Absence of Pulmonary Artery Growth After Fontan Operation and Its Possible Impact on Late Outcome

Background: The purpose of this study was to evaluate the development of the pulmonary arteries (PAs) after Fontan operation in children at long term. Methods: Thirty-five patients in whom Fontan operation was performed at median age of 4.2 years (range, 1.5 to 16.1 years) underwent angiographic measurements of the central and lower lobe PA diameter before Fontan operation and during the median follow-up of 4.6 years (range, 1.4 to 15.1 years). The median patient age at follow-up was 8.6 years (range, 3.4 to 27.2 years). Body surface area-dependent PA index and lower lobe index were calculated, and preoperative and follow-up values were compared. A correlation between the PA indices and the duration of the follow-up as well as between PA indices and the outcome was investigated. Results: Although percentile parallel somatic development of the children could be documented by body surface area measurements (0.62 to 0.93 m² during the follow-up; p < 0.001), the PA showed no gain in diameter at all. The PA index and lower lobe index (preoperative median, 261 and 138 mm²/m², respectively) decreased significantly during the follow-up period (median, 177 and 109 mm²/m²;p < 0.001). The lowest PA index was noted in patients who had the longest follow-up (R = 0.5; p = 0.009). We found a correlation between a low PA index and an unfavorable Fontan outcome (n = 10, p = 0.002). Conclusions: Growth of PAs after Fontan operation is clearly reduced despite somatic growth. This phenomenon may lead to an increase in pulmonary vascular resistance and could be a limit for optimal Fontan circulation in grown children in the long term.