PURPOSE: Aim of this study was to determine whether the diameter ratio of main pulmonary artery /aortic diameter (dPA/dAO) as assessed on computed tomography scan of the chest (Chest CT) is predictive of pulmonary artery hypertension (PAH).
METHODS: 29 patients (mean age 62±13) with documented pulmonary artery hypertension (mean pulmonary artery pressure >=25 mm Hg, pulmonary artery wedge pressure < 18) confirmed by right heart catheterization and had a Chest CT were studied. Controls (n=12 mean age 60±8) were defined as patients who were referred for suspected PAH with dyspnea on exertion, but were not confirmed to have PAH by right heart catheterization [mean PAP < 25mmHg and PCWP < 18mmHg]. The measure of dPA/dAO was performed by a pulmonary fellow and attending radiologist on a single defined CT section. Statistical analysis was done using the software Mathcad (parametric technology corporation).
RESULTS: The mean dPA/dAO in patients with confirmed PAH was 1.1(±0.22). The mean dPA in controls was 0.81(±0.11). The mean dPA/dAO was significantly greater in patients with confirmed PAH [two tailed tests: P<0.001]. Using receiver operator curve characteristics, a cut off value of 0.9 was determined as the best discriminator. With this cutoff, sensitivity of dPA/dAO to predict a presence of PAH was 0.897, specificity was 0.727, negative predictive value was 0.727, and positive predictive value was .897. dPA/dAO did not correlate linearly with hemodynamic variables in patients with confirmed PAH.
CONCLUSION: Using a dPA /dAO >0.9 on Chest CT may help predict the presence of PAH non-invasively.
CLINICAL IMPLICATIONS: The current standard to diagnose patients with PAH is with an invasive procedure (right heart catherization). Although pulmonary artery diameter alone has been evaluated as a non-invasive method to predict PAH, using pulmonary artery diameter alone has a poor sensitivity with a good specificity. Our study demonstrates a good sensitivity and specificity by using a ratio to predict PAH. Clinicians should consider Pulmonary Artery diameter in conjunction with the dPA/dAO to help predict PAH while reviewing CT scans.
DISCLOSURE: Hans Lee, No Financial Disclosure Information; No Product/Research Disclosure Information