Cerebral Blood Flow Velocity and Vasomotor Reactivity During Autonomic Challenges in Heart Failure

Abstract

Background Significant alterations in autonomic nervous system (ANS) function, vasomotor reactivity, and cerebral blood flow may develop from damage to brain ANS regulatory areas in heart failure (HF). This preferentially right-sided injury occurs largely in autonomic structures perfused by the middle cerebral artery. Indications of altered, asymmetrical perfusion raise the potential for further neural damage. Objectives To determine whether the extent of middle cerebral artery blood flow velocity and vasomotor reactivity is altered on one side of the brain over the other in HF vs. control subjects, three ANS challenges were administered—each challenge recruited ANS regulatory areas potentially injured in HF. Methods Transcranial Doppler ultrasonography was used to measure cerebral blood flow velocity and vasomotor reactivity in 40 HF (mean age = 52.7 years, SD = 7.5; 27 males; left ventricular ejection fraction 26.8, SD = 8.3) and 42 control subjects (mean age = 48.3 years; SD = 6.0; 22 males) during 5% CO2 and hyperventilation, Valsalva, and orthostatic (upper body tilt) challenges. Results Lower cerebral blood flow velocity and abnormal vasomotor reactivity (p < .01) were noted in HF middle cerebral arteries during all challenges. More right-sided flow velocity reductions appeared in HF, with laterality differences noted during CO2 and orthostatic (p < .05), but not Valsalva challenges. Discussion Diminished cerebral blood flow velocity and altered vasomotor reactivity were associated with HF, changes being preferentially on the right-side; the asymmetry was more pronounced during CO2 and orthostatic challenges. The impaired blood flow regulation may contribute to the lateralized brain pathology in ANS areas, undermining autonomic control in HF.

Dynamics of cerebral blood flow in patients with mild non‐ischaemic heart failure

“…Comparing our results with previous reports on cerebrovascular reactivity in HF patients, our results are quite similar to those of Georgiadis et al These authors also found a significant decrease in VMR, even in NYHA class II patients, but also in NYHA classes III and IV. Moreover, Serber et al reported similar results, although the right/left asymmetry that they found was absent in the present study. The difference between these studies and the present study is that, in our study, these findings are further supported by a similar abnormality in NIRS‐based VMR, and by the finding of a disturbed dynamic autoregulation system.…”

Early abnormalities of cerebral blood flow in mild non‐ischaemic heart failure: part of a whole‐body response?

“…There is a very significant risk of a type 2 statistical error in a comparison of only 15 patients with 15 controls and significant differences may well have been found with larger patient numbers or if the patients had been older, had more severe CHF, or had fewer selection criteria applied. In addition, in my view, the isolated reduction in basilar artery flow in the presence of normal cerebral perfusion in the subtended brain areas remains speculative and may not prove to be a reliable finding, such as the fact that the right–left differences earlier described by Serber et al . were not confirmed in this study.…”

Protocol for the Isolation and Super-resolution dSTORM Imaging of RyR2 in Cardiac Myocytes

“…In the present study, common carotid artery but not internal carotid artery was used for flow measurement given the easier access due to the size of the animal studied and as previously reported [34,42]. Interestingly, CBF does not reduce uniformly in patients with heart failure with the right hemisphere being more affected [48]. Multiple studies reported that heart failure induces more damage on the right side of brain affecting structures responsible for autonomic nerve regulation [48,49].…”

“…Interestingly, CBF does not reduce uniformly in patients with heart failure with the right hemisphere being more affected [48]. Multiple studies reported that heart failure induces more damage on the right side of brain affecting structures responsible for autonomic nerve regulation [48,49]. Therefore the RCCA was used for CBF assessment in our study.…”