variant angina

異型狭心症

WordNet

1. exhibiting variation and change; "letters variant in size"
2. differing from a norm or standard; "a variant spelling"
3. any disease of the throat or fauces marked by spasmodic attacks of intense suffocative pain

PrepTutorEJDIC

1. (同種のものと)異なった,別の / 異形;(同じ単語の)異なったつづり(発音など)
2. アンギナ(のどの炎症に関する諸病気) / =angina pectoris

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2017/06/19 19:52:44」(JST)

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Prinzmetal angina
Classification and external resources
Specialty	cardiology
ICD-10	I20.1
ICD-9-CM	413.1
DiseasesDB	13727
MedlinePlus	000159
eMedicine	med/447
MeSH	D000788

Prinzmetal's or Prinzmetal angina (/ˈprɪntsmɛtəl/, sounds like "prints metal") (also known as variant angina, vasospastic angina (VSA), angina inversa, or coronary vessel spasm) is a syndrome typically consisting of angina (cardiac chest pain) at rest that occurs in cycles. It is caused by vasospasm, a narrowing of the coronary arteries caused by contraction of the smooth muscle tissue in the vessel walls rather than directly by atherosclerosis (buildup of fatty plaque and hardening of the arteries).

For a portion of patients Prinzmetal's angina may be a manifestation of vasospastic disorder and is associated with migraine, Raynaud's phenomenon or aspirin-induced asthma.

Signs and symptoms

In contrast to patient with unstable angina secondary to coronary atherosclerosis, patients with variant angina are generally younger and have fewer coronary risk factors (except smoking). Episode of chest pain usually does not progress from a period of chronic stable angina. Cardiac examination is usually normal in the absence of ischemia.

Symptoms typically occur at rest, rather than on exertion (thus attacks usually occur in early morning hours). Two-thirds of patients have concurrent atherosclerosis of a major coronary artery, but this is often mild or not in proportion to the degree of symptoms.

Prinzmetal's should be suspected by a cardiologist when the pain occurs at rest and/or in clusters, and in the absence of a positive treadmill stress test, as Prinzmetal's is exercise tolerant and can generally only be diagnosed after other forms of cardiac disease have been ruled out.

It is associated with specific ECG changes (elevation rather than depression of the ST segment) together with small elevation of cardiac enzymes (especially with long attacks). However, in order to be diagnosed, these ECG changes can only be tracked when the electrocardiogram occurs while the patient is experiencing an attack. Therefore, many experts recommend provocative testing during electrocardiogram testing to attempt to induce an attack when Prinzmetal's is suspected.

Mechanism

The mechanism that causes such intense vasospasm, as to cause a clinically significant narrowing of the coronary arteries is so far unknown, but there are three relevant hypotheses:

1. Enhanced contractility of coronary vascular smooth muscle due to reduced nitric oxide bioavailability caused by a defect in the endothelial nitric oxide synthetase enzyme which leads to endothelial function abnormalities.
   • Acetylcholine is normally released by the parasympathetic nervous system (PSNS) at rest, and causes dilation of the coronary arteries. While acetylcholine induces vasoconstriction of vascular smooth muscle cells through a direct mechanism, acetylcholine also stimulates endothelial cells to produce nitric oxide (NO). NO then diffuses out of the endothelial cells, stimulating relaxation of the nearby smooth muscle cells. In healthy arterial walls, the overall indirect relaxation induced by acetylcholine (via nitric oxide) is of greater effect than any contraction that is induced.
   • When the endothelium is dysfunctional, stimulation with acetylcholine will fail to produce, or produce very little, nitric oxide. Thus, acetylcholine released by the PSNS at rest will simply cause contraction of the vascular smooth muscle.
2. Thromboxane A2, a vasoconstrictor released by platelets to aid in clot formation, may also play a role in Prinzmetal's angina. Lipoprotein(a) interferes with fibrinolysis by competing with plasminogen. The impaired fibrinolysis triggers thrombus formation, which also results in coronary vasospasm in variant angina.
3. Increased alpha-adrenergic receptor activity on epicardial coronary arteries leads to coronary vasospasm.

Apart from the hypotheses mentioned above; hypercontractility of vascular smooth muscle is also thought to be associated with vasoconstrictor mitogens and serotonin.

Diagnosis

Although Prinzmetal's angina has been documented in between 2% to 10% of angina patients, it can be overlooked by cardiologists who stop testing protocol after ruling out typical angina. Rarely, an ECG can capture diffuse ST elevations.

Prinzmetal angina

Patients who develop cardiac chest pain are generally treated empirically as an "acute coronary syndrome", and are generally tested for cardiac enzymes such as creatine kinase isoenzymes or troponin I or T. These may or may not show a degree of positivity, as coronary spasm too can cause myocardial damage or may leave the arteries undamaged. Echocardiography or thallium scintigraphy is often performed.

The gold standard is coronary angiography with injection of provocative agents into the coronary artery. Rarely, an active spasm can be documented angiographically (e.g. if the patient receives an angiogram with intent of performing a primary coronary intervention with angioplasty). Depending on the local protocol, provocation testing may involve substances such as ergonovine, methylergonovine or acetylcholine and hyperventilation. Exaggerated spasm is diagnostic of Prinzmetal angina.

Treatment

Prinzmetal's angina typically responds to nitrates and calcium channel blockers.

Use of a beta blocker such as propranolol is contraindicated in Prinzmetal's angina. Prazosin has also been found to be of value in some patients. Coronary revascularization is only useful when the patient shows concomitant coronary atherosclerosis on coronary angiogram.

Eponym

It was described as "A variant form of angina pectoris" in 1959 by the American cardiologist Myron Prinzmetal (1908–1987). However, it had been described twice in the 1930s by other authors.

It was first referred to as cardiac syndrome X (CSX) by Kemp in 1973, to describe patients with exercise-induced angina and normal coronary angiograms.

See also

• Kounis syndrome

External links

• Prinzmetal's angina at Who Named It?
• Coronary artery spasm at the Heart Foundation
• Crea, F; Lanza, GA. "Vasospastic Angina". European Society of Cardiology. 
• www.prinzmetal.dk A site about Prinzmetal variant angina and cardiac syndrome x
• APAA - American Prinzmetal's Angina Association A site that gathers and shows both information for the public and also technical information for medical practitioners.

UpToDate Contents

全文を閲覧するには購読必要です。 To read the full text you will need to subscribe.

• 1. 異型狭心症 variant angina
• 2. 心臓症候群X：正常冠動脈の狭心症 cardiac syndrome x angina pectoris with normal coronary arteries
• 3. 成人における胸痛の鑑別診断 differential diagnosis of chest pain in adults
• 4. Myocardial infarction with no obstructive coronary atherosclerosis
• 5. 急性冠症候群がない患者にでの心筋トロポニン濃度の上昇 elevated cardiac troponin concentration in the absence of an acute coronary syndrome

English Journal

• Chest pain in patients with 'normal angiography': could it be cardiac?

• Di Fiore DP, Beltrame JF.SourceThe Queen Elizabeth Hospital, Discipline of Medicine, The University of Adelaide, Woodville South, South Australia, Australia.
• International journal of evidence-based healthcare.Int J Evid Based Healthc.2013 Mar;11(1):56-68. doi: 10.1111/1744-1609.12002.
• Approximately 20% of patients undergoing diagnostic angiography for the evaluation of chest pain are found to have a normal coronary angiogram. Although this finding is generally associated with a low risk of cardiac events, approximately half will continue to experience chest pain over the next 12
• PMID 23448331

• Eosinophilic coronary periarteritis (vasospastic angina and sudden death), a new type of coronary arteritis: report of seven autopsy cases and a review of the literature.

• Kajihara H, Tachiyama Y, Hirose T, Takata A, Saito K, Murai T, Yasui W.SourceDivision of Tumor Registry, Hiroshima Prefectural Medical Association, Kannon-honmachi1-1-1, Nishi-Ku, Hiroshima 733-8540, Japan. kajihara@sky.megaegg.ne.jp
• Virchows Archiv : an international journal of pathology.Virchows Arch.2013 Feb;462(2):239-48. doi: 10.1007/s00428-012-1351-7. Epub 2012 Dec 12.
• A previously reported autopsy case of eosinophilic coronary periarteritis (ECPA, or isolated eosinophilic coronary periarteritis, IECPA), and an additional six autopsy cases of ECPA are reported. In addition, another four autopsy cases of ECPA reported in the literature are discussed. Fifteen cases
• PMID 23232800

Japanese Journal

• ステロイドが著効した難治性異型狭心症を合併したAspirin-exacerbated respiratory disease（AERD）の1例

• アレルギー 65(2), 123-127, 2016
• NAID 130005145463

• The Who, What, Why, When, How and Where of Vasospastic Angina

• Circulation Journal 80(2), 289-298, 2016
• NAID 130005120904

• The Who, What, Why, When, How and Where of Vasospastic Angina

• Circulation Journal advpub(0), 2015
• NAID 130005114511

Related Links

• Variant angina - Evidence-Based Clinical Decision Support at ...

Variant angina, which is also referred to as Prinzmetal or vasospastic angina, is a clinical entity characterized by episodes of angina pectoris, usually at rest and often between midnight and early morning, in association with ST ...

• Prinzmetal's or Prinzmetal Angina, Variant Angina and Angina ...

The American Heart Association explains Prinzmetal?s angina, which always occurs when a person is at rest, usually between midnight and early morning. ... Unlike typical angina – which is often triggered by exertion or emotional ...

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