Combined use of endothelial function assessed by brachial ultrasound and high-sensitive C-reactive protein in predicting cardiovascular events

Background: Endothelial function plays a key role in determining the clinical manifestations of atherosclerotic lesions. Elevated high-sensitive C-reactive protein (hsCRP) relates to long-term prognosis of cardiovascular disease. Hypothesis: We test the hypothesis that combined use of endothelial function and hsCRP could increase predictive value of future cardiovascular events. Methods and Results: 205 patients were followed up for a median period of 24 months. Endothelial function was assessed using brachial ultrasound to measure endothelium-dependent flow-mediated vasodilation (FMD). Cox regression analyses were conducted for the 205 subjects, with cardiovascular events being defined as myocardial infarction, hospitalization due to congestive heart failure, percutaneous coronary intervention, coronary artery bypass grafting, and ischemic stroke. Twenty nine (14%) developed cardiovascular events. Both FMD and hsCRP were significantly predictive of cardiovascular events (relative risk for patients with FMD < 3% as compared to those with FMD > 6%, 4.65, 95% confidence interval (CI): 1.30-16.66, p = 0.018; relative risk for the highest as compared with the lowest tertile of hsCRP level, 3.59, 95% CI: 1.32-9.74, p = 0.012, respectively). Further risk analysis was performed among four groups classified by FMD (FMD ≥ 6% or < 6%) and half percentile of hsCRP (hsCRP ≥ 1 or < 1 mg/dL). Relative risks for the FMD < 6%/hsCRP ≥ 1 mg/dL group compared to FMD ≥ 6%/hsCRP < 1 mg/dL group increased markedly to 12.598 (95% CI: 1.69 to 94.14, p = 0.014) for cardiovascular events. Conclusions: Patients with suspected coronary artery disease may benefit from risk stratification based on both endothelium-dependent FMD and hsCRP, since combined these two factors contribute significantly toward the incidence of cardiovascular events.