Understanding exercise-induced hyperemia: central and peripheral hemodynamic responses to passive limb movement in heart transplant recipients

作者：Hayman Melissa A; Nativi Jose N; Stehlik Josef; McDaniel John; Fjeldstad Anette S; Ives Stephen J; Wray D Walter; Bader Feras; Gilbert Edward M; Richardson Russell S^*

来源：American Journal of Physiology - Heart and Circulatory Physiology, 2010, 299(5): H1653-H1659.

DOI：10.1152/ajpheart.00580.2010

• blood flow
• skeletal muscle

Hayman MA, Nativi JN, Stehlik J, McDaniel J, Fjeldstad AS, Ives SJ, Wray DW, Bader F, Gilbert EM, Richardson RS. Understanding exercise-induced hyperemia: central and peripheral hemodynamic responses to passive limb movement in heart transplant recipients. Am J Physiol Heart Circ Physiol 299: H1653-H1659, 2010. First published September 10, 2010; doi:10.1152/ajpheart.00580.2010.-To better characterize the contribution of both central and peripheral mechanisms to passive limb movement-induced hyperemia, we studied nine recent (<2 yr) heart transplant (HTx) recipients (56 +/- 4 yr) and nine healthy controls (58 +/- 5 yr). Measurements of heart rate (HR), stroke volume (SV), cardiac output (CO), and femoral artery blood flow were recorded during passive knee extension. Peripheral vascular function was assessed using brachial artery flow-mediated dilation (FMD). During passive limb movement, the HTx recipients lacked an HR response (0 +/- 0 beats/min, Delta 0%) but displayed a significant increase in CO (0.4 +/- 0.1 l/min, Delta 5%) although attenuated compared with controls (1.0 +/- 0.2 l/min, Delta 18%). Therefore, the rise in CO in the HTx recipients was solely dependent on increased SV (5 +/- 1 ml, Delta 5%) in contrast with the controls who displayed significant increases in both HR (6 +/- 2 beats/min, Delta 11%) and SV (5 +/- 2 ml, Delta 7%). The transient increase in femoral blood volume entering the leg during the first 40 s of passive movement was attenuated in the HTx recipients (24 +/- 8 ml) compared with controls (93 +/- 7 ml), whereas peripheral vascular FMD) appeared similar between HTx recipients (8 +/- 2%) and controls (6 +/- 1%). These data reveal that the absence of an HR increase in HTx recipients significantly impacts the peripheral vascular response to passive movement in this population and supports the concept that an increase in CO is a major contributor to exercise-induced hyperemia.

• 出版日期2010-11