My stress test was abnormal dr said when i was in the middle of the test my blood pressure drop from 180 to 100 and don't know why nuclear test normal?

Heart cath. ASAP!: A drop in blood pressure during a stress test of more than 10 points is a very ominous sign, and you dropped 80 points! it usually means the left main (widow maker) or all 3 arteries are blocked if the aortic valve is not blocked. Please get a cardiac catheterization quickly! your first symptom might be sudden death! don't wait for this!

Balanced ischemia!: When the nuclear test is "normal", it means there is no difference in the blood flow to all 3 coronary arteries, what we call "balanced ischemia". Please see my other answer, you need a cardiac catheterization asap!