Silent Cerebral Microbleeds and Longitudinal Risk of Renal and Cardiovascular Events in Patients with CKD.

BACKGROUND AND OBJECTIVES: In the general population, the presence of cerebral microbleeds on T2*-weighted magnetic resonance imaging has been reported to be a predictor of future stroke. Patients with CKD have a high prevalence of microbleeds and are at higher risk of ESRD as well as cardiovascular disease, including stroke. Because endothelial dysfunction is the common pathophysiology among microbleeds, CKD, and cardiovascular disease, we hypothesized that the presence of microbleeds would be an important predictor of composite outcome, including both cardiovascular disease and renal events, in those with CKD. DESIGN, SETTINGS, PARTICIPANTS, & MEASUREMENTS: This was a prospective cohort study of 404 patients with CKD who underwent T2*-weighted magnetic resonance imaging for this study between January of 2008 and January of 2011. The primary outcome was composite of cardiovascular and renal outcomes. Cardiovascular outcomes included cardiovascular death, the new onset of myocardial infarction, coronary revascularization, stroke, and amputation/revascularization because of peripheral artery disease. Renal outcomes included doubling of the serum creatinine level and development of ESRD requiring dialysis or transplantation. RESULTS: At baseline, microbleeds were present in 83 (20.5%) patients. During the follow-up median period of 2.3 years, 124 of the 404 patients experienced the composite outcome. The presence of microbleeds was associated with higher risk for the composite outcome in an unadjusted Cox model, and it remained significant after adjustment for age, sex, diabetes, and systolic BP (hazard ratio [HR], 2.58; 95% confidence interval [95% CI], 1.68 to 3.46 for composite outcome; hazard ratio, 2.41; 95% CI, 1.55 to 3.77 for renal outcome; hazard ratio, 3.46; 95% CI, 1.62 to 7.43 for cardiovascular disease outcome). CONCLUSIONS: In patients with CKD, the presence of microbleeds is a novel and independent predictor of both renal and cardiovascular disease end points.