3. HISTORICAL NOTE - 1916 - 1935
Heparin was discovered by Jay Mclean and William
Henry in 1916, although it did not enter clinical trials until
1935
MCLEAN, J. (1 January 1959). "The Discovery of Heparin". Circulation. 19 (1): 75β78.
4. HISTORICAL NOTE - 1953
The first successful open heart operation using cardiopulmonary
bypass was done by John Gibbon on May 6, 1953. The operation was
closure of an atrial septal defect. The patient, Cecelia Bavolek, was
alive and well on the 50th anniversary of that operation in May 2003.
5. HISTORICAL NOTE - 1954
In 1954, Charles Hufnagel and his colleagues described 23 patients
with aortic insufficiency who had been treated by rapid insertion of an
acrylic ball valve into the descending aorta
6. The first mechanical replacement valve was created and
implanted by Albert Star and Lowell Edwards in America in
1960.
HISTORICAL NOTE - 1961
7. The first valve replacement from a human patient was first
performed in 1962 by Donald Ross
Surgeon Alfred Gunning, from Oxford, had been using freeze-dried
valves from donated corpses for his research. He gave some of these to
Donald Ross
HISTORICAL NOTE - 1962
8. Mechanical
- Other mechanical valve (I)
- >60 years (aortic)*
- <65 years (mitral)*
- Other strong indication
for anticoagulation
Bioprosthesis
- <60 years (aortic)*
- >65 years (mitral)*
- Younger patients who
wish to avoid (IIa) or
have contraindications to
anticoagulation (I)
- Future pregnancy (IIb)
INDICATIONS
9. The ideal prosthetic valve
The ideal valve substitute should mimic the characteristics
of a normal native valve.
In particular, it should have:
- excellent haemodynamics,
- long durability,
- low thrombogenecity,
- excellent implantability
- preserve surrounding tissue
- unidirectional flow
- cheap
13. A- Caged Ball Valves
which consist of a silastic ball with a circular sewing ring
and a cage formed by 3 metal arches, are no longer
implanted.
14. composed of a single disk secured by lateral or central
metal struts. The opening angle of the disk relative to
valve annulus ranges from 60Β° to 80Β°, resulting in 2
distinct orifices of different sizes.
B- Tilting disc Valves
15. made of 2 semilunar disks attached to a rigid valve ring
by small hinges. The opening angle of the leaflets
relative to the annulus plane ranges from 75Β° to 90Β°,
and the open valve consists of 3 orifices
B- Bileaflet Valves
17. Porcine bioprosthetic valves:
consist of 3 porcine aortic valve leaflets crosslinked
with glutaraldehyde and mounted on a metallic or
polymer supporting stent.
Bovine Pericardial valves:
fabricated from sheets of bovine pericardium mounted
inside or outside a supporting stent.
A- Stented Heterograft Valves
20. B- Stentless Heterograft Valves
developed in an effort to improve valve hemodynamics
and durability.
Porcine valves Bovine valves
21. Aortic valve homografts are harvested from human cadavers
within 24 hours of death.
They are treated with antibiotics and cryopreserved at β196Β°.
C- Homograft Valves
23. E- Percutaneous Bioprosthesis
balloon - expandable Self - expandable
The valves are usually implanted using a percutaneous
trans-femoral approach or trans-apical via thoracotomy.