Long-term follow-up results of lung perfusion studies after transcatheter closure of patent ductus arteriosus.

Objective: This study presents the long-term follow-up of patients who developed left lung perfusion (LLP) abnormalities following patent ductus arteriosus (PDA) closure with various device types.

Design: The study includes 23 adult and pediatric patients who had undergone transcatheter PDA closure and were shown to have decreased LLP (<40%) by the first scintigraphy performed within the average follow-up period of 14.0 ± 8.12 months (2.0-30 months). For PDA closure, the Amplatzer duct occluder was used in 12 patients, and coils were used in 11. Within the average period of 58.91 ± 12.93 months (37-85 months) after transcatheter PDA closure, a second lung perfusion scintigraphy was performed.

Results: In 13 out of 23 patients (56.5%), LLP improved by the time of the second scintigraphy. Improved and unimproved patients did not differ with regard to age, weight, body surface area, PDA diameter, ampulla diameter, and PDA length at the time of PDA closure and the second scintigraphy. There was no significant difference with regard to the percent of improved patients between the different device types (P =.88). The left pulmonary artery indexes were also insignificantly different (P =.446). Patients with persistent LLP abnormality had significantly higher average Doppler velocity index [(LPA blood flow velocity--RPA blood flow velocity) / MPA blood flow velocity] × 100 (P =.007) and PDA diameter/length. If Doppler velocity index ≥50% is taken as the cutoff value, it is possible to predict persisting LLP abnormality with 80% sensitivity and 76% specificity. Left lung perfusion abnormality was found to persist in patients with PDA diameter/length ≥0.5 with 80% sensitivity and 92.3% specificity.

Conclusions: The LLP abnormalities seen after PDA closure with various devices eventually improve to normal in the majority of patients during long-term follow-up. Patients whose PDA length is shorter than its diameter are at risk of developing LLP abnormalities that persist long-term.