Elastic Flow-Control Grafts
VascX is developing elastic flow-control grafts as part of its patented platform for hemodialysis access. The concept is intended to preserve dialysis performance while reducing excessive AV graft flow and the cardiac burden that can accompany it.
The arteriovenous graft has been a workhorse of hemodialysis access for decades. It is reliable, technically straightforward to place, and gives clinicians a predictable conduit for dialysis. It also creates a low-resistance pathway between artery and vein that drives a continuous high-flow circuit through the heart — and that continuous flow is the variable VascX's elastic flow-control grafts are designed to address.
What is an elastic flow-control graft?
An elastic flow-control graft is a dialysis access graft whose internal geometry is designed to limit excessive access flow while still supporting dialysis. The "elastic" part of the description matters: the graft is intended to flex enough to accept standard access management — including cannulation needles, balloon-assisted procedures, and thrombectomy devices — and to return to its calibrated flow-control profile after those interventions.
Conceptually, this is the opposite of a stent-graft optimized for maximum patency at maximum flow. The design question is not "how much flow can the device deliver?" but "how much flow does dialysis actually need, and how much continuous extra flow can the patient's heart safely tolerate?"
Why AV graft flow matters
AV grafts are an important hemodialysis access option, especially for patients whose veins are not suitable for a fistula. But, like fistulas, AV grafts create a sustained low-resistance circuit between artery and vein, increasing venous return and cardiac output demand around the clock — not just during dialysis sessions.
Excessive AV graft flow has been associated with cardiac burden in some patients, including cardiac remodeling, pulmonary hypertension, and high-output heart failure in susceptible patients. For a deeper look at the underlying problem, see high-flow dialysis access, high-flow AV graft, and high-output heart failure and dialysis access.
Flow-control AV graft design
A flow-control AV graft is built around the recognition that the dialysis machine and the heart have different flow needs. The machine pulls a few hundred milliliters per minute through the dialyzer during a treatment session; everything beyond that is continuous extra flow the heart has to support. A flow-control AV graft is designed to deliver the flow needed during dialysis while limiting that continuous excess.
VascX's elastic flow-control grafts implement this design through a calibrated geometry intended to limit access flow without occluding the access. The graft is designed to be placed using standard surgical workflows for AV graft creation, so the practical change for the implanting surgeon is intended to be minimal.
Preserving dialysis adequacy
Reducing access flow only matters clinically if dialysis adequacy is preserved. A flow-control AV graft that compromised the patient's ability to receive effective hemodialysis would not be a meaningful improvement. The design intent of VascX's elastic flow-control grafts is to deliver the dialysis-machine flow needed during treatment while limiting continuous between-session access flow.
Whether a given device achieves this two-sided goal in practice is an empirical question to be answered by preclinical and clinical evidence. VascX's elastic flow-control grafts are investigational and have not yet been demonstrated in clinical use; the company makes no claim that they are proven to preserve dialysis adequacy or to reduce cardiac burden.
Cannulation and intervention compatibility
An AV graft has to be cannulated for every dialysis treatment and may need standard interventions over its lifespan. Thrombectomy in particular — the procedure used to clear clot and restore access patency — is part of the routine clinical management of grafts. A flow-control device whose geometry could not accommodate standard cannulation or thrombectomy would shift the clinical cost onto the patient and the access team.
VascX's elastic flow-control grafts are designed to support standard cannulation patterns and to accept standard interventions, including thrombectomy. The elasticity of the device is what enables this: the graft is intended to flex to accommodate a thrombectomy catheter and then return to its calibrated profile afterward, so flow-control is preserved without imposing new procedural constraints.
Part of the VascX patented platform
VascX's elastic flow-control grafts are a flow-control AV graft built around the realities of clinical access management. The graft is designed to preserve dialysis-machine performance during treatment and to accommodate the routine procedures that any AV graft needs to live with — cannulation for every dialysis session, and thrombectomy or other revisions as the access ages — while limiting continuous high-flow burden between sessions. At the Vascular Access Society of the Americas (VASA), Dr. John Ross discussed the "VascX patented platform" and presented images of VascX's "elastic flow-control grafts" and "elastic flow-control stents," the graft for new access creation where flow-control can be built in from the start, the stent for existing high-flow AV access where flow-control is introduced into the circuit.
For more on the broader category and the VASA discussion, see flow-control dialysis access and the press release VascX flow-control platform highlighted at VASA.
Frequently asked questions
What is an elastic flow-control graft?
An elastic flow-control graft is an arteriovenous graft for hemodialysis access whose geometry is designed to limit excessive access flow while preserving dialysis-machine performance. The elastic element is what distinguishes it: the graft is intended to accept standard interventions, such as thrombectomy, and return to its calibrated flow-control profile afterward. VascX's elastic flow-control grafts are investigational and are not cleared or approved by the U.S. Food and Drug Administration.
What is a flow-control AV graft?
A flow-control AV graft is an arteriovenous graft designed with built-in geometry that limits the volume of blood flowing through it. Rather than relying on a separate access flow reduction procedure later, the graft itself is intended to deliver dialysis-grade flow during treatment while limiting the continuous high-flow burden on the heart between sessions. VascX's elastic flow-control grafts are an investigational example of this approach.
Why does AV graft flow matter?
AV graft flow is the volume of blood moving continuously through the dialysis access graft. The dialysis machine needs only a portion of that flow during treatment; the rest is continuous extra work for the heart. Excessive AV graft flow is associated with cardiac burden, including cardiac remodeling, pulmonary hypertension, and high-output heart failure in susceptible patients. Reducing excessive AV graft flow without compromising dialysis adequacy is the underlying goal of flow-control AV graft design.
Can a flow-control graft preserve dialysis adequacy?
Flow-control graft designs are intended to preserve dialysis adequacy by delivering sufficient flow through the dialyzer during treatment while limiting continuous access flow between sessions. The dialysis machine typically requires several hundred milliliters per minute through the dialyzer; the much higher continuous access flow seen in many AV grafts exceeds what the machine needs. VascX's elastic flow-control grafts are designed around this distinction, but they are investigational and have not yet been demonstrated to preserve dialysis adequacy in clinical use.
Why do cannulation and thrombectomy compatibility matter?
An AV graft has to be cannulated for every dialysis session and may require thrombectomy or other interventions over its lifespan. A flow-control graft that interferes with cannulation or that cannot accommodate thrombectomy would impose a clinical cost in exchange for the flow benefit. VascX's elastic flow-control grafts are designed to support standard cannulation patterns and to accept standard interventions, including thrombectomy, returning to their calibrated profile afterward.
How does this relate to high-flow dialysis access?
High-flow dialysis access refers to AV fistulas and AV grafts that deliver blood flow well above what is needed for dialysis. The continuous extra flow is associated with cardiac burden and other complications in susceptible patients. Elastic flow-control grafts are designed to address the high-flow problem from the start, rather than after complications appear, by building flow-control into the graft itself.
Are VascX products FDA-cleared?
VascX products are currently in development and are not yet cleared or approved by the U.S. Food and Drug Administration.