I like your idea, and also find it very frustrating that we all continue to suffer in this day and age, when technology is supposedly at its optimum, why has such a valve (or similar product) not been created?
I thought Endostim was a step towards this, perhaps I am misinformed. Perhaps you could get your engineers hat on and see what you could come up with, as no one else in the medical community seems remotely interested.
Perhaps if we all pitch in ideas, something could finally be created. As they say, a great answer always starts with a good question.