Deficiency of Vitamin K can lead to build up in arteries, but then why can't you give Vit K for blood clots?

What you have read is bunk!  Vitamin K has NOTHING to do with plaque buildup within arteries!  Vitamink K can reverse the effects of a blood thinner called Coumadin, so if someone is bleeding from having too high a level of Coumadin, then Vit K is part of the treatment for that.

Vitamin K helps to prevent hemmorage, that is it helps to clot the blood. I am not sure where you got that information from, but Vitamin K clots blood...if you had a vitmain K deficiency you would be at a risk for hemmorage.

Vitamin K deficience does indeed to play a part in CHD, but not in prevention of athersclreosis.
It is now becoming apparent that Vitamin K plays an impotrant role in determining where calcium is deposited. Those with a vitamin K deficience tend to have calcium deposited whithin athersclelopic plaque, thus hardening the arteries as well as higher risk of hip fractures. this hardening narrows the arteries.
Studies done in the middle of  last century on cattle herding tribes from africa, who did not suffer heart attacks, showed the same degree of athersclerosis as americans, who were starting to suffer increasing numbers of heart attacks. What was different was that the africans' arteries were more pliable They were able to widen to compensate for the plaque buildup, while the americans were calcified- they were hard and narrowed as the plaque built up, restricting blood flow.

Blood clots within coronary arteries are most likely due to unstable plaque rupturing (ironically, the cholesterol in these buildups probably makes them more stable. If you understand the role that cholesterol plays in cell structure, this is logical). The more narrow the artery, the more likely a clot will cause a blockage

So a deficency in vitamin K doesn't cause the blood clots, or the atherclerosis, but the narrowed arteries that make the blood clots so dangerous.

It does appear that adding vitamin K to the diet can actually remove this calcification from the arteries, so yes it may seem logical to make up for the deficiency. The flip side as you say is the increased lkely blood of clots.

The first thing that would need to be done is to stabilse the plaque growths, then increase vitamin K.

Unfortunately most of the research concentrates on the false idea that dietary fat and cholesterol is the cause of the problem.

Not too many people will even give this a second thought as it goes against what they have blindly believed for the last 40 odd years (depending on age). One day they will discover that ignorance is not bliss

It great to see someone who takes an active interest in their health.