Unstable angina / non ST elevation myocardial infarction cardiovascular syndrome x


 * Associate Editor-In-Chief: Smita Kohli, M.D.

Overview of Cardiovascular Syndrome X in UA / NSTEMI

 * Cardiovascular syndrome X refers to patients with angina or angina-like discomfort with exercise, ST-segment depression on exercise testing, and normal or nonobstructed coronary arteries on angiography.
 * This entity should be differentiated from the metabolic syndrome X or metabolic syndrome, which describes patients with insulin resistance, hyperinsulinemia, dyslipidemia, hypertension, and abdominal obesity.
 * It also should be differentiated from noncardiac chest pain.


 * Syndrome X is more common in women than in men.
 * The cause of the discomfort and ST-segment depression in patients with syndrome X is not well understood. The most frequently proposed causes are:
 * impaired endothelium dependent arterial vasodilatation with decreased nitric oxide production,
 * impaired microvascular dilation (non–endothelium-dependent),
 * increased sensitivity to sympathetic stimulation, or
 * coronary vasoconstriction in response to exercise.


 * Recently, there is increasing evidence that these patients frequently also have an increased responsiveness to pain and an abnormality in pain perception.

Diagnosis

 * The diagnosis of syndrome X is suggested by the triad of:
 * anginal-type chest discomfort,
 * objective evidence of ischemia, and
 * absence of obstructive CAD.


 * This can be confirmed by provocative coronary angiographic testing with acetylcholine for coronary endothelium-dependent function and adenosine for non–endothelium-dependent microvascular function.
 * Other non-cardiac causes of chest pain,such as esophageal dysmotility, fibromyalgia, and costochondritis, should be ruled out.

Treatment

 * It is recommended that patients be reassured of the excellent intermediate-term prognosis and treated with long-acting nitrates.


 * If the patient continues to have episodes of chest pain, a calcium channel blocker or beta blocker can be started.


 * Beta blockers and calcium channel blockers have been found to be effective in reducing the number of episodes of chest discomfort. Nitrates can be helful in half of the patients.


 * Imipramine 50 mg daily has been successful in some chronic pain syndromes, including syndrome X, reducing the frequency of chest pain by 50%.


 * Transcutaneous electrical nerve stimulation and spinal cord stimulation can offer good pain control.


 * Statin therapy and exercise training have improved exercise capacity, endothelial function, and symptoms in some studies.

==ACC / AHA Guidelines (DO NOT EDIT) == {{cquote|

Class I
1. Medical therapy with nitrates, beta blockers, and calcium channel blockers, alone or in combination is recommended in patients with cardiovascular syndrome X. (Level of Evidence: B)

2. Risk factor reduction is recommended in patients with cardiovascular syndrome X. (Level of Evidence: B)

Class IIb
1.Intracoronary ultrasound to assess the extent of atherosclerosis and rule out missed obstructive lesions may be considered in patients with syndrome X. (Level of Evidence: B)

2. If no ECGs during chest pain are available and coronary spasm cannot be ruled out, coronary angiography and provocative testing with acetylcholine, adenosine, or methacholine and 24 h ambulatory ECG may be considered. (Level of Evidence: C)

3. If coronary angiography is performed and does not reveal a cause of chest discomfort, and if syndrome X is suspected, invasive physiological assessment (i.e., coronary flow reserve measurement) may be considered. (Level of Evidence: C)

4.Imipramine or aminophylline may be considered in patients with syndrome X for continued pain despite implementation of Class I measures. (Level of Evidence: C)

5. Transcutaneous electrical nerve stimulation and spinal cord stimulation for continued pain despite the implementation of Class I measures may be considered for patients with syndrome X. (Level of Evidence: B)

Class III
1. Medical therapy with nitrates, beta blockers, and calcium channel blockers for patients with non cardiac chest pain is not recommended. (Level of Evidence: C)}}