EVLP (Ex-vivo Lung Perfusion Technique) - An Overview

What Is Ex Vivo Lung Perfusion (Evlp)?

Ex vivo lung perfusion (EVLP) refers to a technique used in the field of transplantation medicine, specifically in the context of lung transplantation. Lung transplantation represents the sole therapeutic intervention capable of preserving the lives of individuals afflicted with specific forms of terminal lung ailments. However, the procedure has limited availability because not all donor lungs are safe for transplantation. The insufficiency of available donor lungs leads to a mortality rate of 20 percent among individuals awaiting lung transplantation.

Ex vivo lung perfusion (EVLP) is a novel therapeutic approach to treating donor lungs outside the human body before transplantation. This technique enhances the quality of the organ and renders previously unsuitable lungs suitable for transplantation. The primary objective of the Ex vivo lung perfusion program is to enhance the availability of donor lungs and broaden the reach of this life-saving treatment to a larger population of transplant recipients.

What Are the Potential Risks Associated With Ex Vivo Lung Perfusion?

The objective is to enhance the safety and efficacy of transplantation procedures. Loyola's surgeons are expanding the availability of life-saving treatment options to more patients by utilizing ex vivo lung perfusion. Every surgical procedure carries inherent risks. When considering lung transplantation following ex vivo lung perfusion, potential risks that should be taken into consideration:

• Premature mortality/death.

• Infection.

• Primary graft dysfunction (PGD) is a condition that occurs following organ transplantation, characterized by the dysfunction of the transplanted organ shortly after the procedure.

• Impaired pulmonary function or weak respiratory capacity.

What Are the Principles Of EVLP?

The action of the gas exchange mechanism during normal lung blood circulation is the basic idea behind the EVLP technology.

• Deoxygenated perfusion fluid is delivered into the lung to ensure it can be oxygenated as part of determining how well the isolated lung performs its job by actual time tracking of lung function and blood gas markers.

• The circulatory fluid delivered to the isolated lung during mechanical perfusion can be further purified by adding a microemboli filter and a leukocyte filter to the mechanical perfusion system. This will improve the perfusion effect and allow the system to function more effectively than in previous instances.

• The ability of EVLP to effectively sustain the respiratory function of isolated lungs is a significant benefit of the technique.

• The isolated lungs can continue to have healthy oxygen uptake and lung compliance.

• The EVLP ensures that a ventilation environment that is appropriate for the physiology of the respiratory tract is maintained, and the perfusion solution supplies the physiological components necessary for lung metabolism; it allows for optimal metabolic function in the lungs. Consequently, the lung that is separated from the rest of the respiratory system can maintain its respiratory function successfully under favorable conditions.

What Are the Mechanisms Occurring During the Process?

• During the EVLP, metabolic acidosis and electrolyte disturbance were seen in the two varieties of human non-acceptable donor lungs and the separate porcine/pig lungs.

• This was because both sets of lungs originated from animals. As the lungs were separated from the other parts of the body, there was a chance that they engaged in a higher amount of anaerobic respiration than the rest of the body experienced.

• The rate of glycolysis picked up, which led to an increase in the production of a substantial amount of lactic acid as a byproduct and, consequently, a decrease in the pH value.

• For the body to make up for the depletion of ion exchange between the inner and the outer layers of the cell membrane, the body must ingest extra sodium and potassium.

• This is the only way this loss can be compensated for; this will lead to an increase in the amount of sodium and potassium in the body.

• It has been noted that reducing the number of white blood cells taken from the EVLP system or reducing the number of cytokines removed will help alleviate electrolyte disturbance, stabilize the pH, and minimize the amount of pulmonary edema present.

What Are the Uses of The EVLP?

• Ex vivo lung perfusion (EVLP) is predominantly employed as a diagnostic tool for evaluating lungs deemed suboptimal for transplantation.

• EVLP can serve as more than just an evaluation tool by establishing physiological and regulated outcomes that have been observed in the domains of drug therapy (involves providing a patient one or more medications to treat or prevent an illness), gene therapy (a treatment, prevention method, or cure for an illness or medical issue that makes use of a gene or genes), stem cell therapy (a type of regenerative medicine that aims to repair damaged cells in the body by lowering inflammation and modifying the immune system, accomplished through stem cells.

• Due to this phenomena, stem cell therapy can effectively treat various medical diseases and medical gas therapy (administering gasses for curative reasons constitutes one of the most typical forms of respiratory care).

What Are the Future Opportunities Of Ex Vivo Lung Perfusion (EVLP)?

• EVLP provides logistical advantages due to the extension of preservation time without the extension of cold ischaemic time.

• The operations may be performed during normal working hours, and transplantation surgeries may be performed in series rather than parallel, the latter of which is only possible in a select number of centers.

• In addition to transplanting, several potential areas of innovation for EVLP have been identified. EVLP offers a robust and adaptable system for clinical trials in thoracic oncology.

• In the case of incurable cancers or multi-resistant lung infections, EVLP may be combined with autotransplantation to facilitate the delivery of chemotherapy and antimicrobials that are intolerably toxic.

• Bioengineering of lungs is an area that has a great deal of potential for the future. The effectiveness of EVLP as a method for decellularization and recellularization has already been demonstrated, and it has the potential to serve as a foundation for the evaluation and secure utilization of bioengineered lungs in the future as this field develops further.

Conclusion

Lung transplantation has already benefited significantly from the promising EVLP technology. The use of marginal donor lungs has boosted the number of lung transplants by using EVLP as an assessment tool. It enables the donor eligibility standards to be expanded—additionally, the potential for reconditioning donor lungs while in the EVLP circuit is promising. The lungs can undergo treatments or procedures to reduce their immunogenicity or make them transplantable. The EVLP systems are a foundation for expanding pulmonary and oncologic research and tissue bioengineering.