Abstract
BACKGROUND: Decreases in circulating CD34-positive cells are associated with increases in cardiovascular events. We investigated the association between the number of CD34-positive cells and the progression of coronary artery calcification (CAC), a marker of atherosclerosis, in patients with hypercholesteremia under statin therapy in a sub-analysis of a multicenter study. METHODS: In the principal study, patients with CAC scores of 1-999 were treated with pitavastatin. Measurement of CAC by non-enhanced computed tomography and a blood test were performed at baseline and at 1-year follow-up. Patients were divided into two groups: CAC progression (change in CAC score > 0) and non-progression. The number of circulating CD34-positive cells was counted using flow cytometry. RESULTS: A total of 156 patients (mean age 67 years, 55% men) were included in this sub-analysis. CD34 positive cell numbers at baseline as a continuous variable was inversely correlated with annual change in the log-transformed CAC score (r = -0.19, p = 0.02). When patients were divided into high and low CD34 groups based on the median value of 0.8 cells/μL, the adjusted change in CAC score in the low-CD34 group was significantly greater than that in the high-CD34 group (54.2% vs. 20.8%, respectively, p = 0.04). In multiple logistic analysis, a low CD34-positive cell number was an independent predictor of CAC progression, with an odds ratio of 2.88 (95% confidence interval 1.28-6.49, p = 0.01). CONCLUSIONS: Low numbers of CD34-positive cells are associated with CAC progression in patients with hypercholesterolemia under statin therapy. The number of CD34-positive cells may help to identify patients at increased cardiovascular risk.