The Connection Between Cognitive and Cardiac Function Following Kidney Transplant: The VINTAGE Study

Rationale & Objective

The effects of successful kidney transplant (KT) on cognitive function remain unclear. To clarify how the presence or absence of pre-KT mild cognitive impairment (MCI) affects cognitive changes (overall and domain) after KT. To determine whether the cognitive improvement after KT is associated with improved cardiac function.

Study Design

A hybrid retrospective and prospective observational cohort study.

Setting & Participants

We obtained data from 70 recipients who underwent living donor KT (2017-2021).

Predictors

Pre-KT MCI status and left ventricular (LV) remodeling.

Outcomes

Changes in mean Montreal cognitive assessment (MoCA) scores before and after KT.

Statistical Analysis

We evaluated whether the presence or absence of pre-KT MCI modified the effect of KT (total and each domain). We also evaluated the association between changes in MoCA total score and LV reverse remodeling effect.

Results

MoCA total score: no significant change was observed in the non-MCI group (27.6 ± 1.2 to 27.6 ± 1.6, P = 0.81). In contrast, the score in the MCI group improved from 22.9 ± 2.0 to 24.7 ± 2.0 (P < 0.001; P_int < 0.001). MoCA domain score: the effect of KT varied between the non-MCI group and the MCI group in each domain; the visuospatial and executive domains increased for the MCI group but not non-MCI group (P_int = 0.01). Cognitive and cardiac function: improvement in MoCA score was positively correlated with the effect of LV reverse remodeling (P = 0.02), even after adjusting for age and tacrolimus trough level.

Limitations

Incomplete cerebral blood flow data.

Conclusions

The effect of KT was changed by pre-KT MCI status. Heterogeneous cognitive improvement after KT can be explained by the LV reverse remodeling effect.

Plain-Language Summary

Kidney transplant can greatly improve health, but how they affect thinking skills wasn’t fully understood, especially in people with mild thinking problems before the transplant. We looked at 70 patients. We compared their thinking skills before and after the transplant. We found that for those with normal thinking before, their scores didn’t change much. But surprisingly, people with mild thinking problems actually showed improvement in their thinking skills after the transplant. We also saw a link between this improvement in thinking and the heart getting healthier after the transplant. Our study suggests that a successful kidney transplant might help improve thinking in those who had some difficulties beforehand, and this could be related to better heart function.