Tuesday, December 1, 2015

Heart Scan Scores: Then and Now

November and December have and will be filled with a variety of tests, on which I'll be commenting shortly. But I've had a second heart scan and can compare the results to those of the Orange County scan from January, 2010. (The January, 2010 is in the middle, designated with "OC". The November, 2015 score is on the right, designated "MI" for "Millennial Imaging" where the scan was performed.)

First note that the actual number of lesions went down from 10 to 8. (This may, of course, be an artifact owing to different equipment.) Note also that the Calcium Score for the Left Anterior Descending Artery (LAD) actually went down from 283 to 258.2, although the number lesions is the same.  (Again, this could be because of different equipment.)   

For the Right Coronary Artery (RCA), however, although the number of lesions went down from 5 to 3, the score increased from 552 to 654.4. 

While it's my belief that these scores are in "standard form," Orange County included an additional interpretation from 0-100:

0-20 Low
21-40 Moderate
41-70 High
71-100 Very High

On this scale, OC assigned a number of 58, which falls the "High" category.

I am naturally curious about whether this initial risk has changed.  If proportions hold, this risk would increase about 8% in proportion to the increase from 835 to 903.6 or 63, which is still in the "High" category,  but not quite in the "Very High" category. Of course, risk assignment is tricky and may not be linear.

So how do I interpret the two scores, five years apart? I would not make too much of the "fewer" lesions. I am more mindful of the 8% increase in the total  score. I am appreciative of the 9% diminution of the LAD score. I was hopeful that this would be across the board. But this is offset by at nearly 16% jump in the RCA score.  

Still, if the proportions hold, then I would remain in the "High" category and am - in some sense at least - holding my own. One assumes it would be worse without my efforts over the past five years, very likely slipping into the "Very High" category.  But click here for my cardiologist's take five years ago. His thalium stress test actually looks at the blood going through these arteries.  His comment, "no obstruction."

That is, of course, the problem. I am asymptomatic. I am trying to guard against something that statistically could well happen. It goes back to indirect measurements. We don't see the plaque, we see the calcium in a calcium scan. We do see the blood moving in a thalium stress test. "No obstruction" he said.


Artery
# of Lesions OC
Calcium Score OC
# of Lesions MI
Calcium Score MI
LM
0
0
0
0
LAD
5
283
5
258.2
CX
0
0
0
0
RCA
5
552
3
654.4
Total
10
835
8
903.6

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