Editing Vulnerable plaque (section)

{{Short description|Plaque vulnerable to stroke or ischemia}}
{{Medref|date=November 2021}}

A '''vulnerable plaque''' is a kind of [[atheromatous plaque]] – a collection of [[white blood cell]]s (primarily [[macrophage]]s) and [[lipids]] (including [[cholesterol]]) in the wall of an [[artery]] – that is particularly unstable and prone to produce sudden major problems such as a [[myocardial infarction|heart attack]] or [[stroke]].<ref>{{Cite web |title=Atherosclerotic plaque in arteries overview • Heart Research Institute |url=https://www.hri.org.au/health/learn/cardiovascular-disease/atherosclerotic-plaque |access-date=2024-08-29 |website=Heart Research Institute |language=en-AU}}</ref>

The defining characteristics of a vulnerable plaque include but are not limited to: a thin [[fibrous cap]], large lipid-rich necrotic core, increased plaque inflammation, positive vascular remodeling, increased [[vasa vasorum|vasa-vasorum]] [[neovascularization]], and intra-plaque hemorrhage.<ref>{{Cite journal | last1 = Moreno | first1 = P. R. | title = Vulnerable Plaque: Definition, Diagnosis, and Treatment | doi = 10.1016/j.ccl.2009.09.008 | journal = Cardiology Clinics | volume = 28 | issue = 1 | pages = 1–30 | year = 2010 | pmid = 19962047 }}</ref> These characteristics together with the usual hemodynamic pulsating expansion during [[Systole (medicine)|systole]] and elastic recoil contraction during [[diastole]] contribute to a high mechanical stress zone on the fibrous cap of the [[atheroma]], making it prone to rupture. Increased hemodynamic stress, e.g. increased blood pressure, especially pulse pressure (systolic blood pressure vs. diastolic blood pressure difference), correlates with increased rates of major cardiovascular events associated with exercise, especially exercise beyond levels the individual does routinely.

Generally an atheroma becomes vulnerable if it grows more rapidly and has a thin cover separating it from the bloodstream inside the arterial [[lumen (anatomy)|lumen]]. Tearing of the cover is called ''plaque rupture''. However, a repeated atheroma rupture and healing is one of the mechanisms, perhaps the dominant one, that creates [[artery]] [[stenosis]].