Biomedical Engineering Reference
In-Depth Information
Table 5.2 Parameters for heart valves
Surgical and patient parameters
Parameters relating to device function
Factors relating to device design
Treatment and
surgical
parameters
Patient health and
medication
Design
parameters
Failure modes
Device
configuration
Material properties
Approach to
heart
· Surgical
· Minimally
invasive
· Catheter
delivery by cut-
down or
percutaneous
Valve size and
difficulty in
placement
Placement and
suturing
techniques or
percutaneous
stent placement
Preservation of
chordae tendons
and papillary
muscle
Medication pre-op,
peri-op, and post-op
Anticoagulant/anti-
platelet/ thrombolytic
regimen
Prophylactic antibiotics
Adverse coagulation
states, e.g., hyperco-
agulable
Diabetes: inhibition of
fibrosis/healing of
grafts
Diseases, e.g.
congestive heart failure
Previous valve or
annuloplasty ring
Surgical vs
percutaneous
delivery
Method of
attachement to
heart
60 to 160 beats/
min
>20 year lifetime
Large effective
orifice area
Minimum
regurgitation
Fluid flow
modeling:
Hemodynamics
of valve to
approximate
natural valve
Thrombus/emboli
Tissue overgrowth from
sewing ring or pannus,
hyperplasia at stent/
valve interface
Infection
Hemolysis
Destruction of blood
elements
Degradation/
calcification of
bioprosthetic tissue
valves
Fatigue of valve
components
Fracture
Stress corrosion
Catheter design for
percutaneous valve
Ability to mount for
percutaneous
delivery
Ball in cage
Disk in cage
Tilting disk
Bileaflets
Flexible polymer
leaflet
Porcine heart valve
Bovine pericardial
valve
Homograft valve
Strength
Compliance
Creep resistance
Fatigue resistance
Fracture toughness
Lubricity
Porosity (tissue
ingrowth into cuff)
Lack of chronic
inflammatory
response in chronic
applications
Lack of thrombus
and emboli
Biostability
Sterilizability
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