Recent research indicates that women may face similar or higher cardiovascular event risks compared to men despite often having lower volumes of coronary artery plaque. This phenomenon is largely attributed to women typically having smaller coronary arteries, where even modest plaque accumulation can represent a significant obstruction. Additionally, a separate study highlights an increase in in-hospital heart attack deaths among younger adults, with women experiencing higher mortality rates than men and presenting more frequently with nontraditional risk factors.
Coronary Plaque Burden and Cardiovascular Risk
A study published in "Circulation: Cardiovascular Imaging," an American Heart Association journal, investigated sex differences in coronary artery plaque burden and subsequent cardiovascular events. The research analyzed health data from 4,267 adults (average age 60, 51% women) who presented with stable chest pain and no prior history of coronary artery disease. Participants, a subset from the PROMISE trial, underwent diagnostic evaluation via coronary computed tomography angiography (CCTA) and were followed for approximately two years.
Key Findings on Plaque and Events
- Plaque Prevalence and Volume: Fewer women (55%) had coronary artery plaque compared to men (75%). Women also exhibited a lower median volume of artery plaque (78 mm³) than men (156 mm³).
- Cardiovascular Event Rates: Despite having less plaque volume, women demonstrated similar rates as men for major adverse cardiovascular events, including all-cause mortality, non-fatal heart attack, or hospitalization for chest pain (2.3% of women vs. 3.4% of men).
- Risk Thresholds: Women's heart risk began to increase at a lower plaque burden (20%) compared to men (28%). The risk also increased more sharply for women with escalating plaque levels.
- Vessel Size Adjustment:
Researchers noted that women's smaller coronary arteries mean a lower absolute plaque volume can signify a comparable or higher total plaque burden, which refers to the percentage of the vessel area occupied by fatty deposits. This provides a potential explanation for similar event rates despite differences in total plaque volume.
Non-Obstructive Coronary Artery Disease
The study also highlighted that women are more frequently diagnosed with non-obstructive coronary artery disease. Previous findings from the broader PROMISE trial indicated that most heart attacks and deaths, particularly in women, occurred in patients with non-obstructive coronary artery disease, a condition involving artery tightening, poor function in tiny vessels, or compression by heart muscle.
Expert Perspectives
Dr. Borek Foldyna, an assistant professor of radiology at Harvard Medical School and a senior author, stated that the findings suggest women are not "protected" from coronary events despite lower plaque volumes. He added that standard definitions of high risk might underestimate risk in women.
Jan Brendel, lead author and a postdoctoral research fellow at Massachusetts General Hospital, indicated that women's risk appeared to emerge at lower plaque burden levels despite having lower overall plaque volumes. Brendel suggested potential mechanisms for the observed sex differences include hormonal influences, differences in vascular biology, microvascular dysfunction, and inflammatory processes.
Dr. Stacey E. Rosen, a volunteer president of the American Heart Association, noted the importance of recognizing fundamental biological differences in how cardiovascular disease affects men and women, influencing risk factors, symptoms, and treatment response.
Cardiologist Julie Marcus, who was not involved in the study, commented that the increasing use of cardiac CT angiography and new analytics concerning plaque composition are raising questions about the implications of non-obstructive disease and are crucial for a better mechanistic understanding of sex differences in coronary artery disease.
Clinical Implications
The study's authors suggest that traditional risk models, often developed using male populations, might not fully capture the biology of atherosclerosis in women. Integrating quantitative plaque assessment into CCTA interpretation could support more precise cardiovascular risk assessment and individualized prevention strategies. Marcus proposed that thresholds for initiating medical treatments might need adjustment for women, given that their risk of adverse outcomes emerged at lower plaque burdens.
Heart Attack Mortality in Younger Adults
A separate study, published in the "Journal of the American Heart Association," analyzed nearly 1 million hospitalizations for first-time heart attacks among U.S. adults aged 18-54, using data from the National Inpatient Sample between 2011 and 2022.
Key Findings on Mortality
- Increased Deaths: In-hospital deaths from severe heart attacks (STEMI) increased by an absolute 1.2% among adults aged 18-54 during the study period, while rates for less severe heart attacks (NSTEMI) remained unchanged.
- Higher Mortality in Women: Women had higher in-hospital death rates for first-time heart attacks compared to men (3.1% for STEMI vs. 2.6% for men; 1% for NSTEMI vs. less than 1% for men).
- Procedure Disparities: Despite similar rates of in-hospital complications, women received fewer cardiovascular procedures than men.
- Risk Factors: Nontraditional risk factors, such as low income, kidney disease, and non-tobacco drug use, were more strongly associated with in-hospital heart attack deaths than traditional risk factors (e.g., high blood pressure, high cholesterol) in both sexes. Younger women were more likely to present with nontraditional risk factors compared to men of the same age.
Demographics and Risk Factors
Of the hospitalizations analyzed, approximately 40% were STEMI cases and 62% were NSTEMI cases. Men comprised 77.2% of STEMI hospitalizations and 66.2% of NSTEMI hospitalizations. Tobacco use was the most common traditional risk factor for STEMI, while high blood pressure was most common for NSTEMI. Low income was the most prevalent nontraditional risk factor for both types of heart attacks in both sexes, with a higher proportion among women for NSTEMI.
Study Implications and Limitations
The findings suggest that improving heart attack outcomes in adults younger than 55, particularly women, will require earlier risk identification and consideration of nontraditional risk factors to enhance treatment strategies. The study's limitations include its reliance on administrative hospital data, which may contain incorrect diagnoses or treatment codes, and the absence of long-term follow-up information post-hospital discharge.