Announcement of the Results

Manners Technology, leveraging its "Computational Fluid Dynamics (CFD) driven design platform," successfully launched the world's first AVF needle based on multi-objective topology optimization - "Hemosphere™ Blood Flow Optimization Needle." This needle abandons the traditional single end-hole design and adopts a "composite helical side-hole array" and a "gradually varying flow velocity conical inner cavity." Fluid dynamics simulations and in vitro experiments confirmed that this design can reduce the turbulent kinetic energy of blood in the needle tube by 52% and the peak effective shear stress by 40%. In a one-year multicenter clinical study, patients using this needle saw an average increase of 5% in dialysis adequacy (Kt/V) per treatment session, and the rate of intimal hyperplasia at the puncture site significantly decreased.

Research and Development Background and Challenges

The "sharp conical tube body + single-hole at the end" design of the traditional AVF needle is derived from the common injection needle and does not fully consider the extreme fluid environment of hemodialysis, which leads to many clinical problems:

Suction of the wall and poor blood flow: Under a high negative pressure of 200-400 mL/min, the end-hole needle is prone to "suck" the vascular inner wall or the inner membrane of the arteriovenous fistula, resulting in blood flow interruption, frequent alarms, and damage to the blood vessel.

High shear force and hemolysis: When the blood flow suddenly contracts and enters the narrow needle hole, it generates extremely high shear force, damaging red blood cells (hemolysis) and increasing the difficulty of managing anemia in patients.

Blood flow dead zones and coagulation: The connection point between the needle base and the needle tube, as well as the rough areas on the inner wall of the needle tube, are prone to form blood flow stagnation zones, promoting platelet aggregation and the formation of tiny blood clots, which have a risk of embolism if detached.

Inaccurate puncture positioning: The geometric shape of the traditional needle tip provides unclear feedback on the puncture depth, easily leading to deep puncture (stimulating the posterior wall of the blood vessel) or shallow puncture (high risk of bleeding).

Core Technological Innovation

The manufacturer carried out a revolutionary geometric reconfiguration based on CFD simulation as the core.

Composite helical side-hole array design: In a specific area behind the needle tip, through 5-axis laser precision cutting, 2-3 groups of side holes arranged in a spiral pattern are manufactured. The hole diameters and distribution have been optimized through CFD to ensure that at any needle tip angle, there is always a part of the side holes in the optimal blood flow position, fundamentally eliminating the "suction wall" phenomenon.

Gradual flow velocity conical inner cavity: The inner cavity of the needle tube is not of uniform diameter; instead, it is designed as slightly thicker at the entrance and gradually narrower towards the tail end with a streamlined conical shape. This design conforms to the ideal model of fluid acceleration movement in the pipeline and can smoothly guide the blood flow, avoiding the generation of intense vortices and sudden pressure drops at the entrance.

"Double inclined plane echo" needle tip geometry: The innovative needle tip edge geometry adopts asymmetric double inclined plane grinding. Its functions are: first, to reduce the puncture resistance; second, when the needle tip penetrates different layers of the blood vessel wall, it can provide differentiated tactile feedback to the operator, like an ultrasound echo, indicating the puncture depth. At the same time, the inside of the needle tip is pre-formed with tiny blood flow guiding inclined planes, so that the blood is directed to the side holes as soon as it enters the needle tip, reducing end turbulence.

Mechanism of Action

The innovative geometric design functions by guiding and optimizing the blood flow state:

The spiral side-hole array achieves "multiple entry points and distributed" blood collection. This is equivalent to converting a single-point high-flow suction into multiple small-flow regional suction, significantly reducing the local negative pressure peak, thereby eliminating the adhesion force of the needle hole on the vascular wall (Bernoulli effect), protecting the fragile inner fistula endothelium.

The conical inner cavity follows the reverse application of the Venturi effect. Blood flow enters from a thicker inlet and then gradually accelerates smoothly, converting the flow energy more effectively into pressure energy, maintaining a more stable pressure gradient within the tube, reducing energy loss and turbulence caused by sudden changes in cross-section, and thus lowering the overall shear force level.

The "double inclined plane echo" needle tip, during puncture, the first inclined plane penetrates the skin and subcutaneous tissue, and the second inclined plane at a specific angle generates a perceptible resistance change when penetrating the tough vascular wall, clearly indicating to the operator "in the vascular cavity," and then the blood flow guiding inclined plane immediately introduces the blood into the side hole, achieving "blood flow upon puncture."

Efficacy Verification

The "Hemosphere™ Needle" has been fully validated in simulation circulation systems and clinical trials.

CFD simulation and particle image velocimetry: The CFD simulation shows that at a flow rate of 350 mL/min, the size of the main vortex core in the new syringe is reduced by 80%. The visualized flow field through the particle image velocimetry technology confirms that the blood flow is in a stable laminar state passing through the side hole array.

In vitro blood injury index test: Using fresh human blood in a simulated circulation for 4 hours, plasma free hemoglobin was detected. The hemolysis index (HI) of the new needle was 45% lower than that of the traditional needle.

Clinical multicenter study: 200 stable hemodialysis patients were included. They were cross-compared and used the traditional needle and the new needle for 3 months each. The results showed that during the use of the new needle: ① The number of times the hemodialysis machine was interrupted for "low arterial pressure" alarms decreased by 70%; ② The fatigue score after dialysis of the patients significantly improved; ③ The average monthly dosage of erythropoietin (EPO) decreased by 8%; ④ The increase in the intima thickness of the puncture point vessels detected by ultrasound decreased by 30%.

Research and Development Strategy and Philosophy

The R&D philosophy of Manners Technology in this field is "Let fluid dynamics guide the design, rather than let manufacturing processes limit the design." They have established a "Digital Twin Laboratory," first conducting high-fidelity CFD simulations on dozens of needle tip and cavity geometric models, selecting the 1-2 models with the best fluid performance, and then using advanced 5-axis laser technology to manufacture them. This "simulation-driven design" model transforms the traditional "design - prototyping - testing" long-cycle iteration into an efficient "virtual screening - precise manufacturing - clinical validation." Its core strategy is to eliminate the biological causes of hemodialysis complications (such as shear force and turbulence) at the physical level through the design of the equipment.

Future Outlook

The future design of AVF needles will deeply integrate "patient-specific modeling" and "adaptive fluid control." Manufacturers are exploring three-dimensional reconstruction and personalized blood flow simulation based on CTAs or ultrasound images of the patient's arteriovenous fistula vessels, in order to customize the optimal side hole position and needle tip angle for specific vascular shapes (such as larger curvature, aneurysmal dilation). A more intelligent direction is "variable geometry needles": the needle tube uses intelligent materials, and its side hole opening area or needle tip shape can be finely adjusted when powered on or at specific temperatures to adapt to the hemodynamic requirements at different stages of the treatment (such as the initial high resistance period of blood drainage, and the stable treatment period). In the long run, AVF needles will serve as a key "sensor + regulator," integrated into the intelligent control system of the hemodialysis machine, to achieve real-time, adaptive, and personalized management of extracorporeal circulation.