Renal vasoconstriction is augmented during exercise in patients with peripheral arterial disease

Abstract

Peripheral arterial disease (PAD) patients have augmented blood pressure increases during exercise, heightening their cardiovascular risk. However, it is unknown whether patients have exaggerated renal vasoconstriction during exercise and if oxidative stress contributes to this response. Eleven PAD patients and 10 controls (CON) performed 4-min mild, rhythmic, plantar flexion exercise of increasing intensity (0.5–2 kg) with each leg (most and least affected in PAD). Eight patients also exercised with their most affected leg during ascorbic acid (AA) infusion. Renal blood flow velocity (RBFV; Doppler ultrasound), mean arterial blood pressure (MAP; Finometer), and heart rate (HR; electrocardiogram [ECG]) were measured. Renal vascular resistance (RVR), an index of renal vasoconstriction, was calculated as MAP/RBFV. Baseline RVR and MAP were similar while HR was higher in PAD than CON (2.08 ± 0.23 vs. 1.87 ± 0.20 au, 94 ± 3 vs. 93 ± 3 mmHg, and 72 ± 3 vs. 59 ± 3 bpm [P < 0.05] for PAD and CON, respectively). PAD had greater RVR increases during exercise than CON, specifically during the first minute (PAD most: 26 ± 5% and PAD least: 17 ± 5% vs. CON: 3 ± 3%; P < 0.05). AA did not alter baseline RVR, MAP, or HR. AA attenuated the augmented RVR increase in PAD during the first minute of exercise (PAD most: 33 ± 4% vs. PAD most with AA: 21 ± 4%; P < 0.05). In conclusion, these findings suggest that PAD patients have augmented renal vasoconstriction during exercise, with oxidative stress contributing to this response.

Inhibition of cyclooxygenase attenuates the blood pressure response to plantar flexion exercise in peripheral arterial disease

“…After a 15-min quiet rest period, baseline BPs were obtained via automated oscillometry of the brachial artery (Philips SureSigns Vs3), and a blood sample was obtained for the measurement of thromboxane B 2 (stable marker of thromboxane A2) and 6-keto-PGF1␣ (stable marker of prostacyclin, Penn State Core Endocrine Laboratory, Hershey, PA). The calf of the supine volunteer was supported by cushions to assure a full range of motion (i.e., active plantar flexion), and a custom sandal was affixed to the foot, consistent with previous studies in our laboratory (13,28).…”

“…The standard of care Rating of perceived exertion 0.5 kg 7 (6-9) 6 (6-9) 6 (6-7) 6 (6-7) 1.0 kg 9 (6-11) 8 (6-10) 7 (6-9) 7 (6-7) 1.5 kg 10 (8-13) 9 (8-13)* 8 (6-11) 7 (6-9) 2.0 kg 11 (9)(10)(11)(12)(13)(14) 10 (9-14)* 9 (7-12) 9 (7-10) 7.0 kg 15 (13)(14)(15)(16)(17) Data are shown as medians with ranges in parentheses; n ϭ 7 PAD patients and 7 healthy control subjects. *Significant difference between groups at the specific time point.…”

“…In recent years, our laboratory has focused on BP control in patients with PAD. Specifically, we found that 1) the BP response to single-leg dynamic plantar flexion exercise was augmented in PAD patients compared with healthy control subjects; 2) the pressor response occurred at very low workloads and before the onset of pain; 3) the pressor response correlated with the anklebrachial index (ABI), suggesting that disease severity plays a role; and 4) intravenous infusion of ascorbic acid lowered the pressor response to exercise in PAD (13,28). To date, the mechanisms for these findings are largely unknown.…”

Chronic femoral artery ligation exaggerates the pressor and sympathetic nerve responses during dynamic skeletal muscle stretch in decerebrate rats

“…Regardless of whether an individual with PAD presents with intermittent claudication they are still subject to an increased risk of myocardial infarction, stroke, and allcause mortality (19,41). Compared to age-matched healthy subjects, exercise in PAD patients has been shown to elicit exaggerated increases in sympathetic nerve activity (SNA) and blood pressure (5,7,8,15,28). In PAD patients, large increases in blood pressure during treadmill walking have been linked to an increased risk of a major ischemic event and all-cause mortality (14).…”

Chronic kidney disease and sports participation by children and adolescents

“…Renal blood flow (RBF) reduces during exercise with the magnitude of decrease directly proportional to the intensity of physical activity (16)(17)(18)(19). The degree of intravascular hydration can affect the changes in RBF with more decline noted in a dehydrated state when compared to an initial hyper hydrated status (20)(21)(22).…”