Revisiting the Clinical Interpretation of CT-Measured Pulmonary Artery-to-Aorta Ratio—The Rotterdam Study

RationaleThe pulmonary artery (PA) diameter-to-aorta ratio (PA:A) ratio is a novel marker in cardiovascular imaging for detecting pulmonary hypertension. However, we question the effect of the varying aorta diameter on the ratio, which complicates the interpretation of the PA:A ratio.ObjectiveInvestigate the variability of the PA:A ratio by examining the correlation between PA:A ratio and aorta diameter and by comparing the associations of the PA diameter, aorta diameters, and PA:A ratio.MethodsWe included 2197 participants from the Rotterdam Study who underwent non-contrast multidetector computed tomography to measure the PA and aorta diameters. Pearson correlation coefficient was calculated between the PA:A ratio and aorta diameter. Multiple linear regression analyses were performed to compare the determinants of the individual diameters and PA:A ratio.ResultsWe found a statistically significant correlation between the PA:A ratio and aorta diameter (r = −0.38, p < 0.001). The PA diameter was statistically significantly associated with, height, weight, diastolic blood pressure, blood pressure medication, prevalence of atrial fibrillation, prevalence of heart failure, and prevalence of stroke (p < 0.05). Except for blood pressure medication, the PA:A ratio had similar determinants compared to the PA diameter but was also statistically significantly associated with sex, and systolic blood pressure (p < 0.05), which were statistically significantly associated with the aorta diameter (p < 0.05).ConclusionThe PA:A ratio should not be interpreted without taking into account the variability of the individual components (PA and aorta diameter) according to the anthropomorphic and clinical characteristics. The pulmonary artery (PA) diameter-to-aorta ratio (PA:A) ratio is a novel marker in cardiovascular imaging for detecting pulmonary hypertension. However, we question the effect of the varying aorta diameter on the ratio, which complicates the interpretation of the PA:A ratio. Investigate the variability of the PA:A ratio by examining the correlation between PA:A ratio and aorta diameter and by comparing the associations of the PA diameter, aorta diameters, and PA:A ratio. We included 2197 participants from the Rotterdam Study who underwent non-contrast multidetector computed tomography to measure the PA and aorta diameters. Pearson correlation coefficient was calculated between the PA:A ratio and aorta diameter. Multiple linear regression analyses were performed to compare the determinants of the individual diameters and PA:A ratio. We found a statistically significant correlation between the PA:A ratio and aorta diameter (r = −0.38, p < 0.001). The PA diameter was statistically significantly associated with, height, weight, diastolic blood pressure, blood pressure medication, prevalence of atrial fibrillation, prevalence of heart failure, and prevalence of stroke (p < 0.05). Except for blood pressure medication, the PA:A ratio had similar determinants compared to the PA diameter but was also statistically significantly associated with sex, and systolic blood pressure (p < 0.05), which were statistically significantly associated with the aorta diameter (p < 0.05). The PA:A ratio should not be interpreted without taking into account the variability of the individual components (PA and aorta diameter) according to the anthropomorphic and clinical characteristics.