Impacto da volemia sobre a barreira funcional do epitélio intestinal em pacientes críticos com insuficiência cardíaca aguda

Abstract

The regulation of blood volume (volemic homeostasis) depends on the interaction between the cardiovascular, renal, and intestinal systems, whose dynamics are not yet fully understood. In cases of Acute Heart Failure (AHF), these systems may be affected, particularly the intestinal barrier, which undergoes increased permeability. This phenomenon, poorly studied and with limited diagnostic tools, may compromise intestinal epithelial cells. The objective of this study was to investigate how acute changes in blood volume influence the integrity and function of the intestinal barrier in patients with AHF. This was a cross-sectional study, approved by the Research Ethics Committee of the Vale do Acaraú State University (CEP/CONEP), which evaluated intestinal barrier integrity in 80 individuals between March 2022 and January 2024. The sample consisted of 40 patients with AHF (clinical and echocardiographic diagnosis), 14 controls with Coronary Artery Disease (CAD), and 26 healthy controls. Intestinal permeability was measured using the lactulose/mannitol (L:M) urinary excretion ratio by HPLC-PAD. Patients with AHF presented a median L:M ratio of 0.1094 (IQR 25–75%: 0.0411–0.2732), representing an increase of 277.2% compared to healthy volunteers and 466.8% compared to the CAD group, with a statistically significant difference according to the Kruskal-Wallis test (P = 0.001). Kendall’s correlation was used to assess the association between the L:M ratio and Pro-BNP levels, as well as hemodynamic parameters obtained by echocardiography. Multiple regression was performed considering the L:M ratio as the dependent variable and clinical, therapeutic, and in-hospital prognostic characteristics as independent variables. Kendall’s correlation indicated a negative association between the Left Ventricular Outflow Tract (LVOT) Velocity-Time Integral (VTI) and L:M ratio, without statistical significance. Multiple regression did not show significant associations between L:M ratio and clinical, therapeutic, or prognostic variables. Conclusion: Patients with AHF presented increased intestinal permeability, reflected by elevated L:M ratio, suggesting epithelial barrier dysfunction and reduced effective absorptive area. These findings indicate a relevant interaction between cardiovascular dysfunction and intestinal integrity.