Objective: Patients with rheumatoid arthritis (RA) are at increased risk for cardiovascular diseases (CVD). We compared the histologic features of coronary artery disease in patients with RA and non-RA controls.

Methods: Forty-one RA patients who died and underwent autopsy between 1985 and 2003 were matched to 82 non-RA controls of the same age and sex with similar history of CVD and autopsy date. Coronary arteries were submitted for histologic evaluation. The grade of stenosis was evaluated in each artery. The numbers of vulnerable plaques and acute coronary lesions were counted. The composition of a representative stable and vulnerable plaque from each vessel was evaluated. Chi-square tests were used to compare differences between groups.

Results: Patients and controls had similar age at death (mean 79 yrs) and 61% were female in both groups. Overall, there was no significant difference in grade of stenosis or number of acute coronary lesions. Among subjects with CVD, 54% of controls had grade 3-4 lesions in left main artery versus only 7% of patients (p = 0.023). Vulnerable plaques in left anterior descending (LAD) artery were significantly more common in patients than controls (p = 0.018). Inflammation was observed more frequently in patients, in both the media of left circumflex (p = 0.005) and adventitia of LAD artery (p = 0.024). Similar trends were seen for subjects with heart failure.

Conclusion: There was less histologic evidence of atherosclerosis but greater evidence of inflammation and instability in RA patients compared to controls. These differences suggest that the mechanisms responsible for cardiovascular morbidity and mortality may be different in patients with RA.