What is the significance of a sticky heart valve?

Depends on degree: This depends on the degree of tightness (stenosis). In the US, the aortic valve is the most common valve affected by this condition. If the valve is considered severely stenosed, then over time it will lead to congestive heart failure and it has to be replaced.

Valve: The valve opens to allow flow out of the heart to the body. If it doesn't open properly we call this stenosis. It has to close properly to keep blood flowing in a forward direction. If it doesn't we call this insufficiency. Either or both abnormalities can exist in the valve. Severe stenosis results in decreased cardiac output eventually as does severe insufficiency.