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The Effect of Left Ventricular‐Central Artery Coupling on Cerebrovascular Hemodynamics: Insights from Lower Body Negative Pressure
Author(s) -
Tomoto Tsubasa,
Imai Tomoko,
Ogoh Shigehiko,
Maeda Seiji,
Sugawara Jun
Publication year - 2016
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.30.1_supplement.1203.2
Subject(s) - supine position , pulsatile flow , cardiology , medicine , hemodynamics , stroke volume , venous return curve , cerebral blood flow , middle cerebral artery , blood pressure , anesthesia , heart rate , ischemia
Substantial pulsatile fluctuation of cerebral blood flow is an adverse impact on vulnerable brain tissue. Since endurance‐trained athlete exhibits left ventricular eccentric remodeling, the transient increase in venous return may result in substantial increase in stroke volume (SV), which cause of increase in pulsatile flow fluctuation. The aim of this study was to test the hypothesis that, in endurance‐trained, substantial increase in SV does not cause augmented pulsatile fluctuation of cerebral blood flow because of high aortic buffering function. Endurance‐trained (ET, n =10) and age‐matched sedentary (SED, n =10) young healthy men underwent lower body negative pressure (LBNP) (−30 mmHg for 4 minutes) stimulation and release that initiated an acute increase in venous return and consequently increased in SV. The hemodynamic response was evaluated following release of LBNP up to 15 seconds. SV (via Modeflow method) and pulsatility index of middle cerebral arterial blood flow velocity (PI MCA V , via transcranial Doppler) significantly increased after release of LBNP in both groups. The increase in SV was significantly greater in ET than in SED (P<0.01), whereas there was no group‐difference in responses of PI MCA V . SV/PP, an index of aortic buffering function, was significantly higher at rest in ET compared with SED. Furthermore, after the LBNP release SV/PP significantly elevated in ET but not in SED. These results suggest that acute postural change from standing to supine position greatly increases SV in ET; however, substantial augmentation of cerebral pulsatile fluctuation does not occur. This phenomenon might be associated with superior aortic buffering function in ET.