Exploring the Relationship Between Pulmonary Artery Shape and Pressure in Pulmonary Hypertension: A Statistical Shape Analysis Study

Pulmonary Hypertension (PH) is a progressive condition affecting the right heart, defined by a mean pulmonary arterial pressure (mPAP) greater than 20 mmHg. Measuring mPAP with a pressure catheter is the gold standard for diagnosing PH despite its associated costs and risks. As an alternative, this work investigates the inference of mPAP from pulmonary vasculature anatomy. We thus studied the shape of the main pulmonary artery trunk along with its left and right branches (MPA, LPA, and RPA) across a population of group I PH patients and investigated the relationship between shape and mPAP. Computed Tomography images from 80 confirmed PH cases were used to create a statistical shape model: anatomy was manually segmented, represented by 3 centerlines and radii at evenly spaced control points, and reduced in dimensionality by Principal Component Analysis (PCA). The correlation between each PCA mode of variation and mPAP was then used to identify relevant shape features associated with elevated pressure, which were finally combined in a linear regression model. Results reveal that changes in MPA’s diameter and bulging, as well as in the angle between RPA and LPA, related to mPAP. A linear combination of the first 12 modes, with a cumulative variance of 95%, resulted in a linear regression model explaining 36% of mPAP variability in the population, while a combination of the 6 most relevant PCA modes was able to explain 34% of mPAP variability. These results provide initial evidence of the ability to infer mPAP from pulmonary arteries anatomy in PH patients.