Impacts of dietary nitrate on endothelial function, arterial stiffness, and systemic vascular pressure in peripheral arterial disease

Peripheral arterial disease (PAD) is the manifestation of atherosclerotic plaque in the larger arteries of the legs, which results in impaired blood flow to the lower extremities. Markers of vascular health, including endothelial function and arterial stiffness, have been shown to be attenuated in PAD. Purpose: We sought to examine the effects of a nitrate supplement (body mass-normalized dosage of beetroot juice) on vascular function measurements such as endothelial function, arterial stiffness, and central and peripheral blood pressure in patients with PAD. We hypothesized that acute intake of a nitrate supplement would improve vascular function. Methods: PAD patients (stage II-III, n=2, age around 73) had vascular measurements taken pre and post-beetroot juice ingestion including heart rate (HR), blood pressure (BP), endothelial function, arterial stiffness, and central pressure analysis. Results: Following nitrate ingestion, HR increased (Δ0.5 bpm) along with decreases in peripheral BP (Δ-9/-10 mmHg) and central BP (Δ-18/-4 mmHg). Endothelial function increased (Δ3.75%), carotid-to-radial pulse wave velocity decreased (Δ0.25 m/s), and augmentation index increased (Δ30.1%) after nitrate intake. Measurements of deceleration time increased (Δ49.5ms) and augmented pressure decreased (Δ-5 mmHg) after nitrate ingestion. Conclusion: Acute intake of a nitrate supplement may potentially be a useful therapeutic treatment to improve both central and peripheral vascular function which may be explained by increased endothelial dependent and independent vasodilatory mechanisms. However, this is a pilot study with two patients; therefore, future study is warranted with a bigger sample size to examine impacts of nitrate ingestion on vascular function and to further extrapolate our findings to patients with PAD