To Clot or not to Clot

A recent blog discussed the fact that clots cause myocardial syndromes. Stable clots induce STEMI and unstable or waxing and waning clots cause ACS or acute coronary syndrome. The differences between the unstable and stable clots are not fully understood but much of the difference is due to platelet activation and much of that activation is due to smoking.The question has now become why do the clots form? What does the inside of the artery look like and can these changes be predicted and prevented. I have blogged before that a large portion perhaps up to 40% of myocardial infarctions is not caused by severely diseased arteries. What I mean is the extent of blockage in these arteries is less than 50% of the lumen. It was believed that the arteries in the less severe disease states suffered from edge “cracking”. When the normal artery meets the abnormal plaque a fragile zone is created and under the right circumstances ruptures. This micro crack exposes the blood to abnormal components and the clotting cascade starts.

A well known phenomenon is that an individual with acute coronary syndrome will often have several plaques that look “angry” at cath and it can be difficult to know exactly which one to fix.

Dr. Renu Virmani is a cardiac pathologist and has spent her life looking at coronary arteries that have caused syndromes and death. Unfortunately, if she is looking at someone’s coronary arteries that patient has died from their problem. Someone kindly consented for an autopsy. This work has been invaluable in the everyday practice of cardiology as it has allowed us to learn and modify our techniques. She was among the first to recognize and characterize late stent thrombosis and to give us an understanding of the incomplete reendothelialization that occurs with drug stents and to help us understand that longer use of Plavix is warranted.

Published in J Am Coll Cardiol 2009;DOI:10.1016 a new study again points to our continued learning about the relationships of thrombus to plaque morphology.

Next…what we learned.

Tags: Acute Coronary Syndrome, clots, myocardial syndromes, Plavix

This entry was posted on Tuesday, January 5th, 2010 at 12:22 pm and is filed under Acute Coronary Syndrome, Myocardial Infarction. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.