Management of Pediatric Pulmonary Vein Stenosis

Real-Time Assessment of Pulmonary Blood Flow in Pulmonary Vein Stenosis Using the Fluoroscopic Flow Calculator

Background

Restenosis in pediatric pulmonary vein stenosis (PVS) is common and requires careful monitoring. Lung perfusion scintigraphy (LPS) is often used but involves excess radiation, is resource-intensive, and can cause patient discomfort, with no real-time data available. This study evaluated the fluoroscopic flow calculator (FFC) as a real-time tool for estimating pulmonary blood flow (Qp) using angiograms during catheterization, with the potential to replace or complement LPS.

Methods

A retrospective cross-sectional study was conducted on patients with PVS who underwent cardiac catheterization between April 1, 2023, and March 31, 2024 at the Children's Hospital of Philadelphia. The study included patients who had a right ventricular angiogram and available LPS data. The FFC tool was used to analyze angiograms and estimate Qp distribution. Accuracy was assessed by comparing FFC predictions to LPS measurements using median absolute error and Bland-Altman analysis.

Results

The study included 21 procedures involving 18 patients, with a median age of 17 months. The FFC tool provided accurate predictions of Qp distribution, with a median absolute error of 3%. In 76% of cases, the predicted flow split was within 5% of the LPS measurement, and all cases were within 7%. Bland-Altman analysis revealed a minimal bias of +0.3%, with no systematic bias at the extremes of the flow-split distribution.

Conclusions

The FFC tool shows promise in estimating Qp distribution during cardiac catheterization in PVS patients. Further research is needed to refine the FFC method, particularly incorporating segmental lung information, and to evaluate its real-time use during catheterization.

Incidence and Risk Factors of Pulmonary Vein Stenosis After Orthotopic Heart Transplantation in Pediatric Patients

Pulmonary vein stenosis (PVS) is a rare yet critical condition in children with a poor prognosis. The incidence and underlying risk factors of PVS following orthotopic heart transplantation (OHT) remain unclear. This study aimed to investigate the occurrence and predictors of PVS development post-OHT among pediatric recipients. This retrospective, single-center study was conducted at Cincinnati Children's Hospital Medical Center included patients who underwent OHT between 2014 and 2023. Demographics were compared between patients who developed PVS after OHT and those who did not. Cox regression analyses was used to identify predictors of PVS development. Among 114 patients (70 males, 61%) who underwent OHT at a median age of 11 years (IQR: 2-15), 12 were diagnosed with PVS (6 males, 50%) during a median follow-up of 29 months (IQR: 14-63). The median interval between OHT and diagnosis of PVS was 2 months (IQR: 1-8). All 12 PVS cases were associated with underlying congenital heart disease (12/69, 17.4%) including 2 patients with history of PVS at time of transplant. No patients with history of cardiomyopathy or myocarditis developed PVS. Among the 12 PVS patients, 3 (25%) had multivessel pulmonary vein disease and 4 patients (33%) died. Cox regression analysis, after excluding 2 patients with a prior history of PVS, identified age at OHT (Hazard ratio 0.86, p = 0.027) and partial or total anomalous pulmonary venous return (Hazard ratio 9.0, p = 0.002) as significant predictors of PVS development post-OHT. Prematurity, chronic lung disease, single ventricle physiology and donor-recipient size mismatch were not significantly associated with development of PVS post-OHT. The patients with PVS had significantly higher mortality compared to those without PVS (p = 0.025). This study highlights a low risk of PVS post-OHT in children with cardiomyopathy or myocarditis. PVS post-transplant is linked to congenital heart disease and early post-transplant period. Monitoring for PVS during the first year post-OHT is crucial, especially in children with congenital heart disease.

Mortality Patterns in Pediatric Pulmonary Vein Stenosis: Insights Into Right Ventricular Systolic Pressure Associations

BACKGROUND

Pulmonary vein stenosis in children is associated with a poor prognosis. However, the cause and risk factors for mortality remain uncertain.

METHODS

This retrospective, single-center study identified children with primary and secondary pulmonary vein stenosis through a cardiac catheterization database. Kaplan-Meier analysis, log-rank tests, and Cox regression analysis were performed to assess outcome and identify significant predictors of mortality.

RESULTS

Among 56 children with pulmonary vein stenosis (33 male children, 59%), 20 (36%) died at a median age of 10 months (interquartile range, 4-24 months). All patients underwent cardiac catheterization, with 45 (80%) undergoing at least 1 interventional procedure. Causes of death included multiorgan failure (35%), progressive respiratory failure (20%), and sudden cardiac death (15%). Prematurity, chronic lung disease, a genetic syndrome, or the number of affected pulmonary veins did not significantly correlate with mortality. However, right ventricular (RV) systolic pressure greater than half systemic pressure was associated with mortality (hazard ratio [HR], 5.5 [95% CI, 2.2-14.1]; P<0.001). The final predictive model for mortality included RV systolic pressure greater than half systemic pressure (HR, 4.0 [95% CI, 1.6-10.4]; P=0.004), moderately or severely diminished RV systolic function (HR, 3.6 [95% CI, 1.1-11.5]; P=0.032), and the presence of congenital heart disease (HR, 2.4 [95% CI, 0.9-6.7]; P=0.084).

CONCLUSIONS

This report is the first to indicate that RV systolic pressure and RV dysfunction are significant independent predictors of mortality in children with pulmonary vein stenosis. A greater understanding of mortality in this population is necessary, particularly in those with RV systolic pressure less than half systemic.

In vitro performance of Lifetech IBS Angel™ (iron-based bioresorbable scaffold) stents during overdilation for use in pediatric patients

Objectives

The objective of this study was to assess the mechanical performance of the Lifetech IBS Angel stents during overdilation as is often required in pediatric applications; including time of first fracture, foreshortening, and the type of fracturing that occurs.

Materials and methods

In vitro testing was performed and repeated for each stent three times under physiologic conditions with continuous audiovisual imaging allowing for post-testing evaluations. Assessment of sheath fit was also completed.

Results

A total of 47 stents on monorail system were overdilated to complete fracture after passing through either a 4 or 5 French sheath. First strut fracture occurred in 4 and 6 mm stents when they reached greater than 50% overexpansion. Larger stents could achieve at least 30% increased diameter prior to first strut fracture. No fragmentation of any of the stents was seen throughout testing.

Conclusion

The IBS Angel has thin struts allowing for a lower profile with increased maneuverability and use with smaller sheaths. Embolization potential of strut fragments was not seen. Increased diameter well beyond design parameters was seen in all with acceptable foreshortening.