Background: The main aim of the present study was to compare the occurrence of inflammatory cell infiltrates in the aorta, a vessel with a high occurrence of atherosclerosis, with that in the saphenous vein (SV) and internal mammary artery (IMA), which are protected from atherosclerosis.
Methods and results: Samples from the aorta, SV, and IMA of 65 patients with inflammatory rheumatic diseases (IRD) and from 51 control patients undergoing coronary artery bypass graft surgery were examined for the presence and location of inflammatory cell infiltrates and atherosclerotic lesions. Mononuclear cell infiltrates (MCIs) in the media or adventitia were observed in 2% IMAs, 17% SVs, and 35% aortic specimens (SV vs IMA: p=0.006; SV vs aorta: p=0.001). Atherosclerotic lesions were present in none IMA, 3% SVs and 18% aortic specimens. IRD and smoking increased the odds of MCI in the aorta (odds ratio (OR)=3.6, 95% confidence interval (CI): 1.6-8.5 and OR=4.0, 95% CI: 1.5-10.9), but not in the SV or IMA.
Conclusions: The occurrence of medial and adventitial MCI in the aorta, SV, and IMA paralleled each vessel's susceptibility to atherosclerosis: it was highest in the aorta and lowest in IMA. Local vascular inflammation may be involved in atherogenesis, and influence the patency of vascular grafts.