Biocorrosion of magnesium alloys: a new principle in cardiovascular implant technology?
- 1Hannover Medical School, Leibniz Laboratory for Biotechnology and Artificial Organs, Hannover, Germany
- 2Institute of Materials Sciences, University of Hannover, Hannover, Germany
- 3Department of Cardiology, University of Magdeburg, Magdeburg, Germany
- Correspondence to:
Dr B Heublein, Leibniz-Laboratorien, Oststadtkrankenhaus, D-30659 Hannover, Germany;
- Accepted 19 February 2003
Objectives: To develop and test a new concept of the degradation kinetics of newly developed coronary stents consisting of magnesium alloys.
Methods: Design of a coronary stent prototype consisting of the non-commercial magnesium based alloy AE21 (containing 2% aluminium and 1% rare earths) with an expected 50% loss of mass within six months. Eleven domestic pigs underwent coronary implantation of 20 stents (overstretch injury).
Results: No stent caused major problems during implantation or showed signs of initial breakage in the histological evaluation. There were no thromboembolic events. Quantitative angiography at follow up showed a significant (p < 0.01) 40% loss of perfused lumen diameter between days 10 and 35, corresponding to neointima formation seen on histological analysis, and a 25% re-enlargement (p < 0.05) between days 35 and 56 caused by vascular remodelling (based on intravascular ultrasound) resulting from the loss of mechanical integrity of the stent. Inflammation (p < 0.001) and neointimal plaque area (p < 0.05) depended significantly on injury score. Planimetric degradation correlated with time (r = 0.67, p < 0.01).
Conclusion: Vascular implants consisting of magnesium alloy degradable by biocorrosion seem to be a realistic alternative to permanent implants.