Effect of Dietary Nitrate Supplementation on Blood Pressure Variability and Vascular Function in High-Risk Transient Ischemic Attack Patients

Background: Patients presenting with a transient ischemic attack (TIA) are at high risk of stroke despite current treatments. Elevated blood pressure variability (BPV) and vascular dysfunction are known to increase the risk of stroke in TIA patients. Therefore, improving these hemodynamic parameters could help reduce stroke incidences in these patients. Aim: The proposed study will investigate the efficacy of dietary nitrate supplementation on cardiovascular and cerebrovascular hemodynamics in patients recently diagnosed with TIA. Methods: This study is a randomized, placebo-controlled, parallel group clinical trial, with patient recruitment based on strict inclusion/exclusion criteria. Newly diagnosed patients who present within 48 h of symptom onset will be assessed to ascertain their post-TIA, pre-treatment baseline cardiovascular and cerebrovascular parameters. These will include: beat-to-beat BPV, cerebrovascular CO2 reactivity and cerebral autoregulation (indices of cerebrovascular health), brachial artery diameter, central and peripheral blood pressures, vascular risk factors (i.e. resting blood pressure), and plasma nitrate/nitrite concentration. Following pre-treatment assessment, participants will be randomized to take either 7-day dietary nitrate supplementation (sodium nitrate in capsules, 10 mg/kg/day) or 7-day placebo. An identical follow-up assessment will be implemented post-intervention. Conclusion: This study will lay the foundation for clinical trials to assess the therapeutic potential of dietary nitrate supplementation as a secondary strategy for stroke prevention in high-risk patients.