Percutaneous Device for Dialysis Access 'a Significant Advance'

A new device for the percutaneous creation of an arteriovenous fistula (AVF) for hemodialysis access in patients with kidney disease has excellent cumulative patency rates out to 2 years and is associated with high levels of patient satisfaction, new research indicates.

"The optimal vascular access for dialysis is a clinically functional AVF," Gerald Beathard, MD, PhD, University of Texas Medical Branch, Galveston, and colleagues explain in their article published online in the Journal of Vascular Access.

"Unfortunately, a large percentage of surgically created AVFs experience either primary failure or failure to mature...[so] there is a need for innovation in AVF creation," they observe. "This study demonstrates that using a novel [percutaneous] technique to create the anastomosis...avoids surgical trauma and vessel manipulation," they add.

And they elaborate, the method used — a proximal radial artery (PRA)-AVF — has the advantage of low complication rates and more durable patency potential compared with other types of AVFs.

The device used in the study, the Ellipsys Vascular Access System (Avenu Medical), was approved by the Food and Drug Administration in 2018 and approximately 1000 patients worldwide have undergone the percutaneous procedure since the device became globally available.

First 2-Year Data for Any Endovascular Fistula Procedure

Until recently, the only way to create an AVF was an open surgical procedure. Percutaneous options transform a complex surgery into a minimally invasive procedure that can be performed in a hospital outpatient setting or ambulatory surgical center, the researchers say.

The current multicenter study involved 105 patients who had had their fistulas created using the Ellipsys Vascular Access System at five vascular access programs in the United States.

"This is a thermal resistance device consisting of a single venous access catheter," the investigators explain.

Using either local or regional anesthesia plus conscious sedation, the procedure is carried out percutaneously during which the catheter is introduced over a guidewire through a single cannulation of one of two veins at the elbow.

The device is then advanced through the deep communicating vein and on into the adjacent PRA. As the authors explain, the creation of an anastomosis between these two veins using the endovascular approach avoids vessel mobilization, rotation of vein to artery, and chances of technical misadventure.

An anastomosis is then created by applying pressure and heat from the device to fuse the deep communicating vein and the adjacent PRA.

Following the creation of the anastomosis, the veins are dilated using a small angioplasty balloon, at which point the intervention is complete.

The procedure is done using only ultrasound guidance and requires no exposure to radiation.

"We knew fistulas created with Ellipsys functioned well in the beginning, but patients wanted to know how long their access sites would last," said Terry Litchfield, MPH, a study co-author and president of Access Solutions, a patient advocacy consulting service in the dialysis industry.

"Our goal was to see how many still worked after 2 years while capturing patients' opinions on this innovative procedure," she said in a press release issued by Access Solutions.

Defining a "clinically functional AVF" as an access capable of supporting two-needle dialysis according to the patient's dialysis prescription, access failure leading to loss of access occurred in eight patients during the 2-year observational interval.

Some 17% of the cohort died over the course of observation but the AVF was still functioning at the time of their death, with a mean duration of function of 353 days.

Approximately 6% of the cohort also underwent kidney transplantation; here again, the endovascular AVF was also functioning at the time of transplantation at a mean duration of 201 days.

The study marks the first published 2-year data for any endovascular fistula procedure, and the cumulative patency rates for the total cohort were impressive, say the researchers.

Nearly 92% of the fistulas continued to function 2 years after the Ellipsys procedure. In contrast, less than two thirds of surgically created fistulas are still functional after 2 years.

Table. Cumulative Patency Rates of the Endovascular AVF

Month	3	6	9	12	15	18	21	24
Patency Rate, %	96.1	96.1	95.0	92.8	92.8	92.8	91.6	91.6

Patient Satisfaction Was High: "I Had No Surgery, No Stitches"

Patients who underwent the endovascular technique were subsequently mailed a survey; 39% of them responded.

"Patient responses indicated a high level of satisfaction with the procedure," the investigators report.

For example, the absence of pain experienced during the procedure was deemed "excellent" or "very good" by 95% of respondents.

One respondent, who underwent the Ellipsys procedure in 2015 and used the fistula for dialysis until her kidney transplant in 2018, appreciated the fact that she was left with no scars on her arm, unlike patients who undergo a surgically created anastomosis, which leaves a scar.

"I had no surgery — no stitches, no cuts, and I wasn't put to sleep. I left with a band-aid and went about my day," she noted.

Durability of Endovascular Access Is "Striking"

Commenting further on the findings, Beathard noted that the difference in durability between the fistulas created with the novel endovascular device and those that are surgically created is "striking."

For example, 39% of AVFs placed over a period of about 2 years in the United States were either primary surgical or maturation failures, according to an annual report from the US Renal Data System.

"Many of these early AVF failures are ultimately salvaged but frequently require more than one procedure to become clinically usable," the authors observe.

"The ability to quickly and easily create a fistula that will last a long time, without surgical trauma or the need for additional procedures, could represent a significant advance in dialysis patient care," Beathard concluded in the press release from Access Solutions.

J Vasc Access. Published online September 28, 2019. Full text

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