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

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

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.

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).

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.