PERCUTANEOUS AORTIC
`VALVE REPLACEMENT
`
`I, Anatomyifl
`The aortic valve is a structure whose function is to direct the flow of blood from
`
`It accomplishes
`the left ventricle into the systemic circulation through the aortic artery.
`this function by opening during the contraction of the left ventricle and closing when the
`left ventricle relaxes. The aortic valve is a tricuspid structure and each cusp folds up
`toward the aorta during the ,comrag‘gigtlwghase and then fold back against each other in the
`relaxation phasedfigure 1 bhow a__pictu©t However, the aortic valve is a complex
`structure with integral relatioflslfi’p's/beyon'd merely a three leaflet valve. For instance,
`each leaflet sits directly opposite an outpouching of the proximal aorta. This dilated
`segment is called the®inus of@1lsalva, and it is this anatomic relationship that assi
`he
`valve to open and close repetitively while minimizingthe stress upon any point wit
`in
`- vii-V his valvular apparatus. Further, the proximangrionthhe aortic valve is highly elasti@
`,.;
`5
`
`.,,:3N{33 tat-67‘ 4,,
`and withwthiselasticity‘itcarhdilate during theic‘oiitr' njfphase of the left ventricle.
`‘
`Historically, it has been theorized that this reducesthe amount of work that the left
`“/4th
`ventricle performs. As with anythinginnaturgit is- muchmore complex. The valvular
`structure’sqare integrally related to the coronary arteries. The function of the coronary
`"\‘éwfieriéfli to supply bloodW to the heart. These, as represented in figure 2, are
`,7 (locatedW1thirl'2mgofthe'SinuseE In a normally functioning valve, the cusps open widely to
`1 allow the unimpeded"'trafifi1'ence ofblood, and then close tightlyflnetallewingw-anyto i prr‘fivdpml’”
`:Tegurgitaterback into the left ventricle. When there is significant restriction to blood
`t”. ‘5“ ”I
`7 flow, this is called stenosis, and when it allows blood back into the left ventricle it is
`'regurgitation. Thus, each component plays a vital role in the function and durability of
`the valve.
`
`l
`
`The first components of the valve I would like to discuss are the leaflets.
`Interestingly, the number offing leaflets within a normal aortic valve does not vary to a
`significant degree. When there are less than three valves, the valve undergoes rapid
`stenosis and restriction. Among congenital alterations upon the valve number-,the most
`frequently encountered is a bicuspid aortic valve. This condition is the most common
`defect that is survived into adultDlood. However, this valve predictably becomes more
`and more stenotic and regurgitant by the 411] and 5th decade. Unfortunately, this usually
`results in the need for surgical replacement. A unicus
`valve rarely survives beyond
`the first year of life,,(figures 3 and 4), Rarely)a quadricusped valve will be shown to
`survive into adulthood. This design also results in marked stenosis.
`Further, the cusps
`are shaped in a defined convexity. This design ermits the.dispersion..of.,,pressure over a
`x
`mm
`WWW‘WM WWMWW
`larger surface areas“: I, hisfldispvewrvsrgnwrefisuistswthe e
`
`particlular place. fiMoreover, this curvature allows the leaflet to reverse curvatuK'An/
`a”abifity needewdwiiiflorder to fold and allow the maximum openingmdiwawrnewtermduring,,...-
`contraction? Finally, ”a"curvEdfiesi‘gnmallows a redundancy in the coaptation site of the
`leaflets. The area of coaptation is the edge of the valves that must meet and close in
`.ng pr,_g.t).sa.xtv order'formtheremneMe-be regurgitation. Hence, both the number of leaflets and their
`,2
`overall shape is important in the function and durability of the valve,
`:
`As mentioned earlier, the valve leaflets have a direct relationship to thfiinus’s of
`[Qalsalva The sinus diameter is almost twice that of the aorta.
`This cavity plays an
`important role in the mechanism of valve closure (referenced Mano Thubrikar). An
`
`NORRED EXHIBIT 2049 - Page 1
`Medtronic, Inc., Medtronic Vascular, Inc.,
`& Medtronic Corevalve, LLC
`
`v. Troy R. Norred, MD.
`Case |PR2014-00110
`
`