A high cholesterol level can mean your body already had high levels of inflammation, so it produces more cholesterol to "fix it". But a side-effect of that is that it clogs your arteries. And it's worse when you have a Vitamin K2-deficient diet, which means calcium is slowly accumulated into your tissues and arteries.
Heart attack is caused by the "plaque" that "breaks off". So I'm thinking it wouldn't be a plaque with just the cholesterol alone. It needs the calcium to really turn dangerous.
I think everyone needs to do a CAC test. But it seems most doctors believe only the US president and astronauts are good enough for it.
This documentary on it is a good one: