Editing Angina (section)

===Microvascular angina===

{{main|Microvascular angina}}

[[Microvascular angina]], also known as ''cardiac syndrome X'', is characterized by angina-like chest pain, in the context of normal epicardial coronary arteries (the largest vessels on the surface of the heart, prior to significant branching) on [[angiography]]. The original definition of cardiac syndrome X also mandated that ischemic changes on exercise (despite normal coronary arteries) were displayed, as shown on [[cardiac stress test]]s.<ref>{{cite book| veditors = Kaski JC |title=Chest pain with normal coronary angiograms: pathogenesis, diagnosis and management| date=1999| publisher=Kluwer| location=Boston| isbn=978-0-7923-8421-2| pages=5–6}}</ref> The primary cause of microvascular angina is unknown, but factors apparently involved are endothelial dysfunction and reduced flow (perhaps due to spasm) in the tiny "resistance" blood vessels of the heart.<ref>Guyton, Arthur. "Textbook of Medical Physiology" 11th edition. Philadelphia; Elsevier, 2006.{{page needed|date=February 2013}}</ref> Since microvascular angina is not characterized by major arterial blockages, it is harder to recognize and diagnose.<ref name="HeartHealthyWomen.org">{{cite web
 |title=Cardiac Syndrome X |date=14 August 2022 |publisher=HeartHealthyWomen.org |url=http://www.hearthealthywomen.org/cardiovascular-disease/cardiac-syndrome-x/cardiac-syndrome-x.html}}{{MEDRS|date=February 2013}}</ref><ref>{{cite web| url=http://www.americanheart.org/presenter.jhtml?identifier=4591 |title=Heart Attack and Angina Statistics. |access-date=2010-04-13 |url-status = dead|archive-url=https://web.archive.org/web/20100413012434/http://www.americanheart.org/presenter.jhtml?identifier=4591 |archive-date=2010-04-13 }} {{failed verification|date=March 2013}}.</ref><ref>
{{cite web |title=Angina |publisher=Texas Heart Institute |date=October 2012 |url=http://www.texasheartinstitute.org/hic/topics/cond/angina.cfm |access-date=2010-05-04 |archive-url=https://web.archive.org/web/20140817121322/http://www.texasheartinstitute.org/HIC/Topics/Cond/Angina.cfm |archive-date=2014-08-17 |url-status = dead}}
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Microvascular angina was previously considered a rather benign condition, but more recent data has changed this attitude. Studies, including the Women's Ischemia Syndrome Evaluation (WISE), suggest that microvascular angina is part of the pathophysiology of ischemic heart disease, perhaps explaining the higher rates of angina in females than in males, as well as their predilection towards [[ischemia]] and acute coronary syndromes in the absence of obstructive coronary artery disease.<ref>{{cite journal | vauthors = Gulati M, Shaw LJ, Bairey Merz CN | title = Myocardial ischemia in women: lessons from the NHLBI WISE study | journal = Clinical Cardiology | volume = 35 | issue = 3 | pages = 141–8 | date = March 2012 | pmid = 22389117 | pmc = 3297966 | doi = 10.1002/clc.21966 }}</ref>