Coronary Microvascular Dysfunction May Predict Heart Disease in Rheumatoid Arthritis

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Cardiovascular disease (CVD) is a leading cause of death in patients with rheumatoid arthritis (RA). Patients with RA have a 1.5 times increased risk for heart attack compared with the general population.

Although the treatment of RA has advanced significantly, the ability to prevent cardiovascular events hasn’t followed. A study in Arthritis Care & Research suggests coronary microvascular dysfunction may be a predictor of heart disease in this population, as has been shown in people with diabetes and the general population. Researchers have not yet been able to pinpoint what clinicians should measure to capture excess cardiovascular risk among patients with RA.¹

Higher Risk of Mortality

“When we think about CVD we usually focus on coronary arteries and cholesterol,” says lead author Katherine Liao, MD, MPH, associate professor of medicine at Harvard Medical School, Boston. “Researchers have found that in both diabetes and the general population, dysfunction of the smaller vessels in the heart, known as the coronary micro­vasculature, leads to a higher risk for cardiac mortality.”

The researchers compared RA patients with those who have diabetes, a group of patients in whom coronary microvascular dysfunction is an established cause of cardiac mortality. They looked at whether microvascular dysfunction in the heart exists in patients with RA. If so, is it tied to cardiac and all-cause mortality?

Study Parameters

Dr. Liao

The researchers undertook a retrospective cohort study using data obtained from all patients undergoing stress myocardial perfusion positron emission tomography (PET) scans between 2006 and 2017 at Brigham and Women’s Hospital, Boston.

All patients with a normal stress test were included in the study. Patients with known coronary artery disease, a history of myocardial infarction, coronary revascularization, transplantation or moderate to severe valve disease were excluded. Others not included were those with abnormal PET scans showing they already had obstructive coronary artery disease.

Pertinent patient information, such as biologic and non-biologic disease-modifying anti-rheumatic drug use, was obtained through medical records. Data on diabetes treatments, other traditional CVD risk factors, as well as medications used for primary and secondary CVD prevention, were also added. Coronary flow reserve (CFR; the ability of the coronaries to increase blood flow under stress) was calculated using the registry. Coronary microvascular dysfunction was defined as CFR <2.0.

“The data we use to calculate CFR and detect [coronary microvascular dysfunction] are, in many cases, obtained routinely as part of the cardiac stress test,” says Dr. Liao. “Since the main reason to undergo a stress test is to look for blockages in the coronary arteries and not microvascular function, we are not routinely pulling data on [coronary microvascular dysfunction].”

The cohort included 73 subjects with RA and 441 with diabetes who met the inclusion or exclusion criteria. The mean age was similar in both groups: 63 years. The proportion of women was higher in RA than in diabetes (73% vs. 56%, respectively). Those with diabetes had higher prevalence of hypertension and dyslipidemia. Eighteen percent had concurrent RA and diabetes.