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.

Vascular access creation in octogenarians: The effect of age on outcomes.

BACKGROUND: The prevalence of end-stage renal disease is accelerating among older age groups. Patient-specific factors in the elderly patient group might advocate for a different vascular access creation approach, in which patency, risk of nonmaturation, and time to cannulation with accompanied prolonged catheter use should be of primary importance. The aim of this study was to determine which vascular access has the best outcomes and to determine whether age is associated with different outcomes after vascular access surgery. METHODS: Data were obtained from a prospectively maintained database of patients treated between November 2004 and December 2017. Two different patient groups were identified: the octogenarian group, consisting of patients aged ≥80 years; and the control group, consisting of all the other patients. A total of 694 vascular access procedures were included in this study, 65 in the octogenarian group and 629 in the control group. Primary, primary assisted, and secondary patency rates were calculated and compared between groups and vascular accesses. Multivariable analysis was used to determine whether age is an effect modifier in the association between type of vascular access and different patency outcomes. RESULTS: Mean follow-up was 23.2 months in the octogenarian group and 21.2 months in the control group (P = .210). No significant differences were found in patient survival, with a 5-year survival rate of 63.8% (±5.9%) in the octogenarian group and 57.2% (±2.2%) in the control group (P = .866). Within the octogenarian group, primary failure rate was highest in the radiocephalic arteriovenous fistula (AVF) patients, 42.1% (P = .006). Brachiocephalic AVF had significantly improved assisted patency compared with the other vascular accesses among the octogenarians (P = .016). Age was not an effect modifier in the association between type of vascular access and different patency outcomes. The adjusted analysis, corrected for octogenarian age, diabetes mellitus, hypertension, and sex, showed that brachiocephalic AVF was significantly associated with an increase in primary patency (hazard ratio, 0.70; 95% confidence interval, 0.54-0.90; P = .006) and primary assisted patency (hazard ratio, 0.58; 95% confidence interval, 0.39-0.86; P = .006) compared with other vascular accesses. CONCLUSIONS: The results of our study support primary placement of a brachiocephalic AVF in the octogenarian patient. A low primary failure rate was achieved with significant improved patency rates compared with the other vascular accesses.

Outcomes after endovascular mechanical thrombectomy in occluded vascular access used for dialysis purposes.

PURPOSE: Endovascular mechanical thrombectomy using the AngioJet™ system can be considered to reestablish patency in occluded vascular access. The aim of this study was to review our results for endovascular mechanical thrombectomy using the AngioJet™ system in patients with arteriovenous fistulae (AVF) and arteriovenous grafts (AVG). METHODS: Data collected in a database of patients requiring hemodialysis for renal failure were analyzed. Patients who underwent endovascular mechanical thrombectomy procedures with the AngioJet™ system for occlusion of vascular access were included. Clinical and technical success rates and patency rates were calculated. Multivariate analysis was used to identify factors of influence. RESULTS: A total of 92 AngioJet™ procedures in 60 patients with thrombosed vascular access were reviewed during a mean follow-up period of 21.5 months in patients with an AVF and 11.9 months in patients with an AVG. Technical and clinical success was achieved in 92.6% of AVF cases and 92.0 and 90.8% of AVG cases with an AVG, respectively. Significantly higher primary and primary-assisted patency rates were observed in the AVF group. Multivariate regression analysis indicated that left-sided vascular access and female sex were independent predictors for failure regarding primary patency in AVG patients. Immunosuppressive drugs and older age were negative predictors for secondary patency in AVG patients. CONCLUSIONS: The AngioJet™ system can be deemed an effective technique to reestablish patency in occluded vascular access with minimal use of central venous catheters for dialysis. Good technical and clinical success rates were achieved with acceptable patency rates, especially in AVF patients.

Outcomes of basilic vein transposition versus polytetrafluoroethylene forearm loop graft as tertiary vascular access.

BACKGROUND: Radial-cephalic arteriovenous fistula and brachial-cephalic arteriovenous fistula are the first and second choices for creating vascular access in dialysis patients as recommended by the National Kidney Foundation Kidney Disease Outcomes Quality Initiative. Basilic vein transposition or use of a forearm (polytetrafluoroethylene [PTFE]) loop graft is recommended thereafter. The aim of this study was twofold: first, to compare the outcomes and patency rates of patients treated with a basilic vein transposition with those of patients treated with a PTFE loop; and second, to identify patient-related factors of influence on patency rates. METHODS: Data collected in our prospectively maintained database of patients with chronic renal dysfunction requiring hemodialysis were analyzed. From April 2006 to August 2017, there were 55 patients with a basilic vein transposition and 75 patients with a PTFE loop included. Primary, primary assisted, and secondary patency rates were calculated. Multivariate analysis was used to identify factors of influence on survival. Incidence rates of complications and reinterventions were calculated and compared. RESULTS: Mean follow-up time was 29 months. A significantly higher 2-year primary assisted patency rate was found for the basilic vein transposition group (72.7% ± 6.5% vs 47.6% ± 6.2%; P < .01). The 2-year primary patency rates and secondary patency rates were comparable between basilic vein transposition and PTFE loop (25.1% ± 6.6% vs 13.7% ± 4.4% [P = .11] and 75.5% ± 6.5% vs 73.9% ± 5.3% [P = .17], respectively). Cox regression identified body mass index (hazard ratio [HR], 1.77; 95% confidence interval [CI], 1.05-2.98; P = .03) and age (HR, 0.54; 95% CI, 0.32-0.91; P = .02) as predictors for failure regarding primary patency in PTFE loop patients. Previous catheter use (HR, 0.29; 95% CI, 0.12-0.70; P = .006) and the presence of diabetes (HR, 3.32; 95% CI, 1.50-7.39; P = .003) were independent predictors for failure regarding primary patency in basilic vein transposition patients. The incidence rate of total complications was significantly higher in the PTFE loop group with 0.70 per patient-year (PY-1) compared with 0.28 PY-1 in the basilic vein transposition group (P = .001). In terms of intervention rate, a significantly higher percutaneous transluminal angioplasty rate and surgical revision rate were found in the PTFE loop group than in the basilic vein transposition group (1.77 PY-1 vs 1.05 PY-1 [P = .022] and 0.20 PY-1 vs 0.07 PY-1 [P = .002], respectively). CONCLUSIONS: In this nonrandomized study, basilic vein transposition has better primary assisted patency, fewer complications, and fewer reinterventions compared with PTFE loop.

Differences in shuntflow (Qa), cardiac function and mortality between hemodialysis patients with a lower-arm fistula, an upper-arm fistula, and an arteriovenous graft.

BACKGROUND: High-flow vascular accesses may contribute to cardiovascular morbidity and mortality in hemodialysis patients. Since shuntflow (Qa) varies between vascular access types, the current study aims to investigate differences in left ventricular hypertrophy (LVH), systolic and diastolic function parameters, and all-cause mortality between patients with a lower-arm arteriovenous fistula (AVF), an upper-arm AVF, and an arteriovenous graft (AVG). METHODS: A post hoc analysis of 100 patients was performed in a single-center, prospective observational study. Echocardiography examinations were performed prior to the dialysis session. Qa measurements were performed using ultrasound dilution. Patient groups were categorized by vascular access type. Cox proportional hazards models were used to investigate the association of shunt type with all-cause mortality with adjustment for potential confounders including, amongst others, age, sex, diabetes, the duration of hemodialysis treatment, shunt vintage, and Qa. RESULTS: Patients with an upper-arm AVF had significantly (p < 0.001) higher Qa (median 1902, IQR 1223-2508 ml/min) compared to patients with a lower-arm AVF (median 891, IQR 696-1414 ml/min) and patients with an AVG (median 881, IQR 580-1157 ml/min). The proportion of patients with LVH and systolic and diastolic echocardiographic parameters did not differ significantly between groups. Survival analysis showed that an upper-arm AVF was associated with a significantly lower all-cause mortality (p = 0.04) compared to a lower-arm AVF. CONCLUSIONS: Patients with an upper-arm fistula had a higher Qa but similar systolic and diastolic cardiac function. Patients with an upper-arm fistula had a significantly lower risk of all-cause mortality compared with patients with a lower-arm fistula.

Similar outcomes of arteriovenous fistulae created under general or regional anesthesia.

BACKGROUND: There is growing evidence that type of anesthesia can significantly change vascular access surgery outcomes. Still, there is limited evidence on the impact of regional anesthesia (RA) on patency and failure rates compared to general anesthesia (GA). The aim of this study was to compare the outcomes of RA and GA in patients who underwent vascular access creation at our center. METHODS: Data collected in our prospectively maintained database of patients with chronic renal dysfunction requiring hemodialysis were analyzed, 464 patients were included. Outcome parameters such as maturation, primary failure, postoperative flow measurements, patency rates, and survival outcomes were compared between RA and GA groups. RESULTS: In this study 489 vascular access procedures were performed in 464 patients, 318 included in the RA group and 171 in the GA group. Median follow-up time was 29.9 (IQR 37.3) months in the RA group versus 33.0 (IQR 40.7) in the GA group (p = 0.252). Anesthesia type did not significantly affect patient survival (HR, 1.01; CI, 0.70-1.45; p = 0.976). No significant differences were found in vascular access flow volume, primary failure, or time to cannulation between the RA and GA groups for both radiocephalic arteriovenous fistulae and brachiocephalic arteriovenous fistulae. Anesthesia type did not significantly change patency outcomes. CONCLUSIONS: Based on our results, both RA and GA demonstrate similar results regarding patient survival, maturation, failure, or patency after vascular access creation. Still, patient-specific factors for each type of anesthesia as well as patient preference should be considered.

Endothelial progenitor cell dysfunction in patients with progressive chronic kidney disease.

Endothelial progenitor cells (EPC) contribute to repair and maintenance of the vascular system, but in patients with chronic kidney disease (CKD), the number and function of EPC may be affected by kidney dysfunction. We assessed numbers and the angiogenic function of EPC from patients with CKD in relation to disease progression. In a cross-sectional, prospective study, 50 patients with varying degrees of CKD, including 20 patients undergoing dialysis and 10 healthy controls, were included. Mononuclear cells were isolated, and circulating EPC were quantified by flow cytometry based on expression of CD14 and CD34. EPC were cultured on fibronectin-coated supramolecular films of oligocaprolactone under angiogenic conditions to determine their angiogenic capacity and future use in regenerative medicine. CKD patients had normal numbers of circulating CD14+ EPC but reduced numbers of circulating CD34+ EPC. Furthermore, EPC from patients with CKD displayed functional impairments, i.e., hampered adherence, reduced endothelial outgrowth potential, and reduced antithrombogenic function. These impairments were already observed at stage 1 CKD and became more apparent when CKD progressed. Dialysis treatment only partially ameliorated EPC impairments in patients with CKD. In conclusion, EPC number and function decrease with advancing CKD, which may hamper physiological vascular repair and can add to the increased risk for cardiovascular diseases observed in CKD patients.