The effect of L-arginine and citrulline on endothelial function in patients in heart failure with preserved ejection fraction.

BACKGROUND To evaluate the effect of the amino acids L-arginine and citrulline on endothelial function in patients in stable diastolic and right heart failure using photoplethysmography. METHODS Thirty patients from the Heart Failure Clinic of the Instituto Nacional de Ciencias Médicas y Nutrición "Salvador Zubirán" underwent photoplethysmography using the hyperemia technique. Index finger flow was assessed at baseline and after ischemia every 30 s by maximum amplitude time (MAT), total time of the curve (TT) and the index of the two (MAT/TT < 30 = normal) before and after the administration of L-arginine (8 g/day in two doses, n = 15) or citrulline (3 g/day in one dose, n = 15) for 60 days in addition to optimal pharmacological treatment. RESULTS There were no statistically significant differences between the two groups at baseline. After the intervention, the MAT/TT index of all patients normalized in each evaluation period with statistically significant differences. Basal L-arginine group = 38.75 ± 11.52, final 23.32 ± 6.08, p = 0.007 and basal citrulline group = 41.4 ± 13.47, final 23.65 ± 6.74, p = 0.007 at 60-90 s. Post-ischemia: basal L-arginine 36.60 ± 11.51, final 18.81 ± 15.13, p = 0.004 and basal citrulline = 49.51 ± 15.17, final 27.13 ± 7.87, p = 0.003. CONCLUSIONS The administration of L-arginine and citrulline has a beneficial effect on endothelial function as shown by the normalized MAT/TT index. It probably improves systemic and pulmonary hemodynamics, which could help in the treatment of diastolic heart failure.