Noninvasive imaging tools to detect stable ischemic heart disease in women

In the current issue of Cardiovascular Innovations and Applications (Special Issue on Women's Cardiovascular Health, Volume 3, Number 4, 2019, Guest Editor Gladys P. Velarde) pp. 375-389(15); DOI: https://doi.org/10.15212/CVIA.2019.0007 Viviany R. Taqueti from the Cardiovascular Imaging Program, Heart and Vascular Center, Division of Cardiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA reviews novel imaging approaches for the diagnosis of stable ischemic heart disease in women.

This article provides a valuable provocative insight into the importance of advanced noninvasive imaging tools like CCTA, PET, and CMR in enabling very sensitive assessments of anatomic atherosclerotic plaque burden, macro and micro-vessel related ischemia, and myocardial fibrosis respectively. The author emphasizes the importance of low coronary flow reserve (CFR) as a potential link to understanding the hidden biological risk of stable IHD among women where abnormal coronary reactivity often co-exists with diffuse, nonobstructive CAD, a phenotype more prevalent in women and less amenable to focal revascularization. The author explains how the pathophysiology of obstructive and nonobstructive coronary disease renders itself to a more accurate diagnosis with the appropriate utilization of these novel modalities.

Conventional recommendations for diagnostic testing for the evaluation of stable ischemic heart disease in women have largely paralleled those in men. Although they are designed primarily for the identification of obstructive coronary artery disease (CAD), traditional approaches can lead to overtesting in women without differentiating who is truly at risk. Several unique factors related to the presentation, diagnosis, and underlying pathophysiology of stable ischemic heart disease in women necessitate a more specific approach to the assessment of their risk, complete with separate guidelines when appropriate. This article highlights how advanced noninvasive imaging tools, including cardiac computed tomography angiography, positron emission tomography, and cardiac magnetic resonance imaging, are enabling very sensitive assessments of anatomic atherosclerotic plaque burden, macrovessel- and microvessel-related ischemia, and myocardial fibrosis, respectively. Moving forward, effective diagnostic testing will need to identify women at high risk of adverse cardiovascular events (not anatomically obstructive CAD per se) without overtesting those at low risk. Judicious application of novel imaging approaches will be critical to broadening the definitions of CAD and ischemia to better reflect the whole spectrum of pathological phenotypes in women, including nonobstructive CAD and coronary microvascular dysfunction, and aid in the development of needed evidence-based strategies for their management.

This article forms part of a special issue on Women's Cardiovascular Health, guest edited by Gladys P. Velarde. Recent decades have witnessed great progress in the treatment of cardiovascular disease (CVD). Due to improved therapies, preventive strategies and increased public awareness, CVD (stroke, heart failure, ischemic heart disease, peripheral arterial disease and congenital heart disease) mortality has been on the decline over this span of time for both genders. Unfortunately, the decline has been less prominent for women, especially women of color. Once viewed as a man's disease, CVD remains the leading cause of mortality for women in the United States and is responsible for a third of all deaths of women worldwide and half of all deaths of women over 50 years of age in developing countries. In the United States, CVD far outpaces all other causes of death, including all forms of cancer combined. The statistics are sobering with about one female death in the United States every 80 seconds from CVD. That represents close to 400,000 deaths per year according to the more recent statistics. Of these, more than one quarter of a million women will die this year from ischemic heart disease (IHD) which includes obstructive and non-obstructive coronary disease, and about 64% of women who die suddenly of IHD have no prior symptoms. Despite a significant number of females with known CVD and increased awareness among women of heart disease as their major health threat, a substantial proportion of women (46% as per the most recent American Heart Association survey) remain unaware of their cardiovascular risk and continue to fail to recognize its significance.

This lack of awareness is more profound (over 60% unaware) among women in higher-risk groups, racial and ethnic minorities, and has changed little in decades.

Poorly understood sex/gender differences in pathobiologic mechanisms, clinical presentation, management and application of diagnostic and therapeutic and preventive strategies have contributed to this gap. A critically important factor has been the underrepresentation of women in CVD research to date. In fact, only one-third of CVD clinical trials report sex-specific results despite The Food and Drug Administration regulations requiring sex stratification data, as well as the National Institute of Health recommendations of increased inclusion of women in clinical trials. This makes it difficult for researchers and clinicians to draw accurate conclusions about sex differences in mechanisms of disease, accuracy of specific diagnostic modalities and risks or benefits of a particular drug or device for the treatment of women with CVD. Furthermore, physicians and other healthcare providers continue to underestimate women's cardiovascular risk, in part because of utilization of traditional approaches which can lead to over-testing or inappropriate risk assessment without accurate differentiating who is truly at risk and inadequate use of preventive therapies for women.

The goal of this special edition Cardiovascular Innovations and Applications is to shed some light on specific topics that dominate the spectrum of CVD in women.