Systematic Review of Cardiovascular Autonomic Dysfunction in Lewy Body Dementia

Introduction: 

The Lewy Body Dementias (LBD) incorporate both Parkinson’s Disease Dementia (PDD) and Dementia with Lewy Bodies (DLB). These conditions have a heterogeneous presentation and disease trajectory with much inter-individual variability. Accurate diagnostics and prognostication are becoming increasingly important in the potential disease modifying era. 

Cardiovascular autonomic dysfunction is a supportive diagnostic feature of DLB and a well-known non-motor phenotype of Parkinson’s Disease. It most commonly presents with orthostatic hypotension (OH) which can be easily measure clinically using simple lying and standing blood pressure. Literature suggests that cardiovascular autonomic dysfunction can be an early feature, is heterogeneous and may represent sensitive markers of disease progression that can be easily assessed clinically. 

Methods: 

This systematic review addresses whether cardiovascular autonomic dysfunction, particularly orthostatic hemodynamics, predicts prognosis and phenoconversion in alpha-synucleinopathies. Independent researchers reviewed cohort, observational, longitudinal, and epidemiological studies from EMBASE, Web of Science, CINAHL, and Google Scholar.  

Results: 

From an initial 4,986 titles, 17 studies met the inclusion criteria. OH showed the strongest and most consistent association with cognitive decline and adverse outcomes in LBD. Other cardiovascular autonomic markers showed limited or inconsistent associations. OH and blunted heart rate response showed the strongest evidence as a potential predictor of phenoconversion to LBD. Other cardiovascular autonomic markers showed mixed or largely negative predictive value. 

There was a broad heterogeneity of study design across the included literature with differences in autonomic testing protocols and variable outcome definitions. The studies were largely cross-sectional with small sample sizes and moderate study quality overall.  

Conclusion: 

 
OH and blunted heart rate response emerge as the most consistent cardiovascular autonomic markers associated with adverse outcomes and phenoconversion in LBD. However, significant heterogeneity and methodological limitations across studies highlight the need for larger, standardised longitudinal studies to establish their prognostic utility.