Coronary microvascular dysfunction in women: an overview of diagnostic strategies

Abstract

Coronary microvascular dysfunction (CMD) also known as syndrome X, is characterized by typical anginal symptoms, evidence of myocardial ischemia on non-invasive testing and normal to minimal coronary disease on coronary angiography. It has a female preponderance and has been detected in up to 50% of women presenting with chest pain symptoms. Definitive diagnosis of CMD is critical as recent evidence suggests that women with this condition are at increased risk of cardiovascular events in the future. Invasive coronary reactivity testing on coronary angiography is considered to be the ‘gold standard’ for diagnosis of CMD. Non-invasive imaging techniques such as PET and cardiac magnetic resonance hold promise for detection of CMD in the future.

Keywords::

• cardiac magnetic resonance
• coronary microvascular dysfunction
• diagnosis
• myocardial perfusion reserve

Financial & competing interests disclosure

C Kramer receives research equipment support from Siemens Healthcare and is a consultant for Synarc. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

No writing assistance was utilized in the production of this manuscript.

Key issues

• • Coronary microvascular dysfunction (CMD), also known as syndrome X, is characterized by typical anginal symptoms, evidence of myocardial ischemia on non-invasive testing and normal to minimal coronary disease on coronary angiography.

• • It is seen commonly in women, with studies showing that up to 50% of women presenting with anginal symptoms have CMD.

• • Several pathophysiological mechanisms have been proposed to explain the microvascular dysfunction that occurs in the coronary vascular system.

• • Diagnosis of CMD involves demonstration of microvascular dysfunction either invasively or noninvasively.

• • Invasive testing of CMD is the current gold standard for diagnosis and involves the use of quantitative coronary angiography to evaluate changes in coronary vessel wall diameter in response to vasodilators such as adenosine and acetylcholine.

• • The current definition for CMD requires <2.5-fold increase in coronary volumetric blood flow on intracoronary angiography in response to adenosine.

• • PET imaging is an established method to detect CMD and a coronary flow reserve of <2.5 has been shown in studies to be diagnostic of CMD.

• • Stress CMR is also a newer imaging method that holds considerable promise for the effective diagnosis of CMD.

• • Current evidence suggests that the diagnosis of CMD is not benign and is associated with worsening cardiovascular risk. Larger studies are needed to further validate this finding.