Evaluation of a Bioabsorbable Self-Expandable Vein Stent-Base Made of Poly(l-lactide) In Vitro and In Vivo

Mechanical characteristics of venous stents to overcome challenges of venous outflow obstruction

BACKGROUND

Many challenges posed by the venous outflow obstruction (VOO) are unique to the venous system which require specific mechanical characteristics of stents to overcome them. Therefore, this article aims to review and discuss these challenges and the stent mechanical characteristics required to overcome them.

METHODS

A literature search was performed with Pubmed with the terms "mechanical characteristics of venous stents" and "mechanical properties of venous stents".

RESULTS

The venous system poses unique anatomical, physiological and pathological challenges when compared to the arterial counterpart. Several mechanical characteristics specific to venous stents which include the size, inherent forces, and flexibility are important to overcome these unique challenges when treating VOO. The most important stent inherent forces for venous stents include the chronic outward force, radial resistive force, and crush resistance. Various stent materials and designs, particularly laser-cut versus braided-structure stents, and open-cell versus closed-cell stents, determine the mechanical characteristics including the inherent forces of the venous stents. The desired mechanical characteristics of stents needed to overcome the venous system challenges often in conflict or with opposing effects. Therefore, it is important to fine adjust and optimise these characteristics.

CONCLUSIONS

There are many anatomical, physiological, and pathological challenges unique to the venous system which need to be overcome by the stent system mechanically when treating VOO. Therefore, dedicated venous stents with optimal mechanical characteristics are being developed with different designs and properties to treat VOO. Further research and innovations are needed to improve the stent technology that targets the venous system specifically.

Stent-mediated gene and drug delivery for cardiovascular disease and cancer: A brief insight

This review concisely recapitulates the different existing modes of stent-mediated gene/drug delivery, their considerable advancement in clinical trials and a rationale for other merging new technologies such as nanotechnology and microRNA-based therapeutics, in addition to addressing the limitations in each of these perpetual stent platforms. Over the past decade, stent-mediated gene/drug delivery has materialized as a hopeful alternative for cardiovascular disease and cancer in contrast to routine conventional treatment modalities. Regardless of the phenomenal recent developments achieved by coronary interventions and cancer therapies that employ gene and drug-eluting stents, practical hurdles still remain a challenge. The present review highlights the limitations that each of the existing stent-based gene/drug delivery system encompasses and therefore provides a vision for the future with respect to discovering an ideal stent therapeutic platform that would circumvent all the practical hurdles witnessed with the existing technology. Further study of the improvisation of next-generation drug-eluting stents has helped to overcome the issue of restenosis to some extent. However, current stent formulations fall short of the anticipated clinically meaningful outcomes and there is an explicit need for more randomized trials aiming to further evaluate stent platforms in favour of enhanced safety and clinical value. Gene-eluting stents may hold promise in contributing new ideas for stent-based prevention of in-stent restenosis through genetic interventions by capitalizing on a wide variety of molecular targets. Therefore, the central consideration directs us toward finding an ideal stent therapeutic platform that would tackle all of the gaps in the existing technology.