Our subjects consisted of 33 healthy normal controls (NC), 28 patients with PiB(−) svMCI, and 12 with PiB(+) svMCI. They underwent scanning capillary tube viscometer measuring BV during systolic and diastolic phases.
Compared with the NC group, the PiB(−) svMCI group showed increased diastolic blood viscosity (DBV) but no difference in systolic blood viscosity (SBV). By contrast, there was no significant difference in SBV and DBV between the NC and PiB(+) svMCI groups. Within the PiB(+) svMCI group, ApoE4(−) subgroup showed increased DBV compared with the ApoE4(+) subgroup.
Increased DBV is an important contributor to the development of “pure” svMCI (ie, without cerebral amyloid deposition). The relationship between BV and PiB(+) svMCI differed according to ApoE genotype, suggesting that the pathogenesis of PiB(+) svMCI might also be heterogeneous.