Morphological evaluation for a narrowest section of the Patent Ductus Arteriosus in infants by Computed tomography: A crucial point for device closure

Objectives: We examined the diameter of cross section of the PDA minimum portion using contrast-enhanced CT findings to know the accurate morphology and size of them. Background Ordinarily, the device size is determined based on the minimal diameter of the PDA measured in the lateral view of angiography. Occasionally, the device may come out from the PDA easily even if the device size seems optimal. Methods From 2016 to 2021, 29 patients who underwent contrast-enhanced computed tomography (CT) prior to PDA closure included. Morphological evaluation of the narrowest part of the PDA was performed on contrast-enhanced CT. We also examined whether there were differences in morphology depended on Krichenko classification, age, and the diameter of the narrowest portion of the PDA. Results At the time of treatment, the median age was 4.8 (range, 1–52) months, the median weight was 5.0 (2.5–12.7) kg. The median minimum vertical diameter of PDA was 2.9 (1.6–6.6) mm. The narrowest PDA part in the contrast CT imaging showed horizontal-to-vertical diameter ratios in the range of 1.0–1.7, with no case where the vertical diameter was larger than the horizontal diameter. The median horizontal-to-vertical diameter ratio by Krichenko type was: type A, 1.22; type C, 1.29; type E, 1.62( p  = 0.017). When classifying the patients into a group aged under six months ( n  = 21) and a group aged six months or older ( n  = 8), the respective median horizontal-to-vertical diameter ratio was 1.34 and 1.15 ( p  = 0.027). The vertical PDA diameter was not correlated with the elliptical shape. Conclusions Most PDA cases have a horizontally-oriented elliptical shape. This characteristic showed high reproducibility and is important information that angiography cannot evaluate.