Coronary arteries aren't what they seem

12. November 2007 William Davis (5)
Why do stress tests so often fail to detect coronary atherosclerotic plaque? Why do even heart catheterizations--the "gold standard"--fail to disclose the full extent of plaque within the walls of coronary arteries?

We owe much of the explanation of these phenomena to Dr. Seymour Glagov, retired professor of pathology at the University of Chicago.



When studying the coronary arteries of people who died, he observed that people commonly had plenty of atherosclerotic plaque lining the artery wall, yet it did not necessarily impinge on the artery "lumen," or the internal path for blood to flow.

The only time the lumen became obstructed by plaque was when either 1) plaque grew to overwhelming levels and was severe and extensive, or 2) when a plaque had "ruptured," meaning its thin covering had been penetrated and eroded by the underlying plaque tissue like a volcano emerging from the surface and erupting.

This groundbreaking observation, now dubbed "the Glagov phenomenon," explains why someone can have a normal stress test on Tuesday but erupt a plaque on Wednesday.

The Glagov phenomenon also explains why heart scans can detect plaque when both stress tests and heart catheterizations fail to do so. Many physicians will then interpret this to mean that the heart scan was wrong. With the Glagov phenomenon in mind, you can see that the heart scan is not wrong, it is simply detecting coronary atherosclerotic plaque at a stage that is not yet detectable by the other methods.

In the illustration, you can see that the lumen of the vessel is maintained--despite the artery on the left having minimal plaque, the artery on the right containing moderate plaque. If either artery were examined by a test that relies on blood flow--stress test or heart catheterization--both would appear normal. But a test that examines the artery wall, such as a heart scan, would readily detect the artery on the right and probably even the artery on the left.




I am very grateful to Dr. Glagov and his insight into this important process. Otherwise, we might still be floundering around trying to understand the apparent discrepances between these tests that simply provide different perspectives on the same problem.
Tags :

Comments (5) -

  • Anonymous

    11/13/2007 1:04:00 AM |

    I saw a new small 2 pound ultrasound machine for detecting plaque in neck arteries just hit the market place.  Article was at: http://www.newstarget.com/022212.html

    It sounds exciting that something like this would be easily accessible - as the author speculates.  Do you think this new small devise will be helpful - if one has plaque in neck arteries does that typically also mean plaque in the heart?

  • Dr. Davis

    11/13/2007 2:54:00 AM |

    Actually, I purchased one of these devices about 7 years ago. The data is reasonably well worked out: carotid ultrasound for a measure called intima-media thickness is a reasonable second choice to coronary plaque measurement. It can be useful to augment information from direct coronary scoring, or when heart scanning is impossible, e.g, some people after bypass surgery.

  • Anonymous

    11/13/2007 7:11:00 PM |

    You've been concentrating a lot on coronary arteries, and the effect of plaque build up. What about the valves of the heart? Can plaque build up on, or otherwise affect them?

  • Dr. Davis

    11/13/2007 10:08:00 PM |

    This blog and the accompanying website, www.trackyourplaque.com, are intended to focus on coronary issues.

    However, I have been seeing aortic valve disease actually improve with vitamin D. Please see my blog post, Valve disease and vitamin D at http://heartscanblog.blogspot.com/search/label/Valve%20disease%20and%20vitamin%20D.

  • buy jeans

    11/3/2010 10:15:10 PM |

    When studying the coronary arteries of people who died, he observed that people commonly had plenty of atherosclerotic plaque lining the artery wall, yet it did not necessarily impinge on the artery "lumen," or the internal path for blood to flow.

Add comment

Loading
Track Your Plaque: Safer at any score

Track Your Plaque: Safer at any score

11. November 2009 William Davis (0)
Imagine two people.

Tom is a 50-year old man. Tom's initial heart scan score was 500--a concerning score that carries a 5% risk for heart attack per year.

Harry is also 50 years old. His heart scan score is 100--also a concerning score, but not to the same degree as Tom's much higher score.

Tom follows the Track Your Plaque program. He achieves the 60:60:60 lipid targets; chooses healthy foods, including elimination of wheat; takes fish oil at a therapeutic dose; increase his blood vitamin D level to 60-70 ng/ml, etc. One year later, Tom's heart scan score is 400, representing a 20% reduction from his starting score.

Harry, on the other hand, doesn't understand the implications of his score. Neither does his doctor. He's casually provided a prescription for a cholesterol drug by his doctor, a brief admonition to follow a low-fat diet, and little else. One year later, Harry's heart scan score is 200, a doubling (100% increase) of the original score.

At this point, we're left with Tom having a score of 400, Harry with a score of 200. That is, Tom has twice Harry's score, 200 points higher. Who's better off?

Tom with the score of 400 is better off. Even though he has a significantly higher score, Tom's plaque is regressing. Tom's plaque is therefore quiescent with active components being extracted, inflammation subsiding, the artery in a more relaxed state, etc.

Harry's plaque, in contrast, is active and growing: inflammatory cells are abundant and producing enzymes that degrade supportive tissue, constrictive factors are released that cause the artery to pinch partially closed, fatty materials accumulate and trigger a cascade of abnormal responses.

So it's not just the score--the quantity of atherosclerotic plaque present--but the state of activity of the plaque: Is it growing, is it being reduced? Is there escalating or subsiding inflammation? Is plaque filled with degradative enzymes or quiescent?

Following the Track Your Plaque program therefore leads us to the notion that it's not the score that's most important; the most important thing is what you're doing about it. We sometimes say that Track Your Plaque makes you safer at any score.
Tags :

Add comment

Loading
Cheerios and heart health

Cheerios and heart health

22. April 2008 William Davis (11)


Anna responded to the Heart Scan Blog post, Can you say "sugar"? with the following wonderfully telling comment:

A measured bowl of Cheerios and a bit of milk (whole, because it's what I had), equal to 75 grams of carbohydrate, gave me the highest ever blood glucose reading from a food (not counting glucose solution from a Glucose Tolerance Test). I was attempting a "homemade" version of a 3 hr GTT before going to my doctor with my concerns about my BG.

My BG started to rise very fast within 15 minutes after eating the cereal, peaked at about 250 mg/dL at 45 minutes, then slowly dropped. By about 60-75 minutes, I experienced strong hunger and carb cravings as the BG began to slowly drop, and by about 2.5 hours after eating, my BG had suddenly dropped quite low (in the low 70s) and I had developed a nasty hypoglycemic feeling (shaky, irritable, craving sugary foods, headache, etc.).

It's hard for me to see "heart healthy" Cheerios (or any other highly processed breakfast cereal) as anything other than a bowl of pre-digested sugar that contributes to roller coaster blood glucose and insulin levels, which a great way to start anyone's day. Certainly, I don't do well with Cheerios because I clearly have a damaged glucose regulatory system (probably a diminished or absent first phase insulin response, but I can't imagine that it is doing any good for people with healthy glucose regulation, either.

I banned prepared cold cereals from our house. If my 9 yr old son gets cereal at all at home, it's whole groats (not even rolled or steel cut because those aren't truly "whole grain" anymore), soaked overnight in some water and a tsp of plain yogurt (soaking neutralizes phytates and reduces cooking time), then cooked about 8-10 minutes (water added as necessary). Sometimes I add a bit of quinoa or almond meal prior to soaking to boost the protein content a bit. I garnish with a pat of butter, some heavy cream, and a dusting of cinnamon. If I'm feeling *really* indulgent, I drizzle about 1 tsp of Grade B maple syrup on top (Grade B is stronger in flavor and so less can be used). I don't eat this cereal myself, and truthfully, I'd rather my son not, either, but he sometimes wants cereal. It's the least damaging compromise I can come up with that we can both live with.


I have also seen diabetic effects from Cheerios: rises in blood sugar, exagerration of small LDL, drops in HDL, rises in triglycerides. Yes, it may reduce LDL a small quantity, but so what?

The Cheerios "heart healthy" claim is based on a piece of research apparently performed by Dr. Donald Hunninghake at the University of Minnesota and reported in 1998:

A study conducted at the University of Minnesota Heart Disease Prevention Clinic and published as "Cholesterol-Lowering Benefits of a Whole Grain Oat Ready-to-Eat Cereal" in the May issue of the Nutrition in Clinical Care journal in 1998, showed that people can lower their blood cholesterol by an average of 3.8% over six weeks by enjoying 3 cups of cold cereal made with 100% whole grain oats everyday as part of the meals and snacks in a healthy lower-fat diet.

(Unfortunately, I could not locate the actual publication. It doesn't mean it doesn't exist; I just couldn't locate it. Perhaps it's in a small journal not entered into the online publication database.)

The purported effects of Cheerios should not be confused with that of actual, intact oat bran, as suggested by studies such as those of Brenda Davy et al, High-fiber oat cereal compared with wheat cereal consumption favorably alters LDL-cholesterol subclass and particle numbers in middle-aged and older men, in which significant reductions in LDL particle number and small LDL (NMR) were obtained. (This study was also supported by Quaker Oats.) Several studies have shown that oat bran does indeed reduce LDL cholesterol, sometimes as much as 30-50 mg/dl. Cheerios can not even come close to this.

If Cheerios were nothing more than finely pulverized oats, then perhaps it wouldn't be so bad. But add corn starch and sugar, and you have ingredients that have potential to distort LDL particle size and yield blood sugar-escalating effects like those described by Anna.

The gravity of perpetuating these myths is brought home by a testimonial posted on the website for Cheerios:

“I had unexpected open heart surgery a year ago. As I adopted heart health habits during my recovery, I realized that I should have been eating the Cheerios cereal I carried around in a plastic baggie so many years for my kids!”

Beverly
Scotch Plains, NJ


It makes me shudder.


Copyright 2008 William Davis, MD
Tags :

Comments (11) -

  • Susan

    4/22/2008 1:13:00 PM |

    I did a little digging and found this press release from General Mills on the study: http://www.newswise.com/articles/view/?id=CHOLEST.GNM. It's interesting that the study was carried out at the University of Minnesota. Guess where General Mills is headquartered? Yep, in Minneapolis.

    The journal in question, Nutrition in Clinical Care, was published by Tufts University and the Friedman School of Nutrition Science and Policy between 1998 and 2005. The original publisher was Blackwell (Volumes 1–5), and it was then picked up by the International Life Sciences Institute (whose members include Bayer, Cadbury, Coca-Coa, Kellogg's, Kraft, Heinz, McNeil, Mead Johnson, National Starch Food (I love that one), Pfizer ... well you get the picture).

    A search on the name of the principal researcher is equally interesting.

  • Anonymous

    4/22/2008 1:19:00 PM |

    A little different comment than what is mentioned on this post, but a cousin was told by her doctor yesterday that she should take vitamin D3, K2, fish oil, and stop eating sugary foods.  This wasn't said for heart health though.  She had a nasty accident when riding a horse and broke several bones.  

    I'm going to mail her a get well package, include the mentioned supplements plus throw in some magnesium. Good to see another opened minded doctor prescribing what ever works.  My typical experience has been that doctors don't mentioning supplements.

  • Dr. William Davis

    4/22/2008 11:03:00 PM |

    Wow, Susan! Great info!

    I wasn't aware of the "interesting" bloodline of the journal.

    Thanks!

  • Paul Kelly - 95.1 WAYV

    4/24/2008 3:27:00 PM |

    Hi Dr. Davis,

    You wrote that several studies have shown that oat bran does indeed reduce LDL cholesterol, sometimes as much as 30-50 mg/dl.

    Where would I find a good oat bran? Also - isn't oat bran pretty "carby"? I typically have to keep my daily intake of carbs between 40 and 60 grams to avoid gaining weight. Does oat bran fit into a low-carb way of eating?

    Thanks in advance for your reply!

    Paul

  • Cindy Moore

    5/5/2008 11:42:00 PM |

    "people can lower their blood cholesterol by an average of 3.8% over six weeks by enjoying 3 cups of cold cereal made with 100% whole grain oats everyday as part of the meals and snacks in a healthy lower-fat diet."

    THREE Cups a day?!?! That's a hefty dose! A lot of carbage for a little "benefit". I guess the particle size would completely negate any "benefit"?

  • Hal

    9/2/2009 8:29:30 PM |

    When I first started testing my BG in the first few days I discovered that Cheerios would cause my numbers to spike.  The numbers I saw that day are the highest readings I have ever had.  Needless to say that was the last time I ate cheerios.

    The sad thing was that based on the advertising I thought that I was doing the right thing by eating cheerios.  Of course I know know better.

  • baby eczema

    9/9/2010 4:59:59 AM |

    Add a diet low in processed food and a good 'lifestyle' (don't smoke, control waist size, manage stress well, some exercise) and you will improve general health and help prevent heart disease.

  • Michal

    9/17/2010 9:01:32 PM |

    Nice blog !
    Kamagra Oral Jelly Some patients struggle to swallow medicine in tablet form A new popular form of Kamagra is now available in Oral Jelly sachets The.

  • buy jeans

    11/3/2010 2:19:52 PM |

    I have also seen diabetic effects from Cheerios: rises in blood sugar, exagerration of small LDL, drops in HDL, rises in triglycerides. Yes, it may reduce LDL a small quantity, but so what?

  • Hearing Aids

    1/22/2011 8:52:03 AM |

    Superb blog post, I have book marked this internet site so ideally I’ll see much more on this subject in the foreseeable future!

  • online viagra

    3/30/2011 5:25:28 AM |

    Good information about Heart. In the modern world many person are suffering from hart problem in very early age for such people it is very nice articles.

    Thanks a lot for this nice informative post.................


    Smith ALan

Add comment

Loading