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.

De novo central vein stenosis in hemodialysis patients following initial tunneled central vein catheter placement

Background: Central vein stenosis (CVS) is a common complication in hemodialysis patients following tunneled central venous catheter (CVC) insertion. Little is known about its incidence, association with patient characteristics, or relationship with duration of CVC placement. We systematically evaluated central vein stenosis in hemodialysis patients receiving their first CVC exchange at a large medical center. Methods: All new hemodialysis patients underwent an ultrasound prior to their internal jugular tunneled CVC placement, to exclude venous stenosis or thrombosis. After the initial CVC insertion, if the patients were referred for CVC exchange due to dysfunction, a catheterogram/venogram was performed to assess for hemodynamically significant (>50%) central vein stenosis. During a five-year period (January 2016 to January 2021), we quantified the incidence of CVS in patients undergoing CVC exchange. We also evaluated the association of central vein stenosis with patient demographics, comorbidities, and duration of CVC dependence prior to exchange. Results: During the study period, 273 patients underwent exchange of a tunneled internal jugular vein CVC preceded by a catheterogram/venogram. Hemodynamically significant CVS was observed in 36 patients (13%). CVS was not associated with patient age, sex, race, diabetes, hypertension, coronary artery disease, peripheral artery disease or CVC laterality. However, the frequency of CVS was associated with the duration of CVC dependence (26% vs 11% for CVC duration >6 vs <6 months: odds ratio (95% CI), 3.17 (1.45 to 6.97), p=0.003). Conclusions: Among incident hemodialysis patients receiving their first tunneled internal jugular CVC exchange, the overall incidence of de novo hemodynamically significant central vein stenosis was 13%. The likelihood of CVS was substantially greater in patients with at least 6 months of CVC dependence.

Treatment of an Unyielding Central Vein Stenosis using Valvuloplasty Balloon in a Young Female Presenting with Ineffective Hemodialysis

Percutaneous balloon venoplasty is widely employed for the management of central vein stenosis (CVS), a condition frequently encountered in patients on maintenance hemodialysis (MHD). The hypertrophied and fibrotic venous stenotic lesions often pose a challenge for interventionists, due to resistance to dilatation and high-elastic recoil. We report here successful utilization of mitral valvuloplasty balloon for percutaneous treatment of an unyielding brachiocephalic vein stenosis. Repeated failure of conventionally used peripheral balloon dilatation catheter prompted the use of a mitral valvuloplasty balloon that could exert higher radial pressure while preventing melon-seeding and hence successfully achieve stenosis dilatation. The mitral valvuloplasty balloon can be effectively and safely used for lesions resistant to repeated dilatations by conventional peripheral balloons. Rheological stress on central veins from ipsilateral arteriovenous fistula (AVF) may result in development of stenotic lesions, even in the absence of prior venous catheterization of the affected vein; therefore, in the presence of relevant symptoms, this diagnosis should not be excluded on the basis of absence of prior direct trauma at the stenosis site.

THREAT ANALYSIS OF REASONS LEADING TO FAILURE OF PERMANENT HEAMODIALYSIS ACCESS

Objective: To analyze the commonest threats which lead to the failure of a permanent vascular haemodialysis access. Study Design: Prospective observational study. Place and Duration of Study: Department of Vascular Surgery, Combined Military Hospital Rawalpindi, from Nov 2018 to Nov 2019. Methodology: All patients who presented with arteriovenous fistula (AVF) or arteriovenous graft (AVG) related complications which can potentially fail an access were included. The frequency, with which these complications occurred, was noted. Results: A total of 158 patients were included, 73 (46.20%) were male and 85 (53.80%) were females. The complications observed in order of frequency were arteriovenous fistulathrombosis (anastomotic or draining vein) in 60 (38%), pseudo aneurysms in 39 (24.68%), stealing veins causing non-maturity of the access in 14 (8.86%), venous hypertension causing extremity edema in 14 (8.86%) (7 due to stealing veins and 7 due to central venous stenosis), AVF anastomotic or draining vein stenosis in 8 (5.06%), wound hematoma in 5 (3.16%), wound infection in 5 (3.16%), true aneurysm of the draining vein in 4 (2.56%), steal syndrome in 3 (1.9%), wound seroma in 3 (1.9%), post op arm edema(not related to central vein stenosis orstealing veins) in 2 (1.26%) and compression neuropathy in 1 (0.6%) of the patients. Conclusion: Complications of vascular access are the potential threats to the life of a permanent vascular access. Early diagnosis and timely intervention can help in fistula salvage.

MO764AVF VOLUME BLOOD FLOW REDUCTION AS THE FIRST STAGE OF TREATMENT OF CENTRAL VEIN STENOSIS IN HD PATIENTS

Background and Aims It is well-known that central vein stenosis (CVS) significantly reduces the time of AVF functioning. At the same time, according to current guidelines (KDIGO, European Vascular Surgery Society, European Best Clinical Practice), only clinically significant CVS should be treated. Often, CVS becomes clinically manifest due to a significant increase of AVF volume blood flow (Qa) through the matured dialysis access. Aim: to assess the effect of Qa reduction on the CVS clinical course. Method We performed a retrospective study included 56 patients who underwent Qa reduction as the first step of treatment, and 62 patients who received endovascular interventions without Qa reduction (balloon angioplasty supplemented with stenting if necessary). Blood flow reduction was performed using banding under intraoperative ultrasound control. Results Surgical banding leads to a clinically obvious and statistically significant decrease in Qa in all patients – fig. 1. In contrast, after endovascular intervention most of the patients show a modest but statistically significant increase in Qa - fig. 2. All surgeries were performed to reduce the severity of clinical manifestations of CVS. AVF was better available for immediate cannulation after endovascular interventions than after banding: RR=4,537 [95%CI 1,416; 14,84], p=0,0116. However, the probability of successful cannulation at the third postoperative HD session did not differ between groups: RR=3.024 [95%CI 0.674; 13.67], p=0.2126. Taking in consideration these findings, we can conclude that the short-term results of Qa reduction are satisfactory. After Qa reduction in case of recurrence of CVS symptoms or absence of their complete resolving, we supplemented the treatment with endovascular interventions. Both primary and secondary patency were significantly better than in the case of endovascular interventions without Qa reduction – fig. 3. Moreover, in patients who underwent endovascular interventions without Qa reduction, higher Qa values were associated with decrease of the primary and secondary patency – fig. 4. So, increasing or maintaining large Qa values after endovascular intervention may be an important risk factor for CVS relapse and AVF function loss. Conclusion Qa is an important factor of CVS clinical manifestation. When determining treatment strategy, it is necessary to evaluate Qa first and reduce it, if necessary. Manage of Qa allows to transfer manifest CVS into its subclinical course, which itself leads to improved treatment results. Endovascular interventions are the preferred treatment of CVS with clinical manifestations in a case of underlying normal or suboptimal Qa.

Bilateral brachiocephalic vein stenosis in a chronic hemodialysis patient with well-functioning arteriovenous fistula – A rare entity

<b>Introduction:</b> Central vein stenosis has been reported in patients of end stage renal disease with subclavian vein being more commonly affected than brachiocephalic vein. <br><b>Case report:</b> We present a case of young female with bilateral brachiocephalic vein obstruction following arteriovenous fistula creation for hemodialysis.

P1329STENTING VERSUS ISOLATED BALLOON ANGIOPLASTY FOR CENTRAL VEIN STENOSIS IN HEMODIALYSIS PATIENTS

Background and Aims comparative analysis of the results of isolated balloon angioplasty (BA) and BA with stenting of central veins stenosis in patients on hemodialysis. Method A retrospective study included 62 patients with confirmed stenosis of the central veins: subclavian, brachiocephalic veins, vena cava inferior, or multiple lesions. In 39 patients, stents are not used; isolated balloon angioplasty (BA) was performed. In 23 patients we used bare metal stents. Results Functional primary patency (the time interval between the start of AVF using and the first endovascular intervention) did not differ in the groups – fig. 1A; HR 1.142 [95% CI 0.6875; 1.897], p = 0.5994. The use of stents leads to increase primary patency (the time interval between the first and second endovascular interventions) – fig. 1B; HR 2.064 [95% CI 1.252; 3.404], p = 0.0017. The use of stents allows to increase the functional secondary patency (total duration of use of the AVF) – fig 1C; HR 2.099 [95% CI 1.272; 3.463], p = 0.0016. Secondary patency (the time interval between the first endovascular intervention and the complete cessation of the use of AVF) was higher after BA with stenting: HR 2.03 [95% CI 1.232; 3.347], p = 0.0021; fig 1D. The use of stents allows to increase functional primary assisted patency (non-occlusive period from the start of AVF use) – fig. 1E and primary assisted patency (non-occlusive period from the first surgical intervention) – fig 1F: HR 1.936 [95% CI 1.175; 3.188], p= 0.0053 and HR 2.0 [95% CI 1.213; 3.295], p = 0.0042. The need for open reconstructive interventions after the first BA or BA with stenting was the same 0.374 [95% CI 0.24; 0.556] and 0.45 [95% CI 0.291; 0.664] per 10 patient-months, incidence rate ratio (IRR)= 0.831 [95% CI 0.471; 1.464] р=0.521. The need for endovascular interventions did not differ between isolated BA and BA with stenting 1.137 [95% CI 0.8913; 1.43] and 0.827 [95% CI 0.606; 1.104] per 10 patient-months, IRR=1.374 [95% CI 0.952; 1.999] p=0.09. Total need for surgical interventions (open + endovascular) also did not differ: 1.511 [95% CI 1.225; 1.843] and 1.277 [95% CI 0.997; 1.611] per 10 patient-months, IRR 1.183 [95% CI 0.872; 1.612] p=0.2822. We found a strong negative correlation between functional primary patency and primary patency (r = -0.627; p &lt;0.0001) – fig. 2, as well as a between functional primary patency and secondary patency in patients after isolated BA (= -0.53; p = 0.0005, respectively), but not after stenting (r = -0.351; p = 0.101 and r = -0.304; p = 0.159, respectively). In a case of isolated BA, the success of the first intervention largely determines the secondary patency, which is expressed in a strong, statistically significant positive correlation of primary patency and secondary patency. In a case of BA with stenting, the correlation between these estimates is also statistically significant, but significantly lower. Conclusion 1. The results of balloon angioplasty without stenting are significantly influenced by the duration of the period between the start of AVF use and the manifestation of central vein stenosis. 2. The use of stents can slightly improve the results of endovascular interventions in central vein stenosis, regardless the its time of development. 3. The use of stents leads to a moderate increase in the median patency of AVF and a significant increase in the proportion of patients with functional AVF in the late postoperative period. 4. The use of stents does not reduce the need for surgical interventions

P1319AMBIGUOUS RESULTS OF CENTRAL VEIN STENOSIS ENDOVASCULAR TREATMENT IN HEMODIALYSIS PATIENTS

Background and Aims Balloon angioplasty (BA) without the use of stents has unsatisfactory results, which may cast doubt on its expediency. At the same time, BA is a very expensive treatment method. We conducted a comprehensive comparative analysis of the native arteriovenous fistula (AVF) patency rates in hemodialysis patients with central venous stenosis (CVS) after endovascular BA and «open» palliative surgery. Method A retrospective study included 80 patients with confirmed central vein stenosis: subclavian, brachiocephalic veins, vena cava inferior, or multiple lesions. The main group included 39 patients who underwent percutaneous balloon angioplasty. The control group included 41 patients who did not have balloon angioplasty for various reasons. In this patients we performed only «open» palliative interventions: thrombectomy, proximalization of arteriovenous anastomosis, AVF blood flow reduction. Results Functional primary patency (the time interval between the start of AVF using and the first intervention) did not differ: groups were comparable in time of stenosis manifestation (fig. 1A). Primary patency (the time interval between the first and second interventions) after BA was statistically significantly better than in the main group (fig. 1B), but difference was minimal: median survival in the study group of 8 months [95% CI 6; 10] vs. - 6 months [95% CI 4.9; 7.1]. There was the strong negative correlation between the primary patency and functional primary patency in the main group (r = –0.627 [95%CI –0.787; –0.388], p &lt;0.0001) but not in the control group (r = 0.049 [95%CI –0.262; –0.351], p = 0.7599). Thus, the later manifestation of CVS related with lower effectiveness of BA. The functional secondary patency (total duration of AVF use) in the main group was significantly better: median survival was 47 months [95% CI 40.9; 53.1] vs. 34 months [95% CI 29.8; 38.2] as well as secondary patency (the time interval between the first intervention and the complete cessation of AVF use): median survival was 16 months [95% CI 12.5; 19.5] vs. 7 months [95% CI 4.9; 9.1] (fig. 1 C and D). The occlusion-free period from the moment of starting the AVF use (functional primary assisted patency – fig. 1E) was higher in the main group, but difference was minimal: median survival was 39 months [95% CI 36.5; 41.5] vs. 32 months [95% CI 27.5; 36.5], as well as occlusion-free period from the moment of the first surgical intervention (primary assisted patency – fig. 1F) median survival was 9 months [95% CI 7; 11], in the control group - 7 months [95% CI 5.6; 8.4]. The need for open interventions was lower in the main group: 0.374 [95% CI 0.24; 0.556] and 2.451 [95% CI 1.1963; 3.023] per 10 patient-months, incidence rate ratio (IRR)= 0.153 [95% CI 0.095; 0.237], р&lt;0.0001; as well as overall need for interventions: 1.511 [95% CI 1.225; 1.843] and 2.451 [95% CI 1.963; 3.023] per 10 patient-months, IRR 0.617 [95% CI 0.461; 0.825] p=0.0011. The value of AVF volume blood flow had a strong negative correlation with the primary patency in both groups (r = –0.529, p =0.0027; r = –0.419, p =0.0101). Conclusion 1. Central vein stenosis is inevitably leads to loss of vascular access on the ipsilateral side. 2. Balloon angioplasty allows to extend the period of AVF use but it is not a radical treatment method of CVS. 3. The results of balloon angioplasty are significantly affected by the length of the period from the start of AVF use to the CVS manifestation. 4. Multiple repeated BA are apparently justified in patients for whom the possibility of creating a new vascular access is doubtful. 4. The AVF volume blood flow is an important factor determining the severity of CVS clinical manifestations and the need for repeated surgical interventions.