Sirolimus improves survival in paediatric pulmonary vein stenosis

Use of systemic sirolimus therapy (SST) provides a survival benefit in infants and children with moderate-to-severe pulmonary vein stenosis (PVS) that persists even after adjusting the analysis for survival bias, a study has found.

In addition, two mild adverse events (AEs) associated with SST had been recorded during the study period, but both patients have been able to continue treatment without recurrence.

The authors of this single-centre study considered patients with severe PVS for SST following a strict protocol while receiving standardized surveillance and anatomic therapies. They compared the SST cohort with a contemporary control group to determine whether mTOR inhibition with sirolimus as primary medical therapy would improve outcomes in high-risk patients.

The PVS programme diagnosed and treated 67 patients with moderate-to-severe PVS between 2015 and 2020, of whom 15 were treated with sirolimus, and the rest represented the control group.

Patients in the SST group had 100-percent survival as opposed to only 45 percent in the control group (log-rank p=0.004). A sensitivity analysis completed to address survival bias using the median time from diagnosis of PVS to SST showed that the survival advantage persisted with SST (log-rank p=0.027). Of note, two patients developed sirolimus-related AEs, but both were treated and had no recurrence.

Patients in the SST group underwent frequent transcatheter intervention (3.7 catheterizations per person-year; 25th to 75th percentile: 2.7–4.4 person-years). Median follow-up time was 2.2 years (25th to 75th percentile: 1.2–2.9 years) in the SST arm vs 0.9 years (25th to 75th percentile: 0.5–2.7 years) in the control arm.