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Published on: August 17, 2022
Coronary microvascular dysfunction is associated with cardiac time intervals in women with angina and no obstructive
Adam Pena1,2, Marie Mide Michelsen1, Naja Dam Mygind3
1Department of Cardiology, Bispebjerg University Hospital, Copenhagen, Denmark.
Insights
Coronary microvascular dysfunction (CMD) in women with angina is linked to longer isovolumic contraction time (IVCT) and higher myocardial performance index (MPI). These cardiac time intervals may help diagnose CMD without invasive procedures.
Area of Science:
- Cardiology
- Echocardiography
- Vascular Biology
Background:
- Coronary microvascular dysfunction (CMD) can cause angina without obstructive coronary artery disease (CAD), increasing cardiovascular event risk.
- Transthoracic Doppler echocardiography (TTDE) assesses coronary flow velocity reserve (CFVR) for microvascular function, but simpler diagnostic methods are needed.
- This study investigates the relationship between CFVR and cardiac time intervals (CTIs) measured by TTDE in women with angina and no obstructive CAD.
Purpose of the Study:
- To determine if cardiac time intervals measured by TTDE can serve as simpler indicators of coronary microvascular dysfunction (CMD) in women with angina and no obstructive CAD.
- To explore the association between coronary flow velocity reserve (CFVR) and specific CTIs, including isovolumic contraction time (IVCT), ejection time (ET), and isovolumic relaxation time (IVRT).
- To identify potential echocardiographic markers for diagnosing CMD in a relevant patient population.
Main Methods:
- A prospective cohort study included 389 women with angina, preserved ejection fraction (>45%), and no obstructive CAD.
- Coronary microvascular dysfunction (CMD) was defined by a coronary flow velocity reserve (CFVR) < 2.0.
- Cardiac time intervals (IVCT, ET, IVRT) and myocardial performance index (MPI) were measured using TTDE; patients were grouped by CFVR values.
Main Results:
- Coronary microvascular dysfunction (CMD) was associated with older age, hypertension, higher resting heart rate, and lower diastolic blood pressure.
- CMD correlated with a higher E/e' ratio, longer IVCT, higher MPI, and shorter ET.
- In multivariable analysis, longer IVCT (P < 0.001) and higher MPI (P = 0.002) remained significantly associated with CMD.
Conclusions:
- In women experiencing angina without obstructive CAD, CMD is associated with prolonged IVCT and elevated MPI.
- These findings suggest a link between CMD and subtle alterations in systolic and combined cardiac time intervals.
- Cardiac time intervals derived from TTDE may offer a non-invasive approach to assess for CMD in this patient group.
Background:
Coronary microvascular dysfunction (CMD) may cause angina in the absence of obstructive coronary artery disease (CAD) and increases the risk of future adverse cardiovascular events. Transthoracic Doppler echocardiography (TTDE) with pharmacological stress can assess coronary flow velocity reserve (CFVR), a measure of coronary microvascular function. However, simpler methods would be preferable for diagnosing CMD. Therefore, we examined the relationship between CFVR and cardiac time intervals measured by TTDE in a cohort of women with angina and no obstructive CAD.
Methods:
In a prospective cohort study, we included 389 women with angina, left ventricular ejection fraction > 45%, and no obstructive CAD. CMD was defined as CFVR < 2.0. The study population was divided into three groups according to cutoff values of CFVR < 2, 2 ≤ CFVR ≤ 2.5, and CFVR > 2.5. Isovolumic contraction time (IVCT), ejection time (ET), and isovolumic relaxation time (IVRT) were measured by tissue Doppler M-mode, and the myocardial performance index (MPI = (IVCT + IVRT)/ET) was calculated.
Results:
Coronary microvascular dysfunction was associated with increasing age, hypertension, higher resting heart rate, and lower diastolic blood pressure. Moreover, CMD was associated with higher E/e' ratio (P = 0.002) and longer IVCT (P < 0.001), higher MPI (P < 0.001) and shorter ET (P = 0.002), but not with IVRT or conventional measures of left ventricular geometry, mass, and function. In multivariable analysis, longer IVCT (P < 0.001) and higher MPI (P = 0.002) remained associated with CMD.
Conclusion:
In women with angina and no obstructive CAD, CMD is associated with longer IVCT and higher MPI indicating a link between CMD and subtle alternations of systolic and combined measures of cardiac time intervals.
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