Decellularization and characterization of camel pericardium as a new scaffold for tissue engineering and regenerative medicine

BACKGROUND

Valvular heart diseases (VHDs) have become prevalent in populations due to aging. Application of different biomaterials for cardiac valve regeneration and repair holds a great promise for treatment of VHD. Aortic valve replacement using tissue-engineered xenografts is a considered approach, and the pericardium of different species such as porcine and bovine has been studied over the last few years. It has been suggested that the animal origin can affect the outcomes of replacement.

METHODS

So, herein, we at first decellularized and characterized the camel pericardium (dCP), then characterized dCP with H&E staining, in vitro and in vivo biocompatibility and mechanical tests and compared it with decellularized bovine pericardium (dBP), to describe the potency of dCP as a new xenograft and bio scaffold.

RESULTS

The histological assays indicated less decluttering and extracellular matrix damage in dCP after decellularization compared to the dBP also dCP had higher Young Modulus (105.11), and yield stress (1.57  ±  0.45). We observed more blood vessels and also less inflammatory cells in the dCP sections after implantation.

CONCLUSIONS

In conclusion, the results of this study showed that the dCP has good capabilities not only for use in VHD treatment but also for other applications in tissue engineering and regenerative medicine.

Aortic valve neocuspidization using the Ozaki technique: A meta-analysis of reconstructed patient-level data

BACKGROUND

Aortic valve neocuspidization using the Ozaki technique has shown promising results both in adults and children.

METHODS

A systematic search of the PubMed and Cochrane databases was performed up to November 13, 2021. Individual patient data were reconstructed and analyzed from the Kaplan-Meier curves of all eligible studies for time-to-event outcomes.

RESULTS

We included a total of 22 studies reporting on 1,891 patients that underwent Ozaki reconstruction. Mean age at the time of surgery was 43.2 ± 24.5 years (65 ± 12.3 years for adult patients and 12.3 ± 3.8 years for pediatric patients). The most common indication was aortic stenosis (46.4%, 95% CI 34.1-58.6). Mean cross-clamp and cardiopulmonary bypass duration were 106.8 ± 24.8 minutes and 135.2 ± 35.1 minutes, respectively. Permanent pacemaker was implanted in 0.7% (95% CI 0.4-1.2) of the patients. At discharge, mean effective orifice area was 2.1 ± 0.5 cm²/m². At latest follow-up, peak gradient was 15.7 ± 7.4 mm Hg and only 0.25% (95% CI 0-2.3) had moderate aortic insufficiency. In-hospital mortality was 0.7% (95% CI 0.1-1.7). Late mortality was 1.9% during a mean follow-up of 38.1 ± 23.8 months. One-year, 3-year, and 5-year freedom from reoperation rates were 98.0 %, 97.0 % and 96.5%, respectively. More than half of the reoperations were due to infective endocarditis (51.5%, 95% CI 18.3-84.0). In our cohort, the risk of endocarditis per patient per year was 0.5%.

CONCLUSIONS

The midterm outcomes of the Ozaki procedure are excellent in terms of hemodynamics, survival, and freedom from reoperation. Acquiring long-term follow-up will help solidify this technique in the cardiac surgery armamentarium.

Aortic valve neocuspidization using autologous versus bovine pericardium: Ozaki versus Batista

BACKGROUND

The average living age of the population is constantly increasing and so is the incidence and prevalence of aortic valve disease. Surgical aortic valve replacement (SAVR) is the current gold standard treatment. Nevertheless, the use of prosthetic valves in SAVR is associated with issues that impact patients' quality of life. Aortic valve neocuspidization (AV Neo) offers a means to solve this dilemma by minimizing foreign valve tissue. AV Neo can either be performed using glutaraldehyde-treated autologous pericardium (Ozaki procedure) or bovine pericardium (Batista procedure).

AIMS

This commentary aims to discuss the recent study by Chan and colleagues which highlighted the surgical approach, clinical outcomes, and limitations of the Ozaki procedure, and compare this to the Batista procedure.

METHODS

A comprehensive literature search was performed using multiple electronic databases including PubMed, Ovid, Embase, and Scopus to collate the relevant research evidence.

RESULTS

Although the Ozaki procedure can achieve favorable results whilst mainly avoiding the need for life-long oral anticoagulation with mechanical valves, it still has several limitations that may hinder results. AV Neo using glutaraldehyde-treated bovine pericardium, developed by pioneer cardiac surgeon Dr. Randas J. Vilela Batista, yields superior clinical outcomes to Ozaki's, including excellent survival, lower complications, and minimal need for reoperation as well as shorter operative times.

CONCLUSION

AV Neo offers a means to perform SAVR whilst escaping the prosthetic valve issues. However, the Batista procedure has shown beyond doubt that it can be considered the superior approach for AV Neo over the Ozaki procedure.

Understanding aortic valve repair through Ozaki procedure: A review of literature evidence

BACKGROUND

Aortic valve neocuspidization (AV Neo) using glutaraldehyde-treated autologous pericardium was first reported by Ozaki et al. in 2007. This technique has become an alternative to tissue and mechanical valve in selected patients as long-term anticoagulation is not required and shows promising midterm results and durability.

METHOD

A comprehensive search was performed on the major database using the search terms "Ozaki technique" AND "Aortic Valve Neocuspidization" AND "AV Neocuspidization" AND "Autologous pericardium" AND "glutaraldehyde-treated autologous pericardium." Articles up to August 1st, 2021 were included in this study.

RESULTS

A total of nine studies with a total of 1342 patients were included. The mean age was 67.36 and 54.23% were male. 66.32% and 23.92% of patients had aortic stenosis and aortic regurgitation, respectively. 66% of patients had a native tricuspid aortic valve (AV) and 31.37% of patients' native AV was bicuspid. Three studies reported their experience performing AV Neo via ministernotomy.

CONCLUSION

AV Neo can be a suitable alternative to surgical AV replacement in selected patients. The short- and midterm outcomes are comparable without the need for long-term oral anticoagulation. Long-term follow-up data are required for this novel approach to be widely adopted.

Aortic Valve Neocuspidization Using Autologous Pericardium (Ozaki Procedure): an Alternative to Aortic Valve Replacement in Adult Cardiac Surgery?

Purpose of the Review

The aim of this article is to describe the technique of aortic valve neocuspidization using autologous pericardium (AVNeo, “OZAKI procedure”) in adult cardiac surgery, to analyze recent findings, and to discuss benefits and limitations of this technique.

Recent Findings

Potential benefits of this technique include excellent hemodynamic performances, minimal use of foreign material, low rates of permanent pacemaker implantation, and omission of oral anticoagulation. However, data regarding the durability of the procedure are hitherto limited, and the procedure is associated with a higher complexity compared to aortic valve replacement.

Summary

AVNeo using autologous pericardium in adult cardiac surgery is a promising technique providing several benefits. However, there is a major unmet need for more data, especially regarding long-term durability. Thus, based on currently available data, we recommend careful patient selection within the heart team and shared decision-making with the informed patient.

[Redo aortic valve reconstruction as saving surgery in a patient with severe rheumatoid cardiac disease]

The combination of aortic regurgitation, rheumatoid aortitis, and subaortic stenosis is rare in patients with rheumatoid arthritis. Moreover, the surgical treatment of these entities can be challenging and with non-adequate results. We report a case of a patient with severe aortic regurgitation, inaccessible aortic root secondary to rheumatoid aortitis, and severe subaortic stenosis initially treated by aortic valve replacement. We reoperated the patient due to acute prosthetic valve failure by an aortic valve reconstruction using bovine pericardium and Ozaki technique with good outcomes.

Mapping of bovine pericardium to enable a standardized acquirement of material for medical implants

OBJECTIVES

Bovine pericardium - native, fixed as well as decellularized - is one of the most common implant materials in modern cardiovascular surgery. Although used in everyday procedures, there are no recommendations in regard to which part of the pericardium to prefer. It was the aim of this study, to identify areas of the pericardium with consistent properties and high durability.

METHODS

Fresh bovine pericardia were collected from a local slaughterhouse. The native pericardia were analyzed at 140 spots in regard to thickness and fiber orientation. Based on these results, five promising areas were selected for further evaluation. The pericardia were decellularized with detergents (0.5% sodiumdesoxycholate/0.5% sodiumdodecylsulfate) and subsequently incubated in DNAse. The two investigation groups native und DC consisted of 20 samples each. The efficiency of the decellularization was evaluated by DNA quantification, as well as DAPI and H&E staining. Biomechanical properties were determined using uniaxial tensile tests. To evaluate the microstructure, scanning electron microscopy, Picrosirius Red- and Movat's Pentachrome staining were utilized. To assess the long-term durability, patches were tested in a high-cycle system for a duration equaling the stress of three months in-vivo. Commercially available, fixed pericardium patches served as control group.

RESULTS

Only a limited part of the pericardium showed a homogenous and usable thickness. The decellularization removed all cell nuclei, proven by negative DAPI and H&E staining, and also significantly reduced the DNA amount by 84%. The mechanical testing revealed that two investigated areas had an inconsistent tensile strength. Microscopical observations showed that the integrity of the extracellular matrix did not suffer by the decellularization procedure. During the long-term testing, most of the pericardia slowly lost tautness, though none of them got measurably damaged. Especially one area showed no decline of tensile strength after durability testing at all. Decellularized patches and fixed patches achieved comparable results in mechanical testing and microscopical evaluation after the durability testing.

CONCLUSION

We could clearly document significant, location-based differences within single pericardia. Only one area showed consistent properties and a high durability. We highly recommend taking this into account for future implant material selections.

Quality of life in sexagenarians after aortic biological vs mechanical valve replacement: a single-center study in China

Objective

This article aimed to study the quality of life and anxiety of sexagenarian patients who underwent aortic biological vs mechanical valve replacement in a single center in China.

Methods

The clinical data of 78 patients aged 60 to 70 years who underwent aortic prosthetic valve replacement were retrospectively analyzed in our hospital from June 2017 to February 2018. Patients were divided into two groups depending on the type of prosthetic valve they received (biological valve group vs mechanical valve group). The SF-36 was completed by all patients at discharge and at one-year follow-up, and the cardiac anxiety questionnaire (CAQ) was also completed at one-year follow-up.

Results

There was no statistically significant difference between the two groups in general clinical data or SF-36 score at discharge. However, at one-year follow-up, the SF-36 scores were significantly higher in the biological valve group than in the mechanical valve group, and the CAQ scores in fear and anxiety, avoidance and attention in the mechanical valve group were significantly higher than those in the biological valve group.

Conclusions

Based on the postoperative quality of life and anxiety scores of sexagenarian patients who underwent biological vs mechanical valve replacement in this study, a biological valve has more value than a mechanical valve for sexagenarians undergoing aortic valve replacement.