P169 - RELATIONSHIP BETWEEN CARDIORESPIRATORY FITNESS, CEREBROVASCULAR STIFFNESS, RESISTANCE AND COGNITIVE PERFORMANCE IN PATIENTS WITH HEART FAILURE

Background: Cardiorespiratory fitness (V̇O2peak) is a key marker of cardiovascular health and is reduced in individuals with heart failure (HF) due to cardiopulmonary and vascular impairments. Nearly 50% of HF patients present cognitive impairment, partly explained by increased aortic stiffness, which elevate systolic pressure and reduce cerebral perfusion. While aortic stiffness has been studied in this context, cerebral arterial stifness (AS) and cerebrovascular resistance (VR), potentially affecting cognitive function, remain poorly investigated in HF patients. The relationship between V̇O₂peak, AS, VR, and cognition thus warrants further exploration. The objective is to investigate the relationship between V̇O₂ peak, AS, VR and cognition in patients with HF. We hypothesized that V̇O₂peak will predict AS and VR, and that these will predict cognitive functions.

METHODS AND RESULTS: Forty-eight participants (66±8 years old,14 women) with HF underwent a cardiopulmonary exercise test with gas exchange analysis. V̇O₂ peak was expressed as a percentage of the predicted value (%V̇O₂peak). A transcranial Doppler (TCD), simultaneous with an ECG, measured blood velocity in the middle cerebral artery (MCA) to calculate AS and VR. Participants also completed a battery of neuropsychological test including the Montreal Cognitive Assessment (MoCA) for global cognition, the Trail Making Test A and B (TMT), the Stroop test, and the Digit Symbol Substitution Test (DSST) for executive functions and processing speed, phonemic fluency (letter P), and the Rey Auditory Verbal Learning Test (RAVLT) for episodic memory .
Simple linear regressions indicated that %V̇O2peak was significantly associated with VR (p=0.009,R²=0.391) and AS (p=0.010,R²=0.148). Notably, the regression coefficients indicated very small variations where a 10% increase in %V̇O2peak was associated with a slight decrease in VR (mean=0.62±0.11;β=-0.03) and a small decrease in AS (mean=0.28±0.07;β=0.02). Furthermore, multiple linear regression analyses controlling for age, sex, and education demonstrated that, among all cognitive measures, only performance on TMT-A and TMT-B was significantly predicted by AS (p=0.046,β=–120.46) and VR (p=0.020,β =–173.05), respectively.

Conclusion: %V̇O2peak results show the potential role of cardiorespiratory fitness in preserving central and cerebral vascular health in HF patients. Cognitive predictions reflect significant variations in task performance attributable to these two vascular parameters in HF patients. AS and VR are associated with distinct cognitive functions (processing speed and attention for AS, cognitive flexibility for VR) suggesting distinct contribution to cognitive aging. Modest associations with %V̇O2peak call to caution in interpretation warrant further investigation in larger, fitness-based intervention studies to clarify the heart-brain relationship in HF patients.