Early wave reflection of carotid artery is associated with 18F-FDG PET hypometabolism in Alzheimer's brain areas of cognitively normal adults.

Introduction: Arterial stiffening likely plays a role in Alzheimer disease (AD) pathogenesis. The current study investigated whether inter-individual variations in arterial stiffness and pressure wave parameters were associated with 18F-FDG positron emission tomography (PET) metabolism in AD-associated brain areas throughout adulthood, independently of age and before the onset of any neuropsychological disorders.

Methods: A prospective, large age-range population of 67 patients (17 young, 16 middle-aged, and 34 older adults; 37 women) underwent a: brain 18F-FDG PET, blood pressure recording, and carotid/femoral pulse wave-based measurements, including the time-to-peak of the reflected backward carotid pulse wave (bT), on the same day. Multivariable and quantitative voxel-to-voxel analyses (P-voxel < 0.005, corrected for cluster volumes) were conducted to assess associations between vascular parameters and 18F-FDG PET metabolism in AD-associated brain areas.

Results: In the multivariable analysis, only increased age and decreased bT were independently associated with the decline of metabolic activity in AD-associated brain areas (P < 0.001). In the voxel-to-voxel analysis with age as a covariate, bT was strongly associated with the metabolic activity of 40 clusters in AD-associated brain areas (clusters cumulative volume: 63 cm3; T score max: 5.7).

Conclusion: In a large age-range population of adult patients, who are still unaffected by neuropsychological disorders, an early reflected arterial pressure wave, as evidenced by a decreased bT value, is strongly associated with hypometabolic activity of AD-associated brain areas, independently of age.