Prognostic significance of circulating leukocyte subtype counts in patients with coronary artery disease.

BACKGROUND AND AIMS: This study investigated the association of leukocyte subtype counts with vascular endothelial dysfunction and future cardiovascular events in patients with coronary artery disease (CAD).

METHODS: The study included 389 consecutive CAD patients (259 male, 130 female; mean age, 70.1 ± 9.9 years). The patients underwent coronary angiography, and measurement of blood parameters, including leukocyte subtype counts.

RESULTS: There were 84 cardiovascular events during a mean follow-up of 586 ± 378 days. Kaplan-Meier analysis showed a higher probability of cardiovascular events in the high-monocyte group (≥360/mm3 ) compared with the low-monocyte group (<360/mm3 ) (log-rank test, p = 0.047). Multivariate Cox hazard analysis identified a high monocyte count as an independent predictor of cardiovascular events (hazard ratio: 1.63, 95% confidence interval:1.05-2.51, p = 0.028). Peripheral endothelial function in 355 of the CAD patients was assessed by reactive hyperemia peripheral arterial tonometry index (RHI) to examine the association of ln-RHI with leukocyte subtype counts. Total leukocyte, monocyte and neutrophil counts were significantly higher in CAD patients with low ln-RHI (<0.57: the mean ln-RHI value) compared with those with high ln-RHI (≥0.57). Univariate analyses revealed that ln-RHI in CAD patients was positively correlated with ln-total leukocyte (r = -0.187, p < 0.001), ln-monocyte (r = 0.316, p < 0.001), and neutrophil (r = -0.175, p = 0.001) counts. Multiple regression analysis showed that the monocyte count was a significant and independent factor associated with ln-RHI (adjusted R2  = 0.126, p < 0.001).

CONCLUSIONS: A high monocyte count was an independent and incremental predictor of cardiovascular events in CAD patients. The monocyte count was also significantly correlated with peripheral endothelial dysfunction in CAD patients.