Designing Better Cardiovascular Stent Materials: A Learning Curve

Abstract

Cardiovascular stents are life‐saving devices and one of the top ten medical breakthroughs of the 21st century. Decades of research and clinical trials have taught us about the effects of material (metal or polymer), design (geometry, strut thickness, and the number of connectors), and drug‐elution on vasculature mechanics, hemocompatibility, biocompatibility, and patient health. Recently developed novel bioresorbable stents are intended to overcome common issues of chronic inflammation, in‐stent restenosis, and stent thrombosis associated with permanent stents, but there is still much to learn. Increased knowledge and advanced methods in material processing have led to new stent formulations aimed at improving the performance of their predecessors but often comes with potential tradeoffs. This review aims to discuss the advantages and disadvantages of stent material interactions with the host within five areas of contrasting characteristics, such as 1) metal or polymer, 2) bioresorbable or permanent, 3) drug elution or no drug elution, 4) bare or surface‐modified, and 5) self‐expanding or balloon‐expanding perspectives, as they relate to pre‐clinical and clinical outcomes and concludes with directions for future studies.

Cardiovascular Stents: A Review of Past, Current, and Emerging Devices

“…Therefore, cardiovascular stents are life-saving devices, rightfully included in the top ten medical breakthroughs of our century [ 18 ]. From a constructive point of view, stents are small, complex, cylindrically shaped hollow structures formed into a sequential ring construction comprising a series of struts and connecting elements [ 13 , 15 , 19 ].…”

“…The decades of research and clinical trials in this field have resulted in various stent designs involving diverse materials, from which doctors can choose the appropriate device depending on the local deposition of plaque and fatty substances and the potential side effects [ 15 , 18 ].…”

3D Printing of Polymeric Bioresorbable Stents: A Strategy to Improve Both Cellular Compatibility and Mechanical Properties

“…Due to the mechanical properties of metals, BMS stents have an increased radial strength that allows robust mechanical support to the vessel wall with a thin strut. Devices with reduced struts are known for having a reduced crossing profile, which induces less tissue injury and less disruption in the blood flow [ 36 ]. Nevertheless, introducing a permanent metallic framework triggers inflammatory responses, such as neointimal hyperplasia, that lead to the artery’s reblockage and the activation of the coagulation cascade [ 13 ].…”

“…These events can be associated with the metallic ions released from the stainless steel (316LSS) and cobalt–chromium (CoCr) alloys through the presence of crevice, pitting, and stress corrosion cracking. For instance, the release of nickel, molybdenum, and chromium ions can trigger genotoxic and mutagenic events and activate allergic responses [ 36 ]. As a result, drug-eluting stents emerged to overcome the undesirable effects of BMS implantation [ 8 ].…”

Applying Principles of Regenerative Medicine to Vascular Stent Development

“…For a more detailed summary of BVS, please refer to additional reviews on the topic ( Omar and Kumbhani, 2019 ; Cockerill et al, 2021 ; Yuan et al, 2022 ). In brief, researchers in academia and industry share the dream of a bioabsorbable scaffold that delivers therapeutic and regenerative agents to the vessel, maintains radial strength for a sufficient period of time (>6 months), and then disappears when therapy and regeneration jobs are done.…”