![]() This is thought to be the result of the autonomous nervous system involvement in the pathophysiology of CAS. and especially while performing light exercises. Unlike vasovagal symptoms such as nausea, vomiting, and cold sweat, the circadian variability characteristic for CAS occurs regularly at rest and early in the morning between midnight and 5 a.m. Therefore, a prolonged CAS accelerates the progression of atherosclerosis and triggers thrombus formation by platelets activation. Nonetheless, silent ischemia often found with a short episode of CAS is twice as prevalent as angina pectoris and chest pain, which is considered to be the most common feature related to CAS. The length of the CAS episode is important in terms of the large variance of clinical manifestations from the asymptomatic event to the different aspects of ACS (unstable angina, NSTEMI, and STEMI) and sudden cardiac death. This article is an update review of CAS, highlighting the unfamiliar subclinical entity known as “Kounis syndrome” and the latest development in the diagnostic modalities such as CMRI, IVUS, and OCT. As a result, CAS acquired an essential contributing role in ischemic heart disease pathophysiology. Recently, the coronary artery spasm hypothesis was confirmed and demonstrated in several experimental studies, especially after the introduction of either the provocative test that induces vasospasm or coronary angiography that illustrates spasm on the epicardial coronary artery in patients with vasospastic angina. Thus, they proposed an underlying culprit vasospasm reducing blood supply to a localized myocardial area that explains the remarkable accompanied electrical changes such as transient ST segment elevation or depression in the corresponding leads. by describing a nonexertional angina occurring at rest or during regular daily activities, which could not be explained by an increase in myocardial oxygen demand unlike the classical angina of Heberden induced by an emotional or physical stress and relieved by exercise cessation or nitrates. The concept of CAS was first postulated by Prinzmetal et al. Several features were attributed to this complex ischemic entity over time passing by “A variant form of angina pectoris or variant angina”, “variant of the variant”, “coronary vasospastic angina”, “a false-positive STEMI”, and “forgotten coronary disorder”. Combination therapies are proposed for refractory cases.Ĭoronary artery spasm (CAS), which is a reversible vasoconstriction driven by a spontaneous vascular smooth muscle hypercontractility and vascular wall hypertonicity narrowing the lumen of normal or atherosclerotic coronary arteries compromising the myocardial blood flow, is recognized recently under the chapter of myocardial infarction with nonobstructive coronary arteries (MINOCA). Invasive strategies such as PCI (percutaneous coronary intervention) and CABG (coronary artery bypass graft) have shown benefits in CAS with significant atherosclerotic lesions. Long-acting nondihydropyridine calcium channel blockers are recommended for first line therapy. ![]() Different invasive and noninvasive therapeutic approaches are approved for the management of CAS. It allows to reproduce CAS and to evaluate reactivity to nitrates. Regardless of the limited benefits proffered by the newly emerged cardiac imaging modalities, the provocative test remains the cornerstone diagnostic tool for CAS. ![]() Multiple mechanisms such as the autonomic nervous system, endothelial dysfunction, chronic inflammation, oxidative stress, and smooth muscle hypercontractility are involved. A wide spectrum of clinical manifestations from silent disease to sudden cardiac death was attributed to this complex entity with unclear pathophysiology. However, the prevalence of CAS tends to decrease in correlation with the increasing use of medicines such as calcium channel blockers, angiotensin converting enzyme inhibitor, and statins, the controlling management of atherosclerotic risk factors, and the decreased habitude to perform a functional reactivity test in highly active cardiac catheterization centers. Coronary artery spasm (CAS) defined by a severe reversible diffuse or focal vasoconstriction is the most common diagnosis among INOCA (ischemia with no obstructive coronary artery disease) patients irrespective to racial, genetic, and geographic variations.
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