Women may have less pericardial fat volume than men, but excess pericardial fat is associated with a higher risk of heart failure in women than in men, a new study suggests. Researchers used cardiac computed tomography to assess pericardial fat in 3,584 women and 3,201 men without preexisting cardiovascular disease. After 90,686 person-years of follow-up, 385 participants (5.7%, 164 women and 221 men) were newly diagnosed with heart failure. Overall, mean pericardial fat volume was lower in women (69 cm3) than in men (92 cm3). Each one standard deviation increase in mean pericardial fat volume (PFV) was associated with a significantly increased risk of newly diagnosed heart failure in both women (hazard ratio 1.44) and men (HR 1.13). "The association between pericardial fat and newly diagnosed heart failure is above and beyond that imposed by other indices of obesity such as body-mass index, waist circumference, hip circumference, or waist-to-hip ratio," said lead study author Dr. Satish Kenchaiah, an associate professor in cardiology at the Icahn School of Medicine at Mount Sinai and a noninvasive cardiologist at Mount Sinai Health System in New York City. The effect of pericardial fat on the risk of heart failure was similar in lean, overweight, and obese participants, Dr. Kenchaiah said by email. Similarly, the effect of pericardial fat on the risk of heart failure remained significant even after accounting for abdominal and visceral fat. High pericardial fat volume (at least 70 cm3 in women or 120 cm3 in men) was associated with a doubled risk of heart failure for women (HR 2.06) and a 53% risk increase for men (HR 1.53). When researchers examined subtypes of heart failure, they found that pericardial fat volume was primarily associated with development of heart failure with preserved ejection fraction. Associations with heart failure with reduced ejection fraction were not statistically significant. But each one-standard deviation increase in mean PFV was significantly associated with heart failure with preserved ejection fraction (HR 1.42), and high pericardial fat volume was also significantly associated with heart failure with preserved ejection fraction (HR 2.32) compared to normal PFV. It's not clear, however, whether pericardial fat volume might be a risk marker for heart failure, or also a mediator, said Dr. Barry Borlaug, MD, a professor of medicine at the Mayo Clinic in Rochester, Minnesota, who wasn't involved in the study. "If it is a risk marker, then we could potentially use an increase in pericardial fat to identify patients at high risk, so that we could treat them to prevent the development of heart failure with preserved ejection fraction," Dr. Borlaug said by email. "If it is also a mediator, then pericardial fat itself might be targeted to reduce the risk of heart failure with preserved ejection fraction." One limitation of the study is that researchers only measured pericardial fat volume in the region of the heart around the proximal coronary arteries, rather than assessing the entire heart, the study team notes. Another limitation is that researchers were unable to do a separate analysis of epicardial and paracardial fat. Additional studies are also needed to validate the cutoff for high pericardial fat volume in women and men that was used in the study, the authors note. Even so, results of this and similar studies may help clinicians stratify their patients by risk of cardiovascular diseases and subsequent heart failure, said Donatas Austys, an assistant professor of public health at Vilnius University in Lithuania. "Stratification may help in selection of strategies to lower the risk," Austys, who wasn't involved in the study, said by email. "If measurement of deposits of cardiac fat was performed in a routine fashion, this study would bring us information of what volume of pericardial adipose tissue should be treated as normal and what volume should be treated as high - very important when we aim to select patients for intervention." —Lisa Rapaport Source
