My 86 year old father was told that he should have a cardiac cath to determine and/or fix a percieved blockage. The cardiaologist based his decision on the degree of chest pain my father had (5 out of 10 ) after exercise on a treadmill. He told my father he probably had 70 % blocage in one of his arteries. Should he have the cardiac cath where they inject the dye and actually visualize the arteries or is that too risky at his age. Thank you