Can pulmonary artery morphology influence the differential pulmonary flow?

Abstract Background and purpose Variations of pulmonary arteries’ diameter and morphology are commonly encountered in different congenital heart diseases (CHD). They can have a profound impact on differential pulmonary flow (DPF). Abnormal DPF means unbalanced flow between both lungs, which can occur with various CHDs. This study aims to answer whether a significant difference in the differential pulmonary flow (SDDPF) is correlated with the complex morphometrics of the pulmonary arteries as an independent risk factor from the caliber. Patients and methods A retrospective study involved 152 patients who underwent cardiac magnetic resonance (CMR), including phase-contrast MRI (PC-MRI) of the main, right, and left pulmonary arteries (PAs). Evaluation of the caliber and morphology of the PAs, as well as the presence or absence of SDDPF through PC-MR, was done. Correlation between the discrepancy in pulmonary branch diameter (DPBD), major diagnosis, right ventricle (RV) size, function, pulmonary regurgitation (PR), and pulmonary artery morphology (PAM) versus SDDPF was evaluated. Results Forty patients had one or more morphologic patterns of concern. The most prevalent pattern among the patients with peculiar pulmonary artery morphology was left pulmonary artery (LPA) kink (57.5%). The SDDPF was observed more frequently in the group with peculiar PAM compared to the other group without this peculiar morphology ( P -value = 0.000003). Conclusions The morphology of the pulmonary arteries (PAs) is a critical determinant of differential pulmonary blood flow, independent of their diameters. Among the various morphological patterns observed, the kink in the LPA is particularly prevalent and plays a consequential role in the discrepancies noted in pulmonary perfusion.