The SIR-POBA Shunt Trial

Inclusion Criteria: * Age at least 18 years * Informed consent with signature * Maturated shunt, defined as already in use for two weeks * Shunt stenosis in need of intervention Exclusion Criteria * Pregnant or breastfeeding women * Active infection or sepsis * Incapacitated patients * Lesions in the affected stenosis already pretreated by stenting in the same area shunt. * Patients currently participating in another study * Central venous stenosis worthy of treatment * intolerance to sirolimus * coagulopathy * radiotherapy * patients on immunosuppressive therapy * use of potent CYP3A4 and/or P-gp inhibitors (such as ketoconazole, Voriconazole, itraconazole, erythromycin, telithromycin, or clarithromycin) or strong CYP3A4 and/or P-gp inducers (such as rifampin or rifabutin).