Effect of non‐compliant balloon postdilatation on magnesium‐based bioresorbable vascular scaffolds

Background Optimal implantation results of bioresorbable scaffolds (BRS) are typically assumed to require postdilatation with non‐compliant (NC) balloons to achieve full scaffold apposition and minimize event rates. We systematically evaluated the mechanical effect of NC balloon postdilatation on magnesium‐based BRS (Magmaris®, Biotronik AG, Bülach, Switzerland) in vivo. Methods In 35 patients, 40 Magmaris® BRS were implanted to treat 37 de novo coronary artery stenoses. A systematic implantation protocol was followed. After appropriately sized NC balloon predilatation (1:1:1 vessel:balloon:scaffold ratio), Magmaris® BRS were implanted with a pressure of 10 atm, followed by NC balloon postdilatation at nominal BRS size (standardized at 16 atm). OCT was performed before and after postdilatation and OCT images were analyzed at a spacing of 0.2 mm to measure BRS dimensions and determine apposition as well as to detect strut fractures. Results PCI with Magmaris® BRS (mean diameter: 3.21 ± 0.32 mm; mean length: 20 ± 4 mm) was successful in all cases, in one case a non‐flow‐limiting distal edge dissection occurred after implantation and before postdilatation. NC balloon postdilatation led to significantly larger mean scaffold diameter (3.21 ± 0.32 mm vs. 2.80 ± 0.39 mm, P < 0.001), abluminal scaffold area (7.92 ± 1.43 mm 2 vs. 6.72 ± 1.28 mm 2 , P < 0.001) and lumen area (7.58 ± 1.1 mm 2 vs. 6.83 ± 1.12 mm 2 , P < 0.001). Incomplete scaffold apposition area was significantly lower if postdilatation was performed (0.01 ± 0.04 mm 2 vs. 0.17 ± 0.11 mm 2 , P < 0.001). Strut fractures could neither be observed before nor after postdilatation. Conclusion NC balloon postdilatation of Magmaris® BRS is required to achieve optimal expansion. It significantly reduces malapposition and can safely be performed without relevant rates of strut fracture.