A study of serum urviving found that preoperative serum urviving in rats with irreversible PAH-CHD was significantly higher than that in rats with reversible PAH-CHD and that there was also a significant correlation between serum urviving and BNP, preoperative PVR index, and postoperative mPAP (81). This evidence concerns the gene NPPB and pulmonary arterial hypertension.