Biohybrid elastin-like venous valve with potential for in situ tissue engineering

Chronic venous insufficiency (CVI) is a leading vascular disease whose clinical manifestations include varicose veins, edemas, venous ulcers, and venous hypertension, among others. Therapies targeting this medical issue are scarce, and so far, no single venous valve prosthesis is clinically available. Herein, we have designed a bi-leaflet transcatheter venous valve that consists of (i) elastin-like recombinamers, (ii) a textile mesh reinforcement, and (iii) a bioabsorbable magnesium stent structure. Mechanical characterization of the resulting biohybrid elastin-like venous valves (EVV) showed an anisotropic behavior equivalent to the native bovine saphenous vein valves and mechanical strength suitable for vascular implantation. The EVV also featured minimal hemolysis and platelet adhesion, besides actively supporting endothelialization in vitro, thus setting the basis for its application as an in situ tissue engineering implant. In addition, the hydrodynamic testing in a pulsatile bioreactor demonstrated excellent hemodynamic valve performance, with minimal regurgitation (<10%) and pressure drop (<5 mmHg). No stagnation points were detected and an in vitro simulated transcatheter delivery showed the ability of the venous valve to withstand the implantation procedure. These results present a promising concept of a biohybrid transcatheter venous valve as an off-the-shelf implant, with great potential to provide clinical solutions for CVI treatment.

Advances in Engineering Venous Valves: The Pursuit of a Definite Solution for Chronic Venous Disease

Native venous valves enable proper return of blood to the heart. Under pathological conditions (e.g., chronic venous insufficiency), venous valves malfunction and fail to prevent backward flow. Clinically, this can result in painful swelling, varicose veins, edema, and skin ulcerations leading to a chronic wound situation. Surgical correction of venous valves has proven to drastically reduce these symptoms. However, the absence of intact leaflets in many patients limits the applicability of this strategy. In this context, the development of venous valve replacements represents an appealing approach. Despite acceptable results in animal models, no venous valve has succeeded in clinical trials, and so far no single prosthetic venous valve is commercially available. This calls for advanced materials and fabrication approaches to develop clinically relevant venous valves able to restore natural flow conditions in the venous circulation. In this study, we critically discuss the approaches attempted in the last years, and we highlight the potential of tissue engineering to offer new avenues for valve fabrication. Impact statement Venous valves prosthesis offer the potential to restore normal venous flow, and to improve the prospect of patients that suffer from chronic venous disease. Current venous valve replacements are associated with poor outcomes. A deeper understanding of the approaches attempted so far is essential to establish the next steps toward valve development, and importantly, tissue engineering constitutes a unique toolbox to advance in this quest.

Prosthetic venous valves: Short history and advancements from 2012 to 2020

Chronic Venous Disease is estimated at 83.6% of the global population. Patients experience pain, discomfort and severe complications with few effective therapies being available. Current strategies for the treatment of malfunctioning venous valves are invasive with a high recurrence rate. A prosthetic venous valve replacement is imminent, possibly providing better outcomes and improved general quality of life. In this review, prosthetic venous valves history is presented and assesses the advantages and disadvantages of developed venous valves. Articles that discussed potential designs of prosthetic venous valves were examined. A systematic search produced thirty-five papers fitting the inclusion criteria. Our understanding of the ideal abilities required in prosthetic valves has evolved. Developed valves are reported for regurgitation, migration and leakage. Issues have been resolved, but we are still away from the ideal valve. Improvements within the last eight years provided information on the importance of sinuses and prosthetic to venous wall-size mismatch.

Present and future options for treatment of infrainguinal deep vein disease

OBJECTIVE

Management of chronic deep vein disease focuses on the alleviation of reflux and obstruction. For the suprainguinal veins, the main underlying pathologic process is obstruction, which has been recognized as a significant contributor to chronic venous insufficiency. This is currently being addressed with venous stenting and the development of dedicated stents designed for this segment of the venous system. Treatment of the femoropopliteal vein (FPV) is far more challenging because of the idiosyncratic anatomy, the hemodynamic physiology, and the technical aspects of size mismatch and valve flow dynamics in managing deep venous reflux. This review article discusses traditional and emerging technologies to treat infrainguinal disease.

METHODS

Previous and current articles addressing this issue were reviewed. Emphasis was placed on emerging techniques and technologies.

RESULTS

Significant bench work, in vitro and in vivo studies, have been conducted over the last 40 years addressing the issue of infrainguinal reflux and obstruction. Historically, open procedures to address FPV reflux and obstruction have had variable success in a few centers around the world. The significant increase of emerging endovascular therapies may allow more appropriate, reproducible, widespread treatment of infrainguinal deep venous disease.

CONCLUSIONS

Adequate and durable therapies for infrainguinal venous disease represent one of the greatest challenges for a vein specialist. Recently, a cluster of interest and techniques/technologies have been developed. The endovascular management of arterial disease is mature. The endovenous management of infrainguinal disease is on the cusp of meaningful innovation. The purpose of this evidence summary is to describe the options for the management of chronic FPV disease, with emphasis on emerging technologies and techniques.