Blood pressure and leg deoxygenation are exaggerated during treadmill walking in patients with peripheral artery disease

Abstract

The purpose of this study was to investigate blood pressure (BP) and leg skeletal muscle oxygen saturation (Smo) during treadmill walking in patients with peripheral artery disease (PAD) and healthy subjects. Eight PAD patients (66 ± 8 yr, 1 woman) and eight healthy subjects (65 ± 7 yr, 1 woman) walked on a treadmill at 2 mph (0.89 m/s). The incline increased by 2% every 2 min, from 0 to 15% or until maximal discomfort. BP was measured every 2 min with an auscultatory cuff. Heart rate (HR) was recorded continuously with an ECG. Smo in the gastrocnemius muscle was measured on each leg using near-infrared spectroscopy. The change in systolic BP from seated to peak walking time (PWT) was greater in PAD (healthy: 23 ± 9 vs. PAD: 44 ± 19 mmHg, = 0.007). HR was greater in PAD patients compared with controls at PWT ( = 0.011). The reduction in Smo (PWT - seated) was greater in PAD (healthy: 15 ± 12 vs. PAD: 49 ± 5%, < 0.001) in the most affected leg and in the least affected leg (healthy: 12 ± 11 vs. PAD: 32 ± 18%, = 0.003). PAD patients have an exaggerated decline in leg Smo during walking compared with healthy subjects, which may elicit the exaggerated rise in BP and HR during walking in PAD. This is the first study to simultaneously measure skeletal muscle oxygen saturation and blood pressure (BP) during treadmill exercise in patients with peripheral arterial disease. We found that BP and leg deoxygenation responses to slow-paced, graded treadmill walking are greater in patients with peripheral arterial disease compared with healthy subjects. These data may help explain the high cardiovascular risk in patients with peripheral arterial disease.

Acute effects of leg heat therapy on walking performance and cardiovascular and inflammatory responses to exercise in patients with peripheral artery disease

“…The pillars of the medical management of PAD are to reduce cardiovascular morbidity and mortality and to reduce limb morbidity (Bonaca & Creager, 2015). Our current findings, as well as other recent studies (Akerman et al, 2019;Kim et al, 2017;Monroe et al, 2020;Pellinger et al, 2019), indicate that HT may be a practical adjunctive therapy that fulfills both therapeutic goals. First, by reducing resting and exercise BP as well as the circulating levels of ET-1, HT may improve cardiovascular health and consequently diminish the risk of MI, stroke, and death in patients with PAD.…”

“…First, by reducing resting and exercise BP as well as the circulating levels of ET-1, HT may improve cardiovascular health and consequently diminish the risk of MI, stroke, and death in patients with PAD. Second, by enhancing leg blood flow (Neff et al, 2016;Thomas et al, 2017) and improving muscle mass and strength (Kim et al, 2017), among other factors, HT may alleviate the leg symptoms and enhance the functional capacity of PAD patients. Third, by improving walking tolerance in some patients, leg HT may boost the adaptations to regular exercise.…”

A systematic review of diagnostic techniques to determine tissue perfusion in patients with peripheral arterial disease

“…NIRS is also limited by tissue infection and inflammation. Furthermore, outcome values of NIRS are sensitive to both oxygen delivery and oxygen extraction [30]. In PAD, using contact-free methods, such as HSI, LSCI, or MRI, may be preferable, especially when patients have foot ulcers.…”

“…Miller et al [30] included eight patients with PAD and eight healthy controls. PAD was assessed by an ABI <0.9, and all patients were classified as Fontaine 2.…”

The exercise pressor reflex and active O 2 transport in peripheral arterial disease

“…However, despite slower onset kinetics, the magnitude of skeletal muscle desaturation is augmented during graded submaximal and fatiguing work in PAD (Luck et al, ). This indicates that O 2 utilization increases relative to O 2 supply, reflecting an elevated metabolic perturbation which likely contributes to the exaggerated exercise pressor reflex observed in these patients (Miller et al, ; Muller et al, ; Ross et al, ).…”