This is a problem when a hole or defect develops in the area where an artificial heart valve is sewn into the heart. The valve replacement is performed for damage to the native (normal valve). If the tissues that the stitches are placed into is weak or infected, they may not be strong enough to support the artificial valve and then a hole may appear. This allows blood to leak back around the valve and can cause heart failure and problems with blood (haemolysis).

Collaboratively Dr. Shapiro and his colleagues have developed techniques for placing plugs into these leaks via a vein. This often completely seals the defect and prevents the need for a further operation.