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

Meneses, Annelise L., Nam, Michael C.Y., Bailey, Tom G., Magee, Rebecca, Golledge, Jonathan, Hellsten, Ylva, Keske, Michelle A., Greaves, Kim, and Askew, Christopher D. (2018) Leg blood flow and skeletal muscle microvascular perfusion responses to submaximal exercise in peripheral arterial disease. American Journal of Physiology-Heart and Circulatory Physiology, 315 (5). H1425-H1433.

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Abstract

Peripheral arterial disease (PAD) is characterized by stenosis and occlusion of the lower limb arteries. Although 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 after cuff occlusion and submaximal leg exercise between patients with PAD (n = 12, 69 ± 9 yr) and healthy age-matched control participants (n = 12, 68 ± 7 yr). Microvascular blood flow (microvascular volume × flow velocity) of the medial gastrocnemius muscle was measured before and immediately after the following: 1) 5 min of thigh-cuff occlusion, and 2) a 5-min bout of intermittent isometric plantar-flexion exercise (400 N) using real-time contrast-enhanced ultrasound. Whole leg blood flow was measured after thigh-cuff occlusion and during submaximal plantar-flexion exercise using strain-gauge plethysmography. Postocclusion whole leg blood flow and calf muscle microvascular perfusion were lower in patients with PAD than control participants, 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 postexercise calf muscle microvascular perfusion, although microvascular blood volume was higher in patients with PAD than control participants (12.41 ± 6.98 vs. 6.34 ± 4.98 arbitrary units, P = 0.03). This study demonstrates that the impaired muscle perfusion of patients with PAD during postocclusion 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 patients with PAD, which may reflect a compensatory mechanism to maintain muscle perfusion and oxygen delivery during recovery from exercise.

NEW & NOTEWORTHY: This study suggests that peripheral arterial disease (PAD) has different effects on the microvascular perfusion responses to cuff occlusion and submaximal leg exercise. Patients with PAD have impaired microvascular perfusion after cuff occlusion, similar to that previously reported after maximal exercise. In response to submaximal exercise, however, the microvascular flow volume response was elevated in patients with PAD compared with control. This finding may reflect a compensatory mechanism to maintain perfusion and oxygen delivery during recovery from exercise.

Item ID: 56749
Item Type: Article (Research - C1)
ISSN: 1522-1539
Keywords: exercise, microcirculation, peripheral arterial disease, reactive hyperemia, skeletal muscle, ultrasound
Funders: National Health and Medical Research Council (NHMRC)
Projects and Grants: NHMRC grant 1063476, NHMRC grant 1000967, NHMRC practitioner fellowship 1117061
Date Deposited: 02 Jan 2019 07:31
FoR Codes: 11 MEDICAL AND HEALTH SCIENCES > 1102 Cardiovascular Medicine and Haematology > 110299 Cardiovascular Medicine and Haematology not elsewhere classified @ 100%
SEO Codes: 92 HEALTH > 9201 Clinical Health (Organs, Diseases and Abnormal Conditions) > 920199 Clinical Health (Organs, Diseases and Abnormal Conditions) not elsewhere classified @ 100%
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