Prosthetic Valves

Question 1

What is most well known caged ball mechanical valve?

Answer 1

Starr-Edwards high profile ( tall cage), it has a turbulent high velocity peripheral circumferential jet. No flow thru the center of the prosthesis due to location of the ball

Question 2

Mechanical Caged disc?

Answer 2

low profile (short cage), flow had to change direction around the occluder, increased pressure gradient, cell damage,

Question 3

Mechanical tilting disc?

Answer 3

Bjork-Shiley, pivoting disc (toilet seat), creates a major and a minor orifice

Question 4

Mechanical Bi-Leaflet

Answer 4

St. Jude, 2 tilting discs, creates 3 orifices and least stenotic of all the mechanical prosthetic valves.

Question 5

Bioprosthetic Valves

Answer 5

All made to resemble AOV, used in AOV or MV position. All have 3 cusps

Question 6

Heterograft (xenograft)

Answer 6

Animal to human valve, pig = porcine AOV = Carpentier-Edwards or the cow = Bovine pericardium to fashion the valve

Question 7

Homograft (allograft)

Answer 7

person to person, preserved human tissue from a cadaver, usually AOV. stented or stenless, used for AOV or PV replacements, rarely used for MV or TV replacements

Question 8

What is TAVI or TAVR

Answer 8

Transcatheter Aortic Valve Implant/Replacement, cath delivered biologic tissue valve mounted in stent

Question 9

What are 2 approaches for TAVI?

Answer 9

Transfemoral or trans-apical

Question 10

Echo in TAVI

Answer 10

evaluate AS preprocedure - AI = careful eval of LVOT and annulus msmts. Device migration or significant paravalvular leak from under-sizing device. And problems crossing AOV from oversizing device

Question 11

Valved conduits

Answer 11

Used for congenital repairs, homograft or goretex or dacron material, may have mechanical or bioprosthetic valve

Question 12

Carpentier Ring

Answer 12

Used for TV/MV repair, serves as annulus to support valve leaflets

Question 13

Selection of a Tissue valve for?

Answer 13

Elderly where long-term durability is less important, patients where chronic anticoagulation is not advised or those at an increased risk for thromboembolism

Question 14

Selection of a Mechanical Valve for?

Answer 14

Children and young adults except women in their child bearing years, patients with renal failure, small valve annulus, high reoperative risk, A-FIB, and patients requiring AOR replacement - such as AO dissection with severe AI

Question 15

What might be an advantage of a bioprosthetic over a mechanical valve?

Answer 15

Can be stentless, central flow dynamics and may avoid anticoagulation

Question 16

Normal prosthetic valves have higher flow velocities than native valves

Answer 16

True

Question 17

All prosthetic valves are inherently stenotic compared to a normal native valve

Answer 17

True

Question 18

P 1/2 time is going to overestimate or underestimate the MVA of a mechanical valve

Answer 18

Overestimate the MVA of a mechanical valve

Question 19

Is P 1/2 time ok for bioprosthetic valve area calcs?

Answer 19

Yes

Question 20

What to check for when doing an echo

Answer 20

Type of valve, dehiscence, gradients, areas and regurg lesions, normal versus peravalvular leaks, LV fx, leaflet motion, occluder/poppet motion, vegs, thrombus, pannus ingrowth of tissue, calcific changes and abscesses

Question 21

What are some pitfalls & tech difficulties of mech valves?

Answer 21

Reverberations, acoustic shadowing, flow masking, flow characteristics vary with type of valve = be aware of overestimation potential. Struts will cause pressure recovery interruption and throw off calcs. cause tapered shape.

Question 22

Mechanical Valve dysfunction?

Answer 22

With the valve itself, ball variance, thrombus formation, pannus ingrowth or endocarditis, tissue around the valve

Question 23

Tissue valve dysfunction?

Answer 23

Tissue degeneration, problem with prosthetic valve,
problem with tissue around the valve, can be caused by endocarditis or abscess, loose/torn sutures or calcific changes in the native annulus

Question 24

What is Ball Variance?

Answer 24

Changes in the disc or ball due to abrasion and deposits of blood lipids. Results in changes in size or contour of the ball or disc.

Question 25

Signs of Prosthetic Valve Dysfunction?

Answer 25

Reduced or compromised CO, Increase in forward flow velocity(decrease in valve area), Increased regurg by DFI, Increased signal intensity of CW doppler regurg, progressively increasing chamber size on serial studies, persistent LVH, recurrent PHTN following initial decline in pulmonary pressures.