the area found in the mid-line of the Thorax (Drake et al. 2010). The vein is surrounded by many structures involved in the respiratory and circulatory system including the right Bronchus and the Mediastinal lymph nodes (Martini & Ivonne 2004). Figure 1 is a coronal CT image of a human chest, highlighting the heart and the location of the SVC. Superior Vena Cava Syndrome (SVCS) is characterised by the obstruction of blood flow through the SVC (Cohen et al. 2008). As the vein is relatively thin walled, obstruction …show more content…
Although cancer has been the most common etiolgoy in the past, complications in the use of intravascular catheters, pacemakers and defibrillators are becoming a more common cause of SVCS. Recent research has suggested that use of such structures have been linked to blood clots in the SVC (Chee et al. 2007).
Disruption of the Endothelium of the SVC through trauma from the lead in such structures is thought to be a cause of blood clot formation in the vein as the mechanical stress can trigger the inflammatory response (Kokotsakis et al. 2014). The SVC – atrial junction is often the main site of thrombosis as the lead of the structures bends around the junction and when fibrin becomes deposited on the surface of the structure, it can become incorporated into the tunica intima of the vessel which can cause inflammation and result in thrombosis (Chee et al. 2007).
Both of the above cause inadequate blood return to the heart from the upper body. This makes it difficult for the heart to pump enough oxygenated blood around the body and therefore the metabolic requirements of the body cannot be met. The blockage in the SVC results in blood backing up and causing swelling in the upper