Acute systemic inflammation reduces both carotid and aortic wave reflection in healthy adults

Acute inflammation increases the risk of cardiac and cerebrovascular events, possibly related to alterations in the hemodynamic load. Wave reflection at the aorta and carotid provides insight into downstream vascular changes and hemodynamic load at the heart and brain. Acute inflammation has been suggested to reduce wave reflection via downstream vasodilation; however, this is not firmly established and has only been investigated at the aorta. We sought to explore the effect of acute inflammation on aortic and carotid hemodynamics in healthy, young adults. Pressure waveforms were collected via radial and carotid applanation tonometry in 23 adults (26 ± 4 years) before and 24 h after a typhoid vaccination. Waveforms were calibrated to brachial mean and diastolic pressure, and waveform separation analyses (WSA) were performed, yielding augmentation index, reflection index, time to reflection (Tr), forward (Pf) and reflected (Pb) wave magnitude, and pulse wave velocity. Arterial diameters and carotid stiffness were measured via ultrasonography. Acute inflammation reduced wave reflection at 24 h in both the aorta and carotid (P < 0.05) without changes in mean pressure. WSA did not reveal independent changes in Pf, Pb, or Tr (P > 0.05). Arterial stiffness did not change; however, brachial and carotid artery diameters increased. Acute inflammation reduces wave reflection in the aorta and carotid artery in young adults, potentially due to downstream/peripheral vasodilation. Reduced aortic wave reflection did not disturb the cardiac workload; however, reductions in carotid wave reflection may render the brain vulnerable to pulsatile hemodynamics. These findings may have implications for cardiac and cerebrovascular risk during acute inflammation.