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Vakhtangadze et al. Myocardial ischemia in women

Similar results have been obtained in other studies. In The difference between men and women also exists
2015, Lee et al. [15] published the results of a prospective in stable coronary syndromes. As noted above, in the
study that evaluated patients with non-obstructive CAD. WISE study, only 38% of women with a stable coronary
Overall, 77% of patients in the cohort were women; syndrome had severe obstructive CAD, and the rest
44% of all patients had endothelial dysfunction, 21% (62%) showed evidence of non-obstructive CAD. [13,14,17,20]
had microvascular impairment, and 5% had a reduced
fractional flow reserve. In 23% of cases, it was not CORONARY MICROVASCULAR DYSFUNCTION
possible to determine the cause of coronary symptoms.
This study confirmed the results of previous studies [16-18] Myocardial ischemia is usually caused by narrowing of
indicating that while the symptoms of CAD are well epicardial coronary arteries. Over the past 30 years,
understood, women tend to develop symptoms 10-15 however, many studies have revealed that impaired
years later than men, and have more risk factors by the coronary microcirculation can also lead or contribute to
time of symptom onset. The study by Lee et al. [15] did the development of ischemia of myocardial cells.
not evaluate the influence of hormonal factors on the
clinical presentation of symptoms. Most of the articles published on myocardial ischemia
have been designed to evaluate coronary obstruction
Thus, an incomplete understanding of the sex-specific and to determine strategies for the early detection of
physiology of myocardial ischemia and underdeveloped obstructive CAD. However, there is lack of research
diagnostic and treatment options may lead to the on detection of ischemia in patients with normal
inadequate management of a large proportion of the or non-obstructive coronary arteries, which mainly
population and a large number of women without signs present in women. As previously mentioned, women
of obstructive CAD at coronary angiography presenting are less likely than men to undergo diagnostic or
with symptom-related disability. All of this consumes a preventive measures. Since the 1980s, the information
considerable amount of healthcare resources. [6] about microvascular disease has expanded. In 2007,
Camici and Crea [23] evaluated clinical settings in
A European study published in 2012 found that angina which myocardial ischemia occurs and proposed a
in patients with normal blood vessels or non-obstructive classification of coronary microvascular dysfunction
atherosclerosis was associated with an increased risk (CMVD) based on the underlying diseases in which
of the combined endpoint of cardiovascular death, it occurs (e.g. obstructive CAD, cardiomyopathy, and
hospitalization due to myocardial infarction, heart systemic diseases). Their classification is as follows:
failure, or stroke of up to 52% in the case of patients • Class 1: CMVD in the absence of obstructive
with normal coronary arteries and 85% in those with CAD and myocardial diseases.
non-obstructive coronary atherosclerosis. In addition, • Class 2: CMVD in the presence of myocardial
these patients had an increased risk of all-cause diseases.
mortality of up to 29% and 52%, respectively, with • Class 3: CMVD in the presence of obstructive
no differences between men and women. [19] Such CAD.
physiological patterns have also been reported in other • Class 4: CMVD caused by coronary recana-
studies evaluating invasive and non-invasive coronary lization (i.e. iatrogenic).
flow reserve. [20,21] All of these findings demonstrate the
importance of evaluating and managing women with In an everyday setting, it is very difficult to distinguish
non-obstructive CAD. the forms of CMVD because small coronary arteries
cannot be visualized by angiography. During invasive
Morphological studies have shown that the development investigations, complex, time-consuming, and costly
of myocardial infarction is based on plaque rupture, methods are required to carefully assess the function
plaque ulceration, and plaque calcification. [22] Plaque of the coronary microcirculation. In patients suspected
erosion/ulceration is another pathophysiological of having microvascular angina, accepted hallmarks
mechanism of myocardial infarction. In this case, of myocardial ischemia, such as stress-induced left
damage of the integrity of the plaque cap leads to ventricular contractile alterations, [23-26] are usually
the development of a thrombus, with emboli from the undetectable. A sparse distribution of myocardial
plaque travelling to areas distal to the plaque and ischemia in a patient presenting with CMVD is,
eventually blocking the lumen of the vessel. In most on one hand, sufficient to produce ECG changes
cases, this mechanism underlies the development of and myocardial perfusion defects on single-photon
myocardial infarcts in women, and this type of non- emission computed tomography (SPECT); but, on the
obstructive atherosclerosis of coronary arteries is other hand, might not result in detectable contractile
found more commonly in women with myocardial abnormalities because of normal function of the
infarction than in men. [14,17,20-22] surrounding myocardial tissue. [26,27]

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