Novel computed tomographic chest metrics to detect pulmonary hypertension

Abstract

Background: Early diagnosis of pulmonary hypertension (PH) can potentially improve survival and quality of life. Detecting PH using echocardiography is often insensitive in subjects with lung fibrosis or hyperinflation. Right heart catheterization (RHC) for the diagnosis of PH adds risk and expense due to its invasive nature. Pre-defined measurements utilizing computed tomography (CT) of the chest may be an alternative non-invasive method of detecting PH.

Methods: This study retrospectively reviewed 101 acutely hospitalized inpatients with heterogeneous diagnoses, who consecutively underwent CT chest and RHC during the same admission. Two separate teams, each consisting of a radiologist and pulmonologist, blinded to clinical and RHC data, individually reviewed the chest CT's.

Results: Multiple regression analyses controlling for age, sex, ascending aortic diameter, body surface area, thoracic diameter and pulmonary wedge pressure showed that a main pulmonary artery (PA) diameter ≥29 mm (odds ratio (OR)=4.8), right descending PA diameter ≥19 mm (OR=7.0), true right descending PA diameter ≥16 mm (OR=4.1), true left descending PA diameter ≥21 mm (OR=15.5), right ventricular (RV) free wall ≥6 mm (OR=30.5), RV wall/left ventricular (LV) wall ratio ≥0.32 (OR=8.8), RV/LV lumen ratio ≥1.28 (OR=28.8), main PA/ascending aorta ratio ≥0.84 (OR=6.0) and main PA/descending aorta ratio ≥1.29 (OR=5.7) were significant predictors of PH in this population of hospitalized patients.

Conclusion: This combination of easily measured CT-based metrics may, upon confirmatory studies, aid in the non-invasive detection of PH and hence in the determination of RHC candidacy in acutely hospitalized patients.

Figure 1

Radiographic measurements. The radiometric measurements used to derive the predictors of PH that were found to be significant in Table 6 included: main PA (a), AA (b), DA (c), RV free wall (d), RV lumen (e), LV lumen (f), LV free wall (g), true RDPA (h), RDPA as would be seen on chest x-ray (i), and true LDPA (j).