3D CT and angiography show variable accuracy for PDA stent sizing depending on ductal tortuosity

BackgroundPatent Ductus Arteriosus (PDA) stenting has become an established albeit complex intervention in ductal dependent congenital heart disease. Accurate pre-procedural planning is essential for successful stent placement, yet the optimal measurement methodology remains debated. This study compared the accuracy and clinical utility of routine pre-procedural three-dimensional (3D) computed tomography-derived measurements with traditional angiographic assessments for PDA stent sizing.MethodsWe analyzed 21 consecutive PDA stenting cases from Sheba Medical Center (01/2021–10/2023) with a median age of 14 days (IQR: 8–19) and mean weight of 3.6 ± 2.2 kg. Patients were stratified by anatomical complexity: Group 1 (0 turns, n = 6), Group 2 (1 turn, n = 3), and Group 3 (≥2 turns, n = 12). PDA length measurements from CTA-derived 3D reconstruction and 2D angiography were compared against the actual stent length used. Statistical analysis included Pearson correlation, Bland–Altman agreement, and concordance correlation coefficients (CCC).ResultsIn the overall cohort, both 3D (r = 0.692) and angiographic (r = 0.811) measurements correlated with stent length. Performance varied significantly by anatomical complexity. In Group 1 (straight), angiography demonstrated favorable accuracy with lower bias (−0.28 mm vs. 1.33 mm) and higher concordance (CCC: 0.807 vs. 0.681). In Group 2 (moderate tortuosity), angiographic performance showed greater underestimation and lower concordance (Bias −5.67 mm; CCC: 0.168), while 3D remained reliable (Bias −2.33 mm; CCC: 0.526). In Group 3 (severe tortuosity), 3D overestimated length (+3.1 mm) while angiography underestimated it (−2.88 mm), though angiographic consistency was higher (CCC: 0.704 vs. 0.559).ConclusionPre-procedural 3D measurements provide consistent reliability across varying degrees of anatomical complexity, offering an advantage in cases with moderate tortuosity where angiography may be vulnerable to foreshortening. Angiography remains highly accurate for straightforward anatomy. A complexity-stratified imaging approach is recommended to optimize stent selection.