Advancements in Testing Prosthetic Heart Valves

Improved hydrodynamic testing of prosthetic heart valves and conduits to simplify testing and provide more accurate results. The testing system involves a single apparatus that can test both forward flow pressure drop and backward flow leakage in a continuous flow environment. The apparatus includes a test chamber with a prosthetic valve mounted within it and sensors to measure flow rate, pressure, and leakage. A control system automatically adjusts flow conditions to specified levels and records the performance metrics.

A testing apparatus for prosthetic devices like drug-eluting stents to accurately simulate the forces they experience in the body. The apparatus has a movable shaft to apply tension and compression to the device while fluid flows through it. This allows testing of factors like particle shedding rate under dynamic force conditions. It also has features like flow lines, particle counters, and filters downstream to analyze the device's performance. The device can be mounted with tensioning elements to preload it before testing.

A method for testing the flexibility of prosthetic heart valve leaflets to facilitate proper functioning of the valves. The method involves draping multiple leaflets over a series of bars and capturing an image of them. Computer analysis of the image is used to assign flexibility values to the leaflets. The leaflets are then categorized based on their flexibility values. By sorting and grouping the leaflets based on flexibility, it allows optimal matching of flexible leaflets for sewing together in prosthetic valves to minimize regurgitation.

Testing apparatus for prosthetic heart valves that can accurately measure flow properties, leaflet coaptation, and leakage of prosthetic valves under physiological conditions using a simplified design. The apparatus flows test fluid through the valve in both directions when open and applies pressure profiles when closed. Images are captured to analyze leaflet coaptment. A calibration device with spaced walls helps correct for optical distortion in the images.

Method for testing fatigue to fracture of implantable medical devices like stents by subjecting them to enhanced radial compression and expansion beyond physiological limits to determine endurance limits. The method involves using mock vessels with higher or lower compliance than normal, deploying the implant in them, and cyclically expanding them using pressurized fluid while monitoring with high speed cameras to see when failure occurs. This allows testing beyond physiological limits to find the device's true endurance limit.

Prosthetic heart valve with integrated sensors for monitoring valve performance after implantation. The sensors are designed to attach securely to the stent of the valve in a collapsed state for delivery. The sensors can measure physiological data like pressures and flows to monitor valve function. The sensors have features like finger channels or chamfered heads to attach to the valve stent struts. This allows accurate monitoring of prosthetic valve performance in vivo and helps diagnose issues like leakage or calcification.

Method for optimizing placement of mitral valve prostheses using computer modeling and imaging to predict blood flow obstruction. The method involves acquiring images of the heart anatomy showing the mitral valve and left ventricular outflow tract (LVOT). Positions for the prosthetic valve are designated in the images. Using modeling, the obstruction of blood flow through the LVOT is predicted for each position. This helps find the optimal placement to minimize obstruction.

Accelerated life testing system for valves like heart valves to simulate and accelerate the aging process for durability testing. The system has a chamber with a valve holder, fluid displacement member, and actuator. The chamber has return flow orifices connecting the proximal and distal spaces. A camera, lights, and pressure sensors monitor the valve during cycling. The chamber can tilt, and the lights illuminate at rate correlated to actuation. The system adjusts valve area based on indication from the camera, and the lights are controlled to match valve cycling rate.

Apparatus and methods for testing replacement heart valves that provides reliable and accurate testing while complying with standards like ISO 5840. The testing system uses a non-sinusoidal motion for the fluid impeller to drive the flow through the valve, which mimics more realistic physiological conditions. It also has a controllable bypass valve to limit reverse pressures applied to the valve. A pressure control system with compliance devices upstream and downstream regulates pressures. This allows accurate accelerated testing without excess spikes or reverse pressure failures.

Endovascularly delivering a replacement heart valve to a vicinity of a diseased valve, assessing the operation and location of the unexpanded valve before fully expanding it, and repositioning if necessary. This allows real-time feedback and adjustment during implantation. The valve expands partially first to enable evaluation of factors like blood flow and leakage.

Testing inflatable endovascular prostheses like stent grafts for leaks after loading onto delivery systems to catch defects before deployment. The inflatable portion is filled with sterile material and pressurized while on the delivery catheter. Leaks are inspected before removing the fill material. This allows finding and addressing issues that may arise during prosthesis loading and packaging before sterilization and shipping.

Simulating prosthetic heart valves using computer modeling to accurately predict valve performance and durability without physical prototypes. The method involves creating 3D models of the valve leaflets and frame using finite element analysis (FEA). The leaflets are simulated by starting from 2D drawings and wrapping them around the frame with edge constraints. This allows precise 3D geometry based on the leaflet shape and assembly process. The simulated valve is then tested by applying fluid cycles to monitor stresses.

Compact and portable testing system for prosthetic heart valves that allows both pulse duplicator testing and accelerated wear testing in a single device. The system uses a solid housing with a main channel dividing into two paths at a bifurcation. One path simulates heart pulses, the other accelerated flow for wear testing. A chamber with a reciprocating piston mimics heart pumping. Valves can be positioned in the paths to test durability or simulated pulse response.

A method and apparatus for testing paravalvular leakage around prosthetic heart valves to evaluate the integrity of valve fixation. The testing involves mounting the sewing rings of prosthetic heart valves onto an annular member in a chamber, pumping pulsatile flow through the valves, and collecting drips below the chamber to measure paravalvular leakage. This provides a direct and quantifiable method to assess paravalvular leakage around prosthetic heart valves.

Testing method and apparatus for stents used in prosthetic heart valves to accurately evaluate their fatigue properties. The testing involves cycling a stented structure with a flexible membrane connected to the stent. The membrane blocks flow when pressure is applied in the backward direction. This better approximates the in vivo loading on the stent. The membrane doesn't fully open in the forward direction. This allows higher cycling frequencies than a full opening valve. The apparatus has a pump to cycle the stented structure and a chamber to contain the fluid.