Does anyone know what this is?

Jamie • 19 💁🏼‍♀️ diabetic 💉 Kyden James 12-24-18 👶🏼💙 4-15-2017 💑❤️

I just got an ultrasound today and they told me my sons right pulmonary artery is prominent. Can anyone explain to me what that means? They didn’t say much about it just scheduled me three more appointments ASAP and told me to call some cardiologist..