Optimal catheter tip position of a totally implantable venous access port (TIVAP) is important to maintain its function and to avoid severe complications. In this study, we aimed to assess the reliability of a modified surface measurement method to determine optimal tip position of a TIVAP catheter inserted through the right subclavian vein.Clinical and radiologic information of 105 patients who underwent TIVAP implantation through the right subclavian vein was collected retrospectively. The length of the implanted catheter was determined by a modified surface measurement method, as follows. The distance from the puncture point (point A) to the middle point of the sternal notch (point B), then from the middle point of the sternal notch (point B) to the middle point of Louis angle (point C) was added up. The equation for the catheter length is given by catheter length (cm) = AB + BC + 3. Postprocedure plain chest radiography (CXR) and enhanced chest computed tomography (CT) were used to check the catheter tip position and to calculate optimal position rate. Distance from the carina to the catheter tip and the length of the vertebral body unit were measured on both CXR and CT. Distances from carina to caval-atrial junction (CAJ) and from catheter tip to CAJ were measured on CT.Mean length of the implanted catheter of all patients was 17.0 ± 0.7 cm (male vs female, 17.3 ± 0.5 cm vs 16.7 ± 0.7 cm; P .001). On CXR, a catheter tip located within 2.4 vertebral body units below the carina was identified as the optimal position, and the optimal position rate was 97.1% (102/105 cases). On CT, two definitions of optimal position were used: within 2 cm above or below the CAJ and within 2 cm above or at the CAJ; the optimal position rate was 92.4% (97/105 cases) and 78.1% (82/105 cases), respectively. Median follow-up time was 9.4 months. During the follow-up, no severe cardiac complication was recorded.The modified surface measurement had high reliability in determining the optimal catheter length to accurately place the tip in the superior vena cava near the CAJ.
