BackgroundCalcific aortic stenosis (AS) is an active process sharing similarities with atherosclerosis and chronic inflammation. The pathophysiology of AS is notable for three cardinal components: inflammation, fibrosis and calcification. Monocytes play a role in each of these processes. The role of circulating monocytes in AS is not clear. The aim of the present study was to study an association between cir-culating apoptotic and non apoptotic CD14+ monocytes and AS features.MethodsWe assessed the number of CD14+ monocytes and apoptotic monocytes in 54 patients with significant AS (aortic valve area 0.74 ± 0.27 cm2) and compared them to 33 patients with similar risk factors and no valvular disease. The level of CD14+ monocytes and apoptotic monocytes was assessed by flow cytometry.ResultsThere was no difference in the risk factor profile and known coronary or peripheral vascular diseases between patients with AS and controls.Pa-tients with AS exhibited increased numbers of CD14+ monocytes as compared to controls (9.9% ± 4.9%vs. 7.7% ± 3.9%,P= 0.03). CD14+ monocyte number was related to age and the presence and severity of AS. In patients with AS, both CD14+ monocytes and apoptotic mono-cytes were inversely related to aortic valve area.ConclusionsPatients with significant AS have increased number of circulating CD14+ monocytes and there is an inverse correlation between monocyte count and aortic valve area. These findings may suggest that inflammation is operative not only in early valve injury phase, but also at later developed stages such as calcification when AS is severe.