Usefulness of Apolipoprotein E4 and Distribution of Petechial Hemorrhages in Differentiating between Cerebral Amyloid Angiopathy and Hypertensive Intracerebral Hemorrhage

ABSTRACT

BACKGROUND AND OBJECTIVES: Cerebral amyloid angiopathy (CAA) accounts for a significant proportion of spontaneous lobar hemorrhages in the elderly population but hypertension is responsible for most cases of deep-seated hemorrhage. Reportedly petechial hemorrhages (PHs) can be associated with CAA or chronic hypertension. We determined the location of PHs and apolipoprotein E (APOE) genotype in intracerebral hemorrhage (ICH) patients and tried to correlate them with CAA associated or hypertensive ICH. METHODS: One hundred and sixty-two consecutive patients with primary ICH were evaluated clinically and by MRI. PHs were defined as small low-signal lesions (less than 1 cm) seen on T2-weighted or gradient-echo MR images. ICH and PHs were divided into lobar (cortical-corticosubcortical), deep (basal ganglia, thalamus, pons, or cerebellum), or mixed. APOE genotype was determined by polymerase chain reaction. All 162 patients were classified into 4 groups 1) probable CAA (multiple lobar bleeds without other cause), 2) possible CAA (single lobar bleed), 3) probable hypertensive ICH (deep bleed), and 4) mixed lobar and deep hemorrhages. RESULTS: Among 162 patients, 31 belonged to the probable and possible CAA groups and 17 of them showed PHs (7 lobar, 4 deep, 6 mixed). One hundred and twenty-two patients were the hypertensive ICH group and 63 of them had PHs (2 lobar, 10 mixed, 51 deep). Lobar PHs were more frequently observed in the probable and possible CAA group than the hypertensive ICH group (22.6% 1.6%, p < 0.01) while deep PHs were seen mainly in the hypertensive ICH group (41.8% 12.9%, p < 0.01) and these tendencies are also observed in the group who had taken both T2-weighted and gradient-echo MR images (64 patients). The frequency of hypertension was significantly lower in the probable and possible CAA groups with lobar PHs than in the hypertensive ICH group with deep PHs (57.1% 98 %, n = 7 & 51 respectively, p < 0.01). APOE ?4 frequency was probable (freq. 0.25, n = 2), possible CAA (freq. 0.21, n = 7), hypertensive (freq. 0.056, n = 9), and mixed hemorrhages (freq. 0.071, n = 7). The frequency of APOE ?4 of probable and possible CAA group seems to be higher than that of normal control (freq. 0.19, n = 146). CONCLUSION: APOE ?4 and PHs in lobar areas may be associated with hemorrhages restricted to lobar regions while hypertension and PHs in deep areas, with hemorrhages restricted to deep regions.