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Understanding the mechanical and structural properties of bioresorbable scaffolds (BRS) is crucial for appropriate implantation.
We compared the mechanical and physical properties of the magnesium BRS, Magmaris (Biotronik, Bülach, Switzerland) with the Absorb BRS (Abbott Vascular, Santa Clara, CA, USA) and the DESolve CX BRS (Elixir Medical Corp., Sunnyvale, CA, USA) and the permanent metallic drug-eluting stents (DES) Xience Xpedition (Abbott Vascular, USA) and the Promus Premier (Boston Scientific, Natick, USA). We measured crossing profile of 3.0 mm devices, recoil, radial strength and limit for post-dilatation before fracture, safety of side branch dilatation and mini-kissing balloon dilatation.
The crossing profile (mm) for Magmaris BRS was numerically greater than for Absorb BRS (table 1) and these were greater than for the metallic DES Promus Element and Xience Xpedition. For a 3.0 mm Magmaris scaffold, no fractures were observed after main branch post-dilatation with 4.0 mm NC balloons for pressures up to 24 atm. For dilatation through stent cells, no fractures were observed with a 3.0 mm NC balloon up to nominal pressure. A single fracture in a connecter was observed after mini-kissing technique with two 3.0 NC balloons at 5 atm. All other fractures caused by mini-kissing balloons occurred at pressures above 17 atm. Crossing profile, radial strength, post-dilatation and side branch dilatation results are presented in table 1.
|Magmaris||Absorb||DESolve CX||Promus Element||Xience Xpedition|
|Crossing profile (mm)||1.48±0.01||1.43±0.02||1.41±0.02||1.10±0.01||1.14±0.01|
|Radial strength. Pressure (Bar) to reduce cross-sectional area by 10%||1.26±0.23||1.27±0.14||1.84±0.16||1.45±0.13|
|Radial strength. Pressure (Bar) to reduce cross-sectional area by 25%||1.8±0.08||1.37±0.18||1.97±0.12||1.6±0.10|
|Fractures after post-dilatation with 4 mm balloon||None||At 10 atm||None||None|
|Fractures after side-branch dilatation with 3.0 mm balloon||None||At 14 atm||None||None|
The Magmaris scaffold has a numerically larger crossing profile compared with Absorb BRS. It was more resistant to strut fracture with main branch post-dilatation, side-branch dilatation and mini-kissing post-dilatation, and had greater radial strength than Absorb.
CORONARY: Stents: Bioresorbable Vascular Scaffolds