Management of Venous Access Ports with Varying Maintenance Intervals after Chemotherapy for Malignant Tumors

Totally Implantable Venous Access Ports (TIVAP) are a closed intravenous infusion system that is completely implanted in the body. It was first reported to be used by Niederhuber JE in 1982¹. TIVAP can be used for the infusion of various high-concentration chemotherapy drugs, total parenteral nutrition solutions, as well as for blood collection and transfusion, etc. It reduces the irritation of drugs on patients' blood vessels and alleviates the pain caused by repeated venipuncture. Its daily management and maintenance are convenient, and it provides good comfort, making it one of the first choices for the venous access in the treatment of malignant tumor patients². However, due to the high cost of TIVAP and the fact that it is currently still at patients' own expense, most patients choose to keep TIVAP during the non-treatment period after completing the phased cycle of anti-tumor treatment in case of disease recurrence and the need for reuse³. Thiel K⁴ followed up 1005 tumor patients with implanted TIVAP and found that 11.94% (120/1005) of the patients had related complications. Although compared with previous infusion methods such as PICC and CVC, the incidence of complications is lower and the indwelling time is longer^5,6, related complications are still unavoidable. TIVAP complications include port-related bloodstream infections, catheter-related thrombosis, catheter blockage, pinch-off syndrome, port body flipping, catheter detachment, and other complications^7,8. The occurrence of complications will lead to the delay of patients' treatment. In severe cases, it will affect patients' psychology and disease prognosis, causing physical and mental harm to patients and their families, and an increase in medical expenses⁹. The maintenance of implantable venous access ports involves assessing the functional status of the port catheter, replacing non-coring needles and dressings, and performing timely flushing and sealing of the catheter¹⁰. To ensure the optimal performance of TIVAP in patients' bodies, regular maintenance is necessary to maintain the patency of the infusion path, ensure the device's normal operation, and help extend its service life, thereby preventing and reducing the occurrence of adverse events such as catheter blockage.

There is still controversy regarding the maintenance interval of TIVAP during the non-chemotherapy period. Clinical studies have shown^11,12 that the shorter the maintenance cycle of TIVAP during the non-treatment period is, the lower the risk of catheter blockage will be. At present, most studies recommend maintenance once every 4 weeks, mainly to prevent catheter blockage¹³. However, relevant studies reported in recent years¹⁴ showed that there is no direct relationship between the length of the maintenance interval and the blockage of the TIVAP catheter, but there are relatively few studies on malignant tumor patients. Due to the existence of cancer procoagulant in malignant tumor cells, which secrete mucin and tissue factor, resulting in an increase in blood viscosity, and combined with the fact that TIVAP needs to be indwelling in blood vessels for a long time, compared with other patients, it is extremely easy to form thrombosis at the top of the catheter. Compared with the conventional 4-week maintenance interval, extending the maintenance interval of Totally Implantable Venous Access Ports (TIVAPs) to 8-12 weeks can reduce the frequency of patients' hospital visits and alleviate their economic burden. However, cancer patients often present with a hypercoagulable state after chemotherapy, and there is still a lack of targeted verification regarding whether such an extended maintenance scheme is applicable to this specific population. The core of the current clinical controversy over TIVAP maintenance intervals during the non-chemotherapy period lies in the absence of clear definitions for the scheme's applicable scenarios, operational standards, and scope of limitations. Although existing studies have mentioned the feasibility of extended intervals, they have not clarified whether this approach is exclusively applicable to the non-treatment phase following chemotherapy completion. Meanwhile, the standardization level of maintenance operations has not been specified in conjunction with the interval schemes.

This study intends to address the aforementioned issues in a targeted manner. First, the research scenario is strictly limited to the non-treatment period of malignant tumor patients after chemotherapy, excluding patients who require frequent TIVAP use during chemotherapy. Second, the clinically routine 4-week interval is clearly set as the control group, while two experimental intervals (8 weeks and 12 weeks) are simultaneously included, and the core maintenance operation standards are unified. This study aims to compare the application value of TIVAP management schemes with different maintenance frequencies in patients with malignant tumors after completing chemotherapy, explore the factors associated with infusion-related complications, provide a scientific basis for clinical practice, and identify the most suitable TIVAP maintenance strategy for this patient population.

This study has been approved by the Ethics Committee of The First Affiliated Hospital of Jinan University (Guangzhou Overseas Chinese Hospital; Approval No. SYJS2024-05-22-09). Before enrollment, all patients were informed of the study objectives, protocol, and potential risks by trained research nurses. After fully understanding the information, each patient signed the Informed Consent Form; for patients unable to sign independently, their legal guardians signed the Proxy Informed Consent Form on their behalf. The equipment and software used are listed in the Table of Materials.

1. Sample size estimation

The sample size was calculated using the formula for a multi-group equal design:

​where, k = number of groups; Z values are the standard normal deviates for type I error and power; s is the estimated standard deviation; and µ_i = and µ denote the mean outcome for group i and the overall mean, respectively.

For this study, k = 3, two-sided α = 0.05 (Z_1-α/2 = 1.96), and power = 0.90 (Z_1-β = 1.28). Based on pilot data, s = 0.15. Substituting these parameters yielded an estimated n = 95 per group, giving a minimum total sample size of 285. Allowing for a 10% dropout rate, at least 106 patients were required per group, with a final target enrollment of ≥318 patients. The study workflow is illustrated in Figure 1, which structures the research into 5 phases: Enrollment: 350 initial patients were screened, with exclusions detailed in the next module. A total of 303 patients were finally included and completed the follow-up. The discrepancy in sample size (15 cases less than the initial estimate) was attributed to the following reasons: 10 patients withdrew due to adjustments in their chemotherapy regimens after enrollment, and 5 patients were lost to follow-up. All withdrawals and losses to follow-up occurred within 12 weeks of enrollment, and the loss-to-follow-up rates were balanced across the three groups (Group A: 3.1%, Group B: 4.9%, Group C: 4.8%), with no selective bias observed. Grouping: Patients chose maintenance intervals (4-week/8-week/12-week) per preference, forming Groups A/B/C as shown. Intervention & Outcomes: Six key endpoints were compared, using: Wells score for thrombosis; SF-36 questionnaire for quality of life. Complication Analysis: Unifactor/multifactor models identified predictors as visualized. Targeted measures and study findings were derived, with all steps traceable to Figure 1.

2. General information

A total of 303 patients with malignant tumors who underwent implantation of a venous access port in our hospital between June 2021 and June 2023 were enrolled. Inclusion criteria were: (1) confirmed diagnosis of malignant tumor requiring chemotherapy; (2) successful implantation of a venous access port; and (3) ability to provide informed consent and comply with follow-up. Exclusion criteria were: (1) severe coagulation disorders; (2) active local or systemic infection at the time of implantation; (3) previous history of central venous catheter-related complications; or (4) refusal to participate.

Patients were allocated to three groups according to their preferred port management frequency: Group A (high-frequency maintenance, n = 97), Group B (medium-frequency maintenance, n = 101), and Group C (low-frequency maintenance, n = 105). Clinical outcomes among the three frequency-management strategies were compared over a 48-week follow-up period after port implantation. Maintenance was considered timely if the actual visit date differed from the scheduled interval by no more than 1 week.

For safety evaluation, complications were defined as catheter occlusion, infection, thrombosis, bleeding, or mechanical dysfunction occurring during the maintenance period. Patients were further categorized into a complication group and a non-complication group to identify risk factors for adverse events associated with venous access ports in chemotherapy-treated patients.

3. Management of implantable venous access ports

1. Contraindications for implantation
   All 303 patients included in this study were implanted with the same brand and model of totally implantable venous access port (TIVAP) system. Implantation was permitted if platelet count was ≥50 × 10⁹/L, international normalized ratio (INR) ≤1.8, and activated partial thromboplastin time (APTT) ≤1.3-fold of the normal value, without the need for pretreatment reversal. If the platelet count was <50 × 10⁹/L, INR >1.8, or APTT >1.3-fold of normal, coagulation dysfunction was corrected before surgery. Severe coagulation disorders not correctable by medical intervention were considered an absolute contraindication due to the risk of uncontrollable bleeding.
2. Preoperative preparations
   1. Informed consent
      Patients were informed of procedural risks, intraoperative precautions, postoperative care, potential complications, and associated costs. Written informed consent was obtained.
   2. Preoperative examinations
      Routine blood counts, liver and kidney function, coagulation profile, and electrolytes were assessed. Electrocardiography and ultrasound of the carotid vein and superior vena cava were performed to confirm vascular patency.
   3. Components of the totally implantable venous access port (TIVAP) system, ultrasound equipment, surgical instruments, sterile surgical drapes and dressings, anesthetic drugs, 100 IU/mL heparin sodium dilution, 0.9% sterile sodium chloride injection, and catheter tip positioning device.
3. Approaches for implantation
   ​The implantation standards for infusion ports refer to the Shanghai expert consensus on totally implantable access ports¹⁵. Two common approaches were used: arm ports and chest wall ports.
   1. Arm port implantation
      ​Patients were placed supine with the ipsilateral arm abducted. After disinfection and sterile draping, the basilic or axillary vein (upper third of the arm) was punctured under real-time ultrasound guidance. A guidewire was inserted, followed by advancement of the sheath and catheter. The catheter was guided across the sternoclavicular joint into the superior vena cava. Position was confirmed, and a subcutaneous pocket was created on the medial aspect of the upper arm. The port body was connected and secured in the pocket, and the incision was closed. The catheter was locked with 5 mL of heparinized saline (100 IU/mL).
   2. Chest wall port implantation
      Patients were placed supine, with landmarks identified on the chest wall. After local anesthesia, the internal jugular or subclavian vein was punctured under ultrasound guidance. The catheter was advanced along a guidewire, and a pocket was created in the subclavicular region. Using a tunneling device, the catheter was guided to the chest wall incision, connected to the port body, and secured. The incision was sutured, and the catheter was locked with 5-10 mL of heparinized saline (100 IU/mL).
      The three groups were assigned strictly in accordance with the access site stratification principle: specifically, within the 4-week, 8-week, and 12-week groups, the sample proportions of upper arm ports and chest wall ports showed no significant difference from the distribution in the total sample. This design aimed to avoid interference from uneven access site distribution in the evaluation of maintenance efficacy and complications.
4. Maintenance procedures
   Aseptic techniques were strictly followed by nurses. The skin around the TIVAP was cleaned and disinfected using 75% ethanol and 2% chlorhexidine gluconate. Blood was aspirated from the catheter to check for smooth blood return. A 20 mL volume of 0.9% sterile sodium chloride injection was used for pulsatile flushing. This volume of flushing solution creates intraluminal turbulence, enabling thorough removal of residual medication from the inner wall of the catheter¹⁶. Finally, 5 mL of 100 IU/mL heparin sodium dilution was used for positive-pressure capping: the 100 IU/mL concentration can maintain an anticoagulant effect in the catheter lumen for 7-14 days, and the total dose of 5 mL is far below the daily safe dose for adults (≤10,000 IU), with no increased risk of bleeding¹⁷.
   For patients who developed adverse complications during treatment, nurses provided targeted interventions and conducted patient education: (1) For patients with loose skin, when turning over or lifting the operative-side arm significantly, they were instructed to gently press the TIVAP reservoir with the contralateral hand to enhance fixation; (2) For patients with excessive chest wall mobility, education was provided to advise them to avoid strenuous movements in daily activities that might increase pressure on the skin over the TIVAP pocket; (3) For patients with excessive movement during sleep, nurses could consider using a restraint strap if necessary.
5. Patient education and management schemes
   The nursing staff distributed educational materials and explained key self-observation points. Patients were taught to recognize early symptoms of complications (local redness, swelling, pain, exudation, fever) and instructed to seek medical care for catheter breakage, detachment, or severe bleeding.
   ​Patients were scheduled for hospital-based maintenance at different intervals: every 4 weeks (Group A), every 8 weeks (Group B), or every 12 weeks (Group C). Patients were also guided to perform home self-monitoring for skin changes around the port.
6. Safety precautions and waste disposal
   1. Heparin handling
      Heparinized solutions were prepared in sterile conditions, with attention to dosage accuracy to prevent bleeding or thrombosis. Any signs of bleeding or thrombotic complications were monitored and documented.
   2. Restraint belt policy
      Use was restricted to patients with excessive movement, applied only with informed consent and continuous monitoring.
   3. Waste disposal
      Sharps (needles, guidewires) were discarded in puncture-proof containers. Blood-contaminated dressings and heparinized waste were disposed of as biohazard materials in accordance with institutional biosafety protocols.

4. Observation indicators

Patients' baseline data were collected at enrollment, including age, sex, body mass index (BMI), tumor type, metastatic status, comorbidities (chronic diseases were defined as long-term conditions such as hypertension, diabetes, coronary heart disease, and chronic obstructive pulmonary disease), and type of venous access port. Laboratory results at admission were also recorded, including platelet count, white blood cell count, neutrophil count, and serum albumin level. The observation period was 48 weeks after port implantation. Outcomes included thrombosis risk, catheter patency, complications, quality of life, management satisfaction, compliance, and cost of maintenance.

1. Thrombosis risk
   The Wells score for deep vein thrombosis (DVT) was applied¹⁸. Patients with a score ≤0 were classified as low-risk, those with scores of 1-2 as moderate-risk, and those with scores ≥3 as high-risk. If both lower limbs presented symptoms, the limb with the more severe manifestations was used for evaluation.
2. Catheter patency
   Patency was defined as visible blood reflux on aspiration and unobstructed flushing of the catheter. "Withdrawal obstruction" was defined as the absence of blood reflux, regardless of whether flushing was smooth.
3. The diagnosis of suspected complications was made by 2 vascular surgeons. After a patient developed suspected complications, the surgeons conducted a comprehensive assessment based on clinical symptoms, imaging examinations (ultrasound/CT angiography [CTA]), and laboratory results (complete blood count [CBC], secretion culture).
   1. Catheter pinch-off (Pinch-Off Syndrome, POS)
      ​Chest X-ray showed catheter compression and deformation in the costoclavicular space (with an angle of deflection >30°), accompanied by difficulty in blood aspiration or increased resistance to infusion.
   2. Puncture site infection
      ​The puncture site exhibited redness, swelling, heat, and pain, with purulent secretions; bacterial culture of the secretions was positive.
   3. Catheter-Related Thrombosis (CRT)
      ​Ultrasound/CT venography revealed thrombus formation within the catheter lumen or in the vein within 5 cm of the catheter tip, with or without clinical symptoms.
   4. Catheter occlusion:
      Complete occlusion: Inability to aspirate blood and significantly increased resistance to flushing with normal saline; (2) Partial occlusion: Difficulty in blood aspiration but ability to flush slowly with normal saline.

5. Assessment of complications, quality of life, satisfaction, and compliance

Complications included catheter occlusion, infection, thrombosis, bleeding, and mechanical dysfunction, which were assessed throughout the 48-week maintenance period. Patients' quality of life was evaluated at 48 weeks using the 36-item Short-Form Health Survey (SF-36)¹⁹, comprising 36 items across eight domains: general health, social function, physical role, bodily pain, physical function, vitality, mental health, and emotional role. Domain scores were standardized, weighted, and summed to yield a total score ranging from 0 to 100, with higher scores indicating better quality of life. At 48 weeks, patient satisfaction with venous access port management was assessed using a self-designed questionnaire containing 10 items, each rated on a 4-point Likert scale, resulting in a total score ranging from 0 to 40, where higher scores indicated greater satisfaction. Compliance with venous access port maintenance was evaluated at 24 and 48 weeks using another self-designed 10-item compliance questionnaire scored on a 4-point Likert scale, with total scores ranging from 0 to 32. Compliance levels were classified as follows: 28-32, indicating high compliance (strict adherence to requirements); 20-27, indicating moderate compliance; 12-19, indicating mild compliance; and 0-11, indicating poor compliance.

6. Statistical methods

The SPSS 27.0 statistical software was used to analyze the clinical values of the management schemes with different maintenance frequencies. Measurement data that conformed to the normal distribution were expressed as mean ± standard deviation, and the two independent samples t-test was adopted for comparison between groups. Count data were expressed as the number of cases (n) and percentage (%), and the χ² test was used for comparison between groups. Multivariate Logistic regression analysis was employed to analyze the influencing factors for the occurrence of complications in TIVAP. A p-value less than 0.05 was considered statistically significant for all analyses.

Clinical data of patients
There were no significant differences in baseline data and laboratory indicators among the three groups, as analyzed by one-way ANOVA and chi-square test (all P > 0.05), as shown in Table 1.

Thrombosis risk and catheter patency of TIVAP
There was no significant difference in thrombosis risk assessment among the three groups of patients (P > 0.05). All the patients' infusion ports had good catheter patency (97.97% vs. 97.03% vs. 97.14%), and there was no significant statistical difference in maintenance frequency (P> 0.05), see Table 2.

Occurrence of complications during the maintenance period
During the maintenance period, there were no significant differences in the incidence of key complication subtypes among the three groups: catheter-related thrombosis (Group A: 4.12%, Group B: 2.97%, Group C: 3.81%), catheter blockage (Group A: 4.12%, Group B: 4.95%, Group C: 3.81%), and puncture site infection (Group A: 2.06%, Group B: 3.96%, Group C: 2.86%); the overall complication rates were 16.49% (Group A), 16.83% (Group B), and 17.14% (Group C), with no statistical significance (χ2 = 0.273, P = 0.872), as shown in Table 3. To further clarify whether the incidence of complications was confounded by port indwelling time, the distribution of indwelling time and standardized complication incidence (per 1000 port-days) across the three groups were analyzed. As shown in Table 4, there was no significant difference in the median port indwelling time among Group A, Group B, and Group C (Kruskal-Wallis H test, H = 3.036, P = 0.219). Consistently, the standardized complication incidence per 1000 port-days was also comparable across groups: 0.37 (Group A), 0.38 (Group B), and 0.38 (Group C) (P > 0.05). These results confirmed that the similar complication rates among the three groups were not affected by differences in port indwelling time.

Comparison of maintenance costs and quality of life
The total cost related to 48-week maintenance in Group A was 168,005 yuan, that in Group B was 82,886 yuan, and that in Group C was 57,272 yuan, as shown in Figure 2A. There was a significant difference in the mean cost of maintenance among the three groups, as analyzed by one-way ANOVA (P < 0.05), as shown in Figure 2B. Compared with Group A, the maintenance costs in Group B decreased by 50.66%, and those in Group C decreased by 65.91%. Compared with Group B, the cost related to maintenance in Group C decreased by 30.90%. After 48 weeks of maintenance, there was no statistically significant difference in quality of life among the three patient groups, as analyzed by one-way ANOVA (P > 0.05), as shown in Figure 3.

Patient management satisfaction and follow-up compliance
The management satisfaction of patients in Group C was significantly lower than that in Group A at the intermediate stage, and the management satisfaction of patients in Group C was significantly lower than that in the other two groups at the late stage, as analyzed by two-way ANOVA (P < 0.05). The follow-up compliance of patients at the intermediate and late stages increased with the decrease in frequency, as analyzed by chi-square test for trend (P < 0.05), as shown in Table 5.

Multivariate analysis of complications related to the infusion port, univariate analysis
According to the occurrence of complications during the maintenance period, patients were divided into two groups: the complication group (n = 51) and the non-complication group (n = 252). The results of the univariate comparison revealed significant statistical differences in age, BMI, and the presence of combined chronic diseases between the two groups (P < 0.05), as shown in Table 6.

Multivariate analysis
Taking whether complications occurred during the patient's maintenance period as the dependent variable (no = 0, yes = 1), and taking age, BMI, and the presence of combined chronic diseases as independent variables and bringing them into the multivariate logistic regression model; among them, age is a continuous variable (the optimal threshold = 53.5 years old), the presence of combined chronic diseases is a binary variable, and BMI is a multi-category variable. The results of the logistic regression analysis revealed that older age, higher BMI, and the presence of combined chronic diseases were risk factors for patients to develop complications related to the infusion port (P < 0.05), as shown in Table 7.

DATA AVAILABILITY:
All data involved in this study have been provided in Supplementary File 1.

Figure 1: Research flow chart of implantable venous access port maintenance with different frequencies. The flow chart illustrates the enrollment of patients with malignant tumors, categorized by maintenance frequency (4-week, 8-week, or 12-week intervals), and a 48-week follow-up for complication monitoring. Please click here to view a larger version of this figure.

Figure 2: Comparison of mean maintenance costs for implantable venous access ports. (A) Total maintenance costs over 48 weeks for groups with 4-week (168,005 yuan), 8-week (82,886 yuan), and 12-week (57,272 yuan) intervals. (B) Mean costs show significant differences (one-way ANOVA, P < 0.001), with the 8-week and 12-week groups reducing costs by 50.66% and 65.91%, respectively, compared to the 4-week group. Please click here to view a larger version of this figure.

Figure 3: SF-36 quality of life scores among three maintenance frequency groups. SF-36 scores (0-100) for physical and mental health domains show no significant differences across groups (one-way ANOVA, F = 0.576, P = 0.563). Please click here to view a larger version of this figure.

Table 1: Baseline demographics and laboratory indices of study participants. Baseline characteristics (age, gender, BMI, tumor type) and laboratory values (platelets, white blood cells) are presented as mean ± SD or n (%). No significant differences were found among groups (independent samples t-test/chi-square test, all P > 0.05).

Table 2: Thrombosis risk and catheter patency assessment. Thrombosis risk evaluated by Wells score (mean ± SD) and catheter patency rate (n, %) shows no significant intergroup differences (one-way ANOVA/chi-square test, P > 0.05).

Table 3: Incidence of complications during maintenance period. Complication types (catheter blockage, infection, etc.) and total incidence (%) are shown. Chi-square test indicates no significant difference in complication rates among groups (P = 0.872).

Table 4: Comparison of port indwelling time and standardized complication incidence among three groups. Definitions: Port indwelling time = duration from port implantation to port removal/follow-up completion; Port-days = total number of days the port was indwelt across all patients in a group; Complication incidence per 1000 port-days = (number of complications / total port-days) × 1000. Statistical methods: Kruskal-Wallis H test was used for comparing median port indwelling time; Chi-square test was used for comparing the number of complications and complication incidence per 1000 port-days.

Table 5: Patient management satisfaction and follow-up compliance scores. Satisfaction and compliance scores (mean ± SD) were evaluated at 24 and 48 weeks using self-designed questionnaires. Follow-up compliance increased with decreasing maintenance frequency (one-way ANOVA, all P < 0.001).

Table 6: Univariate analysis of risk factors for port-related complications. Comparisons between complication (n = 51) and non-complication (n = 252) groups show significant differences in age, BMI, and comorbid chronic diseases (independent samples t-test/chi-square test, P < 0.05).

Table 7: Multivariate logistic regression analysis of port-related complication risks. Older age (OR = 1.048, 95% CI 1.018-1.079), high BMI (OR = 5.072 for BMI ≥ 30 kg/m²), and comorbid chronic diseases (OR = 3.391) were identified as independent risk factors (P < 0.05).

Supplementary File 1: Raw data generated during the study. Please click here to download this File.

The blood of patients with malignant tumors is in a hypercoagulable state, and they are more prone to catheter blockage than ordinary patients. Some patients are often accompanied by pleural effusion, ascites, bone metastasis, etc., resulting in forced postures. Long-term lateral or semi-recumbent positions can easily cause the catheter in the body to bend and kink, leading to catheter blockage²⁰. At the same time, the immunity decreases after chemotherapy, making it easier to catch a cold and experience severe coughs, which can cause blood to flow back into the catheter. If flushing is not performed in a timely manner, blood is prone to form thrombi in the catheter, thereby triggering a coagulation blockage. Since chemotherapy patients use the infusion port for a longer time and at a higher frequency, they are prone to infection. In addition, factors such as a lack of knowledge about catheter maintenance, inconvenient transportation, and economic conditions can cause patients to fail to maintain their catheters on time in the hospital, which can also lead to catheter blockage. Further exploration of the optimal frequency management of TIVAP and clarification of the risk factors related to infusion port infections are beneficial for clinical workers to conduct individualized risk stratification for different populations and formulate corresponding prevention plans.

The value of different infusion port maintenance frequencies
Zhang et al.²¹ reported in the study that 62.2% of patients who completed chemotherapy and were in the non-treatment period of TIVAP extended the flushing interval to 5-6 weeks without increasing the risk of complications. This indicates that during the non-treatment period of TIVAP, it is feasible to attempt to extend the flushing interval to more than 4 weeks for patients without a history of TIVAP-related complications within about one year. Wu et al.²² reported in a meta-analysis of prolonging the flushing interval of the TIVAP access port that prolonging the flushing interval to more than 4 weeks is safe and feasible, and prolonging it to 8 weeks may not increase the incidence of total complications and catheter blockage, but this study has not yet determined whether the flushing interval can be extended to 12 weeks or longer. Oh et al.²³ found in the study that among colorectal cancer patients who completed radical treatment, using and flushing the TIVAP at 3-month intervals is safe and feasible, with a TIVAP maintenance rate of 98.9%. 17% of the enrolled patients and 87% of the patients who relapsed and required intravenous chemotherapy could reuse the reserved port, avoiding the risk of reimplantation. Consistent with the above research results, this study found that, upon comparing different maintenance frequencies, there were no differences in quality of life, catheter patency, complication occurrence, or thrombosis risk among patients with maintenance frequencies of 4 weeks, 8 weeks, and 12 weeks. Even if the frequency of patients visiting the hospital for TIVAP maintenance is reduced, it will not increase the concurrent risk of adverse conditions, such as catheter thrombosis.

In the traditional maintenance process of TIVAP, the maintenance cycle is typically 4 weeks. The short maintenance interval makes it difficult for patients to return to their normal lives and also increases the economic burden on them. Compared with the standard 4-week maintenance protocol, the 8-week and 12-week extended protocols demonstrated significant cost advantages. Within a 48-week period, the total maintenance cost of Group B (8-week interval) was 50.66% lower than that of Group A (4-week interval) (CNY 82,886 vs. CNY 168,005), while the total maintenance cost of Group C (12-week interval) was 65.91% lower than that of Group A (CNY 57,272 vs. CNY 168,005). Generally, malignant tumor patients usually need to be examined for disease recurrence every 3-6 months²⁴. High-frequency infusion port maintenance admission not only increases financial, time, and energy costs but also increases the psychological burden on patients and reduces patient satisfaction. In this study, the follow-up compliance of patients increased with the decrease in frequency; performing TIVAP maintenance once every 12 weeks can not only ensure that the infusion port is buried under the patient's skin for a long time but also enable timely secondary treatment if malignant tumor recurrence occurs, without additional economic burden, relieve patient pain, and improve patient follow-up compliance.

The standard 4-week protocol requires patients to make 12 hospital visits annually, whereas the 8-week and 12-week protocols reduce this number to 6 and 4 visits, respectively. This substantially lowers patients' time costs and travel burden, and is of particular significance for patients with bone metastases, physical weakness, or those residing far from the hospital. The follow-up compliance score increased as the maintenance frequency decreased, indicating that the extended protocols are more aligned with patients' practical needs.

It is worth noting that the patients in the 8-week maintenance group had the highest satisfaction rate. This was mainly because this protocol achieved the optimal balance between reducing the medical burden and ensuring catheter safety. Compared with the 4-week group, the number of hospital visits and punctures was reduced by 50%, alleviating patients' pain and time costs, while avoiding the anxiety associated with excessively long intervals that may increase the risk of occlusion. This conclusion is similar to that drawn by Zhang et al.²⁵, who noted that an interval of approximately 6 weeks significantly improved satisfaction without increasing the risk of complications.

Risk factors related to infusion port complications
D'Souza et al.²⁶ reported in the study that the complication rate after TIVAP implantation in cancer patients was 14.0%, and most of the patients had concurrent infections, accounting for 12.2%, which is similar to the results of this study. Among the 303 patients in this study, 51 patients experienced complications, resulting in a complication rate of 16.83%. The results of the analysis of the influencing factors of infusion port-related complications in this study showed that older age, higher BMI, and the presence of combined chronic diseases were risk factors for patients to develop complications during the maintenance period.

In this study, for every one-year increase in the patient's age, the risk of developing infusion port-related complications increased by 4.3%. As age increases gradually, changes occur in the coagulation system, with an increase in the level of procoagulant factors and impairment of the fibrinolytic pathway, leading to an increased risk of thrombosis in elderly patients²⁷. Moreover, the memory of the elderly is somewhat impaired, and their ability to learn and understand new things is much worse than before. They are more passive in obtaining knowledge about infusion port maintenance, and fewer of them can actively use the Internet to search for relevant information about the arm infusion port. The channels are relatively single, and most elderly people only rely on the education of medical staff²⁸. In this study, patients with higher BMI had an increased risk of developing infusion port complications. The enlarged fat cells in overweight and obese patients can produce more bioactive substances and are often accompanied by hypertension, leading to thick blood, vascular endothelial dysfunction, and thus a procoagulant state. Wounds are more difficult to heal, resulting in pipeline blockage²⁹. At the same time, a higher body mass index can interfere with lipid and glucose metabolism, thereby enhancing the activity of the coagulation system and reducing fibrinolytic activity, which leads to an increased incidence of thrombosis³⁰. However, some studies have shown that patients with overly thin bodies are prone to displacement of the infusion port base due to a lack of sufficient muscle and fat support, which can also lead to slow local blood flow. In addition, skin friction damage can also easily lead to infection³¹, but this conclusion was not supported in this study. Therefore, it is recommended to assess the patient's body mass index and incorporate body mass index management into the management of cancer patients. In this study, the concurrent risk of patients with combined chronic diseases was 239.1% higher compared to other patients. Patients with combined hypertension have arteriosclerosis, increased blood viscosity, and gradually increased vascular resistance, providing favorable conditions for the formation of thrombosis³². In patients with combined diabetes, the body is in a hyperglycemic environment, which is conducive to the growth and reproduction of bacteria. The increased plasma osmotic pressure inhibits the phagocytic ability of white blood cells, reducing the body's resistance to infection. The disordered protein metabolism in diabetic patients leads to an imbalance in humoral immune function, increasing the risk of infection³³.

Maintenance recommendations for implantable venous access ports
To reduce the risk of common issues such as catheter blockage, abnormal puncture sites, and thrombosis during infusion port maintenance, targeted maintenance recommendations have been developed based on clinical practice:

For non-thrombotic blockage: (1) First, perform negative-pressure flushing. Use 10mL saline, aspirate 0.5mL to create negative pressure, then flush¹⁶. If this is ineffective, use urokinase pulsation. Inject 0.5mL of 10,000 U/mL urokinase, clamp the catheter for 15 min, and then flush. (2) For a puncture site oozing or infection: Prevent oozing by applying butterfly tape with gauze. Use mild pressure (less than 20mmHg) and limit limb movement. Manage infection through iodophor disinfection (covering an area no smaller than 10cm), application of alginate dressings, and local antibiotics selected based on culture results. (3) For patients at higher thrombosis risk: Administer prophylactic low-molecular-weight heparin at a dose of 4000IU subcutaneously once daily after chemotherapy. Conduct ultrasound checks every 2 weeks, and shorten the maintenance interval to 4 weeks if a mural thrombus smaller than 3mm is detected.

Preventive measures for complications of the infusion port
This study suggests that extending the infusion port management time is feasible and safe, without increasing the risk of complications. However, while reducing the maintenance frequency, more stringent management of patients during the non-chemotherapy period is necessary to ensure that patients have a good understanding of the knowledge related to infusion port maintenance and can improve their self-management level. In addition, D'Souza²⁶ also compared the complication rates in different time periods of the hospital. The rates decreased significantly over time, indicating that there is a learning curve for medical staff in healthcare institutions regarding TIVAP. Therefore, there is a significant relationship between the occurrence of patients' complications and the management of the infusion port by medical staff. Thus, managers should focus on strengthening the training of relevant knowledge for medical staff. Before, during, and after the placement of the infusion port, the catheterization site and surrounding tissues should be evaluated, and health education on preventing complications should be provided. For elderly patients, it is recommended that young family members be accompanied as much as possible when explaining the knowledge of infusion port maintenance. During follow-up, precautions should also be repeatedly explained, and guidance should be given patiently. For patients with a high body mass index or those with combined chronic diseases, guide them to perform slow aerobic exercises. At the same time, avoid large arm movements that may pull the catheter, thereby reducing the risk of catheter displacement. According to the patient's condition, instruct the patient to maintain a balanced diet, avoid high-fat foods, keep their body weight within a normal range, and consume high-fiber foods in moderation. Some patients may experience changes in body shape during the treatment process, such as obesity or emaciation. These changes in body shape may cause the catheter to shift or deform in the body.

This study still has limitations, including a small sample size and a relatively short research period. In the future, multicenter studies with extended follow-up periods can be conducted to enhance the universality and representativeness of the research results. In addition, there is currently no unified standard for the concentration of the infusion port sealing fluid. In this study, heparin at a concentration (100 U/mL) consistent with the recommended standard of the international normalized ratio was used for catheter sealing, which is consistent with the heparin concentration for catheter sealing in other recent studies³⁴. In the future, further research can be conducted on the effects of sealing fluid concentration and flushing volume on maintenance frequency.

Conclusion
In conclusion, through professional catheter maintenance and effective education and guidance provided by nursing staff, cancer patients can appropriately reduce the frequency of catheter maintenance after chemotherapy. This can ensure the safety of patients using the totally implantable venous access port (TIVAP), improve patients' compliance with catheter maintenance, alleviate the burden on patients, and contribute to the widespread adoption and application of TIVAP among cancer patients.