A Novel In Silico–Ex Vivo Model for Correlating Coating Transfer to Tissue with Local Drug-Coated Balloon-Vessel Contact Pressures

Abstract

Drug-coated balloons (DCBs) aim to deliver drug-loaded surface coating upon inflation at specific vascular sites, yet the role of inflation pressure remains to be defined. We implement a new approach combining ex vivo stamping experiments with in silico simulations to study acute coating transfer by commercial DCBs. This methodology comprises 3 essential pillars: (I) DCB resin inflation and slicing into cylindrical segments for subsequent stamping onto porcine-excised tissue, (II) Numerical inflation of a full DCB replica in an idealized porcine vessel to predict in vivo interfacial contact pressures (CPs) and subsequent interfacial-level numerical stamping to calculate appropriate benchtop forces that recreate these in vivo CP values, and (III) ex vivo stamping experiments and optical analysis of the stamped surfaces (DCB segment and arterial tissue), using a standard high-resolution camera to visualize coating. High-performance liquid chromatography (HPLC) was employed as a validated assay for quantifying drug in tissue samples post-stamping. HPLC analysis revealed a significant correlation with image processing, confirming the validity of the optical method as a tool to quantify DCB coating. Image and HPLC analysis revealed a statistically significant twofold rise in coating area and drug content to tissue, respectively, when the average CP roughly doubled (0.16–0.35 atm) and a non-statistically significant increase in coating area and drug content with a further rough doubling of average CP (0.35 to 0.75 atm). Imaging of DCB segments pre- and post-stamping showed transfer of partial coating thickness at low CP, contrasting with complete transfer at high CP at the same site. 3D confocal images of DCB surfaces revealed variable thickness in the transferred coating. This study introduces a comprehensive methodology for evaluating the efficacy of commercial DCB coating transfer to arterial tissue—a crucial precursor to drug elution studies—while minimizing the number of DCBs needed and improving variable control and realism.