PS 05-36 NATURAL HISTORY OF CEREBRAL MICROBLEEDS IN A PROSPECTIVE STUDY

Objective: Cerebral microbleeds (CMBs) are widely accepted as a marker of vulnerability of the cerebral small vessels. However, the natural history of CMBs remains largely unknown. This study aimed to clarify the natural history of CMBs in a prospective manner. Design and Method: We performed yearly brain magnetic resonance imaging (MRI) assessments for 5 or more years in 36 non-valvular atrial fibrillation outpatients. Results: Among the 36 patients, 8 had CMBs present at baseline and 4 showed new CMBs on follow-up. We followed up 8 patients for 7 years, 2 patients for 8 years and 2 patients for 6 years. The CMBs disappeared in 4 patients during the follow-up duration. In 5 patients, the CMBs remained no-change over 7 years. Importantly, we observed new appearance of CMBs in 2 patients without hypertension, and they disappeared after 2 and 4 years from their appearance, respectively. Conclusions: We could find the natural history of CMBs using yearly performed MRIs for over 5 years in a prospective manner. Most CMBs seemed to remain for over 7 years. Hypertension may keep microbleeds alive. Because of its refined nature, the detection and confirmation of CMBs are not always perfectly impeccable. Further surveillance in many subjects and a long-term prospective follow-up are required.