PERCUTANEOUS AORTIC
`
`VALVE
`
`REPLACEMENT
`
`The aortic valve undergoes a series of changes based upon the initial
`structure at birth and the dynamic stresses, which it has to undergo daily.
`The trileaflet aortic valve will not become stenotic usually until the 7th
`decade unless infectious processes are introduced sooner. The incidence of
`aortic stenosis can reach between 2 to 9 % in this age range. The average
`mortality rate at all ages is 9% /year which also increases as a population
`ages. Coupled with these facts is the likelihood that as a person ages and
`becomes symptomatic with aortic stenosis, he is less likely to be an
`operative candidate. The mortality of octogenarians has been reported as
`high as 20% for aortic valve replacement that can preclude a reasonable
`attempt at the therapy of choice, which is surgical replacement.
`
`In an attempt to formulate an effective therapy for this class of patients, I
`have designed a series of devices, which can be placed nonsurgically so as to
`. minimize the risk to the patient during the procedure. This procedure
`involves novel as well as known equipment and, techniques.
`
`The first in a line of options involves the placement of an aortic valve
`incorporated within a stent. This device would be anchored in the ascending
`aorta with further support supplied in branch vessels or descending aorta as
`seen necessary by the stress forces placed upon the artificial valve and
`calculated before the procedure (please see appendixl). The valve would be
`connected to the stents by serially connected rods. This design would
`displace the forces placed upon the artificial/biomechanical/bioprosthetic
`valve across a large surface area. Placing the device nonsurgically
`eliminates the need for bypass pump or sternotomy for placement.
`FIGURE 1. There are several variations to the valve design that can be
`utilized using these techniques and concepts. The first is the umbrella
`shaped valve, which would be placed in a position above the native valve,
`and when it collapses, would seal the opening between the aorta and left
`ventricle. This would also make it ideal for those patients who primarily
`have aortic regurgitation. The hinges can be of several types: (in order to
`produce as much laminar flow characteristics as possible) 1. Stainless steel
`rods enveloped within a rubber or plastic polymer that would withstand
`
`NORRED EXHIBIT 2052 - Page 1
`Medtronic, Inc., Medtronic Vascular, Inc.,
`& Medtronic Corevalve, LLC
`
`v. Troy R. Norred, MD.
`Case |PR2014-00110
`
`

`

`sheer stresses with opening and closing; 2. Rubber and plastic polymer with
`the thickest portion at the bases and the narrowest portions at the center so
`that it folds during systolic contraction of the left ventricle. The tip of the
`valve would be of a semicircular design to permit the much desired laminar
`flow characteristics of the aortic valve. This would decrease the shear stress
`
`placed upon the aortic root and ascending aorta. The design may also
`incorporate a semi circular configuration opposing the sinuses of valsalva so
`as to disperse the stress upon the aortic valve along a larger surface area and
`to maximize the flow characteristics to the coronary arteries. This valve
`would be placed within a catheter system. However a steering and
`placement mechanism, incorporating a connection of removable rods guided
`by a half ball configuration, may be necessary. The femoral artery would be
`accessed and cannulated. The femoral vein would be accessed and
`
`cannulated. Both an antegrade and retrograde approach would be used to
`place the stent/valve combination within the right anatomical position. The
`visualization would utilize continuous roentgenogram and ultrasound
`techniques, which are currently available. The most important visualization
`tool would be ICE (intracardiac echocardiography). In this valve model,
`direct connection of the valve to the aortic root would not be utilized unless
`
`the direction of the jet from the aortic valve made it necessary. The
`procedure would involve inflation of balloons within the aortic valve and
`ascending aorta to deploy the stent/valve combination. If traditional
`valvuloplasty does not produce significant enough opening of the aortic
`valve and relieve the gradient between the left ventricle and aorta then a
`series of further steps may be required.
`Removal of the native aortic valve would not be necessary. The focus
`would instead be upon debulking of the native aortic valve. The central
`theme would hinge upon abolition of the resting gradient. The techniques
`employed would attempt to achieve a large effective aortic valve area
`regardless of the functioning of the native valve post—procedure because an
`artificial valve designed to prevent aortic regurgitation would be in place.
`The valves are designed not to hinder the ejection of blood from the left
`ventricle, and to minimize the aortic regurgitant volume. These techniques
`may include the positioning of an Er—YSGG percutaneous laser to decalcify
`the valve and repeat balloon aortic valvuloplasty. If not effective then high
`frequency ultrasound percutaneously applied may be necessary. These
`techniques have been shown to be highly effective at producing debulking
`and preventing restenosis. However, they produce tremendous aortic
`regurgitation. This would not be a problem for the unattached valve which
`would work as stated previously for aortic regurgitation. 1f the desired
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`NORRED EXHIBIT 2052 - Page 2
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`results were not seen then a host of options are still available; for example,
`two rings could be guided onto both the aortic and ventricular sides of the
`native aortic valve and pneumatically sealed together. Then expandable and
`retractable biotomes could be percutaneously placed for controlled
`dissection of the native aortic valve. Along this concept, the biotomes could
`be used for primary resection without stabilizing rings, but there would need
`to be a stabilization mechanism. Another such mechanism could employ the
`use of a micro screw into the native valve, which would act as an anchor to
`guide a biotome onto the native valve. Then the biotomes would take small
`snips in a controlled fashion off of the native valve. This would gradually
`increase the effective orifice area. Excitingly, because the artificial valve is
`not anchored or dependent upon the native valve for its function, this
`technique could be easily reapplied, if the native valve were to restenose,
`without compromising the artificial valve. A tremendous advantage of this
`procedure would be its independence from a need for a percutaneous bypass
`
`pump.
`
`The second valve design could be best described as a conical design. It
`would be composed of 16 to 32 individual rubber/plastic/metal plates, which
`would be interconnected by resistant fabric. Figure 2 shows how this valve
`would be connected together. It would be placed in direct opposition of the
`native aortic valve. It would expand during systole and collapse during
`diastole.
`It would also be anchored along the aortic root wall with
`connecting rods to the ascending aortic stents. The rods would be placed
`between the right and left coronary ostia tangentially along the sinus of
`valsalva. In this design there would not be any intraluminal rods within the
`ascending aorta as with the umbrella design. The techniques described
`above to relieve the aortic stenosis would also be applicable to this valve.
`This valve however may not be the best valve for isolated aortic
`regurgitation given the direct placement of the valve over the native valve
`may impede opening and create an outflow obstruction. However, given the
`curved and redundant nature of this valve, and the fact that it centralizes the
`ejection jet from the left ventricle, it may produce the most laminar flow
`characteristics and the least hematologic sequelae. The edges may need. to
`have a loose rim of pliable material, which act as a flap valve, to help reduce
`peri—valvular leaks (See appendix). To minimize components and to aid in
`miniaturizing the device for delivery, the connecting cones can be reduced to
`2 - 4 interconnecting rods, which are draped in a sheet of fibrous polymer
`(See appendix).
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`NORRED EXHIBIT 2052 - Page 3
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`Other valvular designs which may prove valuable to this technique include
`the usage of cadaver/porcine incorporated valves placed within a
`percutaneously stented system and would have the benefits of favorable flow
`and hematologic characteristics. The initial designs are shown in the
`appendix. Also tilted disk/duo disk design could be hinged and compacted
`Within a percutaneous system to provide reasonable partition between the
`left ventricle and aorta, However, these valves have been shown. to have less
`favorable hematologic sequelae. The central themes involve increasing the ,
`effective aortic valve orifice area while minimizing the resultant aortic
`regurgitation. Thusa the goals in reducing lefi ventricular energy expenditure
`and its resultant long-term sequelae of pressure overload would be met with
`this system of percutaneously delivered aortic valve/s.
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`NORRED EXHIBIT 2052 - Page 4
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