Microvascular angina
Cardiac syndrome X is a historic term for microvascular angina.
SeeCoronary microvascular dysfunction causing cardiac ischemia in women
Refers to,angina with signs associated with decreased blood flow to heart tissue but with normal coronary arteries.
An increased risk of other vasospastic disorders in cardiac microvascular angina patients, include migraine and Raynaud’s phenomenon.
It is treated with beta-blockers.
Beta blockers can make coronary spasms worse.
It is adistinct diagnosis from Prinzmetal’s angina.
Microvascular angina entails all of the following:
Angina that usually does not cause dysfunction on echocardiogram,
Angina that can last longer than that of heart disease:pain associated with microvascular angina is normally more intense and it lasts for longer periods of time compared to pain caused by other conditions.
Abnormal cardiac stress test: ST changes are typically similar to those of coronary artery disease, and the opposite of those of Prinzmetal’s angina.
Chest pain caused by microvascular angina is most of the time unpredictable and it can occur when at rest and/or during exercise.
Myocardial perfusion imaging can be abnormal in 30% of patients.
Coronary angiogram: Normal
Other causes of chest pain must be ruled out, including: vasospastic or variant angina / Coronary artery spasm.
Esophageal spasm
Narrowing of the artery due to plaque formation.
No specific known cause for microvascular angina exists: it is
rather a multitude of risk factors that act together.
Microvascular angina is believed to be caused by the lack of blood flow caused by a microvascular disease and enhanced pain perception.
The microvascular dysfunctions occur in the very small blood vessels of the heart.
Blood vessel narrowing may lead to lack of oxygen in specific areas of the cardiac muscle causing chest pain.
Patients living with microvascular angina may have an enhanced pain perception, than individuals without microvascular angina .
Risk factors: abdominal obesity, dyslipidemia, elevated blood pressure, insulin resistance or intolerance to glucose, prothrombotic state or proinflammatory state.
Older people are more at risk.
Some evidence exists suggesting genetic mutations predisposition.
Women are more prone to this condition than men.
Women with a history of heart disease in the family are prone.
Microvascular angina is a diagnosis of exclusion.
Diagnosis requires: clinical consistency, appropriate stress testing, and a coronary angiogram that meet the above criteria.
Cardiac MRI can be used to diagnose microvascular angina.
It is caused by a functional disorder of the microvessels.
Coronary microvascular dysfunction: Blood vessels either fail to dilate or constrict in response to stressors such as exercise, the cold or emotional stress.
Microvascular dysfunction can be demonstrated by angiogram with acetylcholine which can affect the microvessels and larger coronary arteries leading to either microvascular angina or coronary artery spasms.
Mitroglycerin is not effective in most patients with microvascular angina.
Management:
calcium channel blockers – specifically nifedipine and diltiazem can be effective.
beta blockers, work, but can make coronary spasms worse.
aminophylline by inhibiting adenosine receptors.
estrogen may work in women.
L-Arginine – increases release of NO at vascular level, thus leading to vasodilatory effect
Ranolazine – shown to improve angina and myocardial ischemia
Statins
Aspirin
Clopidogrel
ACE inhibitors and ARBs
Lifestyle changes such as diet and exercise.
Microvascular angina is a chronic long term condition which increases the risk of cardiac events such as heart failure and frequent hospital admissions.
Treatment consists of drugs, mainly to relieve chest pain.
The first step is the administration of nitrates which may relieve the chest pain.
Nitrates relax the muscles of the heart and blood vessels, but are inefficient in as many as half of patients.
Alternative treatments may consist of calcium channel blockers or beta blockers which reduce chest pain by relaxing the muscle cells lining the artery and improving blood flow to the heart while lowering blood pressure.
The combination of nonnitrate vasodilators, such as calcium channel blockers and angiotensin converting enzyme (ACE) inhibitors along with statins effective in many women.
Ranolazine and Ivabradine, promising agents in microvascular angina.
Estrogen can be effective in women.
A change in lifestyle is important.