Pulmonary Artery Dilatation Due to Pressure or Volume Overload in Congenital Heart Disease

Background: Pulmonary artery dilatation is described mostly in association with pulmonary hypertension. Patients/Methods: Study analysis: 60 patients with pulmonary arterial hypertension in congenital heart disease (PAH-CHD); 64 with repaired tetralogy of Fallot/pulmonary regurgitation (rTOF/PR); and 80 healthy (NORMAL). Measured were: main pulmonary artery (MPA) diameter and MPA/ascending aorta (Ao asc) ratio, by echocardiography (ECHO) and computer tomography or magnetic resonance imaging (CT/MRI). Results: In MPA diameter, significant differences between PAH-CHD, rTOF/PR, and NORMAL were found (median): 37 vs. 27 vs. 21 mm (p < 0.0001). In MPA/Ao asc ratio, there was a difference between PAH-CHD and NORMAL (median): 1.3 vs. 0.8 (p < 0.0001), but not between rTOF/PR and NORMAL: 0.74 vs. 0.8 (p = 0.3). Significant MPA dilatation (>40 mm) was present: in PAH-CHD, 35% (ECHO) and 76.9% (CT/MRI) of patients, while in rTOF/PR, 3.1% (ECHO) and 7.8% (CT/MRI). Severe MPA dilatation (>50 mm) occurred only in PAH-CHD: 16.7% (ECHO) and 31.4% (CT/MRI), while not in rTOF/PR. There was a significant correlation between ECHO and CT/MRI measurements, but ECHO was underestimated in all parameters. Conclusions: MPA dilatation due to pressure overload is more frequent and more severe; volume overload also leads to MPA dilatation but is less severe. The MPA/Ao asc ratio is not reliable for MPA dilatation estimation in rTOF/PR.