title: Negative vascular remodelling after implantation of bioabsorbable magnesium alloy stents in porcine coronary arteries: a randomised comparison with bare-metal and sirolimus-eluting stents.
abstract: OBJECTIVE
  We sought to assess vascular remodelling and neointima formation after implantation of bioabsorbable magnesium alloy stents (AMS).
  
  
  METHODS
  Randomised experimental study.
  
  
  METHODS
  AMS (n = 11), sirolimus-eluting stents (Cypher; n = 11) and bare-metal stents (BMS; n = 9) were randomly implanted in 31 porcine coronary arteries (n = 11 pigs).
  
  
  METHODS
  Neointima formation was measured by histomorphometry at 90 days. Vascular remodelling defined as change in external elastic membrane area from index intervention to follow-up was assessed by serial intravascular ultrasound (IVUS).
  
  
  RESULTS
  By histomorphometry, lumen (median (quartiles); AMS: 1.75 mm2 (1.07-3.26), Cypher 2.52 mm2 (2.22-5.01), BMS 4.55 mm2 (3.2-7.44); p = 0.013) and external elastic membrane area (AMS: 5.56 mm2 (4.09-6.95), Cypher 7.95 mm2 (6.45-10.92), BMS 9.08 mm2 (7.85-11.63); p = 0.014) were smallest after AMS implantation. By IVUS, external elastic membrane area at follow-up was smallest (AMS: 7.5 (2.8) mm2, Cypher 9.1 (2.7) mm2, BMS 9.9 (3.1) mm2; p = 0.33) and change in external elastic membrane area from index intervention to follow-up (remodelling; AMS: -1.0 (3.1) mm2, Cypher 1.0 (0.8) mm2, BMS 0.9 (1.2) mm2; p = 0.30) was greatest in the AMS group. In a dichotomised IVUS assessment of vascular remodelling, six AMS stents were remodelled (negative remodelling: n = 5; positive remodelling: n = 1) at 90-day follow-up (AMS versus Cypher + BMS: p = 0.001). Neointima formation was smallest in the AMS group (p<0.05 for both histomorphometry and IVUS).
  
  
  CONCLUSIONS
  Coronary implantation of absorbable magnesium stents, compared to two non-absorbable stents, was associated with the smallest lumen area at three-month follow-up because of negative vascular remodelling.
authors: Department of Cardiology B, Aarhus University Hospital, Skejby, Brendstrupgaardsvej, DK-8200 Aarhus N, Denmark. michael.maeng@ki.au.dk
authors: M
authors: M
authors: Maeng
authors: L O
authors: LO
authors: Jensen
authors: E
authors: E
authors: Falk
authors: H R
authors: HR
authors: Andersen
authors: L
authors: L
authors: Thuesen
mesh_terms: D020341:Absorbable Implants / Q000009:adverse effects*; D000497:Alloys / Q000009:adverse effects; D000818:Animals; D003331:Coronary Vessels / Q000000981:diagnostic imaging / Q000473:pathology*; D054855:Drug-Eluting Stents / Q000009:adverse effects; D007166:Immunosuppressive Agents / Q000008:administration & dosage*; D008274:Magnesium / Q000009:adverse effects; D011897:Random Allocation; D020123:Sirolimus / Q000008:administration & dosage*; D015607:Stents / Q000009:adverse effects*; D013552:Swine; D013997:Time Factors; D017539:Tunica Intima / Q000473:pathology; D018084:Ultrasonography, Interventional
chemical_list: D000497:Alloys; D007166:Immunosuppressive Agents; D008274:Magnesium; D020123:Sirolimus