Here is a review of how CAD in women can be different from CAD in men.
It now appears that a new, possibly more significant difference has turned up. Researchers have recently discovered that in younger women who have died suddenly from coronary thrombosis (blood clots that form in the coronary artery and obstruct blood flow), these fatal blood clots can be quite different than those in men who have suffered sudden death.
How Coronary Thrombosis Is Thought to Occur
Coronary thrombosis is generally thought to occur when an atherosclerotic plaque in a coronary artery suddenly ruptures. The rupture exposes the "gunk" inside the plaque (cholesterol, calcium, inflammatory cells, and other material) to the bloodstream - and this can trigger a clot to form.
The coronary artery can then become suddenly obstructed by the clot, shutting off blood flow to the heart muscle. This obstruction can lead to a heart attack (also known as a myocardial infarction), and all too often, can produce sudden cardiac death.
New Difference In CAD In Women
The new evidence suggests that in women under 50 years of age, plaque rupture is often not the cause of the blood clot. Instead, the clot may be triggered by erosion of the blood vessel wall.
What's the difference between a rupture and an erosion? Well, a rupture of a plaque is like a pimple that pops open. (In fact, the stuff inside a typical zit is not entirely unlike the stuff inside an atherosclerotic plaque.) But an erosion is more like a shallow ulcer - the plaque associated with an erosion may be quite small, or there may not be a plaque at all.
What The New Finding Means
This new information may partially explain two features of CAD in women that have puzzled cardiologists for years:
- First, it may explain why younger women with coronary thrombosis tend to do worse than men. "Erosion clots" tend to be "older" than "rupture clots." That is, they appear to form less suddenly, which means the clots have time to mature.
It has been known for years that clots that form more gradually are more dangerous (they produce death more often) than more acute clots.
So if women are more likely to have clots due to erosions, that fact may partially explain the worse outcomes.
- Second, erosions are more likely than ruptures to occur in coronary arteries that appear to be relatively normal during cardiac catheterization or stress/thallium testing - that is, in arteries where there are no "significant" atherosclerotic plaques.
It is also thought that erosions may be caused by repeated spasms of the coronary arteries, such as in Prinzmetal's angina.
So the fact that blood clots in women can be caused by erosion may help explain why women with apparently with "normal" coronary arteries can still have heart attacks.
At this point, the observation that erosion-induced clots may be an important cause of coronary thrombosis in women provides an interesting and likely important new piece of information about CAD in women.
It is becoming increasingly obvious that CAD in younger women is very often a different disease than the "classic CAD" that is seen in men and in older women. The recognition of this fact is leading, at last, to efforts to gain a full understanding of those differences and to develop more effective strategies for treatment.
Sources:
Kramer MCA, Rittersma SZH, de Winter RJ, et al. Relationship of thrombus healing to underlying plaque morphology in sudden coronary death. J Am Coll Cardiol 2009; DOI:10.1016/j.jacc.2009.09.007.
