Measurements of Pulmonary Artery Size for Assessment of Pulmonary Hypertension by Cardiovascular Magnetic Resonance and Clinical Application

Background and objective Pulmonary hypertension (PH) often leads to dilatation of main pulmonary artery (MPA). MPA measurements can be used to predict PH. This aim of this study is to investigate power of MPA vessel indices, which are acquired from cardiovascular magnetic resonance, to evaluate PH. Methods Cardiovascular-magnetic-resonance-determined parameters of MPA were acquired and calculated in 83 PH patients, whose diagnosis were confirmed with right heart catheterization and 49 healthy volunteers; these parameters included MPA diameter (DPA), ratio of DPA and ascending aorta diameter (DPA/DAo), max mean diameter (MDmax), min mean diameter (MDmin), fraction transverse diameter (fTD), fraction longitudinal diameter (fLD), and distensibility. Results Compared with control group, DPA, DPA/DAo, MDmax, and MDmin were significantly higher in patients with PH (P<0.001); fTD, fLD, and distensibility significantly decreased (P<0.001). fTD was lesser than fLD in control group (P<0.001), whereas difference was not observed in PH (P=0.305). MPA indices were significantly correlated with mean pulmonary arterial pressure (mPAP) (P<0.05), and strongest correlation was observed for DPA/DAo (r=0.534, P<0.001). By receiver operating characteristic analysis, MDmin>28.4 mm, and MDmax>32.4 mm (area under the curve, AUC=0.979, 0.981) showed best performance in predicting PH, yielding highest specificity at 100%. Conclusion Noninvasive cardiovascular-magnetic-resonance-derived MPA measurements provide excellent and practical reference in clinical settings for detecting PH.