Question:
Cardiolite Stress Test ?
Answer:
The purpose of the Cardiolite stress test in this circumstance would
be to evaluate the hemodynamic significance of the lesions found in
your coronary arteries. In other words, do the lesions significantly
reduce the supply of blood to parts of your heart to the point where
they are at risk of being infarcted.
The location of the lesions in your coronary arteries are of great
concern. The left main and LAD vessels supply blood to a very large
portion of your heart. An infarction of those areas could be extremely
debilitating or fatal. So, they are trying to be very careful with you.
When lesions develop in coronary arteries, the heart can develop
collateral circulation to the affected areas. In other words, the
blood can arrive at the heart muscle by different routes, which might
be hard to demonstrate with coronary artery angiography.
Cardiolite stress imaging visualizes the heart in a different way.
The situation is seen a little further "down stream." The images show
the perfusion of blood in the muscle of the heart. The arterial lesions
themselves are not seen, only their effect on myocardial perfusion.
If the Cardiolite stress images do not show any significant defects,
your cardiologist can have more confidence that you are not at risk
for an infarction within the next few years. With that confidence,
he would be more likely to be comfortable recommending a non-surgical
approach. It sounds like you have done admirably with that approach
so far, but it doesn't mean that you are not still in a high risk state.
The stress test you already had suggested that the lesions are
significant. But, stress ECG tests are subject to false results in some
circumstances. A stress test with Cardiolite imaging increases the
reliability of the test to something in the 90%+ range (it is generally
agreed).
The Cardiolite stress test is not particularly difficult to tolerate. It
will be a lot like the stress ECG you had with the addition of an IV line
for injecting the radioactive tracers (Cardiolite and/or Thallium), and
a little time lieing down and holding still while the scintillation camera
makes pictures of where the tracers went in your heart. It is certainly
not as difficult as a heart catheterization.
You may indeed be "at some risk for a significant event" but bypass will not
prevent said event. "Events" are due to a sudden rupture of an
atherosclerotic plaque. Rupture is more likely to happen at locations in the
coronary artery with early unstable (but reversible) plaque which may look
perfectly normal on the angiogram. The obstructions causing the abnormal
stress test will not cause an event since they are already completely
occluded. A nuclear scan is expensive and will only confirm what you already
know. A bypass would only be indicated if you had intractable exertional
symptoms. No pain, no bypass. You are doing the right thing by changing you
lifestyle. This is much more likely to prevent an event than bypass. You
will not be running any more marathons but you can live quite comfortably
with your disease even if the arteries don't open up with you noninvasive
treatment.
