Cardiac Loading using Passive Left Atrial Pressurization and Passive Afterload for Graft Assessment

Area of Science:

• Cardiovascular Surgery
• Organ Transplantation
• Biomedical Engineering

Background:

• Normothermic machine perfusion (NMP) is crucial for organ preservation in transplantation.
• Current NMP graft evaluation relies on limited metabolic trends, lacking objective functional assessment.
• Hemodynamic measurements from left ventricular loading offer potential objective parameters for graft evaluation.

Purpose of the Study:

• To develop an effective method for incorporating left ventricular loading into established Langendorff perfusion systems.
• To demonstrate the feasibility of passive left atrial pressurization for cardiac loading.
• To capture functional cardiac metrics during perfusion for improved graft assessment.

Main Methods:

• Modification of Langendorff perfusion systems with an additional reservoir for loading capabilities.
• Implementation of passive left atrial pressurization for controlled cardiac loading.
• Integration of a passive Windkessel afterload for enhanced diastolic perfusion.
• Measurement of functional metrics: left ventricular pulse pressure, contractility, and relaxation.

Main Results:

• Successful incorporation of loading capabilities into a standard Langendorff system.
• Demonstrated feasibility of passive left atrial pressurization for cardiac loading.
• Capability to capture key functional metrics during cardiac loading.
• Identification of cardiac graft deficiencies after prolonged preservation (>6 hours).

Conclusions:

• The developed protocol provides an effective and simple method for assessing cardiac grafts during NMP.
• Passive left atrial pressurization is a feasible approach for cardiac loading in perfusion systems.
• This method allows for objective functional assessment of heart grafts, potentially improving transplant success rates.