History

Hufnagel Aortic Valve

Year: 1954
Inventor: Dr. Charles Hufnagel
  • Implemented on a 30 years old woman, who leads a good normal life after surgery.
  • Fixation of ball-type valve into a descending aorta.
  • Rapid insertion of an acrylic ball into the descending aorta.
Material(s) used:
  • Plastic – the creation was a tiny plastic tube with a plastic ball in the center .
  • Silicone- the noise was coming from the silicone layer.
Advantages:
  • Proven that synthetic material can be used for heart valve creation.
Disadvantages:
  • Can only be placed on descending aorta, not inside the heart itself.
  • Did not fully correct the valve problem; rather alleviate the symptoms.
  • Valve prevented regurgitate flow only from the lower body.
  • Embolization and thrombosis occurred frequently.
  • Noise generated by valve was discomforting to the patient.

Starr-Edwards Ball Valve

Year: 1960s
Inventor: Starr-Edward, Dwight Herken
  • Modification of Hufnagel’s.
  • Ball of valve was slightly smaller and caged from both sides.
  • Aim was to improve in terms of durability and rigidity of components.
  • It was the first successful orthopedic valve replacement in the mitral position. Then continued by Harken at the aortic position by means of implantation of prosthesis.
  • Material’s criteria needed to be chemically inert, compatible with human tissue, atraumatic to blood and nonthrombogenic.
Advantages:
  • Can be inserted to heart itself.
  • Embolization rate reduced.
Disadvantages:
  • Patients continued to required permanent anticoagulant therapy.
  • Fraying of the fabric, excessive ingrowths of tissue, and obstructed blood flow.

Tilting Disk - Bjork-Shiley Valve

Inventor: Bjork Shiley
  • To minimize resistance to forward flow, decrease turbulence, limit regions of stagnation, reduced shear stress.
Advantages:
  • Blood flow naturally.
  • Reducing damage to blood cells from mechanical forces.
  • Anticoagulant requirement reduced.
Disadvantages:
  • Struts from the valve tend to fracture over time due to fatigue.
  • Thrombolism could not be eliminated.

Bi-leaflet Valve

Year: 1977
  • Consists of two leaflets that are crescent and revolve about struts that are stacked to the covering of the valve.
  • Aimed to approach ideal central unimpeded flow, and to improve hemodynamic and application of thromboresistant alloys and advanced ceramics. 
Material(s) used:
  • Alloys
  • Ceramics
Advantages:
  • Blood flow directly through the centre of these valves.
Disadvantages:
  • Allows some backflow.

continue to MATERIALS>>
TOP PAGE
Subscribe to: Posts (Atom)