Tissue Valve Degeneration and Mechanical Valve Failure

Recent Advances in the Modification and Improvement of Bioprosthetic Heart Valves

Valvular heart disease (VHD) has become a burden and a growing public health problem in humans, causing significant morbidity and mortality worldwide. An increasing number of patients with severe VHD need to undergo heart valve replacement surgery, and artificial heart valves are in high demand. However, allogeneic valves from donors are lacking and cannot meet clinical practice needs. A mechanical heart valve can activate the coagulation pathway after contact with blood after implantation in the cardiovascular system, leading to thrombosis. Therefore, bioprosthetic heart valves (BHVs) are still a promising way to solve this problem. However, there are still challenges in the use of BHVs. For example, their longevity is still unsatisfactory due to the defects, such as thrombosis, structural valve degeneration, calcification, insufficient re-endothelialization, and the inflammatory response. Therefore, strategies and methods are needed to effectively improve the biocompatibility and longevity of BHVs. This review describes the recent research advances in BHVs and strategies to improve their biocompatibility and longevity.

Recent progress in functional modification and crosslinking of bioprosthetic heart valves

Valvular heart disease (VHD), clinically manifested as stenosis and regurgitation of native heart valve, is one of the most prevalent cardiovascular diseases with high mortality. Heart valve replacement surgery has been recognized as golden standard for the treatment of VHD. Owing to the clinical application of transcatheter heart valve replacement technic and the excellent hemodynamic performance of bioprosthetic heart valves (BHVs), implantation of BHVs has been increasing over recent years and gradually became the preferred choice for the treatment of VHD. However, BHVs might fail within 10-15 years due to structural valvular degeneration (SVD), which was greatly associated with drawbacks of glutaraldehyde crosslinked BHVs, including cytotoxicity, calcification, component degradation, mechanical failure, thrombosis and immune response. To prolong the service life of BHVs, much effort has been devoted to overcoming the drawbacks of BHVs and reducing the risk of SVD. In this review, we summarized and analyzed the research and progress on: (i) modification strategies based on glutaraldehyde crosslinked BHVs and (ii) nonglutaraldehyde crosslinking strategies for BHVs.

Causes and treatment strategies of unilateral leaflet escape of bileaflet mechanical prosthetic heart valves after surgery: a case series

BACKGROUND

During the eleven years from 2010 to 2021, preliminary statistics have shown that Fuwai Hospital completed 23,571 mechanical valve replacements for various types of valves, and 1139 mechanical valve replacements were performed in Guangyuan First People's Hospital. Only two patients developed valve leaflet escape, so valve leaflet escape is a rare postoperative complication.

CASE PRESENTATION

In 2010 and 2021, two patients were selected after they had unilateral leaflet escape after having mechanical valve replacements in Fuwai Hospital of Chinese Academy of Medical Sciences and Guangyuan First People's Hospital. Both patients underwent reoperations with the classic operation and the new bileaflet mechanical prosthetic heart valve was sutured. The treatment of detached single lobe and distal vessel was comprehensively determined, and the condition was treated according to the patient's symptoms, CT results, ultrasound results and other test results, as well as whether this detached lobe caused any abnormal hemodynamics of the distal vessel. The patient with mechanical aortic valve escape completed the 10-year follow-up, and patient with mechanical mitral valve escape completed the 3-month follow-up. there was no thrombosis or hematoma at the embolic site; the patient had no lower limb symptoms.

CONCLUSIONS

The reason for the leaflet escape may be related to the valve design and the leaflet material. If the detached leaflets are damaged and if the distal blood vessels are affected, simultaneous surgical treatment is required. Those patients whose vessels were not damaged by the valve lobe should be carefully monitored.

Long-term durability of a new surgical aortic valve: A 1 billion cycle in vitro study

Background

This study assessed the long-term hemodynamic functional performance of the new Inspiris Resilia aortic valve after accelerated wear testing (AWT).

Methods

Three 21-mm and 23-mm Inspiris valves were used for the AWT procedure. After 1 billion cycles (equivalent to 25 years), the valves' hemodynamic performance was compared with that of the corresponding zero-cycled condition. Next, 1 AWT cycled valve of each valve size was selected at random for particle image velocimetry (PIV) and leaflet kinematic tests, and the data were compared with data for an uncycled Inspiris Resilia aortic valve of the same size. PIV was used to quantitatively evaluate flow fields downstream of the valve. Valves were tested according to International Standards Organization 5840-2:2015 protocols.

Results

The 21-mm and 23-mm valves met the International Organization for Standardization (ISO) durability performance requirements to 1 billion cycles. The mean effective orifice areas for the 21-mm and 23-mm zero-cycled and 1 billion–cycled valves were 1.89 ± 0.02 cm² and 1.94 ± 0.01 cm², respectively (P < .05) and 2.3 ± 0.13 cm² and 2.40 ± 0.11 cm², respectively (P < .05). Flow characterization of the control valves and the study valves demonstrated similar flow characteristics. The velocity and shear stress fields were also similar in the control and study valves.

Conclusions

The Inspiris Resilia aortic valve demonstrated very good durability and hemodynamic performance after an equivalent of 25 years of simulated in vitro accelerated wear. The study valves exceeded 1 billion cycles of simulated wear, 5 times longer than the standard requirement for a tissue valve as stipulated in ISO 5840-2:2015.

Arginine-grafted porcine pericardium by copolymerization to improve cytocompatibility, hemocompatibility and anti-calcification properties of bioprosthetic heart valve materials

Bioprosthetic heart valves (BHVs) have been used widely due to the development of transcatheter heart valve replacement technology. However, glutaraldehyde crosslinked pericardium (GA), which is widely used as a leaflet...

Noncalcific Mechanisms of Bioprosthetic Structural Valve Degeneration

Bioprosthetic heart valves (BHVs) largely circumvent the need for long‐term anticoagulation compared with mechanical valves but are increasingly susceptible to deterioration and reduced durability with reoperation rates of ≈10% and 30% at 10 and 15 years, respectively. Structural valve degeneration is a common, unpreventable, and untreatable consequence of BHV implantation and is frequently characterized by leaflet calcification. However, 25% of BHV reoperations attributed to structural valve degeneration occur with minimal leaflet mineralization. This review discusses the noncalcific mechanisms of BHV structural valve degeneration, highlighting the putative roles and pathophysiological relationships between protein infiltration, glycation, oxidative and mechanical stress, and inflammation and the structural consequences for surgical and transcatheter BHVs.

Cross-Linking Porcine Pericardium by 3,4-Dihydroxybenzaldehyde: A Novel Method to Improve the Biocompatibility of Bioprosthetic Valve

Heart valve replacement is an effective therapy for patients with moderate to severe valvular stenosis or regurgitation. Most bioprosthetic heart valves applied clinically are based on cross-linking with glutaraldehyde (GLUT), but they have some drawbacks like high cytotoxicity, severe calcification, and poor hemocompatibility. In this study, we focused on enhancing the properties of bioprosthetic heart valves by cross-linking with 3,4-dihydroxybenzaldehyde (DHBA). The experiment results revealed that compared with GLUT cross-linked porcine pericardium (PP), the relative amount of platelets absorbed on the surface of DHBA cross-linked PP decreased from 0.294 ± 0.034 to 0.176 ± 0.028, and the activated partial thromboplastin time (APTT) increased from 9.9 ± 0.1 to 15.2 ± 0.1 s, indicating improved hemocompatibility. Moreover, anticalcification performance and cytocompatibility were greatly enhanced by DHBA cross-linking. In conclusion, the properties of bioprosthetic valves could be effectively improved by processing valves with a DHBA-based cross-linking method.

History, development and clinical perspectives of sutureless and rapid deployment surgical aortic valve replacement

Degenerative aortic stenosis is the most frequent valvular heart disease in industrialized countries. Conservative treatment may beneficially influence symptoms but is never successful. Surgical aortic valve replacement (SAVR) was the only recognized treatment option to provide substantially prolonged survival until 2008. Operative mortality of isolated SAVR has been reported as low as 0.5% to 1% in experienced institutions, while long-term survival is close to that observed in a control healthy population of similar age. A multitude of studies have demonstrated the beneficial effects of SAVR with regard to improvement in quality of life and physical performance in the majority of symptomatic patients. In the last decade, transcatheter aortic valve implantation (TAVI) has emerged as an equal treatment modality, first in patients with high surgical risk and more recently in patients with intermediate and low surgical risk. Paravalvular regurgitation and the higher rate of pacemaker implantation remain points of consideration. Additionally, the long-term durability of TAVI devices and occurrence of stroke late after TAVI require additional analyses. Sutureless (SU-SAVR) and rapid deployment valve (R-SAVR) were designed to simplify and accelerate a conventional or less invasive surgical procedure while allowing complete excision of the calcified native valve. From 3 different implants tested more than 10 to 15 years ago, only two are available on the market today: the Perceval^® valve from Liva Nova and the Intuity^® sutureless prosthesis from Edwards Lifesciences. There has been extensive experience with these two devices in previous years and the results obtained are comparable to those observed following the use of conventional implants. The sutureless devices may be of particular interest for more complex and combined surgical procedures. This review summarizes the sutureless (SU-SAVR) and rapid deployment valve technologies and presents a clinical outlook for the patient population managed with these devices.

TGF-β Signaling Promotes Tissue Formation during Cardiac Valve Regeneration in Adult Zebrafish

Cardiac valve disease can lead to severe cardiac dysfunction and is thus a frequent cause of morbidity and mortality. Its main treatment is valve replacement, which is currently greatly limited by the poor recellularization and tissue formation potential of the implanted valves. As we still lack suitable animal models to identify modulators of these processes, here we used adult zebrafish and found that, upon valve decellularization, they initiate a rapid regenerative program that leads to the formation of new functional valves. After injury, endothelial and kidney marrow-derived cells undergo cell cycle re-entry and differentiate into new extracellular matrix-secreting valve cells. The TGF-β signaling pathway promotes the regenerative process by enhancing progenitor cell proliferation as well as valve cell differentiation. These findings reveal a key role for TGF-β signaling in cardiac valve regeneration and establish the zebrafish as a model to identify and test factors promoting cardiac valve recellularization and growth.