Coronary Microvascular Dysfunction May Predict Heart Disease in Rheumatoid Arthritis

Significant Survival Differences

Dr. McFarlane

Among those normal perfusion scans, the prevalence of coronary microvascular dysfunction was similar in both groups (P=0.2). However, significant differences were seen in survival when stratified by CFR <2, when compared with those ≥CFR 2. Each group of patients with CFR <2 had higher mortality rates (P<0.0001).

Coronary microvascular dysfunction was associated with increased risk for all-cause mortality in RA (HR 2.4, 95% confidence interval [CI] 1.4, 4.2). Increased cardiac-related death rates were similar to diabetes.

The group assessed increases in risk for all-cause mortality. In both RA and diabetes, having a low CFR was associated with risk for all-cause mortality after adjusting for age, gender and CV risk factors (HR 2.4, 95% CI 1.4, 4.2). None of the other measured covariates, tested individually in the base model, changed the HR by >5%.

“We know in diabetes that microvascular dysfunction leads to excess mortality,” says Dr. Liao. “We found in RA that patients in our population with cardiac microvascular dysfunction had the same degree of dysfunction and the same all-cause and cardiac mortality as those with diabetes.”

No significant changes in associations between CFR and mortality were found when the model was further adjusted to account for statin use, body mass index and prednisone use at baseline (HR 2.33, 95% CI 1.36, 3.98). Sensitivity analysis excluding patients with concurrent RA and diabetes diagnoses saw a similar relationship between CFR <2 and mortality (HR 2.47, 95% CI 1.48, 4.47)

Consider Inflammation

Dr. Liao notes that although we know inflammation is associated with increased cardiovascular risk in RA, more work is needed to define the mechanisms linking the two. This study’s results suggest a mechanism or pathway whereby inflammation leads to dysfunction in the small cardiac vessels, and this dysfunction over time is associated with increased mortality. The impact of repeated inflammation on the small vessels in the heart is something clinicians should be thinking about when considering heart disease risk in their RA patients and potential RA treatment options to control inflammation.

“Right now we use general population-based calculators, such as Framingham, which underestimate the risk because they don’t take inflammation into account,” says Dr. Liao. “In the future, screening for CVD in RA may include directly measuring the impact of inflammation using information available from routine cardiac stress tests. In many cases, the data may already be there; we just need to extract and calculate information to assess for [coronary microvascular dysfunction].”