Intravital Microscopy of Pulmonary Microcirculation After Single Lung Transplantation in Pigs

Following reperfusion, oxygenation of pulmonary venous blood was excellent. However, blood flow distribution was significantly reduced to the transplanted lung compared with the native right recipient lung. Pulmonary vascular resistance was significantly increased, dropping from 3500 to 1000 dynes × s × cm−5 during reperfusion compared to a value of 500 for the native right lung. The pulmonary microcirculation showed a significant number of no-reflow areas with extremely reduced red blood cell velocities. Greater than 90% of microvessels (<30 μm) showed velocities below 0.1 mm/sec. In conclusion, microvascular injury seems to be a major pathogeneic factor for the development reperfusion failure. Quantification of alterations within the microvasculature may shed light on various treatment modalities that reduce perfusion failure.