A thermal-fluidic-driven, retrievable shape memory polymer colonic stent: design and multi-objective optimization

The increasing clinical demands for temporary colonic interventions – such as bridge-to-surgery decompression and benign stricture management – require stents that balance compact delivery, stable support, and atraumatic retrieval. To address these conflicting needs, we propose a novel thermal-fluidic-driven, retrievable, variable-stiffness shape memory polymer (SMP) stent. The helical device features an integrated closed-loop fluid lumen, utilizing circulated water for rapid deployment, instantaneous structural fixation via active cooling, and subsequent softening for safe extraction. To explore the underlying design rules and navigate the inherent geometric trade-offs, we established a systematic multi-objective optimization framework. A Design of Experiments (DoE) strategy was employed to guide the finite element (FE) simulations, which assessed four functional objectives: minimizing intestinal stress, maximizing anti-migration force, maximizing radial support, and minimizing retrieval force. Using a high-fidelity surrogate model combining response surface methodology (RSM) and Gaussian process regression (GPR), we conducted NSGA-II optimization to identify a Pareto-optimal front. These non-dominated designs were clustered into seven families, providing tailored geometric solutions for distinct clinical needs. Experimental validation confirmed the framework’s accuracy, offering a robust design paradigm for next-generation, transient intraluminal devices.