Blood pressure variability is altered in secondary progressive multiple sclerosis but not in patients with a clinically isolated syndrome.

OBJECTIVES: To investigate differences in beat-to-beat systolic blood pressure variability (SBPV) in people with secondary progressive MS (pwSPMS), clinically isolated syndrome (pwCIS) and healthy controls (HC). METHODS: This retrospective case-control study included 46 pwSPMS, 46 pwCIS and 44 HC. A semi-automated software made with MATLAB R2019b (The MathWorks, Inc.) was used for the evaluation of SBPV. The frequency domain characteristics observed were the power spectrum in the LF and HF bands and the LF/HF ratio. Data is expressed in absolute power (mmHg2) of LF and HF and ratio (LF/HF) during both supine and tilt-up phases of testing. RESULTS: There were no significant differences in mean systolic (sBP) or diastolic blood pressure (dBP) values during supine and tilt-up phases of testing between groups. During the supine phase of testing LF and LF/HF were significantly lower in the SPMS group (4.17±5.38 and 3.52±2.34, respectively) compared to the CIS (5.42±3.59, p = 0.015 and 5.92±4.63, p = 0.029, respectively) and HC group (6.03±4.55, p = 0.011 and 6.52 ±â€¯5.09, p = 0.010, respectively), while during the tilt-up phase, LF was significantly lower compared to both the CIS and HC group, and HF was significantly lower only compared to the CIS group. CONCLUSION: SBPV is altered in pwSPMS compared to pwCIS and normal controls. Further research in the field of MS related dysautonomia is warranted not only because of its relevance to comorbidities and MS symptoms, but also because of its likely involvement in the pathophysiology of MS.

Comparison of baroreflex sensitivity indices with standard tests of autonomic nervous system function.

OBJECTIVE: In order to further evaluate clinical usefulness of α- and ß-adrenergic components of the baroreflex sensitivity (BRS) index, the aim of this study was to compare them to standardized measures of the autonomic dysfunction. METHODS: In 275 participants (mean age 40.57 ± 15.19, range 18 to 89 years, 76.4% females) referred for testing of the autonomic nervous system, α-BRSa, ß-BRSa and BRSv were compared to heart rate (HR) and blood pressure (BP) values, adrenergic and cardiovagal indices of the Composite Autonomic Severity Score (CASS) and heart rate variability (HRV) parameters. RESULTS: α-BRSa showed statistically significant positive correlation with HR in the supine position and negative with the adrenergic index. ß-BRSa showed statistically significant negative correlation with tests for parasympathetic nervous system function. BRSv showed statistically significant negative correlation with all HR and BP parameters and positive with all HRV parameters. In a univariable logistic regression analysis, α-BRSa was a negative predictor (Exp(B) 0.866, 95% CI 0.782-0.959, p = 0.006, respectively) of the pathological adrenergic index. To differentiate between subjects with normal and pathological adrenergic index, the optimal cutoff for α-BRSa was found to be 6.741, which gave a sensitivity of 61.0% and a specificity of 56.0%. CONCLUSION: BRSa indices showed a good correlation with standard measures of ANS function. The most promising test was α-BRSa, which performed well as a α adrenergic receptors mediated sympathetic nervous system marker.