Partial pressure of oxygen-guided adrenal venous sampling in primary aldosteronism

Adrenal venous sampling (AVS) plays a pivotal role in treatment optimization for primary aldosteronism (PA) to minimize cardiovascular risks. However, technical difficulties often hinder accurate cannulation to the adrenal veins (AVs).

This study aimed to explore the distribution of partial pressure of oxygen (pO2) in the AV and neighboring veins, inspired by our awareness of the lighter red color of adrenal venous blood than the others.

We enrolled 179 PA patients who underwent AVS from 2021 to 2024. During AVS, we collected residual blood samples from bilateral AV, hepatic (HV), inferior phrenic, and external iliac veins for blood gas analysis. Statistical analysis was conducted to evaluate pO2 distributions and its associations with clinical parameters.

Among 179 patients examined, 168 received oxygen supplementation during AVS and in those cases, the pO2 levels were significantly higher in the bilateral AVs than in the HV and inferior phrenic veins at baseline, whereas the levels of partial pressure of carbon dioxide were lower. Following cosyntropin stimulation, the pO2 levels in the AVs decreased but distribution patterns across the examined veins remained similar. The pO2 evaluation provided highly accurate identification of AVs both before and after cosyntropin stimulation.

This is the first study to examine the pO2 dynamics in the human AV and non-AVs, demonstrating its potential to improve AVS cannulation success rates. Our findings also presented the oxygen consumption in the adrenal glands for steroidogenesis. The pO2 measurement is a faster, easier and less-expensive tool enhancing AVS techniques.