What is the condition called when the bicuspid valve doesn't close?

Aortic Insufficiency. I assume the bicuspid valve here is the aortic valve. A bicuspid aortic valve usually does not close properly and therefore leaks the blood backwards to the left ventricle. This is usually not a major issue until the fifth or sixth decade of life when the valve will likely need to be replaced. A person with bicuspid aortic valve should have regular follow up with a cardiologist.