Interpreting Nuclear Stress Test Results

[Stan100]

I am a 61 year old male.  I had triple bypass surgery in January 2007.  In October I had a follow-up nuclear stress test (Stress QGS Tetrofosmin).

I would like help interpreting the results of the test.  
The report reads:
“The post Stress Myoview images show a small to moderate territory of decreased perfusion.  This involves the basal and mid inferolateral region and is moderate in severity.  The remaining segments are perfused normally.  The rest Myoview images show partial improvement in perfusion to this region however non-transmural fixed abnormality remains.

Gated wall motion study shows mild basal inferolateral hypokinesis.  The ejection fraction is 60%.

Opinion:  Small to moderate territory of basal and mid inferolateral ischemia.  This is super-imposed on small fixed inferolateral defect suspicious for prior infarction in this territory.  Mild regional wall motion abnormalities.  The ejection fraction is 60%.”

What does all this mean?  At the time of the surgery, it was thought that I had not had a heart attack.  Do these results imply that in fact I had had a heart attack?  

The cardiologist indicated that one of the three new arteries is blocking.  How can this be after only nine months?   What does this mean for future problems with blockages?

Thanks for your advice.

[kenkeith]

..."The cardiologist indicated that one of the three new arteries is blocking.  How can this be after only nine months?   What does this mean for future problems with blockages?"
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Ans. American Association for Thoracic Surgery statistics for saphaneous vein graft (peripheral) has 15 to 30% occlusion rate within in the first year and 50% within 10 years.  Also, AATS was surprised by the degree of damge inflected during conventional procedure.

There can be residual clot and plaque formation from the excised vessel notwithstanding preoperative procedures.  And the vessel can be improper caliber.  A thoracic vessel (mammary) has a better record of success and can last a lifetime.

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"Opinion:  Small to moderate territory of basal and mid inferolateral ischemia.  This is super-imposed on small fixed inferolateral defect suspicious for prior infarction in this territory.  Mild regional wall motion abnormalities.  The ejection fraction is 60%.”
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Ans.  There is some blockage in the area cited.  Mild regional wall motion abnormalities is consistent with a prior heart attack.  An estimate of an EF 60% is not consistant with a prior heart attack or there is very little heart muscle damage from myocardial infarction (heart attack).   Normal EF is 55 to 75% and indicates the contractile strength with each heart beat.  Damaged heart muscle from an MI decreases contractions and lowers EF.

Sometimes there can be heart muscle damage from sustained ischemia (lack of blood supply) and the heart cells are in hibernation or stunned and can be activated with supply of an adequate oxygenated blood.  Also, if an MI is quickly treated there can be a preservation of heart muscle.