Comprehensive assessment of the global and regional vascular responses to food ingestion in humans using novel rapid MRI

Abstract

Comprehensive assessment of the global and regional vascular responses to food ingestion in humans using novel rapid MRI. Am J Physiol Regul Integr Comp Physiol 310: R541-R545, 2016. First published January 13, 2016 doi:10.1152/ajpregu.00454.2015.-Ingestion of food is known to increase mesenteric blood flow. It is not clear whether this increased flow demand is compensated by a rise in cardiac output (CO) alone or by redistribution of blood flow from other organs. We used a new comprehensive imaging method to assess the human cardiovascular response to food ingestion. Following a 12-h fast, blood flow in segments of the aorta and in organspecific arteries, and ventricular volumes were assessed in 20 healthy adults using MRI at rest and following ingestion of a high-energy liquid meal. Systemic vascular resistance (SVR) fell substantially and CO rose significantly. Blood pressure remained stable. These changes were predominantly driven by a rapid fall in mesenteric vascular resistance, resulting in over four times more intestinal blood flow. Renal vascular resistance also declined but less dramatically. No changes in blood flow to the celiac territory, the brain, or the limbs were observed. In conclusion, this is the first study to fully characterize systemic and regional changes in vascular resistance after food ingestion in humans. Our findings show that the postprandial drop in SVR is fully compensated for by increased CO and not by redistribution of blood from other organs. With the exception of a modest increase in renal blood flow, there was no evidence of altered blood flow to nondigestive organs. The proposed oral food challenge protocol can be applied safely in an MRI environment and may be useful for studying the involvement of the gut in systemic or cardiovascular disease.

Longitudinal Parameter Estimation in 3D Electromechanical Models: Application to Cardiovascular Changes in Digestion

“…The first remark is that on average, the parameters R which models the arterial peripheral resistance decreases by 14%. This was expected and corresponds to findings in [3]. In a clinical setting the peripheral resistance is indeed computed as the ratio between the blood flow and the blood pressure, and a similar relationship can be derived in the model: as shown in Fig 2a the ratio (MP-P ve )/CO is almost exactly equal to the peripheral resistance R in our simulations.…”

“…More than 80 patients participated to a clinical study to assess the cardiovascular response after the ingestion of a high-energy (1635 kcal), high-fat (142g) meal after fasting for 12h, following the stress protocol in [3]. Informed consent was obtained from the subjects and the protocol was approved by the local Research Ethics Committee.…”

“…A clinical study was performed in [3] to assess the cardiovascular response to a food stress protocol, involving the ingestion of a high-energy meal after fasting for 12h. From the data of this study, we propose a consistent estimation of patient-specific 3D cardiac electromechanical models at two different instants of the protocol (pre-ingestion and t+1h).…”

Impact of sequence type and field strength (1.5, 3, and 7T) on 4D flow MRI hemodynamic aortic parameters in healthy volunteers

“…The differences between 4D flow at different field strengths could also be caused by physiological changes of hemodynamics and/or fluid or food intake 45 of the individual volunteer, as our volunteers did not fast before conducting the scan. However, all scans were performed at approximately the same time of day resulting in a probable similar food influence on hemodynamics.…”

Longitudinal Analysis Using Personalised 3D Cardiac Models with Population-Based Priors: Application to Paediatric Cardiomyopathies

“…The two protocols were approved by the local Research Ethics Committees. First 22 volunteers (C1) who participated to a clinical study to assess the cardiovascular response after the ingestion of a high-energy (1635 kcal), high-fat (142g) meal after fasting for 12h, closely following the protocol in [3]. In this study, short axis cardiac cine MRI sequences were acquired before the ingestion and at one or more time points within 1h of the ingestion of the meal, in order to study the evolution of the blood flow in the arteries.…”