Arterial revascularization in patients with hand pain dialyzing with upper arm Arteriovenous (AV) fistulas: A single center experience.

BACKGROUND: Distal hand ischemia syndrome (DHIS) is a well reported adverse outcome in patients with upper arm AV access. 25%-40% of these patients have been reported to be due to primary arterial disease complicated with significant arterial calcification. The effectiveness of revascularization of the distal arterial circulation on symptom resolution has not been reported yet. METHODS: Retrospective single center analysis of patients evaluated for hand/forearm pain in patients with upper arm AV access who had arterial revascularization between 01/2016 and 12/2020 were included for the analysis. Fifty-one patients met inclusion criteria. Stenotic lesions greater than 70% in the subclavian, axillary, brachial, radial, or ulnar artery were treated with balloon angioplasty. Institutional approval was obtained to review charts. OUTCOMES: Successful revascularization, improvement in pain in 48 h, 1 month, and 3 months. RESULTS: Seventy six percent of patients had an upper arm Arteriovenous Fistula (AVF) and 24% patients had an upper arm Arteriovenous Graft (AVG). Mean access flow was 1210 (556) ml/min. 55% of patients had radial or ulnar arterial stenosis, 45% had brachial/axillary or subclavian artery stenosis. 45% patients had lesions in both radial and ulnar arteries, 88% of patients were successfully revascularized. 76% (18) of patients had improvement in symptoms within 48 h and 68% remained symptom free in 3 months. Mean DHIS stage was 3.1 before intervention and improved to 1.1 post intervention (p < 0.001). Patient satisfaction with their AV access improved from 34% to 72% (p < 0.01). Multiple regression analysis did not reveal statistically significant correlations between time on dialysis vintage and other chronic medical conditions on post procedure symptom improvement. CONCLUSIONS: DHIS with occlusive arterial disease can be successfully revascularized to improve symptoms. Complete evaluation of the inflow arterial segment and optimal endovascular revascularization could decrease the need for access revision procedures or access abandonment.

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.

Utility of a ML analytics on real time risk stratification and re-intervention risk prediction on AV access outcomes and cost.

BACKGROUND: Vascular access is the lifeline for patients on hemodialysis. The average survival rates of dialysis dependent patients have been improving over the last 5 years and hence their dialysis access needs longevity for uninterrupted optimal dialysis. With the lack of genomic vascular access failure predictors, there is an unmet need for predicting an event and the appropriate approach to mitigate recurrence of the event that could have cost and outcome implications. METHODS: We performed a single center experience that extracted relevant clinical (access flow, laboratory data and CKD details), access intervention (prior interventions, type & location of lesion, type of balloon used, use of stents etc.) and demographic (age, vintage on dialysis, sex, social determinants, other medical conditions) data in real time and feeds it into validated ML algorithms to predict risk of reintervention. (Plexus EMR LLC). RESULTS: About 200 prevalent hemodialysis patients with a AV graft or AV fistula were included for this analysis. Need for re-intervention and use of stent/ flow reduction/new access creation were the outcomes analyzed. Plexus EMR is a licensed Azure based platform. R software was used to develop the ML algorithms. Regression factors were developed to assess and test the validity of individual attributes across all the data attributes. Each patient had a real time risk calculator available to the interventionalist on risk of reintervention/ year. Of the 200 patients, 148 had a AV fistula and the remaining 52 had a AV graft. Mean interventions in the year prior to analysis was 1.8 in patients with AV fistulas and 3.4 in AV grafts which decreased to 1.1 in AV fistulas and to 2.4 in AV grafts (p < 0.01) post tool deployment. There were 62 AV graft thrombectomies done in the observation year and 62% of those were repeat thrombectomies. Stent utilization increased to 37 (22 in AV grafts and 15 in AV fistulas) and 2 patients had AV access flow reduction surgery. The cumulative cost (predicted) preintervention was $712,609 and decreased to $512,172 post intervention. Stent utilization increased by 68% in the evaluation year and 89% of the stents used were PTFE coated stents. CONCLUSION: Utilizing AI with ML based algorithms that includes clinical, demographic and patency maintenance variables could become new standards of care to optimally manage AV accesses and lower cost of care.

Prospective, Multicenter Clinical Study of the Covera Vascular Covered Stent in the Treatment of Stenosis at the Graft-Vein Anastomosis of Dysfunctional Hemodialysis Access Grafts.

PURPOSE: To study the use of the self-expanding Covera covered stent for the treatment of stenotic lesions at the venous anastomosis of hemodialysis arteriovenous grafts (AVGs). MATERIALS AND METHODS: A total of 110 patients with AVG venous anastomotic stenosis of ≥50% and access dysfunction were treated at 14 centers in the United States using percutaneous transluminal angioplasty followed by covered stent placement. The primary end points were 30-day safety and 6-month target lesion primary patency (TLPP). The secondary measures included access circuit primary patency, circuit cumulative patency, and the number of reinterventions through 24 months. RESULTS: Freedom from a primary safety event at 30 days was 96.4% while the 6-month TLPP rate was 70.3%. Seventy-five patients completed 24-month follow-up (68.2%). The TLPP rates were 54.2% at 365 days and 36.9% at 730 days while the access circuit primary patency rates were 16.7% at 365 days and 7.8% at 730 days (Kaplan-Meier analysis). The access circuit cumulative patency rates were 85.4% at 12 months and 73.6% at 24 months. The number of reinterventions to maintain the patency of the access circuit was 3.6 ± 3.1 at 24 months (1.6 ± 1.9 at the target lesion). CONCLUSIONS: Use of the Covera covered stent for hemodialysis graft-vein anastomotic stenosis provided a safe treatment option with a TLPP rate of 70.3% at 6 months and TLPP and cumulative access circuit patency rates of 36.9% and 73.6% at 2 years.

American Association of Kidney Patients survey of patient preferences for hemodialysis vascular access.

OBJECTIVES: To determine the vascular access modalities used for hemodialysis, the reasons for choosing them, and determinants of satisfaction with vascular access among patients with end-stage renal disease. METHODS: The American Association of Kidney Patients Center for Patient Research and Education used the American Association of Kidney Patients patient engagement database to identify eligible adult hemodialysis patients. Participants completed an online survey consisting of 34 demographic, medical history, and hemodialysis history questions to determine which vascular access modalities were preferred and the reasons for these preferences. RESULTS: Among 150 respondents (mean age 54 years, 53% females), hemodialysis was most frequently initiated with central venous catheter (64%) while the most common currently used vascular access was arteriovenous fistula (66%). Most (86%) patients previously received an arteriovenous fistula, among whom 77% currently used the arteriovenous fistula for vascular access. Older patients and males were more likely to initiate hemodialysis with an arteriovenous fistula. The factors most frequently reported as important in influencing the selection of vascular access modality included infection risk (87%), physician recommendation (84%), vascular access durability (78%), risk of complications involving surgery (76%), and impact on daily activities (73%); these factors were influenced by patient age, sex, and race. Satisfaction with current vascular access was 90% with arteriovenous fistula, 79% with arteriovenous graft, and 67% with central venous catheter. CONCLUSION: Most end-stage renal disease patients continue to initiate hemodialysis with central venous catheter despite being associated with the lowest satisfaction rates. While arteriovenous fistula was associated with the highest satisfaction rate, there are significant barriers to adoption that vary based on patient demographics and perception of procedure invasiveness.

Patient selection, education, and cannulation of percutaneous arteriovenous fistulae: An ASDIN White Paper.

End-stage kidney disease patients who are candidates for surgical arteriovenous fistula creation commonly experience obstacles to a functional surgical arteriovenous fistula, including protracted wait time for creation, poor maturation, and surgical arteriovenous fistula dysfunction that can result in significant patient morbidity. The recent approval of two endovascular devices designed to create a percutaneous arteriovenous fistula enables arteriovenous fistula creation to be placed in the hands of interventionalists, thereby increasing the number of arteriovenous fistula providers, reducing wait times, and allowing the patient to avoid surgery. Moreover, current studies demonstrate that patients with percutaneous arteriovenous fistula experience improved time to arteriovenous fistula maturation. Yet, in order to realize the potential advantages of percutaneous arteriovenous fistula creation within our hemodialysis patient population, it is critical to select appropriate patients, ensure adequate patient and dialysis unit education, and provide sufficient instruction in percutaneous arteriovenous fistula cannulation and monitoring. In this White Paper by the American Society of Diagnostic and Interventional Nephrology, experts in interventional nephrology, surgery, and interventional radiology convened and provide recommendations on the aforementioned elements that are fundamental to a functional percutaneous arteriovenous fistula.

Continuation of Chronic Heart Failure Therapies During Heart Failure Hospitalization - a Review.

Randomized controlled trials have demonstrated the benefits of guideline-directed medical therapy in the outpatient setting for treatment of chronic heart failure. However, the benefits of continuation (or discontinuation) of major chronic heart failure therapies when treating acute heart failure during hospitalization are less clear. Real and anticipated worsening renal function, hyperkalemia and hypotension are the three major reasons for discontinuation of renin-angiotensin-aldosterone system inhibitors during hospitalization, and a failure to resume renin-angiotensin-aldosterone system inhibitors before discharge could worsen cardiovascular outcomes. Available data, mostly observational, shows that continuation or initiation of renin-angiotensin-aldosterone system inhibitors appears efficacious, safe, and well tolerated in majority of acute heart failure patients during hospitalization. Worsening renal function portends poor prognosis only if associated with congestion in acute heart failure, and clinicians should not de-escalate diuretic therapy routinely for worsening renal function.

Clinical predictors of recurrent stenosis and need for re-intervention in the cephalic arch in patients with brachiocephalic AV fistulas.

INTRODUCTION: Cephalic arch stenosis is one of the most common reasons for repeated endovascular intervention and eventual abandonment of access in hemodialysis patients. There is no prediction model to identify risk factors for recurrent cephalic arch stenosis. We have developed a mathematical model to predict the need for reintervention in brachiocephalic (BC) fistulas with recurrent cephalic arch stenosis. METHODS: Single-center retrospective analysis of 143 patients with a BC fistula referred to the vascular clinic for access dysfunction who underwent cephalic arch angioplasty were included for the analysis. Twelve-month post-index angioplasty data were analyzed using parametric, non-parametric and multiple regression models using SPSS software. RESULTS: The mean need for re-intervention in 1 year since first index visit was 2.46 ± 1.404. Statistically significant correlation (p≤0.001) for re-intervention was observed with the severity of stenosis at index visit, access flow, vessel wall diameter proximal to the stenosis, average venous pressure >50% of the delivered blood flow rate and prolonged bleeding for >30 minutes as a reason for referral. Three equations have been derived for calculating the need for re-intervention based on the diameter of the vessel wall proximal to the stenosis. CONCLUSIONS: Risk stratification of BC fistulas utilizing the above parameters could enable clinicians to identify accesses that are at risk for multiple re-interventions. Early identification of accesses that are at high risk for re-interventions at the cephalic arch might prolong access survival and reduce the cost for intervention by utilizing alternate strategies.

Self-centering split-tip catheter versus conventional split-tip catheter in prevalent hemodialysis patients.

PURPOSE: This study compared the patency of a split-tip self-centering catheter with a predesigned curve (CentrosFLO; Merit, Salt Lake City, Utah) and a standard split-tip catheter with straight distal limbs (Medcomp, Harleysville, Pennsylvania) catheter in patients requiring exchange of a dysfunctional tunneled dialysis catheter (TDC). MATERIALS AND METHODS: A single-center retrospective chart review was performed between January 2013 and July 2014. Patients had an existing dysfunctional TDC that was exchanged over a wire using the same access site for either a split-tip self-centering catheter with a predesigned curve or a standard split-tip catheter with straight distal limbs catheter. The primary endpoint was catheter patency analyzed at 1, 3, and 6 months after initial exchange. RESULTS: A total of 73 patients met inclusion criteria (46 in the self-centering catheter group and 27 in the standard split-tipped group). Mean durations of the exchanged catheters were similar between groups. The mean 1-, 3-, and 6-month patency rates for the self-centering and split-tip catheters were 89%, 67.4%, and 23.9% and 81.5%, 40.7%, and 14.8%, respectively. Mean blood flow rates (BFRs) were similar between groups at 1 and 3 months; however, at 6 months, mean rates were 388 mL/min versus 352 mL/min for the self-centering group and split-tipped group, respectively (p<0.01). CONCLUSIONS: These results demonstrate improved patency with the CentrosFLO self-centering catheter versus the split-tip catheter. This may be due to the unique design of the self-centering catheter, allowing for preserved BFRs and patency. These results should be further explored in prospective, randomized multicenter studies.

Flow reduction in high-flow arteriovenous fistulas improve cardiovascular parameters and decreases need for hospitalization.

High output heart failure (HF) and pulmonary hypertension have been demonstrated in patients with prevalent arteriovenous (AV) fistulas. Fistulas with flow >2000 mL/minutes are more likely to induce changes in cardiac geometry and pulmonary artery pressure. The effects of reducing flow in AV access and its implications on HF decompensation and hospitalizations have not been studied. Retrospective analysis of 12 patients who needed hospitalization for acute Congestive Heart Failure (CHF) decompensation with AV access flow of 2 L/minutes (as defined by Kidney Disease Outcomes Quality Initiative (KDOQI)) or more were included in the study. All the patients underwent banding of their inflow at the anastomosis with perioperative access flow measurement. Follow-up period was 6 months. 2D echo was done at 6 months postbanding in addition to access flow and clinical evaluation. Complete data was available for all the 12 patients. Study data was collected on all the 12 patients. Mean age was 64.7 years. The mean access flow pre and postbanding were 3784 mL/minutes and 1178 mL/minutes, respectively (P < 0.001). Eighty percent of the patients had diabetes and 41% had coronary artery disease. There was a statistically significant decrease in cardiac output (pre = 7.06 L/minutes, post = 6.47 L/minutes P = 0.03), pulmonary systolic pressure (pre = 54 mmHg, post = 44 mmHg P = 0.02), left ventricular mass index (LVMI) (pre = 130 g/m(2) , post = 125 g/m(2) P = 0.006) and need for rehospitalization for CHF decompensation. The New York Heart Association (NYHA) staging improved by 1 stage postbanding (P = 0.002). The hospitalization rate was 3.75 ± 1.2 in the 6 months before banding and was decreased to 1.08 ± 1.2 (P = 0.002) postbanding. The hemoglobin level, predialysis systolic blood pressure, calcium phosphorous product and the use of Renin Angiotensin Aldosterone System (RAAS) blockade agents and calcium channel blockers were comparable before and after inflow banding. Flow reduction in high flow fistulas are associated with decreased LVMI and pulmonary artery pressures. There is also a significant reduction in the risk for hospitalization due to acute HF and an improvement in NYHA heart failure stage.

Coronary Revascularization in Chronic and End-Stage Renal Disease: A Systematic Review and Meta-analysis.

Patients with chronic kidney disease (CKD) and end-stage renal disease (ESRD) on dialysis have an increased risk for cardiovascular mortality and morbidity secondary to occlusive coronary artery disease. Optimal revascularization strategy is unclear in this high-risk population. We have performed a meta-analysis to compare coronary artery bypass grafting (CABG) versus percutaneous coronary intervention (PCI) in patients with ESRD and CKD. We searched PubMed, Ovid, MEDLINE, CINAHL, and EMBASE (1980-2013) and found 17 trials (N = 33,584) in the ESRD arm and 6 studies (n = 15,493) in the CKD arm. Two investigators independently collected the data. All the studies were retrospective trials. In the ESRD and CKD groups, we found significantly reduced early mortality with the PCI group with the odds ratio of 2.08 (1.90-2.26; P < 0.00001) and 2.55 (1.45-4.51; P = 0.001), respectively. Contrary to the early mortality results, we found decreased late mortality with the CABG group when compared with the PCI group [odds ratio: 0.86 (0.83-0.89; P < 0.000001) and 0.82 (0.76-0.88; P < 0.00001)] in the ESRD and CKD arm, respectively. When compared with PCI, there was decreased cardiovascular mortality with an odds ratio of 0.61 (0.40-0.92; P = 0.02) in patients who underwent CABG in ESRD population. Similar trends were observed in the incidence of myocardial infarction and repeat revascularization. There is a strong trend for decreased risk of stroke with PCI when compared with CABG in ESRD and CKD populations.

Percutaneous Peritoneal Dialysis Catheter Placement in Patients with Complex Abdomen.

Peritoneal dialysis (PD) is an effective treatment for end-stage renal disease. There are several techniques of percutaneous PD catheter placement including trocar or Seldinger techniques. Placement can be performed with fluoroscopy and/or sonography or as a blind percutaneous procedure. Historically, percutaneous PD catheters have been placed in patients even if they had prior abdominal surgeries. The outcomes of percutaneous PD catheter placement in patients with complex abdomen (patients with two or more abdominal surgeries or known adhesions) are unknown. This study was carried out to determine the outcomes of percutaneous PD catheter placements using Seldinger technique with sonography and fluoroscopy in patients with complex abdomen. Preprocedure sonography was also used to identify site of adhesions and blood vessels. The goal was to see if ultrasound and fluoroscopy would support placement of PD catheters in patients with complex abdomens. There were total of 10 catheter placements in 10 patients with complex abdomen. The initial success rate was 100%. The patients had an average of 2.8 abdominal surgeries. The mean BMI was 28.4. There were no incidences of perforation or failed placements. One catheter was replaced due to outflow failure and one patient discontinued PD due to peri-catheter leak. One year catheter survival was 80%. Our study demonstrates benefits of using ultrasonography and fluoroscopy during percutaneous PD catheter placement by the Seldinger technique in patients with complex abdomen.

Persistent Median Artery As A Cause Of Nonmaturing AV Fistula.

A 68-year-old right handed male with End-Stage Renal Disease with a left radiocephalic fistula created 8 months ago was referred for the evaluation of a nonmaturing access. Patient had an arterial anastomosis lesion that underwent successful angioplasty. Diagnostic arteriogram of the AV access extremity revealed the presence of a short radial artery and dominant common interosseous artery manifesting as a persistent median artery in the distal forearm and was anastomosed to the fistula and then continues as the median-ulnar superficial arch in the palm. Balloon angioplasty of the common interosseous artery led to a complication when the distal 30 cm of the 0.018 guide wire fractured and had to be retrieved using a snare device. In addition to anticipating and treating the common complications of vascular access procedures, it is also important to be aware of the anomalies of the distal forearm arterial anatomy and perform a detailed arterial evaluation prior to creating the arterio-venous anastomosis.

Mild Renal Artery Stenosis Can Induce Renovascular Hypertension and is Associated with Elevated Renal Vein Renin Secretion.

Renovascular hypertension is a syndrome which encompasses the physiological response of the kidney to changes in renal blood flow and renal perfusion pressure. Such physiological changes can occur with renal artery occlusion irrespective of the severity of the lesion. We have analyzed hypertensive patients with mild renal artery stenosis and compared them to patients with no stenosis. Renal vein renin sampling from catheterization of the renal vein was performed in all these patients. Patients with mild stenosis had higher renal vein renin ratio (3.01 ± 1.5) than the patients with no stenosis (1.10 ± 0.29; p = 0.002). Patients with mild stenosis were also found to have higher diastolic blood pressure and renal artery resistive indices when compared to patients with no stenosis. We therefore conclude that mild stenosis can precipitate renin-mediated hypertension in renovascular stenosis and also emphasis that parameters pertinent to renal physiology need to be evaluated before considering treatment options in patients with renal artery stenosis and medical management with RAAS blockade is the preferred modality of therapy for patients with renin-mediated hypertension.

Renal sympathetic nervous system and the effects of denervation on renal arteries.

Resistant hypertension is associated with chronic activation of the sympathetic nervous system resulting in various comorbidities. The prevalence of resistant hypertension is often under estimated due to various reasons. Activation of sympathetic nervous system at the renal- as well as systemic- level contributes to the increased level of catecholamines and resulting increase in the blood pressure. This increased activity was demonstrated by increased muscle sympathetic nerve activity and renal and total body noradrenaline spillover. Apart from the hypertension, it is hypothesized to be associated with insulin resistance, congestive heart failure and obstructive sleep apnea. Renal denervation is a novel procedure where the sympathetic afferent and efferent activity is reduced by various techniques and has been used successfully to treat drug-resistant hypertension improvement of various metabolic derangements. Renal denervation has the unique advantage of offering the denervation at the renal level, thus mitigating the systemic side effects. Renal denervation can be done by various techniques including radiofrequency ablation, ultrasound guided ablation and chemical ablation. Various trials evaluated the role of renal denervation in the management of resistant hypertension and have found promising results. More studies are underway to evaluate the role of renal denervation in patients presenting with resistant hypertension in different scenarios. Appropriate patient selection might be the key in determining the effectiveness of the procedure.

Self-centering, split-tip catheter has better patency than symmetric-tip tunneled hemodialysis catheter: single-center retrospective analysis.

The performance and safety of a new self-centering, split-tip hemodialysis tunneled catheter was compared with a symmetric-tip catheter. The new catheter has a greater separation between the arterial and venous tips, with dual apertures designed to permanently face the center of the blood vessel. The design is intended to improve dialysis efficiency by increasing flow rates while decreasing recirculation, fibrin sheath formation, thrombosis, and vessel wall occlusions. The study results indicated that the self-centering, split-tip catheter had statistically greater patency after 3 months with similar clearance, blood flow, and safety.

Circulating adipocytokines and chronic kidney disease.

BACKGROUND: Adipokines have been associated with atherosclerotic heart disease, which shares many common risk factors with chronic kidney disease (CKD), but their relationship with CKD has not been well characterized. METHODS: We investigated the association of plasma leptin, resistin and adiponectin with CKD in 201 patients with CKD and 201 controls without. CKD was defined as estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m(2) or presence of albuminuria. Quantile regression and logistic regression models were used to examine the association between adipokines and CKD adjusting for multiple confounding factors. RESULTS: Compared to controls, adjusted median leptin (38.2 vs. 17.2 ng/mL, p<0.0001) and adjusted mean resistin (16.2 vs 9.0 ng/mL, p<0.0001) were significantly higher in CKD cases. The multiple-adjusted odds ratio (95% confidence interval) of CKD comparing the highest tertile to the lower two tertiles was 2.3 (1.1, 4.9) for leptin and 12.7 (6.5, 24.6) for resistin. Median adiponectin was not significantly different in cases and controls, but the odds ratio comparing the highest tertile to the lower two tertiles was significant (1.9; 95% CI, 1.1, 3.6). In addition, higher leptin, resistin, and adiponectin were independently associated with lower eGFR and higher urinary albumin levels. CONCLUSIONS: These findings suggest that adipocytokines are independently and significantly associated with the risk and severity of CKD. Longitudinal studies are warranted to evaluate the prospective relationship of adipocytokines to the development and progression of CKD.