Kurt Amplatz MDUniversity of Minnesota Hospital and Clinics Minneapolis, MNpresents

Recorded at the 3rd Pediatric Interventional Cardiac Symposium, September 1999, in Chicago, Illinois.

Nickel toxicity: what is the issue?

Société Française de Cardiologie Conclusions: CardioSEAL

1. no nickel

2. less bulky

3. better endothelialization

CardioSEAL metal

The metal of our competitor is MP35N with a 33% nickel content!

Amplatzer® devices from Felix Berger MD

Fig. 1 Implanted high-profile Amplatzer devices

Nickel allergy

Nine percent of the population is allergic to nickel. However implantation of nickel-containing prostheses and devices virtually never causes problems.

Allergy and nickel-containing implants

Dear Dr. Amplatz,

Many thanks for answering about percutaneous closure of ASD with the Amplatzer device in patients with allergy to nickel. As you know, I decided to perform the procedure in this young lady that presented with a cutaneous allergic reaction to nickel: The procedure was uneventful and at one month follow-up, no shunt was detected by Echo and she is doing fine…

Eustaquio Onorato MDClinica San Rocco Di Franciacorta SpAOme, Italy

An essential element

Nickel is an essential element for nutrition. Lack of nickel results in retarded body growth, anemia, and increased neonatal mortality in experimental animals.

Inorganic elements essential for life: Cu, Zn, Se, Mg, Mn, Ca, Fe, Mo, Ni, etc

Toxicity

Paracelsus (1493–1541): The factor determining whether a compound is toxic or not depends on the dose

Intake of nickel

Daily intake of nickel in the United States ranges from 300 to 600 micrograms per day.

Most of the ingested nickel is excreted via feces, urine, bile, and sweat.

Exposure to nickel

Nickel-containing alloys used in:

coins (quarters, nickels, euros)

knives, forks, spoons, etc

implants: wires, clips, coils, stents, nails, cava filters, prostheses, heart valves, pacemakers, etc

Anodic corrosion test

Fig. 2 Nitinol wire corroded by anodic dissolution for 2 minutes at 6 mA. Pits and corrosion products are obvious.

Explanted orthodontal arch wires

Fig. 3 Nitinol arch wire explanted at 1 month shows no evidence of corrosion.

Control Explanted wire

Implanted Amplatzer devicesAmin Z, et al. Circulation 1999;100:320-328

Fig. 4 Amplatzer devices implanted in a dog with 2 ventricular septal defects. The second device is a "dog-bone" design that was investigated in some animals.

Follow-up at 1 week

Fig. 5 One week after implantation, there is complete closure of the communication.

Follow-up at 1, 14, and 18 months

Fig. 6 At one-month follow-up, there is no change. Inspection at 14 and 18 months (not shown) confirms the same and demonstrates no aortic or tricuspid insufficiency.

Cardioscopy of right disks

First device Second device

Fig. 7 Right side of the device is completely endothelialized.

Cardioscopy of the left disks and valves

Fig. 8 Left side of the device shows complete endothelialization, except of the post. Cardioscopy, in other views (not shown), confirms normal aortic, mitral, and tricuspid valves.

Explanted Amplatzer devices

Fig. 9 Amplatzer devices, explanted at 18 months and polyester fabric removed, are indistinguishable from brand-new devices. There is not a single wire broken.

First device Second device

Human experience

September 1995: first implant in a patient

November 1998: device is intact and shows only total heart motion

Masura J, et al. Cathet Cardiovasc Diagn 1997;42:388-393

Nickel toxicity

Nickel toxicity occurs exclusively in nickel refineries due to inhalation of nickel carbonyl, Ni(CO)4, being part of the Mond process.

Explanted devices under light microscopy

Fig. 10 The explanted Amplatzer devices under light microscopy reveal a perfectly shiny surface with no evidence of pitting.

Explanted devices under scanning electromicroscopy

End disk Disk with female screw

Fig. 11 Scanning electromicroscopy again reveals no corrosion of the explanted devices.

Explanted devices at x3000 magnification

Fig. 12 At x3000 magnification, the explanted Amplatzer devices still show no corrosion. At this magnification, 1 mm would measure 3 m!

Control Explanted wire

Nickel corrosion in a biologic environment

A corrosion of 10% would produce a huge crater at 3000 times magnification and the daily dose of nickel would have been 15.4 micrograms, 33 times less than the daily intake.

Conclusion

“In conclusion, the results reported here suggest that there is no reason to believe that Nitinol wires are any more subject to corrosion than stainless steel wires in an environment that is typical of clinical service.”

Edie JW, et al. Angle Orthod 1981;51,4:319-24

Edie JW, et al (1981)