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INFLUENCE OF ARTERIAL STIFFNESS ON CEREBROVASCULAR RESPONSE TO EXERCISE IN INDIVDIUALS POST-STROKE

Abstract

Arterial stiffness promotes the transmission of harmful pulsatile energy to the cerebrovasculature, causing microvascular damage and reduced cerebral blood flow. Post stroke, individuals exhibit increased arterial stiffness and are at an elevated risk for cerebrovascular decline. However, minimal research has explored the relationship between arterial stiffness and cerebral blood flow post stroke. PURPOSE: Examine the relationship between arterial stiffness and cerebral blood flow, as measured by middle cerebral artery blood velocity (MCAv), in individuals with stroke at rest and during exercise. METHODS: Participants, 20-85 years of age, 6 months to 5 years post stroke were included. We assessed arterial stiffness using carotid-femoral pulse wave velocity (PWV) for central arterial stiffness and waveform analysis for pulse wave mechanics: augmentation index (AIx), arterial pressure (AP). Transcranial doppler ultrasound was used to assess MCAv at rest and during moderate-intensity exercise. Heart rate was monitored to ensure exercise intensity. Data were sampled at 500 Hz and post-processed with a custom written MATLAB script to determine baseline (BL) MCAv, prior to exercise, and steady state (SS) MCAv during exercise. Linear regression was used to evaluate the relationship between MCAv, PWV, AIx, and AP. Data are presented as mean ± standard deviation. Statistical significance:  = 0.05. RESULTS: Participants (n = 24) were 20±17 months post stroke, 62±13 years, 50% female. Average BL and SS MCAv were 41±13 and 49±16 cm/s, respectively. Arterial stiffness values were elevated, with an average PWV of 10±2 m/s, AIx 35±10%, and AP 16±7 mmHg. We observed significant relationships between BL MCAv, AIx (p = 0.05,  = -0.52), and AP (p = 0.04,  = -0.83). Significant relationships were also observed between SS MCAv and PWV (p = 0.02,  = -3.58), AIx (p = 0.04,  = -0.67), and AP (p = 0.02,  = -1.12). CONCLUSION: Increased arterial stiffness negatively impacts cerebral blood velocity in individuals with stroke. As individuals post stroke are at an elevated risk for cerebrovascular decline, future research should explore interventions that target arterial stiffness improvement.

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