Stress test

My father is 69 years old. 3.5 years ago (spring 1996),he underwent an angiogram where it was detected that he has 40% blockage in the artery on the
     left side of his heart, very close to the main artery,and 60% and 50% blockage in two places in the right coronary artery. Since then, he has been aunder
     medication,and underwent 4 stress tests, one each year (autumn 1996,1997,1998 and 1999). The first two tests were negative for ischemia, the one
     performed in 1998 showed some ischemia,but according to the doctor, it was nothing to worry about, almost negligible. However, in the 1999 stress
     test,performed a few days ago, the doctor diagnosed that the ischemia has "grown". However, he noted that the recovery time was very good,(about 3 mins). So,the doctor suggested that we undergo another test( thalium i think) and
     maybe an angiogram again. What i want is to know your medical opinion, based on your expertise. Is it possible that my father situtation has deteriorated
     so much, that he has to undergo a heart surgery? Also,is the 40% blockage near the main artery bad? I am asking,because the doctors said 3 years ago
     that the blockages in the right coronary were not to be a very big worry.
     Thank you in advance,
     Petros

PS: I forgot to menton,that since last year, my father gained 6 kg in weight. Could it be, that the blockages remain the same, but ischemia apeeared
due to the higher workload? (he had to carry "more " weight during exercise)
Thanks again

[Cleveland Clinic, MD]

It's hard to give an opinion without seeing the tests themselves but in general no intervention (i.e. angioplasty or bypass surgery) needs to be done until blockages are at least 80%.  Blockages in the right artery are less concerning than ones in the left but still need treated if they are causing symptoms.  Hope this answers your questions.  Feel free to write back with additional questions.