The depths of valve replacement

Research Analysis Damian Carr

Product Design & Technology0878057

Topics Covered• Introduction• Valve replacement industry• Access sites• CAT lab• Medtronic’s fore take • Subclavian access in other fields• Subclavian trials via Corevalve• Transapical and transfemoral• Direct aortic• Design Stages for Catheters • New Take on FYP• Subclavian/Trans aortic handle needs• Design Plan• Summery

Introduction

» Initial FYP idea: To create a Catheter that delivers a Medtronic Engager valve into an Aortic valve via a subclavian access» Field: Medical Industry» Funding: Medtronic » Project style: Mixed (blue sky/Incremental)

Valve replacement industry• Due to calcified aortic valves• Non invasive• Typical in patients 65+• Survival rate 85%+• 2 forms of valve –Mechanical valves –Tissue valves

Via Engineer Interviews/journals

Access Sites

Via Medtronic Data

CAT Lab

Via Cat lab visit June 2011

Medtronic’s fore take • Currently produce 2 aortic valves - Corevalve and Engager• Cover Transfemoral, Apical and Direct aortic• 3rd largest internal income• Covers 18% of company sales• Implanting since August 1992• In the top 3 companies for aortic replacement

Via journal articles/interview/Online research

Subclavian access in other fieldsAngioplasty’s• 113 patients• Mean age – 63+/- 13 years• 91% success• 3 procedural complications• 1 transient ischemic attack• 1 fatal stroke• 1 arterial thrombosis

Conclusion – Safe and effective, good long term patency. Less arterial punctures, less bloodstream infection

Central venous catheters(jugular vs subclavian• Six trials(2010 cathaters)6 times less arterial punctures

• Three trials(707 cathaters)Less than half bloodstream infection

Via journal articles

Subclavian trials via Corevalve• 6 implantations due to arterial blockage and apical risks • Euro score 28.4%• 100% success post surgery• 89% success after 30 days• 76% recovery in stage 1(first 2 days)

Conclusion: reduced aortic gradient by 5mm immediately after valve replacement, non invasive, requires skin incision, less discomfort than transfemoral

Via journal’s/ Online interview with Neil Moat(leading aortic surgeon)/Case report

Transapical and transfemoral• High risk implantations between 2007-2009• 203 patents, euro score 22%+/-14%, age 81+/-7years • Transapical – 50 cases • For patients who had no femoral access• 30 day survival 91.7%• Death due to 25% valve related, 25% cardiac, 50% non cardiac

•Transfemoral -153 cases•30 day survival 88.8%•Death due to 31% valve related, 13% cardiac 56% non cardiac

Via journals/ Online interview with Neil Moat(leading aortic surgeon)

Direct Aortic» Simular valve oriantation to subclavian» Same access direction» Simular shaft length needed» Covers 2 access points, thorocotomy(splits rib cage down the center)Sternotomy(splits 4th and 5th or 5th and 6th intercostal spaces

in right rib cage» Only at animal trial phase, no implantations to date

Via interviews with Designers/Engineers/Technicians s

Design Stages for Catheters

Phase 0- Research, initial prototypes to prove principal• Background research• Mechanical capability• Travel availability• Tracking capabilityPhase 1- from conceptual design to design freeze

» Capsule development» Shaft development» Mechanical finalisation» Flushing ability» Ergonomic incorporation» Aesthetical finishing

Via interviews with Designers/Engineers/Technicians/Manifacturer

New Take on FYP» New FYP idea: To create a Catheter that delivers

a Medtronic Engager valve into an Aortic valve via a subclavian access and creating a sister version of the handle that can be used for direct aortic access» Field: Medical Industry» Funding: Medtronic » Project style: Mixed (blue sky/Incremental)

Subclavian/Direct Aortic Handle Needs

• Colour• -Must abide by the Medtronic colour

chart

Subclavian/Direct Aortic Handle Needs

• Mechanics• -Must Deploy 2 capsule half’s in 2 different directions using

same directional movement• -Must transfer force effectively and efficiently • -Must be contained inside a handle or shell• -Must not interfere with flushing• -Materials must be medically acceptable• -Must not fail during deployment

Subclavian/Direct Aortic Handle Needs

• Flushing• -Must flush up the inner shaft• -Must flush the capsule leaving no air bubbles• -Must flush between the inner and the intermediate shafts• -Must flush between the Intermediate and the outer shafts • -Must flush the introducer device or what may replace its

function

Subclavian/Direct Aortic Handle Needs

• Handle• -Must be capable of at least 90% of surgeons being able to use

it with one hand• -Must be ergonomic and create no strain in the surgeon’s hand• -Must not be off balanced to a degree where it troublesome to

use• -Must not be too short• -Must have a capsule quick closure system incorporated for

post deployment of valve

Subclavian/Direct Aortic Handle Needs

• Safety• -Must not be able to deploy capsules in

the wrong order• -Must not be able to quick close capsule

before the valve is deployed• -Must have a safety stop before the

opening point of no return on the valve• -Must keep flushing fluid inside handle

during procedure

Subclavian/Direct Aortic Handle Needs

• Capsule• -Must be A-traumatic• -Must be able deploy in a small area• -Must avoid all valve snagging• -Must be visible under fluro• -Must contain a 23mm valve and/or a 26mm valve• -Must have a working capsule attachment method• -Must have correct travel distance• -Must have an appropriate travel ratio

Subclavian/Direct Aortic Handle Needs

• Shaft length• -Must keep the surgeon out of the fluro• -Must be short enough to avoid a high percentage error• -Shaft stack up must match accordingly, allowing the

shafts to be flushed but not too much space in betweenShafts-Must be flexible-Must not over flex-Must not kink-Manufacturing processes must be non toxic-Must be able to carry or pull under force-Must not elongate over 2%-Inner diameter and outer diameter to match with 5-10 thousand of an inch clearance

Design Plan• Design Brief • Problem Definition/Statement • Research Report and Design Specification

• Project Planning and Control Document • Final Design Report • Component Configuration Sketches and Models • Human Factors Drawings and Mock-up’s • Conceptual Renderings • Concept Refinement Renderings • Design Intent and Control Documentation • Rapid Prototypes of parts • Final Product Prototype and Aesthetic Model • Showcase Presentation

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End of Presentation

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