Transcatheter Recanalization of Atretic Pulmonary Veins in Infants and Children.

BACKGROUND: Pulmonary vein stenosis is a progressive disease associated with a high rate of mortality in children. If left untreated, myofibroblastic proliferation can lead to pulmonary vein atresia (PVA). In our experience, transcatheter recanalization has emerged as a favorable interventional option. We sought to determine the acute success rate of recanalization of atretic pulmonary veins and mid-term outcomes of individual veins after recanalization. METHODS: We reviewed all patients with PVA at our institution between 2008 and 2020 diagnosed by either catheterization or cardiac computed tomography. All veins with successful recanalization were reviewed and procedural success rate and patency rate were noted. Competing risk analysis was performed to demonstrate outcomes of individual atretic veins longitudinally. RESULTS: Between 2008 and 2020, our institution diagnosed and treated 131 patients with pulmonary vein stenosis. Of these, 61 patients developed atresia of at least one pulmonary vein. In total, there were 97 atretic pulmonary veins within this group. Successful recanalization was accomplished in 47/97 (48.5%) atretic veins. No atretic pulmonary veins were successfully recanalized before 2012. The majority of veins were recanalized between 2017 and 2020-39/56 (70%). The most common intervention after recanalization was drug-eluting stent placement. At 2-year follow-up 42.6% of recanalized veins (20.6% of all atretic veins) remained patent with a median of 4 reinterventions per person. CONCLUSIONS: Transcatheter recanalization of PVA can result in successful reestablishment of flow to affected pulmonary veins in many cases. Drug-eluting stent implantation was the most common intervention performed immediately post-recanalization. Vein patency was maintained in 42.6% of patients at 2-year follow-up from recanalization with appropriate surveillance and reintervention. Overall, only a small portion of atretic pulmonary veins underwent successful recanalization with maintained vessel patency at follow-up. Irrespective of successful recanalization, there was no detectable survival difference between the more recently treated PVA cohort and non-PVA cohort.

Systemic Sirolimus Therapy for Infants and Children With Pulmonary Vein Stenosis.

BACKGROUND: Anatomic interventions for pulmonary vein stenosis (PVS) in infants and children have been met with limited success. Sirolimus, a mammalian target of rapamycin inhibitor, has demonstrated promise as a primary medical therapy for PVS, but the impact on patient survival is unknown. OBJECTIVES: The authors sought to investigate whether mTOR inhibition with sirolimus as a primary medical therapy would improve outcomes in high-risk infants and children with PVS. METHODS: In this single-center study, patients with severe PVS were considered for systemic sirolimus therapy (SST) following a strict protocol while receiving standardized surveillance and anatomic therapies. The SST cohort was compared with a contemporary control group. The primary endpoint for this study was survival. The primary safety endpoint was adverse events (AEs) related to SST. RESULTS: Between 2015 and 2020, our PVS program diagnosed and treated 67 patients with ≥moderate PVS. Of these, 15 patients were treated with sirolimus, whereas the remaining patients represent the control group. There was 100% survival in the SST group compared with 45% survival in the control group (log-rank p = 0.004). A sensitivity analysis was completed to address survival bias using median time from diagnosis of PVS to SST. A survival advantage persisted (log-rank p = 0.027). Two patients on sirolimus developed treatable AEs. Patients in the SST group underwent frequent transcatheter interventions with 3.7 catheterizations per person-year (25th to 75th percentile: 2.7 to 4.4 person-years). Median follow up time was 2.2 years (25th to 75th percentile: 1.2 to 2.9 years) in the SST group versus 0.9 years (25th to 75th percentile: 0.5 to 2.7 years) in the control group. CONCLUSIONS: The authors found a survival benefit associated with SST in infants and children with moderate-to-severe PVS. This survival benefit persisted after adjusting the analysis for survival bias. There were 2 mild AEs associated with SST during the study period; both patients were able to resume therapy without recurrence.