Abstract 4854: Acute Systemic Inflammation Increases Central Blood Pressure and Pulse Wave Velocity in Healthy Subjects

Abstract

Objective. Acute systemic inflammation or infection transiently increases risk of cardiovascular events, but the underlying mechanisms are not fully understood. Although observational studies suggest that inflammation is associated with arterial stiffness and blood pressure, the causal relationship of this is not clear. We tested the hypothesis that induced acute inflammation causes an increase in blood pressure and arterial stiffness. Methods. Using a randomized double blind sham placebo-controlled cross over design, nineteen healthy subjects (male 10, female 9; age 24±4 yrs) were injected with an influenza vaccine (0.5m/L) as a model to generate systemic inflammation, and a sham vaccine (normal saline). C-reactive protein (CRP), interleukin 6 (IL-6), tumor necrosis factor-alpha (TNF-a) were measured as a markers of inflammation. Central aortic blood pressure was measured by radial artery tonometry and a generalized transfer function. Carotid-radial pulse wave velocity (PWV) was measured using applanation tonometry. These variables were measured at baseline 24 hours and 48 hours after each vaccination. Results. The influenza vaccination caused a significant increase in CRP (1.42±0.6 at baseline, 2.81±1.0 after 24 hours, 5.0±1.3mg/L after 48 hours, p<0.05) and IL-6 (1.12±0.3, 2.56±0.4, 2.26±0.6, p<0.05) but not TNF-a compared with sham placebo. Brachial artery systolic blood pressure was not significantly increased after an influenza vaccination (115.9±9.9, 118.8±10.9, 118.3±10.2mmHg, NS). However, central systolic blood pressure (98.0±7.4, 104.5±10.8, 100.7±8.4mmHg, p<0.05) and PWV (7.8±0.9, 8.6±1.5, 8.7±1.3m/s, p<0.05) were significantly increased after an influenza vaccination but not sham vaccination. Conclusions. These findings show that an acute inflammation caused a temporary increase in central blood pressure and arterial stiffness. This offers insight regarding the noted increased risk of cardiovascular events associated with acute systemic inflammation. This research has received full or partial funding support from the American Heart Association, Midwest Affiliate (Illinois, Indiana, Iowa, Kansas, Michigan, Minnesota, Missouri, Nebraska, North Dakota, South Dakota & Wisconsin).