Association between heart failure and arteriovenous access patency in patients with end-stage renal disease on hemodialysis

BACKGROUND

Heart disease and chronic kidney disease are often comorbid conditions owing to shared risk factors, including diabetes and hypertension. However, the effect of congestive heart failure (CHF) on arteriovenous fistula (AVF) and AV graft (AVG) patency rates is poorly understood. We hypothesize preexisting HF may diminish blood flow to the developing AVF and worsen patency.

METHODS

We conducted a single-institution retrospective review of 412 patients with end-stage renal disease who underwent hemodialysis access creation from 2015 to 2021. Patients were stratified based on presence of preexisting CHF, defined as clinical symptoms plus evidence of reduced left ventricular ejection fraction (EF) (<50%) or diastolic dysfunction on preoperative echocardiography. Baseline demographics, preoperative measures of cardiac function, and dialysis access-related surgical history were collected. Kaplan-Meier time-to-event analyses were performed for primary patency, primary-assisted patency, and secondary patency using standard definitions for patency from the literature. We assessed differences in patency for patients with CHF vs patients without CHF, patients with a reduced vs a normal EF, and AVG vs AVF in patients with CHF.

RESULTS

We included 204 patients (50%) with preexisting CHF with confirmatory echocardiography. Patients with CHF were more likely to be male and have comorbidities including, diabetes, chronic obstructive pulmonary disease, hypertension, and a history of cerebrovascular accident. The groups were not significantly different in terms of prior fistula history (P = .99), body mass index (P = .74), or type of hemodialysis access created (P = .54). There was no statistically significant difference in primary patency, primary-assisted patency, or secondary patency over time in the CHF vs non-CHF group (log-rank P > .05 for all three patency measures). When stratified by preoperative left ventricular EF, patients with an EF of <50% had lower primary (38% vs 51% at 1 year), primary-assisted (76% vs 82% at 1 year), and secondary patency (86% vs 93% at 1 year) rates than those with a normal EF. Difference reached significance for secondary patency only (log-rank P = .029). AVG patency was compared against AVF patency within the CHF subgroup, with significantly lower primary-assisted (39% vs 87% at 1 year) and secondary (62% vs 95%) patency rates for AVG (P < .0001 for both).

CONCLUSIONS

In this 7-year experience of hemodialysis access creation, reduced EF is associated with lower secondary patency. Preoperative CHF (including HF with reduced EF and HF with preserved EF together) is not associated with significant differences in overall hemodialysis access patency rates over time, but patients with CHF who receive AVG have markedly worse patency than those who receive AVF. For patients with end-stage renal disease and CHF, the risks and benefits must be carefully weighed, particularly for those with low EF or lack of a suitable vein for fistula creation.

Intimal hyperplasia, saphenous vein graft disease, and clinical outcomes: Insights from the CTSN VEST randomized trial

BACKGROUND

Diffuse intimal hyperplasia and graft irregularity adversely affect the long-term patency of saphenous vein grafts (SVGs) and clinical outcomes of patients undergoing coronary artery bypass grafting (CABG). The VEST trial evaluated the efficacy of external graft support in limiting the development of intimal hyperplasia (IH) at 1 year postsurgery. In the present secondary analysis, we explored the associations between graft disease and IH and clinical events. We also examined risk factors for early graft occlusion.

METHODS

VEST is a within-patient randomized, multicenter trial that enrolled 224 patients with multivessel coronary disease undergoing CABG surgery, of whom 203 were evaluated by 1 year postsurgery. Intimal hyperplasia, lumen uniformity, graft stenosis, and graft perfusion were measured by intravascular ultrasound and angiography. Major cardiac and cerebrovascular events (MACCE; including death, myocardial infarction, stroke, and revascularization) were recorded over a median follow-up of 3 years.

RESULTS

Worse lumen uniformity, greater stenosis, and worse graft perfusion were associated with higher IH values and an increased incidence of clinical events. Consistent with previous findings, we identified endoscopic vein harvesting, female sex, and transit time flow measurement of pulsatility index and flow as risk factors for SVG occlusion during the first year postsurgery.

CONCLUSIONS

In this secondary analysis of the VEST trial, we observed an association between intimal hyperplasia area and clinical measures of SVG disease at 1 year postsurgery. More severe SVG disease and larger areas of IH were associated with a higher incidence of 3-year MACCE. Ongoing follow-up to 5 years will further elucidate the impact of SVG disease on long-term clinical outcomes of CABG.

Successful Removal of a Fractured Desilets-Hoffman Sheath in a Patient With a Loop Arteriovenous Graft: Balloon-Supported Retrieval Technique

INTRODUCTION

While a Desilets-Hoffman sheath rarely fractures, when it does, the presence of an intravenous foreign body can cause various complications.

CASE PRESENTATION

A 74-year-old woman receiving hemodialysis for end-stage renal disease via a left forearm arteriovenous graft (AVG) was referred to the interventional radiology department following thrombotic occlusion of the AVG. A corrective procedure was initiated, and the 7F Desilets-Hoffman sheath fractured after the purse-string suture. A .035-inch guidewire was passed through the fractured sheath, and a 3.0-mm x 60-mm balloon catheter was inflated, allowing for the successful removal of the sheath fragment without complications.

CONCLUSION

The fractured Desilets-Hoffman sheath was successfully removed in a patient with a loop arteriovenous graft using balloon-supported retrieval technique.

Use of Covered Stents in Cannulation Sites as a Last Option to Salvage Failing Vascular Access

PURPOSE

Controversy exists regarding the treatment of recurrent stenosis in vascular access at cannulation sites with a covered stent as repeated cannulation may damage the stent. The purpose of this study was to review covered stent placement at cannulation sites to salvage failing vascular access.

MATERIALS AND METHODS

A total of 11 patients were included for the purpose of this study. Eight patients (72.7%) received a covered stent due to recurrent stenosis, 2 (18.2%) due to an acute occlusion, and in 1 case (9.1%), the covered stent was used to repair a damaged polytetrafluoroethylene arteriovenous graft (PTFE AVG).

RESULTS

Primary patency after stent placement was 40.9% at 6 months, primary-assisted patency was 79.5% at 12 months, and secondary patency was 80% at 24 months. No significant problems were observed during the dialysis sessions after stent placement. The intervention rate per patient-year was not significantly different before or after covered stent placement, at 3.8 (IQR=9.5) interventions per year versus 2.5 (IQR=3.0) interventions per year (p=0.280).

CONCLUSION

In conclusion, treating failing vascular access with problems at cannulation sites with covered stents can be considered.

CLINICAL IMPACT

Treating vascular access stenosis at cannulation sites with covered stents can successfully prolong vascular access life.

The role of vacuum-assisted mechanical thrombectomy in the management of acutely thrombosed arteriovenous fistulas and grafts

PURPOSE

The purpose of this study is to evaluate the safety and efficacy of the mechanical thrombectomy with the Indigo System in the treatment of thrombosed arteriovenous fistulas and grafts.

METHODS

A retrospective search of endovascular procedures performed from November 2018 to June 2020 was conducted. Inclusion criteria were: acute arteriovenous fistula or graft thrombosis that underwent endovascular mechanical thrombectomy with Indigo System. The following information was collected from each case: sex, age, fistula modality, fistula location, treatment modality, and outcomes. Endpoints evaluated were: technical and clinical success rates; primary, assisted primary, and secondary patency rates; complication rates.

RESULTS

Twenty-six mechanical thrombectomy procedures for declotting of arteriovenous fistula thrombosis, using the Indigo System, were performed in 22 patients. Technical and clinical success was achieved in 23/26 cases (88%). Mean follow-up was 9 months (range 11-539 days). The 6-month primary, primary assisted, and secondary patency rates were 71%, 86%, 93% and the 12-month primary, primary assisted, and secondary patency rates were 71%, 72%, 80%, respectively. No technical or device-related complications were observed during thrombectomy, however two venous ruptures occurred on the angioplasty of the underlying stenosis.

CONCLUSION

In conclusion, vacuum-assisted thrombectomy of acutely thrombosed arteriovenous fistulas and grafts with Indigo System is safe and effective, providing good short term patency rates.

Rotational Mechanical Thrombectomy to Treat Iliac Limb Occlusion after Endovascular Aortic Aneurysm Repair: The Rotational Mechanical Thrombectomy Italian Study

PURPOSE

To assess the safety and effectiveness of a rotational mechanical atherothrombectomy device in patients with symptomatic iliac limb occlusion after abdominal endovascular aneurysm repair (EVAR).

MATERIALS AND METHODS

A retrospective analysis was conducted on patients who underwent rotational mechanical thrombectomy using the Rotarex S device for symptomatic acute, subacute, or chronic graft limb thrombosis at 5 vascular centers between 2017 and 2021. This study comprised 23 male patients with a mean age of 74.5 years (SD ± 7.2) at the time of the procedure. The clinical presentation of the patients varied, with 1 patient experiencing acute limb ischemia and 11 patients (47.8%) experiencing disabling intermittent claudication. The remaining patients developed chronic limb-threatening ischemia after iliac limb occlusion. Early outcomes included technical success, postprocedural complications, and periprocedural mortality. Follow-up evaluations encompassed primary patency, patient survival, freedom from reintervention, and the need for surgical conversion.

RESULTS

Technical success was achieved in all cases, with no occurrences of distal embolization during or after the procedure, and no periprocedural deaths were reported. Endograft relining was performed in 82.6% of patients to establish a new, nonthrombogenic surface within the graft. Over a median follow-up period of 8 months (interquartile range, 3-16 months), 2 patients experienced iliac limb reocclusion. No deaths or other reinterventions occurred during the observational follow-up period.

CONCLUSIONS

Rotational mechanical thrombectomy for iliac limb occlusion after EVAR appears to be both safe and effective. This technique may uncover intraluminal defects contributing to graft occlusion and enable their resolution within the same procedure.

Treatment of intragraft stenosis in hemodialysis grafts with Supera stents: A retrospective study

PURPOSE

To report the patency rates after implantation of an interwoven nitinol stent to salvage failing arteriovenous grafts (AVGs) caused by intragraft stenoses.

METHODS

Between May 2018 and May 2020, 21 Supera stents were placed in 20 patients (18 women; mean age: 79.9 years) who had a failing AVG due to repeat intragraft stenoses. Recurrent AVG dysfunction with same intragraft stenosis within 3 months after first time angioplasty was a criterion for stenting. Those with concurrent treatment for other lesions were excluded.

RESULTS

The technical success rate was 100%. Intragraft stenoses were treated at a median of 19.7 (interquartile range: 6-36) months after graft creation. Access circuit primary patency rates after stent placement were 84% and 35% at 6 and 12 months, respectively. Access circuit secondary patency rates were 100% at 6 and 12 months and 89% at 18 months. Only one patient presented with graft failure due to proximal drainage vein occlusion. The target lesion patency rates were 100% at 6 months and 75% at 12 months. The rate of reintervention for intragraft lesion was 0.15 procedures per year. Stent distortion did not occur under regular cannulation.

CONCLUSION

The interwoven nitinol stent is a promising treatment for failing AVGs with recurrent intragraft stenoses. The 1-year access circuit primary, secondary, and target lesion patency rates were acceptable, with a low reintervention rate. Stent fracture does not occur in areas of needle puncture.

A Prospective Multicenter Randomized Controlled Trial for Comparing Drug-Coated and Conventional Balloon Angioplasty in Venous Anastomotic Stenosis of Hemodialysis Arteriovenous Grafts

PURPOSE

To evaluate the efficacy and safety of drug-coated balloon angioplasty compared to conventional balloon angioplasty in the treatment of dysfunctional arteriovenous grafts.

MATERIALS AND METHODS

This prospective, multicenter, randomized clinical trial enrolled 190 patients with venous anastomotic stenosis in arteriovenous grafts at five participating hospitals. During pre-dilation, 4 patients dropped out due to ruptures requiring further treatment (n = 2) and residual stenosis of > 30% (n = 2). On successful pre-dilation with a 7 mm conventional balloon, patients were randomized to undergo either a 7 mm drug-coated balloon (n = 94) or conventional balloon angioplasty (n = 92). The primary out-come measure was target lesion primary patency at 3 and 6 months. The secondary out-come measures included target lesion primary patency at 12 months and access circuit primary patency at 6 and 12 months, clinical and technical success rates, and 12-month mortality differences between the groups.

RESULTS

The target lesion primary patency and access circuit patency rates at 3 and 6 months were significantly higher in drug-coated balloon angioplasty group as compared to conventional balloon angioplasty group. The technical and clinical success rates were 100% for both the groups. As a procedure-related complication, anastomotic site rupture occurred during pre-dilation in 4 cases. The number of deaths during the 12-month follow-up was one for each group. The number of early thrombotic events (at < 3 months) was significantly higher in the drug-coated balloon group (p = 0.002).

CONCLUSION

Drug-coated balloon angioplasty was more effective and safer for the treatment of dysfunctional arteriovenous grafts compared to conventional balloon angioplasty.

Sirolimus-coated balloon angioplasty in maintaining the patency of thrombosed arteriovenous graft: 1-year results of a prospective study

BACKGROUND

A prospective, pilot study was designed to test the feasibility of using sirolimus-coated balloon (SCB) to treat graft vein junction of thrombosed arteriovenous graft (AVG) following successful pharmacomechanical thrombectomy. The present report provides the 1-year results of this study.

METHODS

This is a 1-year follow-up of a single, prospective, single-arm study that was conducted from 2018 to 2019 in 20 patients who presented to a tertiary institution with thrombosed AVG. The recruited patients received SCB angioplasty at the graft-vein junction following successful endovascular thrombectomy of a thrombosed AVG. One year after recruitment, there were three deaths, one AVG revision, and one AVG explantation among the participants recruited. The outcomes of 15 subjects at 1-year following the index procedure obtained from electronic medical records were re-examined.

RESULTS

The 1-year access circuit primary patency rate was 40%, while assisted primary and secondary patency rates were 46.7% and 73.3%, respectively. A total of 16 interventions (4 angioplasties, 12 thrombectomies) were performed in 9 patients over the 12 months. Four AVGs were abandoned. The median number of interventions per patient was 1 (0-3) per year. Using Kaplan-Meier analysis, the mean estimated post-intervention access circuit primary patency was 230 (95% CI: 162-300) days, while access circuit assisted primary patency was 253 (95% CI: 187-320) days, and access circuit secondary patency was 292 (95% CI: 230-356) days. Sub-group analysis did not show a significant difference in the mean estimated primary patency between AVG with de novo and recurrent stenosis (245 days, 95% CI: 151-339 vs 210 days, 95% CI: 113-307; p = 0.29).

CONCLUSIONS

SCB may help sustain the patency of thrombosed AVG following successful thrombectomy.

An unusual spontaneous recanalization by multiple palmar arteriovenous connections of a chronically occluded radiocephalic hemodialysis fistula

Preservation of a vascular access is crucial in the management of hemodialysis patients. In this regard, percutaneous transluminal angioplasty (PTA) is an effective tool if performed after an adequate understanding of preliminary fistulograms. The present case showed a chronic dysfunction of a radial-cephalic arteriovenous fistula (AVF) due to arterial occlusion and partially relieved by the spontaneous development of multiple small arteriovenous connections in the palmar region of the hand. This dense network had been so far able to ensure a sufficient retrograde blood flow for an effective hemodialytic performance. The angioplasty of the post-anastomotic stenotic segment of the radial artery was effective in restoring this neoformed AVF patency.

A systematic review of right atrial bypass grafting in the management of central venous occlusive disease in patients undergoing hemodialysis

INTRODUCTION

Central venous occlusive disease (CVOD) is a complication that can occur in patients with end-stage renal disease who are receiving hemodialysis. When CVOD develops, patients often require multiple re-interventions to maintain their dialysis access. CVOD can be treated by various strategies such as balloon angioplasty, stenting, lower limb or extra-anatomical grafts, hybrid grafts or surgical bypasses such as right atrial (RA). In this systematic review, we aim to evaluate the indications, technical aspects, and outcomes after RA bypass grafting for the treatment of CVOD in hemodialysis patients.

METHODS

A systematic and comprehensive literature search was conducted using various electronic databases. We included articles that reported described and reported outcomes of RA bypass grafting for the treatment of CVOD in hemodialysis patients. A narrative review of the indications and technical aspects of RA bypass grafting was performed. We also pooled and reported the primary patency, secondary patency, postoperative complications, and 30-day mortality of RA bypass grafting.

RESULTS

A total of 21 studies with 55 patients who underwent RA bypass grafting were included in our systematic review. Follow-up period ranged from 0.5 to 84 months. The mean pooled primary patency and secondary patency of RA bypass grafting were 8.1 ± 4.9 and 21.7 ± 20.1 months, respectively. The incidence of early postoperative complications such as surgical site infection, bleeding, and access thrombosis was 0%, 4%, and 4%, respectively. The overall 30-day mortality was 4%.

CONCLUSIONS

This systematic review summarizes the patient characteristics, technical features and outcomes of RA bypass grafting in the treatment of hemodialysis-related CVOD. RA bypass grafting may be a viable last-resort option when less invasive or conventional treatment options have been exhausted.

Patency and Durability of Stent Grafts Placed in the Dialysis Circuit Cannulation Zone

PURPOSE

To investigate the safety, durability, and patency rates of stent grafts (SGs) placed in the cannulation zone of hemodialysis access circuits.

MATERIALS AND METHODS

From April 2020 to April 2023, all procedures with SGs placed in the cannulation zone were retrospectively analyzed. A total of 40 patients (25 men and 15 women) with SGs placed in the cannulation zone were included in the study. Mean age of the patients was 70 years. The Covera covered stent (BD, Franklin Lakes, New Jersey) was used in all cases. Of these, 26 were arteriovenous (AV) fistulae and 14 were AV grafts. SGs were placed for residual stenosis, perforation, aneurysm, and thrombosis. Follow-up outcomes were determined using follow-up angiographic images and included primary patency, primary-assisted patency, and secondary patency.

RESULTS

The primary patency of the target lesion was 89% (SD ± 5) and 74% (SD ± 8.4) at 6 and 12 months, respectively. The primary-assisted patency was 89% (SD ± 5.2) and 78% (SD ± 7.6) at 6 and 12 months, respectively. Secondary patency of the access circuit was 97% (SD ± 2.5) at both 6 and 12 months. Mean follow-up was 332 days (range, 28-661 days). All SGs were successfully cannulated for hemodialysis. No cases of stent fracture or stent infection were observed during follow-up.

CONCLUSIONS

SGs placed for cannulation zone pathologies can be safely cannulated for dialysis and have adequate short- and mid-term patency rates.

Double guidewire technique (DGT): Optimising endovascular revision of juxta-anastomotic stenosis in AV-fistulae: A retrospective analysis

BACKGROUND

Arteriovenous fistula (AVF) is the preferred angioaccess for haemodialysis but suffers from a high stenosis rate, juxta-anastomotic stenosis (JAS) being the most frequent. Percutaneous transluminal angioplasty (PTA) of JAS would have some advantage (such as mini-invasive and vein sparing treatment), but higher recurrence rate is observed as compared to surgery. We report results of juxta anastomotic stenosis PTA using the 'double guide technique' (DGT) as described by Turmel-Rodrigues, in a selected cohort from our Vascular Access Centre.

PATIENTS AND METHODS

From January to June 2018, 25 consecutive patients were treated by DGT. By means of retrograde access through the outflow vein by a 6 F introducer, two guide wires were navigated: one into proximal radial artery (GW1), the other into distal artery (GW2). GW2 was used to dilate juxta-anastomotic vein and anastomotic area with 6 mm high-pressure balloon, while by GW1 juxta-anastomotic artery was dilated with 4 mm semi-compliant balloon. Mean diameter of balloons were 6.7 and 4.1 mm for venous and arterial tract dilatation. Follow up was carried out up to 12 months. Prospectively collected data were analysed retrospectively.

RESULTS

One-year primary and secondary patency was 52% and 95% respectively. Recurrence rate was 0.56 procedure/pt/year. Mean access blood flow at 12 months was 830 ml/min.

CONCLUSION

Double Guidewire Technique is an effective and minimally invasive procedure. By avoiding under dilation of JAS the recurrence rate resulted quite satisfactorily in our population.

A Retrospective Evaluation of Intra-Prosthetic Thrombus Formation After Endovascular Aortic Repair in Cook Zenith Alpha and Medtronic Endurant II Patients

OBJECTIVE

To investigate the occurrence of limb graft occlusion (LGO) and intra-prosthetic thrombus (IPT) formation in Zenith Alpha and Endurant II stent graft limbs.

METHODS

A single centre retrospective study was conducted on patients treated with the Zenith Alpha and Endurant II stent grafts between 2017 and 2019. All post-operative computed tomography angiography images were re-investigated for thrombus formation. Demographic, aneurysm, and stent graft data were collected and compared. LGO was defined as complete occlusion or significant stenosis (≥ 50% lumen diameter reduction). Logistic regression on pro-thrombotic risk factors was conducted. Freedom from LGO and overall limb IPT were compared using Kaplan-Meier analyses.

RESULTS

Seventy-eight Zenith Alpha and eighty-six Endurant II patients were studied. The median follow up was 33 (IQR 25, 44) months for Zenith Alpha patients and 36 (IQR 22, 46) months for Endurant II patients (p = .53). LGO was seen in 15% (n = 12) of Zenith Alpha patients and 5% (n = 4) of Endurant II patients (p = .032), and freedom from LGO was significantly higher among Endurant II patients (p = .024). The Zenith Alpha stent graft was an independent risk factor for LGO (OR 3.9, 95% CI 1.1 - 13.4; p = .032). Among Zenith Alpha patients, limb flare compression within the main body gate was over represented in LGO patients (p = .011). There was no difference in freedom from overall limb IPT between the stent graft systems. For Endurant II limbs, IPT was significantly less common in the integrated ipsilateral limbs (without ETLW/ETEW stent graft limbs) (p = .044). Main endograft body IPT was correlated with overall limb IPT (p = .035).

CONCLUSION

LGO was significantly more common among Zenith Alpha than Endurant II patients. Zenith Alpha limbs was an independent risk factor for LGO. There was no difference between stent grafts in overall limb IPT formation.

Delamination and dissection of arteriovenous grafts: A multicenter report of four cases

Arteriovenous (AV) grafts are an alternative vascular access for chronic hemodialysis. AV graft failure is often due to stenosis of the feeding artery, graft, or draining vein. We report four cases of AV graft dysfunction and failure rarely caused by graft delamination and dissection. Two males and two females aged 47-67 years had been on chronic hemodialysis. Ultrasound examination detected graft delamination and dissection between 1 and 33 months after Acuseal AV graft implantation. Two cases were successfully treated with stenting and partial graft replacement, respectively. False lumen volume reduction by fluid withdrawal failed to salvage the delaminated graft in one of the patients. The delamination and dissection of another case spontaneously resolved 5 months later. Graft delamination and dissection should be considered as a possible cause for AV graft dysfunction and failure. Stenting and graft replacement may be recommended to treat AV graft dissection and delamination.

A Multicenter Analysis of Revision of Aneurysmal Dialysis Access Using Bovine Carotid Artery Conduit

BACKGROUND

Dialysis access complications and failure requiring revision are common. Understanding which methods of revision yield the optimal patency rates and lowest complications remain in evolution. Revision of native vessels is preferred, with revision using expanded polytetrafluoroethylene (ePTFE) graft as an alternative. Revision with Bovine Carotid Artery Graft (Artegraft) has historically been indicated when other options have been exhausted. While earlier studies demonstrated lower patency and higher infection rates compared to ePTFE, more recent studies have suggested otherwise. We describe our experience with patients who underwent arteriovenous access revision with Artegraft, and present this as a viable alternative.

METHODS

A multicenter analysis was conducted over 6 years of 25 patients with arteriovenous access complications requiring revision. Complications included aneurysmal degeneration, bleeding, recurrent thrombosis, and sclerotic outflow. Patients were grouped into 2 groups based on the complication. The first group included aneurysm-only complication and the second group included aneurysm and all other complications. All patients underwent revision of their arteriovenous fistula with excision of diseased segment of the arteriovenous fistula and interposition placement of Artegraft. All patients were followed long term and assessed for postop complications, patency, and any reintervention.

RESULTS

Of 25 patients, 13 were male and 12 female. Average age was 57 (range 27-83). Sixteen of the 25 patients had follow-up. Of the 16, 10 patients had primary patency (62.5%), 3 with primary-assisted patency (18.75%), and 3 with failure of grafts (18.75%). Ten of the 16 had at least 1 year or greater follow-up (5 with primary patency, 3 primary-assisted patency, and 2 with failure both of which failed after 1 year). Those that required intervention to maintain patency were from thrombosis requiring declot or anastomotic stenosis requiring angioplasty. None of the followed patients were found to have neither postoperative surgical site nor graft infections.

CONCLUSIONS

This case series supports that arteriovenous access revision with Artegraft is a viable option that has acceptable patency rates (81% overall functional patency rate at 1.5 years), with an observed 0% infection rate, and is comparable to ePTFE. With more recent studies suggesting Artegraft may have superior outcomes, further study and consideration should be given to using Artegraft as a conduit for arteriovenous fistula revision.

Feasibility of Percutaneous Ultrasound Guided Intervention with Direct Access in Failing Infrainguinal Vein Bypass Grafts

BACKGROUND

Patients with infrainguinal venous bypass grafts are at risk of graft stenosis leading to thrombosis and failure of the graft conduit. When primary assisted reintervention is needed, a common first choice of treatment is percutaneous angioplasty using fluoroscopy and digital subtraction angiography (DSA). We investigated whether percutaneous ultrasound-guided intervention (PUSGI) is feasible for such endovascular reinterventions.

METHODS

In this retrospective observational study (feasibility study), we included patients with ultrasound evidence of significant stenosis in below-the-knee vein grafts in the lower extremities. Inclusion period was 18 months. Reinterventions were disrupted by performing PUSGI in between traditional DSA. Perioperative success was defined as no sign of residual stenosis, stenosis at the access point in the vein, or need for further fluoroscopy guided intervention. Patient follow-up was conducted 6 weeks after the intervention. Patency of the procedure was defined as no disease recurrence or signs of ultrasonographic restenosis at follow-up.

RESULTS

PUSGI was performed in 17 patients referred for reintervention with imminent failing grafts (12 men, 5 women, age range 52-82 years). PUSGI alone was performed successfully in 10 out of 17 patients (59%). The remaining 7 patients underwent successful revascularization with PUSGI in combination with DSA-guided angioplasty. Periprocedural complications occurred in 4 patients. Two of 17 patients had occluded grafts at 6 weeks of follow-up. No PUSGI access site stenoses in grafts were observed.

CONCLUSIONS

Percutaneous ultrasound-guided reintervention in peripheral vein bypass disease is feasible for selected patients. The study provides insight to qualitative criteria of eligibility for PUSGI in such reinterventions with direct conduit access.

Outcome after early thrombotic occlusion of arteriovenous fistulas

OBJECTIVE

Arteriovenous fistulas (AVFs) are considered the first choice for venous access in end-stage renal disease patients, however, they are also known to have a high primary failure rate (early thrombosis and maturation failure). Of these, the outcome of thrombosed immature AVFs is not well known. This study aimed to investigate the outcome of AVFs with early thrombosis.

METHODS

Patients who underwent AVF creation from January 2009 to December 2019 at Seoul National University Hospital or Seoul Metropolitan Government - Seoul National University Boramae Medical Center were retrospectively reviewed. Patients who received salvage operations due to early thrombosis within 30 days after access creation were analyzed.

RESULTS

During the study period, a total of 45 patients (radiocephalic 26; brachiocephalic 19) developed early thrombosis and underwent salvage operations. The median age of patients was 61.0 (54.5-69.5) years, and 51.1% were male. The first salvage operation was performed on the median 1.0 (0.0-4.5) day after AVF creation. The most common cause for early thrombosis was venous stenosis (64.4%) and followed by poor arterial inflow (28.9%), especially in radiocephalic AVFs. About 20 AVFs were salvaged to maturation (46.5%). Post-salvage primary patency and secondary patency at 1 year was 72.6% and 100%. In a multivariate logistic regression, significant risk factors for maturation failures were minimum venous outflow diameter ⩽2.5 mm (OR, 4.433; 95% CI, 1.039-18.921; p = 0.044) and lower in patients with hypertension (OR, 0.064; 95% CI, 0.006-0.637; p = 0.019).

CONCLUSIONS

Thrombosed immature AVFs are associated with a high failure rate after salvage operation. However, if the salvage operation is successfully performed, it is associated with an acceptable 1-year outcome.

Non-contrast computed tomography findings for identification of chronically occluded coronary artery bypass grafts

BACKGROUND

Detecting occlusions of coronary artery bypass grafts using non-contrast computed tomography (CT) series is understudied and underestimated.

PURPOSE

To evaluate morphological findings for the diagnosis of chronic coronary artery bypass graft occlusion on non-contrast CT and investigate performance statistics for potential use cases.

MATERIAL AND METHODS

Seventy-three patients with coronary artery bypass grafts who had CT angiography of the chest (non-contrast and arterial phases) were retrospectively included. Two readers applied pre-set morphologic findings to assess the patency of a bypass graft on non-contrast series. These findings included vessel shape (linear-band like), collapsed lumen and surgical graft marker without a visible vessel. Performance was tested using the simultaneously acquired arterial phase series as the ground truth.

RESULTS

The per-patient diagnostic accuracy for occlusion was 0.890 (95% confidence interval = 0.795-0.951). Venous grafts overall had an 88% accuracy. None of the left internal mammary artery to left anterior descending artery arterial graft occlusions were detected. The negative likelihood ratio for an occluded graft that is truly patent was 0.121, demonstrating a true post-test probability of 97% for identifying a patent graft as truly patent given a prevalence of 20% occlusion at a median 8.4 years post-surgery. Neither years post-surgery, nor number of vessels was associated with a significant decrease in reader accuracy.

CONCLUSION

Evaluation of coronary bypass grafts for chronic occlusion on non-contrast CT based off vessel morphology is feasible and accurate for venous grafts. Potential use cases include low-intermediate risk patients with chest pain or shortness of breath for whom non-contrast CT was ordered, or administration of iodine-based contrast is contraindicated.

Venous Hypertension Improved by a Viabahn Stent Graft Blocking Regurgitation to the Periphery of the Basilic Vein in an Elderly Patient Undergoing Hemodialysis: A Case Report

Although necessary for hemodialysis (HD), arteriovenous grafts (AVG) frequently cause complications. Stenosis resulting in venous hypertension is a concern for physicians. Herein, we describe how venous hypertension was improved by using a Viabahn stent graft in an elderly HD patient. An 86-year-old woman started maintenance HD with a left-arm AVG. Two years later, she was referred to our hospital for treatment of juxta-graft-venous junction (GVJ) stenosis. Because of recurrence of stenosis at the juxta-GVJ, she underwent four percutaneous transluminal angioplasty (PTA) procedures during a period of 9 months. One month after the most recent PTA, the patient had redness, swelling, and pain in her left forearm. Venous hypertension was diagnosed on the basis of angiography findings showing regurgitation to the periphery of the basilic vein and juxta-GVJ stenosis. The stenosed juxta-GVJ was adequately expanded with a 7-mm balloon, and a 7-mm stent graft was inserted into the stenosis site. After successful treatment, there was no regurgitation to the periphery of the basilic vein and no symptoms. This complication should be considered when an AVG is created, because cutting off peripheral veins might prevent venous hypertension. Clinicians should perform regular postoperative monitoring.

Dialysis Access Maintenance: Plain Balloon Angioplasty

Plain balloon angioplasty remains the first-line treatment for dialysis access stenosis. This chapter reviews the outcomes of plain balloon angioplasty from cohort studies and comparative studies. Angioplasty outcomes are more favourable in arteriovenous fistulae (AVF) compared to arteriovenous grafts (AVG) with primary patency at 6 months ranging from 42-63% compared to 27-61%, respectively, and improved for forearm fistulae compared with upper arm fistulae. Higher pressures are required to treat stenoses in AVFs compared to AVGs. Outcomes are worse in more severe stenoses, increased patient age, previous interventions and fistulae that develop early stenoses. Major complication rates following angioplasty in dialysis access are between 3 and 5%. Repeat treatments and the use of adjuncts such as drug-coated balloons and stents can prolong the patency of dialysis access. Level of Evidence No level of evidence (Review paper).

The Role of Drug-Coated Balloon in Haemodialysis Arteriovenous Fistula Stenosis Management

Arteriovenous fistula (AVF) stenosis is a common problem leading to dialysis access dysfunction. The conventional balloon (CB) is the most commonly used device during angioplasty but suffers from poor durability of results due to neointimal hyperplasia-mediated recurrence. The drug-coated balloon (DCB) is an adjunct to balloon angioplasty that reduces neointimal hyperplasia, thereby improving post-angioplasty patency. Despite the heterogeneity of DCB clinical trials to date, the evidence suggests that DCBs of different brands are not necessarily equal, and that patient selection, adequate lesion preparation and proper DCB procedural technique are important to realize the benefit of DCB angioplasty.

Prospective, randomized, multicenter clinical study comparing a self-expanding covered stent to percutaneous transluminal angioplasty for treatment of upper extremity hemodialysis arteriovenous fistula stenosis

Use of a covered stent after percutaneous transluminal angioplasty (PTA) was compared to PTA alone for treatment of upper extremity hemodialysis patients with arteriovenous fistula (AVF) stenoses. Patients with AVF stenosis of 50% or more and evidence of AVF dysfunction underwent treatment with PTA followed by randomization of 142 patients to include a covered stent or 138 patients with PTA alone. Primary outcomes were 30-day safety, powered for noninferiority, and six-month target lesion primary patency (TLPP), powered to test whether TLPP after covered-stent placement was superior to PTA alone. Twelve-month TLPP and six-month access circuit primary patency (ACPP) were also hypothesis tested while additional clinical outcomes were observed through two years. Safety was significantly non-inferior while six- and 12-month TLPP were each superior for the covered stent group compared to PTA alone (six months: 78.7% versus 55.8%; 12 months: 47.9% versus 21.2%, respectively). ACPP was not statistically different between groups at six-months. Observed differences at 24 months favored the covered-stent group: 28.4% better TLPP, fewer target-lesion reinterventions (1.6 ± 1.6 versus 2.8 ± 2.0), and a longer mean time between target-lesion reinterventions (380.4 ± 249.5 versus 217.6 ± 158.4 days). Thus, our multicenter, prospective, randomized study of a covered stent used to treat AVF stenosis demonstrated noninferior safety with better TLPP and fewer target-lesion reinterventions than PTA alone through 24 months.

Use of Surfacer, an inside-out device, in tandem with HeRO graft for creation of vascular access: Case report of three patients with 18-months follow up

The Surfacer Inside-Out Access Catheter System (Surfacer) is a novel approach to restore access in total central vein occlusion (TCVO). We report a series of three cases, with mean 18-months follow up, in our institution where this technique was safely and effectively used in tandem with Hemodialysis Reliable Outflow (HeRO) graft for creation of upper limb vascular access in patients with TCVO. Although there have been reports describing the simultaneous combination of Surfacer and HeRO graft, to our knowledge, this is the first time where the outcomes with 18-months mean follow-up are reported. All three patients had failed prior conventional attempts at TCVO crossing and had exhausted most conventional upper limb vascular access methods. The above technique yielded a 100% technical success rate with mean operative time of 140 min. Cannulation rate was 100% with all undergoing successful early cannulation by post-operative day 3. Mean primary patency of 199 days was achieved. Average intervention rate of 1.2 a year was required to maintain patency. The Surfacer device used together with HeRO graft is a feasible technique to avoid femoral catheter in patients where conventional attempts to cross the TCVO have failed.

Upper thigh loop prosthetic arterio-venous grafts (AVG) for dialysis access: An Indian perspective

INTRODUCTION

Hemodialysis forms the most common replacement therapy for majority of Indians suffering from chronic kidney disease (CKD). Multiple access failure and central vein stenosis has become commonplace in Indian dialysis access patients and there is a burgeoning need for more advanced hemodialysis (HD) access options. Upper thigh arterio-venous grafts (AVG) are seldom inserted due to fear of infection and limb ischemia.

MATERIALS AND METHODS

This is a single institutional, retrospective, descriptive case study of consecutive patients who underwent upper thigh prosthetic AVG over a period of 7 years. All these patients had exhausted options of upper limb access and or had central vein stenosis. AVG from the proximal superficial femoral artery (SFA) to the proximal great saphenous vein (GSV) in a loop configuration using polytetrafluoroethylene (PTFE) was carried out in the upper thigh.

RESULTS

A total of 24 patients had undergone upper thigh loop AVG. Their age varied from 24 to 77 years. The median follow-up period was 3 years. Five of these grafts developed infection (21%) which led to primary failure. A primary patency of 71% (17/24 patients) was achieved at 1 year. Thrombosis developed at a mean of 16.7 months after the primary procedure. Adjunctive procedures such as thrombectomy, segmental replacement of graft, patch angioplasty, balloon angioplasty, and stenting were required in 75% of patients to achieve a secondary patency of 86% at 1 year. Three grafts were explanted without limb loss.

CONCLUSION

Upper thigh loop AVG forms a reliable alternate dialysis access option for patients with failed upper limb access sites or central vein occlusion. Adjunctive procedures are key to maintaining patency in these grafts. Good secondary patency is achievable, and the infection rates are similar to arm AVG. Close follow-up and timely intervention are key to long term dialysis through these grafts.

The management of dialysis access thrombosis during the COVID-19 pandemic

BACKGROUND

Maintaining patent access is essential for haemodialysis dependent end stage renal failure patients. The COVID-19 pandemic has significantly affected surgical and interventional radiology services worldwide. We aimed to review the impact COVID-19 has caused to the management of acute dialysis access thrombosis.

METHODS

We conducted a single centre retrospective review of outcomes of patients with arteriovenous fistula and arteriovenous graft thrombosis between March and May 2020, which coincided with the first peak of the COVID-19 pandemic in London, and a similar period in the previous year, March-May 2019. Outcomes in both cohorts of patients were compared, including attempts at salvage, salvage success, 1-month patency rates after salvage and subsequent surgery on the same access. We also analysed the use of tunnelled haemodialysis lines (THL), either due to failed salvage attempts or when salvage was not attempted.

RESULTS

There was a similar incidence of access thrombosis in both periods (26 cases in 2019, 38 in 2020). There were 601 patients dialysing via an arteriovenous fistula or graft in 2019, and 568 patients in 2020. Access salvage, when attempted, had similar success rates and 1-month patency (salvage success 74% vs 80%, p = 0.39; 1-month patency 55% vs 62%, p = 0.69). The proportion of patients where access salvage was not attempted and a THL inserted was significantly higher in 2020 compared to 2019 (32% vs 4%, p = 0.007). There were more patients who subsequently had surgery to salvage or revise the same access in 2019 compared to 2020 (62% vs 13%, p < 0.001).

CONCLUSIONS

During the peak of the COVID-19 pandemic, there were fewer attempts at access salvage. This was a conscious decision due to increased pressure on the healthcare system, access to emergency interventional radiology or operative theatres and the perceived risk/benefit ratio of access salvage. The long-term effects of this change in practice remain unknown.

Antecubital perforating vein stent-grafting for radiocephalic arteriovenous fistula recovery: A case report

Stent-grafts have been increasingly used in hemodialysis arteriovenous accesses, particularly in recurrent stenosis or in cases of vein rupture after percutaneous transluminal angioplasty (PTA). Although they limit neointimal hyperplasia, stenosis development at stent edges remains a concern. Despite their advantages, they are seldom used on the forearm veins due to fracture risk associated with elbow motion and the potential to limit cannulation sites. This report presents a novel application of stent-grafts in salvaging a radio-cephalic arteriovenous fistula in an 84-year-old male to treat a single outflow path at the elbow through a stenosed antecubital perforating vein, after failed PTA. The vascular access remained patent 18 months after the procedure, with no need for additional treatments at this target lesion, even though a PTA was required for juxta-anastomotic stenosis. This report highlights a possible further use of covered stents in arteriovenous vascular accesses.

Dialysis access graft occlusion with contrast and ultrasound guided thrombin injection for intractable arm edema and pseudoaneurysm

We present the case of a patient with a brachio-basilic graft forearm loop with intractable edema and thrombosed central veins. She showed up with an important edema after some effort and a previously thrombosed pseudoaneurysm with significant growth. She refused angioplasty treatment for central veins, the graft had not been used for dialysis during the last year, so that arteriovenous graft (AVG) ligation was considered. Due to local conditions thrombin percutaneous embolization was performed to avoid possible complications of a conventional surgery approach. AVG occlusion was done in 10 min by fluoroscopy and ultrasound guidance. In 24 h the patient was significantly better and after 1 week she had no edema at all. There were no complications and no recanalization was observed after 3 months. Percutaneous thrombin embolization is a safe and effective technique for AVG occlusion in case of intractable arm edema with central vein thrombosis, and most likely to be considered in other situations where arteriovenous graft or fistula ligature is needed.

Importance of Flow Waveform and Flow Volume as Prognostic Indicators for the Patency of Infra-Inguinal Autologous Vein Bypass

OBJECTIVE

To investigate the association of the intra-operative flow waveform and the flow volume with graft prognosis of the infra-inguinal vein bypass.

METHODS

This was a retrospective study of intra-operative flowmetry performed for infra-inguinal autologous vein bypass between 2011 and 2020. Flow waveforms were classified as type 0 - IV according to the Kyushu University (KU) classification. The patients (n = 340) were divided into three groups based on the flow waveform predicting the graft patency: type 0/I (long patency), type II (no early occlusion but late occlusion possible), and type III/IV (early occlusion). The graft occlusion rates of popliteal artery bypass (PAB) and infrapopliteal artery bypass (IPAB) within 30 days of surgery were compared between type 0/I + II and type III/IV groups, while the midterm graft patency rates were compared between type 0/I and type II groups. Additionally, a multivariate analysis was performed to identify independent risk factors for early and late graft occlusion.

RESULTS

The early graft occlusion rates of type 0/I + II and type III/IV groups were 3.9% and 0%, respectively, (p = 1.0) for PAB, and 5.3% and 46.2%, respectively, (p < .001) for IPAB. The two year primary patency rates of type 0/I and type II groups were 91% and 75%, respectively, (p = .030) for PAB, and 58% and 63%, respectively, (p = .72) for IPAB. Independent risk factors for early occlusion were none in PAB and flow waveform (type IV) in IPAB. Independent risk factors for patency loss in PAB were flow waveform (type II), end stage renal disease, and dual antiplatelet use, and those in IPAB were older age, women, lower flow volume, and iterative bypass.

CONCLUSION

Intra-operative flowmetry is useful for predicting the graft prognosis in infra-inguinal vein bypass and this is dependent on the distal target artery.

Evaluating national guideline concordance of recurrent interventions after radiocephalic arteriovenous fistula creation

OBJECTIVE

Radiocephalic arteriovenous fistulas have been historically perceived as requiring multiple follow-up procedural interventions to achieve maturation and maintain patency. Recent clinical practice guidelines from the National Kidney Foundation's Kidney Disease Outcomes Quality Initiative (KDOQI) emphasize a patient-centered hemodialysis access strategy with new maximum targets for intervention rates, potentially conflicting with concomitant recommendations to prioritize autogenous forearm hemodialysis access creation. The present descriptive study seeks to assess whether radiocephalic fistulas can meet the KDOQI guideline benchmarks for interventions following access creation, and to elucidate clinical and anatomic characteristics associated with the timing and frequency of interventions following radiocephalic arteriovenous fistula creation.

METHODS

Prospective patient-level data from the multicenter PATENCY-1 and PATENCY-2 randomized trials, which enrolled patients undergoing new radiocephalic arteriovenous fistula creation, was analyzed (ClinicalTrials.govNCT02110901 and NCT02414841). The primary outcome was the rate of interventions at 1 year postoperatively. Incidence rates were calculated, and time to surgical or endovascular intervention following fistula creation was modeled using recurrent event extensions of the Cox proportional hazards model. Confidence intervals at the 95% level were calculated using nonparametric bootstrapping.

RESULTS

The cohort consisted of 914 patients; mean age was 57 years (standard deviation, 13 years), and 22% were female. Median follow-up was 707 days (interquartile range, 447-1066 days). The incidence of interventions per person-year was 1.04 (95% confidence interval [CI], 0.95-1.13) overall; 1.10 (95% CI, 0.98-1.21) before fistula use, and 0.96 (95% CI, 0.82-1.11) after fistula use. The most common interventions overall were balloon angioplasty (54.9% of all interventions), venous side-branch ligation (16.4%), and open revisions (eg, proximalization from snuffbox to wrist, 16.4%). The locations requiring balloon angioplasty included the juxta-anastomotic segment (51.7% of angioplasties), the outflow vein (29.2%), the inflow artery (14.8%), the central veins (3.8%), and the cephalic arch (0.5%). Common indications were to restore or maintain patency (75.6% of all interventions), assist maturation (14.9%), improve depth (4.4%), or improve augmentation (3.0%). In the multivariable regression analysis, female sex (adjusted hazard ratio [HR], 1.21; 95% CI, 1.05-1.45), diabetes (HR, 1.21; 95% CI, 1.01-1.46), and intraoperative vein diameter <3.0 mm (vs ≥4.0 mm: HR, 1.33; 95% CI, 1.02-1.66) were associated with earlier and more frequent interventions. Patients not on hemodialysis at the time of fistula creation underwent less frequent interventions (HR, 0.69; 95% CI, 0.59-0.81).

CONCLUSIONS

Patients with radiocephalic arteriovenous fistulas can expect to undergo one intervention, on average, in the first year after creation, which aligns with current KDOQI guidelines. Patients already requiring hemodialysis, female patients, patients with diabetes, and patients with intraoperative vein diameters <3.0 mm were at increased risk for repeated intervention. No subgroup exceeded guideline-suggested maximum thresholds for recurrent interventions. Overall, the results demonstrate that creation of radiocephalic arteriovenous fistula remains a guideline-concordant strategy when part of an end-stage kidney disease life-plan in appropriately selected patients.

Role of Antiplatelet Therapy in Hemodialysis Arteriovenous Graft Secondary Patency Following Successful Percutaneous Thrombectomy

PURPOSE

The purpose of this study was to elicit the relationship of antiplatelet therapy (AP) in maintaining arteriovenous graft (AVG) patency after successful percutaneous pharmacomechanical thrombectomy ("declot").

MATERIALS AND METHODS

This was an institutional review board-approved retrospective review of AVG declot procedures between July 2019 and August 2020. AVG characteristics, bleeding complications, anticoagulation and antiplatelet medication regimens, and thrombosis free survival were evaluated. Recurrent time-to-event analysis was performed using a Prentice-Williams-Peterson Gap time model was performed to evaluate AVG thrombosis free survival.

RESULTS

A total of 109 declots were technically successful and performed in 63 individual patients. The majority of procedures were performed in upper arm grafts (71%, n = 45). Dual antiplatelet (DAPT) was prescribed after 52 declots (48%), single antiplatelet was prescribed after 36 declots (33%), and anticoagulation was prescribed after 31 declots (28%). Median thrombosis free survival was 37 days (range 1-412 days) in the no antiplatelet group, 84 days (range 1-427 days) in the single antiplatelet group, and 93 days (range 3-407 days) in the DAPT group. Anti-platelet medications trended towards protective of AVG thrombosis in multivariate analysis (hazard ratio 0.84, 95% confidence interval 0.60-1.19); however, this did not reach statistical significance (P = 0.33). A total of 4 major and 5 minor bleeding events occurred.

CONCLUSION

The results of this study support further evaluation of AP therapy in preventing secondary rethrombosis of dialysis AVG.

Comparing Patency Rates of Arteriovenous Dialysis Access following Percutaneous Thrombectomy Using Various Catheter Directed Therapies

BACKGROUND

Arteriovenous fistulas often require frequent interventions to maintain patency for hemodialysis. Interventions may include open or percutaneous thrombectomy with additional targeted interventions as indicated. We evaluated the primary and cumulative functional patency rates following three unique approaches to percutaneous thrombectomy of thrombosed dialysis access.

METHODS

A retrospective review of 236 unique patients who presented with thrombosed hemodialysis access was analyzed over a period of 4 years from 2016 to 2020. We analyzed a total of 413 procedures that utilized 3 separate percutaneous thrombectomy devices to assist with restoring patency. The Indigo System CAT-D Aspiration Thrombectomy Catheter (Penumbra; Alameda, CA), the Arrow-Trerotola Rotational Thrombectomy System (Teleflex; Wayne, PA) and the Angiojet Rheolytic Thrombectomy Catheter (Boston Scientific, Marlborough, MA) devices were compared for primary and cumulative functional patency. Primary patency was defined as time from percutaneous thrombectomy to next intervention (Angioplasty, stenting, and repeat thrombectomy). Cumulative functional patency was defined as time from percutaneous thrombectomy to time of access abandonment. Medical record chart review was utilized to determine patency rates.

RESULTS

A total of 413 percutaneous thrombectomy procedures were performed. Of the procedures performed, 98 utilized Angiojet, 103 utilized Trerotola, and 212 used Penumbra. The mean primary patency rates in (days) for the devices were as follows: Angiojet (194), Trerotola (204), and Penumbra (107). The mean cumulative functional patency rates (in days) for the devices were as follows: rheolytic thrombectomy (450 days), aspiration thrombectomy (292 days), and rotational thrombectomy (475 days). Angiojet versus Penumbra and Trerotola versus Penumbra both showed diminished patency rates when using the Penumbra catheter that were statistically significant (P < 0.05).

CONCLUSIONS

All percutaneous thrombectomy approaches do not result in the same primary or cumulative functional patency rates. Approaches with Trerotola and Angiojet resulted in improved primary and cumulative functional patency rates compared to those using Penumbra.

The role of stents in hemodialysis vascular access

Vascular access is the Achilles' heel of dialysis therapy among patient with end stage kidney disease. The development of neointimal hyperplasia and subsequent stenosis is common in vascular access and is associated with significant morbidity. Percutaneous transluminal angioplasty using balloon inflation was the standard therapy of these lesions. However, the balloon-based approaches were associated with poor vascular access patency rate necessitating new inventions. It is within this context that different types of stents were developed in order to improve the overall dialysis vascular access functionality. In this article, we review the available literature regarding the use of stents in treating dialysis vascular access stenotic lesions. Further, we review the major clinical trials of stent use in different anatomic locations and in different clinical scenarios.

Aneurysmal degeneration in the Omniflow II biosynthetic vascular graft

Despite advances in endovascular treatments, femoropopliteal bypass is still the best option for the treatment of lower-extremity occlusive artery disease. Omniflow II biosynthetic vascular grafts are often chosen as bypass grafts when autologous vein grafting is not possible. A negative feature of this graft is the tendency towards late biodegeneration with possible formation of graft aneurysms. In this case report, we present a thrombosed non-anastomotic biosynthetic graft aneurysm, which caused only a pulsatile mass in the inguinal region, in a 62-year-old male patient who had undergone a femoropopliteal bypass operation three years earlier. Aneurysm formation in vascular grafts is multifactorial and can cause life-threatening consequences. Therefore, all patients with biosynthetic vascular grafts should remain under lifetime surveillance with duplex ultrasound for aneurysmal graft degeneration and graft thrombosis.

A Single-Center Experience with Forearm Arteriovenous Loop Grafts for Hemodialysis

BACKGROUND

Autogenous arteriovenous fistula (AVF) remains the standard of hemodialysis (HD) access; however, it cannot be reasonably obtained in all patients. For patients with contraindications to AVFs, prosthetic arteriovenous graft (AVG) remains an alternative. AVGs are plagued by high failure rates; however, there is a paucity of literature examining this. This study aims to examine a single-center review of outcomes of forearm loop AVGs in patients requiring HD access.

METHODS

A single institution, retrospective chart review was completed from 2012 to 2019, including demographics, end-stage renal disease etiology, brachial vessel diameters, and comorbidities. Logistic regression and Cox proportional hazard models were evaluated. Outcomes were defined as primary patency (time elapsed from graft creation until it was utilized as the patient's primary access), primary-assisted patency (time from primary access to intervention to maintain patency), and functional patency (time from graft placement until graft failure). Additionally, multinomial regression models were used to evaluate associations with categorical number of required interventions.

RESULTS

Ninety-eight patients [mean age 61.8 (13.9) years, 42.9% female] were identified as having brachial artery to brachial vein AVG creation during the study period, of which 75% achieved primary patency. Primary-assisted patency was 0.36 [standard error (SE) 0.07] at 6 months and 0.12 (SE 0.05) at 1 year. Functional patency was 0.75 (SE 0.07) at 6 months and 0.43 (SE 0.09) at 1 year. No association between preoperative vessel diameters and primary-assisted or functional patency was observed. Interestingly, there was a significant negative association between previous ipsilateral access and achievement of primary patency with a 60% decrease in odds of achieving primary patency in patients with previous ipsilateral access [odds ratio 0.4, 95% confidence interval (CI) 0.1-0.9, P = 0.03]. There was also noted to be a significant association between the presence of an ipsilateral catheter and increased risk of subsequent abandonment of the AVG (hazard ratio 2.6, 95% CI 1.1-5.8, P = 0.02).

CONCLUSIONS

Prosthetic forearm loop AVGs remain hindered in their utility as they show high rates of graft failure within a year of creation. A significant patient-specific factor leading to this was not clearly demonstrated. As guidelines change regarding the nature of dialysis access for patients on HD, these results draw into question the utility of prosthetic forearm loop grafts in patients requiring long-term HD access.

Drug-Eluting Stents are Associated with Superior Mid-Term Outcomes for the Treatment of Infrainguinal Bypass Graft Stenoses

BACKGROUND

We previously demonstrated that everolimus drug-eluting stents (eDES) have reasonable short-term patency for the treatment of infrainguinal bypass stenoses. The aim of this study is to compare mid-term outcomes of eDES, plain balloon angioplasty (PTA), percutaneous cutting balloon (PCB), and drug-coated balloon (DCB) interventions for failing infrainguinal bypasses.

METHODS

We conducted a retrospective review of patients with infrainguinal bypass stenoses treated by endovascular intervention (August 2010-August 2021). The primary outcome was primary patency (PP). Secondary outcomes were primary-assisted patency (PAP), secondary patency (SP), limb salvage (LS), and mortality. Outcomes were compared by treatment using Kaplan-Meier curves with log-rank tests and Cox proportional hazards models adjusting for baseline differences between groups.

RESULTS

Seventy-two consecutive patients with 152 discrete infrainguinal bypass graft stenoses were identified. Mean age was 65.1 ± 10.6 years, 55.6% were male, and 48.6% were Black. In total, 81.9% of patients were originally treated for chronic limb-threatening ischemia, and 57.2% of distal anastomoses were to tibial or pedal targets. Of 152 lesions, 44.1% (n = 67) were treated with PTA, 17.8% (n = 27) with PCB, 20.4% (n = 31) with DCB, and 17.8% (n = 27) with eDES. Median follow-up was 28.5 months (interquartile range 11.5-51.9). There was no difference in bypass configuration, conduit choice, or stenosis location (proximal anastomosis, mid-bypass, distal anastomosis) between groups. At 24 months postintervention, PP was significantly better for eDES (72.9%, 95% confidence interval [CI] 49.8-85.6), followed by PCB (55.9%, 95% CI 34.2-72.9), PTA (34.4%, 95% CI 21.7-47.4), and DCB (33.6%, 95% CI 14.5-53.9) (P = 0.03). PAP, LS, and mortality did not significantly differ between modalities (P > 0.05). After risk adjustment, eDES was associated with the lowest risk of PP loss (hazard ratio versus PTA 0.15, 95% CI 0.05-0.47).

CONCLUSIONS

eDES is associated with superior 24-month patency rates compared to other endovascular technologies, and should be considered a primary therapy modality for the treatment of infrainguinal bypass graft stenoses.

Autogenous Vascular Access in American Indians

BACKGROUND

American Indians (AI) or Alaska Natives, or in combination with another race, comprised 6.8 million individuals in 2010 and the population is expected to exceed 10 million in the current census. Diabetes is more common in AIs than in other races in the United States and is responsible for 69% of new onset end stage renal disease in AI patients. The incidence of obesity is also higher among AIs. As both diabetes and obesity make creating a successful autogenous vascular access more challenging, we reviewed our experience creating arteriovenous fistulas in AI patients.

METHODS

Our vascular access database was reviewed for consecutive new AI patients undergoing creation of a hemodialysis vascular access during a 10-year period. Each patient underwent ultrasound vessel mapping by the operating surgeon in addition to history and physical examination. The goal for initial cannulation was 4-6 weeks after access creation. Minimal AVF flow volume for cannulation was 500 mL/min with an outflow vein diameter of 6 mm.

RESULTS

235 consecutive new AI patients were identified. All patients had an autogenous access constructed. The median age was 56 years (range, 15-89 years). Diabetes was present in 85% and 42% were female. Obesity was noted in 27% of the patients and 37% had previous vascular access operations. Primary patency at 12 and 24 months was 62% and 46%, respectively. Cumulative patency at 12 and 24 months was 96% and 94%, respectively. Female gender and previous access operations were associated with lower primary (P = 0.002 and 0.02, respectively) and cumulative patency (P = 0.01 and 0.04, respectively). Obesity was associated with lower cumulative access patency (P = 0.02). Overall, 74% of the access operations used the radial or ulnar artery for AVF inflow. Distal radial artery inflow AVFs were associated with longer patient survival (P = 0.01) and individuals with proximal radial inflow had longer survival when compared to brachial artery AVFs. Previous access operations were associated with shorter patient survival (P = 0.04).

CONCLUSIONS

Safe and functional arteriovenous fistulas can be created for American Indians despite a higher prevalence of vascular access risk factors such as diabetes and obesity.

Poor runoff and distal coverage below the knee are associated with poor long-term outcomes following endovascular popliteal aneurysm repair

OBJECTIVE

Reports of good short-term outcomes for endovascular repair of popliteal artery aneurysms have led to an increased use of the technique. However, data are lacking on long-term limb-related outcomes and factors associated with the failure of endovascular repair.

METHODS

All patients who underwent endovascular popliteal aneurysm repair (EPAR) at a single institution from January 2006 to December 2018 were included in the study. Demographics, indications, anatomic and operative details, and outcomes were reviewed. Long-term patency, major adverse limb event-free survival (MALE-FS) and graft loss/occlusion were analyzed with multivariable cox regression analysis and Kaplan-Meier curves.

RESULTS

We included 117 limbs from 101 patients with a mean follow-up of 55.6 months (range, 0.43-158 months). The average age was 73 ± 9.3 years. Thirty-two patients (29.1%) were symptomatic (claudication, rest pain, tissue loss, or rupture). The stent grafts crossed the knee joint in 91.4% of cases. In all, 36.8% of procedures used one stent graft, 41.0% used two stent grafts, and 22.2% of procedures used more than two stent grafts. The median arterial length covered was 100 mm, with an average length of stent overlap of 25 mm. Tapered configurations were used in 43.8% of cases. The majority of limbs (62.8%) had a three-vessel runoff, 20.2% had a two-vessel runoff, and 17% has a one-vessel runoff. The Kaplan-Meier estimates of graft occlusion at 1 and 3 years were 6.3% and 16.2%, respectively. The 1- and 3-year primary patency rates were 88.2% and 72.6%, and the 1- and 3-year major adverse limb event-free survival (MALE-FS) rates were 82% and 57.4%. The 1- and 3-year survival rates were 92.9% and 76.2%, respectively. On multivariable Cox regression, aneurysm size, one-vessel runoff, and coverage below the knee were associated with a lower 3-year MALE-FS. Coverage below the knee was also associated with a lower 3-year MALE-FS. Other anatomic or technical details were not associated with limb-related events or patency.

CONCLUSIONS

This study is the largest single center analysis to describe the predictors of poor outcomes after EPAR. EPAR is a safe and effective way to treat popliteal artery aneurysms. Factors associated with poor MALE-FS after EPAR include single-vessel tibial runoff and coverage below the knee.

C-Reactive Protein to Albumin Ratio in Patients With Saphenous Vein Graft Disease

Atherosclerosis plays an important role in saphenous vein graft disease (SVGD). Previous studies showed that inflammatory blood cells play an active role in this process. C-reactive protein to albumin ratio (CAR) is considered as a novel predictor for cardiovascular risk and an indicator of inflammation. We aimed to assess the relationship between SVGD and CAR. A total of 711 participants with saphenous vein graft (SVG) were included; 348 patients had SVGD and 363 patients had patent (no stenosis) SVG. C-reactive protein to albumin ratio was higher in patients with SVGD (P < .001). There was a significant positive correlation between CAR and the age of SVG (r = 0.123; P = .001) and SYNTAX score (r = 0.568; P < .001). Multivariate logistic regression analyses showed that lymphocyte count, CAR, and SYNTAX score were independent predictors of SVGD (P < .05). C-reactive protein to albumin ratio may be a useful marker after bypass surgery to predict SVGD.

Relation between functional coronary artery stenosis and graft occlusion after coronary artery bypass grafting

OBJECTIVES

This study was conducted to evaluate graft patency rates during the 5 years after coronary artery bypass grafting according to the functional significance of the coronary artery stenosis, as determined by myocardial single-photon-emission computed tomography.

METHODS

Two hundred ninety-five patients who underwent coronary artery bypass grafting using Y-composite grafts based on the in situ left internal thoracic artery, and in whom preoperative stress/rest myocardial single-photon-emission computed tomography and 1-year angiographies were available were enrolled. Seven hundred sixty-nine and 262 distal anastomoses were constructed to ischemic and nonischemic areas, respectively. One-year and 5-year angiographic occlusion rates were evaluated in all and 80.3% of study patients, respectively. Factors associated with graft occlusion were evaluated using generalized linear mixed-effects models.

RESULTS

Overall 1- and 5-year graft occlusion rates were 4.3% (44 of 1031 distal anastomoses) and 5.5% (45 out of 820), respectively. The occlusion rates of grafts bypassed to vessels with functionally significant and insignificant stenosis were 2.7% (21 out of 769) and 8.8% (23 out of 262) at 1 year and were 4.0% (25 out of 618) and 9.9% (20 out of 202) at 5 years, respectively. Graft occlusion during the 5 years after coronary artery bypass grafting was associated with the functional significance of coronary artery stenosis (odds ratio, 0.50; 95% confidence interval, 0.28-0.92). The odds ratio of the graft occlusion according to functional ischemia was lower and significant in grafts to arteries with intermediate stenosis (stenosis ≥70% but <90%; odds ratio, 0.34; 95% confidence interval, 0.13-0.93) whereas it was higher and insignificant in grafts to arteries with severe stenosis (≥90% stenosis; odds ratio, 0.76; 95% confidence interval, 0.33-1.72).

CONCLUSIONS

Graft occlusion during the 5 years after coronary artery bypass grafting was associated with the functional significance of coronary artery stenosis, particularly when the stenosis degree was not severe.

The usefulness and feasibility of placing a clinch knot with a guidewire to achieve temporary hemostasis in arteriovenous dialysis access interventions

PURPOSE

To evaluate the usefulness and feasibility of using a reversible clinch knot with a guidewire in place rather than eliminating the access route during an arteriovenous hemodialysis access (AV access) intervention using the facing sheath technique.

MATERIAL AND METHODS

From July 2016 to June 2019, we retrospectively studied 78 sessions performed as interventional treatment for arteriovenous (AV) hemodialysis (HD) access using the "facing-sheath technique." In all sessions, all antegrade sheaths were removed while a 0.035-inch guidewire remained in place with purse-string suture and the clinch knot. Seventy-two sessions were performed in patients with thrombosed AV accesses (69 arteriovenous grafts [AVGs] and three arteriovenous fistulas [AVFs]), and six sessions were carried out to treat non-thrombosed AV accesses (four AVGs and two AVFs). We evaluated whether proper hemostasis and successful reinsertion of the sheath over the wire into the clinch knot was achieved. Clinical success was defined as achieving prompt restoration of blood flow for AV access, and the postintervention primary and secondary patency were also evaluated.

RESULT

In all 87 clinch knots created in 78 total sessions, proper hemostasis was achieved. All clinch knots that required reversal for additional procedures were successfully reopened (55 clinch knots in 50 sessions). The postintervention primary patency rates at 1, 3, and 6 months, and at 1 year were 77.8%, 68.9%, 55.6%, and 33.3%, respectively. The postintervention secondary patency rates at 1, 3, and 6 months, and also at 1 year were 93.3%, 91.1%, 86.7%, and 86.7%, respectively.

CONCLUSION

Our AV access intervention which used a clinch knot with purse-string suture while the guidewire remained in place was both useful and feasible for maintaining temporary hemostasis.

Impact of coronary total occlusion on graft failure and outcomes of coronary artery bypass grafting

OBJECTIVE

The study objective was to assess the impact of chronic total occlusion on long-term graft failure and outcomes in patients who underwent coronary artery bypass grafting.

METHODS

We conducted an observational study involving a single-center subgroup of the CORONARY trial. At 6 to 9 years after coronary artery bypass grafting, all alive patients were invited for coronary computed tomography angiography and clinical follow-up. We assessed the association between chronic total occlusion graft and failing graft showing Fitzgibbon type B or O. Risk factors associated with chronic total occlusion graft failure were assessed. The impact of chronic total occlusion on clinical outcomes was analyzed, including death, myocardial infarction, and repeated revascularization.

RESULTS

A total of 349 patients undergoing coronary artery bypass grafting were enrolled between May 2007 and October 2011. Of 301 alive patients at follow-up time (median, 6.8 years; interquartile range, 6.0-8.0 years), repeat coronary computed tomography angiography was performed in 206 patients (68.4%) with 723 grafts (154 chronic total occlusion grafts and 569 nonchronic total occlusion grafts). Chronic total occlusion graft was significantly associated with an increased risk of long-term graft failure after adjustment for patient- and graft-level characteristics (adjusted odds ratio, 2.27; 95% confidence interval, 1.42-3.62; P < .001). Arterial graft, side-to-side anastomosis, higher graft flow, and antiplatelet therapy at discharge were associated with chronic total occlusion graft patency. The presence of 1 or more chronic total occlusions was not significantly associated with long-term composite of death, myocardial infarction, or repeat revascularization (adjusted hazard ratio, 0.91; 95% confidence interval, 0.54-1.51; P = .707).

CONCLUSIONS

Chronic total occlusion graft was associated with an increased risk of graft failure. Surgical technique and guideline-directed medical therapy should be noted to improve chronic total occlusion graft patency.

Unusual Cause of Heart Failure in a Patient with Marfan Syndrome: A Late Complication of Bioprosthetic Valved Graft Replacement

A high-velocity gradient across the left ventricular outflow tract is most often caused by aortic valve stenosis. We describe the unusual case of a high-velocity gradient caused by a kinked ascending aortic graft in a 69-year-old man who had Marfan syndrome. The patient had a history of ascending aortic aneurysm and had previously undergone replacement of the aortic root and ascending aorta with use of a bioprosthetic valved graft. The kinking was caused by dilation of the native aortic arch. The patient underwent successful hemi-arch replacement and repair of the kinked graft. Late complications and reoperation after proximal aortic surgery in patients with Marfan syndrome are rare, and a high-velocity left ventricular outflow tract gradient caused by the kinking of the aorta is unusual.

Asymptomatic, Multiple Stent Fractures of a Superficial Femoral Artery

Certain factors like ostial disease, chronic total occlusion, and long, multiple stents are the main causes of multiple stent fractures, as were present in this case. Such stent fractures are usually associated with significant in-stent restenosis; however, this patient had a patent lumen despite multiple fractures.

A Comparative Study Regarding Deep and Superficial Veins for Venous Outflow in Forearm Loop Arteriovenous Grafts

BACKGROUND

The purpose of the study was to compare the access patency rates of forearm loop arteriovenous grafts (AVGs) using deep veins and superficial veins for venous outflow.

METHODS

The medical records of patients on dialysis were retrospectively reviewed to identify the individual risk factors and the outcomes of forearm loop AVGs according to their outflow types.

RESULTS

Overall, 170 cases were enrolled in this study. Of these, 103 cases (60.6%) used deep veins for outflow. Most patients using deep vein outflow had their venous anastomosis above the elbow (P = 0.000). Patients with venous anastomosis above the elbow were more likely to be female (P = 0.049) and have a lower albumin level (P = 0.025). The primary patency rates for superficial vein outflow and deep view outflow were 35.5% and 29.4% at 12 months and 18.9% and 4.9% at 24 months, respectively. There was a statistically significant difference between the two groups (P = 0.013). The assisted primary patency rates for superficial venous outflow and deep vein outflow were 85.5% and 79.5% at 12 months and 73.2% and 59.6% at 24 months, respectively (P = 0.139). Primary and assisted primary patency rates did not differ according to the crossing of the elbow.

CONCLUSIONS

The primary patency rate of AVGs using deep veins for outflow was inferior to AVGs using superficial veins. But the assisted primary patency rate showed no difference. The use of a deep vein for outflow in the forearm loop AVG is a safe strategy for patients with exhausted superficial veins.