Long-term totally implantable venous access devices (TIVADs) are widely used in clinical practice, particularly in patients requiring frequent venous access such as those receiving chemotherapeutic agents that are either vesicants or unsuitable for peripheral administration. These devices are most commonly used for patients with cancer undergoing chemotherapy to preserve the superficial venous system and improve their quality of life.^(1-4)

The proper functioning of TIVADs depends on accurate catheter positioning and the absence of deformation during use.⁽⁵⁾ To better understand the catheter positioning dynamics, Vesely et al. investigated the behavior of centrally inserted catheters and identified two key anatomical factors that influence tip migration in large-bore catheters placed via the subclavian or internal jugular veins.⁽⁶⁾ First, transitioning from a supine to an upright position results in the elongation of the central veins due to abdominal content displacement, which affects the position of the catheter tip relative to the right atrium.⁽⁶⁾ Second, the caudal displacement of the thoracic wall in an upright posture causes a cranial shift of the catheter tip, pulling it away from the cavoatrial junction.⁽⁶⁾ Studies assessing catheter movement under these conditions have reported changes of up to 3.2 cm,⁽⁷⁾ with greater effects observed in women and obese patients, particularly for larger catheters.⁽⁸⁾

Mammary hypertrophy is a common condition in women characterized by an increase in glandular tissue during puberty or excessive adipose tissue deposition.⁽⁹⁾ This results in increased breast weight and consequent caudal traction on the chest wall.⁽⁶⁾ Based on this observation, it is often hypothesized that patients with mammary hypertrophy may be at a higher risk of catheter tip migration following TIVAD implantation due to enhanced mechanical influence on the thoracic wall when in an upright position.

The objective of this study was to evaluate positional changes in totally implantable venous access devices catheter tips in both supine and upright positions in patients with mammary hypertrophy compared to those without the condition. This study also aimed to determine whether mammary hypertrophy was associated with a greater degree of catheter tip displacement.

The immediate postoperative position of the catheter tip was documented by using a fluoroscopic image obtained at the end of the procedure. A radiopaque ruler was positioned on the surgical table to measure the distance from the catheter tip to the carina in cm (Figure 1).

A total of 116 patients were included in the study. Patient enrolment is detailed in figure 3.

The average patient profile comprised individuals who were approximately 57 years old, overweight, and diagnosed with gastrointestinal neoplasms. The demographic and clinical characteristics of the participants are presented in table 1.

The ICC for catheter tip displacement measurements between Observer 1 and Observer 2 was excellent (r=0.773)⁽¹²⁾ indicating strong inter-observer agreement. The detailed values are listed in table 2.

Regarding catheter tip displacement (Table 3), statistically significant associations were observed with a history of non-deforming thoracic wall surgery (p=0.002) and the presence of a PICC during TIVAD implantation (p=0.042). Mammary hypertrophy was not significantly associated with catheter tip displacement during follow-up (p=0.182).

Mammary hypertrophy, assessed using the Sacchini index, did not significantly correlate with catheter tip displacement (p=0.612).

TIVADs are widely used in patients who require long-term intravenous therapy. When properly implanted and managed, TIVADs are reliable and convenient tools for the prolonged administration of oncological treatments.⁽²⁾ Although techniques for TIVAD placement may vary depending on institutional protocols and patient-specific factors, the distal catheter tip should ideally be positioned at the cavoatrial junction within the superior vena cava.⁽⁵⁾ The reservoir should be anchored to a stable anatomical surface to ensure ease of access and facilitate long-term management,⁽⁵⁾ with the anterior thoracic wall, particularly in the infraclavicular deltopectoral groove, being the preferred site.^(1,13)

The functionality of fully implantable catheters, particularly their ability to deliver medications and aspirate blood effortlessly, depends on proper placement of the reservoir, catheter tip, and subcutaneous tunnel.^(1,14) Despite their clinical utility, TIVADs are associated with complications that can seriously affect both the prognosis and quality of life in patients with cancer.^(1,2,15) Catheter thrombosis and infection are the two main complications associated with these devices, with the migration of the catheter tip acting as a significant risk factor for thrombosis and device malfunction.^(15-17)

According to Vesely et al., in the supine position, mediastinal structures, including the central veins, are compressed by the abdominal contents.⁽⁶⁾ In the upright position, the abdominal contents shift caudally, leading to elongation of the central veins and expansion of the right atrium. Given that the proximal catheter segment remains fixed at the subcutaneous reservoir, this anatomical stretch may alter the position of the distal tip relative to the superior vena cava and the right atrium.^(6,7)

An additional anatomical factor influencing the final position of the catheter tip is the tunnelling and implantation of the subcutaneous reservoir on the anterior thoracic wall. In the upright position, gravitational force causes caudal displacement of the thoracic wall under the influence of gravity.⁽⁷⁾ As the proximal segment is fixed to, this caudal shift can result in a cranial pull on the intravascular catheter tip, displacing it away from the cavoatrial junction.^(6-8)

Contrary to the initial assumptions regarding the influence of breast volume, our analysis demonstrated that previous non-deforming breast surgery and the presence of a PICC at the time of TIVAD implantation were significantly associated with postoperative catheter tip displacement. Prior breast surgery was associated with an average caudal displacement of 23.88 mm, which was potentially related to anatomical alterations in the breast structure (modifying the volume-to-weight ratio) or fibrotic retraction of the thoracic wall. However, this finding should be interpreted with caution, as only four patients in the sample had a history of thoracic surgery.^(6-8)

In contrast, the presence of a PICC at the time of TIVAD placement was associated with a mean cranial displacement of 2.97 mm. This may reflect mechanical interference within the vascular lumen or manipulation during the procedure, both of which can contribute to catheter tip migration.⁽¹⁸⁾

Mammary hypertrophy, as assessed using the Sacchini index, was not significantly associated with postoperative catheter tip displacement. This observation suggests that breast size alone may not be a reliable predictor of catheter movement, potentially due to confounding variables such as breast density, which could affect the gravitational pull on the thoracic wall, independent of volume.

Although our study provided valuable insights into catheter tip displacement after TIVAD implantation, several limitations must be acknowledged. First, it was conducted within a specific patient population and clinical setting, and these findings may not be directly generalizable to other healthcare environments or patient demographics. Second, although the sample size was sufficient for primary comparisons, it may have limited the ability to detect subtle associations. Furthermore, the impact of unmeasured confounding variables and the potential for interobserver variability in distance measurements, despite prior standardization, must be considered. Lastly, although our results revealed statistically significant associations, the clinical relevance and broader implications of catheter tip displacement require further investigation and validation in prospective studies.

Despite these limitations, this study provided valuable insights into a previously unexplored issue in clinical practice. Although we did not observe a higher incidence of catheter tip displacement in patients with mammary hypertrophy, our findings provide a foundation for future research and may serve as a practical reference for guiding future TIVAD implantation strategies. By identifying prior non-deforming thoracic factors associated with catheter tip displacement, this study enhances our understanding of potential risk factors and allows for more informed decision-making regarding catheter tip displacement in clinical settings.

Mammary hypertrophy, as assessed using the Sacchini index, was not significantly correlated with the tip displacement of totally implantable venous access devices.