STI has acquired a wealth of experience in the manufacturing of metal frames for trans-catheter aortic valves by supporting the development of various types of artificial heart valves and providing contract manufacturing services to a tier-1 company operating in this specific niche.

Raw materials

The metal frame of a heart valve can be made from Stainless Steel (SS316LVM), Cobalt Chrome or Nitinol. The metal frame has a crimped diameter of 6-8mm and an expanded diameter varying between 21mm to 29mm, depending on the patient.

Laser machining

Existing frame fabrication methods include wire braiding or knitting and laser tube cutting. Today, most heart valve frames are being fabricated by laser cutting metal tubes of various diameters, lengths and wall thickness.

Heat treatments

Balloon-expandable frames made of stainless steel and cobalt chrome alloys undergo annealing to relieve internal stresses, soften the metal, improve elongation rate, lower the risk of strut breakage, and improve fatigue resistance. Self-expanding frames utilize the elastic properties of Nitinol and require a different process called shape-setting to set the expanded diameter of the frame and fix the transition temperature and affects the radial force.

Surface treatments

Post laser processing steps may include: mechanical deburring, pickling, electropolishing, passivation and cleaning. These steps result in a high-quality biocompatible product having a bright, shiny surface, free of defects, and improved corrosion resistance.

Quality assurance

Visual and dimensional inspections carried out throughout the manufacturing process ensure that the final product meets the customer’s specifications. Quality assurance inspections use high-resolution optical microscopes, automatic digital micrometers, and video inspection systems. STI’s frame manufacturing procedures adhere to EN ISO 13485 and ISO 9001 quality standards.