Due to Health Canada losartan recall, a new formulation being added to the protocol/ temporary suspension

This pilot study evaluates the safety and feasibility of losartan in pediatric patients with pulmonary vein stenosis.

It is an open label single arm interventional study. The patient population involves pediatric patients with stenosis in 2 or more pulmonary veins. Patients will be given losartan for 1 year. Outcomes include measures of safety/adverse events and progression of pulmonary vein stenosis.

This pilot study evaluates the safety and feasibility of losartan in pediatric patients with pulmonary vein stenosis.

Large animal studies have demonstrated that losartan can ameliorate the progression of pulmonary vein stenosis in a surgical model of pulmonary vein stenosis.

There is no safety data for losartan in children < 6months of age or in children with pulmonary vein stenosis. Therefore, this study will test the safety and feasibility of losartan in children in an open label single arm interventional study.

Patient inclusion criteria includes stenosis involving 2 or more pulmonary veins. Patients who are consented into the trial with be on losartan therapy for one year. They will undergo study visits every 3 months. Patients will be screened for adverse events through biochemical tests, routine clinical tests and questionnaires.

An exploratory efficacy analysis will compare progression of pulmonary vein stenosis in children enrolled in losartan to a contemporary cohort of children with pulmonary vein stenosis, who did not receive losartan.

Inclusion Criteria:

• Stenosis involving 2 or more pulmonary veins
• Consent of parent/legal guardian or child(when appropriate)

Exclusion Criteria:

• History of angioedema or allergic reaction to angiotensin converting enzyme inhibitors
• corrected gestational age of less than 40 weeks
• severe renal dysfunction
• pregnancy