Module 2- Heart Valves Flashcards
Graphics about the prevalence of valvular heart disease
Valvular Heart Disease, an under-appreciated yet serious and growing public health problem.
Diagram of healthy and diseased aortic valves
Normal valve mechanism
The normal valve mechanism is to ensure unidirectional blood flow.
What are the consequences of valvular heart disease?
Consequences include: hypertrophy, local turbulence, decreased circulation, and diminished life expectancy
Valvular stenosis vs. regurgitation
Devices for Valve Replacement: Mechanical Valves
- Mechanical valves are fabricated from metals, alloys, and plastics (silicon-carbide)
- They are generally durable and reliable
- Patients must be on anticoagulants for life
Timeline for mechanical valves
Mechanical valves disrupt normal flow
What can go wrong with a mechanical valve?
On-X Prosthetic Heart Valve
Increased biocompatibility due to the use of pure carbon rather than silicon-carbide.
On-X Prosthetic Heart Valve- comparison with traditional valve
Overview of tissue valves
- Mechanical valves are fabricated from animal tissue
- They are chemically modified with glutaraldehyde (no immunosuppression)
- Need to be replaced every 10-15 years
Tissue (bioprosthetic) Valves: Xenografts
Lifespan of tissue valves and complications
Worn-down tissue valves start to form blood clots, the tissue deteriorates, and calcification occurs
Graphs showing survival and probability of death with mechanical vs. biological valve
Valve Replacement Surgery
The heart is accessed through a chest incision (A). The patient’s heart function is replaced by the heart-lung machine. The aorta is cut open to reveal a diseased aortic valve (B), which is then removed. A valve sizer is placed in the opening to determine the size of prosthesis needed (C). A prosthetic valve is sutured in place (D and E).
The Ross Procedure
- The root is the valve along with the surrounding vessel
- In the Ross Procedure, the pulmonary valve replaces the aortic valve (allograft)
- The pulmonary valve is then replaced (it is less likely to wear out than the aortic valve)
Transcatheter Valve Replacement (“Valve-in-Valve” replacement)
Transcatheter Valve Replacement video
https://www.youtube.com/watch?v=X1Uk9Jvbut0
Transcatheter Mitral Valve Repair: The Mitraclip
In 2013, this device became the first FDA-approved alternative for mitral regurgitation
Mitraclip video
https://www.youtube.com/watch?v=R4SBHFcDemA
Ventricular Assist Device (VAD)
- The VAD is an artificial pump that aids or replaces the ventricle function
- Two types of pumps: pulsatile pump and continuous pump
- Increases blood flow to the body
A bridge to transplant: The Total Artificial Heart
- The goal of the total artificial heart is to provide complete cardiac replacement, removing the diseased heart
- However, major challenges remain, including hemocompatibility, invasiveness, and reliability
Key events in development of the total artificial heart
1920s Brukhonenko Mechanical pumps in Animals
1930s Lindberg &Carrel Blood pumps for organ perfusion
1964 NIH Artificial Heart Program Established
1969 Cooley Extracorporeal TAH as bridge to transplant
1998 Baxter-Novacor First FDA product approval as bridge to transplant
Diagram of person with total artificial heart
Artificial heart- survival rate, cost, etc.
- Abiomed total artificial heart
- Clinical trials
- Survival up to 18 months (although average is much less)
- Costs $1 million per procedure
More pictures of artificial heart
Clinical trial approved for Syncardia heart in 2015
Artificial heart video
http://www.youtube.com/watch?v=LySZtgYK4gw
Total artificial heart- FDA
Future possibilities- silicone artificial heart
