Inorganic nitrate supplementation may improve diastolic function and the O 2 cost of exercise in cancer survivors: a pilot study.

In non-cancer populations, inorganic dietary nitrate (NO 3 - ) supplementation is associated with enhanced cardiorespiratory function but remains untested in patients with a history of cancer. Therefore, this pilot study sought to determine if oral NO 3 - supplementation, as a supportive care strategy, increases left ventricular (LV) function and exercise performance in survivors of cancer treated with anticancer therapy while simultaneously evaluating the feasibility of the methods and procedures required for future large-scale randomized trials. Two cohorts of patients with a history of cancer treated with anticancer chemotherapy were recruited. Patients in cohort 1 (n = 7) completed a randomized, double-blind, crossover study with 7 days of NO 3 - or placebo (PL) supplementation, with echocardiography. Similarly, patients in cohort 2 (n = 6) received a single, acute dose of NO 3 - supplementation or PL. Pulmonary oxygen uptake (VO 2 ), arterial blood pressure, and stroke volume were assessed during exercise. In cohort 1, NO 3 - improved LV strain rate in early filling (mean difference (MD) [95% CI]: - 0.3 1/s [- 0.6 to 0.06]; P = 0.04) and early mitral septal wall annular velocity (MD [95% CI]: 0.1 m/s [- 0.01 to - 0.001]; P = 0.02) compared to placebo. In cohort 2, NO 3 - decreased the O 2 cost of low-intensity steady-state exercise (MD [95% CI]: - 0.5 ml/kg/min [- 0.9 to - 0.09]; P = 0.01). Resting and steady-state arterial blood pressure and stroke volume were not different between conditions. No differences between conditions for peak VO 2 (MD [95% CI]: - 0.7 ml/kg/min [- 3.0 to 1.6]; P = 0.23) were observed. The findings from this pilot study warrant further investigation in larger clinical trials targeting the use of long-term inorganic dietary NO 3 - supplementation as a possible integrative supportive care strategy in patients following anticancer therapy.