Comparison of radiographic landmarks and the echocardiographic SVC/RA junction in the positioning of long-term central venous catheters

Background: When implanting a permanent central venous catheter, the usual aim is to place the tip at the superior vena cava/right atrial (SVC/RA) junction. However, data validating radiographic landmarks of the SVC/RA junction are limited. This investigation was undertaken to compare the radiographic landmarks with the SVC/RA junction as determined by transesophageal echocardiography (TEE). Methods: In 20 adult oncologic patients undergoing implantation of a permanent subcutaneous central venous catheter, the catheter tip was placed in the SVC/RA junction under TEE guidance. The position of the catheter tip on chest X-ray, which represented the echocardiographic SVC/RA junction, was then compared with a standard radiographic landmark of the SVC/RA junction and with thoracic vertebral levels. Results: In all but two patients radiographic SVC/RA junctions were identified. The echocardiographic SVC/RA junction ranged from 0.6 cm above to 2.8 cm below the radiographic SVC/RA junction. There was a significant difference between the distance from the carina to the radiographic SVC/RA junction and the distance from the carina to the echocardiographic SVC/RA junction. The thoracic vertebral body correlating with the echocardiographic SVC/RA junction ranged from the sixth to the ninth level. Conclusion: Both the radiographic SVC/RA junction and the thoracic vertebral bodies are not reliable landmarks for the SVC/RA junction defined by TEE. Physicians should be aware that using the radiographic SVC/RA junction to confirm proper positioning of permanent central venous catheters risks placing the catheter tip in the upper SVC, with subsequent potential long-term complications. More reliable radiographic landmarks for the SVC/RA junction should be investigated.