Prognostic value of neutrophils in patients with asymptomatic carotid artery disease.

BACKGROUND

Inflammation is associated with atherosclerotic disease. In this context, it has been shown that an increased neutrophil count is a risk factor for cardiovascular events in patients with coronary and peripheral artery disease. However, the impact of neutrophils on long-term mortality in patients with carotid atherosclerosis is not yet fully understood.

METHODS

We prospectively studied 853 of 1268 consecutive patients with neurologically asymptomatic carotid stenosis for all-cause and cardiovascular death, respectively.

RESULTS

During a median follow-up time of 6.3 years (IQR 5.8-6.7 years) a total of 203 deaths (23.8%), including 134 cardiovascular deaths (15.7%), were recorded. An increase of 1 G/L of neutrophil count indicated an increased risk for all-cause mortality of 1.20 (CI [95%] 1.10-1.31, P < 0.001) and of cardiovascular death of 1.30 (CI 1.17-1.45, P < 0.001), respectively. For the second to the fourth quartile of the neutrophil count, adjusted hazard ratios for all-cause mortality were 1.12 (CI, 0.71-1.75), 1.46 (CI, 0.96-2.21), and 1.76 (CI, 1.15-2.69; P = 0.03 for trend); and 1.41 (CI, 0.80-2.49), 1.53 (CI, 0.88-2.68), and 2.54 (CI, 1.49-4.33; P < 0.01 for trend) for cardiovascular mortality, compared to the lowest quartile, respectively. Patients with baseline carotid stenosis of more than 50% and/or increased neutrophil count (≥median), had a 1.9-2.4 fold increase in risk of (CV-) death, compared to patients with carotid narrowing of less than 50% and/or neutrophil count less than the median (P < 0.001). After adjusting for cardiovascular risk factors, only neutrophils, but not eosinophils, basophils, monocytes, lymphocytes, or the total leukocyte count showed a significant association with long-term mortality. No significant association was found between white blood cell subtypes with either baseline degree or progression during a 6 month follow-up of carotid stenosis.

CONCLUSION

The baseline neutrophil count was an independent predictor for all-cause and cardiovascular mortality in neurologically asymptomatic patients with carotid stenosis. Thus, the measurement of neutrophils could provide prognostic information on outcome in patients at risk.