Mid-term Results of a Novel Dedicated Venous Stent for the Treatment of Chronic Thoracic Central Vein Obstruction of Benign Aetiology

Early experience with the Abre venous stent for central venous stenoses and occlusions in hemodialysis patients

BACKGROUND

Hemodialysis patients are prone to stenoses and occlusions throughout the access circuit. Central venous stenoses or occlusions (CVO) can be particularly challenging. There are many different types of balloons and stents available for treatment, including a new generation of dedicated venous stents (VS). In this study, we report our experience and patency rates with the Abre VS in central venous lesions in hemodialysis patients.

METHODS

From April 2020 to May 2023, all procedures with Abre VSs placed for central venous lesions in hemodialysis patients were retrospectively analyzed from a prospectively collected database of 980 hemodialysis access interventions. Follow up outcomes were obtained from angiographic images on follow up angiography and included primary patency and primary assisted patency. Effective hemodialysis was considered a surrogate for access patency if no angiographic follow-up was available.

RESULTS

A total of 15 patients with CVO were treated with the Abre VS. Technical success was 100%. All patients were able to achieve adequate hemodialysis after VS placement. Stents were placed across the thoracic inlet in 73% of patients. Post procedure primary patency at the target lesion site was 85% at 6 months and 70% at 12 months. Primary assisted patency of the circuit was 93% at 6 and 12 months. No stent fractures were observed.

CONCLUSION

Treatment of CVO remains extremely challenging, especially when the lesion is located at the thoracic inlet. In these patients, VSs provide acceptable primary patency rates and allow patients to continue to receive effective hemodialysis. However, routine follow-up and re-interventions will likely be necessary to maintain patency in the long term.

A Systematic Review and Meta-analysis of 24 Month Patency After Endovenous Stenting of Superior Vena Cava, Subclavian, and Brachiocephalic Vein Stenosis

OBJECTIVE

This systematic review and meta-analysis aimed to appraise recent evidence assessing patency outcomes at various time points in patients with superior vena cava, subclavian, and brachiocephalic vein stenosis who had undergone stenting.

DATA SOURCES

PubMed, Scopus, and Cochrane Library databases were searched for studies up to December 2022.

REVIEW METHODS

Measured outcomes included technical success rate, primary, primary assisted, and secondary patency at various time points. A subgroup analysis was also conducted to compare malignant and benign obstruction. GRADE was used to assess the certainty of evidence.

RESULTS

Thirty nine studies reporting outcomes in 1 539 patients were included in the meta-analysis. Primary patency up to one year after the procedure was 81.5% (95% CI 74.5 - 86.9%). Primary patency declined after one year to 63.2% (95% CI 51.9 - 73.1%) at 12 - 24 months. Primary assisted patency and secondary patency at ≥ 24 months were 72.7% (95% CI 49.1 - 88.0%) and 76.6% (95% CI 51.1 - 91.1%). In the subgroup analysis, primary patency was significantly higher in patients with a malignant stenosis compared with a benign stenosis at 1 - 3 and 12 - 24 months. No significant difference was seen for pooled secondary patency rates when comparing the malignant and benign subgroups. GRADE analysis determined the certainty of evidence for all outcomes to be very low.

CONCLUSION

Stenting is an effective intervention for benign and malignant stenosis of the superior vena cava, subclavian, and brachiocephalic veins. Primary patency rates were good up to one year after the procedure, with 81.5% of stents retaining patency at 6 - 12 months. Patency rates declined after one year, to 63.2% primary and 89.3% secondary patency at 12 - 24 months, showing improved outcomes following re-intervention. High quality evidence is lacking. More research is needed to investigate patency outcomes and the need for surveillance or re-intervention programs.

Risk factors for in-stent restenosis in maintenance hemodialysis patients with central venous occlusive disease and biomechanical assessment of stents

OBJECTIVES

To investigate the risk factors and biomechanical mechanisms of in-stent restenosis (ISR) in central venous occlusive disease (CVOD).

PATIENTS AND METHODS

This retrospective study consecutively included 77 maintenance hemodialysis (MHD) patients with CVOD who received the first percutaneous transluminal angioplasty with stenting (PTS) due to symptomatic CVOD in a tertiary hospital. The mean age was 59.7 ± 14.0 years, and 51.9% of patients were male. The clinical characteristics, occurrence of ISR and patency rates were recorded. Finite element method was applied to assess the biomechanical properties of stents.

RESULTS

Among 77 patients with a mean CVS score of 8.0 ± 2.8, 20.8%, 62.3%, and 16.9% of patients had the main vein of CVOD in the subclavian vein, brachiocephalic vein, and superior vena cava, respectively. A total of 72 (93.5%) patients received successful PTS treatment, for which the stents implanted were mainly Fluency covered stent (48.6%) and SMART bare stent (31.9%). During 15 (10-24)-months of follow-up, ISR occurred in 36.1% of the 72 patients. The primary and assisted primary patency rates at 6, 12, and 18 months were 78%, 56%, 42% and 95%, 90%, 87%, respectively. A prolonged dialysis vintage was an independent risk factor for ISR, yet the stent type or the main vein location was not correlated with ISR. Among three laser-engraving stents, the SMART stent was the best in terms of flexibility, stress, and strain on stents but worst in stress or strain on vessels. The Luminexx stent was the best in radial force and worst in stress or strain on stents. The Vici stent was the best in stress and strain on vessels and worst in radial force and flexibility.

CONCLUSIONS

An unsatisfactory comprehensive biomechanical performance from configurations rooted in existing stents may account for the high incidence of ISR in CVOD.

Objective Performance Goals Based on a Systematic Review and Meta-Analysis of Clinical Outcomes for Bare-Metal Stents and Percutaneous Transluminal Angioplasty for Hemodialysis-Related Central Venous Obstruction

PURPOSE

To use safety and efficacy outcomes following treatment with percutaneous transluminal angioplasty (PTA) and/or stent placement for thoracic central venous obstruction in hemodialysis-dependent patients to establish objective performance goals (OPGs).

METHODS

A systematic literature review and meta-analysis were conducted for articles published between January 1, 2000, and August 31, 2021. Efficacy outcomes included primary patency rates at 6 and 12 months, and safety outcomes included adverse events (AEs) categorized as access loss, procedure-related AEs, and serious AEs (SAEs). OPGs were derived from the upper and lower bounds of the 95% confidence intervals for primary patency and SAE rates.

RESULTS

Of 66 articles reviewed, 17 met the inclusion criteria (PTA, n = 4; stent placement, n = 5; PTA/stent, n = 8). The 6- and 12-month primary patency rates for PTA were 50.9% and 36.7%, respectively. Based on these findings, the proposed 6- and 12-month primary patency OPGs identifying superiority against PTA were 66.5% and 52.6%, respectively, and those for noninferiority were 39.0% and 25.7%, respectively. For stent placement, the 6- and 12-month primary patency rates were 69.7% and 47.9%, respectively. The proposed 6- and 12-month primary patency OPGs identifying superiority were 82.1% and 64.1%, respectively, and those for noninferiority were 59.3% and 35.8%, respectively. SAE rates for PTA and stent placement were 3.8% and 8.1%, respectively. Proposed safety OPGs for noninferiority versus superiority for PTA and stent placement were 10.1% versus 1.4% and 13.6% versus 4.8%, respectively.

CONCLUSION

The OPGs derived from real-world studies of PTA and stent placement may serve as a benchmark for future interventions indicated for this patient population.

Venous stent versus conventional stent for the treatment of central vein obstruction in hemodialysis patients: a retrospective study

BACKGROUND

Endovascular treatment is a first-line treatment for upper thoracic central vein obstruction (CVO). Few studies using bare venous stents (BVS) in CVO have been conducted.

PURPOSE

To evaluate the treatment performance of upper thoracic central vein stenosis between BVS and conventional bare stent (CBS) in hemodialysis patients.

METHODS

Hemodialysis patients with upper thoracic central vein obstruction who underwent endovascular treatment at the interventional unit of our institution from 1 January 2008 to 31 December 2018 were enrolled in the present study. CBS was used to treat central vein obstruction in 43 patients and BVS in 34 patients. We compared the primary patency rates and complications between the two stent types. P values < 0.05 were considered statistically significant.

RESULTS

The patient demographic data between the CBS and BVS groups were similar. The characteristics of the lesions, procedures, and complications were not significantly different between the two groups (P > 0.05). There were no statistically significant differences of primary patency rates at three and six months between the BVS and CBS groups (94.1% vs. 86.0% and 73.5% vs. 58.1%, respectively; P > 0.05). The primary patency rate at 12 months in the BVS group was significantly higher than that in the CBS group (61.8% vs. 32.6%; P = 0.008).

CONCLUSION

Endovascular treatment of central vein obstruction with BVS provided a higher primary patency rate at 12 months than CBS.

Outcome of stenting in central venous obstruction of benign etiology

Background: The aim of this study is to evaluate long term outcome in patients treated for benign superior vena cava (SVC) syndrome by endovascular techniques. Patients and methods: Between 2015 and 2018, 62 patients suffering from central venous obstruction of benign etiology underwent balloon angioplasty with stent placement for venous obstruction in our department. Patency was assessed clinically, using duplex ultrasound in all patients or with CT-phlebography in selected cases. Results: Median age was 60 years (23-83), forty-one patients (66%) had central venous devices. Swelling of the arm and face were the main symptoms (71%). During the median follow up of 22 months (9-38), cumulative primary patency was 71% after venous stenting. The cumulative assisted primary and the secondary patency were 85% and 92%, respectively. Conclusions: Recanalization and stenting of central vein obstruction has turned out to be the technique of reference and provides satisfactory mid-term patency rates. After adjusting for the risk factors, presence of AV-fistula remained a significant risk factor for recurrent stenosis or loss of patency after intervention.