Cardiovascular parameters of computed tomographic pulmonary angiography to assess pulmonary vascular resistance in patients with chronic thromboembolic pulmonary hypertension

Abstract

Objectives: The purpose is to identify the role of cardiovascular parameters of computed tomographic pulmonary angiography (CTPA) to assess pulmonary vascular resistance (PVR) in patients with chronic thromboembolic pulmonary hypertension (CTEPH).

Background: The assessment of PVR is of great importance in the management of patients with CTEPH. The role of CPTA in assessment of PVR of CTEPH remains to be explored.

Methods: Clinical and radiological data of 90 patients (55 men, age 17-84 years) with CTEPH were retrospectively reviewed in this study. All patients received CTPA before right-heart catheterization. Cardiovascular parameters and Pulmonary Artery Obstruction Indices including Qanadli Index and Mastora Index were evaluated on CTPA. Hemodynamic PVR was calculated with the standard formula according to data from right-heart catheterization. The correlation of cardiovascular parameters of CTPA and PVR was analyzed.

Results: In Cardiovascular parameters, neither Qanadli Index(r=0.134, p=0.208) nor Mastora Index (r=0.149, p=0.90) did correlate with PVR. Cobb angle(r=0.613, p=0.000), the ratio of right to left ventricular area(r=0.422, p=0.000)and the ratio of right to left ventricular transverse diameter (r=0.410, p=0.000) respectively correlated with PVR. By receiver operating characteristic curve analysis, a Cobb angle cutoff value of 67.55° had a sensitivity of 72.5% and a specificity of 84.0% to determine PVR ≥1000 (dyn.sec/cm(5)) and its Area Under Curve is (0.800 ± 0.048). By stepwise linear regression analysis, Cobb angle was only one variable (R=0.601) shown to be independently associated with PVR, leading to the following equation: PVR=25.796 × Cobb angle-585.935(F=37.929, p=0.000).

Conclusion: The analysis of CTPA-derived cardiovascular parameters, especially the Cobb angle, is a reliable tool for estimating PVR in patients with CTEPH, but Pulmonary Artery Obstruction Indices do not correlate with PVR.