Time dependent modifications in arterial flow in a transplanted pulmonary lobe

Area of Science:

• Cardiovascular Physiology
• Transplantation Immunology
• Surgical Research

Background:

• Pulmonary arterial flow dynamics are critical for transplanted lung viability.
• Graft rejection is a significant complication impacting graft function.
• Non-invasive or minimally invasive monitoring methods are needed to assess graft health.

Purpose of the Study:

• To investigate pulmonary arterial flow changes in transplanted lungs using an implanted ultrasonic flowmeter.
• To correlate these flow changes with graft rejection and functional outcomes.
• To directly observe and quantify the presence of precapillary shunts in rejecting lung grafts.

Main Methods:

• Implantation of an ultrasonic flowmeter in the pulmonary artery of transplanted lungs in an animal model.
• Monitoring of pulmonary arterial flow parameters over time.
• Correlation of flow data with histological evidence of rejection and physiological measurements.
• Direct visualization and assessment of precapillary shunts.

Main Results:

• Confirmed that untreated graft rejection leads to increased peripheral resistances and progressive decline in pulmonary arterial flow.
• Demonstrated the existence of significant precapillary shunts in rejecting lung grafts via direct observation.
• Observed that these shunts can lead to severe functional disorders and potentially graft failure.

Conclusions:

• Implanted ultrasonic flowmetry is a valuable tool for monitoring pulmonary arterial flow in transplanted lungs.
• Graft rejection significantly impairs pulmonary hemodynamics, characterized by increased resistance and reduced flow.
• Precapillary shunts are a critical pathophysiological finding in rejecting lung grafts and can be a cause of mortality.