The aims of this work were (1) to compare cerebral oxy
g enation-perfusion (COP), central hemodynamics, and peak oxy
g en uptake (
g" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0828282X15005395&_mathId=si1.g if&_user=111111111&_pii=S0828282X15005395&_rdoc=1&_issn=0828282X&md5=cbdd71d37d78470164b71aa9313ae50c">g class="img LazyJSB inlineImag e" heig ht="14" width="12" alt="View the MathML source" style="marg in-top: -5px; vertical-alig n: middle" title="View the MathML source" src="/sd/g rey_pxl.g if" data-inlimg eid="1-s2.0-S0828282X15005395-si1.g if">g heig ht="14" border="0" style="vertical-alig n:bottom" width="12" alt="View the MathML source" title="View the MathML source" src="http://orig in-ars.els-cdn.com/content/imag e/1-s2.0-S0828282X15005395-si1.g if"> g="si1.g if" overflow="scroll">V ˙ o 2 peak) in heart transplant recipients (HTRs) vs a
g e-matched healthy controls (AMHCs) durin
g exercise and recovery and (2) to study the relationships between COP, central hemodynamics, and
g" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0828282X15005395&_mathId=si1.g if&_user=111111111&_pii=S0828282X15005395&_rdoc=1&_issn=0828282X&md5=cbdd71d37d78470164b71aa9313ae50c">g class="img LazyJSB inlineImag e" heig ht="14" width="12" alt="View the MathML source" style="marg in-top: -5px; vertical-alig n: middle" title="View the MathML source" src="/sd/g rey_pxl.g if" data-inlimg eid="1-s2.0-S0828282X15005395-si1.g if">g heig ht="14" border="0" style="vertical-alig n:bottom" width="12" alt="View the MathML source" title="View the MathML source" src="http://orig in-ars.els-cdn.com/content/imag e/1-s2.0-S0828282X15005395-si1.g if"> g="si1.g if" overflow="scroll">V ˙ o 2 peak in HTRs and AMHCs.
Methods Twenty-six HTRs (3 women) and 27 AMHCs (5 women) were recruited. Maximal cardiopulmonary function (g as exchang e analysis), cardiac hemodynamics (impedance cardiog raphy), and left frontal COP (near-infrared spectroscopy) were measured continuously during and after a maximal erg ocycle (Erg oline 800S, Bitz, Germany) test.
Results Compared with AMHCs, HTRs had lower g" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0828282X15005395&_mathId=si1.g if&_user=111111111&_pii=S0828282X15005395&_rdoc=1&_issn=0828282X&md5=cbdd71d37d78470164b71aa9313ae50c">g class="img LazyJSB inlineImag e" heig ht="14" width="12" alt="View the MathML source" style="marg in-top: -5px; vertical-alig n: middle" title="View the MathML source" src="/sd/g rey_pxl.g if" data-inlimg eid="1-s2.0-S0828282X15005395-si1.g if">g heig ht="14" border="0" style="vertical-alig n:bottom" width="12" alt="View the MathML source" title="View the MathML source" src="http://orig in-ars.els-cdn.com/content/imag e/1-s2.0-S0828282X15005395-si1.g if"> g="si1.g if" overflow="scroll">V ˙ o 2 peak, maximal cardiac index (CImax), and maximal ventilatory variables (P < 0.05). COP was lower during exercise (oxyhemog lobin [ΔO2 Hb], 50% and 75% of g" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0828282X15005395&_mathId=si1.g if&_user=111111111&_pii=S0828282X15005395&_rdoc=1&_issn=0828282X&md5=cbdd71d37d78470164b71aa9313ae50c">g class="img LazyJSB inlineImag e" heig ht="14" width="12" alt="View the MathML source" style="marg in-top: -5px; vertical-alig n: middle" title="View the MathML source" src="/sd/g rey_pxl.g if" data-inlimg eid="1-s2.0-S0828282X15005395-si1.g if">g heig ht="14" border="0" style="vertical-alig n:bottom" width="12" alt="View the MathML source" title="View the MathML source" src="http://orig in-ars.els-cdn.com/content/imag e/1-s2.0-S0828282X15005395-si1.g if"> g="si1.g if" overflow="scroll">V ˙ O 2 peak, total hemog lobin [ΔtHb], 100% of g" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0828282X15005395&_mathId=si1.g if&_user=111111111&_pii=S0828282X15005395&_rdoc=1&_issn=0828282X&md5=cbdd71d37d78470164b71aa9313ae50c">g class="img LazyJSB inlineImag e" heig ht="14" width="12" alt="View the MathML source" style="marg in-top: -5px; vertical-alig n: middle" title="View the MathML source" src="/sd/g rey_pxl.g if" data-inlimg eid="1-s2.0-S0828282X15005395-si1.g if">g heig ht="14" border="0" style="vertical-alig n:bottom" width="12" alt="View the MathML source" title="View the MathML source" src="http://orig in-ars.els-cdn.com/content/imag e/1-s2.0-S0828282X15005395-si1.g if"> g="si1.g if" overflow="scroll">V ˙ O 2 peak; P < 0.05), and recovery in HTRs (ΔO2 Hb, minutes 2-5; ΔtHb, minutes 1-5; P < 0.05) compared with AMHCs. End-tidal pressure of CO2 was lower during exercise compared with that in AMHCs (P < 0.0001). In HTRs, CImax was positively correlated with exercise cerebral hemodynamics (R = 0.54-0.60; P < 0.01).
Conclusions In HTRs, COP was reduced during exercise and recovery compared with that in AMHCs, potentially because of a combination of blunted cerebral vasodilation by CO2 , cerebrovascular dysfunction, reduced cardiac function, and medication. The impaired g" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0828282X15005395&_mathId=si1.g if&_user=111111111&_pii=S0828282X15005395&_rdoc=1&_issn=0828282X&md5=cbdd71d37d78470164b71aa9313ae50c">g class="img LazyJSB inlineImag e" heig ht="14" width="12" alt="View the MathML source" style="marg in-top: -5px; vertical-alig n: middle" title="View the MathML source" src="/sd/g rey_pxl.g if" data-inlimg eid="1-s2.0-S0828282X15005395-si1.g if">g heig ht="14" border="0" style="vertical-alig n:bottom" width="12" alt="View the MathML source" title="View the MathML source" src="http://orig in-ars.els-cdn.com/content/imag e/1-s2.0-S0828282X15005395-si1.g if"> g="si1.g if" overflow="scroll">V ˙ O 2 peak observed in HTRs was mainly caused by reduced maximal ventilation and CI. In HTRs, COP is impaired and is correlated with cardiac function, potentially impacting cog nitive function. Therefore, we need to study which interventions (eg , exercise training ) are most effective for improving or normalizing (or both) COP during and after exercise in HTRs.
