Numerical modelling of the interaction between dialysis catheter, vascular vessel and blood considering elastic structural deformation

The dialysis catheter indwelling in human bodies has a high risk of inducing thrombus and stenosis. Biomechanical research showed that such physiological complications are triggered by the wall shear stress of the vascular vessel. This study aimed to assess the impact of CVC implantation on central venous haemodynamics and the potential alterations in the haemodynamic environment related to thrombus development. The SVC structure was built from the images from computed tomography. The blood flow was calculated using the Carreau model, and the fluid domain was determined by CFD. The vascular wall and the CVC were computed using FEA. The elastic interaction between the vessel wall and the flow field was considered using FSI simulation. With consideration of the effect of coupling, it was shown that the catheter vibrated in the vascular systems due to the periodic variation of blood pressure, with an amplitude of up to 10% of the vessel width. Spiral flow was observed along the catheter after CVC indwelling, and recirculation flow appeared near the catheter tip. High OSI and WSS regions occurred at the catheter tip and the vascular junction. The arterial lumen tip had a larger effect on the WSS and OSI values on the vascular wall. Considering FSI simulation, the movement of the catheter inside the blood flow was simulated in the deformable vessel. After CVC indwelling, spiral flow and recirculation flow were observed near the regions with high WSS and OSI values.

Outcomes of stent grafts for treatment of central venous disease in hemodialysis patients

BACKGROUND

To evaluate the effectiveness of stent graft (SG) for the treatment of central venous disease (CVD) in hemodialysis patients.

METHODS

Between January 2014 and April 2022, 122 patients on hemodialysis with symptomatic CVD were treated with percutaneous transluminal angioplasty (PTA) and bare-metal stent (BMS) or SG placement. The mean follow-up was 14.5 months (IQR: 8.0, 24.2). Patency rates of the target sites were calculated using Kaplan-Meier and log-rank studies. Multivariate Cox proportional hazard models were used to evaluate the association between various characteristics and target site primary patency.

RESULTS

Technical success rate was 100%. At 3, 6, 12, and 24 months, the target sites primary patency rates were 86.4%, 74.2%, 45.1%, and 30.4% for PTA; 94.7%, 78.6%, 60.8%, and 45.6% for BMS; and 94.0%, 92.0%, 82.4%, and 66.8% for SG, respectively, and the assisted primary patency rates were 86.5%, 80.4%, 63.8%, and 46.0% for PTA; 94.7%, 89.5%, 77.5%, and 71.1% for BMS; 100%, 100%, 97.8%, and 83.4% for SG, respectively. The Kaplan-Meier analysis indicated that SGs achieved better primary and assisted primary patency than PTA or BMS (p<0.05). SG use and concomitant stenosis were the independent predictors of target site primary patency dysfunction in the multivariate analysis.

CONCLUSIONS

This study confirmed the better long-term patency of SG in comparison with PTA and BMS for the treatment of CVD in hemodialysis patients.

Evaluation of a new paclitaxel-coated balloon catheter in an in vivo porcine peripheral venous model: Feasibility, safety, and drug deliverability

PURPOSE

To evaluate in vivo the feasibility, safety, and paclitaxel (PTX) deliverability of a newly developed non-commercially available Paclitaxel-Coated Balloon (PCB) catheter in the swine healthy peripheral vein model.

MATERIALS AND METHODS

In total 12 PCBs were deployed in 12 venous segments. Primary feasibility endpoint was the successful application of the devices to the veins of the animals. Primary efficacy endpoint was the determination of the drug content in the venous tissue at 24 h and 7 days after balloon expansion, as assessed by analysis of the vein tissue with High Performance Liquid Chromatography (HPLC) coupled with tandem mass spectrometry. Primary safety endpoint was freedom from any major adverse event. Secondary endpoint was the investigation of any independent factor affecting the primary endpoints.

RESULTS

Paclitaxel was detected in five out of six tissue samples 24 h post-intervention and five out of six tissues at 7 days following the procedure (10 tissue samples out of 12). The mean weight of tissue that was examined was 0.20604 ± 0.29822 g (range: 1.02823-0.03377 g) and the mean PTX concentration detected was 8.4 ± 13.1 μg/g (range: 0-36.1 μg/g). The average drug content detected at 24 h (17.1 ± 17.1 μg/g) was numerically superior, but non-statistically significant, compared to 7 days (3.1 ± 3.6 μg/g). An average of 33.8% of the drug remained on the balloon after retrieval. According to the multiple linear regression analysis, there was no significant correlation between transition time, PTX remaining on the balloon, time of analysis (24 h/7 days) and PTX tissue concentration. No abnormalities were noted during autopsy.

CONCLUSION

The newly developed PCB successfully delivered within the healthy venous wall a dose of Paclitaxel that inhibits neointimal hyperplasia. No safety issues were raised at short-term follow-up.

Clinical outcome of percutaneous angioplasty and covered stent placement for treatment of left brachiocephalic vein obstruction in hemodialysis patients

BACKGROUND

Left brachiocephalic vein (LBV) obstruction is a common complication in patients undergoing hemodialysis. This study aimed to compare the clinical characteristics and outcomes of patients with LBV obstruction who underwent percutaneous angioplasty or stenting.

METHODS

We performed a retrospective study of 67 hemodialysis patients with LBV stenosis or occlusion who underwent percutaneous transluminal angioplasty (PTA; n = 25) or percutaneous transluminal stenting (PTS; n = 42). We compared the clinical characteristics, lesion features, and patency between the two groups of patients.

RESULTS

The average age, sex, smoking history, body mass index, obstruction period, comorbidities, and clinical manifestations were comparable between the PTA and PTS groups. Prior ipsilateral catheterization was less common in the PTS group than in the PTA group (14.3% vs 36.0%, p < 0.05). Smaller sized balloons were used in the PTS group than in the PTA group (p < 0.05). The overall primary patency rates were similar between the two groups, whereas the secondary patency rate in the PTS group was higher than that in the PTA group (p < 0.05). The average age, sex, smoking history, body mass index, obstruction period, prior ipsilateral catheterization, comorbidities, and types of lesions were comparable between patients with or without restenosis, while patients with restenosis had a higher percentage of high venous pressure than those without restenosis (87.5% vs 60.5%, p < 0.05).

CONCLUSION

The primary patency rates were similar in the angioplasty and the stenting groups. Stenting has a significantly higher secondary patency rate than angioplasty alone for treating LBV obstruction and is required more commonly in patients without prior ipsilateral catheterization.

ACR Appropriateness Criteria® Dialysis Fistula Malfunction

The creation and maintenance of a dialysis access is vital for the reduction of morbidity, mortality, and cost of treatment for end stage renal disease patients. One's longevity on dialysis is directly dependent upon the quality of dialysis. This quality hinges on the integrity and reliability of the access to the patient's vascular system. All methods of dialysis access will eventually result in dialysis dysfunction and failure. Arteriovenous access dysfunction includes 3 distinct classes of events, namely thrombotic flow-related complications or dysfunction, nonthrombotic flow-related complications or dysfunction, and infectious complications. The restoration of any form of arteriovenous access dysfunction may be supported by diagnostic imaging, clinical consultation, percutaneous interventional procedures, surgical management, or a combination of these methods. This document provides a rigorous evaluation of how variants of each form of dysfunction may be appraised and approached systematically. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

A surgical method to be reminded for the treatment of symptomatic ipsilateral central venous occlusions in patients with hemodialysis access: Axillo-axillary venous bypass case report and review of the literature

BACKGROUND

In this case report, we present two chronic hemodialysis patients with upper extremity swelling due to central venous occlusions together with their clinical presentation, surgical management and brief review of the literature.

METHODS

The first patient who was a 63-year-old female patient with a history of multiple bilateral arteriovenous fistulas (AVFs) was referred to our clinic. Physical examination demonstrated a functioning right brachio-cephalic AVF, with severe edema of the right arm, dilated venous collaterals, facial edema, and unilateral breast enlargement. In her history, multiple ipsilateral subclavian venous catheterizations were present for sustaining temporary hemodialysis access. The second patient was a 47-year-old male with a history of failed renal transplant, CABG surgery, multiple AV fistula procedures from both extremities, leg amputation caused by peripheral arterial disease, and decreased myocardial functions. He was receiving 3/7 hemodialysis and admitted to our clinic with right arm edema, accompanied by pain, stiffness, and skin hyperpigmentation symptoms ipsilateral to a functioning brachio-basilic AVF. He was not able to flex his arms, elbow, or wrist due to severe edema.

RESULTS

Venography revealed right subclavian vein stenosis with patent contralateral central veins in the first patient. She underwent percutaneous transluminal angioplasty (PTA) twice with subsequent re-occlusions. After failed attempts of PTA, the patient was scheduled for axillo-axillary venous bypass in order to preserve the AV access function. In second patient, venography revealed right subclavian vein occlusion caused secondary to the subclavian venous catheters. Previous attempts for percutaneously crossing the chronic subclavian lesion failed multiple times by different centers. Hence, the patient was scheduled for axillo-axillary venous bypass surgery.

CONCLUSION

In case of chronic venous occlusions, endovascular procedures may be ineffective. Since preserving the vascular access function is crucial in this particular patient population, venous bypass procedures should be kept in mind as an alternative for central venous reconstruction, before deciding on ligation and relocation of the AVF.

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.

Prospective, Multicenter, Observational Study to Evaluate a Cell-Impermeable Endoprosthesis for Treatment of Stenosis or Occlusion within the Dialysis Outflow Circuit of an Arteriovenous (AV) Fistula or AV Graft (The WRAP Registry)

PURPOSE

Dysfunctional vascular access due to stenosis/occlusion within the arteriovenous fistula or graft (AVF/AVG) negatively affects the clinical management of patients undergoing hemodialysis. Results from the feasibility study of the WRAPSODY™ Cell-Impermeable Endoprosthesis demonstrated that the device can achieve high patency rates and maintain integrity of the dialysis outflow circuit. This study was designed to assess real-world evidence of safety and efficacy outcomes following device placement.

MATERIALS AND METHODS

This is a prospective, multicenter, non-investigational, post-market observational study of 500 patients at up to 50 centers worldwide with a mature AVF/AVG dialysis access (≥ 1 hemodialysis session) who experience stenosis/occlusion of the outflow circuit prior to placement of WRAPSODY. Patients will be divided into the following two cohorts: peripheral or central thoracic. Primary outcome measures include target lesion primary patency (TLPP) at 6 months and procedure and/or device-related events through 30 days post-procedure. Secondary outcome measures include TLPP, safety events, and the number of interventions needed to maintain patency through the 24 month study period. Exploratory endpoints include time to access abandonment, resumption of successful dialysis, functional patency, and pending available imaging data, any incidence of stent fractures, migration, or edge stenosis. Study enrollment began in June 2022, the last patient visit is expected in 2026.

DISCUSSION

It is expected that this study will provide real-world evidence regarding the performance of the WRAPSODY device in a diverse population of patients, which may encourage its use in the continuum of hemodialysis access management.

TRIAL REGISTRATION

NCT05062291.

Clinical characteristics of hemodialysis patients with left brachiocephalic vein obstruction due to extrinsic compression or prior catheterization

BACKGROUND

Left brachiocephalic vein (LBCV) stenosis is a common complication in hemodialysis patients and is a heterogenous disorder associated with either prior catheterization or extrinsic compression. This study aimed to characterize patients with LBCV stenosis or occlusion with and without a history of central venous catheterization.

METHODS

We performed a retrospective study in 84 hemodialysis patients with LBCV stenosis or occlusion with (n = 22) or without (n = 62) prior catheterization. We compared the clinical features, anatomical factors, restenosis after balloon venoplasty, and patency rates of patients in these two groups.

RESULTS

In the cohort of 84 patients with LBCV stenosis or occlusion, 73.8% (62 patients) of them had no history of catheterization. Patients without prior catheterization had more stenotic lesions (p < 0.05) but less occlusive lesions (p < 0.05) than patients with prior catheterization. The space between the sternum and the aorta was narrower in patients without prior catheterization than that in patients with prior catheterization (p < 0.05). Percutaneous venography was performed in 81 patients, and the occurrence of recoil after venoplasty in patients without prior catheterization was significantly higher than that in patients with prior catheterization (p < 0.05). The rate of stent implantation was significantly higher in patients without prior catheterization than patients with prior catheterization (p < 0.05), whereas there was no significant difference in primary patency between the two groups.

CONCLUSIONS

LBCV stenosis and occlusion are mainly due to extrinsic compression rather than prior central venous catheterization. Stent implantation is frequently required after venoplasty to treat LBCV obstructive lesions in patients without prior catheterization.

Acute venous problems: Integrating medical, surgical, and interventional treatments

"Acute venous problems" refers to a group of disorders that affect the veins and result in sudden and severe symptoms. They can be classified based on the pathological triggering mechanisms, such as thrombosis and/or mechanical compression, and their consequences, including symptoms, signs, and complications. The management and therapeutic approach depend on the severity of the disease, the location, and the involvement of the vein segment. Although summarizing these conditions can be challenging, the objective of this narrative review was to provide an overview of the most common acute venous problems. This will include an exhaustive yet concise and practical description of each condition. The multidisciplinary approach remains one of the major advantages in dealing with these conditions, maximizing the results and the prevention of complications.

Long-Term Outcome of a "Mother-Child" Coaxial Dual-Catheter Technique for Percutaneous Transluminal Angioplasty of Central Vein Stenosis or Occlusion in Hemodialysis Patients

PURPOSE

This study aims to evaluate the long-term outcome and prognostic factors of a "mother-child" coaxial dual-catheter technique for percutaneous transluminal angioplasty (PTA) in the treatment of central vein stenosis (CVS) or central vein occlusion (CVO).

MATERIALS AND METHODS

During September 2017 to August 2020, totally, 76 hemodialysis patients with symptomatic CVS or CVO were treated with PTA using the mother-child technique. The success rate, complications, and follow-up information were collected. Cox proportional hazard analysis was used to explore the predicting factors of primary patency. Primary patency rates of different subgroups were generated with the Kaplan-Meier analysis and compared using the log-rank (Mantel-Cox) test.

RESULTS

There were 31 CVS patients and 45 CVO patients who presented with 114 PTAs. The initial procedure success rate was 98.25%. By the end of the follow-up, 57 patients (75%) had maintained functioning fistula after initial or repeated PTAs. The primary patency rates were 88.75% at 3 months, 73.36% at 6 months, 55.83% at 12 months, and 50.75% at 18 months. The secondary patency rates were 97.14% at 6 months, 87.66% at 12 months, and 82.18% at 24 months. The predictors for primary patency were history diabetes mellitus (hazard ratio [HR] = 3.1, 95% confidence interval [CI]: 1.31-7.30, P = .010), abnormal white blood cell count (HR = 1.44, 95% CI: 1.18-1.75, P < .001), lesion at subclavian-innominate vein (HR=2.75, 95% CI: 1.34-5.63, P = .006), and occlusion (HR=0.33, 95% CI: 0.14-0.76, P = .010). The primary patency was significantly lower in the subclavian-innominate vein subgroup, with a median primary patency of 4.5 (3-12.75) months, than in the nonsubclavian-innominate vein subgroup (8.5 [5-13] months; P = .005). The median duration of each PTA was 8 months for the first PTA, 7.5 months for the second PTA, and 5 months for the third PTA. There was no significant difference in the patency duration of repeated PTAs and the primary PTA (P = .389).

CONCLUSIONS

The mother-child coaxial dual-catheter technique has a good success rate and acceptable primary patency in the treatment of hemodialysis patients with CVS or CVO. Repeated PTA is as effective as the primary PTA.

CLINICAL IMPACT

This is the follow up report on the "Mother-Child" coaxial dual-catheter technique for percutaneous transluminal angioplasty of central vein stenosis or occlusion in hemodialysis patients since we first presented it in 2019. In this paper, we can see that the long-term patency rate of this technique for central venous disease is satisfactory, and repeated use of this technique does not affect the patency time. Compared with other literature reports, the surgical success rate of this technique is significantly improved. Therefore, this technique is worth popularizing in the treatment of central venous disease.

Clinical outcomes of endovascular therapy with vascular stents for central venous obstruction in hemodialysis patients

BACKGROUND

Symptomatic central venous obstruction (CVO) is sometimes observed in patients undergoing hemodialysis. Angioplasty is generally performed for salvage purposes, and stent implantation is performed as a last resort to prevent permanent venous occlusion. However, published reports about the clinical outcomes of stenting for CVO have been limited by the small number of included patients and the relatively old generation of analyzed stents. This study aimed to clarify the safety and efficacy of endovascular therapy (EVT) using stents for symptomatic CVO in contemporary practice.

METHODS

This retrospective review was performed between May 2012 and August 2021. We retrospectively analyzed consecutive 31 lesions (31 patients, 64 ± 10.7 years old) treated with a vascular stent for elastic recoil after balloon angioplasty or recurrent stenosis <3 months after angioplasty. The primary outcome was primary patency, defined as freedom from target lesion revascularization. The secondary outcome was assisted primary patency, defined as freedom from permanent occlusion of the target stents.

RESULTS

In all cases, stents were successfully deployed on the target lesions. No EVT-related complications were observed. Self-expandable and balloon-expandable stents were used in 26 and 5 lesions, respectively. The median follow-up period was 18 months (interquartile range, 7-40). Kaplan-Meier analysis revealed that the primary patency rates were 66.1 % at 6 months, 61.7 % at 12 months, and 38.4 % at 24 months after EVT. The assisted primary patency rate was 70.3 % 24 months after EVT. In the multivariate analysis, younger age was the only independent predictor of target lesion revascularization (hazard ratio: 0.92, 95 % CI: 0.85-0.99, p = 0.04).

CONCLUSIONS

Stent implantation for CVO that is resistant to standard angioplasty seems safe and effective.

Clinical Implications of Phenotypes of Hemodialysis Patients With Central Venous Occlusion or Central Venous Stenosis Defined by Cluster Analysis

Objective

This study aims to investigate the association between clinical factors of patients with central (superior vena cava, brachiocephalic, or subclavian) venous occlusion or central venous stenosis (CVO/CVS) and the difficulty of interventional recanalization as well as the duration of postoperative patency.

Methods

A total of 103 hemodialysis patients with CVO/CVS treated with endovascular treatment were enrolled. The two-step cluster analysis was selected to differentiate the cases into distinct phenotypes automatically. Differences in characteristics, the difficulty of interventional recanalization, and the duration of postoperative primary patency time between the two clusters were statistically compared.

Results

The 103 cases were divided into distinct two clusters by the two-step cluster analysis with 48 (46.6%) in cluster 1 and 55 (53.4%) in cluster 2. Compared to cluster 2, patients in cluster 1 have a higher proportion of blunt stump, side branches, occlusion lesions >2 cm, calcification, or organization. Moreover, the above four factors were, in turn, the most critical four predictors distinguishing 103 patients into two clusters. The remaining six factors were, in turn, occlusion located in the superior vena cava (SVC), duration of central venous catheterization (CVC), lesion location, vessel diameter, number of CVC, and previously failed lesion. Of the four most important factors, with the exception of occlusion lesions exceeding 2 cm, there were significant differences in the length of procedure time between the groups grouped by the remaining three factors. And there was a significant difference in the primary patency rate between the group with blunt stump and the group without blunt stump and also between the group with occlusion lesions ≥ 2 cm and the group with occlusion lesions <2 cm. The operation time of cluster 1 was longer than that of cluster 2. In terms of postoperative patency time, the primary patency time was significantly longer in the patients of cluster 2 compared with cluster 1 (P = 0.025).

Conclusion

Patients were divided into distinct two clusters. CVO/CVS of patients in cluster 1 was more challenging to be recanalized than that in cluster 2, and the primary patency time was significantly longer in the patients of cluster 2 compared with cluster 1. Blunt stump, side branches, occlusion lesions exceeding 2 cm, and calcification or organization are the four most critical predictors distinguishing 103 patients into two clusters.

Comparison of Management for Central Venous Stenosis With or Without Previous Catheter Placement

Objective: To compare central venous stenosis/occlusion with or without previous jugular catheter placement history.

Methods: Data of patients with central vein stenosis/occlusion receiving endovascular intervention in our hospital from January 2015 to December 2018 were collected and analyzed.

Results: Twenty-nine patients with previous jugular catheter placement history (CVC group) and 33 patients (excluded two with technical failure) without such history (non-CVC group) are included in this study. Previous jugular catheter placement history raised the risk of postintervention recurrence 1.02 times (CVC group vs. non-CVC group, HR = 2.02 95%CI: 0.91–4.48). The primary patency rate at 6, 12, 18, and 24 months was 76.9, 54.2, 45.5, and 25.0% separately in the CVC group and 80.6, 70.0, 67.9, and 44.4% separately in the non-CVC group. The assisted primary patency rate at 6, 12, 18, and 24 months was 92.3, 91.7, 86.4, and 68.8% separately in the CVC group and 93.5, 90.0, 82.1, and 61.1% separately in the non-CVC group. Patients in the CVC group received a higher frequency of reintervention (0.7 times/year/patient vs. 0.3 times/year/patient). There was no significant difference in the assisted primary patency rate between the two groups. Different primary interventions (angioplasty alone, bare metal stent, stent graft) did not affect primary patency and assisted primary patency, but percutaneous transluminal stenting (PTS) with a bare metal stent had a significant lower primary patency rate between 3 and 24 months compared with PTS with a stent graft (p = 0.011).

Conclusion: Central venous stenosis/occlusion with a previous jugular catheter placement history develops symptoms earlier and had a worse prognosis after endovascular intervention. More efforts are needed to carry out end-stage kidney disease life plan to reduce the harm of evitable catheter placement.

Arteriovenous fistulas for hemodialysis: Brief review and current problems

The number of people worldwide living with end-stage renal disease is increasing. Arteriovenous fistulas are the preferred method of vascular access in patients who will require hemodialysis. As the number of patients with arteriovenous fistulas grows, the role of physicians who intervene who maintain and salvage these fistulas will grow in importance. This review aims to familiarize practitioners with the rationale for arteriovenous fistula creation, the detection of fistula dysfunction, and the state of the art on fistula maintenance and preservation. Current controversies are briefly reviewed.

Thoracic outlet decompression for subclavian venous stenosis after ipsilateral hemodialysis access creation

OBJECTIVE

Central venous stenosis is one of the most challenging complications in patients requiring hemodialysis. Venous thoracic outlet syndrome is an underappreciated cause of central venous stenosis in patients requiring dialysis that can result in failed percutaneous intervention and loss of a functioning dialysis access. Limited data exist about the safety and outcomes of first rib resection in patients requiring hemodialysis, and the results have been confounded by the various surgical approaches used. The purpose of the present study was to evaluate the safety, operative outcomes, and patency of the existing dialysis access after transaxillary thoracic outlet decompression.

METHODS

A retrospective medical record review was performed from January 2008 to December 2019 of patients who had undergone thoracic outlet decompression for subclavian vein stenosis with ipsilateral upper extremity hemodialysis access. The baseline characteristics and comorbidities were reviewed. The operative and postoperative course were evaluated. The survival and patency rates were analyzed using the life-table method and Kaplan-Meier curve.

RESULTS

A total of 18 extremities in 18 patients were identified. Their mean age was 59 ± 11 years, and 89% were men. A total of 13 fistulas and 5 grafts were included. All patients had undergone repair via a transaxillary approach. First rib resection, anterior scalenectomy, and circumferential venolysis were performed in all 18 patients. The mean operative time was 99 ± 19 minutes, with an estimated blood loss of 78 ± 66 mL. The median length of stay was 2 days. No patient had died at 30 days. The survival rate at 1 year was 83%. The primary, primary-assisted, and secondary patency at 1 year were 42%, 69%, and 93%, respectively.

CONCLUSION

Thoracic outlet decompression via the transaxillary approach is a technically feasible and safe operation in patients with ipsilateral upper extremity hemodialysis access. Patients with threatened dialysis access due to subclavian vein stenosis should be carefully evaluated for possible extrinsic compression at the costoclavicular junction. These patients might benefit from transaxillary first rib resection, scalenectomy, and venolysis.

A comparison of stenting versus hemodialysis reliable outflow graft for hemodialysis patients with recurrent central venous obstructions

BACKGROUND

Central venous occlusive disease is a common cause of upper extremity arteriovenous access dysfunction in hemodialysis patients. When refractory to balloon angioplasty, the treatment options include central venous stenting and hemodialysis reliable outflow (HeRO; Merit Medical, South Jordan, Utah) graft. The purpose of the present study was to evaluate the outcomes of these options.

METHODS

A retrospective review was performed of patients who had undergone central venous stenting or HeRO placement for central venous obstruction from December 2008 to March 2018. The primary outcomes were the reintervention rates, patency, and mortality.

RESULTS

A total of 75 hemodialysis patients were identified after failed balloon angioplasty for central venous obstruction. Of the 75 patients, 44 underwent central venous stenting comprising coverage of the subclavian vein (n = 27), innominate vein (n = 18), and/or superior vena cava (n = 5). Six stent patients later underwent HeRO placement. The stents used were stent grafts in 65% (Viabahn, n = 9; Fluency/Flair, n = 19; iCast, n = 2; and other, n = 1) and bare metal stents in 35% (Wall-stent, n = 6; Protégé, n = 1; Cobalt, n = 1; and other, n = 9). The remaining 31 patients underwent HeRO graft placement. The venous outflow component insertion sites were the internal jugular (n = 20), external jugular (n = 1), subclavian (n = 6), axillary (n = 2), and other (n = 2). The stent and HeRO groups were similar in the previous central venous intervention rates (median, 0.6 [interquartile range (IQR), 0-3.0]; vs median, 3.5 [IQR, 0-10.1] annually; P = .679). After the index procedure, no difference was found between the two groups in the frequency of dialysis circuit interventions annually (median, 2.0 [IQR, 0-6.0]; vs median, 2.0 [IQR, 0-7.0]; P = .291) nor central venous interventions (ie, angioplasty of the central veins or within the portion of the HeRO inside the central veins) annually (median, 2.0 [IQR, 0-4.1]; vs median, 0 [IQR, 0-2.4]; P = .419). The 1-year access circuit primary patency was 8.1% for stenting and 22.2% for HeRO (P = .109). The 2-year access circuit secondary patency was 40.0% for stenting and 52.4% for HeRO (P = .401). The all-cause mortality was similar at 1 year (3.7% vs 4.8%; P = .856) and 2 years (11.8% vs 23.5%; P = .368).

CONCLUSIONS

Central venous stenting and HeRO were shown to have similar rates of reintervention and patency. The results from the present study suggest that the multiple treatment options available for this problematic disease process can yield similar results when careful patient selection is applied.

Endovascular treatments of tunneled central venous catheter-induced superior vena cava complete occlusion via through-and-through technique

BACKGROUND

Superior vena cava occlusion (SVCO) induced by tunneled central venous catheter (tCVC) is an uncommon but challenging complication of hemodialysis patients. The aim of this study was to access the efficacy, safety, and patency of stents in tCVC-related SVCO via through-and-through technique.

METHOD

We retrospectively identified seven patients with benign SVCO secondary to tCVC treated with endovascular approaches successfully between 1 March 2013 and 31 October 2019. Patients' demographic data, clinical signs and symptoms, and imaging data were followed up and recorded.

RESULTS

Technical success was achieved in all cases. All the patients were performed with percutaneous transcatheter angioplasty (PTA) and subsequently stent placement via the through-and-through technique. During follow-up, four patients underwent secondary interventions, including PTA and/or stent placement. The primary patency after 3, 6, 9 and 12 months was 100%, 100%, 86% and 86%, and secondary patency after 12 months was 100%. No procedure-related deaths occurred.

CONCLUSIONS

Endovascular management of SVCO is a safe and effective approach. CT examination can provide a direction for endovascular treatment and periodic surveillance.

Successful stent implantation in the internal jugular vein occlusion using Brockenbrough needle under intravascular ultrasound guidance leading to prevention of vision loss in a hemodialysis patient with neovascular glaucoma

Central venous occlusion (CVO) remains an unresolved issue in hemodialysis patients. We herein present an interesting case of a 42-year-old hemodialysis female patient with complete vision loss in the left eye, who was at high risk of losing vision in her right eye because of neovascular glaucoma (NVG). Computed tomography (CT) showed occlusion of the right internal jugular vein (IJV) just above the junction with the right innominate vein. From the configuration and location of the lesion, it was concluded the occlusion had been caused by venous valvular degeneration. Her NVG with progressive intraocular pressure (IOP) elevation was presumably attributed to the right IJV occlusion. The extra-rigid occlusive lesion was successfully penetrated by means of a Brockenbrough needle and subsequently implanted with a balloon-expandable stent. Intravascular ultrasound (IVUS) guidance allowed us to manipulate the Brockenbrough needle safely. After stent implantation, the right IOP declined dramatically, resulting in the preservation of her eyesight. <Learning objective: Neovascular glaucoma (NVG) is a devastating disease for the occurrence of which various factors are responsible. In this report, the occlusion of the right internal jugular vein was determined as the main cause of the elevated intraocular pressure, which had led to the deterioration of her NVG. Stent implantation provided an immediate reduction in intraocular pressure. The Brockenbrough needle was safely manipulated under intravascular ultrasound guidance.>.

Efficacy of stent-graft placement to salvage central vein stents with recalcitrant restenosis in patients with arteriovenous fistulas

The purpose of this study was to determine the effectiveness and permanency of stent-graft placement to salvage stents with recalcitrant restenosis due to central vein stenosis (CVS). Between May 2014 and February 2016, VIABAHN stent-grafts were deployed in patients with functioning arteriovenous (AV) fistulas who underwent previous bare metal stent (BMS) placement and had recalcitrant stent restenosis that did not respond to percutaneous transluminal angioplasty (PTA). Surveillance was carried out at 3, 6, 12, 18, and 24 months with diagnostic fistulography. Fourteen patients initially underwent 15 BMS placements. In the follow-up period (range, 118-976 days), patients presented with symptomatic venous hypertension; subsequently, a total of 52 unsuccessful repeat PTAs for BMS restenosis were undertaken, and the median primary access survival of PTAs was 66 ± 43 days. For salvage, 14 stent-grafts were placed in segments with recalcitrant restenosis of a CVS stent. Within 1.25 ± 0.72 days after stent-graft placement, patients who initially presented with symptomatic venous hypertension reported complete resolution. The median primary access survival (mean, 1183 ± 312 days) was longer than PTAs alone (P < .01). No major or minor complications were associated with stent-graft deployment or any of the subsequent interventions in the study period. The primary patency rate at 6, 12, and 18 months was 100%, and it was 85.7% at 24 months. The secondary access patency rate was 92.9% at 24 months. In conclusion, stent-graft placement to salvage CVS stents with recalcitrant restenosis in patients with AV fistulas is safe and effective if PTAs fails to maintain luminal patency.

Outcome of Central Vein Occlusion Recanalization in Hemodialysis Patients and Predictors for Success: A Retrospective Study

Background:

Catheter-directed treatment is the standard approach for the management of chronic central venous occlusion.

Purpose:

The objective of this study is to report the outcome of conventional recanalization of chronic central vein occlusion in hemodialysis patients and to determine the predictors for success.

Material and Methods:

All hemodialysis patients who underwent endovascular recanalization of central vein occlusion from January 2012 to December 2016 were retrospectively evaluated. The procedure was percutaneous transluminal angioplasty. Stenting was performed in case of a significant recoil stenosis. Kaplan-Meier analysis was used to evaluate central vein patency. Univariate analysis and multivariate logistic regression were used to calculate the predictive factors.

Results:

Ninety-seven patients (mean age, 61.2 years; range, 25‒89 years old) with 97 central vein occlusions were enrolled. Technical success was achieved in 49 patients (50.5%). The primary patency rates of central veins at 6 and 12 months were achieved in 17 patients (34.4%) and 8 patients (15.8%), respectively. The assisted primary patency rates at 6 and 12 months were achieved in 38 patients (77.3%) and 30 patients (61%), respectively. Patient age ≥60 years and a tapered-type of lesion were significant predictive factors for successful recanalization.

Conclusion:

Endovascular treatment of the central vein occlusion using a conventional technique is moderately effective and safe. Angioplasty alone and stenting were not significantly different in terms of patency rate. The age of the patients and type of occlusion were significant predictors for successful recanalization.

KDOQI Clinical Practice Guideline for Vascular Access: 2019 Update

The National Kidney Foundation's Kidney Disease Outcomes Quality Initiative (KDOQI) has provided evidence-based guidelines for hemodialysis vascular access since 1996. Since the last update in 2006, there has been a great accumulation of new evidence and sophistication in the guidelines process. The 2019 update to the KDOQI Clinical Practice Guideline for Vascular Access is a comprehensive document intended to assist multidisciplinary practitioners care for chronic kidney disease patients and their vascular access. New topics include the end-stage kidney disease "Life-Plan" and related concepts, guidance on vascular access choice, new targets for arteriovenous access (fistulas and grafts) and central venous catheters, management of specific complications, and renewed approaches to some older topics. Appraisal of the quality of the evidence was independently conducted by using a Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach, and interpretation and application followed the GRADE Evidence to Decision frameworks. As applicable, each guideline statement is accompanied by rationale/background information, a detailed justification, monitoring and evaluation guidance, implementation considerations, special discussions, and recommendations for future research.

[Thoracic Central Venous Occlusive Disease and Haemodialysis Access]

Benign central venous thoracic occlusion is a frequent issue in haemodialysis patients. Symptomatic stenosis affects quality of life and can cause dysfunction of arteriovenous access or make it impossible to implant a haemodialysis catheter. Common risk factors for the development of the occlusions are central venous catheters and cardiac rhythm devices. The gold standard for diagnosis is venous angiography. Treatment of asymptomatic lesions can lead to clinical deterioration and should be avoided. The primary method of treatment for symptomatic patients is endovascular therapy. Repeat balloon angioplasty is a standard therapy. In case of elastic recoiling or early recurrence, placement of bare metal stent or stent graft could be considered. Surgical options should be preserved only for refractory cases. Further randomised trials are needed to prove the efficacy of new devices, such as dedicated venous stents and drug coated balloons.

Outcomes of the Gore Excluder abdominal aortic aneurysm leg endoprosthesis for treatment of central vein stenosis or occlusion in patients with chronic hemodialysis

OBJECTIVE

Central venous occlusive disease is a critical complication in long-term hemodialysis patients with arteriovenous (AV) dialysis circuits. The purpose of this retrospective, single-arm cohort study was to evaluate the effectiveness of an abdominal aortic aneurysm (AAA) contralateral leg endoprosthesis to treat symptomatic central venous occlusive diseases in patients with chronic hemodialysis.

METHODS

A prospective cohort study included 60 patients on hemodialysis presenting with central venous stenosis or occlusion, who were treated with a Gore Excluder AAA contralateral leg stent graft between December 2013 and July 2018. Follow-up angiography was obtained at 3, 6, and 12 months. The outcomes and duration of primary circuit and target site patency were measured from the time of the stent graft implantation to the first reintervention for AV circuit dysfunction and target site restenosis. Secondary patency was calculated from stent graft implantation to the point when AV access was no longer attainable.

RESULTS

Circuit primary patency rate was 54.9% at 1 year of Gore Excluder AAA contralateral leg or iliac extender stent grafts, implanted in 60 hemodialysis patients with central vein occlusive disease. Cumulative target site primary patency rate was 88.3% at 1 year. Secondary patency rate was 95% during follow-up. Patients with concomitant lesions had a significantly higher risk of circuit primary patency dysfunction.

CONCLUSIONS

Treatment of central vein obstructions in hemodialysis patients with stent grafts has been appealing owing to the tapered shape with a larger diameter and the availability of various lengths.

Analysis of the positional relationship between the left brachiocephalic vein and its surrounding vessels via computed tomography scan: A retrospective study

OBJECTIVES

This study aimed to clarify the positional relationship between the left brachiocephalic vein and its surrounding vessels and to analyse the association between this positional relationship and ageing.

METHOD

Chest contrast-enhanced computed tomography was performed for 100 adults. The contact number between left brachiocephalic vein and surrounding vessels (aorta, brachiocephalic artery, left common carotid artery and left subclavian artery) was determined. The correlations of ageing with the cross-sectional areas of left brachiocephalic vein crossing brachiocephalic artery and left common carotid artery and peripheral end of left brachiocephalic vein were analysed.

RESULTS

LBV was in contact with aorta in 19, brachiocephalic artery in 97, left common carotid artery in 90 and left subclavian artery in 21 patients. There were significant negative correlations of ageing with the cross-sectional areas of left brachiocephalic vein crossing brachiocephalic artery and left common carotid artery and peripheral end of left brachiocephalic vein.

CONCLUSIONS

Brachiocephalic artery and left common carotid artery have easy contact with left brachiocephalic vein. There was a negative relationship between the cross-sectional area of left brachiocephalic vein and age.

Comparison of Percutaneous Transluminal Angioplasty with Stenting for Treatment of Central Venous Stenosis or Occlusion in Hemodialysis Patients: A Systematic Review and Meta-analysis

OBJECTIVES

A common cause of hemodialysis vascular access dysfunction, a primary cause of morbidity and mortality in patients undergoing hemodialysis, is central venous stenosis or occlusion. The present study compared percutaneous transluminal angioplasty (PTA) with percutaneous transluminal angioplasty and stent placement (PTS) for treatment of central venous stenosis or central vein occlusion in hemodialysis patients.

METHODS

A systematic literature review was conducted using database searches of PubMed, Cochrane, and Embase. Articles were selected using the Population/Intervention/Comparator/Outcomes (PICO) process. Outcomes included the rate of procedural success, primary patency, assisted primary patency, re-intervention subjects, re-intervention rate, and adverse events.

RESULTS

A total of eight studies were included in the meta-analysis with subjects in the PTA group (n = 281) or PTS group (n = 192). Primary patency rate between PTA and PTS groups at 3-, 6-, 12-, or 24-month follow-up was not different (all p > 0.05). Patients treated with PTA had greater assisted primary patency rates than the PTS group (OR = 1.03, 1.73, 1.03, and 2.00 at 3, 6, 12, and 24 months, respectively). However, the statistical assessment only showed significantly at 24-month follow-up (p = 0.01).

CONCLUSIONS

The present meta-analysis revealed that, compared to PTS, PTA may provide increased assisted primary patency for endovascular treatment of central vein stenosis or occlusion in patients undergoing hemodialysis.

LEVEL OF EVIDENCE

Level 3a.

Radiofrequency wire technique and image fusion in the creation of an endovascular bypass to treat chronic central venous occlusion

The goal of this case report was to demonstrate the feasibility, safety, and efficacy of image fusion software to treat symptomatic central venous occlusion with radiofrequency wire after failure of conventional endovascular techniques. The complex and chronic central venous occlusion was successfully treated without complications. The combination of these techniques provided an endovascular solution and could be considered in select cases.

Long-segment central venous occlusion in a hemodialysis patient treated by segmented sharp recanalization strategy: A case report

INTRODUCTION

Among hemodialysis population, central vein occlusion (CVO) is a common complication. Percutaneous transluminal angioplasty has become the mainstay treatment these days. But the treatment of long-segment central venous occlusion remains difficult.

PATIENT CONCERNS

We presented a 73-year-old man on maintenance hemodialysis complaining of swelling of the right arm and face for 20 days. The patient underwent maintenance hemodialysis via a right internal jugular vein catheter for first 2 months of dialysis while the initial right radiocephalic wrist arteriovenous fistula (AVF) blood flow had been unsatisfactory (below 180 mL/min) for 1 month.

DIAGNOSIS

Digital subtraction angiography revealed long-segment CVO extending from the right subclavian vein (SV) to the right innominate vein (IV), forming an obvious included angle at the right jugular angle.

INTERVENTIONS

Since conventional guide wire transversal failed, segmented sharp recanalization was performed by separate transversal of the obstructive right SV and right IV, therefore crossing the whole lesion segment by segment, followed by balloon dilation and stent placement.

OUTCOMES

No procedure-related complication was recorded during or after the operation. After a follow-up period of 5 months, the patient's AVF maintained satisfactory in blood flow, while the edema in his ipsilateral limb and face also notably ameliorated.

CONCLUSION

The segmented sharp recanalization is a practical strategy in treating angled long-segment CVO which is refractory to traditional guide wire transversal in hemodialysis patients.

Spanish Clinical Guidelines on Vascular Access for Haemodialysis

Vascular access for haemodialysis is key in renal patients both due to its associated morbidity and mortality and due to its impact on quality of life. The process, from the creation and maintenance of vascular access to the treatment of its complications, represents a challenge when it comes to decision-making, due to the complexity of the existing disease and the diversity of the specialities involved. With a view to finding a common approach, the Spanish Multidisciplinary Group on Vascular Access (GEMAV), which includes experts from the five scientific societies involved (nephrology [S.E.N.], vascular surgery [SEACV], vascular and interventional radiology [SERAM-SERVEI], infectious diseases [SEIMC] and nephrology nursing [SEDEN]), along with the methodological support of the Cochrane Center, has updated the Guidelines on Vascular Access for Haemodialysis, published in 2005. These guidelines maintain a similar structure, in that they review the evidence without compromising the educational aspects. However, on one hand, they provide an update to methodology development following the guidelines of the GRADE system in order to translate this systematic review of evidence into recommendations that facilitate decision-making in routine clinical practice, and, on the other hand, the guidelines establish quality indicators which make it possible to monitor the quality of healthcare.

Symptomatic superior vena cava syndrome in hemodialysis patients: mid-term results of primary stenting

This clinical report details the results of endovascular treatment of symptomatic superior vena cava syndrome due to central vein stenosis or obstruction (CVSO) by stent angioplasty in patients with dialysis-dependent end-stage renal disease. A 3-year retrospective review of two institutional registries identified 25 chronic hemodialysis patients (17 men, 8 women) affected by CVSO who received endovascular treatment. The majority of the patients (n = 19) presented with symptomatic arm, breast, and facial swelling; and 6 patients presented with dialysis-access dysfunction and venous-line hypertension. The etiology of CVSO was before central venous catheter in all but 2 patients. Venography showed 19 cases of stenosis (4 stenoses of superior vena cava, 3 brachiocephalic, 10 subclavian, and 2 axillary veins) and 6 occlusions of the superior vena cava. After percutaneous transluminal angioplasty and primary stent angioplasty, there was an immediate regression of symptoms and arteriovenous fistula preservation in 21 cases; 4 patients received a new arteriovenous fistula after interventional treatment. No procedural major complications or patient deaths occurred. During the follow-up period, we recorded a primary patency rate of 95%, 80%, and 70%, respectively, at 6, 12, and 18 months; and a secondary patency rate of 100%, 95%, and 90%, respectively, at 6, 12, and 18 months. In conclusion, endovascular treatment with primary stenting has proven to be a durable treatment option for hemodialysis patients with CVSO, and this treatment should be considered before dialysis access placement in patients with catheter-induced central vein obstruction.

Treatment of central venous in-stent restenosis with repeat stent deployment in hemodialysis patients

Purpose

To report patency rates for stent deployment for treatment of in-stent stenosis of the central veins of the chest in hemodialysis patients.

Materials and Methods

A retrospective analysis was performed on 29 patients who underwent 35 secondary percutaneous transluminal stent (PTS) deployments for in-stent stenosis within the central veins that were refractory to angioplasty and ipsilateral to a functioning hemodialysis access (in-stent PTS group). For comparison, patency data were acquired for 47 patients who underwent 78 successful percutaneous transluminal angioplasty (PTA) procedures for in-stent stenosis (in-stent PTA group) and 55 patients who underwent 55 stent deployments within native central vein stenosis refractory to angioplasty (native vein PTS group).

Results

The 3-, 6-, and 12-month primary lesion patency for the in-stent PTS group was 73%, 57%, and 32%, respectively. The 3-, 6-, and 12-month primary patency for the in-stent PTA group was 70%, 38%, and 17% and for the native vein PTS group was 78%, 57%, and 26%, which were similar to the in-stent PTS group (p = 0.20 and 0.41, respectively). The 3-, 6-, and 12-month secondary access patency was 91%, 73%, and 65% for the in-stent PTS group. Sub-analysis of the in-stent PTS group revealed no difference in primary (p = 0.93) or secondary patency rates (p = 0.27) of bare metal stents (n = 23) compared with stent grafts (n = 12).

Conclusions

Stent deployment for central vein in-stent stenosis refractory to angioplasty was associated with reasonable patency rates, which were similar to in-stent PTA and native vein PTS.

Venoplasty of a chronic venous occlusion allowing for cardiac device lead placement: A team approach

In patients with complete venous occlusion requiring venous access for cardiac device lead placement, venous revascularization is a viable option. A percutaneous approach to venous revascularization has gained popularity. This method reduces patient exposure to more invasive therapies. In this case series, we describe two cases of a total venous occlusion that were successfully revascularized using a “wire externalization” technique. This technique requires the use of antegrade and retrograde access.

Magnetic resonance venography and three-dimensional image fusion guidance provide a novel paradigm for endovascular recanalization of chronic central venous occlusion

OBJECTIVE

Endovascular recanalization is considered first-line therapy for chronic central venous occlusion (CVO). Unlike arteries, in which landmarks such as wall calcifications provide indirect guidance for endovascular navigation, sclerotic veins without known vascular branching patterns impose significant challenges. Therefore, safe wire access through such chronic lesions mostly relies on intuition and experience. Studies have shown that magnetic resonance venography (MRV) can be performed safely in these patients, and the boundaries of occluded veins may be visualized on specific MRV sequences. Intraoperative image fusion techniques have become more common to guide complex arterial endovascular procedures. The aim of this study was to assess the feasibility and utility of MRV and intraoperative cone-beam computed tomography (CBCT) image fusion technique during endovascular CVO recanalization.

METHODS

During the study period, patients with symptomatic CVO and failed standard endovascular recanalization underwent further recanalization attempts with use of intraoperative MRV image fusion guidance. After preoperative MRV and intraoperative CBCT image coregistration, a virtual centerline path of the occluded segment was electronically marked in MRV and overlaid on real-time two-dimensional fluoroscopy images. Technical success, fluoroscopy times, radiation doses, number of venograms before recanalization, and accuracy of the virtual centerline overlay were evaluated.

RESULTS

Four patients underwent endovascular CVO recanalization with use of intraoperative MRV image fusion guidance. Mean (± standard deviation) time for image fusion was 6:36 ± 00:51 mm:ss. The lesion was successfully crossed in all patients without complications. Mean fluoroscopy time for lesion crossing was 12.5 ± 3.4 minutes. Mean total fluoroscopy time was 28.8 ± 6.5 minutes. Mean total radiation dose was 15,185 ± 7747 μGy/m², and mean radiation dose from CBCT acquisition was 2788 ± 458 μGy/m² (18% of mean total radiation dose). Mean number of venograms before recanalization was 1.6 ± 0.9, whereas two lesions were crossed without any prior venography. On qualitative analysis, virtual centerlines from MRV were aligned with actual guidewire trajectory on fluoroscopy in all four cases.

CONCLUSIONS

MRV image fusion is feasible and may improve success, safety, and the surgeon's confidence during CVO recanalization. Similar to arterial interventions, three-dimensional MRV imaging and image fusion techniques could foster innovative solutions for such complex venous interventions and have the potential to affect a great number of patients.

The feasibility and safety of a through-and-through wire technique for central venous occlusion in dialysis patients

Background

To retrospectively compare the operation time, success rate and efficacy between unidirectional and bidirectional procedures in the treatment of central venous occlusion diseases (CVOD), assess the advantages of the bidirectional approach, and determine the characteristics of CVOD appropriate for the bidirectional approach treatment.

Methods

A total of 49 patients who underwent endovascular interventions with all relevant data between January 2011 and December 2015 at the First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China, were included in this retrospective study, and were categorized into two groups: the 19 patients in group 1 had undergone percutaneous transluminal venoplasty (PTV) via a conventional technique (unidirectional procedure from the vein distal or proximal to the obstructive lesion), and the 30 in group 2 had undergone flossing wire technique (bidirectional procedure from femoral vein and the vein distal to obstructive lesion and using a flossing wire technique). The technical success rate, the fluoroscopy time in the procedure, perioperative complications, and patency were evaluated retrospectively.

Results

Compared with group 1, group 2 had a higher initial technical success rate (83.33% vs. 47.36%, p = 0.012) but a shorter fluoroscopy time (82.6 ± 26.1 vs. 116.1 ± 42.1, p = 0.048). Receiver operating characteristic (ROC) analysis indicated that a lesion with a length of 6.5 cm was the best predictor of technique success (p = 0.02) in group 1, but no cut-off value was identified for group 2. There were no significant differences in perioperative complications between these two groups. The complication rates were 31.58% (6/19) in group 1 and 6.67% (2/30) in group 2, (p = 0.043), respectively. No significant difference was observed between these two groups with respect to the stent patency rate.

Conclusion

Compared with the conventional technique, the flossing wire technique has a higher success rate, shorter fluoroscopy time, fewer complications and similar patency rate. It is a feasible treatment for CVOD, especially for long obstructive lesions.

Comparison of Open-Cell Stent and Closed-Cell Stent for Treatment of Central Vein Stenosis or Occlusion in Hemodialysis Patients

Background

Central vein stenosis or occlusion is a common complication that can lead to significant morbidity and dysfunction of access in the hemodialysis patient. More lesions can develop over time, and preserving access becomes a challenge as life expectancy of the hemodialysis patient increases.

Objectives

The goal was to compare long-term results and determine the outcomes of open-cell stent versus closed-cell stent for central vein stenosis or occlusion in hemodialysis patients.

Patients and Methods

From 1997 to 2015, in 401 hemodialysis patients, stent placement for central vein stenosis or occlusion was performed if balloon angioplasty was unsatisfactory, due to elastic recoil or occurrence of restenosis within 3 months. When thrombus was present, primary stenting was performed. A total of 257 open-cell stents and 144 closed-cell stents were used. Angiographic findings including lesion site, central vein stenosis or occlusion, and presence of thrombosis and complication were evaluated. Primary patency rate and mean patency rate of the stent were compared between two stent groups by Kaplan-Meier survival analysis.

Results

For the open-cell stent group, 159 patients were diagnosed as central vein stenosis and 98 were occlusion. For the closed-cell stent group, 78 were stenosis and 66 were occlusion. There were two complications for central migration and two for procedure-related vein rupture. Open-cell stents and closed-cell stents had mean patency rates of 10.9 ± 0.80 months and 8.5 ± 10.87 months, respectively (P = 0.002).

Conclusion

The open-cell stent is effective and its performance is higher than that obtained with the closed-cell stent for treating central vein stenosis or occlusion in hemodialysis patients.

Brachiocephalic Vein Stenting and Body-Floss Technique as a Treatment of CVD in Dialysis-Dependent Patient - Case Report and Literature Review

Background

Given the increasing number of elderly hemodialysis-dependent patients with concomitant chronic diseases the successful creation and maintenance of reliable vascular access become a real challenge. In current literature central vein disease (CVD) is defined as at least 50% narrowing up to total occlusion of central veins of the thorax including superior vena cava (SVC), brachiocephalic (BCV), subclavian (SCV) and internal jugular vein (IJV). The incidence of CVD has been reported to be as high as 23% in the total dialysis population and 41% in those with access related complains.

Case Report

61-year-old man has been admitted to the local radiology department with symptoms of the superior vena cava syndrome. The venography revealed occlusion of the right brachiocephalic vein. Due to Tortuosity and lack of stamp of right subclavian vein contributed to the decision to perform recanalization by “body floss” technique. In a further step we have performed PTA of obstructed vein segment using 7×40 mm balloon. Due to the presence of residual stenosis it was decided to implant two self – expanding stents 10×40 mm. After the procedure the patient was discharged in good condition and transferred to dialysis center.

Conclusions

Main objective was the salvage of a functioning arteriovenous fistula. Performed endovascular intervention is a safe and effective approach to correct CVD for a short term. To ensure long lasting effects the patient will require enhanced follow-up and inevitable reinterventions. For that matter, prevention of CVD remains critical.

Comparison of two Endovascular Treatments of a Stenosed Arteriovenous Fistula: Balloon-Angioplasty with and without Stenting

Purpose

Arteriovenous fistulas (AVFs) are created in patients to enable a permanent vascular access for hemodialysis. The AVF causes changes in the hemodynamic conditions leading to possible complications, stenoses being the most common one. Our objective was to compare the effect of treating the stenosed AVF by balloon-angioplasty, whether followed or not with stenting.

Methods

We considered an AVF presenting an 60% arterial stenosis and simulated the two endovascular treatments using an implicit approach. We then simulated the fluid-structure interactions (FSI) within (i) the patient-specific stenosed AVF, (ii) the AVF after angioplasty, and (iii) the AVF after angioplasty plus stenting with ANSYS Workbench.

Results

We show that a self-expandable stent does not modify the curvature of the vessel after angioplasty; it only increases the local Young modulus of the stented wall by an order of magnitude. The results of the FSI simulations indicate that the two treatments induce the same hemodynamic conditions: they both reduce the pressure difference across the stenosis, while maintaining the flow distribution downstream of the stenosis. The venous flow rate that has to be guaranteed for hemodialysis is unaltered. Thanks to its large axial flexibility, the self-expandable stent causes at maximum a three-fold increase in the internal wall stresses at peak systole as compared to angioplasty alone.

Conclusions

By maintaining the vessel lumen shape over time, the stent is likely to reduce the risk of restenosis that can otherwise occur after balloon-angioplasty because of the viscoelastic recoil of the vessel.

Stent grafts for central venous occlusive disease in patients with ipsilateral hemodialysis access

PURPOSE

To assess long-term outcomes of stent grafts in patients with symptomatic central venous stenoses and occlusions ipsilateral to hemodialysis grafts or fistulas.

MATERIALS AND METHODS

The study included 52 of 55 consecutive patients with symptomatic stenoses of the central veins draining upper limb dialysis access grafts or fistulas treated with stent grafts. Indications for stent grafts were poor angioplasty results, rapid recurrence, or total occlusion. Endpoints were lesion patency and access patency following intervention. Mean follow-up was 25 months with a median of 24 months and 1.25 additional procedures per patient year. Patency rates were calculated using Kaplan-Meier analysis.

RESULTS

All stent grafts were successfully deployed. The lesion patency rates at 6, 12, 24, and 36 months after intervention were 60%, 40%, 28%, and 28%. The access patency rates at 6, 12, 24, and 36 months after intervention were 96%, 94%, 85%, and 72%. There was one major complication and no minor complications. In 40 patients (77%), the internal jugular vein confluence was covered by the stent graft. In five patients, the dialysis circuits became occluded, with no clinical sequelae in four; one patient was lost to follow-up. The contralateral brachiocephalic vein was covered in three patients (6%), preventing contralateral access construction in one patient.

CONCLUSIONS

Central vein stent graft placement in patients with hemodialysis access is associated with prolonged access patency. Coverage of major vein confluences, which occurred in 83% of the patients in this series, can compromise future access and should be avoided whenever possible by careful technique.

Central vein stenosis

Central vein stenosis (CVS) is commonly seen in patients receiving hemodialysis through an arteriovenous access, threatening the usability of arteriovenous access for dialysis. Subclavian and internal jugular catheters are prime reasons for the development of CVS, especially in the setting of long-term use of multiple catheters. CVS related to cardiac rhythm devices also is seen frequently. Idiopathic CVS can be encountered, although it is less common. Clinical features ultimately become sufficiently prominent to prompt angiographic evaluation. CVS should be evaluated carefully because management must be individualized. The primary method for treatment of CVS is endovascular intervention, including angioplasty and stent placement, whereas surgical options should be pursued in only refractory cases due to the invasiveness of the intervention. Early referral of patients for chronic kidney disease care; timely discussion of kidney replacement modality choices, including nonhemodialysis options such as peritoneal dialysis and kidney transplantation; placement of arteriovenous access prior to the onset of dialysis; and avoidance of catheters and other central vein instrumentation will prevent the development of CVS in most patients with kidney disease.

Endovascular stenting for left subclavian venous stenosis for a hemodialysis patient with a persistent left superior vena cava

A persistent left superior vena cava (PLSVC) is the most common thoracic venous anomaly, and we should be aware of its existence. We encountered a case of significant left arm swelling due to recurrent left subclavian venous stenosis in a hemodialysis patient with a PLSVC. Endovascular stent placement was performed safely and effectively for the stenosis employing the pull-through technique, in which a guidewire was passed from the left internal jugular vein to the access vein. On the following day, left arm swelling had improved. 3 months after stent placement the left arm swelling has not recurred.

Use of covered stents in the central vein: a feasibility study in a canine model

PURPOSE

To evaluate the feasibility of using covered stents vs. bare stents in a model of central vein stenosis with an arteriovenous graft created to mimic the conditions in hemodialysis patients.

METHODS

In 7 mongrel dogs, an expanded polytetrafluoroethylene-covered nitinol stent was placed in one common iliac vein and a bare stent was placed in the contralateral vein. Arteriovenous grafts were created bilaterally between the common femoral artery and vein to induce endothelial damage. Neointima formation in the covered stents was compared to the bare stents at 12 weeks using microscopy and histochemical staining.

RESULTS

Two dogs were excluded due to thrombosis and infection of the arteriovenous grafts, but all stents in the remaining 5 dogs were patent. Smooth, complete neointimal coverage was observed on the inner surface of all the covered stents without intraluminal thrombus. In contrast, incomplete neointimal coverage was seen in all bare stents, with small focal thrombi adhering to the neointima on 3 bare stents. Focal nodular neointimal hyperplasia with denudation of the endothelium was observed in only 2 bare stents. Mean neointimal thickening was significantly greater in the covered stents. Eccentric neointimal thickening was observed at the inflow and outflow segments of both types of stents.

CONCLUSION

Covered stents are technically feasible for the treatment of central vein stenosis, and they demonstrate complete, smooth neointimal coverage in normal central veins, but they also display greater neointimal thickening than bare stents.

Is unilateral breast enlargement always a sign of cancer?

Breast swelling is caused by many etiological factors, but should alert central vein occlusion in hemodialysis patients when the permanent vascular access is in the same arm. The swelling of the breast is caused by venous hypertension in the venous plexus draining the breast. Endovascular treatment relieves venous hypertension and related clinical signs. Additional diagnostic workup or invasive interventions such as a biopsy should be avoided in such patients, as diagnosis is straightforward with the presence of a functioning arteriovenous fistula in the same arm.