Morphologic characterization of the patent ductus arteriosus in the premature infant and the choice of transcatheter occlusion device

Objectives: The aim of this study was to describe and differentiate the morphology of patent ductus arteriosus (PDA) seen in children born prematurely from other PDA types. Background: PDAs are currently classified as types A-E using the Krichenko's classification. Children born prematurely with a PDA morphology that did not fit this classification were described as Type F PDA. Methods: A review of 100 consecutive children who underwent transcatheter device closure of PDA was performed. The diameter and length (L) of the PDA and the device diameter (D) were indexed to the descending aorta (DA) diameter. Results: Comparison of 26 Type F PDAs was performed against, 29 Type A, 7 Type C and 32 Type E PDAs. Children with Type F PDAs (median 27.5 weeks gestation) were younger during the device occlusion compared with types A, C, and E (median age: 6 vs. 32, 11, and 42 months; P = 0.002). Type F PDAs were longer and larger, requiring a relatively large device for occlusion than types A, C, and E (Mean L/DA: 1.88 vs. 0.9, 1.21, and 0.89, P ≤ 0.01 and Mean D/DA: 1.04 vs. 0.46, 0.87, and 0.34, P ≤0.01). The Amplatzer vascular plug-II (AVP-II) was preferred for occlusion of Type F PDAs (85%; P <0.001). Conclusions: Children born prematurely have relatively larger and longer PDAs. These "fetal type PDAs" are best classified separately. We propose to classify them as Type F PDAs to add to types A-E currently in use. The AVP-II was effective in occluding Type F PDAs.