TY - JOUR

T1 - Leg blood flow and skeletal muscle microvascular perfusion responses to submaximal exercise in peripheral arterial disease

AU - Meneses, Annelise L

AU - Nam, Michael C Y

AU - Bailey, Tom G

AU - Magee, Rebecca

AU - Golledge, Jonathan

AU - Hellsten, Ylva

AU - Keske, Michelle A

AU - Greaves, Kim

AU - Askew, Christopher D

N1 - CURIS 2018 NEXS 371

PY - 2018

Y1 - 2018

N2 - Peripheral arterial disease (PAD) is characterized by stenosis and occlusion of the lower limb arteries. While leg blood flow is limited in PAD, it remains unclear whether skeletal muscle microvascular perfusion is affected. We compared whole-leg blood flow and calf muscle microvascular perfusion following cuff occlusion and submaximal leg exercise between PAD patients (n=12, 69±9 years) and healthy age-matched control participants (n=12, 68±7 years). Microvascular blood flow (microvascular volume x flow velocity) of the medial gastrocnemius muscle was measured before and immediately after: 1) 5 min of thigh-cuff occlusion; and 2) a 5-min bout of intermittent isometric plantar-flexion exercise (400N) using real-time contrast-enhanced ultrasound (CEU). Whole-leg blood flow was measured after thigh-cuff occlusion and during submaximal plantar-flexion exercise using strain-gauge plethysmography. Post-occlusion whole-leg blood flow and calf muscle microvascular perfusion were lower in PAD patients than controls, and these parameters were strongly correlated (r=0.84; p<0.01). During submaximal exercise, total whole-leg blood flow and vascular conductance were not different between groups. There were also no group differences in post-exercise calf muscle microvascular perfusion, although microvascular blood volume was higher in PAD patients than control (12.41±6.98 vs 6.34±4.98 aU; p=0.03). This study demonstrates that the impaired muscle perfusion of PAD patients during post-occlusion hyperemia is strongly correlated with disease severity, and is likely mainly determined by the limited conduit artery flow. In response to submaximal leg exercise, microvascular flow volume was elevated in PAD patients, which may reflect a compensatory mechanism to maintain muscle perfusion and oxygen delivery during recovery from exercise.

AB - Peripheral arterial disease (PAD) is characterized by stenosis and occlusion of the lower limb arteries. While leg blood flow is limited in PAD, it remains unclear whether skeletal muscle microvascular perfusion is affected. We compared whole-leg blood flow and calf muscle microvascular perfusion following cuff occlusion and submaximal leg exercise between PAD patients (n=12, 69±9 years) and healthy age-matched control participants (n=12, 68±7 years). Microvascular blood flow (microvascular volume x flow velocity) of the medial gastrocnemius muscle was measured before and immediately after: 1) 5 min of thigh-cuff occlusion; and 2) a 5-min bout of intermittent isometric plantar-flexion exercise (400N) using real-time contrast-enhanced ultrasound (CEU). Whole-leg blood flow was measured after thigh-cuff occlusion and during submaximal plantar-flexion exercise using strain-gauge plethysmography. Post-occlusion whole-leg blood flow and calf muscle microvascular perfusion were lower in PAD patients than controls, and these parameters were strongly correlated (r=0.84; p<0.01). During submaximal exercise, total whole-leg blood flow and vascular conductance were not different between groups. There were also no group differences in post-exercise calf muscle microvascular perfusion, although microvascular blood volume was higher in PAD patients than control (12.41±6.98 vs 6.34±4.98 aU; p=0.03). This study demonstrates that the impaired muscle perfusion of PAD patients during post-occlusion hyperemia is strongly correlated with disease severity, and is likely mainly determined by the limited conduit artery flow. In response to submaximal leg exercise, microvascular flow volume was elevated in PAD patients, which may reflect a compensatory mechanism to maintain muscle perfusion and oxygen delivery during recovery from exercise.

KW - Faculty of Science

KW - Peripheral arterial disease

KW - Skeletal muscle

KW - Microcirculation

KW - Reactive hyperemia

KW - Exercise

KW - Ultrasound

U2 - 10.1152/ajpheart.00232.2018

DO - 10.1152/ajpheart.00232.2018

M3 - Journal article

C2 - 30095999

VL - 315

SP - H1425-H1433

JO - American Journal of Physiology: Heart and Circulatory Physiology

JF - American Journal of Physiology: Heart and Circulatory Physiology

SN - 0363-6135

IS - 5

ER -