Subject: Re: Thallium Stress test
Forum: The Heart Forum
Topic Area:
Posted by CCF Cardio MD-SGM on December 23, 1997 at 14:29:57:
In Reply to: Thallium Stress test posted by Jim Szarka on December 14, 1997 at 11:56:37:

: In January 1997 I had chest pains and after an angiogram it was discovered that I had a 90% blockage in the LAD with an additional 50% blockage in the same arterary further down. I had been diagnosed with Arterary disease.
They cleared the 90% blockage with a stent angioplasti and left the 50% blockage to be treated with diet, medication and excercise. In late February I had my first Thallium stress test. This served as a reference and they said that it looked good wiht good blood flow to the heart.
In late May I had another thalliun stress as a result of experiencing chest pains. This test showed that I had a slight decresed blood flow to the heart in the area where the stent and blockage exist.
On December 11th I had another thallium stress as a result of some more pains with cold sweats at night. The results of this test seem to be very confusing. This test showed no decreased flow where it was previously ( in the area of the stent/blockage) but showed a decreased flow in the area on the right side of my heart.
My cardiologist seemed some what confused with this analysis. I will be seeing him later this week for more extensive feedback including the possibility of another angiogram. However I have several questions .
Can the thallium test be inaccurate for any reason?
If I do have another blockage on the right side of my heart, could this have happened between the May test and now with nothing showing up on the May test? And why didn't the area of the original decresed blood flow still show up ihn the later test ? It seems as though the decreased blood flow moved from one area to another. Is this possible?
My cholesterol has been good - overall being 160 with HDL at 43 and LDL at 103. I take Toprol, Provachol and aspirin as well as various high doses of vitamin C and E and have been on a low fat diet.
My health insurance company did not allow cadriac rehab since they said my original Thallium test results were good. We have been fighting that battle with them and it is still on-going.
Is there anything you can provide to help clear up some of my confusion as well as recommend a course of action? Thanks

The experience you describe is not as uncommon as you may think. The problem with all the tests that we employ to diagnose and follow-up coronary disease is that they suffer from suboptimal accuracy. Each test has its inherent shortcomings, and no single test provides 100% truthful results. Thus, it is incumbent upon the physician interpreting these studies to use clinical judgment in order to arrive at the most accurate conclusion possible.

Your specific thallium stress test results are inconsistent. Results such as these can either reflect new disease in the Right coronary artery distribution(the right side of the heart) or are simply mistaken. Regarding the are of stent deployment(the Left Anterior Descending distribution) the one abnormal test in May was probably in error, given that your current test shows this area to be normal. Several considerations are critical, however. We know that prognosis is directly related to functional capacity as well as ischemic burden. That is to say that you have a lower risk of repeated heart attack or other undesirable outcomes as the duration and workload of your exercise capacity increase, and as the area of abnormal perfusion(ischemia) decreases. Thus, the results of the thallium need to be taken together with the results of the treadmill(or bike) portion of the test. Some persons cannot perform aerobic exercise due to orthopedic and other problems, and receive medications to simulate exercise during the test. In these persons, the predictive value of the exercise component of the study is lost.

You and your doctor need to discuss the nature of your chest pain, and arrive at a decision as to whether this likely represents angina arising from the heart. Is it similar to the pain you experienced prior to the stent placement? Does this pain worsen with physical activity and respond to rest and nitroglycerine? Or is it "atypical" for pain that arises from coronary disease. Did you experience this pain while recently on the treadmill, for example? Answers to these questions will help in determining the significance of the discrepant thallium results you report.

Yes, it is possible that you have developed new disease in the Right coronary distribution, although the odds of this are reduced if you're following your doctor's advice regarding lifestyle changes, risk factor modification, medication, diet, and exercise. One way to sort this out is to perform another angiogram. This is relatively costly, both in terms of discomfort, a finite but present risk that is involved, as well as financial considerations. However, it may help to sort out this confusion. Another step would be to try another method of stress testing such as stress echocardiography, or a PET scan. Both of which, in good hands, provide similar or more accurate results than the stress thallium tests you have undergone.

If you're in the area, you may consider making an appointment at the Cleveland Clinic for a second opinion. Experts in coronary artery disease management can review your studies and suggest appropriate follow-up at this point. If you wish, you can call 1 800 CCF CARE and ask for desk F25 to make an appointment. Information provided in the Heart Forum is for general purposes only. Specific diagnoses and treatments can only be provided by your physician.

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