Clinical and Predictive Value of Computed Tomography Angiography in High-Altitude Pulmonary Hypertension.

Background: High-altitude pulmonary hypertension (HAPH), as the group 3 pulmonary hypertension, has been less studied so far. The limited medical conditions in the high-altitude plateau are responsible for the delay of the clinical management of HAPH.

Objectives: This study aims to identify the imaging characteristics of HAPH and explore noninvasive assessment of mean pulmonary arterial pressure (mPAP) based on computed tomography angiography (CTA).

Methods: Twenty-five patients with suspected HAPH were enrolled. Right heart catheterization (RHC) and pulmonary angiography were performed. Echocardiography and CTA image data were collected for analysis. A multivariable linear regression model was fit to estimate mPAP (mPAP). A Bland-Altman plot and pathological analysis were performed to assess the diagnostic accuracy of this model.

Results: Patients with HAPH showed slow blood flow and coral signs in lower lobe pulmonary artery in pulmonary arteriography, and presented trend for dilated pulmonary vessels, enlarged right atrium, and compressed left atrium in CTA ( for trend <0.05). The left lower pulmonary artery-bronchus ratio (odds ratio: 1.13) and the ratio of right to left atrial diameter (odds ratio: 1.09) were significantly associated with HAPH, and showed strong correlation with mPAP, respectively (r = 0.821 and r = 0.649, respectively; all  < 0.0001). The mPAP model using left lower artery-bronchus ratio and ratio of right to left atrial diameter as covariates showed high correlation with mPAP (r = 0.907;  < 0.0001). Patients with predicted HAPH also had the typical pathological changes of pulmonary hypertension.

Conclusions: Noninvasive mPAP estimation model based on CTA image data can accurately fit mPAP and is beneficial for the early diagnosis of HAPH.