Novel Endovascular Procedure for Hemodialysis Access
March 09, 2020
University Hospitals among first in Ohio to utilize innovative technique
Innovations in Cardiovascular Medicine & Surgery | Winter 2020
A novel percutaneous access procedure that utilizes radio frequency (RF) energy is enabling surgeons to create an endovascular arteriovenous fistula (endoAVF).
“There are increasing numbers of patients with kidney failure who need hemodialysis,” says Christopher Smith, MD, vascular surgeon at University Hospitals Harrington Heart & Vascular Institute and Assistant Professor of Surgery at Case Western Reserve University School of Medicine. “Prior to this, open surgery has been the standard for creating an arteriovenous fistula or shunt for reliable cannulation.”
A high flow volume in the superficial vein is necessary to successfully dialyze a patient. “We are able to steal blood flow from an artery with relative impunity and route it through the appropriate vein to achieve adequate arterialization for hemodialysis,” says Dr. Smith. The WavelinQ™ 4F EndoAVF System, manufactured by Bard Medical, offers a significant advancement in fistula creation for select patients.
Benefits of minimally invasive endoAVF include negligible incisional pain, a quicker return to normal activities and increased options for vascular access during cannulation. “We have also observed that the endovascular circuit seems to require less flow volume than a surgical fistula,” says Dr. Smith. “This is not a panacea for creation of hemodialysis access, but it is a significant advancement for appropriate patients.”
HOW IT WORKS
The procedure involves inserting a pair of 4 French (4F) hydrophilic-coated catheters over guide wires through a small incision in the arm into a concomitant artery-vein pair. When the two catheters are positioned adjacent to each other under fluoroscopy, magnets within the catheters align and connect. Then, a 0.7-second RF energy burst fuses a channel between the two blood vessels. “We need to have good apposition in order to achieve successful cauterization of the fistula,” says Dr. Smith. Early data, including the FLEX and NEAT clinical studies of WavelinQ, indicate fewer complications or reinterventions compared with surgical AVF.
Dr. Smith performed the first endoAVF procedure at University Hospitals and one of the first in Ohio. He currently offers the procedure at University Hospitals St. John Medical Center, a Catholic hospital. Two additional sites will soon be available throughout the community:
- Virginia Wong, MD, Program Director of Vascular Surgery at UH Harrington Heart & Vascular Institute and Assistant Professor at the School of Medicine, will be offering endoAVF at University Hospitals Richmond Medical Center, a campus of UH Regional Hospitals.
- Jeffrey Boyko, DO, vascular surgeon at UH Harrington Heart & Vascular Institute and Clinical Assistant Professor of Surgery at the School of Medicine, will be offering endoAVF at University Hospitals Parma Medical Center.
Ultrasound vein mapping is utilized to screen and identify patients as potentially suitable candidates. “Not all anatomy lends itself to this procedure,” says Dr. Smith. “The most important criteria anatomically are sufficient target vessel diameter [≥2.0mm] and existence of an adequate or communicating vein between the deep venous system and the superficial venous system.”
Factors that could preclude a patient from endoAVF include:
- long-term or advanced diabetes
- excess calcification in blood vessels
- significant atherosclerosis
- advanced age
- inadequate blood flow through deep venous system
- chronic thickening or phlebitis in veins
“Ancillary surgical revisions may still be required prior to the fistula being used for dialysis,” says Dr. Smith. “Once the patient is preliminarily approved for the procedure, we move to the interventional radiology suite and shoot a venogram. If that is favorable, we proceed and the catheters are inserted under mild sedation and local anesthetic.”
Next, fluoroscopy confirms that the fistula is in place and that arterialization of the venous system has been achieved. Finally, the surgeon coils or blocks the deep vein system in the lower arm so that blood is preferentially shunted to the superficial system. Post procedure, there is a possibility of bleeding to control, particularly at the arterial puncture site. Typically, patients are ready for hemodialysis in four to six weeks — after the new circuit has experienced significant blood flow.
To contact Dr. Smith for more information, or refer a patient, call 216-553-1439.