Can a high INR reading affect blood pressure?

SHOULDN'T. A high inr (protime) is usually due to an excess of Coumadin (warfarin) relative to vitamin k intake. The 'clotting system' of proteins (produced by the liver) has no affect on blood pressure (BP) , generally. BP is influenced by other factors: salt intake, lack of exercise, stress, pain ...
No, but high INR. by itself is a serious issue and you should consult your doctor.