Peritoneal dialysis patients exhibit cognitive deficits but not ischemic brain injury: A magnetic resonance spectroscopy & diffusion tensor imaging study

Abstract

Background

Maintaining neurocognitive function is essential in the care of patients requiring dialysis. Currently, it is known that intradialytic systemic injury occurs during hemodialysis (HD) leading to ischemic injury and subcortical abnormalities that correspond to neurocognitive impairments. However, the pathophysiology of the intradialytic effects of peritoneal dialysis (PD) on the brain and neurocognitive function is unknown.

Methods

Patients completed a neurocognitive battery (The Montreal Cognitive Assessment [MoCA], Trails Making Test [TMT], and Cambridge Brain Science [CBS]), a diffusion tensor imaging scan, and proton magnetic resonance spectroscopy (¹H-MRS). Imaging and neurocognitive assessments were performed before PD exchange, with repeat imaging after 90 min of dwell time.

Results

Twelve patients receiving PD were studied. Patient demographics included (mean ± SD): 67 ± 8 years, 75% male, 75% diabetic, with a dialysis vintage of 18 ± 9 months. Intradialytic ¹H-MRS detected a 21% increase in glucose after 90 min (p = 0.006); however, no acute white matter effects were evident. The neurocognitive battery indicated that most impairment was seen on the TMT A/B (92%/50% impaired), indicating impairments in attention and executive function. Four CBS tasks showed impairment representing verbal, short-term memory, and reasoning impairments. Finally, 17% of the cohort was impaired on the MoCA.

Conclusions

This study demonstrated that PD is not associated with the same acute intradialytic ischemic injury routinely experienced by patients receiving HD, which may indicate that PD has a neuro-hemodynamic protective effect. However, those receiving PD did experience metabolic stress in the form of significant cerebral hyperglycemia, which may precipitate neurocognitive impairments indicating further investigation is warranted.