Dissecting the Vascular-Cognitive Nexus: Energetic vs. Conventional Hemodynamic Parameters

Background Blood flow measurements are being studied in relation to vascular health and cognitive function, but their role is unclear. Objective We investigated whether energetic hemodynamic parameters, such as aortic and carotid mean and pulsatile energy, and energy pulsatility index (PI), provide a more nuanced understanding of the vascular-cognitive link, as assessed by the Montreal Cognitive Assessment (MoCA), than conventional flow and flow PI. Methods Cognitive evaluation and hemodynamic measurements, including aortic and carotid pressure and flow waves, were performed on 1858 MoCA participants. Energy was calculated by integrating pressure time flow. An asymmetric bifurcation model was used to calculate aortic and carotid mean, pulsatile energy, and hemodynamic parameters across the interface. Results After adjusting for age, sex, education, depression score, heart rate, BMI, HDL-cholesterol, and glucose levels, energetic hemodynamic parameters were more associated with MoCA score than aortic and carotid flow and flow PI. In particular, carotid mean energy was most significantly positively associated with MoCA (standardized beta = 0.053, P = 0.0253) and energy PI was most significantly negatively associated (standardized beta = -0.093, P = 0.0002), surpassing conventional metrics like carotid PI. Aortic pressure reflection coefficient at the aorta-carotid bifurcation was positively correlated with mean carotid energy and weakly negatively correlated with PI. Aortic characteristic impedance positively correlated with carotid energy PI but not mean energy. Conclusion Our study shows that energetic hemodynamic parameters, particularly carotid mean energy and energy PI, better explain the vascular-cognitive nexus than conventional measures. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement Supported by the Mistry of Science and Technology, Taiwan, ROC. (MOST- MOST 109 2314 B 400 029-, MOST-110-2314-B-400 -052 -, MOST 109-2314-B-010-060 -, MOST 110-2314-B-A49A-545 -) ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Not Applicable The details of the IRB/oversight body that provided approval or exemption for the research described are given below: or the cardiovascular hemodynamic assessments, these two study cohorts have adopted the same study protocol, which has been approved by the Institutional Review Board of National Yang Ming Chiao Tung University. Each participant was well-informed, and a written consent was obtained before the study. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Not Applicable I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Not Applicable I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Not Applicable The data can be made accessible upon reasonable request to the corresponding authors.