The Clinical and Economic Effect of Vascular Access Selection in Patients Initiating Hemodialysis with a Catheter

Patients in the United States frequently initiate hemodialysis with a central venous catheter (CVC) and subsequently undergo placement of a new arteriovenous fistula (AVF) or arteriovenous graft (AVG). Little is known about the clinical and economic effects of initial vascular access choice. We identified 479 patients starting hemodialysis with a CVC at a large medical center (during 2004-2012) who subsequently had an AVF (n=295) or AVG (n=105) placed or no arteriovenous access (CVC group, n=71). Compared with patients receiving an AVG, those receiving an AVF had more frequent surgical access procedures per year (1.01 [95% confidence interval, 0.95 to 1.08] versus 0.62 [95% confidence interval, 0.55 to 0.70]; P<0.001) but a similar frequency of percutaneous access procedures per year. Patients receiving an AVF had a higher median annual cost (interquartile range) of surgical access procedures than those receiving an AVG ($4857 [$2523-$8835] versus $2819 [$1411-$4274]; P<0.001), whereas the annual cost of percutaneous access procedures was similar in both groups. The AVF group had a higher median overall annual access-related cost than the AVG group ($10,642 [$5406-$19,878] versus $6810 [$3718-$13,651]; P=0.001) after controlling for patient age, sex, race, and diabetes. The CVC group had the highest median annual overall access-related cost ($28,709 [$11,793-$66,917]; P<0.001), largely attributable to the high frequency of hospitalizations due to catheter-related bacteremia. In conclusion, among patients initiating hemodialysis with a CVC, the annual cost of access-related procedures and complications is higher in patients who initially receive an AVF versus an AVG.

Predictors of Initiation for Predialysis Arteriovenous Fistula

BACKGROUND AND OBJECTIVES

The optimal timing of predialysis arteriovenous fistula surgery remains uncertain. We evaluated factors associated with hemodialysis initiation in patients undergoing predialysis arteriovenous fistula surgery and derived a model to predict future initiation of dialysis.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Our study retrospectively identified 308 patients undergoing predialysis arteriovenous fistula creation at a large medical center in 2006-2012 to determine whether they initiated hemodialysis. Multiple variable logistic regression analyzed which demographic and clinical factors predicted initiation of dialysis within 2 years of arteriovenous fistula surgery. A receiver operating characteristic area under the curve was used to quantify the predictive value of preoperative factors on the likelihood of initiating hemodialysis within 2 years.

RESULTS

Overall, hemodialysis was initiated within 6 months, 1 year, and 2 years in 119 (39%), 175 (57%), and 211 (68%) patients, respectively. Using multiple variable logistic regression, four factors were associated with hemodialysis initiation at 2 years: eGFR at access surgery (odds ratio, 0.45; 95% confidence interval, 0.31 to 0.64 per 5 ml/min per 1.73 m2; P<0.001), diabetes (odds ratio, 2.51; 95% confidence interval, 1.22 to 5.15; P=0.003), GFR trajectory (odds ratio, 1.54; 95% confidence interval, 1.09 to 2.17 per 3 ml/min per 1.73 m2 per year; P=0.01), and spot urine protein-to-creatinine ratio (odds ratio, 1.39; 95% confidence interval, 1.14 to 1.71 per 1 U; P<0.001). eGFR alone had a moderate predictive value for dialysis initiation (area under the curve =0.69; 95% confidence interval, 0.63 to 0.76; P<0.001), whereas the full model had a higher predictive value (area under the curve =0.83; 95% confidence interval, 0.77 to 0.88; P<0.001).

CONCLUSIONS

The likelihood of initiating hemodialysis within 2 years of predialysis arteriovenous fistula surgery is associated with eGFR at access surgery, diabetes, GFR trajectory, and magnitude of proteinuria. The combined use of all four variables improves the ability to predict future hemodialysis compared with the use of eGFR alone.

Clinical Outcomes and Economic Impact of Starting Hemodialysis with a Catheter after Predialysis Arteriovenous Fistula Creation

BACKGROUND

Patients with advanced chronic kidney disease frequently undergo arteriovenous fistula creation prior to reaching end-stage renal disease (ESRD), but some initiate hemodialysis with a central vein catheter, if their fistula is not yet usable. The clinical consequences of the delay in fistula use have not been quantified in such patients. We compared patients with pre-ESRD fistula surgery who initiated dialysis with a catheter versus a fistula in terms of the frequency of post-dialysis vascular access procedures and complications and their economic impact.

METHODS

We identified 205 patients with predialysis fistula creation from 2006 to 2012 at a large dialysis center who started hemodialysis within the ensuing 2 years. Of these, 91 (44%) initiated dialysis with a catheter and 114 (56%) with a fistula. We compared these 2 groups in terms of their annual frequency of percutaneous vascular access procedures, surgical access procedures, total access procedures, hospitalizations due to catheter-related bacteremia, and overall cost of vascular access management.

RESULTS

The 2 groups were similar in demographics, comorbidities, and fistula type. As compared to patients initiating dialysis with a fistula, those initiating with a catheter had a significantly greater annual frequency of percutaneous access procedures (1.29 [1.19-1.40] vs. 0.75 [0.68-0.82]), surgical access procedures (0.69 [0.61-0.76] vs. 0.59 [0.53-0.66]), total access procedures (1.98 [1.86-2.11] vs. 1.34 [1.26-1.44]), and hospitalizations due to catheter-related bacteremia (0.09 [0.07-0.12] vs. 0.02 [0.01-0.03]). Patients initiating dialysis with a catheter incurred a median overall annual cost of access management that was USD 2,669 higher (USD 6,372 [3,121-12,242) vs. USD 3,703 [1,867-6,953], p = 0.0001).

CONCLUSION

Among patients with predialysis fistula creation, those initiating dialysis with a catheter versus a fistula had substantially more frequent percutaneous, surgical, and total vascular access procedures, as well as hospitalizations due to catheter-related bacteremia. The annual cost of access management was substantially higher in those initiating dialysis with a catheter.

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 before 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 5-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 before 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% versus 11% for CVC duration ≥6 versus <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.

Effects of a More Selective Arteriovenous Fistula Strategy on Vascular Access Outcomes

SIGNIFICANCE STATEMENT

The optimal choice of vascular access for patients undergoing hemodialysis-arteriovenous fistula (AVF) or arteriovenous graft (AVG)-remains controversial. In a pragmatic observational study of 692 patients, the authors found that among patients who initiated hemodialysis with a central vein catheter (CVC), a strategy that maximized AVF placement resulted in a higher frequency of access procedures and greater access management costs for patients who initially received an AVF than an AVG. A more selective policy that avoided AVF placement if an AVF was predicted to be at high risk of failure resulted in a lower frequency of access procedures and access costs in patients receiving an AVF versus an AVG. These findings suggest that clinicians should be more selective in placing AVFs because this approach improves vascular access outcomes.

BACKGROUND

The optimal choice of initial vascular access-arteriovenous fistula (AVF) or graft (AVG)-remains controversial, particularly in patients initiating hemodialysis with a central venous catheter (CVC).

METHODS

In a pragmatic observational study of patients who initiated hemodialysis with a CVC and subsequently received an AVF or AVG, we compared a less selective vascular access strategy of maximizing AVF creation (period 1; 408 patients in 2004 through 2012) with a more selective policy of avoiding AVF creation if failure was likely (period 2; 284 patients in 2013 through 2019). Prespecified end points included frequency of vascular access procedures, access management costs, and duration of catheter dependence. We also compared access outcomes in all patients with an initial AVF or AVG in the two periods.

RESULTS

An initial AVG placement was significantly more common in period 2 (41%) versus period 1 (28%). Frequency of all access procedures per 100 patient-years was significantly higher in patients with an initial AVF than an AVG in period 1 and lower in period 2. Median annual access management costs were significantly higher among patients with AVF ($10,642) versus patients with AVG ($6810) in period 1 but significantly lower in period 2 ($5481 versus $8253, respectively). Years of catheter dependence per 100 patient-years was three-fold higher in patients with AVF versus patients with AVG in period 1 (23.3 versus 8.1, respectively), but only 30% higher in period 2 (20.8 versus 16.0, respectively). When all patients were aggregated, the median annual access management cost was significantly lower in period 2 ($6757) than in period 1 ($9781).

CONCLUSIONS

A more selective approach to AVF placement reduces frequency of vascular access procedures and cost of access management.

Predialysis Vascular Access Placement and Catheter Use at Hemodialysis Initiation

BACKGROUND

Current guidelines encourage placement of an arteriovenous (AV) fistula in patients with advanced CKD to avoid initiation of hemodialysis with a central venous catheter. However, the relative merits of predialysis placement of an AV fistula or graft have been poorly studied.

METHODS

This study included 380 patients (mean age 59±14 years, 73% Black patients, 51% male) from a large academic medical center who underwent predialysis placement of an AV fistula (286) or AV graft (94). The study quantified three end points: time from access placement to initiation of dialysis, likelihood of starting hemodialysis without a catheter, and number of vascular access procedures before dialysis initiation.

RESULTS

The eGFR at access surgery was <10, 10-14, and ≥15 ml/min per 1.73 m 2 in 87 (23%), 179 (47%), and 114 (30%) patients, respectively. The median time from access surgery to hemodialysis initiation was 69, 156, and 429 days in patients with an eGFR of <10, 10-14, and ≥15 ml/min per 1.73 m 2 , respectively ( P < 0.001). Hemodialysis was initiated within 2 years of access surgery in 298 (78%) of the patients. Catheter-free hemodialysis initiation was higher in patients with an AV graft versus an AV fistula when the eGFR was <10 ml/min per 1.73 m 2 (88% versus 43%; odds ratio [OR], 9.10 [95% confidence interval, 2.74 to 26.4]) and when the eGFR was 10-14 ml/min per 1.73 m 2 (88% versus 54%; OR, 6.05 [2.35 to 15.0]) but similar when the eGFR was ≥15 ml/min per 1.73 m 2 (90% versus 75%; OR, 3.00 [0.48 to 34.9]). Patients undergoing an AV fistula were more likely to undergo an angioplasty (11% versus 0%, P < 0.001), surgical access revision (26% versus 8%, P < 0.001), a second access placement (16% versus 6%, P = 0.02), and a catheter insertion (32% versus 11%, P < 0.001).

CONCLUSIONS

Among patients with CKD undergoing vascular access surgery when their eGFR was <15 ml/min per 1.73 m 2 , catheter use at dialysis initiation was much less likely when an AV graft, rather than an AV fistula, was placed.

A Novel Model of Balloon Angioplasty Injury in Rat Arteriovenous Fistula

BACKGROUND

There are very few animal models of balloon angioplasty injury in arteriovenous fistula (AVF), hindering insight into the pathophysiologic processes following angioplasty in AVF. The objective of the study was to develop and characterize a rat model of AVF angioplasty injury.

METHODS

Balloon angioplasty in 12- to 16-week-old Sprague-Dawley rats was performed at the arteriovenous anastomosis 14 days post-AVF creation with a 2F Fogarty balloon catheter. Morphometry and protein expression of endothelial nitric oxide synthase (eNOS), monocyte-chemoattractant protein-1 (MCP-1), alpha-smooth muscle actin (α-SMA), CD68 (macrophage marker), and collagen expression in AVFs with and without angioplasty were assessed.

RESULTS

In AVFs with angioplasty versus without angioplasty: (1) angioplasty increased AVF-vein and artery intimal hyperplasia, (2) angioplasty decreased eNOS protein expression in AVF-vein and artery at 21 days post-AVF creation and remained decreased in the AVF-vein angioplasty group at 35 days, (3) angioplasty increased AVF-vein and artery α-SMA expression within the intimal region at 35 days, (4) angioplasty increased the expression of AVF-vein MCP-1 at 21 days and CD68 at 21 and 35 days, and (5) angioplasty increased AVF-vein and artery collagen expression at 35 days.

CONCLUSION

Our findings describe a reproducible rat model to better understand the pathophysiologic mechanisms that ensue following AVF angioplasty.

Feasibility of Creation of an Endovascular Arteriovenous Fistula in Patients Undergoing Preoperative Vascular Mapping

Background

The first endovascular arteriovenous fistula (endoAVF) device (WavelinQ), a novel percutaneous technique of AVF creation, was approved by the Food and Drug Administration in 2018 and has been placed in a small number of United States patients on hemodialysis. It is unknown how often patients with advanced CKD have vascular anatomy suitable for WavelinQ creation. The goal of this study was to determine the proportion of patients with vascular anatomy suitable for WavelinQ creation and to assess patient characteristics associated with such suitability.

Methods

All patients referred for vascular access placement at a large academic medical center underwent standardized preoperative sonographic vascular mapping to assess suitability for an AVF. During a 2-year period (March 2019 to March 2021), we assessed the suitability of the vessels for creation of WavelinQ. We then compared the demographic characteristics, comorbidities, and vascular mapping measurements between patients who were or were not suitable for WavelinQ.

Results

During the study period, 437 patients underwent vessel mapping. Of these, 51% of patients were eligible for a surgical AVF, and 32% were eligible for a WavelinQ AVF; 63% of those suitable for a surgical AVF were also suitable for a WavelinQ AVF. Patients with a vascular anatomy suitable for WavelinQ were younger (age 55±15 versus 60±14 years, P=0.01) but similar in sex, race, diabetes, hypertension, coronary artery disease, and peripheral artery disease.

Conclusions

Among patients with CKD with vascular anatomy suitable for a surgical AVF, 63% are also suitable for a WavelinQ endoAVF. Older patients are less frequently suitable for WavelinQ.

Fatal superior vena cava rupture complicating dialysis catheter exchange

Central vein stenosis (CVS) is a common and challenging complication in hemodialysis patients with chronic central venous catheters (CVCs). CVS often remains asymptomatic and is discovered incidentally during follow-up imaging. CVS symptoms include arm swelling, venous hypertension, impaired dialysis flow rates, and development of collateral veins. However, these symptoms can be nonspecific and overlap with other conditions, making the diagnosis challenging. Timely recognition and appropriate intervention are crucial to prevent complications and optimize patient outcomes. Diagnostic tools commonly used include duplex ultrasonography and venography to assess the degree and location of stenosis. Management strategies for CVS encompass a multidisciplinary approach involving nephrologists, interventional radiologists, and vascular surgeons. Initial conservative measures may include anticoagulation therapy, along with pharmacological interventions such as antiplatelet agents and thrombolytics. The endovascular approach is the first line for managing CVS by using balloon angioplasty either alone or in combination with stent placement, but CVS typically recurs frequently, requiring repeated interventions with an increased risk of complications. Additionally, alternative vascular access options such as arteriovenous fistulas or grafts may be considered. In this report, we describe a case of a 25-year-old woman who presented with an extensive history of multiple dialysis access failure for left internal jugular vein central venous tunneled catheter exchange. The procedure was complicated by a fatal superior vena cava rupture likely related to the dislodgment of the guidewire causing perforation into the pericardium space with subsequent cardiopulmonary collapse. The post-mortem autopsy showed severe organized stenosis of SVC and transmural defect above the SVC/atrial junction.

Pickering syndrome in a patient with a single kidney: role of renal artery stenting

Renal artery stenosis (RAS) is associated with hypertension and high mortality rates. With its prevalence and associated risk of death, it is important to screen for patients displaying symptoms of RAS. RAS has a wide spectrum of clinical manifestations and is usually resistant to medical therapy. Of these clinical manifestations is Pickering syndrome which is characterized by bilateral renal arterial occlusion inflow lesions, flash pulmonary edema, acute kidney injury, and hypertensive emergencies in the setting of a preserved left ventricle function. Stenting techniques have been used extensively to treat symptomatic renal artery stenosis with excellent primary patency rate, however have failed to demonstrate a long-term benefit over the optimal medical management alone in randomized trials. However, accumulating evidence suggests that stenting is justified in specific patient subgroups that have severe occlusive renal artery stenoses with significant clinical sequelae, including flash pulmonary edema, acute ischemic kidney injury, and uncontrolled hypertension. In this report we discuss the case of a 32-year-old male who presented to our center with recurrent flash pulmonary edema and hypertensive emergency and was found to have RAS, which responded well to renal artery stenting. In conclusion, correcting the renal arterial inflow stenosis is beneficial and warranted in selective clinical scenarios.

Dialysis access-associated steal syndrome with percutaneous endovascular arteriovenous fistula creation

Background

Dialysis access-associated steal syndrome (DASS) is an infrequent complication after hemodialysis access creation. Clinical symptoms depend on the degree of steal. Percutaneous arteriovenous fistula creation offers a minimally invasive alternative to surgical creation, though complications have been reported. The following presents the first described case of DASS after percutaneous endovascular arteriovenous fistula creation, and discusses risk factors and management.

Case Presentation

Our case is that of a 27-year-old male with end stage renal disease due to congenital renal dysplasia, who underwent left percutaneous arteriovenous fistula creation for initiation of dialysis. Two months after the procedure the patient complained of coldness, pain, tingling, and numbness in the left arm during dialysis, concerning for steal syndrome. The patient subsequently underwent brachial artery angiogram, which showed minimal antegrade flow through the ulnar and interosseous arteries towards the hand, and a focal, severe stenosis in the distal ulnar artery. Angioplasty of the stenosis was performed, though steal symptoms continued.

Conclusions

DASS, though rare, can be seen with percutaneous arteriovenous fistula creation. Identification of the risk factors prior to creation can help avoid this complication. Management is largely guided by clinical presentation. As long as there is adequate collateral supply to the extremity, single vessel occlusion is not a contraindication to percutaneous arteriovenous fistula creation with the use of WavelinQ technology. Careful patient selection with pre-creation angiogram may reduce the risk of symptomatic steal.

Value of Immediate Post-Kidney Biopsy Ultrasound in Excluding Late Hemorrhagic Complications

BACKGROUND

Hemorrhage is the most serious potential complication of percutaneous kidney biopsy. Patients are typically observed for at least 6-8 hours after a kidney biopsy, with serial measurements of vital signs and hemoglobin to monitor for major hemorrhage. This study assessed whether an immediate postbiopsy ultrasound can reliably exclude delayed major hemorrhage.

METHODS

We retrospectively evaluated the clinical outcomes in 147 patients undergoing an outpatient native kidney biopsy with an 18-gauge needle at a large medical center during a 2.5-year period (January 2017 to June 2019). All patients underwent a standardized postbiopsy ultrasound to assess for active extravasation of blood. We extracted from the medical records vital signs and hemoglobin values obtained before the biopsy and at 2, 4, and 6 hours after the procedure. We ascertained whether any patients with a negative postbiopsy ultrasound developed a delayed major hemorrhage.

RESULTS

Each patient underwent two or three biopsy passes. The mean patient age was 48±17 years, 49% were female, 37% were black, 53% had hypertension, and 16% had diabetes. Of the 142 patients without evidence of active extravasation on ultrasound, the BP, heart rate, and hemoglobin remained stable during 6 hours of observation. All were discharged after 6 hours, and none had a late bleeding complication.

CONCLUSIONS

If the immediate postkidney biopsy ultrasound does not show active bleeding, the patient is extremely unlikely to develop a late major hemorrhagic complication (negative predictive value, 100%). Such patients can be discharged home safely after a 2-hour observation, thereby simplifying their management.

Hemodialysis Access: US for Preprocedural Mapping and Evaluation of Maturity and Access Dysfunction

Patients with kidney failure require kidney replacement therapy. While renal transplantation remains the treatment of choice for kidney failure, renal replacement therapy with hemodialysis may be required owing to the limited availability and length of time patients may wait for allografts or for patients ineligible for transplant owing to advanced age or comorbidities. The ideal hemodialysis access should provide complication-free dialysis by creating a direct connection between an artery and vein with adequate blood flow that can be reliably and easily accessed percutaneously several times a week. Surgical arteriovenous fistulas and grafts are commonly created for hemodialysis access, with newer techniques that involve the use of minimally invasive endovascular approaches. The emphasis on proactive planning for the placement, protection, and preservation of the next vascular access before the current one fails has increased the use of US for preoperative mapping and monitoring of complications for potential interventions. Preoperative US of the extremity vasculature helps assess anatomic suitability before vascular access creation, increasing the rates of successful maturation. A US mapping protocol ensures reliable measurements and clear communication of anatomic variants that may alter surgical planning. Postoperative imaging helps assess fistula maturation before cannulation for dialysis and evaluates for early and late complications associated with arteriovenous access. Clinical and US findings can suggest developing stenosis that may progress to thrombosis and loss of access function, which can be treated with percutaneous vascular interventions to preserve access patency. Vascular access steal, aneurysms and pseudoaneurysms, and fluid collections are other complications amenable to US evaluation. ©RSNA, 2023 Supplemental material is available for this article. Test Your Knowledge questions for this article are available through the Online Learning Center.