Background and purpose: Myeloid-related protein (Mrp) 8/14 complex is the functional relevant form of Mrp-8 and Mrp-14. Mrp-8/14 complex is actively formed in the cytoplasm of circulating neutrophils and monocytes and then secreted. Plasma Mrp-8/14 complex is emerging as a new biomarker that may discriminate between patients with an acute coronary syndrome and those with stable coronary heart disease. Little is known about the predictive value of Mrp-8/14 plaque and plasma levels for cardiovascular events after atherectomy.
Methods: Plasma and plaque Mrp-8/14 levels were determined by ELISA in 230 consecutive patients (mean age 73) who underwent carotid endarterectomy. Patients were followed for 3 years for recurrent cardiovascular events (vascular death, nonfatal vascular event, and peripheral intervention). During follow-up, 62 patients experienced an event. Baseline Mrp-8/14 levels were higher in patients who experienced an event than in event-free patients (plasma 0.78+/-0.63 versus 0.57+/-0.67 mg/L; P=0.030 and plaque 0.54+/-1.23 versus 0.08+/-1.51 mg/kg; P=0.027). In a Cox model, a 1 U increase in log Mrp-8/14 was associated with an increased risk of recurrent events (plasma, hazard ratio [HR], 1.51; 95% CI, 1.02 to 2.23, P=0.040; and plaque, HR, 1.23, 95% CI, 1.04 to 1.46, P=0.018). After multivariate adjustment for risk factors (both plasma and plaque Mrp-8/14) and plaque characteristics (only plaque Mrp-8/14), the HR remained the same for both plasma (HR, 1.50, 95% CI, 1.01 to 2.30; P=0.046) and plaque (HR, 1.20, 95% CI, 1.01 to 1.44; P=0.042).
Conclusions: High Mrp-8/14 plasma and plaque levels are related to an increased risk of adverse cardiovascular events after a carotid endarterectomy, independent of traditional cardiovascular risk factors.