P320 Differences in adrenergic components of baroreflex response to Valsalva maneuver in patients with multiple sclerosis and healthy subjects

Abstract

Objectives To evaluate differences in recently developed, non-standard adrenergic baroreflex sensitivity (BRS) indices between patients with multiple sclerosis (MS) and healthy controls (HC). Methods This retrospective analysis included 153 patients with MS and 20 healthy controls. Systolic blood pressure (sBP) responses during Valsalva maneuver (VM) were divided into three subtypes: balanced – type 1 (a sBP dip below baseline in late phase II (IIL) and recovery in phase IV), suppressed – type 2 (a non-dipping BP) and augmented – type 3 (a BP recovery in phase IIL) autonomic response. Alternative adrenergic component of BRS (BRSa1), and alpha- ( α -BRSa) and beta-adrenergic ( β -BRSa) components of adrenergic BRS were calculated and compared between the groups. For a subset of 103 MS patients, data on epinephrine, norepinephrine and dopamine immediately prior to performing Valsalva maneuver were available for analysis. Results There was no difference in the subtypes of sBP responses during VM between groups. Patients with MS had significantly higher α -BRSa compared to HC (6.36 ± 2.44 vs. 5.02 ± 2.14, p = 0.02). No differences were found for BRSa1 and β -BRSa. When we looked at differences in all three parameters depending on subtypes of sBP responses during VM, significant difference in α -BRSa was maintained only for the subtype 3 (7.27 ± 2.05 vs. 5.88 ± 2.09, p = 0.045). We found positive correlation between epinephrine and BRSa1 (rs 0.226, p = 0.04), negative correlation epinephrine and β -BRSa (rs −0.195, p = 0.050) and positive correlation between norepinephrine and α -BRSa (rs 0.228, p = 0.021). Discussion It has been suggested that new BRSa measurements may help differentiate normal physiologic variants from mild dysautonomia. Conclusion Healthy subjects and MS patients exhibit different alpha-adrenergic response to Valsalva maneuver. Significance A significant correlation between blood catecholamines and alfa and beta adrenergic response to Valsalva maneuver was observed.