Reduced resting beat‐to‐beat blood pressure variability in multiple sclerosis

Abstract

Multiple Sclerosis (MS) is an autoimmune disease associated with central nervous system demyelination known to impair healthy autonomic function. We have previously demonstrated individuals with MS exhibit lower resting muscle sympathetic nerve activity and impaired carotid baroreflex control of arterial blood pressure compared to controls. Recently, increased resting beat-to-beat blood pressure variability (BPV) has been shown to be a strong predictor of cardiovascular risk in other clinical populations. Taken together, the aim of the current investigation was to test the hypothesis that resting beat-to-beat BPV is increased in individuals with MS compared to matched healthy controls. In 7 patients with relapsing-remitting MS (5 females/2 males, EDSS <4) and 7 sex-, age-, and weight-matched healthy controls, beat-to-beat blood pressure (Finometer) was recorded during 10 minutes of quiet supine rest. Individuals with MS had similar resting mean blood pressure (BP) compared to healthy controls (P= 0.736), however the BP standard deviation (SD) and coefficient of variation (CV) was less in MS (BP SD; MS: 3.2 ± 0.2 vs. CON: 4.0 ± 0.2, P=0.022 and BP CV; MS: 3.8 ± 0.3 vs. CON: 4.7 ± 0.2, P=0.025). Similarly, mean resting systolic blood pressure (SBP) was not different between MS and healthy controls (P=0.207) but the SBP standard deviation and coefficient of variation was less in MS (SBP SD; MS: 4.7 ± 0.4 vs. CON: 6.6 ± 0.5, P=0.013 and SBP CV; MS: 4.3 ± 0.4 vs. CON: 5.8 ± 0.4, P=0.033). In contrast, there was no difference in the DBP standard deviation or coefficient of variation between the two groups (P= 0.321 and P=0.295; respectively). In summary, contrary to our original hypothesis, individuals with MS exhibited reduced resting beat-to-beat BPV compared to healthy controls. These preliminary findings may be related to altered autonomic function in this clinical population.