Endovascular Removal Tool. Senior Design Fall 2010 Christopher Guay Josh O Brien Catherine Yee Sponsor: Dr. Wei Sun, PhD

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1 Endovascular Removal Tool Senior Design Fall 2010 Christopher Guay Josh O Brien Catherine Yee Sponsor: Dr. Wei Sun, PhD

2 Outline Purpose and Background Previous Works and Methods Overview of the Device Dimensions Mechanisms of Motion Conclusion

3 Purpose and Background Remove calcified aortic valve leaflets before implantation of valve prosthesis. Current procedures only push diseased tissue to the side with stent. Increases safety- decreases chance of embolism, paravalvular leakage, or regurgitation. Increases longevity of patient and device. Decreases morbidity. For aortic stenosis- the most common valvular heart disease in the western world

4 Purpose and Background No open heart surgery. Minimally invasive: endovascular with a catheter threaded from femoral artery to aortic valve. Eliminates the risks and complications due to open heart surgery. Improved recovery time for patients.

5 Previous Works and Methods Teams since 2005 have looked to improve the efficiency of removing damaged aortic valve leaflets. None combined efficient cutting with debris removal. Products 2005: High pressured water streams to resect valves. Caused damage to aortic wall and was slow. (Georg Lutter et. al. Germany.) 2007: Er:YAG laser with fiber coupling device and tip. Still too slow for in vitro use and created debris that was too large. (Georg Lutter et. al. Germany.) March 2009: collapsible cutting blade made of Nitinol memory metal with saw tooth rotating punching technique. No debris removal component or in vitro testing. (Florian Hauke et al. Germany.)

6 Overview of the Device Threaded through arteries to aorta through a standard 24F catheter. Holder and Cutter expand to full diameter by external control. The holder acts as a stability point for device and keeps the necessary remains of the valve leaflets in place. It also serves as a cutting surface for blade. Cutting blade rotates at a designated speed to cut away at the calcified tissue. (A vacuum suction device collects the calcified debris for patient safety- not in prototype) After cutting, the holder and cutter collapse back into the catheter and is threaded back out of the arteries.

7 Component Overview Cutting Blade Assembly Holder Cutter Catheter Proximal Capsule Distal End Cap External shaft Internal shaft External Controls Motor User interface

8 Cutting Blade Blade made of 4 pieces of Nitinol. Connected with rivets, Serrated on 1 face. Opens to 16mm diameter. Rotational and linear motion.

9 Backplate Made of 4 pieces of Nitinol. Connected with rivets. Opens to 17mm diameter. Linear motion. Source of leverage.

10 Other Parts Proximal Capsule Thin stainless steel for enclosing of cutting blade. Distal End Cap Encloses holder and is linear actuator for holder. Catheter 24F Catheter than encompasses everything

11 Other Parts External shaft Within the catheter. For rotational and translational motion of cutter. Translational motion for expanding and collapsing the cutter. Made of Nitinol. Internal shaft Within external shaft. For translational motion of holder for expansion and collapse. Made of Nitinol.

12 Other Parts Motor DC brushless motor For cleanliness and coolness in operation. DC motor control and pulse width modulation output of a microcontroller. Closed loop feedback with sensor. On/Off power switch. User interface Keypad for user input to microcontroller and motor. LCD screen will relay speed of motor using microcontroller. Manual linear sliders on control box with indicators. On/Off power switch.

13 Final Assembly - Open

14 Dimensions All measurements refer to diameter. Device must fit within a 24F catheter - 7.6mm. Holder expands to 17mm. Blade expands to 16mm. Flexible Rotary shaft- 3.6mm OD, 3.3mm ID. Inner Actuator shaft- 2.7mm OD, 2.4mm ID. Rivets for cutter-.6mm. Linear actuators slide each slide 20mm.

15 Mechanism of Motion A double shaft made from Nitinol tubing is used. The hollow, flexible external shaft runs the length of the catheter in order to actuate the spinning blade at the proximal portion of the device. This shaft needs to be hollow to accommodate the internal shaft. It also would be actuated distally and proximally to move the cutting blade into position as well as to retract the blade back into the capsule at the end of its deployment. The internal shaft is the linear actuator that will translate motion to the end cap of the assembly, opening and closing the holder. An inner shaft which would fit very snugly within the external shaft.

16 Budget Al sheet metal $25 Speed Controller $50 LCD screen $100 Microcontroller $25 Power adapter (AC/DC) $100 Various wiring, electric components $50 Brushless Instrument Grade Motor $250 24F Catheter $100 Flexishaft (stainless steel, 2m) $90 Nitinol sheet stock(cutter) $400 Plastic capsule $20 Pig aorta (testing) $15 Additional equipment/ Unexpected Costs $1500 FINAL BUDGET $3000

17 Conclusion Endovascular heart tissue removal device Prototype will be tested on porcine aorta. Inserted percutaneously (no open heart surgery) Novel and unique Past procedures could not remove the original leaflet tissue Potential Patent Market to Hospitals

18 Acknowledgements Dr. Wei Sun James Paolino Memry Metal, Inc.