Stent placement in pulmonary artery
A pulmonary artery stent is used following balloon dilatation of a narrowed (stenosed) pulmonary artery.

The stent is a metal scaffold which helps to keep the dilated artery open.
The diagram shows the stent mounted on a catheter, before, during and after balloon inflation.

How to interpret the survival funnel plots

These graphs show the national average survival after specific procedures for treating congenital heart disease. The national average is shown as a horizontal grey line. Two control limits are shown; a warning limit (Green line, 98%) and an alert limit ( Red line 99.5%). Unit performances are shown as identifiable coloured symbols. If a unit's symbol is above the green line then the performance is no different from the national average. If a unit’s survival rate is below the warning limit, their performance will be closely monitored in subsequent years. If a unit’s survival rate is below the alert limit, an investigation into possible reasons and remedial actions will be launched by the appropriate professional and regulatory bodies.