Endovascular interventions for central vein stenosis

Evaluation of a new Everolimus-coated balloon catheter in an in-vivo porcine peripheral venous model

BACKGROUND

The venous uptake following the application of Everolimus-coated balloons is under reported. We evaluated the feasibility, safety, and Everolimus (EVR) deliverability of a novel non-commercially available Everolimus-Coated Balloon (ECB) catheter in a swine healthy peripheral vein model.

METHODS

In total 12 ECBs (5.0 μg/mm2) were inflated in 12 venous segments. The primary feasibility endpoint was the successful application of the ECB at the target venous sites. The primary efficacy endpoint was the successful drug uptake by the target venous tissue at 24 h and 7 days, assessed by High Performance Liquid Chromatography combined with tandem mass spectrometry. The primary safety endpoint was freedom from major adverse events.

RESULTS

Everolimus was detected in 10 out of 12 (83.33%) tissue samples (all six tissue samples at 24 h post-intervention and in four out of six samples at 7 days). The mean weight of the examined tissue was 0.20604 ± 0.29822 g (range: 0.37475-0.02229 g). The average EVR tissue content detected at 24 h (135.67 ± 204.95 μg/g) was numerically superior, but non-statistically significant to the that detected 7 days post-procedure (96.85 ± 110.89 μg/g). The average quantity of EVR on the balloon after retrieval was 33.9% of the initial drug dose. No adverse events were recorded, and no abnormalities were noted during autopsy.

CONCLUSIONS

The newly developed ECB successfully delivered Everolimus within the healthy venous wall. No adverse events were noted at a short-term follow-up.

RELEVANCE STATEMENT

These safety and feasibility results justify further experimental and clinical research to demonstrate the safety efficacy the specific balloon catheter.

Endovascular intravascular intervention for central venous stenosis in maintenance hemodialysis patients: a retrospective observational study

Background

The number of people undergoing maintenance hemodialysis is increasing rapidly worldwide. Central vein stenosis (CVS) is a common vascular complication in undergoing hemodialysis, especially those with a history of catheterization. This study aimed to investigate the characteristics of CVS and the clinical effectiveness of percutaneous transluminal angioplasty (PTA) alone and sequential percutaneous transluminal stenting (PTS) in hemodialysis patients with CVS.

Methods

A retrospective analysis of 26 cases of endovascular intervention for CVS using PTA alone or sequential PTS was performed. The characteristics of CVS and the clinical effectiveness of these procedures were evaluated.

Results

This study included 26 hemodialysis patients who presented with symptomatic CVS. Of these 26 patients, 53.85% were male, and their mean age was approximately 54.96 years. All the patients had a history of catheter placement or pacemaker implantation. The incidence of brachiocephalic vein stenosis was significantly higher than that of subclavian vein stenosis (46.16% vs. 26.92%). Based on the degree of stenosis and elastic retraction, these patients were administered PTA alone or sequential PTS. There was no difference in patient age, hemodialysis time, catheter retention time, or stenosis length between the PTA alone and sequential PTS groups. However, the degree of venous stenosis in the PTS group was more severe than that in the PTA alone group. The primary patency rates in the sequential PTS and PTA alone groups were 94.12% and 100% at 3 months; 88.24% and 88.89% at 6 months; 75.00% and 85.71% at 9 months; and 66.67% and 71.43% at 12 months, respectively. It is worth noting that for 7 patients with complete occlusion of the brachiocephalic vein, we used sharp recanalization technology and stenting placement, with patency rates of 85.71% and 71.43% at 6 and 12 months, respectively.

Conclusions

PTA alone is recommended for patients with less than 50% central venous elastic retraction, while sequential PTS is recommended for patients with ≥ 50% central venous elastic retraction. PTA and PTS are safe and effective methods for the treatment of CVS in patients undergoing hemodialysis.

Patency rates following treatment with the WRAPSODY™ Cell-Impermeable Endoprosthesis for recalcitrant renal access circuit dysfunction: Results from a tertiary Australian centre

OBJECTIVE

To describe clinical outcomes associated with the use of the WRAPSODY Cell-Impermeable Endoprosthesis at a tertiary center in Western Australia.

METHODS

Patients with recalcitrant occlusive disease in the venous outflow of their arteriovenous access circuits were treated with WRAPSODY. Patients were prospectively followed up to 12-month post-procedure. Study measures included 30-day adverse events, technical success, target lesion primary patency, access circuit primary patency, and assisted access circuit primary patency.

RESULTS

Twenty-seven WRAPSODY devices were used to treat 15 consecutive patients. The technical success rate was 100%. No device-related adverse events were observed during the follow-up period. Two patients did not complete the full follow up. Patency rates at 3-, 6-, and 12 months for target lesion primary patency were 100% (15/15), 100% (15/15), and 100% (13/13), respectively. Rates for access circuit primary patency at 3-, 6-, and 12 months were 73.3% (11/15), 46.7 % (7/15), and 46.2% (6/13), respectively. Edge stenosis was observed in 33.3% (5/15) of cases and accounted for 5 of the 8 patients who experienced failed access circuit primary patency on angiogram. Primary assisted functional patency was 100% at 12 months.

CONCLUSION

WRAPSODY can be utilized safely and has durable patency in real-world patients with complex anatomical renal access stenotic lesions. The therapeutic benefits associated with the device may encourage broader use in clinical practice.

Recanalization of a long segment occluded superior vena cava by puncturing the remnant calcified fibrin sheath of the internal jugular vein: A case report

A fibrin sheath with central venous occlusion is a common complication after central venous catheterization, and these patients often experience catheter dysfunction. A calcified fibrin sheath can cause a catheter to be stuck, and typically necessitates catheter removal or replacement. From another point of view, a calcified fibrin sheath can be seen in ultrasound and computed tomography, and the original fibrin sheath channel between the internal jugular vein and the atrium is unusually strong. When central vein occlusion occurs, the remnant calcified fibrin sheath of the internal jugular vein can be punctured under ultrasound guidance, allowing the guidewire to enter the atrium directly through the fibrin sheath. Here, we report a case in which we achieved easy recanalization of a long segment occluded superior vena cava by puncturing the remnant calcified fibrin sheath of the internal jugular vein.

Patient-specific hemodynamic feature of central venous disease intervened by stent: A numerical study

Central venous disease (CVD) with stenosis or occlusion is a severe and prevalent complication for chronic hemodialysis (HD) patients, resulting in dialysis access dysfunction. Percutaneous transluminal angioplasty with stent placement (PTS) has become one of the first-line treatments for CVD. In clinical practice, the extra stents would be used if the curative efficacy of a single stent were unsatisfactory. Aiming to evaluate the therapeutic effect of different PTS schemes, computational fluid dynamics (CFD) simulations on four patients were performed to compare the hemodynamic characteristics of real-life HD patients after stent placement. The three-dimensional central vein's models of each patient were built using computational tomography angiography (CTA) images, and idealized models were constructed as contrast. Two inlet velocity modes were imposed to imitate the blood flow rate of healthy and HD patients. The hemodynamic parameters for different patients were investigated, including wall shear stress (WSS), velocity, and helicity. The results showed that the implantation of double stents is able to improve flexibility. When subjected to external force, the double stents have better radial stiffness. This paper evaluated the therapeutic efficacy of stent placement and provided a theoretical basis for CVD intervention in hemodialysis patients.

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.

Most complex brachiocephalic vein occlusion in hemodialysis patients can be treated with simple endovascular techniques in an office-based angiosuite

OBJECTIVE

Brachiocephalic vein (BCV) obstruction can cause dialysis access dysfunction and failure. Central vein stenosis involving the BCV may require advanced endovascular procedures. We report that most BCV occlusions can be treated using simple endovascular techniques on an outpatient basis.

METHODS

From January 2009 to January 2022, 115 hemodialysis patients underwent BCV endovascular revascularization. Seventy-three of the initial procedures were performed in an office-based angiosuite. Indications for the procedure were BCV occlusion endangering the performance of a previous arm access or making the creation of a new arm access unadvisable. We recorded and analyzed risk factors and procedural results, patency rates, complications, and mortality.

RESULTS

The median age was 62 years (range, 23-91 years); 56% were female. Most prevalent associated conditions were diabetes mellitus (61%) and hypertension (68%). Fifty-six patients (48.7%) presented with severe upper extremity edema ipsilateral to the side of pre-existing functioning access. Obstruction recanalization was effective using standard catheter and wire in 106 cases (92.1%) and transseptal needle in nine cases (7.8%), that included seven using inside-out procedure. Initial management of the BCV stenosis was percutaneous transluminal balloon angioplasty alone in 74 patients (64.3%), stenting in 33 (28.7%), and HeRO conduit in eight cases (7%). Treatment of other central venous lesions included 49 cases (42.6%). The procedure was successful in 99.1% of patients. No intraoperative complications occurred. All 92 patients with previous arm access maintained adequate performance (100%). In 22 of 23 patients (95.6%), new upper extremity access creation was effectively performed after the venous intervention. Overall clinical success rate was 92%. The mean postoperative monitoring was 23 months, the median was 12 months, and the range was 1 to 84 months. During this monitoring period, 266 endovascular procedures, 91% in the office and 9% in the hospital, were required to preserve access performance. Eventually, 49 patients (42.6%) were stented. Eleven patients (9.56%) had infections, and six required complete access removal. Other causes of access failure included two patients with central vein thrombosis and one with massive pulmonary embolus. At the end, nine patients (7.8%) had access failure. Thirty-two patients (27.8%) died of unrelated causes during the follow-up period. Seventy-six patients (66%) have maintained functional access. Kaplan-Meier curves determined median primary patency of 9.6 months, median primary assisted patency of 56.2 months, and secondary patency of 75% at 80 months.

CONCLUSIONS

Successful endovascular revascularization of BCV obstruction can be treated safely, with simple endovascular techniques in an office-based context with minor complication rates and durable results.

Development of Central Venous Stenosis Upon ICD Implantation in Dialysis Patients: A Non-Negligible Issue

Background

In hemodialysis patients, implantable cardioverter-defibrillator (ICD) implantation may result in central venous stenosis (CVS) with associated symptoms, such as pain, edema of the ipsilateral arm, facial edema, and loss of dialysis access. However, literature concerning CVS in dialysis patients with a cardiac implantable electronic device is scarce.

Methods

We conducted a prospective cohort study in which we investigated the incidence of CVS in end-stage renal disease patients on chronic dialysis who received an ICD as part of participation in the randomized ICD2 trial. A venography was performed before ICD implantation and at 1 year follow-up.

Results

Between 2007 and 2017, 80 patients on dialysis received an ICD according to ICD2 trial protocol. Our population mainly consisted of males (76.3%), and had a median age of 67 years. Hemodialysis was the predominant dialysis modality (71.3%). The ICD was implanted in the right pectoral region in 58 patients (72.5%). A minority of the patients (27.5%) had a history of central venous catheters use, ipsilateral to ICD implantation site. Median follow-up was 16 months (IQR 13-35). Prospective assessment of central vein patency was possible in 56 patients (70.0%). Partial obstruction of central vein at follow-up was present in 19 out of 56 patients (33.9%) and complete occlusion in 4 patients (7.1%). With a complete clinical follow-up of all patients with a median duration of 3.5 years (IQR 2.7 - 6.3), 3 patients developed clinically significant symptoms of CVS.

Conclusions

Development of CVS in patients on chronic dialysis who received an ICD is a cause of concern. Prevention of such complications deserves attention and further research.

Trial Registration

ISRCTN20479861.

One-year outcomes and predictive factors for primary patency after stent placement for treatment of central venous occlusive disease in hemodialysis patients

Objective:

The study purpose was to determine the outcomes and factors predictive of primary stent patency for the treatment of central venous occlusive disease (CVOD) in hemodialysis patients.

Methods:

Data of 71 patients with CVOD treated with stent placement from January 2012 to December 2017 were analyzed. Univariate and multivariate analysis was performed to determine factors associated with stent patency. Adverse events related to stent placement were also examined.

Results:

The median primary patency duration of the 71 patients was 16 ± 2.2 months. The cumulative 3-, 6-, 9-, and 12- month primary patency rates were 93%, 72%, 55%, and 51%, respectively. Independent predictors of longer primary patency were vessel diameter > 12 mm, the use of a covered stent, and absence of vessel calcifications. Median primary patency of covered stents was 21 months as compared with only 10 months for bare stents (p < 0.001). Procedure-related adverse events occurred in 17 patients (21.8%), and four events (5.1%) required medical intervention. No life-threaten complications occurred.

Conclusions:

A vessel diameter > 12 mm, the use of a covered stent, and no vessel calcifications are independently associated with a higher primary patency rate after treatment of CVOD in hemodialysis patients.

Computational fluid dynamics simulation of hemodynamic changes in a hemodialysis patient with central venous stenosis treated with stent

BACKGROUND

It has not been demonstrated that computational fluid dynamics (CFD) can be used to model central venous stenosis (CVS), nor that hemodynamic changes in CVS treated with stent placement can be anticipated. The purpose of this study was to demonstrate the hemodynamic performance of CVS patients treated with stent placement.

METHODS

Patient-specific geometric models were constructed using computed tomography images of veins from hemodialysis patients treated with stent placement. CFD simulation based on geometry was performed using ANSYS-15 to compare pressure quantitatively, wall shear stress (WSS), and flow velocity in the brachial vein before and after stent placement.

RESULTS

Following a covered stent placement, the swelling of the left upper extremity was relieved. Prior to stent implantation, the maximum and mean brachial vein wall pressures were 465.2 Pa and 224.609 Pa, respectively. It was determined that the maximum WSS value was 8.449 Pa and that the mean WSS value was 0.743 Pa. The maximum and mean flow velocities were 1.16 and 0.173 m/s, respectively. After stent placement, the maximum wall pressure, maximum WSS, and maximum flow velocity dropped by 59.4%, 71.2%, and 57.8%, respectively. The mean wall pressure, mean WSS, and mean flow rate decreased by 43.5%, 52.7%, and 17.6%, respectively.

CONCLUSION

Hemodynamics of CVS in hemodialysis patients exhibited turbulent, imbalances and disorders, which can be improved by stent placement.

Role of Endovascular Treatment in Dysfunctional Hemodialysis Fistulae: A Single Center Experience

Introduction

Arteriovenous fistulas (AVFs) are the preferred route of hemodialysis in end-stage renal disease. However, recurrent patency loss is an obstacle in long-term maintenance. Endovascular treatments may provide a durable option for prolongation of patency in AVFs.

Methods

Retrospective observational study was done on 46 patients with AVF for hemodialysis in the Department of Diagnostic and Interventional Radiology for a period of 1 year from September 2020 to August 2021. The characters of dysfunctional fistulas and results of various interventional procedures were assessed for technical and clinical success rates. Short-term follow-up records of patients were assessed for post-intervention primary patency (PIPP) and post-intervention assisted primary patency (PIAPP) of various procedures.

Results

The most successful outcomes post intervention were seen in radio-cephalic fistulas formed more than 1 year ago with juxta-anastomotic narrowing. The overall technical success rate was 89.13% with a PIPP of 78.26% and a PIAPP of 82.60% at 3 months. PTA had better technical success rates (88.23%) as compared to dysfunctional segments with thrombosis that underwent angioplasty and thromboaspiration (84.2%). Central venous stenosis undergoing PTA and stenting had a 100% success rate. At 3 months follow-up, PIPP was better among the angioplasty plus thromboaspiration group (73.7%), while PIAPP rate was better in the angioplasty subgroup at 82.35%.

Conclusion

Endovascular intervention is the first-line treatment in dysfunctional AVFs attributable to the multitude of options available, all of which have comparable outcomes, high success rates, and notable short-term patency.

First Clinical Results of the Merit WRAPSODY™ Cell-Impermeable Endoprosthesis for Treatment of Access Circuit Stenosis in Haemodialysis Patients

PURPOSE

This prospective, observational first in human study evaluated the safety and effectiveness of WRAPSODY^TM Cell-impermeable Endoprosthesis (Merit Medical Systems, Inc.) in the treatment of arteriovenous fistula and arteriovenous graft access circuit stenosis.

MATERIALS AND METHODS

Investigators conducted a prospective analysis of 46 patients with access circuit stenosis from three centres. Treatment sites included the peripheral outflow veins (e.g. cephalic arch, basilic vein swing point; 16 fistula and 10 graft patients); the graft-vein anastomosis (9 patients); and the central veins (up to, but not including the SVC; 11 patients). Primary outcome measures included 30-day freedom from access circuit-related safety events and 30-day target lesion primary patency. Secondary outcome measures included procedural success; device- and procedure-related adverse events; target lesion primary patency; access circuit primary patency; and secondary patency. In-person follow-up was scheduled at 1, 3, 6, and 12 months. An independent data monitoring/clinical event committee adjudicated all reinterventions and device/procedure-relatedness for adverse events.

RESULTS

All initial procedures were successful. All but one patient was free from safety events through the first 30 days (97.8% (45/46)). This event was not device-related. Over the remainder of the study, one adverse event was adjudicated as possibly device-related. Six- and 12-month target lesion primary patency rates were 97.7% (42/43) and 84.6.% (33/39), respectively. Six- and 12-month access circuit primary patency rates were 84.4% (38/45) and 65.9% (29/44), respectively.

CONCLUSION

Results suggest that the study device is safe and effective for treatment of stenoses in the peripheral and central veins of arteriovenous access circuits.

LEVEL OF EVIDENCE

Level 2b, cohort study.

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.

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.

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.

Ultrasound-Guided Pharmacomechanical Thrombolysis and Angioplasty for Treatment of Acute Thrombotic Prosthetic Arteriovenous Access: 5-Year Experience with 154 Procedures in a Single Center

Pharmacomechanical thrombolysis (PMT) and percutaneous transluminal angioplasty (PTA) for the treatment of acute thrombotic prosthetic arteriovenous access (PAVA) are conventionally guided by radiography, which may cause radiation injury and requires the use of radiographic contrast media. The aim of the present study was to summarize our experience with ultrasound-guided PMT and PTA as an alternative to radiographic guidance. Between December 2012 and October 2016, 114 patients with acute thrombosis of PAVA were treated urgently with ultrasound-guided PMT and PTA to restore blood flow. The patients were followed up every 3 mo postoperatively. The 114 included patients underwent 154 episodes of ultrasound-guided PMT and PTA and were followed up for a mean of 20.7 ± 9.1 mo. The technical success rate was 91.6%, and the clinical success rate was 97.4%. Post-intervention-assisted primary patency rates at 3, 6, 12 and 24 mo were 90.8%, 78.8%, 66.3% and 50.9%, respectively. Post-intervention secondary patency rates at 3, 6, 12 and 24 months were 96.3%, 94.5%, 90.6% and 85.4%, respectively. PMT and PTA for the treatment of PAVA were performed successfully under the guidance of ultrasound with a success rate similar to that under radiographic guidance, thus avoiding radiation injury and contrast medium use, although close surveillance and timely intervention are imperative to ensure long-term patency.

Outcomes of Central Venoplasty in Haemodialysis Patients

Objective: To review the outcomes of central venoplasty in the treatment of symptomatic central vein stenosis in patients undergoing haemodialysis via an ipsilateral arteriovenous fistula (AVF).

Methods: Data were collected retrospectively, and included all the consecutive cases of central venoplasty between January 2008 and December 2015.

Results: A total of 132 central venoplasties in 76 patients were performed, with incidence of symptomatic central vein stenosis at 7.4%. Of the patients, 66% were male and the mean age was 61 years. The most frequent indication was decreased dialysis access flow rates (58%) and 52% of all the patients had symptoms of upper limb swelling. The patients who had previous ipsilateral tunneled internal jugular vein dialysis catheters made up 58% of the patients. The mean time from AVF creation to first central venoplasty was 24 months, and 74% of the cases required a second central venoplasty and the mean time to second venoplasty was 7 months. The overall post intervention assisted primary patency rate was 87%, 74%, 63%, and 42% at 6, 12, 18, and 24 months respectively. Statistically significant differences were found in primary assisted patency (p=0.025) and time to second procedure (p=0.039) comparing those with and without a history of ipsilateral tunneled dialysis catheter.

Conclusion: Central venoplasty is technically feasible with low procedural risk. The maintenance of the AVF patency usually requires multiple procedures at average interval of 7 months. Patients with a history of upper limb tunneled dialysis catheter ipsilateral to the side of central vein stenosis or AVF have a less favorable outcome compared to those without.

A pilot study on adjunctive use of parametric colour-coded digital subtraction angiography in endovascular interventions of haemodialysis access

Background

Two-dimensional digital subtraction angiography (DSA) is the gold standard for angiographic evaluation of dysfunctional haemodialysis access. We aim to investigate the utility of parametric colour coded DSA in providing hemodynamic analysis during haemodialysis access interventions.

Methods

We retrospectively studied 20 patients who underwent access intervention and applied parametric colour-coding on selected DSA acquisitions before and after percutaneous transluminal angioplasty (PTA). The difference in time to peak (dTTP) contrast enhancement and time attenuation curve (TAC) of pre- and post-stenotic regions of interest (ROIs) were obtained and compared after treatment.

Results

Improvements were seen in mean percent of stenosis after PTA (p < 0.0001) for all cases. Median dTTP improved from 0.52 (IQR 0.26, 0.8) to 0.25 (IQR 0, 0.26) seconds (p = 0.001). Median 50% contrast washout time improved from 0.77 (IQR 0.39, 1.17) to 0.42 (IQR 0.23, 0.59) seconds (p = 0.031). Significant correlation was seen for dTTP vs. percent of stenosis (r = 0.723, p = 0.043) pre-PTA and for change in dTTP vs. percent change in stenosis post-PTA (r = 0.786, p = 0.021) for inflow lesions. Such correlation was however not seen in outflow lesions.

Conclusions

Adjunctive use of parametric colour-coded DSA may provide potentially useful hemodynamic information during vascular access interventions. Larger prospective studies are needed to validate our findings.

A prospective randomized study of stent graft placement after balloon angioplasty versus balloon angioplasty alone for the treatment of hemodialysis patients with prosthetic graft outflow stenosis

BACKGROUND

Hemodialysis graft outflow stenosis is a significant complication occurring in hemodialysis patients with prosthetic grafts for vascular access. Balloon angioplasty remains the first-line endovascular treatment of this complication, although covered stent graft implantation after balloon angioplasty also appears to be an effective and promising treatment. The aim of this study was to evaluate the efficacy and durability of stent graft placement after balloon angioplasty in comparison to balloon angioplasty alone for the treatment of graft outflow stenosis in hemodialysis patients.

METHODS

We conducted a prospective randomized study of 98 patients with clinically significant dialysis graft outflow stenosis treated in the vascular surgery section of a tertiary medical center. The patients were randomized into two groups; 49 patients were treated with stent graft placement after balloon angioplasty, and 49 patients were treated with balloon angioplasty alone. All patients underwent angiography of the graft site at 3 and 6 months after intervention, and restenosis rates were compared between the two groups. In addition, the duration of postintervention primary patency in the two groups was recorded and analyzed.

RESULTS

The postintervention restenosis rate of the stent graft placement group was superior to that seen in the balloon angioplasty alone group (9% vs 69% at 3 months [P < .0001] and 29% vs 72% at 6 months [P < .0001]). The mean postintervention primary patency duration was 380.22 ± 28.54 days for the stent graft placement group and 151.08 ± 16.79 days for the balloon angioplasty alone group (P < .0001).

CONCLUSIONS

The use of stent grafts in hemodialysis patients with graft outflow stenosis yielded superior results compared with the results seen in hemodialysis patients treated with balloon angioplasty alone. Patients treated with stent grafts after balloon angioplasty had a lower restenosis rate and a longer duration of postintervention primary patency. The placement of a stent graft after balloon angioplasty appears to be an optimal therapeutic approach for the treatment of hemodialysis patients with graft outflow stenosis.

Preoperative management of arteriovenous fistula (AVF) for hemodialysis

Native arteriovenous fistula (AVF) is the favorite access for hemodialysis (HD). The National Kidney Foundation's Kidney Disease Outcomes Quality Initiative (KDOQI) recommends its creation in most patients with renal failure. Unfortunately, intensive efforts to promote native AVF in patients with marginal vessels have increased the rate of primary fistula failure. A non-functioning fistula prompts the use of central venous catheter (CVC) that, unlike AVF, has been associated with an increased risk of morbidity and mortality among patients receiving HD. We believe that successful and timely AVF placement relies on the development of a multidisciplinary integrated preoperative program divided into five stages: (i) management of patients with advanced chronic kidney disease (CKD), (ii) management of preoperative risk factors for AVF failure, (iii) planning of native AVF, (iv) assessment of patient eligibility and (v) preoperative vascular mapping. Focusing specifically on native AVF, we review scientific evidence regarding preoperative management of this vascular access in order to favor construction of long-term functioning fistula minimizing development of severe complications.