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.

Purpose: Consumption of nitrate-rich beetroot juice can lower blood pressure in peripheral as well as central arteries and may exert additional hemodynamic benefits (e.g. reduced aortic wave reflections). The specific influence of nitrate supplementation on arterial pressures and aortic wave properties in postmenopausal women, a group that experiences accelerated increases in these variables with age, is unknown. Accordingly, the primary aim of this study was to determine the effect of consuming nitrate-rich beetroot juice on resting brachial and aortic blood pressures (BP)

Patients with peripheral arterial disease (PAD) have an accentuated exercise pressor reflex (EPR). The underlying hemodynamic changes responsible for the exaggerated EPR, and the effect of this on blood flow to the exercising limb is unclear. We tested the hypothesis that the exaggerated EPR in PAD is mediated by an increase in total peripheral resistance (TPR), which augments redistribution of blood flow to the ischemic exercising muscle. METHODS Eleven PAD patients and 11 age, and sex‐matched subjects without PAD (control) performed dynamic plantar flexion (PF) using their symptomatic leg at progressive workloads of 2 to 12 kg (increased by 1 kg/min until the onset of fatigue). We measured heart rate (HR), beat‐by‐beat blood pressure (BP), femoral blood flow velocity (FBV), and near‐infrared spectroscopy derived tissue oxygen saturation (SmO2) continuously during the exercise. Femoral blood flow (FBF) was calculated from FBV and baseline femoral artery diameter. Stroke volume (SV), cardiac output (CO), and TPR were derived from the BP tracings. RESULTS Mean arterial blood pressure (MAP) was significantly augmented in PAD compared to controls during PF (P < 0.001). This was accompanied by an equal rise in CO in the two groups. Of note, TPR decreased in controls, whereas it increased in PAD. The increase in femoral blood flow velocity was greater during exercise in PAD as compared to controls (P = 0.0021), however, the increased FBF in the two groups was the same. Despite the fact the flow was not different between PAD and control group, SmO2 of the exercising limb remained significantly lower in PAD compared to control (P < 0.001). CONCLUSION We conclude that the exaggerated pressor response in PAD is mediated by an abnormal response in TPR, which augments redistribution of blood flow to the exercising muscle, leading to an equal rise in FBF compared to controls. However, this increase in FBF is not sufficient to normalize the SmO2 response during exercise in patients with PAD. Support or Funding Information Supported by National Institutes of Health Grants P01 HL134609 (Sinoway) and UL1 TR002014 (Sinoway). This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

We determined whether a greater exercise pressor response during a constant-load treadmill test was associated with lower peak walking time (PWT) and claudication onset time (COT) measured during a graded maximal treadmill test in 304 patients with symptomatic peripheral artery disease (PAD). The exercise pressor response was assessed by measuring heart rate and blood pressure (BP) at rest and during a constant-load treadmill test (speed = 2 mph, grade = 0%). After only 2 minutes of walking, mean heart rate increased by 26 beats/min from rest and mean systolic BP increased by 16 mm Hg. In adjusted analyses, increases in systolic BP ( P = .021), heart rate ( P = .002), mean arterial pressure ( P = .034), and rate–pressure product ( P < .001) from rest to 2 minutes of constant-load exercise were negatively associated with COT. Similarly, increases in heart rate ( P = .012) and rate–pressure product ( P = .018) from rest to 2 minutes of constant-load exercise were negatively associated with PWT. A greater exercise pressor response observed after only 2 minutes of walking at no incline was independently associated with impaired claudication outcomes in patients with symptomatic PAD. The implication is that the exercise pressor response is an important and easily obtained clinical measurement that partially explains differences in PWT and COT.