Incidence of Symptomatic Hemorrhage in Patients with Lobar Microbleeds
van Etten ES, Auriel E, Haley KE, Ayres AM, Vashkevich AV, Schwab KM, et al. Incidence of Symptomatic Hemorrhage in Patients With Lobar Microbleeds. Stroke. 2014
Cerebral amyloid angiopathy (CAA) represents amyloid β-peptide deposition in small and medium-sized blood vessels in the brain, leading to hemorrhagic and ischemic injury. Lobar microbleeds on MRI have also been identified as a marker of CAA severity. There is estimation that prevalence of CAA in the elderly population is 11 to 24%. This number is expected to increase as the life expectancy increases. Need for use of anticoagulation also is expected to increase because of 2 reasons. A-Fib is condition more prevalent in elderly. We also achieved significant improvement in detecting paroxysmal A-Fib.
In this timely and well-conducted prospective study, 379 patients were enrolled between January 1993 and January 2012. Patients were grouped into two categories: those presenting with two or more lobar microbleeds in the absence of lobar ICH and those presenting with a lobar ICH with at least one lobar microbleed. In the second group, patients who survived the first 90 days after ICH were studied.
In addition to evaluation of fatality, ICH and white matter hyperintensity, Apolipoprotein E (APOE) genotype (ε2 and ε4 alleles) was determined in a large subset of patients.
Baseline demographics (age, gender), vascular risk factors, and APOE genotype did not differ significantly between microbleed-only and ICH groups. The lobar microbleed count was significantly higher in microbleed-only patients which was explained by referral of those patients.
In follow up, microbleed group had higher white matter hyperintensity (again explained by referral) and overall mortality. ICH group had higher rate of repeat ICH, but this did not reach statistical significance. Warfarin use and older age were independently associated with time to incident ICH. Use of ASA was not associated with increased ICH risk.
This study is highlighting that even patients with microbleeds in addition to those with CAA and ICH are at substantial risk future ICH. Also, it is raising very important question; whether this risk of future ICH is sufficient to tip the risk vs. benefit calculation away from anticoagulant treatment this significant subset of patients. This can only be answered in large, prospective trial. Till that time, caution with anticoagulation in patients with CAA.