Heart Scan Curiosities #7

25. June 2007 William Davis (1)



Here's a situation that crops up once in a while, occurring in perhaps 2% of heart scans.

The white within the circled area represents calcium, and thereby atherosclerotic plaque, situated immediately at the "mouth", or opening, of the the right coronary artery. What is somewhat unusual is that this plaque is not principally coronary, but aortic. That is, the plaque is mostly situated in the large vessel called the aorta. The three coronary arteries arise from the aorta.

In this instance, the aortic plaque involves the mouth of the right coronary artery. (In views not shown, the plaque also extends into the artery as well.) I call this a "double whammy" because the same plaque can post risk for heart attack and stroke.

Generally, aortic plaques pose risk for stroke. When aortic plaque fragments, little bits and pieces can travel upward to the brain and block an artery, thus a stroke.

In the coronaries, disrupted ("ruptured") plaques don't generally shower debris, but permit blood clot formation, resulting in heart attack.

This plaque, however, poses the theoretical risk of both heart attack and stroke because of its strategic location.

Should a plaque like this be handled any differently? I don't think so. But it does provide another reason to take atherosclerotic plaque in any artery seriously.
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  • Anonymous

    11/12/2008 5:12:00 AM |

    I just had my first heart scan at Boulder, CO.  My heart scan score was zero, but my descending aorta showed as mildly calcified.

    I wonder what conditions determine whether plaque builds up in the coronary arteries versus in the aorta.  

    And I also wonder how mildly calcified would score if it was in the coronary arteries rather than in the aorta.  I know how to interpret the zero heart scan score, but I don't know how to interpret the mildly calcified aorta.  Since it is in the descending aorta, I believe it is less dangerous than the case discussed here.

    Lynn

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Do stents kill?

Do stents kill?

6. February 2007 William Davis (5)
There's apparently a lively conversation going on at the HeartHawk Blog (www.hearthawk.blogspot.com). Among the hot topics raised was just how bad it is to have a stent.

I think that my comments some time back may have started this controversy. I've lately noticed that having a stent screws up your heart scan scoring in the vicinity of the stent. I was referring to the fact that I've now seen several people in the Track Your Plaque program do everything right and then show what I call "regional reversal": unstented arteries show dramatic drops in score of 18-30%, but the artery with a stent shows significant increase in score.

This is consistent with what we observe in the world outside Track Your Plaque when stents are inserted. Someone will get a stent, for instance, in the left anterior descending artery. A year later, there will be a "new" plaque at the mouth of the stent or just beyond the far end. This is generally treated by inserting another stent. Use of a drug-coated stent seems to have no effect on this issue.

Now, my smart friends in the Track Your Plaque program would immediately ask, "Does this mean you continually end up chasing these plaques that arise as a result of stents? Do you create an endless loop of procedures?"

Thankfully, the majority of times you do not. Rarely, this does happen and can lead to need for bypass surgery to circumvent the response. But it is unusual. The tissue that grows above and below stents does seem to be unusually impervious to the preventive efforts we institute.

Perhaps there's some new supplement, medication, or other strategy that will address this curious new brand of plaque growth. Until then, you and I can only take advantage of what is known. If it's any consolation, the plaque that seems to grow because of a previously inserted stent seems to lack the plaque "rupture" capacity of "naturally-occuring" plaque. It is, indeed, somehow different. It is more benign, less likely to cause heart attack. It's always been my feeling that this tissue behaves more like the "scar" tissue that grows within stents, causing "re-stenosis", a more benign, less rupture-prone kind of tissue.
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  • madcook

    2/6/2007 5:17:00 AM |

    "If it's any consolation, the plaque that seems to grow because of a previously inserted stent seems to lack the plaque "rupture" capacity of "naturally-occuring" plaque. It is, indeed, somehow different. It is more benign, less likely to cause heart attack."

    Dr. Davis:

    You'll pardon my obvious question:  Has anybody actually looked at this phenomenon both in structure and composition at (pardon the word) autopsy?  I would wonder if it's a hyper-reaction to a foreign object, a kind of 'normal' scarring, as you mentioned, or something else.  Obviously there is calcium in this plaque, else it wouldn't be visible on scan. Very curious...

    madcook

  • Dr. Davis

    2/6/2007 8:46:00 PM |

    Madcook--
    The phenomenon is known as "edge restenosis". When examined at autopsy, or in years past when plaque was actually extracted by procedures like directional atherectomy, the material is the same as that occuring within the stent, known as "neointimal hyperplasia."

    The million dollar question is: Can anything modify neointimal hyperplasia? This is the whole dilemma of stent restenosis, the growth of tissue into stents. Of course, the procedural answer tends to involve drug coated stents. However, I know of no specific preventive strategy that has demonstrated substantial impact on the edge restenosis phemenonon. I've tried several agents, including cilostazol, which holds modest promise.

  • madcook

    2/6/2007 11:14:00 PM |

    Thank you for that information... I look forward to hearing more about the use of these agents as time goes by.

    "Of course, the procedural answer tends to involve drug coated stents."

    I just wonder how many people, who 'flunk' a treadmill test, or having an 'equivocal' result, end up in the cath lab and emerge with stent(s)... Are they _really_ aware beforehand that a lot of stent use is "off label" and they just might end up with a year or two (or a lifetime) on Plavix and aspirin?

    I lasted a week on Plavix before I refused anymore... after nearly bleeding to death in the kitchen from a cut (where else would a madcook hang out?).  But then I was very lucky, too as I escaped the cath lab without needing stenting.  A rare event I understand... and aspirin will always be my daily friend (along with most of the other TYP recommendations).

    Regards and thank you for the Heart Scan Blog.  It is a tremendous resource and very informative.

    madcook

  • John Townsend

    2/7/2007 9:15:00 PM |

    RE: "A year later, there will be a "new" plaque at the mouth of the stent or just beyond the far end."

    I'm curious whether or not this is a regular or typical occurrence and if there are symptoms one should be sensitive to that indicate such a development. Also does the size of the stent have a baring on the condition? Does vigorous exercise exasperate the condition?

    I appreciate your blog. It's very informative and helpful.

  • Dr. Davis

    2/7/2007 9:42:00 PM |

    John--
    It is, unfortunately, a very common occurrence, though the majority of times it does not result in any specific symptom or clinical consequence. Among the 30% or so of people who do re-develop chest pain, breathlessness, or have a new abnormality on a stress test, most of the time another stent is implanted at the area of tissue growth.

    Though this is really outside the realm of the Track Your Plaque program, it is yielding confusing results for people who engage in the program yet have a stent or two. It's my believe that the stent modifies the process of scoring in the stented artery. That's why we can see score reduction in arteries without stents, while the artery with a stent shows substantial increase in score.

    The larger the artery, the less likely this occurs. Large means 3.5 mm or greater in diameter.

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