Abstract 1549: Combined Use of Endothelium-Derived Microparticles and B-Type Natriuretic Peptide Incrementally Predicts Future Cardiovascular Events in Patients with Stable Coronary Artery Disease
Background: Endothelium-derived microparticles (EMPs) are a new plasma marker of endothelial dysfunction indicating vascular vulnerability. B-type natriuretic peptide (BNP) is a clinically useful marker reflecting myocardium vulnerability. We hypothesized that EMPs and BNP could independently predict future cardiovascular events.
Methods: We measured plasma levels of CD144 (VE-cadherin)-EMPs by flow cytometry and BNP levels by ELISA in consecutive patients with stable CAD (n = 132). We followed up the patients with stable CAD from 2003 to 2006. The primary end points were any of cardiovascular death; nonfatal myocardial infarction; unstable angina pectoris; sudden hospitalization for myocardial ischemia; coronary angioplasty to new lesions; and, stroke.
Results: The stable CAD patients, mean age 70.0 ± 9.3 years, 71% males, CD144-EMP median 0.658 × 106 /ml (range; 0.505 to 0.853), BNP median 56.0 pg/ml (range; 21.2 to 167.3), were followed up for 32 months. There were 17 cardiovascular events (12.9% of the patients). Kaplan-Meier analysis demonstrated that the patients with high EMPs levels or high BNP had significantly higher probability of cardiovascular events (log rank test, EMP p = 0.005, BNP p = 0.02). Higher EMPs levels and higher BNP levels were independent predictive markers of cardiovascular events (EMPs, odds ratio [OR] 5.01; 95% confidence interval [CI] 1.4 to 17.4; p = 0.01; and, BNP, OR 3.37; 95% CI 1.1 to 10.3; p = 0.03) by Cox proportional hazards analysis. There was no significant correlation between plasma levels of EMPs and BNP (r = 0.14, p = 0.10). All stable CAD patients were classified into 4 groups according to the median level of EMPs and BNP. High EMPs and high BNP group had 11 events; high EMPs and low BNP group had 3 events; low EMPs and high BNP group had 2 events; and, low EMPs and low BNP group had 1 event, indicating that combined use of EMPs and BNP incrementally predicted future cardiovascular events.
Conclusions: Plasma levels of CD144-EMPs are independent from BNP levels. Cardiovascular risk assessment by the combination of CD144-EMPs and BNP raises predictive value on the occurrence of cardiovascular complications. This strategy is clinically useful for detection of the vulnerable patients who need more aggressive treatments.