Hypoxic Perfusion of the Pulmonary Artery Vessel Wall Causes Increased Pulmonary Arterial Pressure in the Isolated Pig Lung in the Organ Care System

Background: Vasa vasorum (VV) cannot only be found in systemic arteries but also in pulmonary arteries, in which they originate from the bronchial arteries. Subject of this study is the influence of bronchial artery blood supply on the muscle tone of pulmonary artery vessel walls and resulting changes in pulmonary artery pressure (PAP). We hypothesized that hypoxic perfusion of the bronchial artery (BA), and therefore of the VV of the pulmonary artery (PA), leads to pulmonary artery smooth muscle cell dysfunction, causing an increase in PAP.

Method: Lungs from six domestic pigs were ventilated and perfused ex vivo in the OCS system (Transmedics, Andover, MA). In addition, hypoxic or normoxic perfusion of the BA circulation was performed via an aortic pouch, which was formed around the outlet of the BA. PAP under physiological conditions was compared with PAP under hypoxic perfusion of BA. The experiment started under physiological conditions in steady state (sts1), followed by isolated hypoxic perfusion (h1) as the first intervention (int1). This was followed by a second intervention (int2), consistent of a steady state (sts2) and a second isolated hypoxic perfusion (h2) of the BA.

Results: The mean systolic PAP was significantly higher in the hypoxic group (h1+2) compared with the steady state group (sts1+2) (24 ± 4.58 mm Hg and 18.9 ± 2.16 mm Hg, p < 0.05).

Conclusion: Isolated perfusion of the BA in the ex vivo setting, including targeted perfusion of the PA wall- microvasculature is feasible. Our data demonstrate that the state of oxygenation in BA perfusion directs PAP. Results indicate that a low oxygen saturation of the PA vessel wall increases PAP, suggesting an entirely new pathobiology in PHT, including its hypoxic variant.

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Artikel online veröffentlicht:
28. Januar 2023