Disfunção vasodilatadora durante o estresse mental em pacientes com doença renal crônica

Abstract

INTRODUCTION: Previous researches demonstrated that patients with chronic kidney disease have exaggerated blood pressure response during mental stress. However, it is not known how the vasodilatation dysfunction could influence these hemodinamic abnormalities. Therefore, the aim of this study was to test the hypotesis that patients with chronic kidney disease would have vasodiltation dysfunction during mental stress. MATERIALS AND METHODS: Nine patients with chronic kidney disease and twelve healthy individuals matched by age (41 ± 5 vs. 35 ± 5 years, p=0.36, respectively) were studied. The mental stress was induced by Stroop Color Word Conflict Test. The blood pressure (oscillometric method - DIXTAL® 2023), heart rate (electrocardiogram - DIXTAL® 2023) and forearm blood flow (venous occlusion pletysmogrphy - Hokanson®) were recorded simultaneously during baseline for 3 minutes followed by 3 minutes of Mental Stress. The vascular conductance was calculated by the division of forearm blood flow by mean blood pressure. RESULTS: At baseline conditions the patients with chronic kidney have shown higher levels of blood pressure than healthy individuals. Both groups increased blood pressure significantly (time effect; p<0.01) and similarly (interaction effect; p=0.51) during mental stress, however, patients with chronic kidney disease maintained increased levels during entire protocol (group effect; p<0.04). Although resembling at basal condition (p=0.26), the blood flow increased differently between groups (interaction effect; p<0.01), which patients reached lower levels than healthy individuals (group effect; p<0.04) during whole mental stress protocol. Moreover, the patients with chronic kidney disease did not show vascular conductance changes (p>0.80). On the other hand, healthy individuals increased significantly in relation to basal (p<0.01). The changes that occurred in vascular conductance during the first minute of mental stress, negatively correlated with serum creatinine (r=-0.47, p=0.04). CONCLUSION: The patients with chronic kidney disease have had vasodilation dysfunction during mental stress.