Handle Delivery System:Trans-catheter valve therapy has emerged as an alternative to patients who have valvular heart disease and are not candidates for open heart surgery. It provides a less invasive method for delivering a replacement heart valve to the diseased native valve. A prosthetic heart valve is mounted inside a delivery catheter. To deploy the valve, a handle is built onto the proximal end of the catheter.

lThe user interacts with the handle to manipulate the catheter into the correct position, deploy the valve, and finally withdraw the catheter from the patient’s body once the prosthesis is deployed. This project will demonstrate a summarised version of the process I went through for designing the proposed handle concept.

Handle Delivery SystemResearch & Exploration

A thorough research phase was carried out in accordance with a design brief. Aims and objectives were constructed to provide a more extended investigation into the field of study, and a variety of mediums were used to obtain the data. The areas explored can be sub-categorized under the following headings:

AREA BACKGROUND

PRODUCT RESEARCH

USER INTERACTION

Handle Delivery SystemConcept Development

Design specifications derived as a result of both the design brief and the research findings. They were then intended for use with a variety of cardiovascular devices, ranging from stents to replacement heart valves. These specifications created the framework of design parameters for generating early concept ideas.

This early stage of development began with an ideation stage, utilizing brainstroming techniques. Mechanical operations from many different types of products were viewed as inspiration for performing similar tasks and meeting the design specifications.

Handle Delivery SystemConcept Development

Ideas were narrowed down resulting in two very distinct concepts, and development revolved around an amalgamation of both concept ideas. There were many design elements to consider for further development.

1. Reduction in length2. Modular & Universal

Split Shaft

Support Shaft

Threaded Guides

Central Casing

Rotary Cogs& Worm Drives

1. Grip 2. Micro Retract 3. Macro Retract

4. Retract Inner 5. Retract Inner-Most 6. Advance Outer-Most

Handle Delivery SystemTesting & Validation

Physical prototypes were constructed to emulate concept ideas and to explore the performance under a variety of environments. The order of sequence in which the handle would be used in a real case scenario was interpreted, so as to reduce the amount of steps and required wrist movement.

USABILITY TESTING:

Handle Delivery SystemTesting & Validation

Each individual component and mechanism within the assembly was analysed and tested to ensure maximum design efficacy. Test rigs were constructed and Finite Element Analysis (FEA) tests were performed.

MECHANICAL TESTING:

Handle Delivery SystemManufacturing & Assembly

Handle Delivery SystemConcept Refinement

Taking all design elements into account, the proposed handle design was refined so as to offer effective controlability. The final mechanism within the assembly utilizes a series of rotary and linear operations to both deploy, and release the prosthetic replacement heart valve.

The process is as follows:1. Rotate knob clockwise to retract outer-most shaft2. Push knob forward and rotate clockwise to retract inner shaft3. Retract inner-most shaft4. Push knob forward and rotate anti-clockwise to reclose OM shaft

Universal Grip

Isolation Sheath

Shaft Manipulation (macro) Guidewire Entry

Shaft Manipulation (micro)

Inner-most Shaft Manipulation

Handle Delivery SystemConcept Refinement